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-rw-r--r--cpukit/zlib/deflate.c433
1 files changed, 266 insertions, 167 deletions
diff --git a/cpukit/zlib/deflate.c b/cpukit/zlib/deflate.c
index f70154e82d..fcd698cc62 100644
--- a/cpukit/zlib/deflate.c
+++ b/cpukit/zlib/deflate.c
@@ -1,5 +1,5 @@
/* deflate.c -- compress data using the deflation algorithm
- * Copyright (C) 1995-2005 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 Copyright 1995-2005 Jean-loup Gailly ";
+ " deflate 1.2.4 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,
@@ -110,11 +109,6 @@ local void check_match OF((deflate_state *s, IPos start, IPos match,
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
-#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
-/* Minimum amount of lookahead, except at the end of the input file.
- * See deflate.c for comments about the MIN_MATCH+1.
- */
-
/* Values for max_lazy_match, good_match and max_chain_length, depending on
* the desired pack level (0..9). The values given below have been tuned to
* exclude worst case performance for pathological files. Better values may be
@@ -201,11 +195,11 @@ struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
/* ========================================================================= */
-int ZEXPORT deflateInit_(
- z_streamp strm,
- int level,
- const char *version,
- int stream_size)
+int ZEXPORT deflateInit_(strm, level, version, stream_size)
+ z_streamp strm;
+ int level;
+ const char *version;
+ int stream_size;
{
return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
Z_DEFAULT_STRATEGY, version, stream_size);
@@ -213,15 +207,16 @@ int ZEXPORT deflateInit_(
}
/* ========================================================================= */
-int ZEXPORT deflateInit2_(
- z_streamp strm,
- int level,
- int method,
- int windowBits,
- int memLevel,
- int strategy,
- const char *version,
- int stream_size)
+int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
+ version, stream_size)
+ z_streamp strm;
+ int level;
+ int method;
+ int windowBits;
+ int memLevel;
+ int strategy;
+ const char *version;
+ int stream_size;
{
deflate_state *s;
int wrap = 1;
@@ -287,6 +282,8 @@ int ZEXPORT deflateInit2_(
s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
+ s->high_water = 0; /* nothing written to s->window yet */
+
s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
@@ -311,10 +308,10 @@ int ZEXPORT deflateInit2_(
}
/* ========================================================================= */
-int ZEXPORT deflateSetDictionary (
- z_streamp strm,
- const Bytef *dictionary,
- uInt dictLength)
+int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
+ z_streamp strm;
+ const Bytef *dictionary;
+ uInt dictLength;
{
deflate_state *s;
uInt length = dictLength;
@@ -331,8 +328,8 @@ int ZEXPORT deflateSetDictionary (
strm->adler = adler32(strm->adler, dictionary, dictLength);
if (length < MIN_MATCH) return Z_OK;
- if (length > MAX_DIST(s)) {
- length = MAX_DIST(s);
+ if (length > s->w_size) {
+ length = s->w_size;
dictionary += dictLength - length; /* use the tail of the dictionary */
}
zmemcpy(s->window, dictionary, length);
@@ -353,8 +350,8 @@ int ZEXPORT deflateSetDictionary (
}
/* ========================================================================= */
-int ZEXPORT deflateReset (
- z_streamp strm)
+int ZEXPORT deflateReset (strm)
+ z_streamp strm;
{
deflate_state *s;
@@ -389,9 +386,9 @@ int ZEXPORT deflateReset (
}
/* ========================================================================= */
-int ZEXPORT deflateSetHeader (
- z_streamp strm,
- gz_headerp head)
+int ZEXPORT deflateSetHeader (strm, head)
+ z_streamp strm;
+ gz_headerp head;
{
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
if (strm->state->wrap != 2) return Z_STREAM_ERROR;
@@ -400,10 +397,10 @@ int ZEXPORT deflateSetHeader (
}
/* ========================================================================= */
-int ZEXPORT deflatePrime (
- z_streamp strm,
- int bits,
- int value)
+int ZEXPORT deflatePrime (strm, bits, value)
+ z_streamp strm;
+ int bits;
+ int value;
{
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
strm->state->bi_valid = bits;
@@ -412,10 +409,10 @@ int ZEXPORT deflatePrime (
}
/* ========================================================================= */
-int ZEXPORT deflateParams(
- z_streamp strm,
- int level,
- int strategy)
+int ZEXPORT deflateParams(strm, level, strategy)
+ z_streamp strm;
+ int level;
+ int strategy;
{
deflate_state *s;
compress_func func;
@@ -434,9 +431,10 @@ int ZEXPORT deflateParams(
}
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;
@@ -450,12 +448,12 @@ int ZEXPORT deflateParams(
}
/* ========================================================================= */
-int ZEXPORT deflateTune(
- z_streamp strm,
- int good_length,
- int max_lazy,
- int nice_length,
- int max_chain)
+int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
+ z_streamp strm;
+ int good_length;
+ int max_lazy;
+ int nice_length;
+ int max_chain;
{
deflate_state *s;
@@ -480,33 +478,66 @@ int ZEXPORT deflateTune(
* resulting from using fixed blocks instead of stored blocks, which deflate
* can emit on compressed data for some combinations of the parameters.
*
- * This function could be more sophisticated to provide closer upper bounds
- * for every combination of windowBits and memLevel, as well as wrap.
- * But even the conservative upper bound of about 14% expansion does not
- * seem onerous for output buffer allocation.
+ * This function could be more sophisticated to provide closer upper bounds for
+ * every combination of windowBits and memLevel. But even the conservative
+ * upper bound of about 14% expansion does not seem onerous for output buffer
+ * allocation.
*/
-uLong ZEXPORT deflateBound(
- z_streamp strm,
- uLong sourceLen)
+uLong ZEXPORT deflateBound(strm, sourceLen)
+ z_streamp strm;
+ uLong sourceLen;
{
deflate_state *s;
- uLong destLen;
+ uLong complen, wraplen;
+ Bytef *str;
- /* conservative upper bound */
- destLen = sourceLen +
- ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
+ /* conservative upper bound for compressed data */
+ complen = sourceLen +
+ ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
- /* if can't get parameters, return conservative bound */
+ /* if can't get parameters, return conservative bound plus zlib wrapper */
if (strm == Z_NULL || strm->state == Z_NULL)
- return destLen;
+ return complen + 6;
- /* if not default parameters, return conservative bound */
+ /* compute wrapper length */
s = strm->state;
+ switch (s->wrap) {
+ case 0: /* raw deflate */
+ wraplen = 0;
+ break;
+ case 1: /* zlib wrapper */
+ wraplen = 6 + (s->strstart ? 4 : 0);
+ break;
+ case 2: /* gzip wrapper */
+ wraplen = 18;
+ if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
+ if (s->gzhead->extra != Z_NULL)
+ wraplen += 2 + s->gzhead->extra_len;
+ str = s->gzhead->name;
+ if (str != Z_NULL)
+ do {
+ wraplen++;
+ } while (*str++);
+ str = s->gzhead->comment;
+ if (str != Z_NULL)
+ do {
+ wraplen++;
+ } while (*str++);
+ if (s->gzhead->hcrc)
+ wraplen += 2;
+ }
+ break;
+ default: /* for compiler happiness */
+ wraplen = 6;
+ }
+
+ /* if not default parameters, return conservative bound */
if (s->w_bits != 15 || s->hash_bits != 8 + 7)
- return destLen;
+ return complen + wraplen;
/* default settings: return tight bound for that case */
- return compressBound(sourceLen);
+ return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
+ (sourceLen >> 25) + 13 - 6 + wraplen;
}
/* =========================================================================
@@ -514,9 +545,9 @@ uLong ZEXPORT deflateBound(
* IN assertion: the stream state is correct and there is enough room in
* pending_buf.
*/
-local void putShortMSB (
- deflate_state *s,
- uInt b)
+local void putShortMSB (s, b)
+ deflate_state *s;
+ uInt b;
{
put_byte(s, (Byte)(b >> 8));
put_byte(s, (Byte)(b & 0xff));
@@ -528,8 +559,8 @@ local void putShortMSB (
* to avoid allocating a large strm->next_out buffer and copying into it.
* (See also read_buf()).
*/
-local void flush_pending(
- z_streamp strm)
+local void flush_pending(strm)
+ z_streamp strm;
{
unsigned len = strm->state->pending;
@@ -548,15 +579,15 @@ local void flush_pending(
}
/* ========================================================================= */
-int ZEXPORT deflate (
- z_streamp strm,
- int flush)
+int ZEXPORT deflate (strm, flush)
+ z_streamp strm;
+ int flush;
{
int old_flush; /* value of flush param for previous deflate call */
deflate_state *s;
if (strm == Z_NULL || strm->state == Z_NULL ||
- flush > Z_FINISH || flush < 0) {
+ flush > Z_BLOCK || flush < 0) {
return Z_STREAM_ERROR;
}
s = strm->state;
@@ -580,7 +611,7 @@ int ZEXPORT deflate (
put_byte(s, 31);
put_byte(s, 139);
put_byte(s, 8);
- if (s->gzhead == NULL) {
+ if (s->gzhead == Z_NULL) {
put_byte(s, 0);
put_byte(s, 0);
put_byte(s, 0);
@@ -607,7 +638,7 @@ int ZEXPORT deflate (
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
4 : 0));
put_byte(s, s->gzhead->os & 0xff);
- if (s->gzhead->extra != NULL) {
+ if (s->gzhead->extra != Z_NULL) {
put_byte(s, s->gzhead->extra_len & 0xff);
put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
}
@@ -649,7 +680,7 @@ int ZEXPORT deflate (
}
#ifdef GZIP
if (s->status == EXTRA_STATE) {
- if (s->gzhead->extra != NULL) {
+ if (s->gzhead->extra != Z_NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
@@ -677,7 +708,7 @@ int ZEXPORT deflate (
s->status = NAME_STATE;
}
if (s->status == NAME_STATE) {
- if (s->gzhead->name != NULL) {
+ if (s->gzhead->name != Z_NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
int val;
@@ -708,7 +739,7 @@ int ZEXPORT deflate (
s->status = COMMENT_STATE;
}
if (s->status == COMMENT_STATE) {
- if (s->gzhead->comment != NULL) {
+ if (s->gzhead->comment != Z_NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
int val;
@@ -786,7 +817,9 @@ int ZEXPORT deflate (
(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;
@@ -807,13 +840,17 @@ int ZEXPORT deflate (
if (bstate == block_done) {
if (flush == Z_PARTIAL_FLUSH) {
_tr_align(s);
- } else { /* FULL_FLUSH or SYNC_FLUSH */
+ } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
_tr_stored_block(s, (char*)0, 0L, 0);
/* For a full flush, this empty block will be recognized
* as a special marker by inflate_sync().
*/
if (flush == Z_FULL_FLUSH) {
CLEAR_HASH(s); /* forget history */
+ if (s->lookahead == 0) {
+ s->strstart = 0;
+ s->block_start = 0L;
+ }
}
}
flush_pending(strm);
@@ -855,8 +892,8 @@ int ZEXPORT deflate (
}
/* ========================================================================= */
-int ZEXPORT deflateEnd (
- z_streamp strm)
+int ZEXPORT deflateEnd (strm)
+ z_streamp strm;
{
int status;
@@ -890,9 +927,9 @@ int ZEXPORT deflateEnd (
* To simplify the source, this is not supported for 16-bit MSDOS (which
* doesn't have enough memory anyway to duplicate compression states).
*/
-int ZEXPORT deflateCopy (
- z_streamp dest,
- z_streamp source)
+int ZEXPORT deflateCopy (dest, source)
+ z_streamp dest;
+ z_streamp source;
{
#ifdef MAXSEG_64K
return Z_STREAM_ERROR;
@@ -952,10 +989,10 @@ int ZEXPORT deflateCopy (
* allocating a large strm->next_in buffer and copying from it.
* (See also flush_pending()).
*/
-local int read_buf(
- z_streamp strm,
- Bytef *buf,
- unsigned size)
+local int read_buf(strm, buf, size)
+ z_streamp strm;
+ Bytef *buf;
+ unsigned size;
{
unsigned len = strm->avail_in;
@@ -982,8 +1019,8 @@ local int read_buf(
/* ===========================================================================
* Initialize the "longest match" routines for a new zlib stream
*/
-local void lm_init (
- deflate_state *s)
+local void lm_init (s)
+ deflate_state *s;
{
s->window_size = (ulg)2L*s->w_size;
@@ -1023,9 +1060,9 @@ local void lm_init (
/* For 80x86 and 680x0, an optimized version will be provided in match.asm or
* match.S. The code will be functionally equivalent.
*/
-local uInt longest_match(
- deflate_state *s,
- IPos cur_match) /* current match */
+local uInt longest_match(s, cur_match)
+ deflate_state *s;
+ IPos cur_match; /* current match */
{
unsigned chain_length = s->max_chain_length;/* max hash chain length */
register Bytef *scan = s->window + s->strstart; /* current string */
@@ -1166,14 +1203,15 @@ local uInt longest_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(
- deflate_state *s,
- IPos cur_match) /* current match */
+local uInt longest_match(s, cur_match)
+ deflate_state *s;
+ IPos cur_match; /* current match */
{
register Bytef *scan = s->window + s->strstart; /* current string */
register Bytef *match; /* matched string */
@@ -1224,14 +1262,16 @@ local uInt longest_match_fast(
return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
}
+#endif /* FASTEST */
+
#ifdef DEBUG
/* ===========================================================================
* Check that the match at match_start is indeed a match.
*/
-local void check_match(
- deflate_state *s,
- IPos start, IPos match,
- int length)
+local void check_match(s, start, match, length)
+ deflate_state *s;
+ IPos start, match;
+ int length;
{
/* check that the match is indeed a match */
if (zmemcmp(s->window + match,
@@ -1262,8 +1302,8 @@ local void check_match(
* performed for at least two bytes (required for the zip translate_eol
* option -- not supported here).
*/
-local void fill_window(
- deflate_state *s)
+local void fill_window(s)
+ deflate_state *s;
{
register unsigned n, m;
register Posf *p;
@@ -1302,7 +1342,6 @@ local void fill_window(
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 {
@@ -1354,27 +1393,61 @@ local void fill_window(
*/
} while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
+
+ /* If the WIN_INIT bytes after the end of the current data have never been
+ * written, then zero those bytes in order to avoid memory check reports of
+ * the use of uninitialized (or uninitialised as Julian writes) bytes by
+ * the longest match routines. Update the high water mark for the next
+ * time through here. WIN_INIT is set to MAX_MATCH since the longest match
+ * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
+ */
+ if (s->high_water < s->window_size) {
+ ulg curr = s->strstart + (ulg)(s->lookahead);
+ ulg init;
+
+ if (s->high_water < curr) {
+ /* Previous high water mark below current data -- zero WIN_INIT
+ * bytes or up to end of window, whichever is less.
+ */
+ init = s->window_size - curr;
+ if (init > WIN_INIT)
+ init = WIN_INIT;
+ zmemzero(s->window + curr, (unsigned)init);
+ s->high_water = curr + init;
+ }
+ else if (s->high_water < (ulg)curr + WIN_INIT) {
+ /* High water mark at or above current data, but below current data
+ * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
+ * to end of window, whichever is less.
+ */
+ init = (ulg)curr + WIN_INIT - s->high_water;
+ if (init > s->window_size - s->high_water)
+ init = s->window_size - s->high_water;
+ zmemzero(s->window + s->high_water, (unsigned)init);
+ s->high_water += init;
+ }
+ }
}
/* ===========================================================================
* Flush the current block, with given end-of-file flag.
* IN assertion: strstart is set to the end of the current match.
*/
-#define FLUSH_BLOCK_ONLY(s, eof) { \
+#define FLUSH_BLOCK_ONLY(s, last) { \
_tr_flush_block(s, (s->block_start >= 0L ? \
(charf *)&s->window[(unsigned)s->block_start] : \
(charf *)Z_NULL), \
(ulg)((long)s->strstart - s->block_start), \
- (eof)); \
+ (last)); \
s->block_start = s->strstart; \
flush_pending(s->strm); \
Tracev((stderr,"[FLUSH]")); \
}
/* Same but force premature exit if necessary. */
-#define FLUSH_BLOCK(s, eof) { \
- FLUSH_BLOCK_ONLY(s, eof); \
- if (s->strm->avail_out == 0) return (eof) ? finish_started : need_more; \
+#define FLUSH_BLOCK(s, last) { \
+ FLUSH_BLOCK_ONLY(s, last); \
+ if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
}
/* ===========================================================================
@@ -1386,9 +1459,9 @@ local void fill_window(
* NOTE: this function should be optimized to avoid extra copying from
* window to pending_buf.
*/
-local block_state deflate_stored(
- deflate_state *s,
- int flush)
+local block_state deflate_stored(s, flush)
+ deflate_state *s;
+ int flush;
{
/* Stored blocks are limited to 0xffff bytes, pending_buf is limited
* to pending_buf_size, and each stored block has a 5 byte header:
@@ -1444,11 +1517,11 @@ local block_state deflate_stored(
* new strings in the dictionary only for unmatched strings or for short
* matches. It is used only for the fast compression options.
*/
-local block_state deflate_fast(
- deflate_state *s,
- int flush)
+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 (;;) {
@@ -1468,6 +1541,7 @@ local block_state deflate_fast(
/* 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);
}
@@ -1480,19 +1554,8 @@ local block_state deflate_fast(
* 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);
@@ -1550,11 +1613,11 @@ local block_state deflate_fast(
* evaluation for matches: a match is finally adopted only if there is
* no better match at the next window position.
*/
-local block_state deflate_slow(
- deflate_state *s,
- int flush)
+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. */
@@ -1575,6 +1638,7 @@ local block_state deflate_slow(
/* 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);
}
@@ -1590,12 +1654,8 @@ local block_state deflate_slow(
* 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
@@ -1673,21 +1733,18 @@ local block_state deflate_slow(
}
#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
* deflate switches away from Z_RLE.)
*/
-local block_state deflate_rle(
- deflate_state *s,
- int flush)
+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
@@ -1703,23 +1760,33 @@ local block_state deflate_rle(
}
/* 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]));
@@ -1732,4 +1799,36 @@ local block_state deflate_rle(
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;
+}
generated by cgit v1.2.3 (git 2.25.1) at 2024-04-26 02:49:58 +0000