diff options
Diffstat (limited to 'lib/zlib/src/deflate.c')
| -rw-r--r-- | lib/zlib/src/deflate.c | 2700 |
1 files changed, 1350 insertions, 1350 deletions
diff --git a/lib/zlib/src/deflate.c b/lib/zlib/src/deflate.c index a891418..7f60791 100644 --- a/lib/zlib/src/deflate.c +++ b/lib/zlib/src/deflate.c @@ -1,1350 +1,1350 @@ -/* deflate.c -- compress data using the deflation algorithm
- * Copyright (C) 1995-2002 Jean-loup Gailly.
- * For conditions of distribution and use, see copyright notice in zlib.h
- */
-
-/*
- * ALGORITHM
- *
- * The "deflation" process depends on being able to identify portions
- * of the input text which are identical to earlier input (within a
- * sliding window trailing behind the input currently being processed).
- *
- * The most straightforward technique turns out to be the fastest for
- * most input files: try all possible matches and select the longest.
- * The key feature of this algorithm is that insertions into the string
- * dictionary are very simple and thus fast, and deletions are avoided
- * completely. Insertions are performed at each input character, whereas
- * string matches are performed only when the previous match ends. So it
- * is preferable to spend more time in matches to allow very fast string
- * insertions and avoid deletions. The matching algorithm for small
- * strings is inspired from that of Rabin & Karp. A brute force approach
- * is used to find longer strings when a small match has been found.
- * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
- * (by Leonid Broukhis).
- * A previous version of this file used a more sophisticated algorithm
- * (by Fiala and Greene) which is guaranteed to run in linear amortized
- * time, but has a larger average cost, uses more memory and is patented.
- * However the F&G algorithm may be faster for some highly redundant
- * files if the parameter max_chain_length (described below) is too large.
- *
- * ACKNOWLEDGEMENTS
- *
- * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
- * I found it in 'freeze' written by Leonid Broukhis.
- * Thanks to many people for bug reports and testing.
- *
- * REFERENCES
- *
- * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
- * Available in ftp://ds.internic.net/rfc/rfc1951.txt
- *
- * A description of the Rabin and Karp algorithm is given in the book
- * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
- *
- * Fiala,E.R., and Greene,D.H.
- * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
- *
- */
-
-/* @(#) $Id: deflate.c,v 1.2 2004-11-27 21:35:22 pixel Exp $ */
-
-#include "deflate.h"
-
-const char deflate_copyright[] =
- " deflate 1.1.4 Copyright 1995-2002 Jean-loup Gailly ";
-/*
- 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
- include such an acknowledgment, I would appreciate that you keep this
- copyright string in the executable of your product.
- */
-
-/* ===========================================================================
- * Function prototypes.
- */
-typedef enum {
- need_more, /* block not completed, need more input or more output */
- block_done, /* block flush performed */
- finish_started, /* finish started, need only more output at next deflate */
- finish_done /* finish done, accept no more input or output */
-} block_state;
-
-typedef block_state (*compress_func) OF((deflate_state *s, int flush));
-/* Compression function. Returns the block state after the call. */
-
-local void fill_window OF((deflate_state *s));
-local block_state deflate_stored OF((deflate_state *s, int flush));
-local block_state deflate_fast OF((deflate_state *s, int flush));
-local block_state deflate_slow 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));
-#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
-
-#ifdef DEBUG
-local void check_match OF((deflate_state *s, IPos start, IPos match,
- int length));
-#endif
-
-/* ===========================================================================
- * Local data
- */
-
-#define NIL 0
-/* Tail of hash chains */
-
-#ifndef TOO_FAR
-# define TOO_FAR 4096
-#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
- * found for specific files.
- */
-typedef struct config_s {
- ush good_length; /* reduce lazy search above this match length */
- ush max_lazy; /* do not perform lazy search above this match length */
- ush nice_length; /* quit search above this match length */
- ush max_chain;
- compress_func func;
-} config;
-
-local const config configuration_table[10] = {
-/* good lazy nice chain */
-/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
-/* 1 */ {4, 4, 8, 4, deflate_fast}, /* maximum speed, no lazy matches */
-/* 2 */ {4, 5, 16, 8, deflate_fast},
-/* 3 */ {4, 6, 32, 32, deflate_fast},
-
-/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
-/* 5 */ {8, 16, 32, 32, deflate_slow},
-/* 6 */ {8, 16, 128, 128, deflate_slow},
-/* 7 */ {8, 32, 128, 256, deflate_slow},
-/* 8 */ {32, 128, 258, 1024, deflate_slow},
-/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* maximum compression */
-
-/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
- * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
- * meaning.
- */
-
-#define EQUAL 0
-/* result of memcmp for equal strings */
-
-struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
-
-/* ===========================================================================
- * Update a hash value with the given input byte
- * IN assertion: all calls to 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.
- */
-#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
-
-
-/* ===========================================================================
- * Insert string str 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.
- * If this file is compiled with -DFASTEST, the compression level is forced
- * to 1, and no hash chains are maintained.
- * IN assertion: all calls to to INSERT_STRING are made with consecutive
- * input characters and the first MIN_MATCH bytes of str are valid
- * (except for the last MIN_MATCH-1 bytes of the input file).
- */
-#ifdef FASTEST
-#define INSERT_STRING(s, str, match_head) \
- (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
- match_head = s->head[s->ins_h], \
- s->head[s->ins_h] = (Pos)(str))
-#else
-#define INSERT_STRING(s, str, match_head) \
- (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
- s->prev[(str) & s->w_mask] = match_head = s->head[s->ins_h], \
- s->head[s->ins_h] = (Pos)(str))
-#endif
-
-/* ===========================================================================
- * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
- * prev[] will be initialized on the fly.
- */
-#define CLEAR_HASH(s) \
- s->head[s->hash_size-1] = NIL; \
- zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
-
-/* ========================================================================= */
-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);
- /* To do: ignore strm->next_in if we use it as window */
-}
-
-/* ========================================================================= */
-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 noheader = 0;
- static const char* my_version = ZLIB_VERSION;
-
- ushf *overlay;
- /* We overlay pending_buf and d_buf+l_buf. This works since the average
- * output size for (length,distance) codes is <= 24 bits.
- */
-
- if (version == Z_NULL || version[0] != my_version[0] ||
- stream_size != sizeof(z_stream)) {
- return Z_VERSION_ERROR;
- }
- if (strm == Z_NULL) return Z_STREAM_ERROR;
-
- strm->msg = Z_NULL;
- if (strm->zalloc == Z_NULL) {
- strm->zalloc = zcalloc;
- strm->opaque = (voidpf)0;
- }
- if (strm->zfree == Z_NULL) strm->zfree = zcfree;
-
- if (level == Z_DEFAULT_COMPRESSION) level = 6;
-#ifdef FASTEST
- level = 1;
-#endif
-
- if (windowBits < 0) { /* undocumented feature: suppress zlib header */
- noheader = 1;
- windowBits = -windowBits;
- }
- if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
- windowBits < 9 || windowBits > 15 || level < 0 || level > 9 ||
- strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
- return Z_STREAM_ERROR;
- }
- s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
- if (s == Z_NULL) return Z_MEM_ERROR;
- strm->state = (struct internal_state FAR *)s;
- s->strm = strm;
-
- s->noheader = noheader;
- s->w_bits = windowBits;
- s->w_size = 1 << s->w_bits;
- s->w_mask = s->w_size - 1;
-
- s->hash_bits = memLevel + 7;
- s->hash_size = 1 << s->hash_bits;
- s->hash_mask = s->hash_size - 1;
- s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
-
- s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
- s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
- s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
-
- s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
-
- overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
- s->pending_buf = (uchf *) overlay;
- s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
-
- if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
- s->pending_buf == Z_NULL) {
- strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
- deflateEnd (strm);
- return Z_MEM_ERROR;
- }
- s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
- s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
-
- s->level = level;
- s->strategy = strategy;
- s->method = (Byte)method;
-
- return deflateReset(strm);
-}
-
-/* ========================================================================= */
-int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
- z_streamp strm;
- const Bytef *dictionary;
- uInt dictLength;
-{
- deflate_state *s;
- uInt length = dictLength;
- uInt n;
- IPos hash_head = 0;
-
- if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
- strm->state->status != INIT_STATE) return Z_STREAM_ERROR;
-
- s = strm->state;
- strm->adler = adler32(strm->adler, dictionary, dictLength);
-
- if (length < MIN_MATCH) return Z_OK;
- if (length > MAX_DIST(s)) {
- length = MAX_DIST(s);
-#ifndef USE_DICT_HEAD
- dictionary += dictLength - length; /* use the tail of the dictionary */
-#endif
- }
- zmemcpy(s->window, dictionary, length);
- s->strstart = length;
- s->block_start = (long)length;
-
- /* Insert all strings in the hash table (except for the last two bytes).
- * s->lookahead stays null, so s->ins_h will be recomputed at the next
- * call of fill_window.
- */
- s->ins_h = s->window[0];
- UPDATE_HASH(s, s->ins_h, s->window[1]);
- for (n = 0; n <= length - MIN_MATCH; n++) {
- INSERT_STRING(s, n, hash_head);
- }
- if (hash_head) hash_head = 0; /* to make compiler happy */
- return Z_OK;
-}
-
-/* ========================================================================= */
-int ZEXPORT deflateReset (strm)
- z_streamp strm;
-{
- deflate_state *s;
-
- if (strm == Z_NULL || strm->state == Z_NULL ||
- strm->zalloc == Z_NULL || strm->zfree == Z_NULL) return Z_STREAM_ERROR;
-
- strm->total_in = strm->total_out = 0;
- strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
- strm->data_type = Z_UNKNOWN;
-
- s = (deflate_state *)strm->state;
- s->pending = 0;
- s->pending_out = s->pending_buf;
-
- if (s->noheader < 0) {
- s->noheader = 0; /* was set to -1 by deflate(..., Z_FINISH); */
- }
- s->status = s->noheader ? BUSY_STATE : INIT_STATE;
- strm->adler = 1;
- s->last_flush = Z_NO_FLUSH;
-
- _tr_init(s);
- lm_init(s);
-
- return Z_OK;
-}
-
-/* ========================================================================= */
-int ZEXPORT deflateParams(strm, level, strategy)
- z_streamp strm;
- int level;
- int strategy;
-{
- deflate_state *s;
- compress_func func;
- int err = Z_OK;
-
- if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
- s = strm->state;
-
- if (level == Z_DEFAULT_COMPRESSION) {
- level = 6;
- }
- if (level < 0 || level > 9 || strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
- return Z_STREAM_ERROR;
- }
- func = configuration_table[s->level].func;
-
- if (func != configuration_table[level].func && strm->total_in != 0) {
- /* Flush the last buffer: */
- err = deflate(strm, Z_PARTIAL_FLUSH);
- }
- if (s->level != level) {
- s->level = level;
- s->max_lazy_match = configuration_table[level].max_lazy;
- s->good_match = configuration_table[level].good_length;
- s->nice_match = configuration_table[level].nice_length;
- s->max_chain_length = configuration_table[level].max_chain;
- }
- s->strategy = strategy;
- return err;
-}
-
-/* =========================================================================
- * Put a short in the pending buffer. The 16-bit value is put in MSB order.
- * IN assertion: the stream state is correct and there is enough room in
- * pending_buf.
- */
-local void putShortMSB (s, b)
- deflate_state *s;
- uInt b;
-{
- put_byte(s, (Byte)(b >> 8));
- put_byte(s, (Byte)(b & 0xff));
-}
-
-/* =========================================================================
- * Flush as much pending output as possible. All deflate() output goes
- * through this function so some applications may wish to modify it
- * to avoid allocating a large strm->next_out buffer and copying into it.
- * (See also read_buf()).
- */
-local void flush_pending(strm)
- z_streamp strm;
-{
- unsigned len = strm->state->pending;
-
- if (len > strm->avail_out) len = strm->avail_out;
- if (len == 0) return;
-
- zmemcpy(strm->next_out, strm->state->pending_out, len);
- strm->next_out += len;
- strm->state->pending_out += len;
- strm->total_out += len;
- strm->avail_out -= len;
- strm->state->pending -= len;
- if (strm->state->pending == 0) {
- strm->state->pending_out = strm->state->pending_buf;
- }
-}
-
-/* ========================================================================= */
-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) {
- return Z_STREAM_ERROR;
- }
- s = strm->state;
-
- if (strm->next_out == Z_NULL ||
- (strm->next_in == Z_NULL && strm->avail_in != 0) ||
- (s->status == FINISH_STATE && flush != Z_FINISH)) {
- ERR_RETURN(strm, Z_STREAM_ERROR);
- }
- if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
-
- s->strm = strm; /* just in case */
- old_flush = s->last_flush;
- s->last_flush = flush;
-
- /* Write the zlib header */
- if (s->status == INIT_STATE) {
-
- uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
- uInt level_flags = (s->level-1) >> 1;
-
- if (level_flags > 3) level_flags = 3;
- header |= (level_flags << 6);
- if (s->strstart != 0) header |= PRESET_DICT;
- header += 31 - (header % 31);
-
- s->status = BUSY_STATE;
- putShortMSB(s, header);
-
- /* Save the adler32 of the preset dictionary: */
- if (s->strstart != 0) {
- putShortMSB(s, (uInt)(strm->adler >> 16));
- putShortMSB(s, (uInt)(strm->adler & 0xffff));
- }
- strm->adler = 1L;
- }
-
- /* Flush as much pending output as possible */
- if (s->pending != 0) {
- flush_pending(strm);
- if (strm->avail_out == 0) {
- /* Since avail_out is 0, deflate will be called again with
- * more output space, but possibly with both pending and
- * avail_in equal to zero. There won't be anything to do,
- * but this is not an error situation so make sure we
- * return OK instead of BUF_ERROR at next call of deflate:
- */
- s->last_flush = -1;
- return Z_OK;
- }
-
- /* Make sure there is something to do and avoid duplicate consecutive
- * flushes. For repeated and useless calls with Z_FINISH, we keep
- * returning Z_STREAM_END instead of Z_BUFF_ERROR.
- */
- } else if (strm->avail_in == 0 && flush <= old_flush &&
- flush != Z_FINISH) {
- ERR_RETURN(strm, Z_BUF_ERROR);
- }
-
- /* User must not provide more input after the first FINISH: */
- if (s->status == FINISH_STATE && strm->avail_in != 0) {
- ERR_RETURN(strm, Z_BUF_ERROR);
- }
-
- /* Start a new block or continue the current one.
- */
- if (strm->avail_in != 0 || s->lookahead != 0 ||
- (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
- block_state bstate;
-
- bstate = (*(configuration_table[s->level].func))(s, flush);
-
- if (bstate == finish_started || bstate == finish_done) {
- s->status = FINISH_STATE;
- }
- if (bstate == need_more || bstate == finish_started) {
- if (strm->avail_out == 0) {
- s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
- }
- return Z_OK;
- /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
- * of deflate should use the same flush parameter to make sure
- * that the flush is complete. So we don't have to output an
- * empty block here, this will be done at next call. This also
- * ensures that for a very small output buffer, we emit at most
- * one empty block.
- */
- }
- if (bstate == block_done) {
- if (flush == Z_PARTIAL_FLUSH) {
- _tr_align(s);
- } else { /* 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 */
- }
- }
- flush_pending(strm);
- if (strm->avail_out == 0) {
- s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
- return Z_OK;
- }
- }
- }
- Assert(strm->avail_out > 0, "bug2");
-
- if (flush != Z_FINISH) return Z_OK;
- if (s->noheader) return Z_STREAM_END;
-
- /* Write the zlib trailer (adler32) */
- putShortMSB(s, (uInt)(strm->adler >> 16));
- putShortMSB(s, (uInt)(strm->adler & 0xffff));
- flush_pending(strm);
- /* If avail_out is zero, the application will call deflate again
- * to flush the rest.
- */
- s->noheader = -1; /* write the trailer only once! */
- return s->pending != 0 ? Z_OK : Z_STREAM_END;
-}
-
-/* ========================================================================= */
-int ZEXPORT deflateEnd (strm)
- z_streamp strm;
-{
- int status;
-
- if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
-
- status = strm->state->status;
- if (status != INIT_STATE && status != BUSY_STATE &&
- status != FINISH_STATE) {
- return Z_STREAM_ERROR;
- }
-
- /* Deallocate in reverse order of allocations: */
- TRY_FREE(strm, strm->state->pending_buf);
- TRY_FREE(strm, strm->state->head);
- TRY_FREE(strm, strm->state->prev);
- TRY_FREE(strm, strm->state->window);
-
- ZFREE(strm, strm->state);
- strm->state = Z_NULL;
-
- return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
-}
-
-/* =========================================================================
- * Copy the source state to the destination state.
- * 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 (dest, source)
- z_streamp dest;
- z_streamp source;
-{
-#ifdef MAXSEG_64K
- return Z_STREAM_ERROR;
-#else
- deflate_state *ds;
- deflate_state *ss;
- ushf *overlay;
-
-
- if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
- return Z_STREAM_ERROR;
- }
-
- ss = source->state;
-
- *dest = *source;
-
- ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
- if (ds == Z_NULL) return Z_MEM_ERROR;
- dest->state = (struct internal_state FAR *) ds;
- *ds = *ss;
- ds->strm = dest;
-
- ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
- ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
- ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
- overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
- ds->pending_buf = (uchf *) overlay;
-
- if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
- ds->pending_buf == Z_NULL) {
- deflateEnd (dest);
- return Z_MEM_ERROR;
- }
- /* following zmemcpy do not work for 16-bit MSDOS */
- zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
- zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
- zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
- zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
-
- ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
- ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
- ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
-
- ds->l_desc.dyn_tree = ds->dyn_ltree;
- ds->d_desc.dyn_tree = ds->dyn_dtree;
- ds->bl_desc.dyn_tree = ds->bl_tree;
-
- return Z_OK;
-#endif
-}
-
-/* ===========================================================================
- * Read a new buffer from the current input stream, update the adler32
- * and total number of bytes read. All deflate() input goes through
- * this function so some applications may wish to modify it to avoid
- * allocating a large strm->next_in buffer and copying from it.
- * (See also flush_pending()).
- */
-local int read_buf(strm, buf, size)
- z_streamp strm;
- Bytef *buf;
- unsigned size;
-{
- unsigned len = strm->avail_in;
-
- if (len > size) len = size;
- if (len == 0) return 0;
-
- strm->avail_in -= len;
-
- if (!strm->state->noheader) {
- strm->adler = adler32(strm->adler, strm->next_in, len);
- }
- zmemcpy(buf, strm->next_in, len);
- strm->next_in += len;
- strm->total_in += len;
-
- return (int)len;
-}
-
-/* ===========================================================================
- * Initialize the "longest match" routines for a new zlib stream
- */
-local void lm_init (s)
- deflate_state *s;
-{
- s->window_size = (ulg)2L*s->w_size;
-
- CLEAR_HASH(s);
-
- /* Set the default configuration parameters:
- */
- s->max_lazy_match = configuration_table[s->level].max_lazy;
- s->good_match = configuration_table[s->level].good_length;
- s->nice_match = configuration_table[s->level].nice_length;
- s->max_chain_length = configuration_table[s->level].max_chain;
-
- s->strstart = 0;
- s->block_start = 0L;
- s->lookahead = 0;
- s->match_length = s->prev_length = MIN_MATCH-1;
- s->match_available = 0;
- s->ins_h = 0;
-#ifdef ASMV
- match_init(); /* initialize the asm code */
-#endif
-}
-
-/* ===========================================================================
- * Set match_start to the longest match starting at the given string and
- * return its length. Matches shorter or equal to prev_length are discarded,
- * in which case the result is equal to prev_length and match_start is
- * garbage.
- * IN assertions: cur_match is the head of the hash chain for the current
- * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
- * OUT assertion: the match length is not greater than s->lookahead.
- */
-#ifndef ASMV
-/* For 80x86 and 680x0, an optimized version will be provided in match.asm or
- * match.S. The code will be functionally equivalent.
- */
-#ifndef FASTEST
-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 */
- register Bytef *match; /* matched string */
- register int len; /* length of current match */
- int best_len = s->prev_length; /* best match length so far */
- int nice_match = s->nice_match; /* stop if match long enough */
- IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
- s->strstart - (IPos)MAX_DIST(s) : NIL;
- /* Stop when cur_match becomes <= limit. To simplify the code,
- * we prevent matches with the string of window index 0.
- */
- Posf *prev = s->prev;
- uInt wmask = s->w_mask;
-
-#ifdef UNALIGNED_OK
- /* Compare two bytes at a time. Note: this is not always beneficial.
- * Try with and without -DUNALIGNED_OK to check.
- */
- register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
- register ush scan_start = *(ushf*)scan;
- register ush scan_end = *(ushf*)(scan+best_len-1);
-#else
- register Bytef *strend = s->window + s->strstart + MAX_MATCH;
- register Byte scan_end1 = scan[best_len-1];
- register Byte scan_end = scan[best_len];
-#endif
-
- /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
- * It is easy to get rid of this optimization if necessary.
- */
- Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
-
- /* Do not waste too much time if we already have a good match: */
- if (s->prev_length >= s->good_match) {
- chain_length >>= 2;
- }
- /* Do not look for matches beyond the end of the input. This is necessary
- * to make deflate deterministic.
- */
- if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
-
- Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
-
- do {
- Assert(cur_match < s->strstart, "no future");
- match = s->window + 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)
- /* This code assumes sizeof(unsigned short) == 2. Do not use
- * UNALIGNED_OK if your compiler uses a different size.
- */
- if (*(ushf*)(match+best_len-1) != scan_end ||
- *(ushf*)match != scan_start) continue;
-
- /* It is not necessary to compare scan[2] and match[2] since they are
- * always equal when the other bytes match, given that the hash keys
- * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
- * strstart+3, +5, ... up to strstart+257. We check for insufficient
- * lookahead only every 4th comparison; the 128th check will be made
- * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
- * necessary to put more guard bytes at the end of the window, or
- * to check more often for insufficient lookahead.
- */
- Assert(scan[2] == match[2], "scan[2]?");
- scan++, match++;
- do {
- } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
- *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
- *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
- *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
- scan < strend);
- /* The funny "do {}" generates better code on most compilers */
-
- /* Here, scan <= window+strstart+257 */
- Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
- if (*scan == *match) scan++;
-
- len = (MAX_MATCH - 1) - (int)(strend-scan);
- scan = strend - (MAX_MATCH-1);
-
-#else /* UNALIGNED_OK */
-
- if (match[best_len] != scan_end ||
- match[best_len-1] != scan_end1 ||
- *match != *scan ||
- *++match != scan[1]) continue;
-
- /* The check at best_len-1 can be removed because it will be made
- * again later. (This heuristic is not always a win.)
- * It is not necessary to compare scan[2] and match[2] since they
- * are always equal when the other bytes match, given that
- * the hash keys are equal and that HASH_BITS >= 8.
- */
- scan += 2, match++;
- Assert(*scan == *match, "match[2]?");
-
- /* We check for insufficient lookahead only every 8th comparison;
- * the 256th check will be made at strstart+258.
- */
- do {
- } while (*++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- scan < strend);
-
- Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
-
- len = MAX_MATCH - (int)(strend - scan);
- scan = strend - MAX_MATCH;
-
-#endif /* UNALIGNED_OK */
-
- if (len > best_len) {
- s->match_start = cur_match;
- best_len = len;
- if (len >= nice_match) break;
-#ifdef UNALIGNED_OK
- scan_end = *(ushf*)(scan+best_len-1);
-#else
- scan_end1 = scan[best_len-1];
- scan_end = scan[best_len];
-#endif
- }
- } while ((cur_match = prev[cur_match & wmask]) > limit
- && --chain_length != 0);
-
- if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
- return s->lookahead;
-}
-
-#else /* FASTEST */
-/* ---------------------------------------------------------------------------
- * Optimized version for level == 1 only
- */
-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 */
- register int len; /* length of current match */
- register Bytef *strend = s->window + s->strstart + MAX_MATCH;
-
- /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
- * It is easy to get rid of this optimization if necessary.
- */
- Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
-
- Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
-
- Assert(cur_match < s->strstart, "no future");
-
- match = s->window + cur_match;
-
- /* Return failure if the match length is less than 2:
- */
- if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
-
- /* The check at best_len-1 can be removed because it will be made
- * again later. (This heuristic is not always a win.)
- * It is not necessary to compare scan[2] and match[2] since they
- * are always equal when the other bytes match, given that
- * the hash keys are equal and that HASH_BITS >= 8.
- */
- scan += 2, match += 2;
- Assert(*scan == *match, "match[2]?");
-
- /* We check for insufficient lookahead only every 8th comparison;
- * the 256th check will be made at strstart+258.
- */
- do {
- } while (*++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- scan < strend);
-
- Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
-
- len = MAX_MATCH - (int)(strend - scan);
-
- if (len < MIN_MATCH) return MIN_MATCH - 1;
-
- s->match_start = cur_match;
- return len <= s->lookahead ? len : s->lookahead;
-}
-#endif /* FASTEST */
-#endif /* ASMV */
-
-#ifdef DEBUG
-/* ===========================================================================
- * Check that the match at match_start is indeed a match.
- */
-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,
- s->window + start, length) != EQUAL) {
- fprintf(stderr, " start %u, match %u, length %d\n",
- start, match, length);
- do {
- fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
- } while (--length != 0);
- z_error("invalid match");
- }
- if (z_verbose > 1) {
- fprintf(stderr,"\\[%d,%d]", start-match, length);
- do { putc(s->window[start++], stderr); } while (--length != 0);
- }
-}
-#else
-# define check_match(s, start, match, length)
-#endif
-
-/* ===========================================================================
- * Fill the window when the lookahead becomes insufficient.
- * Updates strstart and lookahead.
- *
- * IN assertion: lookahead < MIN_LOOKAHEAD
- * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
- * At least one byte has been read, or avail_in == 0; reads are
- * performed for at least two bytes (required for the zip translate_eol
- * option -- not supported here).
- */
-local void fill_window(s)
- deflate_state *s;
-{
- register unsigned n, m;
- register Posf *p;
- unsigned more; /* Amount of free space at the end of the window. */
- uInt wsize = s->w_size;
-
- do {
- more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
-
- /* Deal with !@#$% 64K limit: */
- if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
- more = wsize;
-
- } else if (more == (unsigned)(-1)) {
- /* Very unlikely, but possible on 16 bit machine if strstart == 0
- * and lookahead == 1 (input done one byte at time)
- */
- more--;
-
- /* If the window is almost full and there is insufficient lookahead,
- * move the upper half to the lower one to make room in the upper half.
- */
- } else if (s->strstart >= wsize+MAX_DIST(s)) {
-
- zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
- s->match_start -= wsize;
- s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
- s->block_start -= (long) wsize;
-
- /* Slide the hash table (could be avoided with 32 bit values
- at the expense of memory usage). We slide even when level == 0
- to keep the hash table consistent if we switch back to level > 0
- later. (Using level 0 permanently is not an optimal usage of
- zlib, so we don't care about this pathological case.)
- */
- n = s->hash_size;
- p = &s->head[n];
- do {
- m = *--p;
- *p = (Pos)(m >= wsize ? m-wsize : NIL);
- } while (--n);
-
- n = wsize;
-#ifndef FASTEST
- p = &s->prev[n];
- do {
- m = *--p;
- *p = (Pos)(m >= wsize ? m-wsize : NIL);
- /* If n is not on any hash chain, prev[n] is garbage but
- * its value will never be used.
- */
- } while (--n);
-#endif
- more += wsize;
- }
- if (s->strm->avail_in == 0) return;
-
- /* If there was no sliding:
- * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
- * more == window_size - lookahead - strstart
- * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
- * => more >= window_size - 2*WSIZE + 2
- * In the BIG_MEM or MMAP case (not yet supported),
- * window_size == input_size + MIN_LOOKAHEAD &&
- * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
- * Otherwise, window_size == 2*WSIZE so more >= 2.
- * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
- */
- Assert(more >= 2, "more < 2");
-
- n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
- s->lookahead += n;
-
- /* Initialize the hash value now that we have some input: */
- if (s->lookahead >= MIN_MATCH) {
- s->ins_h = s->window[s->strstart];
- UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
-#if MIN_MATCH != 3
- Call UPDATE_HASH() MIN_MATCH-3 more times
-#endif
- }
- /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
- * but this is not important since only literal bytes will be emitted.
- */
-
- } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 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_ONLY(s, eof) { \
- _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)); \
- 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; \
-}
-
-/* ===========================================================================
- * Copy without compression as much as possible from the input stream, return
- * the current block state.
- * This function does not insert new strings in the dictionary since
- * uncompressible data is probably not useful. This function is used
- * only for the level=0 compression option.
- * NOTE: this function should be optimized to avoid extra copying from
- * window to pending_buf.
- */
-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:
- */
- ulg max_block_size = 0xffff;
- ulg max_start;
-
- if (max_block_size > s->pending_buf_size - 5) {
- max_block_size = s->pending_buf_size - 5;
- }
-
- /* Copy as much as possible from input to output: */
- for (;;) {
- /* Fill the window as much as possible: */
- if (s->lookahead <= 1) {
-
- Assert(s->strstart < s->w_size+MAX_DIST(s) ||
- s->block_start >= (long)s->w_size, "slide too late");
-
- fill_window(s);
- if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
-
- if (s->lookahead == 0) break; /* flush the current block */
- }
- Assert(s->block_start >= 0L, "block gone");
-
- s->strstart += s->lookahead;
- s->lookahead = 0;
-
- /* Emit a stored block if pending_buf will be full: */
- max_start = s->block_start + max_block_size;
- if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
- /* strstart == 0 is possible when wraparound on 16-bit machine */
- s->lookahead = (uInt)(s->strstart - max_start);
- s->strstart = (uInt)max_start;
- FLUSH_BLOCK(s, 0);
- }
- /* Flush if we may have to slide, otherwise block_start may become
- * negative and the data will be gone:
- */
- if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
- FLUSH_BLOCK(s, 0);
- }
- }
- FLUSH_BLOCK(s, flush == Z_FINISH);
- return flush == Z_FINISH ? finish_done : block_done;
-}
-
-/* ===========================================================================
- * Compress as much as possible from the input stream, return the current
- * block state.
- * This function does not perform lazy evaluation of matches and inserts
- * 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(s, flush)
- deflate_state *s;
- int flush;
-{
- IPos hash_head = NIL; /* head of the hash chain */
- int bflush; /* set if current block must be flushed */
-
- for (;;) {
- /* Make sure that we always have enough lookahead, except
- * at the end of the input file. We need MAX_MATCH bytes
- * for the next match, plus MIN_MATCH bytes to insert the
- * string following the next match.
- */
- if (s->lookahead < MIN_LOOKAHEAD) {
- fill_window(s);
- if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
- return need_more;
- }
- if (s->lookahead == 0) break; /* flush the current block */
- }
-
- /* Insert the string window[strstart .. strstart+2] in the
- * dictionary, and set hash_head to the head of the hash chain:
- */
- if (s->lookahead >= MIN_MATCH) {
- INSERT_STRING(s, s->strstart, hash_head);
- }
-
- /* Find the longest match, discarding those <= prev_length.
- * At this point we have always match_length < MIN_MATCH
- */
- if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
- /* 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).
- */
- if (s->strategy != Z_HUFFMAN_ONLY) {
- 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);
-
- _tr_tally_dist(s, s->strstart - s->match_start,
- s->match_length - MIN_MATCH, bflush);
-
- s->lookahead -= s->match_length;
-
- /* Insert new strings in the hash table only if the match length
- * is not too large. This saves time but degrades compression.
- */
-#ifndef FASTEST
- if (s->match_length <= s->max_insert_length &&
- s->lookahead >= MIN_MATCH) {
- s->match_length--; /* string at strstart already in hash table */
- do {
- s->strstart++;
- INSERT_STRING(s, s->strstart, hash_head);
- /* strstart never exceeds WSIZE-MAX_MATCH, so there are
- * always MIN_MATCH bytes ahead.
- */
- } while (--s->match_length != 0);
- s->strstart++;
- } else
-#endif
- {
- s->strstart += s->match_length;
- s->match_length = 0;
- s->ins_h = s->window[s->strstart];
- UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
-#if MIN_MATCH != 3
- Call UPDATE_HASH() MIN_MATCH-3 more times
-#endif
- /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
- * matter since it will be recomputed at next deflate call.
- */
- }
- } else {
- /* No match, output a literal byte */
- 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;
-}
-
-/* ===========================================================================
- * Same as above, but achieves better compression. We use a lazy
- * 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(s, flush)
- deflate_state *s;
- int flush;
-{
- IPos hash_head = NIL; /* head of hash chain */
- int bflush; /* set if current block must be flushed */
-
- /* Process the input block. */
- for (;;) {
- /* Make sure that we always have enough lookahead, except
- * at the end of the input file. We need MAX_MATCH bytes
- * for the next match, plus MIN_MATCH bytes to insert the
- * string following the next match.
- */
- if (s->lookahead < MIN_LOOKAHEAD) {
- fill_window(s);
- if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
- return need_more;
- }
- if (s->lookahead == 0) break; /* flush the current block */
- }
-
- /* Insert the string window[strstart .. strstart+2] in the
- * dictionary, and set hash_head to the head of the hash chain:
- */
- if (s->lookahead >= MIN_MATCH) {
- INSERT_STRING(s, s->strstart, hash_head);
- }
-
- /* Find the longest match, discarding those <= prev_length.
- */
- s->prev_length = s->match_length, s->prev_match = s->match_start;
- s->match_length = MIN_MATCH-1;
-
- if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
- s->strstart - hash_head <= MAX_DIST(s)) {
- /* 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).
- */
- if (s->strategy != Z_HUFFMAN_ONLY) {
- s->match_length = longest_match (s, hash_head);
- }
- /* longest_match() sets match_start */
-
- if (s->match_length <= 5 && (s->strategy == Z_FILTERED ||
- (s->match_length == MIN_MATCH &&
- s->strstart - s->match_start > TOO_FAR))) {
-
- /* If prev_match is also MIN_MATCH, match_start is garbage
- * but we will ignore the current match anyway.
- */
- s->match_length = MIN_MATCH-1;
- }
- }
- /* If there was a match at the previous step and the current
- * match is not better, output the previous match:
- */
- if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
- uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
- /* Do not insert strings in hash table beyond this. */
-
- check_match(s, s->strstart-1, s->prev_match, s->prev_length);
-
- _tr_tally_dist(s, s->strstart -1 - s->prev_match,
- s->prev_length - MIN_MATCH, bflush);
-
- /* Insert in hash table all strings up to the end of the match.
- * strstart-1 and strstart are already inserted. If there is not
- * enough lookahead, the last two strings are not inserted in
- * the hash table.
- */
- s->lookahead -= s->prev_length-1;
- s->prev_length -= 2;
- do {
- if (++s->strstart <= max_insert) {
- INSERT_STRING(s, s->strstart, hash_head);
- }
- } while (--s->prev_length != 0);
- s->match_available = 0;
- s->match_length = MIN_MATCH-1;
- s->strstart++;
-
- if (bflush) FLUSH_BLOCK(s, 0);
-
- } else if (s->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", s->window[s->strstart-1]));
- _tr_tally_lit(s, s->window[s->strstart-1], bflush);
- if (bflush) {
- FLUSH_BLOCK_ONLY(s, 0);
- }
- s->strstart++;
- s->lookahead--;
- if (s->strm->avail_out == 0) return need_more;
- } else {
- /* There is no previous match to compare with, wait for
- * the next step to decide.
- */
- s->match_available = 1;
- s->strstart++;
- s->lookahead--;
- }
- }
- Assert (flush != Z_NO_FLUSH, "no flush?");
- if (s->match_available) {
- Tracevv((stderr,"%c", s->window[s->strstart-1]));
- _tr_tally_lit(s, s->window[s->strstart-1], bflush);
- s->match_available = 0;
- }
- FLUSH_BLOCK(s, flush == Z_FINISH);
- return flush == Z_FINISH ? finish_done : block_done;
-}
+/* deflate.c -- compress data using the deflation algorithm + * Copyright (C) 1995-2002 Jean-loup Gailly. + * For conditions of distribution and use, see copyright notice in zlib.h + */ + +/* + * ALGORITHM + * + * The "deflation" process depends on being able to identify portions + * of the input text which are identical to earlier input (within a + * sliding window trailing behind the input currently being processed). + * + * The most straightforward technique turns out to be the fastest for + * most input files: try all possible matches and select the longest. + * The key feature of this algorithm is that insertions into the string + * dictionary are very simple and thus fast, and deletions are avoided + * completely. Insertions are performed at each input character, whereas + * string matches are performed only when the previous match ends. So it + * is preferable to spend more time in matches to allow very fast string + * insertions and avoid deletions. The matching algorithm for small + * strings is inspired from that of Rabin & Karp. A brute force approach + * is used to find longer strings when a small match has been found. + * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze + * (by Leonid Broukhis). + * A previous version of this file used a more sophisticated algorithm + * (by Fiala and Greene) which is guaranteed to run in linear amortized + * time, but has a larger average cost, uses more memory and is patented. + * However the F&G algorithm may be faster for some highly redundant + * files if the parameter max_chain_length (described below) is too large. + * + * ACKNOWLEDGEMENTS + * + * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and + * I found it in 'freeze' written by Leonid Broukhis. + * Thanks to many people for bug reports and testing. + * + * REFERENCES + * + * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". + * Available in ftp://ds.internic.net/rfc/rfc1951.txt + * + * A description of the Rabin and Karp algorithm is given in the book + * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. + * + * Fiala,E.R., and Greene,D.H. + * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 + * + */ + +/* @(#) $Id: deflate.c,v 1.3 2004-11-27 21:46:13 pixel Exp $ */ + +#include "deflate.h" + +const char deflate_copyright[] = + " deflate 1.1.4 Copyright 1995-2002 Jean-loup Gailly "; +/* + 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 + include such an acknowledgment, I would appreciate that you keep this + copyright string in the executable of your product. + */ + +/* =========================================================================== + * Function prototypes. + */ +typedef enum { + need_more, /* block not completed, need more input or more output */ + block_done, /* block flush performed */ + finish_started, /* finish started, need only more output at next deflate */ + finish_done /* finish done, accept no more input or output */ +} block_state; + +typedef block_state (*compress_func) OF((deflate_state *s, int flush)); +/* Compression function. Returns the block state after the call. */ + +local void fill_window OF((deflate_state *s)); +local block_state deflate_stored OF((deflate_state *s, int flush)); +local block_state deflate_fast OF((deflate_state *s, int flush)); +local block_state deflate_slow 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)); +#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 + +#ifdef DEBUG +local void check_match OF((deflate_state *s, IPos start, IPos match, + int length)); +#endif + +/* =========================================================================== + * Local data + */ + +#define NIL 0 +/* Tail of hash chains */ + +#ifndef TOO_FAR +# define TOO_FAR 4096 +#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 + * found for specific files. + */ +typedef struct config_s { + ush good_length; /* reduce lazy search above this match length */ + ush max_lazy; /* do not perform lazy search above this match length */ + ush nice_length; /* quit search above this match length */ + ush max_chain; + compress_func func; +} config; + +local const config configuration_table[10] = { +/* good lazy nice chain */ +/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */ +/* 1 */ {4, 4, 8, 4, deflate_fast}, /* maximum speed, no lazy matches */ +/* 2 */ {4, 5, 16, 8, deflate_fast}, +/* 3 */ {4, 6, 32, 32, deflate_fast}, + +/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */ +/* 5 */ {8, 16, 32, 32, deflate_slow}, +/* 6 */ {8, 16, 128, 128, deflate_slow}, +/* 7 */ {8, 32, 128, 256, deflate_slow}, +/* 8 */ {32, 128, 258, 1024, deflate_slow}, +/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* maximum compression */ + +/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4 + * For deflate_fast() (levels <= 3) good is ignored and lazy has a different + * meaning. + */ + +#define EQUAL 0 +/* result of memcmp for equal strings */ + +struct static_tree_desc_s {int dummy;}; /* for buggy compilers */ + +/* =========================================================================== + * Update a hash value with the given input byte + * IN assertion: all calls to 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. + */ +#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask) + + +/* =========================================================================== + * Insert string str 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. + * If this file is compiled with -DFASTEST, the compression level is forced + * to 1, and no hash chains are maintained. + * IN assertion: all calls to to INSERT_STRING are made with consecutive + * input characters and the first MIN_MATCH bytes of str are valid + * (except for the last MIN_MATCH-1 bytes of the input file). + */ +#ifdef FASTEST +#define INSERT_STRING(s, str, match_head) \ + (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ + match_head = s->head[s->ins_h], \ + s->head[s->ins_h] = (Pos)(str)) +#else +#define INSERT_STRING(s, str, match_head) \ + (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \ + s->prev[(str) & s->w_mask] = match_head = s->head[s->ins_h], \ + s->head[s->ins_h] = (Pos)(str)) +#endif + +/* =========================================================================== + * Initialize the hash table (avoiding 64K overflow for 16 bit systems). + * prev[] will be initialized on the fly. + */ +#define CLEAR_HASH(s) \ + s->head[s->hash_size-1] = NIL; \ + zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head)); + +/* ========================================================================= */ +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); + /* To do: ignore strm->next_in if we use it as window */ +} + +/* ========================================================================= */ +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 noheader = 0; + static const char* my_version = ZLIB_VERSION; + + ushf *overlay; + /* We overlay pending_buf and d_buf+l_buf. This works since the average + * output size for (length,distance) codes is <= 24 bits. + */ + + if (version == Z_NULL || version[0] != my_version[0] || + stream_size != sizeof(z_stream)) { + return Z_VERSION_ERROR; + } + if (strm == Z_NULL) return Z_STREAM_ERROR; + + strm->msg = Z_NULL; + if (strm->zalloc == Z_NULL) { + strm->zalloc = zcalloc; + strm->opaque = (voidpf)0; + } + if (strm->zfree == Z_NULL) strm->zfree = zcfree; + + if (level == Z_DEFAULT_COMPRESSION) level = 6; +#ifdef FASTEST + level = 1; +#endif + + if (windowBits < 0) { /* undocumented feature: suppress zlib header */ + noheader = 1; + windowBits = -windowBits; + } + if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || + windowBits < 9 || windowBits > 15 || level < 0 || level > 9 || + strategy < 0 || strategy > Z_HUFFMAN_ONLY) { + return Z_STREAM_ERROR; + } + s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); + if (s == Z_NULL) return Z_MEM_ERROR; + strm->state = (struct internal_state FAR *)s; + s->strm = strm; + + s->noheader = noheader; + s->w_bits = windowBits; + s->w_size = 1 << s->w_bits; + s->w_mask = s->w_size - 1; + + s->hash_bits = memLevel + 7; + s->hash_size = 1 << s->hash_bits; + s->hash_mask = s->hash_size - 1; + s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH); + + s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); + s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); + s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); + + s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ + + overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2); + s->pending_buf = (uchf *) overlay; + s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L); + + if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || + s->pending_buf == Z_NULL) { + strm->msg = (char*)ERR_MSG(Z_MEM_ERROR); + deflateEnd (strm); + return Z_MEM_ERROR; + } + s->d_buf = overlay + s->lit_bufsize/sizeof(ush); + s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize; + + s->level = level; + s->strategy = strategy; + s->method = (Byte)method; + + return deflateReset(strm); +} + +/* ========================================================================= */ +int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength) + z_streamp strm; + const Bytef *dictionary; + uInt dictLength; +{ + deflate_state *s; + uInt length = dictLength; + uInt n; + IPos hash_head = 0; + + if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL || + strm->state->status != INIT_STATE) return Z_STREAM_ERROR; + + s = strm->state; + strm->adler = adler32(strm->adler, dictionary, dictLength); + + if (length < MIN_MATCH) return Z_OK; + if (length > MAX_DIST(s)) { + length = MAX_DIST(s); +#ifndef USE_DICT_HEAD + dictionary += dictLength - length; /* use the tail of the dictionary */ +#endif + } + zmemcpy(s->window, dictionary, length); + s->strstart = length; + s->block_start = (long)length; + + /* Insert all strings in the hash table (except for the last two bytes). + * s->lookahead stays null, so s->ins_h will be recomputed at the next + * call of fill_window. + */ + s->ins_h = s->window[0]; + UPDATE_HASH(s, s->ins_h, s->window[1]); + for (n = 0; n <= length - MIN_MATCH; n++) { + INSERT_STRING(s, n, hash_head); + } + if (hash_head) hash_head = 0; /* to make compiler happy */ + return Z_OK; +} + +/* ========================================================================= */ +int ZEXPORT deflateReset (strm) + z_streamp strm; +{ + deflate_state *s; + + if (strm == Z_NULL || strm->state == Z_NULL || + strm->zalloc == Z_NULL || strm->zfree == Z_NULL) return Z_STREAM_ERROR; + + strm->total_in = strm->total_out = 0; + strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ + strm->data_type = Z_UNKNOWN; + + s = (deflate_state *)strm->state; + s->pending = 0; + s->pending_out = s->pending_buf; + + if (s->noheader < 0) { + s->noheader = 0; /* was set to -1 by deflate(..., Z_FINISH); */ + } + s->status = s->noheader ? BUSY_STATE : INIT_STATE; + strm->adler = 1; + s->last_flush = Z_NO_FLUSH; + + _tr_init(s); + lm_init(s); + + return Z_OK; +} + +/* ========================================================================= */ +int ZEXPORT deflateParams(strm, level, strategy) + z_streamp strm; + int level; + int strategy; +{ + deflate_state *s; + compress_func func; + int err = Z_OK; + + if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; + s = strm->state; + + if (level == Z_DEFAULT_COMPRESSION) { + level = 6; + } + if (level < 0 || level > 9 || strategy < 0 || strategy > Z_HUFFMAN_ONLY) { + return Z_STREAM_ERROR; + } + func = configuration_table[s->level].func; + + if (func != configuration_table[level].func && strm->total_in != 0) { + /* Flush the last buffer: */ + err = deflate(strm, Z_PARTIAL_FLUSH); + } + if (s->level != level) { + s->level = level; + s->max_lazy_match = configuration_table[level].max_lazy; + s->good_match = configuration_table[level].good_length; + s->nice_match = configuration_table[level].nice_length; + s->max_chain_length = configuration_table[level].max_chain; + } + s->strategy = strategy; + return err; +} + +/* ========================================================================= + * Put a short in the pending buffer. The 16-bit value is put in MSB order. + * IN assertion: the stream state is correct and there is enough room in + * pending_buf. + */ +local void putShortMSB (s, b) + deflate_state *s; + uInt b; +{ + put_byte(s, (Byte)(b >> 8)); + put_byte(s, (Byte)(b & 0xff)); +} + +/* ========================================================================= + * Flush as much pending output as possible. All deflate() output goes + * through this function so some applications may wish to modify it + * to avoid allocating a large strm->next_out buffer and copying into it. + * (See also read_buf()). + */ +local void flush_pending(strm) + z_streamp strm; +{ + unsigned len = strm->state->pending; + + if (len > strm->avail_out) len = strm->avail_out; + if (len == 0) return; + + zmemcpy(strm->next_out, strm->state->pending_out, len); + strm->next_out += len; + strm->state->pending_out += len; + strm->total_out += len; + strm->avail_out -= len; + strm->state->pending -= len; + if (strm->state->pending == 0) { + strm->state->pending_out = strm->state->pending_buf; + } +} + +/* ========================================================================= */ +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) { + return Z_STREAM_ERROR; + } + s = strm->state; + + if (strm->next_out == Z_NULL || + (strm->next_in == Z_NULL && strm->avail_in != 0) || + (s->status == FINISH_STATE && flush != Z_FINISH)) { + ERR_RETURN(strm, Z_STREAM_ERROR); + } + if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); + + s->strm = strm; /* just in case */ + old_flush = s->last_flush; + s->last_flush = flush; + + /* Write the zlib header */ + if (s->status == INIT_STATE) { + + uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8; + uInt level_flags = (s->level-1) >> 1; + + if (level_flags > 3) level_flags = 3; + header |= (level_flags << 6); + if (s->strstart != 0) header |= PRESET_DICT; + header += 31 - (header % 31); + + s->status = BUSY_STATE; + putShortMSB(s, header); + + /* Save the adler32 of the preset dictionary: */ + if (s->strstart != 0) { + putShortMSB(s, (uInt)(strm->adler >> 16)); + putShortMSB(s, (uInt)(strm->adler & 0xffff)); + } + strm->adler = 1L; + } + + /* Flush as much pending output as possible */ + if (s->pending != 0) { + flush_pending(strm); + if (strm->avail_out == 0) { + /* Since avail_out is 0, deflate will be called again with + * more output space, but possibly with both pending and + * avail_in equal to zero. There won't be anything to do, + * but this is not an error situation so make sure we + * return OK instead of BUF_ERROR at next call of deflate: + */ + s->last_flush = -1; + return Z_OK; + } + + /* Make sure there is something to do and avoid duplicate consecutive + * flushes. For repeated and useless calls with Z_FINISH, we keep + * returning Z_STREAM_END instead of Z_BUFF_ERROR. + */ + } else if (strm->avail_in == 0 && flush <= old_flush && + flush != Z_FINISH) { + ERR_RETURN(strm, Z_BUF_ERROR); + } + + /* User must not provide more input after the first FINISH: */ + if (s->status == FINISH_STATE && strm->avail_in != 0) { + ERR_RETURN(strm, Z_BUF_ERROR); + } + + /* Start a new block or continue the current one. + */ + if (strm->avail_in != 0 || s->lookahead != 0 || + (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { + block_state bstate; + + bstate = (*(configuration_table[s->level].func))(s, flush); + + if (bstate == finish_started || bstate == finish_done) { + s->status = FINISH_STATE; + } + if (bstate == need_more || bstate == finish_started) { + if (strm->avail_out == 0) { + s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ + } + return Z_OK; + /* If flush != Z_NO_FLUSH && avail_out == 0, the next call + * of deflate should use the same flush parameter to make sure + * that the flush is complete. So we don't have to output an + * empty block here, this will be done at next call. This also + * ensures that for a very small output buffer, we emit at most + * one empty block. + */ + } + if (bstate == block_done) { + if (flush == Z_PARTIAL_FLUSH) { + _tr_align(s); + } else { /* 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 */ + } + } + flush_pending(strm); + if (strm->avail_out == 0) { + s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ + return Z_OK; + } + } + } + Assert(strm->avail_out > 0, "bug2"); + + if (flush != Z_FINISH) return Z_OK; + if (s->noheader) return Z_STREAM_END; + + /* Write the zlib trailer (adler32) */ + putShortMSB(s, (uInt)(strm->adler >> 16)); + putShortMSB(s, (uInt)(strm->adler & 0xffff)); + flush_pending(strm); + /* If avail_out is zero, the application will call deflate again + * to flush the rest. + */ + s->noheader = -1; /* write the trailer only once! */ + return s->pending != 0 ? Z_OK : Z_STREAM_END; +} + +/* ========================================================================= */ +int ZEXPORT deflateEnd (strm) + z_streamp strm; +{ + int status; + + if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR; + + status = strm->state->status; + if (status != INIT_STATE && status != BUSY_STATE && + status != FINISH_STATE) { + return Z_STREAM_ERROR; + } + + /* Deallocate in reverse order of allocations: */ + TRY_FREE(strm, strm->state->pending_buf); + TRY_FREE(strm, strm->state->head); + TRY_FREE(strm, strm->state->prev); + TRY_FREE(strm, strm->state->window); + + ZFREE(strm, strm->state); + strm->state = Z_NULL; + + return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; +} + +/* ========================================================================= + * Copy the source state to the destination state. + * 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 (dest, source) + z_streamp dest; + z_streamp source; +{ +#ifdef MAXSEG_64K + return Z_STREAM_ERROR; +#else + deflate_state *ds; + deflate_state *ss; + ushf *overlay; + + + if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) { + return Z_STREAM_ERROR; + } + + ss = source->state; + + *dest = *source; + + ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); + if (ds == Z_NULL) return Z_MEM_ERROR; + dest->state = (struct internal_state FAR *) ds; + *ds = *ss; + ds->strm = dest; + + ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); + ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); + ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); + overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2); + ds->pending_buf = (uchf *) overlay; + + if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || + ds->pending_buf == Z_NULL) { + deflateEnd (dest); + return Z_MEM_ERROR; + } + /* following zmemcpy do not work for 16-bit MSDOS */ + zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte)); + zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos)); + zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); + zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size); + + ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); + ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush); + ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize; + + ds->l_desc.dyn_tree = ds->dyn_ltree; + ds->d_desc.dyn_tree = ds->dyn_dtree; + ds->bl_desc.dyn_tree = ds->bl_tree; + + return Z_OK; +#endif +} + +/* =========================================================================== + * Read a new buffer from the current input stream, update the adler32 + * and total number of bytes read. All deflate() input goes through + * this function so some applications may wish to modify it to avoid + * allocating a large strm->next_in buffer and copying from it. + * (See also flush_pending()). + */ +local int read_buf(strm, buf, size) + z_streamp strm; + Bytef *buf; + unsigned size; +{ + unsigned len = strm->avail_in; + + if (len > size) len = size; + if (len == 0) return 0; + + strm->avail_in -= len; + + if (!strm->state->noheader) { + strm->adler = adler32(strm->adler, strm->next_in, len); + } + zmemcpy(buf, strm->next_in, len); + strm->next_in += len; + strm->total_in += len; + + return (int)len; +} + +/* =========================================================================== + * Initialize the "longest match" routines for a new zlib stream + */ +local void lm_init (s) + deflate_state *s; +{ + s->window_size = (ulg)2L*s->w_size; + + CLEAR_HASH(s); + + /* Set the default configuration parameters: + */ + s->max_lazy_match = configuration_table[s->level].max_lazy; + s->good_match = configuration_table[s->level].good_length; + s->nice_match = configuration_table[s->level].nice_length; + s->max_chain_length = configuration_table[s->level].max_chain; + + s->strstart = 0; + s->block_start = 0L; + s->lookahead = 0; + s->match_length = s->prev_length = MIN_MATCH-1; + s->match_available = 0; + s->ins_h = 0; +#ifdef ASMV + match_init(); /* initialize the asm code */ +#endif +} + +/* =========================================================================== + * Set match_start to the longest match starting at the given string and + * return its length. Matches shorter or equal to prev_length are discarded, + * in which case the result is equal to prev_length and match_start is + * garbage. + * IN assertions: cur_match is the head of the hash chain for the current + * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 + * OUT assertion: the match length is not greater than s->lookahead. + */ +#ifndef ASMV +/* For 80x86 and 680x0, an optimized version will be provided in match.asm or + * match.S. The code will be functionally equivalent. + */ +#ifndef FASTEST +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 */ + register Bytef *match; /* matched string */ + register int len; /* length of current match */ + int best_len = s->prev_length; /* best match length so far */ + int nice_match = s->nice_match; /* stop if match long enough */ + IPos limit = s->strstart > (IPos)MAX_DIST(s) ? + s->strstart - (IPos)MAX_DIST(s) : NIL; + /* Stop when cur_match becomes <= limit. To simplify the code, + * we prevent matches with the string of window index 0. + */ + Posf *prev = s->prev; + uInt wmask = s->w_mask; + +#ifdef UNALIGNED_OK + /* Compare two bytes at a time. Note: this is not always beneficial. + * Try with and without -DUNALIGNED_OK to check. + */ + register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; + register ush scan_start = *(ushf*)scan; + register ush scan_end = *(ushf*)(scan+best_len-1); +#else + register Bytef *strend = s->window + s->strstart + MAX_MATCH; + register Byte scan_end1 = scan[best_len-1]; + register Byte scan_end = scan[best_len]; +#endif + + /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. + * It is easy to get rid of this optimization if necessary. + */ + Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); + + /* Do not waste too much time if we already have a good match: */ + if (s->prev_length >= s->good_match) { + chain_length >>= 2; + } + /* Do not look for matches beyond the end of the input. This is necessary + * to make deflate deterministic. + */ + if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead; + + Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); + + do { + Assert(cur_match < s->strstart, "no future"); + match = s->window + 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) + /* This code assumes sizeof(unsigned short) == 2. Do not use + * UNALIGNED_OK if your compiler uses a different size. + */ + if (*(ushf*)(match+best_len-1) != scan_end || + *(ushf*)match != scan_start) continue; + + /* It is not necessary to compare scan[2] and match[2] since they are + * always equal when the other bytes match, given that the hash keys + * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at + * strstart+3, +5, ... up to strstart+257. We check for insufficient + * lookahead only every 4th comparison; the 128th check will be made + * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is + * necessary to put more guard bytes at the end of the window, or + * to check more often for insufficient lookahead. + */ + Assert(scan[2] == match[2], "scan[2]?"); + scan++, match++; + do { + } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) && + *(ushf*)(scan+=2) == *(ushf*)(match+=2) && + *(ushf*)(scan+=2) == *(ushf*)(match+=2) && + *(ushf*)(scan+=2) == *(ushf*)(match+=2) && + scan < strend); + /* The funny "do {}" generates better code on most compilers */ + + /* Here, scan <= window+strstart+257 */ + Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); + if (*scan == *match) scan++; + + len = (MAX_MATCH - 1) - (int)(strend-scan); + scan = strend - (MAX_MATCH-1); + +#else /* UNALIGNED_OK */ + + if (match[best_len] != scan_end || + match[best_len-1] != scan_end1 || + *match != *scan || + *++match != scan[1]) continue; + + /* The check at best_len-1 can be removed because it will be made + * again later. (This heuristic is not always a win.) + * It is not necessary to compare scan[2] and match[2] since they + * are always equal when the other bytes match, given that + * the hash keys are equal and that HASH_BITS >= 8. + */ + scan += 2, match++; + Assert(*scan == *match, "match[2]?"); + + /* We check for insufficient lookahead only every 8th comparison; + * the 256th check will be made at strstart+258. + */ + do { + } while (*++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + scan < strend); + + Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); + + len = MAX_MATCH - (int)(strend - scan); + scan = strend - MAX_MATCH; + +#endif /* UNALIGNED_OK */ + + if (len > best_len) { + s->match_start = cur_match; + best_len = len; + if (len >= nice_match) break; +#ifdef UNALIGNED_OK + scan_end = *(ushf*)(scan+best_len-1); +#else + scan_end1 = scan[best_len-1]; + scan_end = scan[best_len]; +#endif + } + } while ((cur_match = prev[cur_match & wmask]) > limit + && --chain_length != 0); + + if ((uInt)best_len <= s->lookahead) return (uInt)best_len; + return s->lookahead; +} + +#else /* FASTEST */ +/* --------------------------------------------------------------------------- + * Optimized version for level == 1 only + */ +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 */ + register int len; /* length of current match */ + register Bytef *strend = s->window + s->strstart + MAX_MATCH; + + /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. + * It is easy to get rid of this optimization if necessary. + */ + Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); + + Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead"); + + Assert(cur_match < s->strstart, "no future"); + + match = s->window + cur_match; + + /* Return failure if the match length is less than 2: + */ + if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; + + /* The check at best_len-1 can be removed because it will be made + * again later. (This heuristic is not always a win.) + * It is not necessary to compare scan[2] and match[2] since they + * are always equal when the other bytes match, given that + * the hash keys are equal and that HASH_BITS >= 8. + */ + scan += 2, match += 2; + Assert(*scan == *match, "match[2]?"); + + /* We check for insufficient lookahead only every 8th comparison; + * the 256th check will be made at strstart+258. + */ + do { + } while (*++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + *++scan == *++match && *++scan == *++match && + scan < strend); + + Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan"); + + len = MAX_MATCH - (int)(strend - scan); + + if (len < MIN_MATCH) return MIN_MATCH - 1; + + s->match_start = cur_match; + return len <= s->lookahead ? len : s->lookahead; +} +#endif /* FASTEST */ +#endif /* ASMV */ + +#ifdef DEBUG +/* =========================================================================== + * Check that the match at match_start is indeed a match. + */ +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, + s->window + start, length) != EQUAL) { + fprintf(stderr, " start %u, match %u, length %d\n", + start, match, length); + do { + fprintf(stderr, "%c%c", s->window[match++], s->window[start++]); + } while (--length != 0); + z_error("invalid match"); + } + if (z_verbose > 1) { + fprintf(stderr,"\\[%d,%d]", start-match, length); + do { putc(s->window[start++], stderr); } while (--length != 0); + } +} +#else +# define check_match(s, start, match, length) +#endif + +/* =========================================================================== + * Fill the window when the lookahead becomes insufficient. + * Updates strstart and lookahead. + * + * IN assertion: lookahead < MIN_LOOKAHEAD + * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD + * At least one byte has been read, or avail_in == 0; reads are + * performed for at least two bytes (required for the zip translate_eol + * option -- not supported here). + */ +local void fill_window(s) + deflate_state *s; +{ + register unsigned n, m; + register Posf *p; + unsigned more; /* Amount of free space at the end of the window. */ + uInt wsize = s->w_size; + + do { + more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart); + + /* Deal with !@#$% 64K limit: */ + if (more == 0 && s->strstart == 0 && s->lookahead == 0) { + more = wsize; + + } else if (more == (unsigned)(-1)) { + /* Very unlikely, but possible on 16 bit machine if strstart == 0 + * and lookahead == 1 (input done one byte at time) + */ + more--; + + /* If the window is almost full and there is insufficient lookahead, + * move the upper half to the lower one to make room in the upper half. + */ + } else if (s->strstart >= wsize+MAX_DIST(s)) { + + zmemcpy(s->window, s->window+wsize, (unsigned)wsize); + s->match_start -= wsize; + s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ + s->block_start -= (long) wsize; + + /* Slide the hash table (could be avoided with 32 bit values + at the expense of memory usage). We slide even when level == 0 + to keep the hash table consistent if we switch back to level > 0 + later. (Using level 0 permanently is not an optimal usage of + zlib, so we don't care about this pathological case.) + */ + n = s->hash_size; + p = &s->head[n]; + do { + m = *--p; + *p = (Pos)(m >= wsize ? m-wsize : NIL); + } while (--n); + + n = wsize; +#ifndef FASTEST + p = &s->prev[n]; + do { + m = *--p; + *p = (Pos)(m >= wsize ? m-wsize : NIL); + /* If n is not on any hash chain, prev[n] is garbage but + * its value will never be used. + */ + } while (--n); +#endif + more += wsize; + } + if (s->strm->avail_in == 0) return; + + /* If there was no sliding: + * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && + * more == window_size - lookahead - strstart + * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) + * => more >= window_size - 2*WSIZE + 2 + * In the BIG_MEM or MMAP case (not yet supported), + * window_size == input_size + MIN_LOOKAHEAD && + * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. + * Otherwise, window_size == 2*WSIZE so more >= 2. + * If there was sliding, more >= WSIZE. So in all cases, more >= 2. + */ + Assert(more >= 2, "more < 2"); + + n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); + s->lookahead += n; + + /* Initialize the hash value now that we have some input: */ + if (s->lookahead >= MIN_MATCH) { + s->ins_h = s->window[s->strstart]; + UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); +#if MIN_MATCH != 3 + Call UPDATE_HASH() MIN_MATCH-3 more times +#endif + } + /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, + * but this is not important since only literal bytes will be emitted. + */ + + } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 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_ONLY(s, eof) { \ + _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)); \ + 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; \ +} + +/* =========================================================================== + * Copy without compression as much as possible from the input stream, return + * the current block state. + * This function does not insert new strings in the dictionary since + * uncompressible data is probably not useful. This function is used + * only for the level=0 compression option. + * NOTE: this function should be optimized to avoid extra copying from + * window to pending_buf. + */ +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: + */ + ulg max_block_size = 0xffff; + ulg max_start; + + if (max_block_size > s->pending_buf_size - 5) { + max_block_size = s->pending_buf_size - 5; + } + + /* Copy as much as possible from input to output: */ + for (;;) { + /* Fill the window as much as possible: */ + if (s->lookahead <= 1) { + + Assert(s->strstart < s->w_size+MAX_DIST(s) || + s->block_start >= (long)s->w_size, "slide too late"); + + fill_window(s); + if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more; + + if (s->lookahead == 0) break; /* flush the current block */ + } + Assert(s->block_start >= 0L, "block gone"); + + s->strstart += s->lookahead; + s->lookahead = 0; + + /* Emit a stored block if pending_buf will be full: */ + max_start = s->block_start + max_block_size; + if (s->strstart == 0 || (ulg)s->strstart >= max_start) { + /* strstart == 0 is possible when wraparound on 16-bit machine */ + s->lookahead = (uInt)(s->strstart - max_start); + s->strstart = (uInt)max_start; + FLUSH_BLOCK(s, 0); + } + /* Flush if we may have to slide, otherwise block_start may become + * negative and the data will be gone: + */ + if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) { + FLUSH_BLOCK(s, 0); + } + } + FLUSH_BLOCK(s, flush == Z_FINISH); + return flush == Z_FINISH ? finish_done : block_done; +} + +/* =========================================================================== + * Compress as much as possible from the input stream, return the current + * block state. + * This function does not perform lazy evaluation of matches and inserts + * 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(s, flush) + deflate_state *s; + int flush; +{ + IPos hash_head = NIL; /* head of the hash chain */ + int bflush; /* set if current block must be flushed */ + + for (;;) { + /* Make sure that we always have enough lookahead, except + * at the end of the input file. We need MAX_MATCH bytes + * for the next match, plus MIN_MATCH bytes to insert the + * string following the next match. + */ + if (s->lookahead < MIN_LOOKAHEAD) { + fill_window(s); + if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { + return need_more; + } + if (s->lookahead == 0) break; /* flush the current block */ + } + + /* Insert the string window[strstart .. strstart+2] in the + * dictionary, and set hash_head to the head of the hash chain: + */ + if (s->lookahead >= MIN_MATCH) { + INSERT_STRING(s, s->strstart, hash_head); + } + + /* Find the longest match, discarding those <= prev_length. + * At this point we have always match_length < MIN_MATCH + */ + if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { + /* 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). + */ + if (s->strategy != Z_HUFFMAN_ONLY) { + 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); + + _tr_tally_dist(s, s->strstart - s->match_start, + s->match_length - MIN_MATCH, bflush); + + s->lookahead -= s->match_length; + + /* Insert new strings in the hash table only if the match length + * is not too large. This saves time but degrades compression. + */ +#ifndef FASTEST + if (s->match_length <= s->max_insert_length && + s->lookahead >= MIN_MATCH) { + s->match_length--; /* string at strstart already in hash table */ + do { + s->strstart++; + INSERT_STRING(s, s->strstart, hash_head); + /* strstart never exceeds WSIZE-MAX_MATCH, so there are + * always MIN_MATCH bytes ahead. + */ + } while (--s->match_length != 0); + s->strstart++; + } else +#endif + { + s->strstart += s->match_length; + s->match_length = 0; + s->ins_h = s->window[s->strstart]; + UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]); +#if MIN_MATCH != 3 + Call UPDATE_HASH() MIN_MATCH-3 more times +#endif + /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not + * matter since it will be recomputed at next deflate call. + */ + } + } else { + /* No match, output a literal byte */ + 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; +} + +/* =========================================================================== + * Same as above, but achieves better compression. We use a lazy + * 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(s, flush) + deflate_state *s; + int flush; +{ + IPos hash_head = NIL; /* head of hash chain */ + int bflush; /* set if current block must be flushed */ + + /* Process the input block. */ + for (;;) { + /* Make sure that we always have enough lookahead, except + * at the end of the input file. We need MAX_MATCH bytes + * for the next match, plus MIN_MATCH bytes to insert the + * string following the next match. + */ + if (s->lookahead < MIN_LOOKAHEAD) { + fill_window(s); + if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { + return need_more; + } + if (s->lookahead == 0) break; /* flush the current block */ + } + + /* Insert the string window[strstart .. strstart+2] in the + * dictionary, and set hash_head to the head of the hash chain: + */ + if (s->lookahead >= MIN_MATCH) { + INSERT_STRING(s, s->strstart, hash_head); + } + + /* Find the longest match, discarding those <= prev_length. + */ + s->prev_length = s->match_length, s->prev_match = s->match_start; + s->match_length = MIN_MATCH-1; + + if (hash_head != NIL && s->prev_length < s->max_lazy_match && + s->strstart - hash_head <= MAX_DIST(s)) { + /* 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). + */ + if (s->strategy != Z_HUFFMAN_ONLY) { + s->match_length = longest_match (s, hash_head); + } + /* longest_match() sets match_start */ + + if (s->match_length <= 5 && (s->strategy == Z_FILTERED || + (s->match_length == MIN_MATCH && + s->strstart - s->match_start > TOO_FAR))) { + + /* If prev_match is also MIN_MATCH, match_start is garbage + * but we will ignore the current match anyway. + */ + s->match_length = MIN_MATCH-1; + } + } + /* If there was a match at the previous step and the current + * match is not better, output the previous match: + */ + if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { + uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; + /* Do not insert strings in hash table beyond this. */ + + check_match(s, s->strstart-1, s->prev_match, s->prev_length); + + _tr_tally_dist(s, s->strstart -1 - s->prev_match, + s->prev_length - MIN_MATCH, bflush); + + /* Insert in hash table all strings up to the end of the match. + * strstart-1 and strstart are already inserted. If there is not + * enough lookahead, the last two strings are not inserted in + * the hash table. + */ + s->lookahead -= s->prev_length-1; + s->prev_length -= 2; + do { + if (++s->strstart <= max_insert) { + INSERT_STRING(s, s->strstart, hash_head); + } + } while (--s->prev_length != 0); + s->match_available = 0; + s->match_length = MIN_MATCH-1; + s->strstart++; + + if (bflush) FLUSH_BLOCK(s, 0); + + } else if (s->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", s->window[s->strstart-1])); + _tr_tally_lit(s, s->window[s->strstart-1], bflush); + if (bflush) { + FLUSH_BLOCK_ONLY(s, 0); + } + s->strstart++; + s->lookahead--; + if (s->strm->avail_out == 0) return need_more; + } else { + /* There is no previous match to compare with, wait for + * the next step to decide. + */ + s->match_available = 1; + s->strstart++; + s->lookahead--; + } + } + Assert (flush != Z_NO_FLUSH, "no flush?"); + if (s->match_available) { + Tracevv((stderr,"%c", s->window[s->strstart-1])); + _tr_tally_lit(s, s->window[s->strstart-1], bflush); + s->match_available = 0; + } + FLUSH_BLOCK(s, flush == Z_FINISH); + return flush == Z_FINISH ? finish_done : block_done; +} |