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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/lzo1f_9x.c
Initial import
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+/* lzo1f_9x.c -- implementation of the LZO1F-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 "config1f.h"
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+#define N 16383 /* size of ring buffer */
+#define THRESHOLD 2 /* lower limit for match length */
+#define F 2048 /* upper limit for match length */
+
+
+#define LZO1F
+#define LZO_COMPRESS_T lzo1f_999_t
+#define lzo_swd_t lzo1f_999_swd_t
+#include "lzo_mchw.ch"
+
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+static lzo_bytep
+code_match ( LZO_COMPRESS_T *c, lzo_bytep op, lzo_uint m_len, lzo_uint m_off )
+{
+ if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET)
+ {
+ m_off -= 1;
+ *op++ = LZO_BYTE(((m_len - 2) << 5) | ((m_off & 7) << 2));
+ *op++ = LZO_BYTE(m_off >> 3);
+ c->m2_m++;
+ }
+ else if (m_len == M2_MIN_LEN && m_off <= 2 * M2_MAX_OFFSET &&
+ c->r1_lit > 0)
+ {
+ assert(m_off > M2_MAX_OFFSET);
+ m_off -= 1 + M2_MAX_OFFSET;
+ *op++ = LZO_BYTE(((m_off & 7) << 2));
+ *op++ = LZO_BYTE(m_off >> 3);
+ c->r1_r++;
+ }
+ else
+ {
+ if (m_len <= M3_MAX_LEN)
+ *op++ = LZO_BYTE(M3_MARKER | (m_len - 2));
+ else
+ {
+ m_len -= M3_MAX_LEN;
+ *op++ = M3_MARKER | 0;
+ while (m_len > 255)
+ {
+ m_len -= 255;
+ *op++ = 0;
+ }
+ assert(m_len > 0);
+ *op++ = LZO_BYTE(m_len);
+ }
+ *op++ = LZO_BYTE((m_off & 63) << 2);
+ *op++ = LZO_BYTE(m_off >> 6);
+ c->m3_m++;
+ }
+
+ return op;
+}
+
+
+static lzo_bytep
+STORE_RUN ( lzo_bytep op, const lzo_bytep ii, lzo_uint t, lzo_bytep out )
+{
+ if (t < 4 && op > out)
+ op[-2] |= LZO_BYTE(t);
+ else if (t <= 31)
+ *op++ = LZO_BYTE(t);
+ else
+ {
+ lzo_uint tt = t - 31;
+
+ *op++ = 0;
+ while (tt > 255)
+ {
+ tt -= 255;
+ *op++ = 0;
+ }
+ assert(tt > 0);
+ *op++ = LZO_BYTE(tt);
+ }
+ do *op++ = *ii++; while (--t > 0);
+
+ return op;
+}
+
+
+/***********************************************************************
+// this is a public function, but there is no prototype in a header file
+************************************************************************/
+
+LZO_EXTERN(int)
+lzo1f_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)
+lzo1f_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;
+ const lzo_bytep ii;
+ lzo_uint lit;
+ 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;
+
+ /* sanity check */
+ LZO_COMPILE_TIME_ASSERT(LZO1F_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->r1_r = c->m2_m = c->m3_m = 0;
+
+ op = out;
+ ii = c->ip; /* point to start of literal run */
+ lit = 0;
+ c->r1_lit = c->r1_m_len = 0;
+
+ 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 = -1;
+ lzo_uint ahead = 0;
+
+ m_len = c->m_len;
+ m_off = c->m_off;
+
+ assert(c->ip - c->look >= in);
+ if (lit == 0)
+ ii = c->ip - c->look;
+ assert(ii + lit == c->ip - c->look);
+ assert(swd->b_char == *(c->ip - c->look));
+
+ if ((m_len < M2_MIN_LEN) ||
+ (m_len < M3_MIN_LEN && m_off > M2_MAX_OFFSET))
+ {
+ m_len = 0;
+ }
+ else
+ {
+ assert(c->ip - c->look - m_off >= in);
+ assert(c->ip - c->look - m_off + m_len < c->ip);
+ assert(lzo_memcmp(c->ip - c->look, c->ip - c->look - m_off,
+ m_len) == 0);
+
+ if (lit < 3)
+ lazy_match_min_gain = 1;
+ else if (lit == 3)
+ lazy_match_min_gain = 3;
+ else if (lit == 31)
+ lazy_match_min_gain = 3;
+ else
+ lazy_match_min_gain = 1;
+ }
+
+ /* try a lazy match */
+ if (m_len > 0 && lazy_match_min_gain >= 0 && c->look > m_len)
+ {
+ r = find_match(c,swd,1,0);
+ assert(r == 0);
+ assert(c->look > 0);
+
+ if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET &&
+ c->m_off > M2_MAX_OFFSET)
+ {
+ lazy_match_min_gain += 1;
+ }
+ else if (c->m_len <= M2_MAX_LEN &&
+ c->m_off <= M2_MAX_OFFSET &&
+ m_off > M2_MAX_OFFSET)
+ {
+ if (lazy_match_min_gain > 0)
+ lazy_match_min_gain -= 1;
+ }
+ else if (m_len == M2_MIN_LEN && c->m_len == M2_MIN_LEN &&
+ c->m_off <= 2 * M2_MAX_OFFSET &&
+ m_off > M2_MAX_OFFSET)
+ {
+ if (lazy_match_min_gain > 0)
+ 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);
+#endif
+ lit++;
+ assert(ii + lit == c->ip - c->look);
+ continue;
+ }
+ else
+ {
+ ahead = 1;
+ assert(ii + lit + 1 == c->ip - c->look);
+ }
+ assert(m_len > 0);
+ }
+ assert(ii + lit + ahead == c->ip - c->look);
+
+
+ if (m_len == 0)
+ {
+ /* a literal */
+ lit++;
+ r = find_match(c,swd,1,0);
+ assert(r == 0);
+ }
+ else
+ {
+ /* 1 - store run */
+ if (lit > 0)
+ {
+ op = STORE_RUN(op,ii,lit,out);
+ c->r1_m_len = m_len;
+ c->r1_lit = lit;
+ lit = 0;
+ }
+ else
+ c->r1_lit = c->r1_m_len = 0;
+
+ /* 2 - code match */
+ op = code_match(c,op,m_len,m_off);
+ r = find_match(c,swd,m_len,1+ahead);
+ assert(r == 0);
+ }
+
+ c->codesize = pd(op, out);
+ }
+
+
+ /* store final run */
+ if (lit > 0)
+ op = STORE_RUN(op,ii,lit,out);
+
+#if defined(LZO_EOF_CODE)
+ *op++ = M3_MARKER | 1;
+ *op++ = 0;
+ *op++ = 0;
+#endif
+
+ c->codesize = pd(op, out);
+ assert(c->textsize == in_len);
+
+ *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\n",
+ (long) c->textsize, (long)in_len, (long) c->codesize,
+ c->r1_r, c->m2_m, c->m3_m, c->lazy);
+#endif
+ return LZO_E_OK;
+}
+
+
+
+/***********************************************************************
+//
+************************************************************************/
+
+LZO_PUBLIC(int)
+lzo1f_999_compress ( const lzo_bytep in , lzo_uint in_len,
+ lzo_bytep out, lzo_uintp out_len,
+ lzo_voidp wrkmem )
+{
+ return lzo1f_999_compress_callback(in,in_len,out,out_len,wrkmem,
+ (lzo_callback_p) 0, 0);
+}
+
+
+/*
+vi:ts=4:et
+*/
+