/* deflate.c -- compress data using the deflation algorithm
- * Copyright (C) 1992-1993 Jean-loup Gailly
- * This is free software; you can redistribute it and/or modify it under the
- * terms of the GNU General Public License, see the file COPYING.
- */
+
+ Copyright (C) 1999, 2006, 2009-2018 Free Software Foundation, Inc.
+ Copyright (C) 1992-1993 Jean-loup Gailly
+
+ This program 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 3, or (at your option)
+ any later version.
+
+ This program 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 this program; if not, write to the Free Software Foundation,
+ Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
/*
* PURPOSE
#include "tailor.h"
#include "gzip.h"
#include "lzw.h" /* just for consistency checking */
-
-#ifdef RCSID
-static char rcsid[] = "$Id: deflate.c,v 0.15 1993/06/24 10:53:53 jloup Exp $";
-#endif
+#include "verify.h"
/* ===========================================================================
* Configuration parameters
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
+#ifndef RSYNC_WIN
+# define RSYNC_WIN 4096
+#endif
+verify(RSYNC_WIN < MAX_DIST);
+
+#define RSYNC_SUM_MATCH(sum) ((sum) % RSYNC_WIN == 0)
+/* Whether window sum matches magic value */
+
/* ===========================================================================
* Local data used by the "longest match" routines.
*/
/* DECLARE(Pos, head, 1<<HASH_BITS); */
/* Heads of the hash chains or NIL. */
-ulg window_size = (ulg)2*WSIZE;
+static ulg window_size = (ulg)2*WSIZE;
/* window size, 2*WSIZE except for MMAP or BIG_MEM, where it is the
* input file length plus MIN_LOOKAHEAD.
*/
* H_SHIFT * MIN_MATCH >= HASH_BITS
*/
-unsigned int near prev_length;
+ unsigned int near prev_length;
/* Length of the best match at previous step. Matches not greater than this
* are discarded. This is used in the lazy match evaluation.
*/
local int eofile; /* flag set at end of input file */
local unsigned lookahead; /* number of valid bytes ahead in window */
-unsigned near max_chain_length;
+ unsigned max_chain_length;
/* To speed up deflation, hash chains are never searched beyond this length.
* A higher limit improves compression ratio but degrades the speed.
*/
local int compr_level;
/* compression level (1..9) */
-unsigned near good_match;
+unsigned good_match;
/* Use a faster search when the previous match is longer than this */
+local ulg rsync_sum; /* rolling sum of rsync window */
+local ulg rsync_chunk_end; /* next rsync sequence point */
/* 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
ush max_chain;
} config;
+#ifdef ASMV
+# define static_unless_ASMV
+#else
+# define static_unless_ASMV static
+#endif
+
#ifdef FULL_SEARCH
# define nice_match MAX_MATCH
#else
- int near nice_match; /* Stop searching when current match exceeds this */
+ /* Stop searching when current match exceeds this */
+ static_unless_ASMV int nice_match;
#endif
local config configuration_table[10] = {
* meaning.
*/
-#define EQUAL 0
-/* result of memcmp for equal strings */
-
/* ===========================================================================
* Prototypes for local functions.
*/
-local void fill_window OF((void));
-local off_t deflate_fast OF((void));
+local void fill_window (void);
+local off_t deflate_fast (void);
- int longest_match OF((IPos cur_match));
#ifdef ASMV
- void match_init OF((void)); /* asm code initialization */
+ int longest_match (IPos cur_match);
+ void match_init (void); /* asm code initialization */
#endif
#ifdef DEBUG
-local void check_match OF((IPos start, IPos match, int length));
+local void check_match (IPos start, IPos match, int length);
#endif
/* ===========================================================================
* Update a hash value with the given input byte
- * IN assertion: all calls to to UPDATE_HASH are made with consecutive
+ * IN assertion: all calls to UPDATE_HASH are made with consecutive
* input characters, so that a running hash key can be computed from the
* previous key instead of complete recalculation each time.
*/
* Insert string s in the dictionary and set match_head to the previous head
* of the hash chain (the most recent string with same hash key). Return
* the previous length of the hash chain.
- * IN assertion: all calls to to INSERT_STRING are made with consecutive
+ * IN assertion: all calls to INSERT_STRING are made with consecutive
* input characters and the first MIN_MATCH bytes of s are valid
* (except for the last MIN_MATCH-1 bytes of the input file).
*/
{
register unsigned j;
- if (pack_level < 1 || pack_level > 9) error("bad pack level");
+ if (pack_level < 1 || pack_level > 9) gzip_error ("bad pack level");
compr_level = pack_level;
/* Initialize the hash table. */
-#if defined(MAXSEG_64K) && HASH_BITS == 15
+#if defined MAXSEG_64K && HASH_BITS == 15
for (j = 0; j < HASH_SIZE; j++) head[j] = NIL;
#else
memzero((char*)head, HASH_SIZE*sizeof(*head));
#endif
/* prev will be initialized on the fly */
+ /* rsync params */
+ rsync_chunk_end = 0xFFFFFFFFUL;
+ rsync_sum = 0;
+
/* Set the default configuration parameters:
*/
max_lazy_match = configuration_table[pack_level].max_lazy;
#endif
lookahead = read_buf((char*)window,
- sizeof(int) <= 2 ? (unsigned)WSIZE : 2*WSIZE);
+ sizeof(int) <= 2 ? (unsigned)WSIZE : 2*WSIZE);
if (lookahead == 0 || lookahead == (unsigned)EOF) {
eofile = 1, lookahead = 0;
* match.s. The code is functionally equivalent, so you can use the C version
* if desired.
*/
-int longest_match(cur_match)
- IPos cur_match; /* current match */
+static int
+longest_match(IPos cur_match)
{
unsigned chain_length = max_chain_length; /* max hash chain length */
register uch *scan = window + strstart; /* current string */
/* Skip to next match if the match length cannot increase
* or if the match length is less than 2:
*/
-#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
+#if defined UNALIGNED_OK && MAX_MATCH == 258
/* This code assumes sizeof(unsigned short) == 2. Do not use
* UNALIGNED_OK if your compiler uses a different size.
*/
#endif
}
} while ((cur_match = prev[cur_match & WMASK]) > limit
- && --chain_length != 0);
+ && --chain_length != 0);
return best_len;
}
{
/* check that the match is indeed a match */
if (memcmp((char*)window + match,
- (char*)window + start, length) != EQUAL) {
+ (char*)window + start, length) != 0) {
fprintf(stderr,
" start %d, match %d, length %d\n",
start, match, length);
- error("invalid match");
+ gzip_error ("invalid match");
}
if (verbose > 1) {
fprintf(stderr,"\\[%d,%d]", start-match, length);
memcpy((char*)window, (char*)window+WSIZE, (unsigned)WSIZE);
match_start -= WSIZE;
strstart -= WSIZE; /* we now have strstart >= MAX_DIST: */
+ if (rsync_chunk_end != 0xFFFFFFFFUL)
+ rsync_chunk_end -= WSIZE;
block_start -= (long) WSIZE;
n = read_buf((char*)window+strstart+lookahead, more);
if (n == 0 || n == (unsigned)EOF) {
eofile = 1;
+ /* Don't let garbage pollute the dictionary. */
+ memzero (window + strstart + lookahead, MIN_MATCH - 1);
} else {
lookahead += n;
}
}
}
+/* With an initial offset of START, advance rsync's rolling checksum
+ by NUM bytes. */
+local void rsync_roll(unsigned int start, unsigned int num)
+{
+ unsigned i;
+
+ if (start < RSYNC_WIN) {
+ /* before window fills. */
+ for (i = start; i < RSYNC_WIN; i++) {
+ if (i == start + num)
+ return;
+ rsync_sum += (ulg)window[i];
+ }
+ num -= (RSYNC_WIN - start);
+ start = RSYNC_WIN;
+ }
+
+ /* buffer after window full */
+ for (i = start; i < start+num; i++) {
+ /* New character in */
+ rsync_sum += (ulg)window[i];
+ /* Old character out */
+ rsync_sum -= (ulg)window[i - RSYNC_WIN];
+ if (rsync_chunk_end == 0xFFFFFFFFUL && RSYNC_SUM_MATCH(rsync_sum))
+ rsync_chunk_end = i;
+ }
+}
+
+/* ===========================================================================
+ * Set rsync_chunk_end if window sum matches magic value.
+ */
+#define RSYNC_ROLL(s, n) \
+ do { if (rsync) rsync_roll((s), (n)); } while(0)
+
/* ===========================================================================
* 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(eof) \
flush_block(block_start >= 0L ? (char*)&window[(unsigned)block_start] : \
- (char*)NULL, (long)strstart - block_start, (eof))
+ (char*)NULL, (long)strstart - block_start, flush-1, (eof))
/* ===========================================================================
* Processes a new input file and return its compressed length. This
local off_t deflate_fast()
{
IPos hash_head; /* head of the hash chain */
- int flush; /* set if current block must be flushed */
+ int flush = 0; /* set if current block must be flushed, 2=>and padded */
unsigned match_length = 0; /* length of best match */
prev_length = MIN_MATCH-1;
/* Find the longest match, discarding those <= prev_length.
* At this point we have always match_length < MIN_MATCH
*/
- if (hash_head != NIL && strstart - hash_head <= MAX_DIST) {
+ if (hash_head != NIL && strstart - hash_head <= MAX_DIST
+ && strstart <= window_size - MIN_LOOKAHEAD) {
/* To simplify the code, we prevent matches with the string
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
lookahead -= match_length;
- /* Insert new strings in the hash table only if the match length
+ RSYNC_ROLL(strstart, match_length);
+ /* Insert new strings in the hash table only if the match length
* is not too large. This saves time but degrades compression.
*/
if (match_length <= max_insert_length) {
* the next lookahead bytes will be emitted as literals.
*/
} while (--match_length != 0);
- strstart++;
+ strstart++;
} else {
- strstart += match_length;
- match_length = 0;
- ins_h = window[strstart];
- UPDATE_HASH(ins_h, window[strstart+1]);
+ strstart += match_length;
+ match_length = 0;
+ ins_h = window[strstart];
+ UPDATE_HASH(ins_h, window[strstart+1]);
#if MIN_MATCH != 3
Call UPDATE_HASH() MIN_MATCH-3 more times
#endif
/* No match, output a literal byte */
Tracevv((stderr,"%c",window[strstart]));
flush = ct_tally (0, window[strstart]);
+ RSYNC_ROLL(strstart, 1);
lookahead--;
- strstart++;
+ strstart++;
+ }
+ if (rsync && strstart > rsync_chunk_end) {
+ rsync_chunk_end = 0xFFFFFFFFUL;
+ flush = 2;
}
if (flush) FLUSH_BLOCK(0), block_start = strstart;
{
IPos hash_head; /* head of hash chain */
IPos prev_match; /* previous match */
- int flush; /* set if current block must be flushed */
+ int flush = 0; /* set if current block must be flushed */
int match_available = 0; /* set if previous match exists */
register unsigned match_length = MIN_MATCH-1; /* length of best match */
match_length = MIN_MATCH-1;
if (hash_head != NIL && prev_length < max_lazy_match &&
- strstart - hash_head <= MAX_DIST) {
+ strstart - hash_head <= MAX_DIST &&
+ strstart <= window_size - MIN_LOOKAHEAD) {
/* To simplify the code, we prevent matches with the string
* of window index 0 (in particular we have to avoid a match
* of the string with itself at the start of the input file).
*/
lookahead -= prev_length-1;
prev_length -= 2;
+ RSYNC_ROLL(strstart, prev_length+1);
do {
strstart++;
INSERT_STRING(strstart, hash_head);
match_available = 0;
match_length = MIN_MATCH-1;
strstart++;
- if (flush) FLUSH_BLOCK(0), block_start = strstart;
+ if (rsync && strstart > rsync_chunk_end) {
+ rsync_chunk_end = 0xFFFFFFFFUL;
+ flush = 2;
+ }
+ if (flush) FLUSH_BLOCK(0), block_start = strstart;
} else if (match_available) {
/* If there was no match at the previous position, output a
* single literal. If there was a match but the current match
* is longer, truncate the previous match to a single literal.
*/
Tracevv((stderr,"%c",window[strstart-1]));
- if (ct_tally (0, window[strstart-1])) {
- FLUSH_BLOCK(0), block_start = strstart;
+ flush = ct_tally (0, window[strstart-1]);
+ if (rsync && strstart > rsync_chunk_end) {
+ rsync_chunk_end = 0xFFFFFFFFUL;
+ flush = 2;
}
+ if (flush) FLUSH_BLOCK(0), block_start = strstart;
+ RSYNC_ROLL(strstart, 1);
strstart++;
lookahead--;
} else {
/* There is no previous match to compare with, wait for
* the next step to decide.
*/
+ if (rsync && strstart > rsync_chunk_end) {
+ /* Reset huffman tree */
+ rsync_chunk_end = 0xFFFFFFFFUL;
+ flush = 2;
+ FLUSH_BLOCK(0), block_start = strstart;
+ }
+
match_available = 1;
+ RSYNC_ROLL(strstart, 1);
strstart++;
lookahead--;
}
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