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authorArne Schwabe <arne@rfc2549.org>2012-04-16 19:21:14 +0200
committerArne Schwabe <arne@rfc2549.org>2012-04-16 19:21:14 +0200
commit3e4d8f433239c40311037616b1b8833a06651ae0 (patch)
tree98ab7fce0d011d34677b0beb762d389cb5c39199 /lzo/src/lzo2a_9x.c
Initial import
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+/* lzo2a_9x.c -- implementation of the LZO2A-999 compression algorithm
+
+ This file is part of the LZO real-time data compression library.
+
+ Copyright (C) 2008 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2007 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2006 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2005 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2004 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2003 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2002 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2001 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 2000 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 1999 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 1998 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 1997 Markus Franz Xaver Johannes Oberhumer
+ Copyright (C) 1996 Markus Franz Xaver Johannes Oberhumer
+ All Rights Reserved.
+
+ The LZO library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License as
+ published by the Free Software Foundation; either version 2 of
+ the License, or (at your option) any later version.
+
+ The LZO library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with the LZO library; see the file COPYING.
+ If not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ Markus F.X.J. Oberhumer
+ <markus@oberhumer.com>
+ http://www.oberhumer.com/opensource/lzo/
+ */
+
+
+
+#include "config2a.h"
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+#define THRESHOLD 1 /* lower limit for match length */
+#define F 2048 /* upper limit for match length */
+
+
+#define LZO2A
+#define LZO_COMPRESS_T lzo2a_999_t
+#define lzo_swd_t lzo2a_999_swd_t
+#include "lzo_mchw.ch"
+
+
+#if (LZO_CC_BORLANDC && LZO_MM_FLAT)
+# if ((__BORLANDC__) >= 0x0450 && (__BORLANDC__) < 0x0460)
+ /* avoid internal compiler error */
+# pragma option -Od
+# endif
+#endif
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+#define putbyte(x) *op++ = LZO_BYTE(x)
+
+#define putbits(j,x) \
+ if (k == 0) bitp = op++; \
+ SETBITS(j,x); \
+ if (k >= 8) { *bitp = LZO_BYTE(MASKBITS(8)); DUMPBITS(8); \
+ if (k > 0) bitp = op++; }
+
+#define putbit(x) putbits(1,x)
+
+
+/***********************************************************************
+// this is a public function, but there is no prototype in a header file
+************************************************************************/
+
+LZO_EXTERN(int)
+lzo2a_999_compress_callback ( const lzo_bytep in , lzo_uint in_len,
+ lzo_bytep out, lzo_uintp out_len,
+ lzo_voidp wrkmem,
+ lzo_callback_p cb,
+ lzo_uint max_chain );
+
+LZO_PUBLIC(int)
+lzo2a_999_compress_callback ( const lzo_bytep in , lzo_uint in_len,
+ lzo_bytep out, lzo_uintp out_len,
+ lzo_voidp wrkmem,
+ lzo_callback_p cb,
+ lzo_uint max_chain )
+{
+ lzo_bytep op;
+ lzo_bytep bitp = 0;
+ lzo_uint m_len, m_off;
+ LZO_COMPRESS_T cc;
+ LZO_COMPRESS_T * const c = &cc;
+ lzo_swd_p const swd = (lzo_swd_p) wrkmem;
+ int r;
+
+ lzo_uint32 b = 0; /* bit buffer */
+ unsigned k = 0; /* bits in bit buffer */
+
+ /* sanity check */
+ LZO_COMPILE_TIME_ASSERT(LZO2A_999_MEM_COMPRESS >= SIZEOF_LZO_SWD_T)
+
+ c->init = 0;
+ c->ip = c->in = in;
+ c->in_end = in + in_len;
+ c->cb = cb;
+ c->m1 = c->m2 = c->m3 = c->m4 = 0;
+
+ op = out;
+
+ r = init_match(c,swd,NULL,0,0);
+ if (r != 0)
+ return r;
+ if (max_chain > 0)
+ swd->max_chain = max_chain;
+
+ r = find_match(c,swd,0,0);
+ if (r != 0)
+ return r;
+ while (c->look > 0)
+ {
+ int lazy_match_min_gain = 0;
+ int extra1 = 0;
+ int extra2 = 0;
+ lzo_uint ahead = 0;
+
+ LZO_UNUSED(extra1);
+
+ m_len = c->m_len;
+ m_off = c->m_off;
+
+#if (N >= 8192)
+ if (m_off >= 8192)
+ {
+ if (m_len < M3_MIN_LEN)
+ m_len = 0;
+ else
+ lazy_match_min_gain = 1;
+ }
+ else
+#endif
+ if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
+ {
+ lazy_match_min_gain = 2;
+ extra1 = 3;
+ extra2 = 2;
+ }
+ else if (m_len >= 10)
+ lazy_match_min_gain = 1;
+ else if (m_len >= 3)
+ {
+ lazy_match_min_gain = 1;
+ extra1 = 1;
+ }
+ else
+ m_len = 0;
+
+
+ /* try a lazy match */
+ if (lazy_match_min_gain > 0 && c->look > m_len)
+ {
+ int lit = swd->b_char;
+
+ r = find_match(c,swd,1,0);
+ assert(r == 0);
+ assert(c->look > 0);
+
+#if (N >= 8192)
+ if (m_off < 8192 && c->m_off >= 8192)
+ lazy_match_min_gain += extra1;
+ else
+#endif
+ if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
+ {
+ if (!(c->m_len >= M1_MIN_LEN &&
+ c->m_len <= M1_MAX_LEN && c->m_off <= 256))
+ lazy_match_min_gain += extra2;
+ }
+ if (c->m_len >= M1_MIN_LEN &&
+ c->m_len <= M1_MAX_LEN && c->m_off <= 256)
+ {
+ lazy_match_min_gain -= 1;
+ }
+
+ if (lazy_match_min_gain < 1)
+ lazy_match_min_gain = 1;
+
+ if (c->m_len >= m_len + lazy_match_min_gain)
+ {
+ c->lazy++;
+#if !defined(NDEBUG)
+ m_len = c->m_len;
+ m_off = c->m_off;
+ assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
+ m_len) == 0);
+ assert(m_len >= 3 || (m_len >= 2 && m_off <= 256));
+#endif
+ /* code literal */
+ putbit(0);
+ putbyte(lit);
+ c->lit_bytes++;
+ continue;
+ }
+ else
+ ahead = 1;
+ assert(m_len > 0);
+ }
+
+
+ if (m_len == 0)
+ {
+ /* a literal */
+ putbit(0);
+ putbyte(swd->b_char);
+ c->lit_bytes++;
+ r = find_match(c,swd,1,0);
+ assert(r == 0);
+ }
+ else
+ {
+ assert(m_len >= M1_MIN_LEN);
+ assert(m_off > 0);
+ assert(m_off <= N);
+
+ /* 2 - code match */
+ if (m_len >= M1_MIN_LEN && m_len <= M1_MAX_LEN && m_off <= 256)
+ {
+ putbit(1);
+ putbit(0);
+ putbits(2,m_len - M1_MIN_LEN);
+ putbyte(m_off - 1);
+ c->m1++;
+ }
+#if (N >= 8192)
+ else if (m_off >= 8192)
+ {
+ unsigned len = m_len;
+ assert(m_len >= M3_MIN_LEN);
+ putbit(1);
+ putbit(1);
+ putbyte(m_off & 31);
+ putbyte(m_off >> 5);
+ putbit(1);
+ len -= M3_MIN_LEN - 1;
+ while (len > 255)
+ {
+ len -= 255;
+ putbyte(0);
+ }
+ putbyte(len);
+ c->m4++;
+ }
+#endif
+ else
+ {
+ assert(m_len >= 3);
+
+ putbit(1);
+ putbit(1);
+ if (m_len <= 9)
+ {
+ putbyte(((m_len - 2) << 5) | (m_off & 31));
+ putbyte(m_off >> 5);
+ c->m2++;
+ }
+ else
+ {
+ lzo_uint len = m_len;
+ putbyte(m_off & 31);
+ putbyte(m_off >> 5);
+#if (N >= 8192)
+ putbit(0);
+#endif
+ len -= 10 - 1;
+ while (len > 255)
+ {
+ len -= 255;
+ putbyte(0);
+ }
+ putbyte(len);
+ c->m3++;
+ }
+ }
+ r = find_match(c,swd,m_len,1+ahead);
+ assert(r == 0);
+ }
+
+ c->codesize = pd(op, out);
+ }
+
+#if defined(LZO_EOF_CODE)
+ /* code EOF code */
+ putbit(1);
+ putbit(1);
+ putbyte(1 << 5);
+ putbyte(0);
+#endif
+
+ /* flush remaining bits */
+ assert(k < CHAR_BIT);
+ if (k > 0)
+ {
+ assert(b == MASKBITS(k));
+ assert(op - bitp > 1);
+ *bitp = LZO_BYTE(MASKBITS(k));
+ DUMPBITS(k);
+ assert(b == 0);
+ assert(k == 0);
+ }
+
+ assert(c->textsize == in_len);
+ c->codesize = pd(op, out);
+
+ *out_len = pd(op, out);
+
+ if (c->cb && c->cb->nprogress)
+ (*c->cb->nprogress)(c->cb, c->textsize, c->codesize, 0);
+
+#if 0
+ printf("%ld -> %ld: %ld %ld %ld %ld %ld %ld\n",
+ (long) c->textsize, (long) c->codesize,
+ c->lit_bytes, c->m1, c->m2, c->m3, c->m4, c->lazy);
+#endif
+ return LZO_E_OK;
+}
+
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+LZO_PUBLIC(int)
+lzo2a_999_compress ( const lzo_bytep in , lzo_uint in_len,
+ lzo_bytep out, lzo_uintp out_len,
+ lzo_voidp wrkmem )
+{
+ return lzo2a_999_compress_callback(in,in_len,out,out_len,wrkmem,
+ (lzo_callback_p) 0, 0);
+}
+
+
+/*
+vi:ts=4:et
+*/
+