Add snappy library. In preparation for upcoming snappy support of OpenVPN

34 files changed, 5485 insertions, 445 deletions

diff --git a/jni/Android.mk b/jni/Android.mk
index 094f6d5f..ab989813 100644
--- a/jni/Android.mk
+++ b/jni/Android.mk
@@ -4,6 +4,7 @@ JNI_DIR := $(call my-dir)
 #USE_POLAR=1
 
 include lzo/Android.mk
+include snappy/Android.mk
 
 include openssl/Android.mk
 
diff --git a/openvpn/Android.mk b/openvpn/Android.mk
index 5659b607..7307a0b3 100644
--- a/openvpn/Android.mk
+++ b/openvpn/Android.mk
@@ -3,13 +3,13 @@ LOCAL_PATH:= $(call my-dir)/
 include $(CLEAR_VARS)
 
 LOCAL_LDLIBS := -lz 
-LOCAL_C_INCLUDES := openssl/include lzo/include openssl/crypto openssl openvpn/src/compat openvpn/src/openvpn openvpn/include google-breakpad/src google-breakpad/src/common/android/include polarssl/include
+LOCAL_C_INCLUDES := openssl/include lzo/include openssl/crypto openssl openvpn/src/compat openvpn/src/openvpn openvpn/include google-breakpad/src google-breakpad/src/common/android/include polarssl/include snappy
 
 
 #LOCAL_STATIC_LIBRARIES :=  libssl_static libcrypto_static  liblzo-static
 
 LOCAL_CFLAGS= -DHAVE_CONFIG_H -DTARGET_ABI=\"${TARGET_ABI}\"
-LOCAL_STATIC_LIBRARIES :=  liblzo-static
+LOCAL_STATIC_LIBRARIES :=  liblzo-static snappy-static
 
 ifeq ($(USE_POLAR),1)
 LOCAL_STATIC_LIBRARIES +=  polarssl-static
@@ -99,7 +99,10 @@ LOCAL_SRC_FILES:= \
 	src/openvpn/ssl_verify_openssl.c \
 	src/openvpn/ssl_verify_polarssl.c \
 	src/openvpn/status.c \
-	src/openvpn/tun.c  
+	src/openvpn/tun.c \
+	src/openvpn/snappy.c \
+	src/openvpn/comp.c \
+	src/openvpn/compstub.c
 
 ifeq ($(WITH_BREAKPAD),1)
 LOCAL_SRC_FILES+=src/openvpn/breakpad.cpp
diff --git a/openvpn/config.h b/openvpn/config.h
index c525e37f..098bf421 100644
--- a/openvpn/config.h
+++ b/openvpn/config.h
@@ -539,6 +539,7 @@
 
 /* Use LZO compression library */
 #define ENABLE_LZO 1
+#define ENABLE_SNAPPY 1
 
 /* Enable PKCS11 capability */
 /* #undef USE_PKCS11 */
diff --git a/openvpn/configure.ac b/openvpn/configure.ac
index 7b35e504..5da5772b 100644
--- a/openvpn/configure.ac
+++ b/openvpn/configure.ac
@@ -46,11 +46,16 @@ AC_ARG_ENABLE(
 	[enable_lzo="yes"]
 )
 
-AC_ARG_ENABLE(
-	[lzo-stub],
-	[AS_HELP_STRING([--enable-lzo-stub], [don't compile LZO compression support but still allow limited interoperability with LZO-enabled peers @<:@default=no@:>@])],
-	,
-	[enable_lzo_stub="no"]
+AC_ARG_ENABLE(snappy,
+	[  --disable-snappy        Disable Snappy compression support],
+	[enable_snappy="$enableval"],
+	[enable_snappy="yes"]
+)
+
+AC_ARG_ENABLE(comp-stub,
+	[  --enable-comp-stub      Don't compile compression support but still allow limited interoperability with compression-enabled peers],
+	[enable_comp_stub="$enableval"],
+	[enable_comp_stub="no"]
 )
 
 AC_ARG_ENABLE(
@@ -895,6 +900,46 @@ if test "${have_lzo}" = "yes"; then
 	CFLAGS="${saved_CFLAGS}"
 fi
 
+dnl
+dnl check for Snappy library
+dnl
+
+AC_ARG_VAR([SNAPPY_CFLAGS], [C compiler flags for snappy])
+AC_ARG_VAR([SNAPPY_LIBS], [linker flags for snappy])
+if test "$enable_snappy" = "yes" && test "$enable_comp_stub" = "no"; then
+    AC_CHECKING([for Snappy Library and Header files])
+    havesnappylib=1
+
+    # if SNAPPY_LIBS is set, we assume it will work, otherwise test
+    if test -z "${SNAPPY_LIBS}"; then
+	AC_CHECK_LIB(snappy, snappy_compress,
+	    [ SNAPPY_LIBS="-lsnappy" ],
+	    [
+	        AC_MSG_RESULT([Snappy library not found.])
+	        havesnappylib=0
+	    ])
+    fi
+
+    saved_CFLAGS="${CFLAGS}"
+    CFLAGS="${CFLAGS} ${SNAPPY_CFLAGS}"
+    AC_CHECK_HEADER(snappy-c.h,
+       ,
+       [
+	   AC_MSG_RESULT([Snappy headers not found.])
+	   havesnappylib=0
+       ])
+
+    if test $havesnappylib = 0 ; then
+	AC_MSG_RESULT([Snappy library available from http://code.google.com/p/snappy/])
+        AC_MSG_ERROR([Or try ./configure --disable-snappy OR ./configure --enable-comp-stub])
+    fi
+    OPTIONAL_SNAPPY_CFLAGS="${SNAPPY_CFLAGS}"
+    OPTIONAL_SNAPPY_LIBS="${SNAPPY_LIBS}"
+    AC_DEFINE(ENABLE_SNAPPY, 1, [Enable Snappy compression library])
+    CFLAGS="${saved_CFLAGS}"
+fi
+
+
 AC_MSG_CHECKING([git checkout])
 GIT_CHECKOUT="no"
 if test -n "${GIT}" -a -d "${srcdir}/.git"; then
@@ -1003,10 +1048,10 @@ if test "${enable_lzo}" = "yes"; then
 	OPTIONAL_LZO_LIBS="${LZO_LIBS}"
 	AC_DEFINE([ENABLE_LZO], [1], [Enable LZO compression library])
 fi
-if test "${enable_lzo_stub}" = "yes"; then
-	test "${enable_lzo}" = "yes" && AC_MSG_ERROR([Cannot have both lzo stub and lzo enabled])
-	AC_DEFINE([ENABLE_LZO_STUB], [1], [Enable LZO stub capability])
-	AC_DEFINE([ENABLE_LZO], [1], [Enable LZO compression library])
+if test "${enable_comp_stub}" = "yes"; then
+	test "${enable_lzo}" = "yes" && AC_MSG_ERROR([Cannot have both comp stub and lzo enabled (use --disable-lzo)])
+	test "${enable_snappy}" = "yes" && AC_MSG_ERROR([Cannot have both comp stub and snappy enabled (use --disable-snappy)])
+	AC_DEFINE([ENABLE_COMP_STUB], [1], [Enable compression stub capability])
 fi
 
 if test "${enable_pkcs11}" = "yes"; then
@@ -1060,6 +1105,8 @@ AC_SUBST([OPTIONAL_CRYPTO_CFLAGS])
 AC_SUBST([OPTIONAL_CRYPTO_LIBS])
 AC_SUBST([OPTIONAL_LZO_CFLAGS])
 AC_SUBST([OPTIONAL_LZO_LIBS])
+AC_SUBST([OPTIONAL_SNAPPY_CFLAGS])
+AC_SUBST([OPTIONAL_SNAPPY_LIBS])
 AC_SUBST([OPTIONAL_PKCS11_HELPER_CFLAGS])
 AC_SUBST([OPTIONAL_PKCS11_HELPER_LIBS])
 
diff --git a/openvpn/doc/openvpn.8 b/openvpn/doc/openvpn.8
index 2f6b32c4..4ae351a0 100644
--- a/openvpn/doc/openvpn.8
+++ b/openvpn/doc/openvpn.8
@@ -2351,12 +2351,32 @@ consecutive messages in the same category.  This is useful to
 limit repetitive logging of similar message types.
 .\"*********************************************************
 .TP
+.B \-\-compress [algorithm]
+Enable a compression algorithm.
+
+The
+.B algorithm
+parameter may be "snappy", "lzo", or empty.  Snappy and LZO
+are different compression algorithms, with Snappy generally
+offering the best performance.
+
+If the
+.B algorithm
+parameter is empty, compression will be turned off, but the packet
+framing for compression will still be enabled, allowing a different
+setting to be pushed later.
+.\"*********************************************************
+.TP
 .B \-\-comp-lzo [mode]
-Use fast LZO compression \-\- may add up to 1 byte per
+Use LZO compression \-\- may add up to 1 byte per
 packet for incompressible data.
 .B mode
 may be "yes", "no", or "adaptive" (default).
 
+This option is deprecated in favor of the newer
+.B --compress
+option.
+
 In a server mode setup, it is possible to selectively turn
 compression on or off for individual clients.
 
diff --git a/openvpn/src/openvpn/Makefile.am b/openvpn/src/openvpn/Makefile.am
index 5d38628d..70e19c2c 100644
--- a/openvpn/src/openvpn/Makefile.am
+++ b/openvpn/src/openvpn/Makefile.am
@@ -26,6 +26,7 @@ AM_CFLAGS = \
 	$(TAP_CFLAGS) \
 	$(OPTIONAL_CRYPTO_CFLAGS) \
 	$(OPTIONAL_LZO_CFLAGS) \
+	$(OPTIONAL_SNAPPY_CFLAGS) \
 	$(OPTIONAL_PKCS11_HELPER_CFLAGS)
 if WIN32
 # we want unicode entry point but not the macro
@@ -41,6 +42,7 @@ openvpn_SOURCES = \
 	circ_list.h \
 	clinat.c clinat.h \
 	common.h \
+	comp.c comp.h compstub.c \
 	crypto.c crypto.h crypto_backend.h \
 	crypto_openssl.c crypto_openssl.h \
 	crypto_polarssl.c crypto_polarssl.h \
@@ -98,6 +100,7 @@ openvpn_SOURCES = \
 	session_id.c session_id.h \
 	shaper.c shaper.h \
 	sig.c sig.h \
+	snappy.c snappy.h \
 	socket.c socket.h \
 	socks.c socks.h \
 	ssl.c ssl.h  ssl_backend.h \
@@ -116,6 +119,7 @@ openvpn_LDADD = \
 	$(top_builddir)/src/compat/libcompat.la \
 	$(SOCKETS_LIBS) \
 	$(OPTIONAL_LZO_LIBS) \
+	$(OPTIONAL_SNAPPY_LIBS) \
 	$(OPTIONAL_PKCS11_HELPER_LIBS) \
 	$(OPTIONAL_CRYPTO_LIBS) \
 	$(OPTIONAL_SELINUX_LIBS) \
diff --git a/openvpn/src/openvpn/forward.c b/openvpn/src/openvpn/forward.c
index 9e9c406c..9fcae11b 100644
--- a/openvpn/src/openvpn/forward.c
+++ b/openvpn/src/openvpn/forward.c
@@ -444,10 +444,10 @@ encrypt_sign (struct context *c, bool comp_frag)
 
   if (comp_frag)
     {
-#ifdef ENABLE_LZO
+#ifdef USE_COMP
       /* Compress the packet. */
-      if (lzo_defined (&c->c2.lzo_compwork))
-	lzo_compress (&c->c2.buf, b->lzo_compress_buf, &c->c2.lzo_compwork, &c->c2.frame);
+      if (c->c2.comp_context)
+	(*c->c2.comp_context->alg.compress)(&c->c2.buf, b->compress_buf, c->c2.comp_context, &c->c2.frame);
 #endif
 #ifdef ENABLE_FRAGMENT
       if (c->c2.fragment)
@@ -846,10 +846,10 @@ process_incoming_link (struct context *c)
 	fragment_incoming (c->c2.fragment, &c->c2.buf, &c->c2.frame_fragment);
 #endif
 
-#ifdef ENABLE_LZO
+#ifdef USE_COMP
       /* decompress the incoming packet */
-      if (lzo_defined (&c->c2.lzo_compwork))
-	lzo_decompress (&c->c2.buf, c->c2.buffers->lzo_decompress_buf, &c->c2.lzo_compwork, &c->c2.frame);
+      if (c->c2.comp_context)
+	(*c->c2.comp_context->alg.decompress)(&c->c2.buf, c->c2.buffers->decompress_buf, c->c2.comp_context, &c->c2.frame);
 #endif
 
 #ifdef PACKET_TRUNCATION_CHECK
diff --git a/openvpn/src/openvpn/init.c b/openvpn/src/openvpn/init.c
index be2ca9df..4af79657 100644
--- a/openvpn/src/openvpn/init.c
+++ b/openvpn/src/openvpn/init.c
@@ -1783,14 +1783,12 @@ do_deferred_options (struct context *c, const unsigned int found)
     }
 #endif
 
-#ifdef ENABLE_LZO
+#ifdef USE_COMP
   if (found & OPT_P_COMP)
     {
-      if (lzo_defined (&c->c2.lzo_compwork))
-	{
-	  msg (D_PUSH, "OPTIONS IMPORT: LZO parms modified");
-	  lzo_modify_flags (&c->c2.lzo_compwork, c->options.lzo);
-	}
+      msg (D_PUSH, "OPTIONS IMPORT: compression parms modified");
+      comp_uninit (c->c2.comp_context);
+      c->c2.comp_context = comp_init (&c->options.comp);
     }
 #endif
 
@@ -2279,6 +2277,10 @@ do_init_crypto_tls (struct context *c, const unsigned int flags)
 #endif
 #endif
 
+#ifdef USE_COMP
+  to.comp_options = options->comp;
+#endif
+
   /* TLS handshake authentication (--tls-auth) */
   if (options->tls_auth_file)
     {
@@ -2361,30 +2363,50 @@ do_init_crypto (struct context *c, const unsigned int flags)
 static void
 do_init_frame (struct context *c)
 {
-#ifdef ENABLE_LZO
+#ifdef USE_COMP
   /*
-   * Initialize LZO compression library.
+   * modify frame parameters if compression is enabled
    */
-  if (c->options.lzo & LZO_SELECTED)
+  if (comp_enabled(&c->options.comp))
     {
-      lzo_adjust_frame_parameters (&c->c2.frame);
+      comp_add_to_extra_frame (&c->c2.frame);
 
+#if !defined(ENABLE_SNAPPY)
       /*
-       * LZO usage affects buffer alignment.
+       * Compression usage affects buffer alignment when non-swapped algs
+       * such as LZO is used.
+       * Newer algs like Snappy and comp-stub with COMP_F_SWAP don't need
+       * any special alignment because of the control-byte swap approach.
+       * LZO alignment (on the other hand) is problematic because
+       * the presence of the control byte means that either the output of
+       * decryption must be written to an unaligned buffer, or the input
+       * to compression (or packet dispatch if packet is uncompressed)
+       * must be read from an unaligned buffer.
+       * This code tries to align the input to compression (or packet
+       * dispatch if packet is uncompressed) at the cost of requiring
+       * decryption output to be written to an unaligned buffer, so
+       * it's more of a tradeoff than an optimal solution and we don't
+       * include it when we are doing a modern build with Snappy.
+       * Strictly speaking, on the server it would be better to execute
+       * this code for every connection after we decide the compression
+       * method, but currently the frame code doesn't appear to be
+       * flexible enough for this, since the frame is already established
+       * before it is known which compression options will be pushed.
        */
-      if (CIPHER_ENABLED (c))
+      if (comp_unswapped_prefix (&c->options.comp) && CIPHER_ENABLED (c))
 	{
-	  frame_add_to_align_adjust (&c->c2.frame, LZO_PREFIX_LEN);
+	  frame_add_to_align_adjust (&c->c2.frame, COMP_PREFIX_LEN);
 	  frame_or_align_flags (&c->c2.frame,
 				FRAME_HEADROOM_MARKER_FRAGMENT
 				|FRAME_HEADROOM_MARKER_DECRYPT);
 	}
+#endif
 
 #ifdef ENABLE_FRAGMENT
-      lzo_adjust_frame_parameters (&c->c2.frame_fragment_omit);	/* omit LZO frame delta from final frame_fragment */
+      comp_add_to_extra_frame (&c->c2.frame_fragment_omit); /* omit compression frame delta from final frame_fragment */
 #endif
     }
-#endif /* ENABLE_LZO */
+#endif /* USE_COMP */
 
 #ifdef ENABLE_SOCKS
   /*
@@ -2413,6 +2435,17 @@ do_init_frame (struct context *c)
    */
   frame_finalize_options (c, NULL);
 
+#ifdef USE_COMP
+  /*
+   * Modify frame parameters if compression is compiled in.
+   * Should be called after frame_finalize_options.
+   */
+  comp_add_to_extra_buffer (&c->c2.frame);
+#ifdef ENABLE_FRAGMENT
+  comp_add_to_extra_buffer (&c->c2.frame_fragment_omit); /* omit compression frame delta from final frame_fragment */
+#endif
+#endif /* USE_COMP */
+
 #ifdef ENABLE_FRAGMENT
   /*
    * Set frame parameter for fragment code.  This is necessary because
@@ -2538,9 +2571,9 @@ init_context_buffers (const struct frame *frame)
   b->decrypt_buf = alloc_buf (BUF_SIZE (frame));
 #endif
 
-#ifdef ENABLE_LZO
-  b->lzo_compress_buf = alloc_buf (BUF_SIZE (frame));
-  b->lzo_decompress_buf = alloc_buf (BUF_SIZE (frame));
+#ifdef USE_COMP
+  b->compress_buf = alloc_buf (BUF_SIZE (frame));
+  b->decompress_buf = alloc_buf (BUF_SIZE (frame));
 #endif
 
   return b;
@@ -2555,9 +2588,9 @@ free_context_buffers (struct context_buffers *b)
       free_buf (&b->read_tun_buf);
       free_buf (&b->aux_buf);
 
-#ifdef ENABLE_LZO
-      free_buf (&b->lzo_compress_buf);
-      free_buf (&b->lzo_decompress_buf);
+#ifdef USE_COMP
+      free_buf (&b->compress_buf);
+      free_buf (&b->decompress_buf);
 #endif
 
 #ifdef ENABLE_CRYPTO
@@ -3402,10 +3435,10 @@ init_instance (struct context *c, const struct env_set *env, const unsigned int
       goto sig;
   }
 
-#ifdef ENABLE_LZO
-  /* initialize LZO compression library. */
-  if ((options->lzo & LZO_SELECTED) && (c->mode == CM_P2P || child))
-    lzo_compress_init (&c->c2.lzo_compwork, options->lzo);
+#ifdef USE_COMP
+  /* initialize compression library. */
+  if (comp_enabled(&options->comp) && (c->mode == CM_P2P || child))
+    c->c2.comp_context = comp_init (&options->comp);
 #endif
 
   /* initialize MTU variables */
@@ -3519,9 +3552,12 @@ close_instance (struct context *c)
 	/* if xinetd/inetd mode, don't allow restart */
 	do_close_check_if_restart_permitted (c);
 
-#ifdef ENABLE_LZO
-	if (lzo_defined (&c->c2.lzo_compwork))
-	  lzo_compress_uninit (&c->c2.lzo_compwork);
+#ifdef USE_COMP
+	if (c->c2.comp_context)
+	  {
+	    comp_uninit (c->c2.comp_context);
+	    c->c2.comp_context = NULL;
+	  }
 #endif
 
 	/* free buffers */
@@ -3645,6 +3681,10 @@ inherit_context_child (struct context *dest,
       dest->c2.link_socket_info->lsa = &dest->c1.link_socket_addr;
       dest->c2.link_socket_info->connection_established = false;
     }
+
+#ifdef USE_COMP
+  dest->c2.comp_context = NULL;
+#endif
 }
 
 void
@@ -3693,6 +3733,10 @@ inherit_context_top (struct context *dest,
   dest->c2.event_set = NULL;
   if (proto_is_dgram(src->options.ce.proto))
     do_event_set_init (dest, false);
+
+#ifdef USE_COMP
+  dest->c2.comp_context = NULL;
+#endif
 }
 
 void
diff --git a/openvpn/src/openvpn/lzo.c b/openvpn/src/openvpn/lzo.c
index 195b8194..daa02ed0 100644
--- a/openvpn/src/openvpn/lzo.c
+++ b/openvpn/src/openvpn/lzo.c
@@ -34,15 +34,17 @@
 
 #include "syshead.h"
 
-#ifdef ENABLE_LZO
+#if defined(ENABLE_LZO)
 
-#include "lzo.h"
+#include "comp.h"
 #include "error.h"
 #include "otime.h"
 
 #include "memdbg.h"
 
-#ifndef ENABLE_LZO_STUB
+/* Initial command byte to tell our peer if we compressed */
+#define LZO_COMPRESS_BYTE 0x66
+
 /**
  * Perform adaptive compression housekeeping.
  *
@@ -97,101 +99,69 @@ lzo_adaptive_compress_data (struct lzo_adaptive_compress *ac, int n_total, int n
   ac->n_comp += n_comp;
 }
 
-#endif /* ENABLE_LZO_STUB */
-
-void lzo_adjust_frame_parameters (struct frame *frame)
-{
-  /* Leave room for our one-byte compressed/didn't-compress prefix byte. */
-  frame_add_to_extra_frame (frame, LZO_PREFIX_LEN);
-
-  /* Leave room for compression buffer to expand in worst case scenario
-     where data is totally uncompressible */
-  frame_add_to_extra_buffer (frame, LZO_EXTRA_BUFFER (EXPANDED_SIZE(frame)));
-}
-
-void
-lzo_compress_init (struct lzo_compress_workspace *lzowork, unsigned int flags)
+static void
+lzo_compress_init (struct compress_context *compctx)
 {
-  CLEAR (*lzowork);
-
-  lzowork->flags = flags;
-#ifndef ENABLE_LZO_STUB
-  lzowork->wmem_size = LZO_WORKSPACE;
-
+  msg (D_INIT_MEDIUM, "LZO compression initializing");
+  ASSERT(!(compctx->flags & COMP_F_SWAP));
+  compctx->wu.lzo.wmem_size = LZO_WORKSPACE;
   if (lzo_init () != LZO_E_OK)
     msg (M_FATAL, "Cannot initialize LZO compression library");
-  lzowork->wmem = (lzo_voidp) lzo_malloc (lzowork->wmem_size);
-  check_malloc_return (lzowork->wmem);
-  msg (D_INIT_MEDIUM, "LZO compression initialized");
-#else
-  msg (D_INIT_MEDIUM, "LZO stub compression initialized");
-#endif
-  lzowork->defined = true;
+  compctx->wu.lzo.wmem = (lzo_voidp) lzo_malloc (compctx->wu.lzo.wmem_size);
+  check_malloc_return (compctx->wu.lzo.wmem);
 }
 
-void
-lzo_compress_uninit (struct lzo_compress_workspace *lzowork)
+static void
+lzo_compress_uninit (struct compress_context *compctx)
 {
-  if (lzowork)
-    {
-      ASSERT (lzowork->defined);
-#ifndef ENABLE_LZO_STUB
-      lzo_free (lzowork->wmem);
-      lzowork->wmem = NULL;
-#endif
-      lzowork->defined = false;
-    }
+  lzo_free (compctx->wu.lzo.wmem);
+  compctx->wu.lzo.wmem = NULL;
 }
 
 static inline bool
-lzo_compression_enabled (struct lzo_compress_workspace *lzowork)
+lzo_compression_enabled (struct compress_context *compctx)
 {
-#ifndef ENABLE_LZO_STUB
-  if ((lzowork->flags & (LZO_SELECTED|LZO_ON)) == (LZO_SELECTED|LZO_ON))
+  if (compctx->flags & COMP_F_ASYM)
+    return false;
+  else
     {
-      if (lzowork->flags & LZO_ADAPTIVE)
-	return lzo_adaptive_compress_test (&lzowork->ac);
+      if (compctx->flags & COMP_F_ADAPTIVE)
+	return lzo_adaptive_compress_test (&compctx->wu.lzo.ac);
       else
 	return true;
     }
-#endif
-  return false;
 }
 
-void
+static void
 lzo_compress (struct buffer *buf, struct buffer work,
-	      struct lzo_compress_workspace *lzowork,
+	      struct compress_context *compctx,
 	      const struct frame* frame)
 {
-#ifndef ENABLE_LZO_STUB
   lzo_uint zlen = 0;
   int err;
   bool compressed = false;
-#endif
-
-  ASSERT (lzowork->defined);
 
   if (buf->len <= 0)
     return;
 
-#ifndef ENABLE_LZO_STUB
   /*
    * In order to attempt compression, length must be at least COMPRESS_THRESHOLD,
    * and our adaptive level must give the OK.
    */
-  if (buf->len >= COMPRESS_THRESHOLD && lzo_compression_enabled (lzowork))
+  if (buf->len >= COMPRESS_THRESHOLD && lzo_compression_enabled (compctx))
     {
+      const size_t ps = PAYLOAD_SIZE (frame);
       ASSERT (buf_init (&work, FRAME_HEADROOM (frame)));
-      ASSERT (buf_safe (&work, LZO_EXTRA_BUFFER (PAYLOAD_SIZE (frame))));
+      ASSERT (buf_safe (&work, ps + COMP_EXTRA_BUFFER (ps)));
 
-      if (!(buf->len <= PAYLOAD_SIZE (frame)))
+      if (buf->len > ps)
 	{
 	  dmsg (D_COMP_ERRORS, "LZO compression buffer overflow");
 	  buf->len = 0;
 	  return;
 	}
 
-      err = LZO_COMPRESS (BPTR (buf), BLEN (buf), BPTR (&work), &zlen, lzowork->wmem);
+      err = LZO_COMPRESS (BPTR (buf), BLEN (buf), BPTR (&work), &zlen, compctx->wu.lzo.wmem);
       if (err != LZO_E_OK)
 	{
 	  dmsg (D_COMP_ERRORS, "LZO compression error: %d", err);
@@ -203,43 +173,38 @@ lzo_compress (struct buffer *buf, struct buffer work,
       work.len = zlen;
       compressed = true;
 
-      dmsg (D_COMP, "compress %d -> %d", buf->len, work.len);
-      lzowork->pre_compress += buf->len;
-      lzowork->post_compress += work.len;
+      dmsg (D_COMP, "LZO compress %d -> %d", buf->len, work.len);
+      compctx->pre_compress += buf->len;
+      compctx->post_compress += work.len;
 
       /* tell adaptive level about our success or lack thereof in getting any size reduction */
-      if (lzowork->flags & LZO_ADAPTIVE)
-	lzo_adaptive_compress_data (&lzowork->ac, buf->len, work.len);
+      if (compctx->flags & COMP_F_ADAPTIVE)
+	lzo_adaptive_compress_data (&compctx->wu.lzo.ac, buf->len, work.len);
     }
 
   /* did compression save us anything ? */
   if (compressed && work.len < buf->len)
     {
       uint8_t *header = buf_prepend (&work, 1);
-      *header = YES_COMPRESS;
+      *header = LZO_COMPRESS_BYTE;
       *buf = work;
     }
   else
-#endif
     {
       uint8_t *header = buf_prepend (buf, 1);
-      *header = NO_COMPRESS;
+      *header = NO_COMPRESS_BYTE;
     }
 }
 
-void
+static void
 lzo_decompress (struct buffer *buf, struct buffer work,
-		struct lzo_compress_workspace *lzowork,
+		struct compress_context *compctx,
 		const struct frame* frame)
 {
-#ifndef ENABLE_LZO_STUB
   lzo_uint zlen = EXPANDED_SIZE (frame);
   int err;
-#endif
   uint8_t c;		/* flag indicating whether or not our peer compressed */
 
-  ASSERT (lzowork->defined);
-
   if (buf->len <= 0)
     return;
 
@@ -248,12 +213,11 @@ lzo_decompress (struct buffer *buf, struct buffer work,
   c = *BPTR (buf);
   ASSERT (buf_advance (buf, 1));
 
-  if (c == YES_COMPRESS)	/* packet was compressed */
+  if (c == LZO_COMPRESS_BYTE)	/* packet was compressed */
     {
-#ifndef ENABLE_LZO_STUB
       ASSERT (buf_safe (&work, zlen));
       err = LZO_DECOMPRESS (BPTR (buf), BLEN (buf), BPTR (&work), &zlen,
-			    lzowork->wmem);
+			    compctx->wu.lzo.wmem);
       if (err != LZO_E_OK)
 	{
 	  dmsg (D_COMP_ERRORS, "LZO decompression error: %d", err);
@@ -264,18 +228,13 @@ lzo_decompress (struct buffer *buf, struct buffer work,
       ASSERT (buf_safe (&work, zlen));
       work.len = zlen;
 
-      dmsg (D_COMP, "decompress %d -> %d", buf->len, work.len);
-      lzowork->pre_decompress += buf->len;
-      lzowork->post_decompress += work.len;
+      dmsg (D_COMP, "LZO decompress %d -> %d", buf->len, work.len);
+      compctx->pre_decompress += buf->len;
+      compctx->post_decompress += work.len;
 
       *buf = work;
-#else
-      dmsg (D_COMP_ERRORS, "LZO decompression error: LZO capability not compiled");
-      buf->len = 0;
-      return;
-#endif
     }
-  else if (c == NO_COMPRESS)	/* packet was not compressed */
+  else if (c == NO_COMPRESS_BYTE)	/* packet was not compressed */
     {
       ;
     }
@@ -286,24 +245,13 @@ lzo_decompress (struct buffer *buf, struct buffer work,
     }
 }
 
-void
-lzo_modify_flags (struct lzo_compress_workspace *lzowork, unsigned int flags)
-{
-  ASSERT (lzowork->defined);
-  lzowork->flags = flags;
-}
-
-void lzo_print_stats (const struct lzo_compress_workspace *lzo_compwork, struct status_output *so)
-{
-  ASSERT (lzo_compwork->defined);
-
-#ifndef ENABLE_LZO_STUB
-  status_printf (so, "pre-compress bytes," counter_format, lzo_compwork->pre_compress);
-  status_printf (so, "post-compress bytes," counter_format, lzo_compwork->post_compress);
-  status_printf (so, "pre-decompress bytes," counter_format, lzo_compwork->pre_decompress);
-  status_printf (so, "post-decompress bytes," counter_format, lzo_compwork->post_decompress);
-#endif
-}
+const struct compress_alg lzo_alg = {
+  "lzo",
+  lzo_compress_init,
+  lzo_compress_uninit,
+  lzo_compress,
+  lzo_decompress
+};
 
 #else
 static void dummy(void) {}
diff --git a/openvpn/src/openvpn/lzo.h b/openvpn/src/openvpn/lzo.h
index 472204d0..f33e587a 100644
--- a/openvpn/src/openvpn/lzo.h
+++ b/openvpn/src/openvpn/lzo.h
@@ -32,14 +32,13 @@
  */
 
 
-#ifdef ENABLE_LZO
+#if defined(ENABLE_LZO)
 
 /**
  * @addtogroup compression
  * @{
  */
 
-#ifndef ENABLE_LZO_STUB
 #if defined(HAVE_LZO_LZOUTIL_H)
 #include "lzo/lzoutil.h"
 #elif defined(HAVE_LZOUTIL_H)
@@ -50,28 +49,16 @@
 #elif defined(HAVE_LZO1X_H)
 #include "lzo1x.h"
 #endif
-#endif
 
 #include "buffer.h"
 #include "mtu.h"
 #include "common.h"
 #include "status.h"
 
-/**************************************************************************/
-/** @name Bit-flags which control data channel packet compression *//******/
-/** @{ */
-#define LZO_SELECTED   (1<<0)   /**< Bit-flag indicating that compression
-                                 *   of data channel packets is enabled. */
-#define LZO_ON         (1<<1)   /**< Bit-flag indicating that compression
-                                 *   of data channel packets is active. */
-#define LZO_ADAPTIVE   (1<<2)   /**< Bit-flag indicating that adaptive
-                                 *   compression of data channel packets
-                                 *   has been selected. */
-/** @} name Bit-flags which control data channel packet compression *//****/
+extern const struct compress_alg lzo_alg;
 
 /**************************************************************************/
 /** @name LZO library interface defines *//** @{ *//***********************/
-#ifndef ENABLE_LZO_STUB
 #define LZO_COMPRESS    lzo1x_1_15_compress
                                 /**< LZO library compression function.
                                  *
@@ -93,36 +80,11 @@
                                  *   verify the integrity of incoming
                                  *   packets, you might want to consider
                                  *   using the non-safe version. */
-#endif /* ENABLE_LZO_STUB */
 /** @} name LZO library interface *//**************************************/
 
 
 /**************************************************************************/
-/** @name Miscellaneous compression defines *//** @{ *//*******************/
-#define LZO_EXTRA_BUFFER(len) ((len)/8 + 128 + 3)
-                                /**< LZO 2.0 worst-case size expansion. */
-#ifndef ENABLE_LZO_STUB
-#define COMPRESS_THRESHOLD 100  /**< Minimum packet size to attempt
-                                 *   compression. */
-#endif /* ENABLE_LZO_STUB */
-/** @} name Miscellaneous compression defines *//**************************/
-
-
-/**************************************************************************/
-/** @name Compression header defines *//** @{ *//**************************/
-#define LZO_PREFIX_LEN 1        /**< Length in bytes of prepended
-                                 *   compression header. */
-#define YES_COMPRESS 0x66       /**< Single-byte compression header
-                                 *   indicating this packet has been
-                                 *   compressed. */
-#define NO_COMPRESS  0xFA       /**< Single-byte compression header
-                                 *   indicating this packet has not been
-                                 *   compressed. */
-/** @} name Compression header defines *//*********************************/
-
-/**************************************************************************/
 /** @name Adaptive compression defines *//** @{ *//************************/
-#ifndef ENABLE_LZO_STUB
 #define AC_SAMP_SEC    2        /**< Number of seconds in a sample period. */
 #define AC_MIN_BYTES   1000     /**< Minimum number of bytes a sample
                                  *   period must contain for it to be
@@ -132,11 +94,8 @@
                                  *   turned off. */
 #define AC_OFF_SEC     60       /**< Seconds to wait after compression has
                                  *   been turned off before retesting. */
-#endif /* ENABLE_LZO_STUB */
 /** @} name Adaptive compression defines *//*******************************/
 
-#ifndef ENABLE_LZO_STUB
-
 /**
  * Adaptive compression state.
  */
@@ -147,8 +106,6 @@ struct lzo_adaptive_compress {
   int n_comp;
 };
 
-#endif /* ENABLE_LZO_STUB */
-
 
 /**
  * State for the compression and decompression routines.
@@ -162,186 +119,13 @@ struct lzo_adaptive_compress {
  */
 struct lzo_compress_workspace
 {
-  bool defined;
-  unsigned int flags;
-#ifndef ENABLE_LZO_STUB
   lzo_voidp wmem;
   int wmem_size;
   struct lzo_adaptive_compress ac;
-
-  /* statistics */
-  counter_type pre_decompress;
-  counter_type post_decompress;
-  counter_type pre_compress;
-  counter_type post_compress;
-#endif
 };
 
-
-/**************************************************************************/
-/** @name Functions for initialization and cleanup *//** @{ *//************/
-
-/**
- * Adjust %frame parameters for data channel payload compression.
- *
- * Data channel packet compression requires a single-byte header to
- * indicate whether a packet has been compressed or not. The packet
- * handling buffers must also allow for worst-case payload compression
- * where the compressed content size is actually larger than the original
- * content size. This function adjusts the parameters of a given frame
- * structure to include the header and allow for worst-case compression
- * expansion.
- *
- * @param frame        - The frame structure to adjust.
- */
-void lzo_adjust_frame_parameters(struct frame *frame);
-
-/**
- * Initialize a compression workspace structure.
- *
- * This function initializes the given workspace structure \a lzowork.
- * This includes allocating a work buffer for internal use and setting its
- * flags to the given value of \a flags.
- *
- * This function also initializes the lzo library.
- *
- * @param lzowork      - A pointer to the workspace structure to
- *                       initialize.
- * @param flags        - The initial flags to set in the workspace
- *                       structure.
- */
-void lzo_compress_init (struct lzo_compress_workspace *lzowork, unsigned int flags);
-
-/**
- * Cleanup a compression workspace structure.
- *
- * This function cleans up the given workspace structure \a lzowork.  This
- * includes freeing the structure's internal work buffer.
- *
- * @param lzowork      - A pointer to the workspace structure to clean up.
- */
-void lzo_compress_uninit (struct lzo_compress_workspace *lzowork);
-
-/**
- * Set a workspace structure's flags.
- *
- * @param lzowork      - The workspace structure of which to modify the
- *                       flags.
- * @param flags        - The new value to assign to the workspace
- *                       structure's flags.
- */
-void lzo_modify_flags (struct lzo_compress_workspace *lzowork, unsigned int flags);
-
-/** @} name Functions for initialization and cleanup *//*******************/
-
-
-/**************************************************************************/
-/** @name Function for packets to be sent to a remote OpenVPN peer *//*****/
-/** @{ */
-
-/**
- * Process an outgoing packet according to a VPN tunnel's settings.
- * @ingroup compression
- *
- * This function processes the packet contained in \a buf.  Its behavior
- * depends on the settings contained within \a lzowork.  If compression is
- * enabled and active, this function compresses the packet.  After
- * compression, the size of the uncompressed and compressed packets are
- * compared, and the smallest is used.
- *
- * This function prepends a one-byte header indicating whether the packet
- * was or was not compressed, so as to let the peer know how to handle the
- * packet.
- *
- * If an error occurs during processing, an error message is logged and
- * the length of \a buf is set to zero.
- *
- * @param buf          - A pointer to the buffer containing the outgoing
- *                       packet.  This pointer will be modified to point
- *                       to the processed packet on return.
- * @param work         - A preallocated working buffer.
- * @param lzowork      - The compression workspace structure associated
- *                       with this VPN tunnel.
- * @param frame        - The frame parameters of this tunnel.
- *
- * @return Void.\n  On return, \a buf will point to a buffer containing
- *     the processed, possibly compressed, packet data with a compression
- *     header prepended.
- */
-void lzo_compress (struct buffer *buf, struct buffer work,
-		   struct lzo_compress_workspace *lzowork,
-		   const struct frame* frame);
-
-/** @} name Function for packets to be sent to a remote OpenVPN peer *//***/
-
-
-/**************************************************************************/
-/** @name Function for packets received from a remote OpenVPN peer *//*****/
-/** @{ */
-
-/**
- * Inspect an incoming packet and decompress if it is compressed.
- *
- * This function inspects the incoming packet contained in \a buf.  If its
- * one-byte compression header indicates that it was compressed (i.e. \c
- * YES_COMPRESS), then it will be decompressed.  If its header indicates
- * that it was not compressed (i.e. \c NO_COMPRESS), then the buffer is
- * not modified except for removing the compression header.
- *
- * If an error occurs during processing, for example if the compression
- * header has a value other than \c YES_COMPRESS or \c NO_COMPRESS, then
- * the error is logged and the length of \a buf is set to zero.
- *
- * @param buf          - A pointer to the buffer containing the incoming
- *                       packet.  This pointer will be modified to point
- *                       to the processed packet on return.
- * @param work         - A preallocated working buffer.
- * @param lzowork      - The compression workspace structure associated
- *                       with this VPN tunnel.
- * @param frame        - The frame parameters of this tunnel.
- *
- * @return Void.\n  On return, \a buf will point to a buffer containing
- *     the uncompressed packet data and the one-byte compression header
- *     will have been removed.
- */
-void lzo_decompress (struct buffer *buf, struct buffer work,
-		     struct lzo_compress_workspace *lzowork,
-		     const struct frame* frame);
-
-/** @} name Function for packets received from a remote OpenVPN peer *//***/
-
-
-/**************************************************************************/
-/** @name Utility functions *//** @{ *//***********************************/
-
-/**
- * Print statistics on compression and decompression performance.
- *
- * @param lzo_compwork - The workspace structure from which to get the
- *                       statistics.
- * @param so           - The status output structure to which to write the
- *                       statistics.
- */
-void lzo_print_stats (const struct lzo_compress_workspace *lzo_compwork, struct status_output *so);
-
-/**
- * Check whether compression is enabled for a workspace structure.
- *
- * @param lzowork      - The workspace structure to check.
- *
- * @return true if compression is enabled; false otherwise.
- */
-static inline bool
-lzo_defined (const struct lzo_compress_workspace *lzowork)
-{
-  return lzowork->defined;
-}
-
-/** @} name Utility functions *//******************************************/
-
-
 /** @} addtogroup compression */
 
 
-#endif /* ENABLE_LZO */
+#endif /* ENABLE_LZO && USE_COMP */
 #endif
diff --git a/openvpn/src/openvpn/openvpn.h b/openvpn/src/openvpn/openvpn.h
index bdfa6852..606a4f59 100644
--- a/openvpn/src/openvpn/openvpn.h
+++ b/openvpn/src/openvpn/openvpn.h
@@ -31,7 +31,7 @@
 #include "crypto.h"
 #include "ssl.h"
 #include "packet_id.h"
-#include "lzo.h"
+#include "comp.h"
 #include "tun.h"
 #include "interval.h"
 #include "status.h"
@@ -104,10 +104,10 @@ struct context_buffers
   struct buffer decrypt_buf;
 #endif
 
-  /* workspace buffers for LZO compression */
-#ifdef ENABLE_LZO
-  struct buffer lzo_compress_buf;
-  struct buffer lzo_decompress_buf;
+  /* workspace buffers for compression */
+#ifdef USE_COMP
+  struct buffer compress_buf;
+  struct buffer decompress_buf;
 #endif
 
   /*
@@ -372,9 +372,9 @@ struct context_2
 
 #endif /* ENABLE_CRYPTO */
 
-#ifdef ENABLE_LZO
-  struct lzo_compress_workspace lzo_compwork;
-                                /**< Compression workspace used by the
+#ifdef USE_COMP
+  struct compress_context *comp_context;
+                                /**< Compression context used by the
                                  *   \link compression Data Channel
                                  *   Compression module\endlink. */
 #endif
diff --git a/openvpn/src/openvpn/options.c b/openvpn/src/openvpn/options.c
index db1cb33a..7dba31a7 100644
--- a/openvpn/src/openvpn/options.c
+++ b/openvpn/src/openvpn/options.c
@@ -84,13 +84,17 @@ const char title_string[] =
 #endif /* defined(ENABLE_CRYPTO_POLARSSL) */
 #endif /* ENABLE_SSL */
 #endif /* ENABLE_CRYPTO */
+#ifdef USE_COMP
 #ifdef ENABLE_LZO
-#ifdef ENABLE_LZO_STUB
-  " [LZO (STUB)]"
-#else
   " [LZO]"
 #endif
+#ifdef ENABLE_SNAPPY
+  " [SNAPPY]"
+#endif
+#ifdef ENABLE_COMP_STUB
+  " [COMP_STUB]"
 #endif
+#endif /* USE_COMP */
 #if EPOLL
   " [EPOLL]"
 #endif
@@ -362,12 +366,15 @@ static const char usage_message[] =
 #ifdef ENABLE_DEBUG
   "--gremlin mask  : Special stress testing mode (for debugging only).\n"
 #endif
-#ifdef ENABLE_LZO
-  "--comp-lzo      : Use fast LZO compression -- may add up to 1 byte per\n"
+#if defined(USE_COMP)
+  "--compress alg  : Use compression algorithm alg\n"
+#if defined(ENABLE_LZO)
+  "--comp-lzo      : Use LZO compression -- may add up to 1 byte per\n"
   "                  packet for uncompressible data.\n"
   "--comp-noadapt  : Don't use adaptive compression when --comp-lzo\n"
   "                  is specified.\n"
 #endif
+#endif
 #ifdef ENABLE_MANAGEMENT
   "--management ip port [pass] : Enable a TCP server on ip:port to handle\n"
   "                  management functions.  pass is a password file\n"
@@ -1512,8 +1519,9 @@ show_settings (const struct options *o)
 
   SHOW_BOOL (fast_io);
 
-#ifdef ENABLE_LZO
-  SHOW_INT (lzo);
+#ifdef USE_COMP
+  SHOW_INT (comp.alg);
+  SHOW_INT (comp.flags);
 #endif
 
   SHOW_STR (route_script);
@@ -2852,6 +2860,7 @@ pre_pull_restore (struct options *o)
  *                 the other end of the connection]
  *
  * --comp-lzo
+ * --compress alg
  * --fragment
  *
  * Crypto Options:
@@ -2933,9 +2942,9 @@ options_string (const struct options *o,
       tt = NULL;
     }
 
-#ifdef ENABLE_LZO
-  if (o->lzo & LZO_SELECTED)
-    buf_printf (&out, ",comp-lzo");
+#ifdef USE_COMP
+  if (o->comp.alg != COMP_ALG_UNDEF)
+    buf_printf (&out, ",comp-lzo"); /* for compatibility, this simply indicates that compression context is active, not necessarily LZO per-se */
 #endif
 
 #ifdef ENABLE_FRAGMENT
@@ -6039,18 +6048,31 @@ add_option (struct options *options,
       options->passtos = true;
     }
 #endif
-#ifdef ENABLE_LZO
+#if defined(USE_COMP)
   else if (streq (p[0], "comp-lzo"))
     {
       VERIFY_PERMISSION (OPT_P_COMP);
-      if (p[1])
+
+#if defined(ENABLE_LZO)
+      if (p[1] && streq (p[1], "no"))
+#endif
+	{
+	  options->comp.alg = COMP_ALG_STUB;
+	  options->comp.flags = 0;
+	}
+#if defined(ENABLE_LZO)
+      else if (p[1])
 	{
 	  if (streq (p[1], "yes"))
-	    options->lzo = LZO_SELECTED|LZO_ON;
-	  else if (streq (p[1], "no"))
-	    options->lzo = LZO_SELECTED;
+	    {
+	      options->comp.alg = COMP_ALG_LZO;
+	      options->comp.flags = 0;
+	    }
 	  else if (streq (p[1], "adaptive"))
-	    options->lzo = LZO_SELECTED|LZO_ON|LZO_ADAPTIVE;
+	    {
+	      options->comp.alg = COMP_ALG_LZO;
+	      options->comp.flags = COMP_F_ADAPTIVE;
+	    }
 	  else
 	    {
 	      msg (msglevel, "bad comp-lzo option: %s -- must be 'yes', 'no', or 'adaptive'", p[1]);
@@ -6058,14 +6080,54 @@ add_option (struct options *options,
 	    }
 	}
       else
-	options->lzo = LZO_SELECTED|LZO_ON|LZO_ADAPTIVE;
+	{
+	  options->comp.alg = COMP_ALG_LZO;
+	  options->comp.flags = COMP_F_ADAPTIVE;
+	}
+#endif
     }
   else if (streq (p[0], "comp-noadapt"))
     {
       VERIFY_PERMISSION (OPT_P_COMP);
-      options->lzo &= ~LZO_ADAPTIVE;
+      options->comp.flags &= ~COMP_F_ADAPTIVE;
+    }
+  else if (streq (p[0], "compress"))
+    {
+      VERIFY_PERMISSION (OPT_P_COMP);
+      if (p[1])
+	{
+	  if (streq (p[1], "stub"))
+	    {
+	      options->comp.alg = COMP_ALG_STUB;
+	      options->comp.flags = (COMP_F_SWAP|COMP_F_ADVERTISE_STUBS_ONLY);
+	    }
+#if defined(ENABLE_LZO)
+	  else if (streq (p[1], "lzo"))
+	    {
+	      options->comp.alg = COMP_ALG_LZO;
+	      options->comp.flags = 0;
+	    }
+#endif
+#if defined(ENABLE_SNAPPY)
+	  else if (streq (p[1], "snappy"))
+	    {
+	      options->comp.alg = COMP_ALG_SNAPPY;
+	      options->comp.flags = COMP_F_SWAP;
+	    }
+#endif
+	  else
+	    {
+	      msg (msglevel, "bad comp option: %s", p[1]);
+	      goto err;
+	    }
+	}
+      else
+	{
+	  options->comp.alg = COMP_ALG_STUB;
+	  options->comp.flags = COMP_F_SWAP;
+	}
     }
-#endif /* ENABLE_LZO */
+#endif /* USE_COMP */
 #ifdef ENABLE_CRYPTO
   else if (streq (p[0], "show-ciphers"))
     {
diff --git a/openvpn/src/openvpn/options.h b/openvpn/src/openvpn/options.h
index e5de2f10..56359357 100644
--- a/openvpn/src/openvpn/options.h
+++ b/openvpn/src/openvpn/options.h
@@ -39,7 +39,7 @@
 #include "plugin.h"
 #include "manage.h"
 #include "proxy.h"
-#include "lzo.h"
+#include "comp.h"
 #include "pushlist.h"
 #include "clinat.h"
 
@@ -316,9 +316,8 @@ struct options
   /* optimize TUN/TAP/UDP writes */
   bool fast_io;
 
-#ifdef ENABLE_LZO
-  /* LZO_x flags from lzo.h */
-  unsigned int lzo;
+#ifdef USE_COMP
+  struct compress_options comp;
 #endif
 
   /* buffer sizes */
diff --git a/openvpn/src/openvpn/sig.c b/openvpn/src/openvpn/sig.c
index 7ddfd0ed..90e39a42 100644
--- a/openvpn/src/openvpn/sig.c
+++ b/openvpn/src/openvpn/sig.c
@@ -279,9 +279,9 @@ print_status (const struct context *c, struct status_output *so)
   status_printf (so, "TCP/UDP read bytes," counter_format, c->c2.link_read_bytes);
   status_printf (so, "TCP/UDP write bytes," counter_format, c->c2.link_write_bytes);
   status_printf (so, "Auth read bytes," counter_format, c->c2.link_read_bytes_auth);
-#ifdef ENABLE_LZO
-  if (lzo_defined (&c->c2.lzo_compwork))
-    lzo_print_stats (&c->c2.lzo_compwork, so);
+#ifdef USE_COMP
+  if (c->c2.comp_context)
+    comp_print_stats (c->c2.comp_context, so);
 #endif
 #ifdef PACKET_TRUNCATION_CHECK
   status_printf (so, "TUN read truncations," counter_format, c->c2.n_trunc_tun_read);
diff --git a/openvpn/src/openvpn/ssl.c b/openvpn/src/openvpn/ssl.c
index b3673864..7e261e75 100644
--- a/openvpn/src/openvpn/ssl.c
+++ b/openvpn/src/openvpn/ssl.c
@@ -1775,66 +1775,68 @@ push_peer_info(struct buffer *buf, struct tls_session *session)
   bool ret = false;
 
 #ifdef ENABLE_PUSH_PEER_INFO
-  if (session->opt->push_peer_info) /* write peer info */
-    {
-      struct env_set *es = session->opt->es;
-      struct env_item *e;
-      struct buffer out = alloc_buf_gc (512*3, &gc);
+  {
+    struct env_set *es = session->opt->es;
+    struct env_item *e;
+    struct buffer out = alloc_buf_gc (512*3, &gc);
 
-      /* push version */
-      buf_printf (&out, "IV_VER=%s\n", PACKAGE_VERSION);
+    /* push version */
+    buf_printf (&out, "IV_VER=%s\n", PACKAGE_VERSION);
 
-      /* push platform */
+    /* push platform */
 #if defined(TARGET_LINUX)
-      buf_printf (&out, "IV_PLAT=linux\n");
+    buf_printf (&out, "IV_PLAT=linux\n");
 #elif defined(TARGET_SOLARIS)
-      buf_printf (&out, "IV_PLAT=solaris\n");
+    buf_printf (&out, "IV_PLAT=solaris\n");
 #elif defined(TARGET_OPENBSD)
-      buf_printf (&out, "IV_PLAT=openbsd\n");
+    buf_printf (&out, "IV_PLAT=openbsd\n");
 #elif defined(TARGET_DARWIN)
-      buf_printf (&out, "IV_PLAT=mac\n");
+    buf_printf (&out, "IV_PLAT=mac\n");
 #elif defined(TARGET_NETBSD)
-      buf_printf (&out, "IV_PLAT=netbsd\n");
+    buf_printf (&out, "IV_PLAT=netbsd\n");
 #elif defined(TARGET_FREEBSD)
-      buf_printf (&out, "IV_PLAT=freebsd\n");
+    buf_printf (&out, "IV_PLAT=freebsd\n");
 #elif defined(TARGET_ANDROID)
-      buf_printf(&out, "IV_PLAT=android\n");
+    buf_printf (&out, "IV_PLAT=android\n");
 #elif defined(WIN32)
-      buf_printf (&out, "IV_PLAT=win\n");
+    buf_printf (&out, "IV_PLAT=win\n");
 #endif
 
-      /* push mac addr */
-      {
-	struct route_gateway_info rgi;
-	get_default_gateway (&rgi);
-	if (rgi.flags & RGI_HWADDR_DEFINED)
-	  buf_printf (&out, "IV_HWADDR=%s\n", format_hex_ex (rgi.hwaddr, 6, 0, 1, ":", &gc));
-      }
-
-      /* push LZO status */
-#ifdef ENABLE_LZO_STUB
-      buf_printf (&out, "IV_LZO_STUB=1\n");
+    /* push compression status */
+#ifdef USE_COMP
+    comp_generate_peer_info_string(&session->opt->comp_options, &out);
 #endif
 
-      /* push env vars that begin with UV_ */
-      for (e=es->list; e != NULL; e=e->next)
+    if (session->opt->push_peer_info)
+      {
+	/* push mac addr */
 	{
-	  if (e->string)
-	    {
-	      if (!strncmp(e->string, "UV_", 3) && buf_safe(&out, strlen(e->string)+1))
-		buf_printf (&out, "%s\n", e->string);
-	    }
+	  struct route_gateway_info rgi;
+	  get_default_gateway (&rgi);
+	  if (rgi.flags & RGI_HWADDR_DEFINED)
+	    buf_printf (&out, "IV_HWADDR=%s\n", format_hex_ex (rgi.hwaddr, 6, 0, 1, ":", &gc));
 	}
 
-      if (!write_string(buf, BSTR(&out), -1))
-	goto error;
-    }
-  else
+	/* push env vars that begin with UV_ */
+	for (e=es->list; e != NULL; e=e->next)
+	  {
+	    if (e->string)
+	      {
+		if (!strncmp(e->string, "UV_", 3) && buf_safe(&out, strlen(e->string)+1))
+		  buf_printf (&out, "%s\n", e->string);
+	      }
+	  }
+      }
+
+    if (!write_string(buf, BSTR(&out), -1))
+      goto error;
+  }
+#else
+  {
+    if (!write_empty_string (buf)) /* no peer info */
+      goto error;
+  }
 #endif
-    {
-      if (!write_empty_string (buf)) /* no peer info */
-	goto error;
-    }
   ret = true;
 
  error:
diff --git a/openvpn/src/openvpn/ssl_common.h b/openvpn/src/openvpn/ssl_common.h
index c62294f5..47dbefbe 100644
--- a/openvpn/src/openvpn/ssl_common.h
+++ b/openvpn/src/openvpn/ssl_common.h
@@ -285,6 +285,11 @@ struct tls_options
   struct env_set *es;
   const struct plugin_list *plugins;
 
+  /* compression parms */
+#ifdef USE_COMP
+  struct compress_options comp_options;
+#endif
+
   /* configuration file boolean options */
 # define SSLF_CLIENT_CERT_NOT_REQUIRED (1<<0)
 # define SSLF_USERNAME_AS_COMMON_NAME  (1<<1)
diff --git a/openvpn/src/openvpn/syshead.h b/openvpn/src/openvpn/syshead.h
index 0c3e4ee5..2be11159 100644
--- a/openvpn/src/openvpn/syshead.h
+++ b/openvpn/src/openvpn/syshead.h
@@ -720,6 +720,13 @@ socket_defined (const socket_descriptor_t sd)
 #define ENABLE_CLIENT_NAT
 
 /*
+ * Compression support
+ */
+#if defined(ENABLE_SNAPPY) || defined(ENABLE_LZO) || defined(ENABLE_COMP_STUB)
+#define USE_COMP
+#endif
+
+/*
  * Enable --memstats option
  */
 #ifdef TARGET_LINUX
diff --git a/snappy/Android.mk b/snappy/Android.mk
new file mode 100644
index 00000000..cdd26003
--- /dev/null
+++ b/snappy/Android.mk
@@ -0,0 +1,35 @@
+
+LOCAL_PATH:= $(call my-dir)
+
+
+common_SRC_FILES:=  \
+	snappy-c.cc \
+	snappy-sinksource.cc \
+	snappy-stubs-internal.cc \
+	snappy.cc
+
+common_C_INCLUDES += $(LOCAL_PATH)/ $(LOCAL_PATH)/conf
+
+# static library
+# =====================================================
+
+include $(CLEAR_VARS)
+LOCAL_CPP_EXTENSION := .cc
+LOCAL_SRC_FILES:= $(common_SRC_FILES)
+LOCAL_C_INCLUDES:= $(common_C_INCLUDES)
+LOCAL_MODULE := snappy-static
+LOCAL_PRELINK_MODULE:= false
+LOCAL_MODULE_TAGS := optional
+include $(BUILD_STATIC_LIBRARY)
+
+# dynamic library
+# =====================================================
+
+# include $(CLEAR_VARS)
+# LOCAL_SRC_FILES:= $(common_SRC_FILES)
+# LOCAL_C_INCLUDES:= $(common_C_INCLUDES)
+# LOCAL_MODULE := liblzo
+# LOCAL_PRELINK_MODULE:= false
+# LOCAL_MODULE_TAGS := optional
+# include $(BUILD_SHARED_LIBRARY)
+
diff --git a/snappy/COPYING b/snappy/COPYING
new file mode 100644
index 00000000..8d6bd9fe
--- /dev/null
+++ b/snappy/COPYING
@@ -0,0 +1,28 @@
+Copyright 2011, Google Inc.
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are
+met:
+
+    * Redistributions of source code must retain the above copyright
+notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above
+copyright notice, this list of conditions and the following disclaimer
+in the documentation and/or other materials provided with the
+distribution.
+    * Neither the name of Google Inc. nor the names of its
+contributors may be used to endorse or promote products derived from
+this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
diff --git a/snappy/conf/config.h b/snappy/conf/config.h
new file mode 100644
index 00000000..e0bf3214
--- /dev/null
+++ b/snappy/conf/config.h
@@ -0,0 +1,129 @@
+/* config.h.  Generated from config.h.in by configure.  */
+/* config.h.in.  Generated from configure.ac by autoheader.  */
+
+/* Define if building universal (internal helper macro) */
+/* #undef AC_APPLE_UNIVERSAL_BUILD */
+
+/* Define to 1 if the compiler supports __builtin_ctz and friends. */
+#define HAVE_BUILTIN_CTZ 1
+
+/* Define to 1 if the compiler supports __builtin_expect. */
+#define HAVE_BUILTIN_EXPECT 1
+
+/* Define to 1 if you have the <byteswap.h> header file. */
+/* #undef HAVE_BYTESWAP_H */
+
+/* Define to 1 if you have the <dlfcn.h> header file. */
+#define HAVE_DLFCN_H 1
+
+/* Use the gflags package for command-line parsing. */
+/* #undef HAVE_GFLAGS */
+
+/* Defined when Google Test is available. */
+/* #undef HAVE_GTEST */
+
+/* Define to 1 if you have the <inttypes.h> header file. */
+#define HAVE_INTTYPES_H 1
+
+/* Define to 1 if you have the `fastlz' library (-lfastlz). */
+/* #undef HAVE_LIBFASTLZ */
+
+/* Define to 1 if you have the `lzf' library (-llzf). */
+/* #undef HAVE_LIBLZF */
+
+/* Define to 1 if you have the `lzo2' library (-llzo2). */
+/* #undef HAVE_LIBLZO2 */
+
+/* Define to 1 if you have the `quicklz' library (-lquicklz). */
+/* #undef HAVE_LIBQUICKLZ */
+
+/* Define to 1 if you have the `z' library (-lz). */
+#define HAVE_LIBZ 1
+
+/* Define to 1 if you have the <memory.h> header file. */
+#define HAVE_MEMORY_H 1
+
+/* Define to 1 if you have the <stddef.h> header file. */
+#define HAVE_STDDEF_H 1
+
+/* Define to 1 if you have the <stdint.h> header file. */
+#define HAVE_STDINT_H 1
+
+/* Define to 1 if you have the <stdlib.h> header file. */
+#define HAVE_STDLIB_H 1
+
+/* Define to 1 if you have the <strings.h> header file. */
+#define HAVE_STRINGS_H 1
+
+/* Define to 1 if you have the <string.h> header file. */
+#define HAVE_STRING_H 1
+
+/* Define to 1 if you have the <sys/byteswap.h> header file. */
+/* #undef HAVE_SYS_BYTESWAP_H */
+
+/* Define to 1 if you have the <sys/endian.h> header file. */
+/* #undef HAVE_SYS_ENDIAN_H */
+
+/* Define to 1 if you have the <sys/mman.h> header file. */
+#define HAVE_SYS_MMAN_H 1
+
+/* Define to 1 if you have the <sys/resource.h> header file. */
+#define HAVE_SYS_RESOURCE_H 1
+
+/* Define to 1 if you have the <sys/stat.h> header file. */
+#define HAVE_SYS_STAT_H 1
+
+/* Define to 1 if you have the <sys/time.h> header file. */
+#define HAVE_SYS_TIME_H 1
+
+/* Define to 1 if you have the <sys/types.h> header file. */
+#define HAVE_SYS_TYPES_H 1
+
+/* Define to 1 if you have the <unistd.h> header file. */
+#define HAVE_UNISTD_H 1
+
+/* Define to 1 if you have the <windows.h> header file. */
+/* #undef HAVE_WINDOWS_H */
+
+/* Define to the sub-directory in which libtool stores uninstalled libraries.
+   */
+#define LT_OBJDIR ".libs/"
+
+/* Name of package */
+#define PACKAGE "snappy"
+
+/* Define to the address where bug reports for this package should be sent. */
+#define PACKAGE_BUGREPORT ""
+
+/* Define to the full name of this package. */
+#define PACKAGE_NAME "snappy"
+
+/* Define to the full name and version of this package. */
+#define PACKAGE_STRING "snappy 1.1.0"
+
+/* Define to the one symbol short name of this package. */
+#define PACKAGE_TARNAME "snappy"
+
+/* Define to the home page for this package. */
+#define PACKAGE_URL ""
+
+/* Define to the version of this package. */
+#define PACKAGE_VERSION "1.1.0"
+
+/* Define to 1 if you have the ANSI C header files. */
+#define STDC_HEADERS 1
+
+/* Version number of package */
+#define VERSION "1.1.0"
+
+/* Define WORDS_BIGENDIAN to 1 if your processor stores words with the most
+   significant byte first (like Motorola and SPARC, unlike Intel). */
+#if defined AC_APPLE_UNIVERSAL_BUILD
+# if defined __BIG_ENDIAN__
+#  define WORDS_BIGENDIAN 1
+# endif
+#else
+# ifndef WORDS_BIGENDIAN
+/* #  undef WORDS_BIGENDIAN */
+# endif
+#endif
diff --git a/snappy/snappy-c.cc b/snappy/snappy-c.cc
new file mode 100644
index 00000000..473a0b09
--- /dev/null
+++ b/snappy/snappy-c.cc
@@ -0,0 +1,90 @@
+// Copyright 2011 Martin Gieseking <martin.gieseking@uos.de>.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "snappy.h"
+#include "snappy-c.h"
+
+extern "C" {
+
+snappy_status snappy_compress(const char* input,
+                              size_t input_length,
+                              char* compressed,
+                              size_t *compressed_length) {
+  if (*compressed_length < snappy_max_compressed_length(input_length)) {
+    return SNAPPY_BUFFER_TOO_SMALL;
+  }
+  snappy::RawCompress(input, input_length, compressed, compressed_length);
+  return SNAPPY_OK;
+}
+
+snappy_status snappy_uncompress(const char* compressed,
+                                size_t compressed_length,
+                                char* uncompressed,
+                                size_t* uncompressed_length) {
+  size_t real_uncompressed_length;
+  if (!snappy::GetUncompressedLength(compressed,
+                                     compressed_length,
+                                     &real_uncompressed_length)) {
+    return SNAPPY_INVALID_INPUT;
+  }
+  if (*uncompressed_length < real_uncompressed_length) {
+    return SNAPPY_BUFFER_TOO_SMALL;
+  }
+  if (!snappy::RawUncompress(compressed, compressed_length, uncompressed)) {
+    return SNAPPY_INVALID_INPUT;
+  }
+  *uncompressed_length = real_uncompressed_length;
+  return SNAPPY_OK;
+}
+
+size_t snappy_max_compressed_length(size_t source_length) {
+  return snappy::MaxCompressedLength(source_length);
+}
+
+snappy_status snappy_uncompressed_length(const char *compressed,
+                                         size_t compressed_length,
+                                         size_t *result) {
+  if (snappy::GetUncompressedLength(compressed,
+                                    compressed_length,
+                                    result)) {
+    return SNAPPY_OK;
+  } else {
+    return SNAPPY_INVALID_INPUT;
+  }
+}
+
+snappy_status snappy_validate_compressed_buffer(const char *compressed,
+                                                size_t compressed_length) {
+  if (snappy::IsValidCompressedBuffer(compressed, compressed_length)) {
+    return SNAPPY_OK;
+  } else {
+    return SNAPPY_INVALID_INPUT;
+  }
+}
+
+}  // extern "C"
diff --git a/snappy/snappy-c.h b/snappy/snappy-c.h
new file mode 100644
index 00000000..c6c2a860
--- /dev/null
+++ b/snappy/snappy-c.h
@@ -0,0 +1,138 @@
+/*
+ * Copyright 2011 Martin Gieseking <martin.gieseking@uos.de>.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ * Plain C interface (a wrapper around the C++ implementation).
+ */
+
+#ifndef UTIL_SNAPPY_OPENSOURCE_SNAPPY_C_H_
+#define UTIL_SNAPPY_OPENSOURCE_SNAPPY_C_H_
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include <stddef.h>
+
+/*
+ * Return values; see the documentation for each function to know
+ * what each can return.
+ */
+typedef enum {
+  SNAPPY_OK = 0,
+  SNAPPY_INVALID_INPUT = 1,
+  SNAPPY_BUFFER_TOO_SMALL = 2
+} snappy_status;
+
+/*
+ * Takes the data stored in "input[0..input_length-1]" and stores
+ * it in the array pointed to by "compressed".
+ *
+ * <compressed_length> signals the space available in "compressed".
+ * If it is not at least equal to "snappy_max_compressed_length(input_length)",
+ * SNAPPY_BUFFER_TOO_SMALL is returned. After successful compression,
+ * <compressed_length> contains the true length of the compressed output,
+ * and SNAPPY_OK is returned.
+ *
+ * Example:
+ *   size_t output_length = snappy_max_compressed_length(input_length);
+ *   char* output = (char*)malloc(output_length);
+ *   if (snappy_compress(input, input_length, output, &output_length)
+ *       == SNAPPY_OK) {
+ *     ... Process(output, output_length) ...
+ *   }
+ *   free(output);
+ */
+snappy_status snappy_compress(const char* input,
+                              size_t input_length,
+                              char* compressed,
+                              size_t* compressed_length);
+
+/*
+ * Given data in "compressed[0..compressed_length-1]" generated by
+ * calling the snappy_compress routine, this routine stores
+ * the uncompressed data to
+ *   uncompressed[0..uncompressed_length-1].
+ * Returns failure (a value not equal to SNAPPY_OK) if the message
+ * is corrupted and could not be decrypted.
+ *
+ * <uncompressed_length> signals the space available in "uncompressed".
+ * If it is not at least equal to the value returned by
+ * snappy_uncompressed_length for this stream, SNAPPY_BUFFER_TOO_SMALL
+ * is returned. After successful decompression, <uncompressed_length>
+ * contains the true length of the decompressed output.
+ *
+ * Example:
+ *   size_t output_length;
+ *   if (snappy_uncompressed_length(input, input_length, &output_length)
+ *       != SNAPPY_OK) {
+ *     ... fail ...
+ *   }
+ *   char* output = (char*)malloc(output_length);
+ *   if (snappy_uncompress(input, input_length, output, &output_length)
+ *       == SNAPPY_OK) {
+ *     ... Process(output, output_length) ...
+ *   }
+ *   free(output);
+ */
+snappy_status snappy_uncompress(const char* compressed,
+                                size_t compressed_length,
+                                char* uncompressed,
+                                size_t* uncompressed_length);
+
+/*
+ * Returns the maximal size of the compressed representation of
+ * input data that is "source_length" bytes in length.
+ */
+size_t snappy_max_compressed_length(size_t source_length);
+
+/*
+ * REQUIRES: "compressed[]" was produced by snappy_compress()
+ * Returns SNAPPY_OK and stores the length of the uncompressed data in
+ * *result normally. Returns SNAPPY_INVALID_INPUT on parsing error.
+ * This operation takes O(1) time.
+ */
+snappy_status snappy_uncompressed_length(const char* compressed,
+                                         size_t compressed_length,
+                                         size_t* result);
+
+/*
+ * Check if the contents of "compressed[]" can be uncompressed successfully.
+ * Does not return the uncompressed data; if so, returns SNAPPY_OK,
+ * or if not, returns SNAPPY_INVALID_INPUT.
+ * Takes time proportional to compressed_length, but is usually at least a
+ * factor of four faster than actual decompression.
+ */
+snappy_status snappy_validate_compressed_buffer(const char* compressed,
+                                                size_t compressed_length);
+
+#ifdef __cplusplus
+}  // extern "C"
+#endif
+
+#endif  /* UTIL_SNAPPY_OPENSOURCE_SNAPPY_C_H_ */
diff --git a/snappy/snappy-internal.h b/snappy/snappy-internal.h
new file mode 100644
index 00000000..c99d3313
--- /dev/null
+++ b/snappy/snappy-internal.h
@@ -0,0 +1,150 @@
+// Copyright 2008 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Internals shared between the Snappy implementation and its unittest.
+
+#ifndef UTIL_SNAPPY_SNAPPY_INTERNAL_H_
+#define UTIL_SNAPPY_SNAPPY_INTERNAL_H_
+
+#include "snappy-stubs-internal.h"
+
+namespace snappy {
+namespace internal {
+
+class WorkingMemory {
+ public:
+  WorkingMemory() : large_table_(NULL) { }
+  ~WorkingMemory() { delete[] large_table_; }
+
+  // Allocates and clears a hash table using memory in "*this",
+  // stores the number of buckets in "*table_size" and returns a pointer to
+  // the base of the hash table.
+  uint16* GetHashTable(size_t input_size, int* table_size);
+
+ private:
+  uint16 small_table_[1<<10];    // 2KB
+  uint16* large_table_;          // Allocated only when needed
+
+  DISALLOW_COPY_AND_ASSIGN(WorkingMemory);
+};
+
+// Flat array compression that does not emit the "uncompressed length"
+// prefix. Compresses "input" string to the "*op" buffer.
+//
+// REQUIRES: "input_length <= kBlockSize"
+// REQUIRES: "op" points to an array of memory that is at least
+// "MaxCompressedLength(input_length)" in size.
+// REQUIRES: All elements in "table[0..table_size-1]" are initialized to zero.
+// REQUIRES: "table_size" is a power of two
+//
+// Returns an "end" pointer into "op" buffer.
+// "end - op" is the compressed size of "input".
+char* CompressFragment(const char* input,
+                       size_t input_length,
+                       char* op,
+                       uint16* table,
+                       const int table_size);
+
+// Return the largest n such that
+//
+//   s1[0,n-1] == s2[0,n-1]
+//   and n <= (s2_limit - s2).
+//
+// Does not read *s2_limit or beyond.
+// Does not read *(s1 + (s2_limit - s2)) or beyond.
+// Requires that s2_limit >= s2.
+//
+// Separate implementation for x86_64, for speed.  Uses the fact that
+// x86_64 is little endian.
+#if defined(ARCH_K8)
+static inline int FindMatchLength(const char* s1,
+                                  const char* s2,
+                                  const char* s2_limit) {
+  assert(s2_limit >= s2);
+  int matched = 0;
+
+  // Find out how long the match is. We loop over the data 64 bits at a
+  // time until we find a 64-bit block that doesn't match; then we find
+  // the first non-matching bit and use that to calculate the total
+  // length of the match.
+  while (PREDICT_TRUE(s2 <= s2_limit - 8)) {
+    if (PREDICT_FALSE(UNALIGNED_LOAD64(s2) == UNALIGNED_LOAD64(s1 + matched))) {
+      s2 += 8;
+      matched += 8;
+    } else {
+      // On current (mid-2008) Opteron models there is a 3% more
+      // efficient code sequence to find the first non-matching byte.
+      // However, what follows is ~10% better on Intel Core 2 and newer,
+      // and we expect AMD's bsf instruction to improve.
+      uint64 x = UNALIGNED_LOAD64(s2) ^ UNALIGNED_LOAD64(s1 + matched);
+      int matching_bits = Bits::FindLSBSetNonZero64(x);
+      matched += matching_bits >> 3;
+      return matched;
+    }
+  }
+  while (PREDICT_TRUE(s2 < s2_limit)) {
+    if (PREDICT_TRUE(s1[matched] == *s2)) {
+      ++s2;
+      ++matched;
+    } else {
+      return matched;
+    }
+  }
+  return matched;
+}
+#else
+static inline int FindMatchLength(const char* s1,
+                                  const char* s2,
+                                  const char* s2_limit) {
+  // Implementation based on the x86-64 version, above.
+  assert(s2_limit >= s2);
+  int matched = 0;
+
+  while (s2 <= s2_limit - 4 &&
+         UNALIGNED_LOAD32(s2) == UNALIGNED_LOAD32(s1 + matched)) {
+    s2 += 4;
+    matched += 4;
+  }
+  if (LittleEndian::IsLittleEndian() && s2 <= s2_limit - 4) {
+    uint32 x = UNALIGNED_LOAD32(s2) ^ UNALIGNED_LOAD32(s1 + matched);
+    int matching_bits = Bits::FindLSBSetNonZero(x);
+    matched += matching_bits >> 3;
+  } else {
+    while ((s2 < s2_limit) && (s1[matched] == *s2)) {
+      ++s2;
+      ++matched;
+    }
+  }
+  return matched;
+}
+#endif
+
+}  // end namespace internal
+}  // end namespace snappy
+
+#endif  // UTIL_SNAPPY_SNAPPY_INTERNAL_H_
diff --git a/snappy/snappy-sinksource.cc b/snappy/snappy-sinksource.cc
new file mode 100644
index 00000000..5844552c
--- /dev/null
+++ b/snappy/snappy-sinksource.cc
@@ -0,0 +1,71 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <string.h>
+
+#include "snappy-sinksource.h"
+
+namespace snappy {
+
+Source::~Source() { }
+
+Sink::~Sink() { }
+
+char* Sink::GetAppendBuffer(size_t length, char* scratch) {
+  return scratch;
+}
+
+ByteArraySource::~ByteArraySource() { }
+
+size_t ByteArraySource::Available() const { return left_; }
+
+const char* ByteArraySource::Peek(size_t* len) {
+  *len = left_;
+  return ptr_;
+}
+
+void ByteArraySource::Skip(size_t n) {
+  left_ -= n;
+  ptr_ += n;
+}
+
+UncheckedByteArraySink::~UncheckedByteArraySink() { }
+
+void UncheckedByteArraySink::Append(const char* data, size_t n) {
+  // Do no copying if the caller filled in the result of GetAppendBuffer()
+  if (data != dest_) {
+    memcpy(dest_, data, n);
+  }
+  dest_ += n;
+}
+
+char* UncheckedByteArraySink::GetAppendBuffer(size_t len, char* scratch) {
+  return dest_;
+}
+
+}
diff --git a/snappy/snappy-sinksource.h b/snappy/snappy-sinksource.h
new file mode 100644
index 00000000..faabfa1e
--- /dev/null
+++ b/snappy/snappy-sinksource.h
@@ -0,0 +1,137 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_
+#define UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_
+
+#include <stddef.h>
+
+
+namespace snappy {
+
+// A Sink is an interface that consumes a sequence of bytes.
+class Sink {
+ public:
+  Sink() { }
+  virtual ~Sink();
+
+  // Append "bytes[0,n-1]" to this.
+  virtual void Append(const char* bytes, size_t n) = 0;
+
+  // Returns a writable buffer of the specified length for appending.
+  // May return a pointer to the caller-owned scratch buffer which
+  // must have at least the indicated length.  The returned buffer is
+  // only valid until the next operation on this Sink.
+  //
+  // After writing at most "length" bytes, call Append() with the
+  // pointer returned from this function and the number of bytes
+  // written.  Many Append() implementations will avoid copying
+  // bytes if this function returned an internal buffer.
+  //
+  // If a non-scratch buffer is returned, the caller may only pass a
+  // prefix of it to Append().  That is, it is not correct to pass an
+  // interior pointer of the returned array to Append().
+  //
+  // The default implementation always returns the scratch buffer.
+  virtual char* GetAppendBuffer(size_t length, char* scratch);
+
+
+ private:
+  // No copying
+  Sink(const Sink&);
+  void operator=(const Sink&);
+};
+
+// A Source is an interface that yields a sequence of bytes
+class Source {
+ public:
+  Source() { }
+  virtual ~Source();
+
+  // Return the number of bytes left to read from the source
+  virtual size_t Available() const = 0;
+
+  // Peek at the next flat region of the source.  Does not reposition
+  // the source.  The returned region is empty iff Available()==0.
+  //
+  // Returns a pointer to the beginning of the region and store its
+  // length in *len.
+  //
+  // The returned region is valid until the next call to Skip() or
+  // until this object is destroyed, whichever occurs first.
+  //
+  // The returned region may be larger than Available() (for example
+  // if this ByteSource is a view on a substring of a larger source).
+  // The caller is responsible for ensuring that it only reads the
+  // Available() bytes.
+  virtual const char* Peek(size_t* len) = 0;
+
+  // Skip the next n bytes.  Invalidates any buffer returned by
+  // a previous call to Peek().
+  // REQUIRES: Available() >= n
+  virtual void Skip(size_t n) = 0;
+
+ private:
+  // No copying
+  Source(const Source&);
+  void operator=(const Source&);
+};
+
+// A Source implementation that yields the contents of a flat array
+class ByteArraySource : public Source {
+ public:
+  ByteArraySource(const char* p, size_t n) : ptr_(p), left_(n) { }
+  virtual ~ByteArraySource();
+  virtual size_t Available() const;
+  virtual const char* Peek(size_t* len);
+  virtual void Skip(size_t n);
+ private:
+  const char* ptr_;
+  size_t left_;
+};
+
+// A Sink implementation that writes to a flat array without any bound checks.
+class UncheckedByteArraySink : public Sink {
+ public:
+  explicit UncheckedByteArraySink(char* dest) : dest_(dest) { }
+  virtual ~UncheckedByteArraySink();
+  virtual void Append(const char* data, size_t n);
+  virtual char* GetAppendBuffer(size_t len, char* scratch);
+
+  // Return the current output pointer so that a caller can see how
+  // many bytes were produced.
+  // Note: this is not a Sink method.
+  char* CurrentDestination() const { return dest_; }
+ private:
+  char* dest_;
+};
+
+
+}
+
+#endif  // UTIL_SNAPPY_SNAPPY_SINKSOURCE_H_
diff --git a/snappy/snappy-stubs-internal.cc b/snappy/snappy-stubs-internal.cc
new file mode 100644
index 00000000..6ed33437
--- /dev/null
+++ b/snappy/snappy-stubs-internal.cc
@@ -0,0 +1,42 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <algorithm>
+#include <string>
+
+#include "snappy-stubs-internal.h"
+
+namespace snappy {
+
+void Varint::Append32(string* s, uint32 value) {
+  char buf[Varint::kMax32];
+  const char* p = Varint::Encode32(buf, value);
+  s->append(buf, p - buf);
+}
+
+}  // namespace snappy
diff --git a/snappy/snappy-stubs-internal.h b/snappy/snappy-stubs-internal.h
new file mode 100644
index 00000000..12393b62
--- /dev/null
+++ b/snappy/snappy-stubs-internal.h
@@ -0,0 +1,491 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various stubs for the open-source version of Snappy.
+
+#ifndef UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_
+#define UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_
+
+#ifdef HAVE_CONFIG_H
+#include "config.h"
+#endif
+
+#include <string>
+
+#include <assert.h>
+#include <stdlib.h>
+#include <string.h>
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
+#include "snappy-stubs-public.h"
+
+#if defined(__x86_64__)
+
+// Enable 64-bit optimized versions of some routines.
+#define ARCH_K8 1
+
+#endif
+
+// Needed by OS X, among others.
+#ifndef MAP_ANONYMOUS
+#define MAP_ANONYMOUS MAP_ANON
+#endif
+
+// Pull in std::min, std::ostream, and the likes. This is safe because this
+// header file is never used from any public header files.
+using namespace std;
+
+// The size of an array, if known at compile-time.
+// Will give unexpected results if used on a pointer.
+// We undefine it first, since some compilers already have a definition.
+#ifdef ARRAYSIZE
+#undef ARRAYSIZE
+#endif
+#define ARRAYSIZE(a) (sizeof(a) / sizeof(*(a)))
+
+// Static prediction hints.
+#ifdef HAVE_BUILTIN_EXPECT
+#define PREDICT_FALSE(x) (__builtin_expect(x, 0))
+#define PREDICT_TRUE(x) (__builtin_expect(!!(x), 1))
+#else
+#define PREDICT_FALSE(x) x
+#define PREDICT_TRUE(x) x
+#endif
+
+// This is only used for recomputing the tag byte table used during
+// decompression; for simplicity we just remove it from the open-source
+// version (anyone who wants to regenerate it can just do the call
+// themselves within main()).
+#define DEFINE_bool(flag_name, default_value, description) \
+  bool FLAGS_ ## flag_name = default_value
+#define DECLARE_bool(flag_name) \
+  extern bool FLAGS_ ## flag_name
+
+namespace snappy {
+
+static const uint32 kuint32max = static_cast<uint32>(0xFFFFFFFF);
+static const int64 kint64max = static_cast<int64>(0x7FFFFFFFFFFFFFFFLL);
+
+// Potentially unaligned loads and stores.
+
+// x86 and PowerPC can simply do these loads and stores native.
+
+#if defined(__i386__) || defined(__x86_64__) || defined(__powerpc__)
+
+#define UNALIGNED_LOAD16(_p) (*reinterpret_cast<const uint16 *>(_p))
+#define UNALIGNED_LOAD32(_p) (*reinterpret_cast<const uint32 *>(_p))
+#define UNALIGNED_LOAD64(_p) (*reinterpret_cast<const uint64 *>(_p))
+
+#define UNALIGNED_STORE16(_p, _val) (*reinterpret_cast<uint16 *>(_p) = (_val))
+#define UNALIGNED_STORE32(_p, _val) (*reinterpret_cast<uint32 *>(_p) = (_val))
+#define UNALIGNED_STORE64(_p, _val) (*reinterpret_cast<uint64 *>(_p) = (_val))
+
+// ARMv7 and newer support native unaligned accesses, but only of 16-bit
+// and 32-bit values (not 64-bit); older versions either raise a fatal signal,
+// do an unaligned read and rotate the words around a bit, or do the reads very
+// slowly (trip through kernel mode). There's no simple #define that says just
+// “ARMv7 or higher”, so we have to filter away all ARMv5 and ARMv6
+// sub-architectures.
+//
+// This is a mess, but there's not much we can do about it.
+
+#elif defined(__arm__) && \
+      !defined(__ARM_ARCH_4__) && \
+      !defined(__ARM_ARCH_4T__) && \
+      !defined(__ARM_ARCH_5__) && \
+      !defined(__ARM_ARCH_5T__) && \
+      !defined(__ARM_ARCH_5TE__) && \
+      !defined(__ARM_ARCH_5TEJ__) && \
+      !defined(__ARM_ARCH_6__) && \
+      !defined(__ARM_ARCH_6J__) && \
+      !defined(__ARM_ARCH_6K__) && \
+      !defined(__ARM_ARCH_6Z__) && \
+      !defined(__ARM_ARCH_6ZK__) && \
+      !defined(__ARM_ARCH_6T2__)
+
+#define UNALIGNED_LOAD16(_p) (*reinterpret_cast<const uint16 *>(_p))
+#define UNALIGNED_LOAD32(_p) (*reinterpret_cast<const uint32 *>(_p))
+
+#define UNALIGNED_STORE16(_p, _val) (*reinterpret_cast<uint16 *>(_p) = (_val))
+#define UNALIGNED_STORE32(_p, _val) (*reinterpret_cast<uint32 *>(_p) = (_val))
+
+// TODO(user): NEON supports unaligned 64-bit loads and stores.
+// See if that would be more efficient on platforms supporting it,
+// at least for copies.
+
+inline uint64 UNALIGNED_LOAD64(const void *p) {
+  uint64 t;
+  memcpy(&t, p, sizeof t);
+  return t;
+}
+
+inline void UNALIGNED_STORE64(void *p, uint64 v) {
+  memcpy(p, &v, sizeof v);
+}
+
+#else
+
+// These functions are provided for architectures that don't support
+// unaligned loads and stores.
+
+inline uint16 UNALIGNED_LOAD16(const void *p) {
+  uint16 t;
+  memcpy(&t, p, sizeof t);
+  return t;
+}
+
+inline uint32 UNALIGNED_LOAD32(const void *p) {
+  uint32 t;
+  memcpy(&t, p, sizeof t);
+  return t;
+}
+
+inline uint64 UNALIGNED_LOAD64(const void *p) {
+  uint64 t;
+  memcpy(&t, p, sizeof t);
+  return t;
+}
+
+inline void UNALIGNED_STORE16(void *p, uint16 v) {
+  memcpy(p, &v, sizeof v);
+}
+
+inline void UNALIGNED_STORE32(void *p, uint32 v) {
+  memcpy(p, &v, sizeof v);
+}
+
+inline void UNALIGNED_STORE64(void *p, uint64 v) {
+  memcpy(p, &v, sizeof v);
+}
+
+#endif
+
+// This can be more efficient than UNALIGNED_LOAD64 + UNALIGNED_STORE64
+// on some platforms, in particular ARM.
+inline void UnalignedCopy64(const void *src, void *dst) {
+  if (sizeof(void *) == 8) {
+    UNALIGNED_STORE64(dst, UNALIGNED_LOAD64(src));
+  } else {
+    const char *src_char = reinterpret_cast<const char *>(src);
+    char *dst_char = reinterpret_cast<char *>(dst);
+
+    UNALIGNED_STORE32(dst_char, UNALIGNED_LOAD32(src_char));
+    UNALIGNED_STORE32(dst_char + 4, UNALIGNED_LOAD32(src_char + 4));
+  }
+}
+
+// The following guarantees declaration of the byte swap functions.
+#ifdef WORDS_BIGENDIAN
+
+#ifdef HAVE_SYS_BYTEORDER_H
+#include <sys/byteorder.h>
+#endif
+
+#ifdef HAVE_SYS_ENDIAN_H
+#include <sys/endian.h>
+#endif
+
+#ifdef _MSC_VER
+#include <stdlib.h>
+#define bswap_16(x) _byteswap_ushort(x)
+#define bswap_32(x) _byteswap_ulong(x)
+#define bswap_64(x) _byteswap_uint64(x)
+
+#elif defined(__APPLE__)
+// Mac OS X / Darwin features
+#include <libkern/OSByteOrder.h>
+#define bswap_16(x) OSSwapInt16(x)
+#define bswap_32(x) OSSwapInt32(x)
+#define bswap_64(x) OSSwapInt64(x)
+
+#elif defined(HAVE_BYTESWAP_H)
+#include <byteswap.h>
+
+#elif defined(bswap32)
+// FreeBSD defines bswap{16,32,64} in <sys/endian.h> (already #included).
+#define bswap_16(x) bswap16(x)
+#define bswap_32(x) bswap32(x)
+#define bswap_64(x) bswap64(x)
+
+#elif defined(BSWAP_64)
+// Solaris 10 defines BSWAP_{16,32,64} in <sys/byteorder.h> (already #included).
+#define bswap_16(x) BSWAP_16(x)
+#define bswap_32(x) BSWAP_32(x)
+#define bswap_64(x) BSWAP_64(x)
+
+#else
+
+inline uint16 bswap_16(uint16 x) {
+  return (x << 8) | (x >> 8);
+}
+
+inline uint32 bswap_32(uint32 x) {
+  x = ((x & 0xff00ff00UL) >> 8) | ((x & 0x00ff00ffUL) << 8);
+  return (x >> 16) | (x << 16);
+}
+
+inline uint64 bswap_64(uint64 x) {
+  x = ((x & 0xff00ff00ff00ff00ULL) >> 8) | ((x & 0x00ff00ff00ff00ffULL) << 8);
+  x = ((x & 0xffff0000ffff0000ULL) >> 16) | ((x & 0x0000ffff0000ffffULL) << 16);
+  return (x >> 32) | (x << 32);
+}
+
+#endif
+
+#endif  // WORDS_BIGENDIAN
+
+// Convert to little-endian storage, opposite of network format.
+// Convert x from host to little endian: x = LittleEndian.FromHost(x);
+// convert x from little endian to host: x = LittleEndian.ToHost(x);
+//
+//  Store values into unaligned memory converting to little endian order:
+//    LittleEndian.Store16(p, x);
+//
+//  Load unaligned values stored in little endian converting to host order:
+//    x = LittleEndian.Load16(p);
+class LittleEndian {
+ public:
+  // Conversion functions.
+#ifdef WORDS_BIGENDIAN
+
+  static uint16 FromHost16(uint16 x) { return bswap_16(x); }
+  static uint16 ToHost16(uint16 x) { return bswap_16(x); }
+
+  static uint32 FromHost32(uint32 x) { return bswap_32(x); }
+  static uint32 ToHost32(uint32 x) { return bswap_32(x); }
+
+  static bool IsLittleEndian() { return false; }
+
+#else  // !defined(WORDS_BIGENDIAN)
+
+  static uint16 FromHost16(uint16 x) { return x; }
+  static uint16 ToHost16(uint16 x) { return x; }
+
+  static uint32 FromHost32(uint32 x) { return x; }
+  static uint32 ToHost32(uint32 x) { return x; }
+
+  static bool IsLittleEndian() { return true; }
+
+#endif  // !defined(WORDS_BIGENDIAN)
+
+  // Functions to do unaligned loads and stores in little-endian order.
+  static uint16 Load16(const void *p) {
+    return ToHost16(UNALIGNED_LOAD16(p));
+  }
+
+  static void Store16(void *p, uint16 v) {
+    UNALIGNED_STORE16(p, FromHost16(v));
+  }
+
+  static uint32 Load32(const void *p) {
+    return ToHost32(UNALIGNED_LOAD32(p));
+  }
+
+  static void Store32(void *p, uint32 v) {
+    UNALIGNED_STORE32(p, FromHost32(v));
+  }
+};
+
+// Some bit-manipulation functions.
+class Bits {
+ public:
+  // Return floor(log2(n)) for positive integer n.  Returns -1 iff n == 0.
+  static int Log2Floor(uint32 n);
+
+  // Return the first set least / most significant bit, 0-indexed.  Returns an
+  // undefined value if n == 0.  FindLSBSetNonZero() is similar to ffs() except
+  // that it's 0-indexed.
+  static int FindLSBSetNonZero(uint32 n);
+  static int FindLSBSetNonZero64(uint64 n);
+
+ private:
+  DISALLOW_COPY_AND_ASSIGN(Bits);
+};
+
+#ifdef HAVE_BUILTIN_CTZ
+
+inline int Bits::Log2Floor(uint32 n) {
+  return n == 0 ? -1 : 31 ^ __builtin_clz(n);
+}
+
+inline int Bits::FindLSBSetNonZero(uint32 n) {
+  return __builtin_ctz(n);
+}
+
+inline int Bits::FindLSBSetNonZero64(uint64 n) {
+  return __builtin_ctzll(n);
+}
+
+#else  // Portable versions.
+
+inline int Bits::Log2Floor(uint32 n) {
+  if (n == 0)
+    return -1;
+  int log = 0;
+  uint32 value = n;
+  for (int i = 4; i >= 0; --i) {
+    int shift = (1 << i);
+    uint32 x = value >> shift;
+    if (x != 0) {
+      value = x;
+      log += shift;
+    }
+  }
+  assert(value == 1);
+  return log;
+}
+
+inline int Bits::FindLSBSetNonZero(uint32 n) {
+  int rc = 31;
+  for (int i = 4, shift = 1 << 4; i >= 0; --i) {
+    const uint32 x = n << shift;
+    if (x != 0) {
+      n = x;
+      rc -= shift;
+    }
+    shift >>= 1;
+  }
+  return rc;
+}
+
+// FindLSBSetNonZero64() is defined in terms of FindLSBSetNonZero().
+inline int Bits::FindLSBSetNonZero64(uint64 n) {
+  const uint32 bottombits = static_cast<uint32>(n);
+  if (bottombits == 0) {
+    // Bottom bits are zero, so scan in top bits
+    return 32 + FindLSBSetNonZero(static_cast<uint32>(n >> 32));
+  } else {
+    return FindLSBSetNonZero(bottombits);
+  }
+}
+
+#endif  // End portable versions.
+
+// Variable-length integer encoding.
+class Varint {
+ public:
+  // Maximum lengths of varint encoding of uint32.
+  static const int kMax32 = 5;
+
+  // Attempts to parse a varint32 from a prefix of the bytes in [ptr,limit-1].
+  // Never reads a character at or beyond limit.  If a valid/terminated varint32
+  // was found in the range, stores it in *OUTPUT and returns a pointer just
+  // past the last byte of the varint32. Else returns NULL.  On success,
+  // "result <= limit".
+  static const char* Parse32WithLimit(const char* ptr, const char* limit,
+                                      uint32* OUTPUT);
+
+  // REQUIRES   "ptr" points to a buffer of length sufficient to hold "v".
+  // EFFECTS    Encodes "v" into "ptr" and returns a pointer to the
+  //            byte just past the last encoded byte.
+  static char* Encode32(char* ptr, uint32 v);
+
+  // EFFECTS    Appends the varint representation of "value" to "*s".
+  static void Append32(string* s, uint32 value);
+};
+
+inline const char* Varint::Parse32WithLimit(const char* p,
+                                            const char* l,
+                                            uint32* OUTPUT) {
+  const unsigned char* ptr = reinterpret_cast<const unsigned char*>(p);
+  const unsigned char* limit = reinterpret_cast<const unsigned char*>(l);
+  uint32 b, result;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result = b & 127;          if (b < 128) goto done;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result |= (b & 127) <<  7; if (b < 128) goto done;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result |= (b & 127) << 14; if (b < 128) goto done;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result |= (b & 127) << 21; if (b < 128) goto done;
+  if (ptr >= limit) return NULL;
+  b = *(ptr++); result |= (b & 127) << 28; if (b < 16) goto done;
+  return NULL;       // Value is too long to be a varint32
+ done:
+  *OUTPUT = result;
+  return reinterpret_cast<const char*>(ptr);
+}
+
+inline char* Varint::Encode32(char* sptr, uint32 v) {
+  // Operate on characters as unsigneds
+  unsigned char* ptr = reinterpret_cast<unsigned char*>(sptr);
+  static const int B = 128;
+  if (v < (1<<7)) {
+    *(ptr++) = v;
+  } else if (v < (1<<14)) {
+    *(ptr++) = v | B;
+    *(ptr++) = v>>7;
+  } else if (v < (1<<21)) {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = v>>14;
+  } else if (v < (1<<28)) {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = (v>>14) | B;
+    *(ptr++) = v>>21;
+  } else {
+    *(ptr++) = v | B;
+    *(ptr++) = (v>>7) | B;
+    *(ptr++) = (v>>14) | B;
+    *(ptr++) = (v>>21) | B;
+    *(ptr++) = v>>28;
+  }
+  return reinterpret_cast<char*>(ptr);
+}
+
+// If you know the internal layout of the std::string in use, you can
+// replace this function with one that resizes the string without
+// filling the new space with zeros (if applicable) --
+// it will be non-portable but faster.
+inline void STLStringResizeUninitialized(string* s, size_t new_size) {
+  s->resize(new_size);
+}
+
+// Return a mutable char* pointing to a string's internal buffer,
+// which may not be null-terminated. Writing through this pointer will
+// modify the string.
+//
+// string_as_array(&str)[i] is valid for 0 <= i < str.size() until the
+// next call to a string method that invalidates iterators.
+//
+// As of 2006-04, there is no standard-blessed way of getting a
+// mutable reference to a string's internal buffer. However, issue 530
+// (http://www.open-std.org/JTC1/SC22/WG21/docs/lwg-defects.html#530)
+// proposes this as the method. It will officially be part of the standard
+// for C++0x. This should already work on all current implementations.
+inline char* string_as_array(string* str) {
+  return str->empty() ? NULL : &*str->begin();
+}
+
+}  // namespace snappy
+
+#endif  // UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_INTERNAL_H_
diff --git a/snappy/snappy-stubs-public.h b/snappy/snappy-stubs-public.h
new file mode 100644
index 00000000..96d88650
--- /dev/null
+++ b/snappy/snappy-stubs-public.h
@@ -0,0 +1,85 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: sesse@google.com (Steinar H. Gunderson)
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various type stubs for the open-source version of Snappy.
+//
+// This file cannot include config.h, as it is included from snappy.h,
+// which is a public header. Instead, snappy-stubs-public.h is generated by
+// from snappy-stubs-public.h.in at configure time.
+
+#ifndef UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+#define UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+
+#if 1
+#include <stdint.h>
+#endif
+
+#if 1
+#include <stddef.h>
+#endif
+
+#define SNAPPY_MAJOR 1
+#define SNAPPY_MINOR 1
+#define SNAPPY_PATCHLEVEL 0
+#define SNAPPY_VERSION \
+    ((SNAPPY_MAJOR << 16) | (SNAPPY_MINOR << 8) | SNAPPY_PATCHLEVEL)
+
+#include <string>
+
+namespace snappy {
+
+#if 1
+typedef int8_t int8;
+typedef uint8_t uint8;
+typedef int16_t int16;
+typedef uint16_t uint16;
+typedef int32_t int32;
+typedef uint32_t uint32;
+typedef int64_t int64;
+typedef uint64_t uint64;
+#else
+typedef signed char int8;
+typedef unsigned char uint8;
+typedef short int16;
+typedef unsigned short uint16;
+typedef int int32;
+typedef unsigned int uint32;
+typedef long long int64;
+typedef unsigned long long uint64;
+#endif
+
+typedef std::string string;
+
+#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&);               \
+  void operator=(const TypeName&)
+
+}  // namespace snappy
+
+#endif  // UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
diff --git a/snappy/snappy-stubs-public.h.in b/snappy/snappy-stubs-public.h.in
new file mode 100644
index 00000000..f0babcbe
--- /dev/null
+++ b/snappy/snappy-stubs-public.h.in
@@ -0,0 +1,85 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+// Author: sesse@google.com (Steinar H. Gunderson)
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various type stubs for the open-source version of Snappy.
+//
+// This file cannot include config.h, as it is included from snappy.h,
+// which is a public header. Instead, snappy-stubs-public.h is generated by
+// from snappy-stubs-public.h.in at configure time.
+
+#ifndef UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+#define UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
+
+#if @ac_cv_have_stdint_h@
+#include <stdint.h>
+#endif
+
+#if @ac_cv_have_stddef_h@
+#include <stddef.h>
+#endif
+
+#define SNAPPY_MAJOR @SNAPPY_MAJOR@
+#define SNAPPY_MINOR @SNAPPY_MINOR@
+#define SNAPPY_PATCHLEVEL @SNAPPY_PATCHLEVEL@
+#define SNAPPY_VERSION \
+    ((SNAPPY_MAJOR << 16) | (SNAPPY_MINOR << 8) | SNAPPY_PATCHLEVEL)
+
+#include <string>
+
+namespace snappy {
+
+#if @ac_cv_have_stdint_h@
+typedef int8_t int8;
+typedef uint8_t uint8;
+typedef int16_t int16;
+typedef uint16_t uint16;
+typedef int32_t int32;
+typedef uint32_t uint32;
+typedef int64_t int64;
+typedef uint64_t uint64;
+#else
+typedef signed char int8;
+typedef unsigned char uint8;
+typedef short int16;
+typedef unsigned short uint16;
+typedef int int32;
+typedef unsigned int uint32;
+typedef long long int64;
+typedef unsigned long long uint64;
+#endif
+
+typedef std::string string;
+
+#define DISALLOW_COPY_AND_ASSIGN(TypeName) \
+  TypeName(const TypeName&);               \
+  void operator=(const TypeName&)
+
+}  // namespace snappy
+
+#endif  // UTIL_SNAPPY_OPENSOURCE_SNAPPY_STUBS_PUBLIC_H_
diff --git a/snappy/snappy-test.cc b/snappy/snappy-test.cc
new file mode 100644
index 00000000..46194109
--- /dev/null
+++ b/snappy/snappy-test.cc
@@ -0,0 +1,606 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various stubs for the unit tests for the open-source version of Snappy.
+
+#include "snappy-test.h"
+
+#ifdef HAVE_WINDOWS_H
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#endif
+
+#include <algorithm>
+
+DEFINE_bool(run_microbenchmarks, true,
+            "Run microbenchmarks before doing anything else.");
+
+namespace snappy {
+
+string ReadTestDataFile(const string& base, size_t size_limit) {
+  string contents;
+  const char* srcdir = getenv("srcdir");  // This is set by Automake.
+  string prefix;
+  if (srcdir) {
+    prefix = string(srcdir) + "/";
+  }
+  file::GetContents(prefix + "testdata/" + base, &contents, file::Defaults()
+      ).CheckSuccess();
+  if (size_limit > 0) {
+    contents = contents.substr(0, size_limit);
+  }
+  return contents;
+}
+
+string ReadTestDataFile(const string& base) {
+  return ReadTestDataFile(base, 0);
+}
+
+string StringPrintf(const char* format, ...) {
+  char buf[4096];
+  va_list ap;
+  va_start(ap, format);
+  vsnprintf(buf, sizeof(buf), format, ap);
+  va_end(ap);
+  return buf;
+}
+
+bool benchmark_running = false;
+int64 benchmark_real_time_us = 0;
+int64 benchmark_cpu_time_us = 0;
+string *benchmark_label = NULL;
+int64 benchmark_bytes_processed = 0;
+
+void ResetBenchmarkTiming() {
+  benchmark_real_time_us = 0;
+  benchmark_cpu_time_us = 0;
+}
+
+#ifdef WIN32
+LARGE_INTEGER benchmark_start_real;
+FILETIME benchmark_start_cpu;
+#else  // WIN32
+struct timeval benchmark_start_real;
+struct rusage benchmark_start_cpu;
+#endif  // WIN32
+
+void StartBenchmarkTiming() {
+#ifdef WIN32
+  QueryPerformanceCounter(&benchmark_start_real);
+  FILETIME dummy;
+  CHECK(GetProcessTimes(
+      GetCurrentProcess(), &dummy, &dummy, &dummy, &benchmark_start_cpu));
+#else
+  gettimeofday(&benchmark_start_real, NULL);
+  if (getrusage(RUSAGE_SELF, &benchmark_start_cpu) == -1) {
+    perror("getrusage(RUSAGE_SELF)");
+    exit(1);
+  }
+#endif
+  benchmark_running = true;
+}
+
+void StopBenchmarkTiming() {
+  if (!benchmark_running) {
+    return;
+  }
+
+#ifdef WIN32
+  LARGE_INTEGER benchmark_stop_real;
+  LARGE_INTEGER benchmark_frequency;
+  QueryPerformanceCounter(&benchmark_stop_real);
+  QueryPerformanceFrequency(&benchmark_frequency);
+
+  double elapsed_real = static_cast<double>(
+      benchmark_stop_real.QuadPart - benchmark_start_real.QuadPart) /
+      benchmark_frequency.QuadPart;
+  benchmark_real_time_us += elapsed_real * 1e6 + 0.5;
+
+  FILETIME benchmark_stop_cpu, dummy;
+  CHECK(GetProcessTimes(
+      GetCurrentProcess(), &dummy, &dummy, &dummy, &benchmark_stop_cpu));
+
+  ULARGE_INTEGER start_ulargeint;
+  start_ulargeint.LowPart = benchmark_start_cpu.dwLowDateTime;
+  start_ulargeint.HighPart = benchmark_start_cpu.dwHighDateTime;
+
+  ULARGE_INTEGER stop_ulargeint;
+  stop_ulargeint.LowPart = benchmark_stop_cpu.dwLowDateTime;
+  stop_ulargeint.HighPart = benchmark_stop_cpu.dwHighDateTime;
+
+  benchmark_cpu_time_us +=
+      (stop_ulargeint.QuadPart - start_ulargeint.QuadPart + 5) / 10;
+#else  // WIN32
+  struct timeval benchmark_stop_real;
+  gettimeofday(&benchmark_stop_real, NULL);
+  benchmark_real_time_us +=
+      1000000 * (benchmark_stop_real.tv_sec - benchmark_start_real.tv_sec);
+  benchmark_real_time_us +=
+      (benchmark_stop_real.tv_usec - benchmark_start_real.tv_usec);
+
+  struct rusage benchmark_stop_cpu;
+  if (getrusage(RUSAGE_SELF, &benchmark_stop_cpu) == -1) {
+    perror("getrusage(RUSAGE_SELF)");
+    exit(1);
+  }
+  benchmark_cpu_time_us += 1000000 * (benchmark_stop_cpu.ru_utime.tv_sec -
+                                      benchmark_start_cpu.ru_utime.tv_sec);
+  benchmark_cpu_time_us += (benchmark_stop_cpu.ru_utime.tv_usec -
+                            benchmark_start_cpu.ru_utime.tv_usec);
+#endif  // WIN32
+
+  benchmark_running = false;
+}
+
+void SetBenchmarkLabel(const string& str) {
+  if (benchmark_label) {
+    delete benchmark_label;
+  }
+  benchmark_label = new string(str);
+}
+
+void SetBenchmarkBytesProcessed(int64 bytes) {
+  benchmark_bytes_processed = bytes;
+}
+
+struct BenchmarkRun {
+  int64 real_time_us;
+  int64 cpu_time_us;
+};
+
+struct BenchmarkCompareCPUTime {
+  bool operator() (const BenchmarkRun& a, const BenchmarkRun& b) const {
+    return a.cpu_time_us < b.cpu_time_us;
+  }
+};
+
+void Benchmark::Run() {
+  for (int test_case_num = start_; test_case_num <= stop_; ++test_case_num) {
+    // Run a few iterations first to find out approximately how fast
+    // the benchmark is.
+    const int kCalibrateIterations = 100;
+    ResetBenchmarkTiming();
+    StartBenchmarkTiming();
+    (*function_)(kCalibrateIterations, test_case_num);
+    StopBenchmarkTiming();
+
+    // Let each test case run for about 200ms, but at least as many
+    // as we used to calibrate.
+    // Run five times and pick the median.
+    const int kNumRuns = 5;
+    const int kMedianPos = kNumRuns / 2;
+    int num_iterations = 0;
+    if (benchmark_real_time_us > 0) {
+      num_iterations = 200000 * kCalibrateIterations / benchmark_real_time_us;
+    }
+    num_iterations = max(num_iterations, kCalibrateIterations);
+    BenchmarkRun benchmark_runs[kNumRuns];
+
+    for (int run = 0; run < kNumRuns; ++run) {
+      ResetBenchmarkTiming();
+      StartBenchmarkTiming();
+      (*function_)(num_iterations, test_case_num);
+      StopBenchmarkTiming();
+
+      benchmark_runs[run].real_time_us = benchmark_real_time_us;
+      benchmark_runs[run].cpu_time_us = benchmark_cpu_time_us;
+    }
+
+    string heading = StringPrintf("%s/%d", name_.c_str(), test_case_num);
+    string human_readable_speed;
+
+    nth_element(benchmark_runs,
+                benchmark_runs + kMedianPos,
+                benchmark_runs + kNumRuns,
+                BenchmarkCompareCPUTime());
+    int64 real_time_us = benchmark_runs[kMedianPos].real_time_us;
+    int64 cpu_time_us = benchmark_runs[kMedianPos].cpu_time_us;
+    if (cpu_time_us <= 0) {
+      human_readable_speed = "?";
+    } else {
+      int64 bytes_per_second =
+          benchmark_bytes_processed * 1000000 / cpu_time_us;
+      if (bytes_per_second < 1024) {
+        human_readable_speed = StringPrintf("%dB/s", bytes_per_second);
+      } else if (bytes_per_second < 1024 * 1024) {
+        human_readable_speed = StringPrintf(
+            "%.1fkB/s", bytes_per_second / 1024.0f);
+      } else if (bytes_per_second < 1024 * 1024 * 1024) {
+        human_readable_speed = StringPrintf(
+            "%.1fMB/s", bytes_per_second / (1024.0f * 1024.0f));
+      } else {
+        human_readable_speed = StringPrintf(
+            "%.1fGB/s", bytes_per_second / (1024.0f * 1024.0f * 1024.0f));
+      }
+    }
+
+    fprintf(stderr,
+#ifdef WIN32
+            "%-18s %10I64d %10I64d %10d %s  %s\n",
+#else
+            "%-18s %10lld %10lld %10d %s  %s\n",
+#endif
+            heading.c_str(),
+            static_cast<long long>(real_time_us * 1000 / num_iterations),
+            static_cast<long long>(cpu_time_us * 1000 / num_iterations),
+            num_iterations,
+            human_readable_speed.c_str(),
+            benchmark_label->c_str());
+  }
+}
+
+#ifdef HAVE_LIBZ
+
+ZLib::ZLib()
+    : comp_init_(false),
+      uncomp_init_(false) {
+  Reinit();
+}
+
+ZLib::~ZLib() {
+  if (comp_init_)   { deflateEnd(&comp_stream_); }
+  if (uncomp_init_) { inflateEnd(&uncomp_stream_); }
+}
+
+void ZLib::Reinit() {
+  compression_level_ = Z_DEFAULT_COMPRESSION;
+  window_bits_ = MAX_WBITS;
+  mem_level_ =  8;  // DEF_MEM_LEVEL
+  if (comp_init_) {
+    deflateEnd(&comp_stream_);
+    comp_init_ = false;
+  }
+  if (uncomp_init_) {
+    inflateEnd(&uncomp_stream_);
+    uncomp_init_ = false;
+  }
+  first_chunk_ = true;
+}
+
+void ZLib::Reset() {
+  first_chunk_ = true;
+}
+
+// --------- COMPRESS MODE
+
+// Initialization method to be called if we hit an error while
+// compressing. On hitting an error, call this method before returning
+// the error.
+void ZLib::CompressErrorInit() {
+  deflateEnd(&comp_stream_);
+  comp_init_ = false;
+  Reset();
+}
+
+int ZLib::DeflateInit() {
+  return deflateInit2(&comp_stream_,
+                      compression_level_,
+                      Z_DEFLATED,
+                      window_bits_,
+                      mem_level_,
+                      Z_DEFAULT_STRATEGY);
+}
+
+int ZLib::CompressInit(Bytef *dest, uLongf *destLen,
+                       const Bytef *source, uLong *sourceLen) {
+  int err;
+
+  comp_stream_.next_in = (Bytef*)source;
+  comp_stream_.avail_in = (uInt)*sourceLen;
+  if ((uLong)comp_stream_.avail_in != *sourceLen) return Z_BUF_ERROR;
+  comp_stream_.next_out = dest;
+  comp_stream_.avail_out = (uInt)*destLen;
+  if ((uLong)comp_stream_.avail_out != *destLen) return Z_BUF_ERROR;
+
+  if ( !first_chunk_ )   // only need to set up stream the first time through
+    return Z_OK;
+
+  if (comp_init_) {      // we've already initted it
+    err = deflateReset(&comp_stream_);
+    if (err != Z_OK) {
+      LOG(WARNING) << "ERROR: Can't reset compress object; creating a new one";
+      deflateEnd(&comp_stream_);
+      comp_init_ = false;
+    }
+  }
+  if (!comp_init_) {     // first use
+    comp_stream_.zalloc = (alloc_func)0;
+    comp_stream_.zfree = (free_func)0;
+    comp_stream_.opaque = (voidpf)0;
+    err = DeflateInit();
+    if (err != Z_OK) return err;
+    comp_init_ = true;
+  }
+  return Z_OK;
+}
+
+// In a perfect world we'd always have the full buffer to compress
+// when the time came, and we could just call Compress().  Alas, we
+// want to do chunked compression on our webserver.  In this
+// application, we compress the header, send it off, then compress the
+// results, send them off, then compress the footer.  Thus we need to
+// use the chunked compression features of zlib.
+int ZLib::CompressAtMostOrAll(Bytef *dest, uLongf *destLen,
+                              const Bytef *source, uLong *sourceLen,
+                              int flush_mode) {   // Z_FULL_FLUSH or Z_FINISH
+  int err;
+
+  if ( (err=CompressInit(dest, destLen, source, sourceLen)) != Z_OK )
+    return err;
+
+  // This is used to figure out how many bytes we wrote *this chunk*
+  int compressed_size = comp_stream_.total_out;
+
+  // Some setup happens only for the first chunk we compress in a run
+  if ( first_chunk_ ) {
+    first_chunk_ = false;
+  }
+
+  // flush_mode is Z_FINISH for all mode, Z_SYNC_FLUSH for incremental
+  // compression.
+  err = deflate(&comp_stream_, flush_mode);
+
+  *sourceLen = comp_stream_.avail_in;
+
+  if ((err == Z_STREAM_END || err == Z_OK)
+      && comp_stream_.avail_in == 0
+      && comp_stream_.avail_out != 0 ) {
+    // we processed everything ok and the output buffer was large enough.
+    ;
+  } else if (err == Z_STREAM_END && comp_stream_.avail_in > 0) {
+    return Z_BUF_ERROR;                            // should never happen
+  } else if (err != Z_OK && err != Z_STREAM_END && err != Z_BUF_ERROR) {
+    // an error happened
+    CompressErrorInit();
+    return err;
+  } else if (comp_stream_.avail_out == 0) {     // not enough space
+    err = Z_BUF_ERROR;
+  }
+
+  assert(err == Z_OK || err == Z_STREAM_END || err == Z_BUF_ERROR);
+  if (err == Z_STREAM_END)
+    err = Z_OK;
+
+  // update the crc and other metadata
+  compressed_size = comp_stream_.total_out - compressed_size;  // delta
+  *destLen = compressed_size;
+
+  return err;
+}
+
+int ZLib::CompressChunkOrAll(Bytef *dest, uLongf *destLen,
+                             const Bytef *source, uLong sourceLen,
+                             int flush_mode) {   // Z_FULL_FLUSH or Z_FINISH
+  const int ret =
+    CompressAtMostOrAll(dest, destLen, source, &sourceLen, flush_mode);
+  if (ret == Z_BUF_ERROR)
+    CompressErrorInit();
+  return ret;
+}
+
+// This routine only initializes the compression stream once.  Thereafter, it
+// just does a deflateReset on the stream, which should be faster.
+int ZLib::Compress(Bytef *dest, uLongf *destLen,
+                   const Bytef *source, uLong sourceLen) {
+  int err;
+  if ( (err=CompressChunkOrAll(dest, destLen, source, sourceLen,
+                               Z_FINISH)) != Z_OK )
+    return err;
+  Reset();         // reset for next call to Compress
+
+  return Z_OK;
+}
+
+
+// --------- UNCOMPRESS MODE
+
+int ZLib::InflateInit() {
+  return inflateInit2(&uncomp_stream_, MAX_WBITS);
+}
+
+// Initialization method to be called if we hit an error while
+// uncompressing. On hitting an error, call this method before
+// returning the error.
+void ZLib::UncompressErrorInit() {
+  inflateEnd(&uncomp_stream_);
+  uncomp_init_ = false;
+  Reset();
+}
+
+int ZLib::UncompressInit(Bytef *dest, uLongf *destLen,
+                         const Bytef *source, uLong *sourceLen) {
+  int err;
+
+  uncomp_stream_.next_in = (Bytef*)source;
+  uncomp_stream_.avail_in = (uInt)*sourceLen;
+  // Check for source > 64K on 16-bit machine:
+  if ((uLong)uncomp_stream_.avail_in != *sourceLen) return Z_BUF_ERROR;
+
+  uncomp_stream_.next_out = dest;
+  uncomp_stream_.avail_out = (uInt)*destLen;
+  if ((uLong)uncomp_stream_.avail_out != *destLen) return Z_BUF_ERROR;
+
+  if ( !first_chunk_ )   // only need to set up stream the first time through
+    return Z_OK;
+
+  if (uncomp_init_) {    // we've already initted it
+    err = inflateReset(&uncomp_stream_);
+    if (err != Z_OK) {
+      LOG(WARNING)
+        << "ERROR: Can't reset uncompress object; creating a new one";
+      UncompressErrorInit();
+    }
+  }
+  if (!uncomp_init_) {
+    uncomp_stream_.zalloc = (alloc_func)0;
+    uncomp_stream_.zfree = (free_func)0;
+    uncomp_stream_.opaque = (voidpf)0;
+    err = InflateInit();
+    if (err != Z_OK) return err;
+    uncomp_init_ = true;
+  }
+  return Z_OK;
+}
+
+// If you compressed your data a chunk at a time, with CompressChunk,
+// you can uncompress it a chunk at a time with UncompressChunk.
+// Only difference bewteen chunked and unchunked uncompression
+// is the flush mode we use: Z_SYNC_FLUSH (chunked) or Z_FINISH (unchunked).
+int ZLib::UncompressAtMostOrAll(Bytef *dest, uLongf *destLen,
+                                const Bytef *source, uLong *sourceLen,
+                                int flush_mode) {  // Z_SYNC_FLUSH or Z_FINISH
+  int err = Z_OK;
+
+  if ( (err=UncompressInit(dest, destLen, source, sourceLen)) != Z_OK ) {
+    LOG(WARNING) << "UncompressInit: Error: " << err << " SourceLen: "
+                 << *sourceLen;
+    return err;
+  }
+
+  // This is used to figure out how many output bytes we wrote *this chunk*:
+  const uLong old_total_out = uncomp_stream_.total_out;
+
+  // This is used to figure out how many input bytes we read *this chunk*:
+  const uLong old_total_in = uncomp_stream_.total_in;
+
+  // Some setup happens only for the first chunk we compress in a run
+  if ( first_chunk_ ) {
+    first_chunk_ = false;                          // so we don't do this again
+
+    // For the first chunk *only* (to avoid infinite troubles), we let
+    // there be no actual data to uncompress.  This sometimes triggers
+    // when the input is only the gzip header, say.
+    if ( *sourceLen == 0 ) {
+      *destLen = 0;
+      return Z_OK;
+    }
+  }
+
+  // We'll uncompress as much as we can.  If we end OK great, otherwise
+  // if we get an error that seems to be the gzip footer, we store the
+  // gzip footer and return OK, otherwise we return the error.
+
+  // flush_mode is Z_SYNC_FLUSH for chunked mode, Z_FINISH for all mode.
+  err = inflate(&uncomp_stream_, flush_mode);
+
+  // Figure out how many bytes of the input zlib slurped up:
+  const uLong bytes_read = uncomp_stream_.total_in - old_total_in;
+  CHECK_LE(source + bytes_read, source + *sourceLen);
+  *sourceLen = uncomp_stream_.avail_in;
+
+  if ((err == Z_STREAM_END || err == Z_OK)  // everything went ok
+             && uncomp_stream_.avail_in == 0) {    // and we read it all
+    ;
+  } else if (err == Z_STREAM_END && uncomp_stream_.avail_in > 0) {
+    LOG(WARNING)
+      << "UncompressChunkOrAll: Received some extra data, bytes total: "
+      << uncomp_stream_.avail_in << " bytes: "
+      << string(reinterpret_cast<const char *>(uncomp_stream_.next_in),
+                min(int(uncomp_stream_.avail_in), 20));
+    UncompressErrorInit();
+    return Z_DATA_ERROR;       // what's the extra data for?
+  } else if (err != Z_OK && err != Z_STREAM_END && err != Z_BUF_ERROR) {
+    // an error happened
+    LOG(WARNING) << "UncompressChunkOrAll: Error: " << err
+                 << " avail_out: " << uncomp_stream_.avail_out;
+    UncompressErrorInit();
+    return err;
+  } else if (uncomp_stream_.avail_out == 0) {
+    err = Z_BUF_ERROR;
+  }
+
+  assert(err == Z_OK || err == Z_BUF_ERROR || err == Z_STREAM_END);
+  if (err == Z_STREAM_END)
+    err = Z_OK;
+
+  *destLen = uncomp_stream_.total_out - old_total_out;  // size for this call
+
+  return err;
+}
+
+int ZLib::UncompressChunkOrAll(Bytef *dest, uLongf *destLen,
+                               const Bytef *source, uLong sourceLen,
+                               int flush_mode) {  // Z_SYNC_FLUSH or Z_FINISH
+  const int ret =
+    UncompressAtMostOrAll(dest, destLen, source, &sourceLen, flush_mode);
+  if (ret == Z_BUF_ERROR)
+    UncompressErrorInit();
+  return ret;
+}
+
+int ZLib::UncompressAtMost(Bytef *dest, uLongf *destLen,
+                          const Bytef *source, uLong *sourceLen) {
+  return UncompressAtMostOrAll(dest, destLen, source, sourceLen, Z_SYNC_FLUSH);
+}
+
+// We make sure we've uncompressed everything, that is, the current
+// uncompress stream is at a compressed-buffer-EOF boundary.  In gzip
+// mode, we also check the gzip footer to make sure we pass the gzip
+// consistency checks.  We RETURN true iff both types of checks pass.
+bool ZLib::UncompressChunkDone() {
+  assert(!first_chunk_ && uncomp_init_);
+  // Make sure we're at the end-of-compressed-data point.  This means
+  // if we call inflate with Z_FINISH we won't consume any input or
+  // write any output
+  Bytef dummyin, dummyout;
+  uLongf dummylen = 0;
+  if ( UncompressChunkOrAll(&dummyout, &dummylen, &dummyin, 0, Z_FINISH)
+       != Z_OK ) {
+    return false;
+  }
+
+  // Make sure that when we exit, we can start a new round of chunks later
+  Reset();
+
+  return true;
+}
+
+// Uncompresses the source buffer into the destination buffer.
+// The destination buffer must be long enough to hold the entire
+// decompressed contents.
+//
+// We only initialize the uncomp_stream once.  Thereafter, we use
+// inflateReset, which should be faster.
+//
+// Returns Z_OK on success, otherwise, it returns a zlib error code.
+int ZLib::Uncompress(Bytef *dest, uLongf *destLen,
+                     const Bytef *source, uLong sourceLen) {
+  int err;
+  if ( (err=UncompressChunkOrAll(dest, destLen, source, sourceLen,
+                                 Z_FINISH)) != Z_OK ) {
+    Reset();                           // let us try to compress again
+    return err;
+  }
+  if ( !UncompressChunkDone() )        // calls Reset()
+    return Z_DATA_ERROR;
+  return Z_OK;  // stream_end is ok
+}
+
+#endif  // HAVE_LIBZ
+
+}  // namespace snappy
diff --git a/snappy/snappy-test.h b/snappy/snappy-test.h
new file mode 100644
index 00000000..f7ba79ed
--- /dev/null
+++ b/snappy/snappy-test.h
@@ -0,0 +1,580 @@
+// Copyright 2011 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// Various stubs for the unit tests for the open-source version of Snappy.
+
+#ifndef UTIL_SNAPPY_OPENSOURCE_SNAPPY_TEST_H_
+#define UTIL_SNAPPY_OPENSOURCE_SNAPPY_TEST_H_
+
+#include <iostream>
+#include <string>
+
+#include "snappy-stubs-internal.h"
+
+#include <stdio.h>
+#include <stdarg.h>
+
+#ifdef HAVE_SYS_MMAN_H
+#include <sys/mman.h>
+#endif
+
+#ifdef HAVE_SYS_RESOURCE_H
+#include <sys/resource.h>
+#endif
+
+#ifdef HAVE_SYS_TIME_H
+#include <sys/time.h>
+#endif
+
+#ifdef HAVE_WINDOWS_H
+#define WIN32_LEAN_AND_MEAN
+#include <windows.h>
+#endif
+
+#include <string>
+
+#ifdef HAVE_GTEST
+
+#include <gtest/gtest.h>
+#undef TYPED_TEST
+#define TYPED_TEST TEST
+#define INIT_GTEST(argc, argv) ::testing::InitGoogleTest(argc, *argv)
+
+#else
+
+// Stubs for if the user doesn't have Google Test installed.
+
+#define TEST(test_case, test_subcase) \
+  void Test_ ## test_case ## _ ## test_subcase()
+#define INIT_GTEST(argc, argv)
+
+#define TYPED_TEST TEST
+#define EXPECT_EQ CHECK_EQ
+#define EXPECT_NE CHECK_NE
+#define EXPECT_FALSE(cond) CHECK(!(cond))
+
+#endif
+
+#ifdef HAVE_GFLAGS
+
+#include <gflags/gflags.h>
+
+// This is tricky; both gflags and Google Test want to look at the command line
+// arguments. Google Test seems to be the most happy with unknown arguments,
+// though, so we call it first and hope for the best.
+#define InitGoogle(argv0, argc, argv, remove_flags) \
+  INIT_GTEST(argc, argv); \
+  google::ParseCommandLineFlags(argc, argv, remove_flags);
+
+#else
+
+// If we don't have the gflags package installed, these can only be
+// changed at compile time.
+#define DEFINE_int32(flag_name, default_value, description) \
+  static int FLAGS_ ## flag_name = default_value;
+
+#define InitGoogle(argv0, argc, argv, remove_flags) \
+  INIT_GTEST(argc, argv)
+
+#endif
+
+#ifdef HAVE_LIBZ
+#include "zlib.h"
+#endif
+
+#ifdef HAVE_LIBLZO2
+#include "lzo/lzo1x.h"
+#endif
+
+#ifdef HAVE_LIBLZF
+extern "C" {
+#include "lzf.h"
+}
+#endif
+
+#ifdef HAVE_LIBFASTLZ
+#include "fastlz.h"
+#endif
+
+#ifdef HAVE_LIBQUICKLZ
+#include "quicklz.h"
+#endif
+
+namespace {
+
+namespace File {
+  void Init() { }
+}  // namespace File
+
+namespace file {
+  int Defaults() { }
+
+  class DummyStatus {
+   public:
+    void CheckSuccess() { }
+  };
+
+  DummyStatus GetContents(const string& filename, string* data, int unused) {
+    FILE* fp = fopen(filename.c_str(), "rb");
+    if (fp == NULL) {
+      perror(filename.c_str());
+      exit(1);
+    }
+
+    data->clear();
+    while (!feof(fp)) {
+      char buf[4096];
+      size_t ret = fread(buf, 1, 4096, fp);
+      if (ret == 0 && ferror(fp)) {
+        perror("fread");
+        exit(1);
+      }
+      data->append(string(buf, ret));
+    }
+
+    fclose(fp);
+  }
+
+  DummyStatus SetContents(const string& filename,
+                          const string& str,
+                          int unused) {
+    FILE* fp = fopen(filename.c_str(), "wb");
+    if (fp == NULL) {
+      perror(filename.c_str());
+      exit(1);
+    }
+
+    int ret = fwrite(str.data(), str.size(), 1, fp);
+    if (ret != 1) {
+      perror("fwrite");
+      exit(1);
+    }
+
+    fclose(fp);
+  }
+}  // namespace file
+
+}  // namespace
+
+namespace snappy {
+
+#define FLAGS_test_random_seed 301
+typedef string TypeParam;
+
+void Test_CorruptedTest_VerifyCorrupted();
+void Test_Snappy_SimpleTests();
+void Test_Snappy_MaxBlowup();
+void Test_Snappy_RandomData();
+void Test_Snappy_FourByteOffset();
+void Test_SnappyCorruption_TruncatedVarint();
+void Test_SnappyCorruption_UnterminatedVarint();
+void Test_Snappy_ReadPastEndOfBuffer();
+void Test_Snappy_FindMatchLength();
+void Test_Snappy_FindMatchLengthRandom();
+
+string ReadTestDataFile(const string& base, size_t size_limit);
+
+string ReadTestDataFile(const string& base);
+
+// A sprintf() variant that returns a std::string.
+// Not safe for general use due to truncation issues.
+string StringPrintf(const char* format, ...);
+
+// A simple, non-cryptographically-secure random generator.
+class ACMRandom {
+ public:
+  explicit ACMRandom(uint32 seed) : seed_(seed) {}
+
+  int32 Next();
+
+  int32 Uniform(int32 n) {
+    return Next() % n;
+  }
+  uint8 Rand8() {
+    return static_cast<uint8>((Next() >> 1) & 0x000000ff);
+  }
+  bool OneIn(int X) { return Uniform(X) == 0; }
+
+  // Skewed: pick "base" uniformly from range [0,max_log] and then
+  // return "base" random bits.  The effect is to pick a number in the
+  // range [0,2^max_log-1] with bias towards smaller numbers.
+  int32 Skewed(int max_log);
+
+ private:
+  static const uint32 M = 2147483647L;   // 2^31-1
+  uint32 seed_;
+};
+
+inline int32 ACMRandom::Next() {
+  static const uint64 A = 16807;  // bits 14, 8, 7, 5, 2, 1, 0
+  // We are computing
+  //       seed_ = (seed_ * A) % M,    where M = 2^31-1
+  //
+  // seed_ must not be zero or M, or else all subsequent computed values
+  // will be zero or M respectively.  For all other values, seed_ will end
+  // up cycling through every number in [1,M-1]
+  uint64 product = seed_ * A;
+
+  // Compute (product % M) using the fact that ((x << 31) % M) == x.
+  seed_ = (product >> 31) + (product & M);
+  // The first reduction may overflow by 1 bit, so we may need to repeat.
+  // mod == M is not possible; using > allows the faster sign-bit-based test.
+  if (seed_ > M) {
+    seed_ -= M;
+  }
+  return seed_;
+}
+
+inline int32 ACMRandom::Skewed(int max_log) {
+  const int32 base = (Next() - 1) % (max_log+1);
+  return (Next() - 1) & ((1u << base)-1);
+}
+
+// A wall-time clock. This stub is not super-accurate, nor resistant to the
+// system time changing.
+class CycleTimer {
+ public:
+  CycleTimer() : real_time_us_(0) {}
+
+  void Start() {
+#ifdef WIN32
+    QueryPerformanceCounter(&start_);
+#else
+    gettimeofday(&start_, NULL);
+#endif
+  }
+
+  void Stop() {
+#ifdef WIN32
+    LARGE_INTEGER stop;
+    LARGE_INTEGER frequency;
+    QueryPerformanceCounter(&stop);
+    QueryPerformanceFrequency(&frequency);
+
+    double elapsed = static_cast<double>(stop.QuadPart - start_.QuadPart) /
+        frequency.QuadPart;
+    real_time_us_ += elapsed * 1e6 + 0.5;
+#else
+    struct timeval stop;
+    gettimeofday(&stop, NULL);
+
+    real_time_us_ += 1000000 * (stop.tv_sec - start_.tv_sec);
+    real_time_us_ += (stop.tv_usec - start_.tv_usec);
+#endif
+  }
+
+  double Get() {
+    return real_time_us_ * 1e-6;
+  }
+
+ private:
+  int64 real_time_us_;
+#ifdef WIN32
+  LARGE_INTEGER start_;
+#else
+  struct timeval start_;
+#endif
+};
+
+// Minimalistic microbenchmark framework.
+
+typedef void (*BenchmarkFunction)(int, int);
+
+class Benchmark {
+ public:
+  Benchmark(const string& name, BenchmarkFunction function) :
+      name_(name), function_(function) {}
+
+  Benchmark* DenseRange(int start, int stop) {
+    start_ = start;
+    stop_ = stop;
+    return this;
+  }
+
+  void Run();
+
+ private:
+  const string name_;
+  const BenchmarkFunction function_;
+  int start_, stop_;
+};
+#define BENCHMARK(benchmark_name) \
+  Benchmark* Benchmark_ ## benchmark_name = \
+          (new Benchmark(#benchmark_name, benchmark_name))
+
+extern Benchmark* Benchmark_BM_UFlat;
+extern Benchmark* Benchmark_BM_UValidate;
+extern Benchmark* Benchmark_BM_ZFlat;
+
+void ResetBenchmarkTiming();
+void StartBenchmarkTiming();
+void StopBenchmarkTiming();
+void SetBenchmarkLabel(const string& str);
+void SetBenchmarkBytesProcessed(int64 bytes);
+
+#ifdef HAVE_LIBZ
+
+// Object-oriented wrapper around zlib.
+class ZLib {
+ public:
+  ZLib();
+  ~ZLib();
+
+  // Wipe a ZLib object to a virgin state.  This differs from Reset()
+  // in that it also breaks any state.
+  void Reinit();
+
+  // Call this to make a zlib buffer as good as new.  Here's the only
+  // case where they differ:
+  //    CompressChunk(a); CompressChunk(b); CompressChunkDone();   vs
+  //    CompressChunk(a); Reset(); CompressChunk(b); CompressChunkDone();
+  // You'll want to use Reset(), then, when you interrupt a compress
+  // (or uncompress) in the middle of a chunk and want to start over.
+  void Reset();
+
+  // According to the zlib manual, when you Compress, the destination
+  // buffer must have size at least src + .1%*src + 12.  This function
+  // helps you calculate that.  Augment this to account for a potential
+  // gzip header and footer, plus a few bytes of slack.
+  static int MinCompressbufSize(int uncompress_size) {
+    return uncompress_size + uncompress_size/1000 + 40;
+  }
+
+  // Compresses the source buffer into the destination buffer.
+  // sourceLen is the byte length of the source buffer.
+  // Upon entry, destLen is the total size of the destination buffer,
+  // which must be of size at least MinCompressbufSize(sourceLen).
+  // Upon exit, destLen is the actual size of the compressed buffer.
+  //
+  // This function can be used to compress a whole file at once if the
+  // input file is mmap'ed.
+  //
+  // Returns Z_OK if success, Z_MEM_ERROR if there was not
+  // enough memory, Z_BUF_ERROR if there was not enough room in the
+  // output buffer. Note that if the output buffer is exactly the same
+  // size as the compressed result, we still return Z_BUF_ERROR.
+  // (check CL#1936076)
+  int Compress(Bytef *dest, uLongf *destLen,
+               const Bytef *source, uLong sourceLen);
+
+  // Uncompresses the source buffer into the destination buffer.
+  // The destination buffer must be long enough to hold the entire
+  // decompressed contents.
+  //
+  // Returns Z_OK on success, otherwise, it returns a zlib error code.
+  int Uncompress(Bytef *dest, uLongf *destLen,
+                 const Bytef *source, uLong sourceLen);
+
+  // Uncompress data one chunk at a time -- ie you can call this
+  // more than once.  To get this to work you need to call per-chunk
+  // and "done" routines.
+  //
+  // Returns Z_OK if success, Z_MEM_ERROR if there was not
+  // enough memory, Z_BUF_ERROR if there was not enough room in the
+  // output buffer.
+
+  int UncompressAtMost(Bytef *dest, uLongf *destLen,
+                       const Bytef *source, uLong *sourceLen);
+
+  // Checks gzip footer information, as needed.  Mostly this just
+  // makes sure the checksums match.  Whenever you call this, it
+  // will assume the last 8 bytes from the previous UncompressChunk
+  // call are the footer.  Returns true iff everything looks ok.
+  bool UncompressChunkDone();
+
+ private:
+  int InflateInit();       // sets up the zlib inflate structure
+  int DeflateInit();       // sets up the zlib deflate structure
+
+  // These init the zlib data structures for compressing/uncompressing
+  int CompressInit(Bytef *dest, uLongf *destLen,
+                   const Bytef *source, uLong *sourceLen);
+  int UncompressInit(Bytef *dest, uLongf *destLen,
+                     const Bytef *source, uLong *sourceLen);
+  // Initialization method to be called if we hit an error while
+  // uncompressing. On hitting an error, call this method before
+  // returning the error.
+  void UncompressErrorInit();
+
+  // Helper function for Compress
+  int CompressChunkOrAll(Bytef *dest, uLongf *destLen,
+                         const Bytef *source, uLong sourceLen,
+                         int flush_mode);
+  int CompressAtMostOrAll(Bytef *dest, uLongf *destLen,
+                          const Bytef *source, uLong *sourceLen,
+                          int flush_mode);
+
+  // Likewise for UncompressAndUncompressChunk
+  int UncompressChunkOrAll(Bytef *dest, uLongf *destLen,
+                           const Bytef *source, uLong sourceLen,
+                           int flush_mode);
+
+  int UncompressAtMostOrAll(Bytef *dest, uLongf *destLen,
+                            const Bytef *source, uLong *sourceLen,
+                            int flush_mode);
+
+  // Initialization method to be called if we hit an error while
+  // compressing. On hitting an error, call this method before
+  // returning the error.
+  void CompressErrorInit();
+
+  int compression_level_;   // compression level
+  int window_bits_;         // log base 2 of the window size used in compression
+  int mem_level_;           // specifies the amount of memory to be used by
+                            // compressor (1-9)
+  z_stream comp_stream_;    // Zlib stream data structure
+  bool comp_init_;          // True if we have initialized comp_stream_
+  z_stream uncomp_stream_;  // Zlib stream data structure
+  bool uncomp_init_;        // True if we have initialized uncomp_stream_
+
+  // These are used only with chunked compression.
+  bool first_chunk_;       // true if we need to emit headers with this chunk
+};
+
+#endif  // HAVE_LIBZ
+
+}  // namespace snappy
+
+DECLARE_bool(run_microbenchmarks);
+
+static void RunSpecifiedBenchmarks() {
+  if (!FLAGS_run_microbenchmarks) {
+    return;
+  }
+
+  fprintf(stderr, "Running microbenchmarks.\n");
+#ifndef NDEBUG
+  fprintf(stderr, "WARNING: Compiled with assertions enabled, will be slow.\n");
+#endif
+#ifndef __OPTIMIZE__
+  fprintf(stderr, "WARNING: Compiled without optimization, will be slow.\n");
+#endif
+  fprintf(stderr, "Benchmark            Time(ns)    CPU(ns) Iterations\n");
+  fprintf(stderr, "---------------------------------------------------\n");
+
+  snappy::Benchmark_BM_UFlat->Run();
+  snappy::Benchmark_BM_UValidate->Run();
+  snappy::Benchmark_BM_ZFlat->Run();
+
+  fprintf(stderr, "\n");
+}
+
+#ifndef HAVE_GTEST
+
+static inline int RUN_ALL_TESTS() {
+  fprintf(stderr, "Running correctness tests.\n");
+  snappy::Test_CorruptedTest_VerifyCorrupted();
+  snappy::Test_Snappy_SimpleTests();
+  snappy::Test_Snappy_MaxBlowup();
+  snappy::Test_Snappy_RandomData();
+  snappy::Test_Snappy_FourByteOffset();
+  snappy::Test_SnappyCorruption_TruncatedVarint();
+  snappy::Test_SnappyCorruption_UnterminatedVarint();
+  snappy::Test_Snappy_ReadPastEndOfBuffer();
+  snappy::Test_Snappy_FindMatchLength();
+  snappy::Test_Snappy_FindMatchLengthRandom();
+  fprintf(stderr, "All tests passed.\n");
+
+  return 0;
+}
+
+#endif  // HAVE_GTEST
+
+// For main().
+namespace snappy {
+
+static void CompressFile(const char* fname);
+static void UncompressFile(const char* fname);
+static void MeasureFile(const char* fname);
+
+// Logging.
+
+#define LOG(level) LogMessage()
+#define VLOG(level) true ? (void)0 : \
+    snappy::LogMessageVoidify() & snappy::LogMessage()
+
+class LogMessage {
+ public:
+  LogMessage() { }
+  ~LogMessage() {
+    cerr << endl;
+  }
+
+  LogMessage& operator<<(const std::string& msg) {
+    cerr << msg;
+    return *this;
+  }
+  LogMessage& operator<<(int x) {
+    cerr << x;
+    return *this;
+  }
+};
+
+// Asserts, both versions activated in debug mode only,
+// and ones that are always active.
+
+#define CRASH_UNLESS(condition) \
+    PREDICT_TRUE(condition) ? (void)0 : \
+    snappy::LogMessageVoidify() & snappy::LogMessageCrash()
+
+class LogMessageCrash : public LogMessage {
+ public:
+  LogMessageCrash() { }
+  ~LogMessageCrash() {
+    cerr << endl;
+    abort();
+  }
+};
+
+// This class is used to explicitly ignore values in the conditional
+// logging macros.  This avoids compiler warnings like "value computed
+// is not used" and "statement has no effect".
+
+class LogMessageVoidify {
+ public:
+  LogMessageVoidify() { }
+  // This has to be an operator with a precedence lower than << but
+  // higher than ?:
+  void operator&(const LogMessage&) { }
+};
+
+#define CHECK(cond) CRASH_UNLESS(cond)
+#define CHECK_LE(a, b) CRASH_UNLESS((a) <= (b))
+#define CHECK_GE(a, b) CRASH_UNLESS((a) >= (b))
+#define CHECK_EQ(a, b) CRASH_UNLESS((a) == (b))
+#define CHECK_NE(a, b) CRASH_UNLESS((a) != (b))
+#define CHECK_LT(a, b) CRASH_UNLESS((a) < (b))
+#define CHECK_GT(a, b) CRASH_UNLESS((a) > (b))
+
+}  // namespace
+
+using snappy::CompressFile;
+using snappy::UncompressFile;
+using snappy::MeasureFile;
+
+#endif  // UTIL_SNAPPY_OPENSOURCE_SNAPPY_TEST_H_
diff --git a/snappy/snappy.cc b/snappy/snappy.cc
new file mode 100644
index 00000000..1230321f
--- /dev/null
+++ b/snappy/snappy.cc
@@ -0,0 +1,1119 @@
+// Copyright 2005 Google Inc. All Rights Reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "snappy.h"
+#include "snappy-internal.h"
+#include "snappy-sinksource.h"
+
+#include <stdio.h>
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+
+namespace snappy {
+
+// Any hash function will produce a valid compressed bitstream, but a good
+// hash function reduces the number of collisions and thus yields better
+// compression for compressible input, and more speed for incompressible
+// input. Of course, it doesn't hurt if the hash function is reasonably fast
+// either, as it gets called a lot.
+static inline uint32 HashBytes(uint32 bytes, int shift) {
+  uint32 kMul = 0x1e35a7bd;
+  return (bytes * kMul) >> shift;
+}
+static inline uint32 Hash(const char* p, int shift) {
+  return HashBytes(UNALIGNED_LOAD32(p), shift);
+}
+
+size_t MaxCompressedLength(size_t source_len) {
+  // Compressed data can be defined as:
+  //    compressed := item* literal*
+  //    item       := literal* copy
+  //
+  // The trailing literal sequence has a space blowup of at most 62/60
+  // since a literal of length 60 needs one tag byte + one extra byte
+  // for length information.
+  //
+  // Item blowup is trickier to measure.  Suppose the "copy" op copies
+  // 4 bytes of data.  Because of a special check in the encoding code,
+  // we produce a 4-byte copy only if the offset is < 65536.  Therefore
+  // the copy op takes 3 bytes to encode, and this type of item leads
+  // to at most the 62/60 blowup for representing literals.
+  //
+  // Suppose the "copy" op copies 5 bytes of data.  If the offset is big
+  // enough, it will take 5 bytes to encode the copy op.  Therefore the
+  // worst case here is a one-byte literal followed by a five-byte copy.
+  // I.e., 6 bytes of input turn into 7 bytes of "compressed" data.
+  //
+  // This last factor dominates the blowup, so the final estimate is:
+  return 32 + source_len + source_len/6;
+}
+
+enum {
+  LITERAL = 0,
+  COPY_1_BYTE_OFFSET = 1,  // 3 bit length + 3 bits of offset in opcode
+  COPY_2_BYTE_OFFSET = 2,
+  COPY_4_BYTE_OFFSET = 3
+};
+
+// Copy "len" bytes from "src" to "op", one byte at a time.  Used for
+// handling COPY operations where the input and output regions may
+// overlap.  For example, suppose:
+//    src    == "ab"
+//    op     == src + 2
+//    len    == 20
+// After IncrementalCopy(src, op, len), the result will have
+// eleven copies of "ab"
+//    ababababababababababab
+// Note that this does not match the semantics of either memcpy()
+// or memmove().
+static inline void IncrementalCopy(const char* src, char* op, int len) {
+  assert(len > 0);
+  do {
+    *op++ = *src++;
+  } while (--len > 0);
+}
+
+// Equivalent to IncrementalCopy except that it can write up to ten extra
+// bytes after the end of the copy, and that it is faster.
+//
+// The main part of this loop is a simple copy of eight bytes at a time until
+// we've copied (at least) the requested amount of bytes.  However, if op and
+// src are less than eight bytes apart (indicating a repeating pattern of
+// length < 8), we first need to expand the pattern in order to get the correct
+// results. For instance, if the buffer looks like this, with the eight-byte
+// <src> and <op> patterns marked as intervals:
+//
+//    abxxxxxxxxxxxx
+//    [------]           src
+//      [------]         op
+//
+// a single eight-byte copy from <src> to <op> will repeat the pattern once,
+// after which we can move <op> two bytes without moving <src>:
+//
+//    ababxxxxxxxxxx
+//    [------]           src
+//        [------]       op
+//
+// and repeat the exercise until the two no longer overlap.
+//
+// This allows us to do very well in the special case of one single byte
+// repeated many times, without taking a big hit for more general cases.
+//
+// The worst case of extra writing past the end of the match occurs when
+// op - src == 1 and len == 1; the last copy will read from byte positions
+// [0..7] and write to [4..11], whereas it was only supposed to write to
+// position 1. Thus, ten excess bytes.
+
+namespace {
+
+const int kMaxIncrementCopyOverflow = 10;
+
+}  // namespace
+
+static inline void IncrementalCopyFastPath(const char* src, char* op, int len) {
+  while (op - src < 8) {
+    UnalignedCopy64(src, op);
+    len -= op - src;
+    op += op - src;
+  }
+  while (len > 0) {
+    UnalignedCopy64(src, op);
+    src += 8;
+    op += 8;
+    len -= 8;
+  }
+}
+
+static inline char* EmitLiteral(char* op,
+                                const char* literal,
+                                int len,
+                                bool allow_fast_path) {
+  int n = len - 1;      // Zero-length literals are disallowed
+  if (n < 60) {
+    // Fits in tag byte
+    *op++ = LITERAL | (n << 2);
+
+    // The vast majority of copies are below 16 bytes, for which a
+    // call to memcpy is overkill. This fast path can sometimes
+    // copy up to 15 bytes too much, but that is okay in the
+    // main loop, since we have a bit to go on for both sides:
+    //
+    //   - The input will always have kInputMarginBytes = 15 extra
+    //     available bytes, as long as we're in the main loop, and
+    //     if not, allow_fast_path = false.
+    //   - The output will always have 32 spare bytes (see
+    //     MaxCompressedLength).
+    if (allow_fast_path && len <= 16) {
+      UnalignedCopy64(literal, op);
+      UnalignedCopy64(literal + 8, op + 8);
+      return op + len;
+    }
+  } else {
+    // Encode in upcoming bytes
+    char* base = op;
+    int count = 0;
+    op++;
+    while (n > 0) {
+      *op++ = n & 0xff;
+      n >>= 8;
+      count++;
+    }
+    assert(count >= 1);
+    assert(count <= 4);
+    *base = LITERAL | ((59+count) << 2);
+  }
+  memcpy(op, literal, len);
+  return op + len;
+}
+
+static inline char* EmitCopyLessThan64(char* op, size_t offset, int len) {
+  assert(len <= 64);
+  assert(len >= 4);
+  assert(offset < 65536);
+
+  if ((len < 12) && (offset < 2048)) {
+    size_t len_minus_4 = len - 4;
+    assert(len_minus_4 < 8);            // Must fit in 3 bits
+    *op++ = COPY_1_BYTE_OFFSET + ((len_minus_4) << 2) + ((offset >> 8) << 5);
+    *op++ = offset & 0xff;
+  } else {
+    *op++ = COPY_2_BYTE_OFFSET + ((len-1) << 2);
+    LittleEndian::Store16(op, offset);
+    op += 2;
+  }
+  return op;
+}
+
+static inline char* EmitCopy(char* op, size_t offset, int len) {
+  // Emit 64 byte copies but make sure to keep at least four bytes reserved
+  while (len >= 68) {
+    op = EmitCopyLessThan64(op, offset, 64);
+    len -= 64;
+  }
+
+  // Emit an extra 60 byte copy if have too much data to fit in one copy
+  if (len > 64) {
+    op = EmitCopyLessThan64(op, offset, 60);
+    len -= 60;
+  }
+
+  // Emit remainder
+  op = EmitCopyLessThan64(op, offset, len);
+  return op;
+}
+
+
+bool GetUncompressedLength(const char* start, size_t n, size_t* result) {
+  uint32 v = 0;
+  const char* limit = start + n;
+  if (Varint::Parse32WithLimit(start, limit, &v) != NULL) {
+    *result = v;
+    return true;
+  } else {
+    return false;
+  }
+}
+
+namespace internal {
+uint16* WorkingMemory::GetHashTable(size_t input_size, int* table_size) {
+  // Use smaller hash table when input.size() is smaller, since we
+  // fill the table, incurring O(hash table size) overhead for
+  // compression, and if the input is short, we won't need that
+  // many hash table entries anyway.
+  assert(kMaxHashTableSize >= 256);
+  size_t htsize = 256;
+  while (htsize < kMaxHashTableSize && htsize < input_size) {
+    htsize <<= 1;
+  }
+
+  uint16* table;
+  if (htsize <= ARRAYSIZE(small_table_)) {
+    table = small_table_;
+  } else {
+    if (large_table_ == NULL) {
+      large_table_ = new uint16[kMaxHashTableSize];
+    }
+    table = large_table_;
+  }
+
+  *table_size = htsize;
+  memset(table, 0, htsize * sizeof(*table));
+  return table;
+}
+}  // end namespace internal
+
+// For 0 <= offset <= 4, GetUint32AtOffset(GetEightBytesAt(p), offset) will
+// equal UNALIGNED_LOAD32(p + offset).  Motivation: On x86-64 hardware we have
+// empirically found that overlapping loads such as
+//  UNALIGNED_LOAD32(p) ... UNALIGNED_LOAD32(p+1) ... UNALIGNED_LOAD32(p+2)
+// are slower than UNALIGNED_LOAD64(p) followed by shifts and casts to uint32.
+//
+// We have different versions for 64- and 32-bit; ideally we would avoid the
+// two functions and just inline the UNALIGNED_LOAD64 call into
+// GetUint32AtOffset, but GCC (at least not as of 4.6) is seemingly not clever
+// enough to avoid loading the value multiple times then. For 64-bit, the load
+// is done when GetEightBytesAt() is called, whereas for 32-bit, the load is
+// done at GetUint32AtOffset() time.
+
+#ifdef ARCH_K8
+
+typedef uint64 EightBytesReference;
+
+static inline EightBytesReference GetEightBytesAt(const char* ptr) {
+  return UNALIGNED_LOAD64(ptr);
+}
+
+static inline uint32 GetUint32AtOffset(uint64 v, int offset) {
+  assert(offset >= 0);
+  assert(offset <= 4);
+  return v >> (LittleEndian::IsLittleEndian() ? 8 * offset : 32 - 8 * offset);
+}
+
+#else
+
+typedef const char* EightBytesReference;
+
+static inline EightBytesReference GetEightBytesAt(const char* ptr) {
+  return ptr;
+}
+
+static inline uint32 GetUint32AtOffset(const char* v, int offset) {
+  assert(offset >= 0);
+  assert(offset <= 4);
+  return UNALIGNED_LOAD32(v + offset);
+}
+
+#endif
+
+// Flat array compression that does not emit the "uncompressed length"
+// prefix. Compresses "input" string to the "*op" buffer.
+//
+// REQUIRES: "input" is at most "kBlockSize" bytes long.
+// REQUIRES: "op" points to an array of memory that is at least
+// "MaxCompressedLength(input.size())" in size.
+// REQUIRES: All elements in "table[0..table_size-1]" are initialized to zero.
+// REQUIRES: "table_size" is a power of two
+//
+// Returns an "end" pointer into "op" buffer.
+// "end - op" is the compressed size of "input".
+namespace internal {
+char* CompressFragment(const char* input,
+                       size_t input_size,
+                       char* op,
+                       uint16* table,
+                       const int table_size) {
+  // "ip" is the input pointer, and "op" is the output pointer.
+  const char* ip = input;
+  assert(input_size <= kBlockSize);
+  assert((table_size & (table_size - 1)) == 0); // table must be power of two
+  const int shift = 32 - Bits::Log2Floor(table_size);
+  assert(static_cast<int>(kuint32max >> shift) == table_size - 1);
+  const char* ip_end = input + input_size;
+  const char* base_ip = ip;
+  // Bytes in [next_emit, ip) will be emitted as literal bytes.  Or
+  // [next_emit, ip_end) after the main loop.
+  const char* next_emit = ip;
+
+  const size_t kInputMarginBytes = 15;
+  if (PREDICT_TRUE(input_size >= kInputMarginBytes)) {
+    const char* ip_limit = input + input_size - kInputMarginBytes;
+
+    for (uint32 next_hash = Hash(++ip, shift); ; ) {
+      assert(next_emit < ip);
+      // The body of this loop calls EmitLiteral once and then EmitCopy one or
+      // more times.  (The exception is that when we're close to exhausting
+      // the input we goto emit_remainder.)
+      //
+      // In the first iteration of this loop we're just starting, so
+      // there's nothing to copy, so calling EmitLiteral once is
+      // necessary.  And we only start a new iteration when the
+      // current iteration has determined that a call to EmitLiteral will
+      // precede the next call to EmitCopy (if any).
+      //
+      // Step 1: Scan forward in the input looking for a 4-byte-long match.
+      // If we get close to exhausting the input then goto emit_remainder.
+      //
+      // Heuristic match skipping: If 32 bytes are scanned with no matches
+      // found, start looking only at every other byte. If 32 more bytes are
+      // scanned, look at every third byte, etc.. When a match is found,
+      // immediately go back to looking at every byte. This is a small loss
+      // (~5% performance, ~0.1% density) for compressible data due to more
+      // bookkeeping, but for non-compressible data (such as JPEG) it's a huge
+      // win since the compressor quickly "realizes" the data is incompressible
+      // and doesn't bother looking for matches everywhere.
+      //
+      // The "skip" variable keeps track of how many bytes there are since the
+      // last match; dividing it by 32 (ie. right-shifting by five) gives the
+      // number of bytes to move ahead for each iteration.
+      uint32 skip = 32;
+
+      const char* next_ip = ip;
+      const char* candidate;
+      do {
+        ip = next_ip;
+        uint32 hash = next_hash;
+        assert(hash == Hash(ip, shift));
+        uint32 bytes_between_hash_lookups = skip++ >> 5;
+        next_ip = ip + bytes_between_hash_lookups;
+        if (PREDICT_FALSE(next_ip > ip_limit)) {
+          goto emit_remainder;
+        }
+        next_hash = Hash(next_ip, shift);
+        candidate = base_ip + table[hash];
+        assert(candidate >= base_ip);
+        assert(candidate < ip);
+
+        table[hash] = ip - base_ip;
+      } while (PREDICT_TRUE(UNALIGNED_LOAD32(ip) !=
+                            UNALIGNED_LOAD32(candidate)));
+
+      // Step 2: A 4-byte match has been found.  We'll later see if more
+      // than 4 bytes match.  But, prior to the match, input
+      // bytes [next_emit, ip) are unmatched.  Emit them as "literal bytes."
+      assert(next_emit + 16 <= ip_end);
+      op = EmitLiteral(op, next_emit, ip - next_emit, true);
+
+      // Step 3: Call EmitCopy, and then see if another EmitCopy could
+      // be our next move.  Repeat until we find no match for the
+      // input immediately after what was consumed by the last EmitCopy call.
+      //
+      // If we exit this loop normally then we need to call EmitLiteral next,
+      // though we don't yet know how big the literal will be.  We handle that
+      // by proceeding to the next iteration of the main loop.  We also can exit
+      // this loop via goto if we get close to exhausting the input.
+      EightBytesReference input_bytes;
+      uint32 candidate_bytes = 0;
+
+      do {
+        // We have a 4-byte match at ip, and no need to emit any
+        // "literal bytes" prior to ip.
+        const char* base = ip;
+        int matched = 4 + FindMatchLength(candidate + 4, ip + 4, ip_end);
+        ip += matched;
+        size_t offset = base - candidate;
+        assert(0 == memcmp(base, candidate, matched));
+        op = EmitCopy(op, offset, matched);
+        // We could immediately start working at ip now, but to improve
+        // compression we first update table[Hash(ip - 1, ...)].
+        const char* insert_tail = ip - 1;
+        next_emit = ip;
+        if (PREDICT_FALSE(ip >= ip_limit)) {
+          goto emit_remainder;
+        }
+        input_bytes = GetEightBytesAt(insert_tail);
+        uint32 prev_hash = HashBytes(GetUint32AtOffset(input_bytes, 0), shift);
+        table[prev_hash] = ip - base_ip - 1;
+        uint32 cur_hash = HashBytes(GetUint32AtOffset(input_bytes, 1), shift);
+        candidate = base_ip + table[cur_hash];
+        candidate_bytes = UNALIGNED_LOAD32(candidate);
+        table[cur_hash] = ip - base_ip;
+      } while (GetUint32AtOffset(input_bytes, 1) == candidate_bytes);
+
+      next_hash = HashBytes(GetUint32AtOffset(input_bytes, 2), shift);
+      ++ip;
+    }
+  }
+
+ emit_remainder:
+  // Emit the remaining bytes as a literal
+  if (next_emit < ip_end) {
+    op = EmitLiteral(op, next_emit, ip_end - next_emit, false);
+  }
+
+  return op;
+}
+}  // end namespace internal
+
+// Signature of output types needed by decompression code.
+// The decompression code is templatized on a type that obeys this
+// signature so that we do not pay virtual function call overhead in
+// the middle of a tight decompression loop.
+//
+// class DecompressionWriter {
+//  public:
+//   // Called before decompression
+//   void SetExpectedLength(size_t length);
+//
+//   // Called after decompression
+//   bool CheckLength() const;
+//
+//   // Called repeatedly during decompression
+//   bool Append(const char* ip, size_t length);
+//   bool AppendFromSelf(uint32 offset, size_t length);
+//
+//   // The difference between TryFastAppend and Append is that TryFastAppend
+//   // is allowed to read up to <available> bytes from the input buffer,
+//   // whereas Append is allowed to read <length>.
+//   //
+//   // Also, TryFastAppend is allowed to return false, declining the append,
+//   // without it being a fatal error -- just "return false" would be
+//   // a perfectly legal implementation of TryFastAppend. The intention
+//   // is for TryFastAppend to allow a fast path in the common case of
+//   // a small append.
+//   //
+//   // NOTE(user): TryFastAppend must always return decline (return false)
+//   // if <length> is 61 or more, as in this case the literal length is not
+//   // decoded fully. In practice, this should not be a big problem,
+//   // as it is unlikely that one would implement a fast path accepting
+//   // this much data.
+//   bool TryFastAppend(const char* ip, size_t available, size_t length);
+// };
+
+// -----------------------------------------------------------------------
+// Lookup table for decompression code.  Generated by ComputeTable() below.
+// -----------------------------------------------------------------------
+
+// Mapping from i in range [0,4] to a mask to extract the bottom 8*i bits
+static const uint32 wordmask[] = {
+  0u, 0xffu, 0xffffu, 0xffffffu, 0xffffffffu
+};
+
+// Data stored per entry in lookup table:
+//      Range   Bits-used       Description
+//      ------------------------------------
+//      1..64   0..7            Literal/copy length encoded in opcode byte
+//      0..7    8..10           Copy offset encoded in opcode byte / 256
+//      0..4    11..13          Extra bytes after opcode
+//
+// We use eight bits for the length even though 7 would have sufficed
+// because of efficiency reasons:
+//      (1) Extracting a byte is faster than a bit-field
+//      (2) It properly aligns copy offset so we do not need a <<8
+static const uint16 char_table[256] = {
+  0x0001, 0x0804, 0x1001, 0x2001, 0x0002, 0x0805, 0x1002, 0x2002,
+  0x0003, 0x0806, 0x1003, 0x2003, 0x0004, 0x0807, 0x1004, 0x2004,
+  0x0005, 0x0808, 0x1005, 0x2005, 0x0006, 0x0809, 0x1006, 0x2006,
+  0x0007, 0x080a, 0x1007, 0x2007, 0x0008, 0x080b, 0x1008, 0x2008,
+  0x0009, 0x0904, 0x1009, 0x2009, 0x000a, 0x0905, 0x100a, 0x200a,
+  0x000b, 0x0906, 0x100b, 0x200b, 0x000c, 0x0907, 0x100c, 0x200c,
+  0x000d, 0x0908, 0x100d, 0x200d, 0x000e, 0x0909, 0x100e, 0x200e,
+  0x000f, 0x090a, 0x100f, 0x200f, 0x0010, 0x090b, 0x1010, 0x2010,
+  0x0011, 0x0a04, 0x1011, 0x2011, 0x0012, 0x0a05, 0x1012, 0x2012,
+  0x0013, 0x0a06, 0x1013, 0x2013, 0x0014, 0x0a07, 0x1014, 0x2014,
+  0x0015, 0x0a08, 0x1015, 0x2015, 0x0016, 0x0a09, 0x1016, 0x2016,
+  0x0017, 0x0a0a, 0x1017, 0x2017, 0x0018, 0x0a0b, 0x1018, 0x2018,
+  0x0019, 0x0b04, 0x1019, 0x2019, 0x001a, 0x0b05, 0x101a, 0x201a,
+  0x001b, 0x0b06, 0x101b, 0x201b, 0x001c, 0x0b07, 0x101c, 0x201c,
+  0x001d, 0x0b08, 0x101d, 0x201d, 0x001e, 0x0b09, 0x101e, 0x201e,
+  0x001f, 0x0b0a, 0x101f, 0x201f, 0x0020, 0x0b0b, 0x1020, 0x2020,
+  0x0021, 0x0c04, 0x1021, 0x2021, 0x0022, 0x0c05, 0x1022, 0x2022,
+  0x0023, 0x0c06, 0x1023, 0x2023, 0x0024, 0x0c07, 0x1024, 0x2024,
+  0x0025, 0x0c08, 0x1025, 0x2025, 0x0026, 0x0c09, 0x1026, 0x2026,
+  0x0027, 0x0c0a, 0x1027, 0x2027, 0x0028, 0x0c0b, 0x1028, 0x2028,
+  0x0029, 0x0d04, 0x1029, 0x2029, 0x002a, 0x0d05, 0x102a, 0x202a,
+  0x002b, 0x0d06, 0x102b, 0x202b, 0x002c, 0x0d07, 0x102c, 0x202c,
+  0x002d, 0x0d08, 0x102d, 0x202d, 0x002e, 0x0d09, 0x102e, 0x202e,
+  0x002f, 0x0d0a, 0x102f, 0x202f, 0x0030, 0x0d0b, 0x1030, 0x2030,
+  0x0031, 0x0e04, 0x1031, 0x2031, 0x0032, 0x0e05, 0x1032, 0x2032,
+  0x0033, 0x0e06, 0x1033, 0x2033, 0x0034, 0x0e07, 0x1034, 0x2034,
+  0x0035, 0x0e08, 0x1035, 0x2035, 0x0036, 0x0e09, 0x1036, 0x2036,
+  0x0037, 0x0e0a, 0x1037, 0x2037, 0x0038, 0x0e0b, 0x1038, 0x2038,
+  0x0039, 0x0f04, 0x1039, 0x2039, 0x003a, 0x0f05, 0x103a, 0x203a,
+  0x003b, 0x0f06, 0x103b, 0x203b, 0x003c, 0x0f07, 0x103c, 0x203c,
+  0x0801, 0x0f08, 0x103d, 0x203d, 0x1001, 0x0f09, 0x103e, 0x203e,
+  0x1801, 0x0f0a, 0x103f, 0x203f, 0x2001, 0x0f0b, 0x1040, 0x2040
+};
+
+// In debug mode, allow optional computation of the table at startup.
+// Also, check that the decompression table is correct.
+#ifndef NDEBUG
+DEFINE_bool(snappy_dump_decompression_table, false,
+            "If true, we print the decompression table at startup.");
+
+static uint16 MakeEntry(unsigned int extra,
+                        unsigned int len,
+                        unsigned int copy_offset) {
+  // Check that all of the fields fit within the allocated space
+  assert(extra       == (extra & 0x7));          // At most 3 bits
+  assert(copy_offset == (copy_offset & 0x7));    // At most 3 bits
+  assert(len         == (len & 0x7f));           // At most 7 bits
+  return len | (copy_offset << 8) | (extra << 11);
+}
+
+static void ComputeTable() {
+  uint16 dst[256];
+
+  // Place invalid entries in all places to detect missing initialization
+  int assigned = 0;
+  for (int i = 0; i < 256; i++) {
+    dst[i] = 0xffff;
+  }
+
+  // Small LITERAL entries.  We store (len-1) in the top 6 bits.
+  for (unsigned int len = 1; len <= 60; len++) {
+    dst[LITERAL | ((len-1) << 2)] = MakeEntry(0, len, 0);
+    assigned++;
+  }
+
+  // Large LITERAL entries.  We use 60..63 in the high 6 bits to
+  // encode the number of bytes of length info that follow the opcode.
+  for (unsigned int extra_bytes = 1; extra_bytes <= 4; extra_bytes++) {
+    // We set the length field in the lookup table to 1 because extra
+    // bytes encode len-1.
+    dst[LITERAL | ((extra_bytes+59) << 2)] = MakeEntry(extra_bytes, 1, 0);
+    assigned++;
+  }
+
+  // COPY_1_BYTE_OFFSET.
+  //
+  // The tag byte in the compressed data stores len-4 in 3 bits, and
+  // offset/256 in 5 bits.  offset%256 is stored in the next byte.
+  //
+  // This format is used for length in range [4..11] and offset in
+  // range [0..2047]
+  for (unsigned int len = 4; len < 12; len++) {
+    for (unsigned int offset = 0; offset < 2048; offset += 256) {
+      dst[COPY_1_BYTE_OFFSET | ((len-4)<<2) | ((offset>>8)<<5)] =
+        MakeEntry(1, len, offset>>8);
+      assigned++;
+    }
+  }
+
+  // COPY_2_BYTE_OFFSET.
+  // Tag contains len-1 in top 6 bits, and offset in next two bytes.
+  for (unsigned int len = 1; len <= 64; len++) {
+    dst[COPY_2_BYTE_OFFSET | ((len-1)<<2)] = MakeEntry(2, len, 0);
+    assigned++;
+  }
+
+  // COPY_4_BYTE_OFFSET.
+  // Tag contents len-1 in top 6 bits, and offset in next four bytes.
+  for (unsigned int len = 1; len <= 64; len++) {
+    dst[COPY_4_BYTE_OFFSET | ((len-1)<<2)] = MakeEntry(4, len, 0);
+    assigned++;
+  }
+
+  // Check that each entry was initialized exactly once.
+  if (assigned != 256) {
+    fprintf(stderr, "ComputeTable: assigned only %d of 256\n", assigned);
+    abort();
+  }
+  for (int i = 0; i < 256; i++) {
+    if (dst[i] == 0xffff) {
+      fprintf(stderr, "ComputeTable: did not assign byte %d\n", i);
+      abort();
+    }
+  }
+
+  if (FLAGS_snappy_dump_decompression_table) {
+    printf("static const uint16 char_table[256] = {\n  ");
+    for (int i = 0; i < 256; i++) {
+      printf("0x%04x%s",
+             dst[i],
+             ((i == 255) ? "\n" : (((i%8) == 7) ? ",\n  " : ", ")));
+    }
+    printf("};\n");
+  }
+
+  // Check that computed table matched recorded table
+  for (int i = 0; i < 256; i++) {
+    if (dst[i] != char_table[i]) {
+      fprintf(stderr, "ComputeTable: byte %d: computed (%x), expect (%x)\n",
+              i, static_cast<int>(dst[i]), static_cast<int>(char_table[i]));
+      abort();
+    }
+  }
+}
+#endif /* !NDEBUG */
+
+// Helper class for decompression
+class SnappyDecompressor {
+ private:
+  Source*       reader_;         // Underlying source of bytes to decompress
+  const char*   ip_;             // Points to next buffered byte
+  const char*   ip_limit_;       // Points just past buffered bytes
+  uint32        peeked_;         // Bytes peeked from reader (need to skip)
+  bool          eof_;            // Hit end of input without an error?
+  char          scratch_[5];     // Temporary buffer for PeekFast() boundaries
+
+  // Ensure that all of the tag metadata for the next tag is available
+  // in [ip_..ip_limit_-1].  Also ensures that [ip,ip+4] is readable even
+  // if (ip_limit_ - ip_ < 5).
+  //
+  // Returns true on success, false on error or end of input.
+  bool RefillTag();
+
+ public:
+  explicit SnappyDecompressor(Source* reader)
+      : reader_(reader),
+        ip_(NULL),
+        ip_limit_(NULL),
+        peeked_(0),
+        eof_(false) {
+  }
+
+  ~SnappyDecompressor() {
+    // Advance past any bytes we peeked at from the reader
+    reader_->Skip(peeked_);
+  }
+
+  // Returns true iff we have hit the end of the input without an error.
+  bool eof() const {
+    return eof_;
+  }
+
+  // Read the uncompressed length stored at the start of the compressed data.
+  // On succcess, stores the length in *result and returns true.
+  // On failure, returns false.
+  bool ReadUncompressedLength(uint32* result) {
+    assert(ip_ == NULL);       // Must not have read anything yet
+    // Length is encoded in 1..5 bytes
+    *result = 0;
+    uint32 shift = 0;
+    while (true) {
+      if (shift >= 32) return false;
+      size_t n;
+      const char* ip = reader_->Peek(&n);
+      if (n == 0) return false;
+      const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip));
+      reader_->Skip(1);
+      *result |= static_cast<uint32>(c & 0x7f) << shift;
+      if (c < 128) {
+        break;
+      }
+      shift += 7;
+    }
+    return true;
+  }
+
+  // Process the next item found in the input.
+  // Returns true if successful, false on error or end of input.
+  template <class Writer>
+  void DecompressAllTags(Writer* writer) {
+    const char* ip = ip_;
+
+    // We could have put this refill fragment only at the beginning of the loop.
+    // However, duplicating it at the end of each branch gives the compiler more
+    // scope to optimize the <ip_limit_ - ip> expression based on the local
+    // context, which overall increases speed.
+    #define MAYBE_REFILL() \
+        if (ip_limit_ - ip < 5) { \
+          ip_ = ip; \
+          if (!RefillTag()) return; \
+          ip = ip_; \
+        }
+
+    MAYBE_REFILL();
+    for ( ;; ) {
+      const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip++));
+
+      if ((c & 0x3) == LITERAL) {
+        size_t literal_length = (c >> 2) + 1u;
+        if (writer->TryFastAppend(ip, ip_limit_ - ip, literal_length)) {
+          assert(literal_length < 61);
+          ip += literal_length;
+          MAYBE_REFILL();
+          continue;
+        }
+        if (PREDICT_FALSE(literal_length >= 61)) {
+          // Long literal.
+          const size_t literal_length_length = literal_length - 60;
+          literal_length =
+              (LittleEndian::Load32(ip) & wordmask[literal_length_length]) + 1;
+          ip += literal_length_length;
+        }
+
+        size_t avail = ip_limit_ - ip;
+        while (avail < literal_length) {
+          if (!writer->Append(ip, avail)) return;
+          literal_length -= avail;
+          reader_->Skip(peeked_);
+          size_t n;
+          ip = reader_->Peek(&n);
+          avail = n;
+          peeked_ = avail;
+          if (avail == 0) return;  // Premature end of input
+          ip_limit_ = ip + avail;
+        }
+        if (!writer->Append(ip, literal_length)) {
+          return;
+        }
+        ip += literal_length;
+        MAYBE_REFILL();
+      } else {
+        const uint32 entry = char_table[c];
+        const uint32 trailer = LittleEndian::Load32(ip) & wordmask[entry >> 11];
+        const uint32 length = entry & 0xff;
+        ip += entry >> 11;
+
+        // copy_offset/256 is encoded in bits 8..10.  By just fetching
+        // those bits, we get copy_offset (since the bit-field starts at
+        // bit 8).
+        const uint32 copy_offset = entry & 0x700;
+        if (!writer->AppendFromSelf(copy_offset + trailer, length)) {
+          return;
+        }
+        MAYBE_REFILL();
+      }
+    }
+
+#undef MAYBE_REFILL
+  }
+};
+
+bool SnappyDecompressor::RefillTag() {
+  const char* ip = ip_;
+  if (ip == ip_limit_) {
+    // Fetch a new fragment from the reader
+    reader_->Skip(peeked_);   // All peeked bytes are used up
+    size_t n;
+    ip = reader_->Peek(&n);
+    peeked_ = n;
+    if (n == 0) {
+      eof_ = true;
+      return false;
+    }
+    ip_limit_ = ip + n;
+  }
+
+  // Read the tag character
+  assert(ip < ip_limit_);
+  const unsigned char c = *(reinterpret_cast<const unsigned char*>(ip));
+  const uint32 entry = char_table[c];
+  const uint32 needed = (entry >> 11) + 1;  // +1 byte for 'c'
+  assert(needed <= sizeof(scratch_));
+
+  // Read more bytes from reader if needed
+  uint32 nbuf = ip_limit_ - ip;
+  if (nbuf < needed) {
+    // Stitch together bytes from ip and reader to form the word
+    // contents.  We store the needed bytes in "scratch_".  They
+    // will be consumed immediately by the caller since we do not
+    // read more than we need.
+    memmove(scratch_, ip, nbuf);
+    reader_->Skip(peeked_);  // All peeked bytes are used up
+    peeked_ = 0;
+    while (nbuf < needed) {
+      size_t length;
+      const char* src = reader_->Peek(&length);
+      if (length == 0) return false;
+      uint32 to_add = min<uint32>(needed - nbuf, length);
+      memcpy(scratch_ + nbuf, src, to_add);
+      nbuf += to_add;
+      reader_->Skip(to_add);
+    }
+    assert(nbuf == needed);
+    ip_ = scratch_;
+    ip_limit_ = scratch_ + needed;
+  } else if (nbuf < 5) {
+    // Have enough bytes, but move into scratch_ so that we do not
+    // read past end of input
+    memmove(scratch_, ip, nbuf);
+    reader_->Skip(peeked_);  // All peeked bytes are used up
+    peeked_ = 0;
+    ip_ = scratch_;
+    ip_limit_ = scratch_ + nbuf;
+  } else {
+    // Pass pointer to buffer returned by reader_.
+    ip_ = ip;
+  }
+  return true;
+}
+
+template <typename Writer>
+static bool InternalUncompress(Source* r,
+                               Writer* writer,
+                               uint32 max_len) {
+  // Read the uncompressed length from the front of the compressed input
+  SnappyDecompressor decompressor(r);
+  uint32 uncompressed_len = 0;
+  if (!decompressor.ReadUncompressedLength(&uncompressed_len)) return false;
+  return InternalUncompressAllTags(
+      &decompressor, writer, uncompressed_len, max_len);
+}
+
+template <typename Writer>
+static bool InternalUncompressAllTags(SnappyDecompressor* decompressor,
+                                      Writer* writer,
+                                      uint32 uncompressed_len,
+                                      uint32 max_len) {
+  // Protect against possible DoS attack
+  if (static_cast<uint64>(uncompressed_len) > max_len) {
+    return false;
+  }
+
+  writer->SetExpectedLength(uncompressed_len);
+
+  // Process the entire input
+  decompressor->DecompressAllTags(writer);
+  return (decompressor->eof() && writer->CheckLength());
+}
+
+bool GetUncompressedLength(Source* source, uint32* result) {
+  SnappyDecompressor decompressor(source);
+  return decompressor.ReadUncompressedLength(result);
+}
+
+size_t Compress(Source* reader, Sink* writer) {
+  size_t written = 0;
+  size_t N = reader->Available();
+  char ulength[Varint::kMax32];
+  char* p = Varint::Encode32(ulength, N);
+  writer->Append(ulength, p-ulength);
+  written += (p - ulength);
+
+  internal::WorkingMemory wmem;
+  char* scratch = NULL;
+  char* scratch_output = NULL;
+
+  while (N > 0) {
+    // Get next block to compress (without copying if possible)
+    size_t fragment_size;
+    const char* fragment = reader->Peek(&fragment_size);
+    assert(fragment_size != 0);  // premature end of input
+    const size_t num_to_read = min(N, kBlockSize);
+    size_t bytes_read = fragment_size;
+
+    size_t pending_advance = 0;
+    if (bytes_read >= num_to_read) {
+      // Buffer returned by reader is large enough
+      pending_advance = num_to_read;
+      fragment_size = num_to_read;
+    } else {
+      // Read into scratch buffer
+      if (scratch == NULL) {
+        // If this is the last iteration, we want to allocate N bytes
+        // of space, otherwise the max possible kBlockSize space.
+        // num_to_read contains exactly the correct value
+        scratch = new char[num_to_read];
+      }
+      memcpy(scratch, fragment, bytes_read);
+      reader->Skip(bytes_read);
+
+      while (bytes_read < num_to_read) {
+        fragment = reader->Peek(&fragment_size);
+        size_t n = min<size_t>(fragment_size, num_to_read - bytes_read);
+        memcpy(scratch + bytes_read, fragment, n);
+        bytes_read += n;
+        reader->Skip(n);
+      }
+      assert(bytes_read == num_to_read);
+      fragment = scratch;
+      fragment_size = num_to_read;
+    }
+    assert(fragment_size == num_to_read);
+
+    // Get encoding table for compression
+    int table_size;
+    uint16* table = wmem.GetHashTable(num_to_read, &table_size);
+
+    // Compress input_fragment and append to dest
+    const int max_output = MaxCompressedLength(num_to_read);
+
+    // Need a scratch buffer for the output, in case the byte sink doesn't
+    // have room for us directly.
+    if (scratch_output == NULL) {
+      scratch_output = new char[max_output];
+    } else {
+      // Since we encode kBlockSize regions followed by a region
+      // which is <= kBlockSize in length, a previously allocated
+      // scratch_output[] region is big enough for this iteration.
+    }
+    char* dest = writer->GetAppendBuffer(max_output, scratch_output);
+    char* end = internal::CompressFragment(fragment, fragment_size,
+                                           dest, table, table_size);
+    writer->Append(dest, end - dest);
+    written += (end - dest);
+
+    N -= num_to_read;
+    reader->Skip(pending_advance);
+  }
+
+  delete[] scratch;
+  delete[] scratch_output;
+
+  return written;
+}
+
+// -----------------------------------------------------------------------
+// Flat array interfaces
+// -----------------------------------------------------------------------
+
+// A type that writes to a flat array.
+// Note that this is not a "ByteSink", but a type that matches the
+// Writer template argument to SnappyDecompressor::DecompressAllTags().
+class SnappyArrayWriter {
+ private:
+  char* base_;
+  char* op_;
+  char* op_limit_;
+
+ public:
+  inline explicit SnappyArrayWriter(char* dst)
+      : base_(dst),
+        op_(dst) {
+  }
+
+  inline void SetExpectedLength(size_t len) {
+    op_limit_ = op_ + len;
+  }
+
+  inline bool CheckLength() const {
+    return op_ == op_limit_;
+  }
+
+  inline bool Append(const char* ip, size_t len) {
+    char* op = op_;
+    const size_t space_left = op_limit_ - op;
+    if (space_left < len) {
+      return false;
+    }
+    memcpy(op, ip, len);
+    op_ = op + len;
+    return true;
+  }
+
+  inline bool TryFastAppend(const char* ip, size_t available, size_t len) {
+    char* op = op_;
+    const size_t space_left = op_limit_ - op;
+    if (len <= 16 && available >= 16 && space_left >= 16) {
+      // Fast path, used for the majority (about 95%) of invocations.
+      UnalignedCopy64(ip, op);
+      UnalignedCopy64(ip + 8, op + 8);
+      op_ = op + len;
+      return true;
+    } else {
+      return false;
+    }
+  }
+
+  inline bool AppendFromSelf(size_t offset, size_t len) {
+    char* op = op_;
+    const size_t space_left = op_limit_ - op;
+
+    if (op - base_ <= offset - 1u) {  // -1u catches offset==0
+      return false;
+    }
+    if (len <= 16 && offset >= 8 && space_left >= 16) {
+      // Fast path, used for the majority (70-80%) of dynamic invocations.
+      UnalignedCopy64(op - offset, op);
+      UnalignedCopy64(op - offset + 8, op + 8);
+    } else {
+      if (space_left >= len + kMaxIncrementCopyOverflow) {
+        IncrementalCopyFastPath(op - offset, op, len);
+      } else {
+        if (space_left < len) {
+          return false;
+        }
+        IncrementalCopy(op - offset, op, len);
+      }
+    }
+
+    op_ = op + len;
+    return true;
+  }
+};
+
+bool RawUncompress(const char* compressed, size_t n, char* uncompressed) {
+  ByteArraySource reader(compressed, n);
+  return RawUncompress(&reader, uncompressed);
+}
+
+bool RawUncompress(Source* compressed, char* uncompressed) {
+  SnappyArrayWriter output(uncompressed);
+  return InternalUncompress(compressed, &output, kuint32max);
+}
+
+bool Uncompress(const char* compressed, size_t n, string* uncompressed) {
+  size_t ulength;
+  if (!GetUncompressedLength(compressed, n, &ulength)) {
+    return false;
+  }
+  // Protect against possible DoS attack
+  if ((static_cast<uint64>(ulength) + uncompressed->size()) >
+      uncompressed->max_size()) {
+    return false;
+  }
+  STLStringResizeUninitialized(uncompressed, ulength);
+  return RawUncompress(compressed, n, string_as_array(uncompressed));
+}
+
+
+// A Writer that drops everything on the floor and just does validation
+class SnappyDecompressionValidator {
+ private:
+  size_t expected_;
+  size_t produced_;
+
+ public:
+  inline SnappyDecompressionValidator() : produced_(0) { }
+  inline void SetExpectedLength(size_t len) {
+    expected_ = len;
+  }
+  inline bool CheckLength() const {
+    return expected_ == produced_;
+  }
+  inline bool Append(const char* ip, size_t len) {
+    produced_ += len;
+    return produced_ <= expected_;
+  }
+  inline bool TryFastAppend(const char* ip, size_t available, size_t length) {
+    return false;
+  }
+  inline bool AppendFromSelf(size_t offset, size_t len) {
+    if (produced_ <= offset - 1u) return false;  // -1u catches offset==0
+    produced_ += len;
+    return produced_ <= expected_;
+  }
+};
+
+bool IsValidCompressedBuffer(const char* compressed, size_t n) {
+  ByteArraySource reader(compressed, n);
+  SnappyDecompressionValidator writer;
+  return InternalUncompress(&reader, &writer, kuint32max);
+}
+
+void RawCompress(const char* input,
+                 size_t input_length,
+                 char* compressed,
+                 size_t* compressed_length) {
+  ByteArraySource reader(input, input_length);
+  UncheckedByteArraySink writer(compressed);
+  Compress(&reader, &writer);
+
+  // Compute how many bytes were added
+  *compressed_length = (writer.CurrentDestination() - compressed);
+}
+
+size_t Compress(const char* input, size_t input_length, string* compressed) {
+  // Pre-grow the buffer to the max length of the compressed output
+  compressed->resize(MaxCompressedLength(input_length));
+
+  size_t compressed_length;
+  RawCompress(input, input_length, string_as_array(compressed),
+              &compressed_length);
+  compressed->resize(compressed_length);
+  return compressed_length;
+}
+
+
+} // end namespace snappy
+
diff --git a/snappy/snappy.h b/snappy/snappy.h
new file mode 100644
index 00000000..03ef6ce5
--- /dev/null
+++ b/snappy/snappy.h
@@ -0,0 +1,163 @@
+// Copyright 2005 and onwards Google Inc.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+//
+// A light-weight compression algorithm.  It is designed for speed of
+// compression and decompression, rather than for the utmost in space
+// savings.
+//
+// For getting better compression ratios when you are compressing data
+// with long repeated sequences or compressing data that is similar to
+// other data, while still compressing fast, you might look at first
+// using BMDiff and then compressing the output of BMDiff with
+// Snappy.
+
+#ifndef UTIL_SNAPPY_SNAPPY_H__
+#define UTIL_SNAPPY_SNAPPY_H__
+
+#include <stddef.h>
+#include <string>
+
+#include "snappy-stubs-public.h"
+
+namespace snappy {
+  class Source;
+  class Sink;
+
+  // ------------------------------------------------------------------------
+  // Generic compression/decompression routines.
+  // ------------------------------------------------------------------------
+
+  // Compress the bytes read from "*source" and append to "*sink". Return the
+  // number of bytes written.
+  size_t Compress(Source* source, Sink* sink);
+
+  // Find the uncompressed length of the given stream, as given by the header.
+  // Note that the true length could deviate from this; the stream could e.g.
+  // be truncated.
+  //
+  // Also note that this leaves "*source" in a state that is unsuitable for
+  // further operations, such as RawUncompress(). You will need to rewind
+  // or recreate the source yourself before attempting any further calls.
+  bool GetUncompressedLength(Source* source, uint32* result);
+
+  // ------------------------------------------------------------------------
+  // Higher-level string based routines (should be sufficient for most users)
+  // ------------------------------------------------------------------------
+
+  // Sets "*output" to the compressed version of "input[0,input_length-1]".
+  // Original contents of *output are lost.
+  //
+  // REQUIRES: "input[]" is not an alias of "*output".
+  size_t Compress(const char* input, size_t input_length, string* output);
+
+  // Decompresses "compressed[0,compressed_length-1]" to "*uncompressed".
+  // Original contents of "*uncompressed" are lost.
+  //
+  // REQUIRES: "compressed[]" is not an alias of "*uncompressed".
+  //
+  // returns false if the message is corrupted and could not be decompressed
+  bool Uncompress(const char* compressed, size_t compressed_length,
+                  string* uncompressed);
+
+
+  // ------------------------------------------------------------------------
+  // Lower-level character array based routines.  May be useful for
+  // efficiency reasons in certain circumstances.
+  // ------------------------------------------------------------------------
+
+  // REQUIRES: "compressed" must point to an area of memory that is at
+  // least "MaxCompressedLength(input_length)" bytes in length.
+  //
+  // Takes the data stored in "input[0..input_length]" and stores
+  // it in the array pointed to by "compressed".
+  //
+  // "*compressed_length" is set to the length of the compressed output.
+  //
+  // Example:
+  //    char* output = new char[snappy::MaxCompressedLength(input_length)];
+  //    size_t output_length;
+  //    RawCompress(input, input_length, output, &output_length);
+  //    ... Process(output, output_length) ...
+  //    delete [] output;
+  void RawCompress(const char* input,
+                   size_t input_length,
+                   char* compressed,
+                   size_t* compressed_length);
+
+  // Given data in "compressed[0..compressed_length-1]" generated by
+  // calling the Snappy::Compress routine, this routine
+  // stores the uncompressed data to
+  //    uncompressed[0..GetUncompressedLength(compressed)-1]
+  // returns false if the message is corrupted and could not be decrypted
+  bool RawUncompress(const char* compressed, size_t compressed_length,
+                     char* uncompressed);
+
+  // Given data from the byte source 'compressed' generated by calling
+  // the Snappy::Compress routine, this routine stores the uncompressed
+  // data to
+  //    uncompressed[0..GetUncompressedLength(compressed,compressed_length)-1]
+  // returns false if the message is corrupted and could not be decrypted
+  bool RawUncompress(Source* compressed, char* uncompressed);
+
+  // Returns the maximal size of the compressed representation of
+  // input data that is "source_bytes" bytes in length;
+  size_t MaxCompressedLength(size_t source_bytes);
+
+  // REQUIRES: "compressed[]" was produced by RawCompress() or Compress()
+  // Returns true and stores the length of the uncompressed data in
+  // *result normally.  Returns false on parsing error.
+  // This operation takes O(1) time.
+  bool GetUncompressedLength(const char* compressed, size_t compressed_length,
+                             size_t* result);
+
+  // Returns true iff the contents of "compressed[]" can be uncompressed
+  // successfully.  Does not return the uncompressed data.  Takes
+  // time proportional to compressed_length, but is usually at least
+  // a factor of four faster than actual decompression.
+  bool IsValidCompressedBuffer(const char* compressed,
+                               size_t compressed_length);
+
+  // The size of a compression block. Note that many parts of the compression
+  // code assumes that kBlockSize <= 65536; in particular, the hash table
+  // can only store 16-bit offsets, and EmitCopy() also assumes the offset
+  // is 65535 bytes or less. Note also that if you change this, it will
+  // affect the framing format (see framing_format.txt).
+  //
+  // Note that there might be older data around that is compressed with larger
+  // block sizes, so the decompression code should not rely on the
+  // non-existence of long backreferences.
+  static const int kBlockLog = 16;
+  static const size_t kBlockSize = 1 << kBlockLog;
+
+  static const int kMaxHashTableBits = 14;
+  static const size_t kMaxHashTableSize = 1 << kMaxHashTableBits;
+
+}  // end namespace snappy
+
+
+#endif  // UTIL_SNAPPY_SNAPPY_H__
diff --git a/snappy/snappy_unittest.cc b/snappy/snappy_unittest.cc
new file mode 100644
index 00000000..59c108f4
--- /dev/null
+++ b/snappy/snappy_unittest.cc
@@ -0,0 +1,1164 @@
+// Copyright 2005 and onwards Google Inc.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include <math.h>
+#include <stdlib.h>
+
+
+#include <algorithm>
+#include <string>
+#include <vector>
+
+#include "snappy.h"
+#include "snappy-internal.h"
+#include "snappy-test.h"
+#include "snappy-sinksource.h"
+
+DEFINE_int32(start_len, -1,
+             "Starting prefix size for testing (-1: just full file contents)");
+DEFINE_int32(end_len, -1,
+             "Starting prefix size for testing (-1: just full file contents)");
+DEFINE_int32(bytes, 10485760,
+             "How many bytes to compress/uncompress per file for timing");
+
+DEFINE_bool(zlib, false,
+            "Run zlib compression (http://www.zlib.net)");
+DEFINE_bool(lzo, false,
+            "Run LZO compression (http://www.oberhumer.com/opensource/lzo/)");
+DEFINE_bool(quicklz, false,
+            "Run quickLZ compression (http://www.quicklz.com/)");
+DEFINE_bool(liblzf, false,
+            "Run libLZF compression "
+            "(http://www.goof.com/pcg/marc/liblzf.html)");
+DEFINE_bool(fastlz, false,
+            "Run FastLZ compression (http://www.fastlz.org/");
+DEFINE_bool(snappy, true, "Run snappy compression");
+
+
+DEFINE_bool(write_compressed, false,
+            "Write compressed versions of each file to <file>.comp");
+DEFINE_bool(write_uncompressed, false,
+            "Write uncompressed versions of each file to <file>.uncomp");
+
+namespace snappy {
+
+
+#ifdef HAVE_FUNC_MMAP
+
+// To test against code that reads beyond its input, this class copies a
+// string to a newly allocated group of pages, the last of which
+// is made unreadable via mprotect. Note that we need to allocate the
+// memory with mmap(), as POSIX allows mprotect() only on memory allocated
+// with mmap(), and some malloc/posix_memalign implementations expect to
+// be able to read previously allocated memory while doing heap allocations.
+class DataEndingAtUnreadablePage {
+ public:
+  explicit DataEndingAtUnreadablePage(const string& s) {
+    const size_t page_size = getpagesize();
+    const size_t size = s.size();
+    // Round up space for string to a multiple of page_size.
+    size_t space_for_string = (size + page_size - 1) & ~(page_size - 1);
+    alloc_size_ = space_for_string + page_size;
+    mem_ = mmap(NULL, alloc_size_,
+                PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+    CHECK_NE(MAP_FAILED, mem_);
+    protected_page_ = reinterpret_cast<char*>(mem_) + space_for_string;
+    char* dst = protected_page_ - size;
+    memcpy(dst, s.data(), size);
+    data_ = dst;
+    size_ = size;
+    // Make guard page unreadable.
+    CHECK_EQ(0, mprotect(protected_page_, page_size, PROT_NONE));
+  }
+
+  ~DataEndingAtUnreadablePage() {
+    // Undo the mprotect.
+    CHECK_EQ(0, mprotect(protected_page_, getpagesize(), PROT_READ|PROT_WRITE));
+    CHECK_EQ(0, munmap(mem_, alloc_size_));
+  }
+
+  const char* data() const { return data_; }
+  size_t size() const { return size_; }
+
+ private:
+  size_t alloc_size_;
+  void* mem_;
+  char* protected_page_;
+  const char* data_;
+  size_t size_;
+};
+
+#else  // HAVE_FUNC_MMAP
+
+// Fallback for systems without mmap.
+typedef string DataEndingAtUnreadablePage;
+
+#endif
+
+enum CompressorType {
+  ZLIB, LZO, LIBLZF, QUICKLZ, FASTLZ, SNAPPY
+};
+
+const char* names[] = {
+  "ZLIB", "LZO", "LIBLZF", "QUICKLZ", "FASTLZ", "SNAPPY"
+};
+
+static size_t MinimumRequiredOutputSpace(size_t input_size,
+                                         CompressorType comp) {
+  switch (comp) {
+#ifdef ZLIB_VERSION
+    case ZLIB:
+      return ZLib::MinCompressbufSize(input_size);
+#endif  // ZLIB_VERSION
+
+#ifdef LZO_VERSION
+    case LZO:
+      return input_size + input_size/64 + 16 + 3;
+#endif  // LZO_VERSION
+
+#ifdef LZF_VERSION
+    case LIBLZF:
+      return input_size;
+#endif  // LZF_VERSION
+
+#ifdef QLZ_VERSION_MAJOR
+    case QUICKLZ:
+      return input_size + 36000;  // 36000 is used for scratch.
+#endif  // QLZ_VERSION_MAJOR
+
+#ifdef FASTLZ_VERSION
+    case FASTLZ:
+      return max(static_cast<int>(ceil(input_size * 1.05)), 66);
+#endif  // FASTLZ_VERSION
+
+    case SNAPPY:
+      return snappy::MaxCompressedLength(input_size);
+
+    default:
+      LOG(FATAL) << "Unknown compression type number " << comp;
+  }
+}
+
+// Returns true if we successfully compressed, false otherwise.
+//
+// If compressed_is_preallocated is set, do not resize the compressed buffer.
+// This is typically what you want for a benchmark, in order to not spend
+// time in the memory allocator. If you do set this flag, however,
+// "compressed" must be preinitialized to at least MinCompressbufSize(comp)
+// number of bytes, and may contain junk bytes at the end after return.
+static bool Compress(const char* input, size_t input_size, CompressorType comp,
+                     string* compressed, bool compressed_is_preallocated) {
+  if (!compressed_is_preallocated) {
+    compressed->resize(MinimumRequiredOutputSpace(input_size, comp));
+  }
+
+  switch (comp) {
+#ifdef ZLIB_VERSION
+    case ZLIB: {
+      ZLib zlib;
+      uLongf destlen = compressed->size();
+      int ret = zlib.Compress(
+          reinterpret_cast<Bytef*>(string_as_array(compressed)),
+          &destlen,
+          reinterpret_cast<const Bytef*>(input),
+          input_size);
+      CHECK_EQ(Z_OK, ret);
+      if (!compressed_is_preallocated) {
+        compressed->resize(destlen);
+      }
+      return true;
+    }
+#endif  // ZLIB_VERSION
+
+#ifdef LZO_VERSION
+    case LZO: {
+      unsigned char* mem = new unsigned char[LZO1X_1_15_MEM_COMPRESS];
+      lzo_uint destlen;
+      int ret = lzo1x_1_15_compress(
+          reinterpret_cast<const uint8*>(input),
+          input_size,
+          reinterpret_cast<uint8*>(string_as_array(compressed)),
+          &destlen,
+          mem);
+      CHECK_EQ(LZO_E_OK, ret);
+      delete[] mem;
+      if (!compressed_is_preallocated) {
+        compressed->resize(destlen);
+      }
+      break;
+    }
+#endif  // LZO_VERSION
+
+#ifdef LZF_VERSION
+    case LIBLZF: {
+      int destlen = lzf_compress(input,
+                                 input_size,
+                                 string_as_array(compressed),
+                                 input_size);
+      if (destlen == 0) {
+        // lzf *can* cause lots of blowup when compressing, so they
+        // recommend to limit outsize to insize, and just not compress
+        // if it's bigger.  Ideally, we'd just swap input and output.
+        compressed->assign(input, input_size);
+        destlen = input_size;
+      }
+      if (!compressed_is_preallocated) {
+        compressed->resize(destlen);
+      }
+      break;
+    }
+#endif  // LZF_VERSION
+
+#ifdef QLZ_VERSION_MAJOR
+    case QUICKLZ: {
+      qlz_state_compress *state_compress = new qlz_state_compress;
+      int destlen = qlz_compress(input,
+                                 string_as_array(compressed),
+                                 input_size,
+                                 state_compress);
+      delete state_compress;
+      CHECK_NE(0, destlen);
+      if (!compressed_is_preallocated) {
+        compressed->resize(destlen);
+      }
+      break;
+    }
+#endif  // QLZ_VERSION_MAJOR
+
+#ifdef FASTLZ_VERSION
+    case FASTLZ: {
+      // Use level 1 compression since we mostly care about speed.
+      int destlen = fastlz_compress_level(
+          1,
+          input,
+          input_size,
+          string_as_array(compressed));
+      if (!compressed_is_preallocated) {
+        compressed->resize(destlen);
+      }
+      CHECK_NE(destlen, 0);
+      break;
+    }
+#endif  // FASTLZ_VERSION
+
+    case SNAPPY: {
+      size_t destlen;
+      snappy::RawCompress(input, input_size,
+                          string_as_array(compressed),
+                          &destlen);
+      CHECK_LE(destlen, snappy::MaxCompressedLength(input_size));
+      if (!compressed_is_preallocated) {
+        compressed->resize(destlen);
+      }
+      break;
+    }
+
+
+    default: {
+      return false;     // the asked-for library wasn't compiled in
+    }
+  }
+  return true;
+}
+
+static bool Uncompress(const string& compressed, CompressorType comp,
+                       int size, string* output) {
+  switch (comp) {
+#ifdef ZLIB_VERSION
+    case ZLIB: {
+      output->resize(size);
+      ZLib zlib;
+      uLongf destlen = output->size();
+      int ret = zlib.Uncompress(
+          reinterpret_cast<Bytef*>(string_as_array(output)),
+          &destlen,
+          reinterpret_cast<const Bytef*>(compressed.data()),
+          compressed.size());
+      CHECK_EQ(Z_OK, ret);
+      CHECK_EQ(static_cast<uLongf>(size), destlen);
+      break;
+    }
+#endif  // ZLIB_VERSION
+
+#ifdef LZO_VERSION
+    case LZO: {
+      output->resize(size);
+      lzo_uint destlen;
+      int ret = lzo1x_decompress(
+          reinterpret_cast<const uint8*>(compressed.data()),
+          compressed.size(),
+          reinterpret_cast<uint8*>(string_as_array(output)),
+          &destlen,
+          NULL);
+      CHECK_EQ(LZO_E_OK, ret);
+      CHECK_EQ(static_cast<lzo_uint>(size), destlen);
+      break;
+    }
+#endif  // LZO_VERSION
+
+#ifdef LZF_VERSION
+    case LIBLZF: {
+      output->resize(size);
+      int destlen = lzf_decompress(compressed.data(),
+                                   compressed.size(),
+                                   string_as_array(output),
+                                   output->size());
+      if (destlen == 0) {
+        // This error probably means we had decided not to compress,
+        // and thus have stored input in output directly.
+        output->assign(compressed.data(), compressed.size());
+        destlen = compressed.size();
+      }
+      CHECK_EQ(destlen, size);
+      break;
+    }
+#endif  // LZF_VERSION
+
+#ifdef QLZ_VERSION_MAJOR
+    case QUICKLZ: {
+      output->resize(size);
+      qlz_state_decompress *state_decompress = new qlz_state_decompress;
+      int destlen = qlz_decompress(compressed.data(),
+                                   string_as_array(output),
+                                   state_decompress);
+      delete state_decompress;
+      CHECK_EQ(destlen, size);
+      break;
+    }
+#endif  // QLZ_VERSION_MAJOR
+
+#ifdef FASTLZ_VERSION
+    case FASTLZ: {
+      output->resize(size);
+      int destlen = fastlz_decompress(compressed.data(),
+                                      compressed.length(),
+                                      string_as_array(output),
+                                      size);
+      CHECK_EQ(destlen, size);
+      break;
+    }
+#endif  // FASTLZ_VERSION
+
+    case SNAPPY: {
+      snappy::RawUncompress(compressed.data(), compressed.size(),
+                            string_as_array(output));
+      break;
+    }
+
+
+    default: {
+      return false;     // the asked-for library wasn't compiled in
+    }
+  }
+  return true;
+}
+
+static void Measure(const char* data,
+                    size_t length,
+                    CompressorType comp,
+                    int repeats,
+                    int block_size) {
+  // Run tests a few time and pick median running times
+  static const int kRuns = 5;
+  double ctime[kRuns];
+  double utime[kRuns];
+  int compressed_size = 0;
+
+  {
+    // Chop the input into blocks
+    int num_blocks = (length + block_size - 1) / block_size;
+    vector<const char*> input(num_blocks);
+    vector<size_t> input_length(num_blocks);
+    vector<string> compressed(num_blocks);
+    vector<string> output(num_blocks);
+    for (int b = 0; b < num_blocks; b++) {
+      int input_start = b * block_size;
+      int input_limit = min<int>((b+1)*block_size, length);
+      input[b] = data+input_start;
+      input_length[b] = input_limit-input_start;
+
+      // Pre-grow the output buffer so we don't measure string append time.
+      compressed[b].resize(MinimumRequiredOutputSpace(block_size, comp));
+    }
+
+    // First, try one trial compression to make sure the code is compiled in
+    if (!Compress(input[0], input_length[0], comp, &compressed[0], true)) {
+      LOG(WARNING) << "Skipping " << names[comp] << ": "
+                   << "library not compiled in";
+      return;
+    }
+
+    for (int run = 0; run < kRuns; run++) {
+      CycleTimer ctimer, utimer;
+
+      for (int b = 0; b < num_blocks; b++) {
+        // Pre-grow the output buffer so we don't measure string append time.
+        compressed[b].resize(MinimumRequiredOutputSpace(block_size, comp));
+      }
+
+      ctimer.Start();
+      for (int b = 0; b < num_blocks; b++)
+        for (int i = 0; i < repeats; i++)
+          Compress(input[b], input_length[b], comp, &compressed[b], true);
+      ctimer.Stop();
+
+      // Compress once more, with resizing, so we don't leave junk
+      // at the end that will confuse the decompressor.
+      for (int b = 0; b < num_blocks; b++) {
+        Compress(input[b], input_length[b], comp, &compressed[b], false);
+      }
+
+      for (int b = 0; b < num_blocks; b++) {
+        output[b].resize(input_length[b]);
+      }
+
+      utimer.Start();
+      for (int i = 0; i < repeats; i++)
+        for (int b = 0; b < num_blocks; b++)
+          Uncompress(compressed[b], comp, input_length[b], &output[b]);
+      utimer.Stop();
+
+      ctime[run] = ctimer.Get();
+      utime[run] = utimer.Get();
+    }
+
+    compressed_size = 0;
+    for (int i = 0; i < compressed.size(); i++) {
+      compressed_size += compressed[i].size();
+    }
+  }
+
+  sort(ctime, ctime + kRuns);
+  sort(utime, utime + kRuns);
+  const int med = kRuns/2;
+
+  float comp_rate = (length / ctime[med]) * repeats / 1048576.0;
+  float uncomp_rate = (length / utime[med]) * repeats / 1048576.0;
+  string x = names[comp];
+  x += ":";
+  string urate = (uncomp_rate >= 0)
+                 ? StringPrintf("%.1f", uncomp_rate)
+                 : string("?");
+  printf("%-7s [b %dM] bytes %6d -> %6d %4.1f%%  "
+         "comp %5.1f MB/s  uncomp %5s MB/s\n",
+         x.c_str(),
+         block_size/(1<<20),
+         static_cast<int>(length), static_cast<uint32>(compressed_size),
+         (compressed_size * 100.0) / max<int>(1, length),
+         comp_rate,
+         urate.c_str());
+}
+
+
+static int VerifyString(const string& input) {
+  string compressed;
+  DataEndingAtUnreadablePage i(input);
+  const size_t written = snappy::Compress(i.data(), i.size(), &compressed);
+  CHECK_EQ(written, compressed.size());
+  CHECK_LE(compressed.size(),
+           snappy::MaxCompressedLength(input.size()));
+  CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+
+  string uncompressed;
+  DataEndingAtUnreadablePage c(compressed);
+  CHECK(snappy::Uncompress(c.data(), c.size(), &uncompressed));
+  CHECK_EQ(uncompressed, input);
+  return uncompressed.size();
+}
+
+
+// Test that data compressed by a compressor that does not
+// obey block sizes is uncompressed properly.
+static void VerifyNonBlockedCompression(const string& input) {
+  if (input.length() > snappy::kBlockSize) {
+    // We cannot test larger blocks than the maximum block size, obviously.
+    return;
+  }
+
+  string prefix;
+  Varint::Append32(&prefix, input.size());
+
+  // Setup compression table
+  snappy::internal::WorkingMemory wmem;
+  int table_size;
+  uint16* table = wmem.GetHashTable(input.size(), &table_size);
+
+  // Compress entire input in one shot
+  string compressed;
+  compressed += prefix;
+  compressed.resize(prefix.size()+snappy::MaxCompressedLength(input.size()));
+  char* dest = string_as_array(&compressed) + prefix.size();
+  char* end = snappy::internal::CompressFragment(input.data(), input.size(),
+                                                dest, table, table_size);
+  compressed.resize(end - compressed.data());
+
+  // Uncompress into string
+  string uncomp_str;
+  CHECK(snappy::Uncompress(compressed.data(), compressed.size(), &uncomp_str));
+  CHECK_EQ(uncomp_str, input);
+
+}
+
+// Expand the input so that it is at least K times as big as block size
+static string Expand(const string& input) {
+  static const int K = 3;
+  string data = input;
+  while (data.size() < K * snappy::kBlockSize) {
+    data += input;
+  }
+  return data;
+}
+
+static int Verify(const string& input) {
+  VLOG(1) << "Verifying input of size " << input.size();
+
+  // Compress using string based routines
+  const int result = VerifyString(input);
+
+
+  VerifyNonBlockedCompression(input);
+  if (!input.empty()) {
+    VerifyNonBlockedCompression(Expand(input));
+  }
+
+
+  return result;
+}
+
+// This test checks to ensure that snappy doesn't coredump if it gets
+// corrupted data.
+
+static bool IsValidCompressedBuffer(const string& c) {
+  return snappy::IsValidCompressedBuffer(c.data(), c.size());
+}
+static bool Uncompress(const string& c, string* u) {
+  return snappy::Uncompress(c.data(), c.size(), u);
+}
+
+TYPED_TEST(CorruptedTest, VerifyCorrupted) {
+  string source = "making sure we don't crash with corrupted input";
+  VLOG(1) << source;
+  string dest;
+  TypeParam uncmp;
+  snappy::Compress(source.data(), source.size(), &dest);
+
+  // Mess around with the data. It's hard to simulate all possible
+  // corruptions; this is just one example ...
+  CHECK_GT(dest.size(), 3);
+  dest[1]--;
+  dest[3]++;
+  // this really ought to fail.
+  CHECK(!IsValidCompressedBuffer(TypeParam(dest)));
+  CHECK(!Uncompress(TypeParam(dest), &uncmp));
+
+  // This is testing for a security bug - a buffer that decompresses to 100k
+  // but we lie in the snappy header and only reserve 0 bytes of memory :)
+  source.resize(100000);
+  for (int i = 0; i < source.length(); ++i) {
+    source[i] = 'A';
+  }
+  snappy::Compress(source.data(), source.size(), &dest);
+  dest[0] = dest[1] = dest[2] = dest[3] = 0;
+  CHECK(!IsValidCompressedBuffer(TypeParam(dest)));
+  CHECK(!Uncompress(TypeParam(dest), &uncmp));
+
+  if (sizeof(void *) == 4) {
+    // Another security check; check a crazy big length can't DoS us with an
+    // over-allocation.
+    // Currently this is done only for 32-bit builds.  On 64-bit builds,
+    // where 3 GB might be an acceptable allocation size, Uncompress()
+    // attempts to decompress, and sometimes causes the test to run out of
+    // memory.
+    dest[0] = dest[1] = dest[2] = dest[3] = 0xff;
+    // This decodes to a really large size, i.e., about 3 GB.
+    dest[4] = 'k';
+    CHECK(!IsValidCompressedBuffer(TypeParam(dest)));
+    CHECK(!Uncompress(TypeParam(dest), &uncmp));
+  } else {
+    LOG(WARNING) << "Crazy decompression lengths not checked on 64-bit build";
+  }
+
+  // This decodes to about 2 MB; much smaller, but should still fail.
+  dest[0] = dest[1] = dest[2] = 0xff;
+  dest[3] = 0x00;
+  CHECK(!IsValidCompressedBuffer(TypeParam(dest)));
+  CHECK(!Uncompress(TypeParam(dest), &uncmp));
+
+  // try reading stuff in from a bad file.
+  for (int i = 1; i <= 3; ++i) {
+    string data = ReadTestDataFile(StringPrintf("baddata%d.snappy", i).c_str(),
+                                   0);
+    string uncmp;
+    // check that we don't return a crazy length
+    size_t ulen;
+    CHECK(!snappy::GetUncompressedLength(data.data(), data.size(), &ulen)
+          || (ulen < (1<<20)));
+    uint32 ulen2;
+    snappy::ByteArraySource source(data.data(), data.size());
+    CHECK(!snappy::GetUncompressedLength(&source, &ulen2) ||
+          (ulen2 < (1<<20)));
+    CHECK(!IsValidCompressedBuffer(TypeParam(data)));
+    CHECK(!Uncompress(TypeParam(data), &uncmp));
+  }
+}
+
+// Helper routines to construct arbitrary compressed strings.
+// These mirror the compression code in snappy.cc, but are copied
+// here so that we can bypass some limitations in the how snappy.cc
+// invokes these routines.
+static void AppendLiteral(string* dst, const string& literal) {
+  if (literal.empty()) return;
+  int n = literal.size() - 1;
+  if (n < 60) {
+    // Fit length in tag byte
+    dst->push_back(0 | (n << 2));
+  } else {
+    // Encode in upcoming bytes
+    char number[4];
+    int count = 0;
+    while (n > 0) {
+      number[count++] = n & 0xff;
+      n >>= 8;
+    }
+    dst->push_back(0 | ((59+count) << 2));
+    *dst += string(number, count);
+  }
+  *dst += literal;
+}
+
+static void AppendCopy(string* dst, int offset, int length) {
+  while (length > 0) {
+    // Figure out how much to copy in one shot
+    int to_copy;
+    if (length >= 68) {
+      to_copy = 64;
+    } else if (length > 64) {
+      to_copy = 60;
+    } else {
+      to_copy = length;
+    }
+    length -= to_copy;
+
+    if ((to_copy < 12) && (offset < 2048)) {
+      assert(to_copy-4 < 8);            // Must fit in 3 bits
+      dst->push_back(1 | ((to_copy-4) << 2) | ((offset >> 8) << 5));
+      dst->push_back(offset & 0xff);
+    } else if (offset < 65536) {
+      dst->push_back(2 | ((to_copy-1) << 2));
+      dst->push_back(offset & 0xff);
+      dst->push_back(offset >> 8);
+    } else {
+      dst->push_back(3 | ((to_copy-1) << 2));
+      dst->push_back(offset & 0xff);
+      dst->push_back((offset >> 8) & 0xff);
+      dst->push_back((offset >> 16) & 0xff);
+      dst->push_back((offset >> 24) & 0xff);
+    }
+  }
+}
+
+TEST(Snappy, SimpleTests) {
+  Verify("");
+  Verify("a");
+  Verify("ab");
+  Verify("abc");
+
+  Verify("aaaaaaa" + string(16, 'b') + string("aaaaa") + "abc");
+  Verify("aaaaaaa" + string(256, 'b') + string("aaaaa") + "abc");
+  Verify("aaaaaaa" + string(2047, 'b') + string("aaaaa") + "abc");
+  Verify("aaaaaaa" + string(65536, 'b') + string("aaaaa") + "abc");
+  Verify("abcaaaaaaa" + string(65536, 'b') + string("aaaaa") + "abc");
+}
+
+// Verify max blowup (lots of four-byte copies)
+TEST(Snappy, MaxBlowup) {
+  string input;
+  for (int i = 0; i < 20000; i++) {
+    ACMRandom rnd(i);
+    uint32 bytes = static_cast<uint32>(rnd.Next());
+    input.append(reinterpret_cast<char*>(&bytes), sizeof(bytes));
+  }
+  for (int i = 19999; i >= 0; i--) {
+    ACMRandom rnd(i);
+    uint32 bytes = static_cast<uint32>(rnd.Next());
+    input.append(reinterpret_cast<char*>(&bytes), sizeof(bytes));
+  }
+  Verify(input);
+}
+
+TEST(Snappy, RandomData) {
+  ACMRandom rnd(FLAGS_test_random_seed);
+
+  const int num_ops = 20000;
+  for (int i = 0; i < num_ops; i++) {
+    if ((i % 1000) == 0) {
+      VLOG(0) << "Random op " << i << " of " << num_ops;
+    }
+
+    string x;
+    int len = rnd.Uniform(4096);
+    if (i < 100) {
+      len = 65536 + rnd.Uniform(65536);
+    }
+    while (x.size() < len) {
+      int run_len = 1;
+      if (rnd.OneIn(10)) {
+        run_len = rnd.Skewed(8);
+      }
+      char c = (i < 100) ? rnd.Uniform(256) : rnd.Skewed(3);
+      while (run_len-- > 0 && x.size() < len) {
+        x += c;
+      }
+    }
+
+    Verify(x);
+  }
+}
+
+TEST(Snappy, FourByteOffset) {
+  // The new compressor cannot generate four-byte offsets since
+  // it chops up the input into 32KB pieces.  So we hand-emit the
+  // copy manually.
+
+  // The two fragments that make up the input string.
+  string fragment1 = "012345689abcdefghijklmnopqrstuvwxyz";
+  string fragment2 = "some other string";
+
+  // How many times each fragment is emitted.
+  const int n1 = 2;
+  const int n2 = 100000 / fragment2.size();
+  const int length = n1 * fragment1.size() + n2 * fragment2.size();
+
+  string compressed;
+  Varint::Append32(&compressed, length);
+
+  AppendLiteral(&compressed, fragment1);
+  string src = fragment1;
+  for (int i = 0; i < n2; i++) {
+    AppendLiteral(&compressed, fragment2);
+    src += fragment2;
+  }
+  AppendCopy(&compressed, src.size(), fragment1.size());
+  src += fragment1;
+  CHECK_EQ(length, src.size());
+
+  string uncompressed;
+  CHECK(snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+  CHECK(snappy::Uncompress(compressed.data(), compressed.size(),
+                           &uncompressed));
+  CHECK_EQ(uncompressed, src);
+}
+
+
+static bool CheckUncompressedLength(const string& compressed,
+                                    size_t* ulength) {
+  const bool result1 = snappy::GetUncompressedLength(compressed.data(),
+                                                     compressed.size(),
+                                                     ulength);
+
+  snappy::ByteArraySource source(compressed.data(), compressed.size());
+  uint32 length;
+  const bool result2 = snappy::GetUncompressedLength(&source, &length);
+  CHECK_EQ(result1, result2);
+  return result1;
+}
+
+TEST(SnappyCorruption, TruncatedVarint) {
+  string compressed, uncompressed;
+  size_t ulength;
+  compressed.push_back('\xf0');
+  CHECK(!CheckUncompressedLength(compressed, &ulength));
+  CHECK(!snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+  CHECK(!snappy::Uncompress(compressed.data(), compressed.size(),
+                            &uncompressed));
+}
+
+TEST(SnappyCorruption, UnterminatedVarint) {
+  string compressed, uncompressed;
+  size_t ulength;
+  compressed.push_back(128);
+  compressed.push_back(128);
+  compressed.push_back(128);
+  compressed.push_back(128);
+  compressed.push_back(128);
+  compressed.push_back(10);
+  CHECK(!CheckUncompressedLength(compressed, &ulength));
+  CHECK(!snappy::IsValidCompressedBuffer(compressed.data(), compressed.size()));
+  CHECK(!snappy::Uncompress(compressed.data(), compressed.size(),
+                            &uncompressed));
+}
+
+TEST(Snappy, ReadPastEndOfBuffer) {
+  // Check that we do not read past end of input
+
+  // Make a compressed string that ends with a single-byte literal
+  string compressed;
+  Varint::Append32(&compressed, 1);
+  AppendLiteral(&compressed, "x");
+
+  string uncompressed;
+  DataEndingAtUnreadablePage c(compressed);
+  CHECK(snappy::Uncompress(c.data(), c.size(), &uncompressed));
+  CHECK_EQ(uncompressed, string("x"));
+}
+
+// Check for an infinite loop caused by a copy with offset==0
+TEST(Snappy, ZeroOffsetCopy) {
+  const char* compressed = "\x40\x12\x00\x00";
+  //  \x40              Length (must be > kMaxIncrementCopyOverflow)
+  //  \x12\x00\x00      Copy with offset==0, length==5
+  char uncompressed[100];
+  EXPECT_FALSE(snappy::RawUncompress(compressed, 4, uncompressed));
+}
+
+TEST(Snappy, ZeroOffsetCopyValidation) {
+  const char* compressed = "\x05\x12\x00\x00";
+  //  \x05              Length
+  //  \x12\x00\x00      Copy with offset==0, length==5
+  EXPECT_FALSE(snappy::IsValidCompressedBuffer(compressed, 4));
+}
+
+
+namespace {
+
+int TestFindMatchLength(const char* s1, const char *s2, unsigned length) {
+  return snappy::internal::FindMatchLength(s1, s2, s2 + length);
+}
+
+}  // namespace
+
+TEST(Snappy, FindMatchLength) {
+  // Exercise all different code paths through the function.
+  // 64-bit version:
+
+  // Hit s1_limit in 64-bit loop, hit s1_limit in single-character loop.
+  EXPECT_EQ(6, TestFindMatchLength("012345", "012345", 6));
+  EXPECT_EQ(11, TestFindMatchLength("01234567abc", "01234567abc", 11));
+
+  // Hit s1_limit in 64-bit loop, find a non-match in single-character loop.
+  EXPECT_EQ(9, TestFindMatchLength("01234567abc", "01234567axc", 9));
+
+  // Same, but edge cases.
+  EXPECT_EQ(11, TestFindMatchLength("01234567abc!", "01234567abc!", 11));
+  EXPECT_EQ(11, TestFindMatchLength("01234567abc!", "01234567abc?", 11));
+
+  // Find non-match at once in first loop.
+  EXPECT_EQ(0, TestFindMatchLength("01234567xxxxxxxx", "?1234567xxxxxxxx", 16));
+  EXPECT_EQ(1, TestFindMatchLength("01234567xxxxxxxx", "0?234567xxxxxxxx", 16));
+  EXPECT_EQ(4, TestFindMatchLength("01234567xxxxxxxx", "01237654xxxxxxxx", 16));
+  EXPECT_EQ(7, TestFindMatchLength("01234567xxxxxxxx", "0123456?xxxxxxxx", 16));
+
+  // Find non-match in first loop after one block.
+  EXPECT_EQ(8, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+                                   "abcdefgh?1234567xxxxxxxx", 24));
+  EXPECT_EQ(9, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+                                   "abcdefgh0?234567xxxxxxxx", 24));
+  EXPECT_EQ(12, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+                                    "abcdefgh01237654xxxxxxxx", 24));
+  EXPECT_EQ(15, TestFindMatchLength("abcdefgh01234567xxxxxxxx",
+                                    "abcdefgh0123456?xxxxxxxx", 24));
+
+  // 32-bit version:
+
+  // Short matches.
+  EXPECT_EQ(0, TestFindMatchLength("01234567", "?1234567", 8));
+  EXPECT_EQ(1, TestFindMatchLength("01234567", "0?234567", 8));
+  EXPECT_EQ(2, TestFindMatchLength("01234567", "01?34567", 8));
+  EXPECT_EQ(3, TestFindMatchLength("01234567", "012?4567", 8));
+  EXPECT_EQ(4, TestFindMatchLength("01234567", "0123?567", 8));
+  EXPECT_EQ(5, TestFindMatchLength("01234567", "01234?67", 8));
+  EXPECT_EQ(6, TestFindMatchLength("01234567", "012345?7", 8));
+  EXPECT_EQ(7, TestFindMatchLength("01234567", "0123456?", 8));
+  EXPECT_EQ(7, TestFindMatchLength("01234567", "0123456?", 7));
+  EXPECT_EQ(7, TestFindMatchLength("01234567!", "0123456??", 7));
+
+  // Hit s1_limit in 32-bit loop, hit s1_limit in single-character loop.
+  EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd", "xxxxxxabcd", 10));
+  EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd?", "xxxxxxabcd?", 10));
+  EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcdef", "xxxxxxabcdef", 13));
+
+  // Same, but edge cases.
+  EXPECT_EQ(12, TestFindMatchLength("xxxxxx0123abc!", "xxxxxx0123abc!", 12));
+  EXPECT_EQ(12, TestFindMatchLength("xxxxxx0123abc!", "xxxxxx0123abc?", 12));
+
+  // Hit s1_limit in 32-bit loop, find a non-match in single-character loop.
+  EXPECT_EQ(11, TestFindMatchLength("xxxxxx0123abc", "xxxxxx0123axc", 13));
+
+  // Find non-match at once in first loop.
+  EXPECT_EQ(6, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+                                   "xxxxxx?123xxxxxxxx", 18));
+  EXPECT_EQ(7, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+                                   "xxxxxx0?23xxxxxxxx", 18));
+  EXPECT_EQ(8, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+                                   "xxxxxx0132xxxxxxxx", 18));
+  EXPECT_EQ(9, TestFindMatchLength("xxxxxx0123xxxxxxxx",
+                                   "xxxxxx012?xxxxxxxx", 18));
+
+  // Same, but edge cases.
+  EXPECT_EQ(6, TestFindMatchLength("xxxxxx0123", "xxxxxx?123", 10));
+  EXPECT_EQ(7, TestFindMatchLength("xxxxxx0123", "xxxxxx0?23", 10));
+  EXPECT_EQ(8, TestFindMatchLength("xxxxxx0123", "xxxxxx0132", 10));
+  EXPECT_EQ(9, TestFindMatchLength("xxxxxx0123", "xxxxxx012?", 10));
+
+  // Find non-match in first loop after one block.
+  EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd0123xx",
+                                    "xxxxxxabcd?123xx", 16));
+  EXPECT_EQ(11, TestFindMatchLength("xxxxxxabcd0123xx",
+                                    "xxxxxxabcd0?23xx", 16));
+  EXPECT_EQ(12, TestFindMatchLength("xxxxxxabcd0123xx",
+                                    "xxxxxxabcd0132xx", 16));
+  EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcd0123xx",
+                                    "xxxxxxabcd012?xx", 16));
+
+  // Same, but edge cases.
+  EXPECT_EQ(10, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd?123", 14));
+  EXPECT_EQ(11, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd0?23", 14));
+  EXPECT_EQ(12, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd0132", 14));
+  EXPECT_EQ(13, TestFindMatchLength("xxxxxxabcd0123", "xxxxxxabcd012?", 14));
+}
+
+TEST(Snappy, FindMatchLengthRandom) {
+  const int kNumTrials = 10000;
+  const int kTypicalLength = 10;
+  ACMRandom rnd(FLAGS_test_random_seed);
+
+  for (int i = 0; i < kNumTrials; i++) {
+    string s, t;
+    char a = rnd.Rand8();
+    char b = rnd.Rand8();
+    while (!rnd.OneIn(kTypicalLength)) {
+      s.push_back(rnd.OneIn(2) ? a : b);
+      t.push_back(rnd.OneIn(2) ? a : b);
+    }
+    DataEndingAtUnreadablePage u(s);
+    DataEndingAtUnreadablePage v(t);
+    int matched = snappy::internal::FindMatchLength(
+        u.data(), v.data(), v.data() + t.size());
+    if (matched == t.size()) {
+      EXPECT_EQ(s, t);
+    } else {
+      EXPECT_NE(s[matched], t[matched]);
+      for (int j = 0; j < matched; j++) {
+        EXPECT_EQ(s[j], t[j]);
+      }
+    }
+  }
+}
+
+
+static void CompressFile(const char* fname) {
+  string fullinput;
+  file::GetContents(fname, &fullinput, file::Defaults()).CheckSuccess();
+
+  string compressed;
+  Compress(fullinput.data(), fullinput.size(), SNAPPY, &compressed, false);
+
+  file::SetContents(string(fname).append(".comp"), compressed, file::Defaults())
+      .CheckSuccess();
+}
+
+static void UncompressFile(const char* fname) {
+  string fullinput;
+  file::GetContents(fname, &fullinput, file::Defaults()).CheckSuccess();
+
+  size_t uncompLength;
+  CHECK(CheckUncompressedLength(fullinput, &uncompLength));
+
+  string uncompressed;
+  uncompressed.resize(uncompLength);
+  CHECK(snappy::Uncompress(fullinput.data(), fullinput.size(), &uncompressed));
+
+  file::SetContents(string(fname).append(".uncomp"), uncompressed,
+                    file::Defaults()).CheckSuccess();
+}
+
+static void MeasureFile(const char* fname) {
+  string fullinput;
+  file::GetContents(fname, &fullinput, file::Defaults()).CheckSuccess();
+  printf("%-40s :\n", fname);
+
+  int start_len = (FLAGS_start_len < 0) ? fullinput.size() : FLAGS_start_len;
+  int end_len = fullinput.size();
+  if (FLAGS_end_len >= 0) {
+    end_len = min<int>(fullinput.size(), FLAGS_end_len);
+  }
+  for (int len = start_len; len <= end_len; len++) {
+    const char* const input = fullinput.data();
+    int repeats = (FLAGS_bytes + len) / (len + 1);
+    if (FLAGS_zlib)     Measure(input, len, ZLIB, repeats, 1024<<10);
+    if (FLAGS_lzo)      Measure(input, len, LZO, repeats, 1024<<10);
+    if (FLAGS_liblzf)   Measure(input, len, LIBLZF, repeats, 1024<<10);
+    if (FLAGS_quicklz)  Measure(input, len, QUICKLZ, repeats, 1024<<10);
+    if (FLAGS_fastlz)   Measure(input, len, FASTLZ, repeats, 1024<<10);
+    if (FLAGS_snappy)    Measure(input, len, SNAPPY, repeats, 4096<<10);
+
+    // For block-size based measurements
+    if (0 && FLAGS_snappy) {
+      Measure(input, len, SNAPPY, repeats, 8<<10);
+      Measure(input, len, SNAPPY, repeats, 16<<10);
+      Measure(input, len, SNAPPY, repeats, 32<<10);
+      Measure(input, len, SNAPPY, repeats, 64<<10);
+      Measure(input, len, SNAPPY, repeats, 256<<10);
+      Measure(input, len, SNAPPY, repeats, 1024<<10);
+    }
+  }
+}
+
+static struct {
+  const char* label;
+  const char* filename;
+  size_t size_limit;
+} files[] = {
+  { "html", "html", 0 },
+  { "urls", "urls.10K", 0 },
+  { "jpg", "house.jpg", 0 },
+  { "jpg_200", "house.jpg", 200 },
+  { "pdf", "mapreduce-osdi-1.pdf", 0 },
+  { "html4", "html_x_4", 0 },
+  { "cp", "cp.html", 0 },
+  { "c", "fields.c", 0 },
+  { "lsp", "grammar.lsp", 0 },
+  { "xls", "kennedy.xls", 0 },
+  { "xls_200", "kennedy.xls", 200 },
+  { "txt1", "alice29.txt", 0 },
+  { "txt2", "asyoulik.txt", 0 },
+  { "txt3", "lcet10.txt", 0 },
+  { "txt4", "plrabn12.txt", 0 },
+  { "bin", "ptt5", 0 },
+  { "bin_200", "ptt5", 200 },
+  { "sum", "sum", 0 },
+  { "man", "xargs.1", 0 },
+  { "pb", "geo.protodata", 0 },
+  { "gaviota", "kppkn.gtb", 0 },
+};
+
+static void BM_UFlat(int iters, int arg) {
+  StopBenchmarkTiming();
+
+  // Pick file to process based on "arg"
+  CHECK_GE(arg, 0);
+  CHECK_LT(arg, ARRAYSIZE(files));
+  string contents = ReadTestDataFile(files[arg].filename,
+                                     files[arg].size_limit);
+
+  string zcontents;
+  snappy::Compress(contents.data(), contents.size(), &zcontents);
+  char* dst = new char[contents.size()];
+
+  SetBenchmarkBytesProcessed(static_cast<int64>(iters) *
+                             static_cast<int64>(contents.size()));
+  SetBenchmarkLabel(files[arg].label);
+  StartBenchmarkTiming();
+  while (iters-- > 0) {
+    CHECK(snappy::RawUncompress(zcontents.data(), zcontents.size(), dst));
+  }
+  StopBenchmarkTiming();
+
+  delete[] dst;
+}
+BENCHMARK(BM_UFlat)->DenseRange(0, ARRAYSIZE(files) - 1);
+
+static void BM_UValidate(int iters, int arg) {
+  StopBenchmarkTiming();
+
+  // Pick file to process based on "arg"
+  CHECK_GE(arg, 0);
+  CHECK_LT(arg, ARRAYSIZE(files));
+  string contents = ReadTestDataFile(files[arg].filename,
+                                     files[arg].size_limit);
+
+  string zcontents;
+  snappy::Compress(contents.data(), contents.size(), &zcontents);
+
+  SetBenchmarkBytesProcessed(static_cast<int64>(iters) *
+                             static_cast<int64>(contents.size()));
+  SetBenchmarkLabel(files[arg].label);
+  StartBenchmarkTiming();
+  while (iters-- > 0) {
+    CHECK(snappy::IsValidCompressedBuffer(zcontents.data(), zcontents.size()));
+  }
+  StopBenchmarkTiming();
+}
+BENCHMARK(BM_UValidate)->DenseRange(0, 4);
+
+
+static void BM_ZFlat(int iters, int arg) {
+  StopBenchmarkTiming();
+
+  // Pick file to process based on "arg"
+  CHECK_GE(arg, 0);
+  CHECK_LT(arg, ARRAYSIZE(files));
+  string contents = ReadTestDataFile(files[arg].filename,
+                                     files[arg].size_limit);
+
+  char* dst = new char[snappy::MaxCompressedLength(contents.size())];
+
+  SetBenchmarkBytesProcessed(static_cast<int64>(iters) *
+                             static_cast<int64>(contents.size()));
+  StartBenchmarkTiming();
+
+  size_t zsize = 0;
+  while (iters-- > 0) {
+    snappy::RawCompress(contents.data(), contents.size(), dst, &zsize);
+  }
+  StopBenchmarkTiming();
+  const double compression_ratio =
+      static_cast<double>(zsize) / std::max<size_t>(1, contents.size());
+  SetBenchmarkLabel(StringPrintf("%s (%.2f %%)",
+                                 files[arg].label, 100.0 * compression_ratio));
+  VLOG(0) << StringPrintf("compression for %s: %zd -> %zd bytes",
+                          files[arg].label, contents.size(), zsize);
+  delete[] dst;
+}
+BENCHMARK(BM_ZFlat)->DenseRange(0, ARRAYSIZE(files) - 1);
+
+
+}  // namespace snappy
+
+
+int main(int argc, char** argv) {
+  InitGoogle(argv[0], &argc, &argv, true);
+  File::Init();
+  RunSpecifiedBenchmarks();
+
+
+  if (argc >= 2) {
+    for (int arg = 1; arg < argc; arg++) {
+      if (FLAGS_write_compressed) {
+        CompressFile(argv[arg]);
+      } else if (FLAGS_write_uncompressed) {
+        UncompressFile(argv[arg]);
+      } else {
+        MeasureFile(argv[arg]);
+      }
+    }
+    return 0;
+  }
+
+  return RUN_ALL_TESTS();
+}