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Diffstat (limited to 'nx-X11/extras/zlib/deflate.c')
| -rw-r--r-- | nx-X11/extras/zlib/deflate.c | 1348 |
1 files changed, 0 insertions, 1348 deletions
diff --git a/nx-X11/extras/zlib/deflate.c b/nx-X11/extras/zlib/deflate.c deleted file mode 100644 index 355e5690b..000000000 --- a/nx-X11/extras/zlib/deflate.c +++ /dev/null @@ -1,1348 +0,0 @@ -/* 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 - * - */ - -#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; -} |