mchapman/zlib
1
0
Fork 0
Code Issues Pull Requests Projects Releases Wiki Activity

zlib 1.2.3.5

Browse Source
This commit is contained in:
Mark Adler
2011-09-09 23:26:49 -07:00
parent f6194ef39a
commit d004b04783
74 changed files with 7130 additions and 1865 deletions
Download Patch File Download Diff File Expand all files Collapse all files

139
deflate.c
View File

@@ -1,5 +1,5 @@
/* deflate.c -- compress data using the deflation algorithm
* Copyright (C) 1995-2009 Jean-loup Gailly.
* Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
* For conditions of distribution and use, see copyright notice in zlib.h
*/
@@ -52,7 +52,7 @@
#include "deflate.h"
const char deflate_copyright[] =
" deflate 1.2.3.4 Copyright 1995-2009 Jean-loup Gailly ";
" deflate 1.2.3.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";
/*
If you use the zlib library in a product, an acknowledgment is welcome
in the documentation of your product. If for some reason you cannot
@@ -79,19 +79,18 @@ local block_state deflate_fast OF((deflate_state *s, int flush));
#ifndef FASTEST
local block_state deflate_slow OF((deflate_state *s, int flush));
#endif
local block_state deflate_rle OF((deflate_state *s, int flush));
local block_state deflate_huff OF((deflate_state *s, int flush));
local void lm_init OF((deflate_state *s));
local void putShortMSB OF((deflate_state *s, uInt b));
local void flush_pending OF((z_streamp strm));
local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
#ifndef FASTEST
#ifdef ASMV
void match_init OF((void)); /* asm code initialization */
uInt longest_match OF((deflate_state *s, IPos cur_match));
#else
local uInt longest_match OF((deflate_state *s, IPos cur_match));
#endif
#endif
local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
#ifdef DEBUG
local void check_match OF((deflate_state *s, IPos start, IPos match,
@@ -432,9 +431,10 @@ int ZEXPORT deflateParams(strm, level, strategy)
}
func = configuration_table[s->level].func;
if (func != configuration_table[level].func && strm->total_in != 0) {
if ((strategy != s->strategy || func != configuration_table[level].func) &&
strm->total_in != 0) {
/* Flush the last buffer: */
err = deflate(strm, Z_PARTIAL_FLUSH);
err = deflate(strm, Z_BLOCK);
}
if (s->level != level) {
s->level = level;
@@ -536,7 +536,8 @@ uLong ZEXPORT deflateBound(strm, sourceLen)
return complen + wraplen;
/* default settings: return tight bound for that case */
return compressBound(sourceLen) - 6 + wraplen;
return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
(sourceLen >> 25) + 13 - 6 + wraplen;
}
/* =========================================================================
@@ -816,7 +817,9 @@ int ZEXPORT deflate (strm, flush)
(flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
block_state bstate;
bstate = (*(configuration_table[s->level].func))(s, flush);
bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
(s->strategy == Z_RLE ? deflate_rle(s, flush) :
(*(configuration_table[s->level].func))(s, flush));
if (bstate == finish_started || bstate == finish_done) {
s->status = FINISH_STATE;
@@ -1200,12 +1203,13 @@ local uInt longest_match(s, cur_match)
return s->lookahead;
}
#endif /* ASMV */
#endif /* FASTEST */
#else /* FASTEST */
/* ---------------------------------------------------------------------------
* Optimized version for level == 1 or strategy == Z_RLE only
* Optimized version for FASTEST only
*/
local uInt longest_match_fast(s, cur_match)
local uInt longest_match(s, cur_match)
deflate_state *s;
IPos cur_match; /* current match */
{
@@ -1258,6 +1262,8 @@ local uInt longest_match_fast(s, cur_match)
return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
}
#endif /* FASTEST */
#ifdef DEBUG
/* ===========================================================================
* Check that the match at match_start is indeed a match.
@@ -1336,7 +1342,6 @@ local void fill_window(s)
later. (Using level 0 permanently is not an optimal usage of
zlib, so we don't care about this pathological case.)
*/
/* %%% avoid this when Z_RLE */
n = s->hash_size;
p = &s->head[n];
do {
@@ -1516,7 +1521,7 @@ local block_state deflate_fast(s, flush)
deflate_state *s;
int flush;
{
IPos hash_head = NIL; /* head of the hash chain */
IPos hash_head; /* head of the hash chain */
int bflush; /* set if current block must be flushed */
for (;;) {
@@ -1536,6 +1541,7 @@ local block_state deflate_fast(s, flush)
/* Insert the string window[strstart .. strstart+2] in the
* dictionary, and set hash_head to the head of the hash chain:
*/
hash_head = NIL;
if (s->lookahead >= MIN_MATCH) {
INSERT_STRING(s, s->strstart, hash_head);
}
@@ -1548,19 +1554,8 @@ local block_state deflate_fast(s, flush)
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
*/
#ifdef FASTEST
if ((s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) ||
(s->strategy == Z_RLE && s->strstart - hash_head == 1)) {
s->match_length = longest_match_fast (s, hash_head);
}
#else
if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
s->match_length = longest_match (s, hash_head);
} else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
s->match_length = longest_match_fast (s, hash_head);
}
#endif
/* longest_match() or longest_match_fast() sets match_start */
s->match_length = longest_match (s, hash_head);
/* longest_match() sets match_start */
}
if (s->match_length >= MIN_MATCH) {
check_match(s, s->strstart, s->match_start, s->match_length);
@@ -1622,7 +1617,7 @@ local block_state deflate_slow(s, flush)
deflate_state *s;
int flush;
{
IPos hash_head = NIL; /* head of hash chain */
IPos hash_head; /* head of hash chain */
int bflush; /* set if current block must be flushed */
/* Process the input block. */
@@ -1643,6 +1638,7 @@ local block_state deflate_slow(s, flush)
/* Insert the string window[strstart .. strstart+2] in the
* dictionary, and set hash_head to the head of the hash chain:
*/
hash_head = NIL;
if (s->lookahead >= MIN_MATCH) {
INSERT_STRING(s, s->strstart, hash_head);
}
@@ -1658,12 +1654,8 @@ local block_state deflate_slow(s, flush)
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
*/
if (s->strategy != Z_HUFFMAN_ONLY && s->strategy != Z_RLE) {
s->match_length = longest_match (s, hash_head);
} else if (s->strategy == Z_RLE && s->strstart - hash_head == 1) {
s->match_length = longest_match_fast (s, hash_head);
}
/* longest_match() or longest_match_fast() sets match_start */
s->match_length = longest_match (s, hash_head);
/* longest_match() sets match_start */
if (s->match_length <= 5 && (s->strategy == Z_FILTERED
#if TOO_FAR <= 32767
@@ -1741,7 +1733,6 @@ local block_state deflate_slow(s, flush)
}
#endif /* FASTEST */
#if 0
/* ===========================================================================
* For Z_RLE, simply look for runs of bytes, generate matches only of distance
* one. Do not maintain a hash table. (It will be regenerated if this run of
@@ -1751,11 +1742,9 @@ local block_state deflate_rle(s, flush)
deflate_state *s;
int flush;
{
int bflush; /* set if current block must be flushed */
uInt run; /* length of run */
uInt max; /* maximum length of run */
uInt prev; /* byte at distance one to match */
Bytef *scan; /* scan for end of run */
int bflush; /* set if current block must be flushed */
uInt prev; /* byte at distance one to match */
Bytef *scan, *strend; /* scan goes up to strend for length of run */
for (;;) {
/* Make sure that we always have enough lookahead, except
@@ -1771,23 +1760,33 @@ local block_state deflate_rle(s, flush)
}
/* See how many times the previous byte repeats */
run = 0;
if (s->strstart > 0) { /* if there is a previous byte, that is */
max = s->lookahead < MAX_MATCH ? s->lookahead : MAX_MATCH;
s->match_length = 0;
if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
scan = s->window + s->strstart - 1;
prev = *scan++;
do {
if (*scan++ != prev)
break;
} while (++run < max);
prev = *scan;
if (prev == *++scan && prev == *++scan && prev == *++scan) {
strend = s->window + s->strstart + MAX_MATCH;
do {
} while (prev == *++scan && prev == *++scan &&
prev == *++scan && prev == *++scan &&
prev == *++scan && prev == *++scan &&
prev == *++scan && prev == *++scan &&
scan < strend);
s->match_length = MAX_MATCH - (int)(strend - scan);
if (s->match_length > s->lookahead)
s->match_length = s->lookahead;
}
}
/* Emit match if have run of MIN_MATCH or longer, else emit literal */
if (run >= MIN_MATCH) {
check_match(s, s->strstart, s->strstart - 1, run);
_tr_tally_dist(s, 1, run - MIN_MATCH, bflush);
s->lookahead -= run;
s->strstart += run;
if (s->match_length >= MIN_MATCH) {
check_match(s, s->strstart, s->strstart - 1, s->match_length);
_tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
s->lookahead -= s->match_length;
s->strstart += s->match_length;
s->match_length = 0;
} else {
/* No match, output a literal byte */
Tracevv((stderr,"%c", s->window[s->strstart]));
@@ -1800,4 +1799,36 @@ local block_state deflate_rle(s, flush)
FLUSH_BLOCK(s, flush == Z_FINISH);
return flush == Z_FINISH ? finish_done : block_done;
}
#endif
/* ===========================================================================
* For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
* (It will be regenerated if this run of deflate switches away from Huffman.)
*/
local block_state deflate_huff(s, flush)
deflate_state *s;
int flush;
{
int bflush; /* set if current block must be flushed */
for (;;) {
/* Make sure that we have a literal to write. */
if (s->lookahead == 0) {
fill_window(s);
if (s->lookahead == 0) {
if (flush == Z_NO_FLUSH)
return need_more;
break; /* flush the current block */
}
}
/* Output a literal byte */
s->match_length = 0;
Tracevv((stderr,"%c", s->window[s->strstart]));
_tr_tally_lit (s, s->window[s->strstart], bflush);
s->lookahead--;
s->strstart++;
if (bflush) FLUSH_BLOCK(s, 0);
}
FLUSH_BLOCK(s, flush == Z_FINISH);
return flush == Z_FINISH ? finish_done : block_done;
}