X-Git-Url: https://git.gag.com/?a=blobdiff_plain;f=deflate.c;h=ecf02c3bf5643af35c943fb4684c521515662c5c;hb=3d2df61b0ca3aa4efd9258905402dc2a2c73c14c;hp=d81824826846421161374f88f887cb5963c7a240;hpb=95ace546d3f6c5909a636017f141784105f9dab2;p=debian%2Fgzip diff --git a/deflate.c b/deflate.c index d818248..ecf02c3 100644 --- a/deflate.c +++ b/deflate.c @@ -1,8 +1,21 @@ /* 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, 2009-2015 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 @@ -55,22 +68,19 @@ * void lm_init (int pack_level, ush *flags) * Initialize the "longest match" routines for a new file * - * ulg deflate (void) + * off_t deflate (void) * Processes a new input file and return its compressed length. Sets * the compressed length, crc, deflate flags and internal file * attributes. */ +#include #include #include "tailor.h" #include "gzip.h" #include "lzw.h" /* just for consistency checking */ -#ifdef RCSID -static char rcsid[] = "$Id$"; -#endif - /* =========================================================================== * Configuration parameters */ @@ -151,7 +161,7 @@ typedef unsigned IPos; /* DECLARE(Pos, head, 1<= 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. */ @@ -180,7 +190,7 @@ unsigned int near prev_length; 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. */ @@ -199,7 +209,7 @@ local unsigned int max_lazy_match; 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 */ @@ -216,10 +226,17 @@ typedef struct config { 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] = { @@ -241,27 +258,24 @@ 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 ulg 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. */ @@ -271,7 +285,7 @@ local void check_match OF((IPos start, IPos match, int length)); * 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). */ @@ -289,11 +303,11 @@ void lm_init (pack_level, flags) { 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)); @@ -322,7 +336,7 @@ void lm_init (pack_level, flags) #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; @@ -354,8 +368,8 @@ void lm_init (pack_level, flags) * 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 */ @@ -400,7 +414,7 @@ int longest_match(cur_match) /* 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. */ @@ -474,7 +488,7 @@ int longest_match(cur_match) #endif } } while ((cur_match = prev[cur_match & WMASK]) > limit - && --chain_length != 0); + && --chain_length != 0); return best_len; } @@ -490,11 +504,11 @@ local void check_match(start, match, length) { /* 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); @@ -557,6 +571,8 @@ local void fill_window() 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; } @@ -577,7 +593,7 @@ local void fill_window() * new strings in the dictionary only for unmatched strings or for short * matches. It is used only for the fast compression options. */ -local ulg deflate_fast() +local off_t deflate_fast() { IPos hash_head; /* head of the hash chain */ int flush; /* set if current block must be flushed */ @@ -593,7 +609,8 @@ local ulg deflate_fast() /* 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). @@ -609,7 +626,7 @@ local ulg deflate_fast() lookahead -= match_length; - /* Insert new strings in the hash table only if the 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) { @@ -623,12 +640,12 @@ local ulg deflate_fast() * 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 @@ -638,7 +655,7 @@ local ulg deflate_fast() Tracevv((stderr,"%c",window[strstart])); flush = ct_tally (0, window[strstart]); lookahead--; - strstart++; + strstart++; } if (flush) FLUSH_BLOCK(0), block_start = strstart; @@ -658,16 +675,13 @@ local ulg deflate_fast() * evaluation for matches: a match is finally adopted only if there is * no better match at the next window position. */ -ulg deflate() +off_t deflate() { IPos hash_head; /* head of hash chain */ IPos prev_match; /* previous match */ int flush; /* 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 */ -#ifdef DEBUG - extern long isize; /* byte length of input file, for debug only */ -#endif if (compr_level <= 3) return deflate_fast(); /* optimized for speed */ @@ -684,7 +698,8 @@ ulg deflate() 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). @@ -748,7 +763,7 @@ ulg deflate() strstart++; lookahead--; } - Assert (strstart <= isize && lookahead <= isize, "a bit too far"); + Assert (strstart <= bytes_in && lookahead <= bytes_in, "a bit too far"); /* Make sure that we always have enough lookahead, except * at the end of the input file. We need MAX_MATCH bytes