/* deflate.c -- compress data using the deflation algorithm
- * Copyright (C) 1995 Jean-loup Gailly.
+ * Copyright (C) 1995-2003 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
*
* REFERENCES
*
- * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
- * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
+ * 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.
*
*/
-/* $Id: deflate.c,v 1.4 1995/04/14 19:49:46 jloup Exp $ */
+/* @(#) $Id$ */
#include "deflate.h"
-char copyright[] = " deflate Copyright 1995 Jean-loup Gailly ";
+const char deflate_copyright[] =
+ " deflate 1.2.0 Copyright 1995-2003 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
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 */
* 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 config configuration_table[10] = {
+local const config configuration_table[10] = {
/* good lazy nice chain */
-/* 0 */ {0, 0, 0, 0}, /* store only */
-/* 1 */ {4, 4, 8, 4}, /* maximum speed, no lazy matches */
-/* 2 */ {4, 5, 16, 8},
-/* 3 */ {4, 6, 32, 32},
-
-/* 4 */ {4, 4, 16, 16}, /* lazy matches */
-/* 5 */ {8, 16, 32, 32},
-/* 6 */ {8, 16, 128, 128},
-/* 7 */ {8, 32, 128, 256},
-/* 8 */ {32, 128, 258, 1024},
-/* 9 */ {32, 258, 258, 4096}}; /* maximum compression */
+/* 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
struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
-/* ===========================================================================
- * Prototypes for local functions.
- */
-
-local void fill_window __P((deflate_state *s));
-local int deflate_fast __P((deflate_state *s, int flush));
-local int deflate_slow __P((deflate_state *s, int flush));
-local void lm_init __P((deflate_state *s));
-
-local int longest_match __P((deflate_state *s, IPos cur_match));
-#ifdef ASMV
- void match_init __P((void)); /* asm code initialization */
-#endif
-
-#ifdef DEBUG
-local void check_match __P((deflate_state *s, IPos start, IPos match,
- int length));
-#endif
-
-
/* ===========================================================================
* Update a hash value with the given input byte
* IN assertion: all calls to to UPDATE_HASH are made with consecutive
*/
#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]), \
+ (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] = (str))
+ 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 deflateInit (strm, level)
- z_stream *strm;
+int ZEXPORT deflateInit_(strm, level, version, stream_size)
+ z_streamp strm;
int level;
+ const char *version;
+ int stream_size;
{
- return deflateInit2 (strm, level, DEFLATED, WBITS, MEM_LEVEL, 0);
+ 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 deflateInit2 (strm, level, method, windowBits, memLevel, strategy)
- z_stream *strm;
+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;
+ 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;
+ noheader = 1;
+ windowBits = -windowBits;
}
- if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != DEFLATED ||
- windowBits < 8 || windowBits > 15 || level < 1 || level > 9) {
- return Z_STREAM_ERROR;
+ 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 *)s;
+ strm->state = (struct internal_state FAR *)s;
s->strm = strm;
s->noheader = noheader;
s->hash_mask = s->hash_size - 1;
s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
- s->window = (Byte*) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
- s->prev = (Pos*) ZALLOC(strm, s->w_size, sizeof(Pos));
- s->head = (Pos*) ZALLOC(strm, s->hash_size, sizeof(Pos));
+ 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 */
- s->pending_buf = (uch*) ZALLOC(strm, s->lit_bufsize, 2*sizeof(ush));
+ 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 = z_errmsg[1-Z_MEM_ERROR];
- deflateEnd (strm);
- return Z_MEM_ERROR;
+ s->pending_buf == Z_NULL) {
+ s->status = FINISH_STATE;
+ strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
+ deflateEnd (strm);
+ return Z_MEM_ERROR;
}
- s->d_buf = (ush*) &(s->pending_buf[s->lit_bufsize]);
- s->l_buf = (uch*) &(s->pending_buf[3*s->lit_bufsize]);
- /* We overlay pending_buf and d_buf+l_buf. This works since the average
- * output size for (length,distance) codes is <= 32 bits (worst case
- * is 15+15+13=33).
- */
+ 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 = method;
+ s->method = (Byte)method;
return deflateReset(strm);
}
/* ========================================================================= */
-int deflateReset (strm)
- z_stream *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->noheader && strm->state->status != INIT_STATE))
+ return Z_STREAM_ERROR;
+
+ s = strm->state;
+ if (!s->noheader)
+ 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->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 */
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;
- s->adler = 1;
+ strm->adler = 1;
+ s->last_flush = Z_NO_FLUSH;
- ct_init(s);
+ _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 the pending_out buffer. The 16-bit value is put in MSB order.
+ * For the default windowBits of 15 and memLevel of 8, this function returns
+ * a close to exact, as well as small, upper bound on the compressed size.
+ * They are coded as constants here for a reason--if the #define's are
+ * changed, then this function needs to be changed as well. The return
+ * value for 15 and 8 only works for those exact settings.
+ *
+ * For any setting other than those defaults for windowBits and memLevel,
+ * the value returned is a conservative worst case for the maximum expansion
+ * resulting from using fixed blocks instead of stored blocks, which deflate
+ * can emit on compressed data for some combinations of the parameters.
+ *
+ * This function could be more sophisticated to provide closer upper bounds
+ * for every combination of windowBits and memLevel, as well as noheader.
+ * But even the conservative upper bound of about 14% expansion does not
+ * seem onerous for output buffer allocation.
+ */
+uLong ZEXPORT deflateBound(strm, sourceLen)
+ z_streamp strm;
+ uLong sourceLen;
+{
+ deflate_state *s;
+ uLong destLen;
+
+ /* conservative upper bound */
+ destLen = sourceLen +
+ ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 11;
+
+ /* if can't get parameters, return conservative bound */
+ if (strm == Z_NULL || strm->state == Z_NULL)
+ return destLen;
+
+ /* if not default parameters, return conservative bound */
+ s = strm->state;
+ if (s->w_bits != 15 || s->hash_bits != 8 + 7)
+ return destLen;
+
+ /* default settings: return tight bound for that case */
+ return compressBound(sourceLen);
+}
+
+/* =========================================================================
+ * 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
- * the pending_out buffer.
+ * pending_buf.
*/
local void putShortMSB (s, b)
deflate_state *s;
uInt b;
{
- put_byte(s, b >> 8);
- put_byte(s, b & 0xff);
+ put_byte(s, (Byte)(b >> 8));
+ put_byte(s, (Byte)(b & 0xff));
}
/* =========================================================================
- * Flush as much pending output as possible.
+ * 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_stream *strm;
+ z_streamp strm;
{
unsigned len = strm->state->pending;
strm->avail_out -= len;
strm->state->pending -= len;
if (strm->state->pending == 0) {
- strm->state->pending_out = strm->state->pending_buf;
+ strm->state->pending_out = strm->state->pending_buf;
}
}
/* ========================================================================= */
-int deflate (strm, flush)
- z_stream *strm;
+int ZEXPORT deflate (strm, flush)
+ z_streamp strm;
int flush;
{
- if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
-
- if (strm->next_out == Z_NULL || strm->next_in == Z_NULL) {
- ERR_RETURN(strm, Z_STREAM_ERROR);
+ 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);
- strm->state->strm = strm; /* just in case */
+ s->strm = strm; /* just in case */
+ old_flush = s->last_flush;
+ s->last_flush = flush;
/* Write the zlib header */
- if (strm->state->status == INIT_STATE) {
+ if (s->status == INIT_STATE) {
+
+ uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
+ uInt level_flags = (s->level-1) >> 1;
- uInt header = (DEFLATED + ((strm->state->w_bits-8)<<4)) << 8;
- uInt level_flags = (strm->state->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);
- if (level_flags > 3) level_flags = 3;
- header |= (level_flags << 6);
- header += 31 - (header % 31);
+ s->status = BUSY_STATE;
+ putShortMSB(s, header);
- strm->state->status = BUSY_STATE;
- putShortMSB(strm->state, 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 (strm->state->pending != 0) {
- flush_pending(strm);
- if (strm->avail_out == 0) return Z_OK;
+ 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 (strm->state->status == FINISH_STATE && strm->avail_in != 0) {
- ERR_RETURN(strm, Z_BUF_ERROR);
+ 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 ||
- (flush == Z_FINISH && strm->state->status != FINISH_STATE)) {
-
- if (flush == Z_FINISH) {
- strm->state->status = FINISH_STATE;
- }
- if (strm->state->level <= 3) {
- if (deflate_fast(strm->state, flush)) return Z_OK;
- } else {
- if (deflate_slow(strm->state, flush)) return Z_OK;
+ 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 || strm->state->noheader) return Z_OK;
+ if (flush != Z_FINISH) return Z_OK;
+ if (s->noheader) return Z_STREAM_END;
/* Write the zlib trailer (adler32) */
- putShortMSB(strm->state, strm->state->adler >> 16);
- putShortMSB(strm->state, strm->state->adler & 0xffff);
+ 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.
*/
- strm->state->noheader = 1; /* write the trailer only once! */
- return Z_OK;
+ s->noheader = -1; /* write the trailer only once! */
+ return s->pending != 0 ? Z_OK : Z_STREAM_END;
}
/* ========================================================================= */
-int deflateEnd (strm)
- z_stream *strm;
+int ZEXPORT deflateEnd (strm)
+ z_streamp strm;
{
+ int status;
+
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
- TRY_FREE(strm, strm->state->window);
- TRY_FREE(strm, strm->state->prev);
- TRY_FREE(strm, strm->state->head);
+ 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 Z_OK;
+ return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
}
-/* ========================================================================= */
-int deflateCopy (dest, source)
- z_stream *dest;
- z_stream *source;
+/* =========================================================================
+ * 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;
+ return Z_STREAM_ERROR;
}
+
+ ss = source->state;
+
*dest = *source;
- return Z_STREAM_ERROR; /* to be implemented */
-#if 0
- dest->state = (struct internal_state *)
- (*dest->zalloc)(1, sizeof(deflate_state));
- if (dest->state == Z_NULL) return Z_MEM_ERROR;
- *(dest->state) = *(source->state);
+ 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.
+ * 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_stream *strm;
- char *buf;
+ z_streamp strm;
+ Bytef *buf;
unsigned size;
{
unsigned len = strm->avail_in;
strm->avail_in -= len;
if (!strm->state->noheader) {
- strm->state->adler = adler32(strm->state->adler, strm->next_in, len);
+ strm->adler = adler32(strm->adler, strm->next_in, len);
}
zmemcpy(buf, strm->next_in, len);
strm->next_in += len;
local void lm_init (s)
deflate_state *s;
{
- register unsigned j;
-
s->window_size = (ulg)2L*s->w_size;
-
- /* Initialize the hash table (avoiding 64K overflow for 16 bit systems).
- * prev[] will be initialized on the fly.
- */
- s->head[s->hash_size-1] = NIL;
- zmemzero((char*)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
+ CLEAR_HASH(s);
/* Set the default configuration parameters:
*/
s->strstart = 0;
s->block_start = 0L;
s->lookahead = 0;
- s->match_length = MIN_MATCH-1;
+ 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
-
- s->ins_h = 0;
- for (j=0; j<MIN_MATCH-1; j++) UPDATE_HASH(s, s->ins_h, s->window[j]);
- /* If lookahead < MIN_MATCH, ins_h is garbage, but this is
- * not important since only literal bytes will be emitted.
- */
}
/* ===========================================================================
* 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.
*/
-local int longest_match(s, cur_match)
+#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 Byte *scan = s->window + s->strstart; /* current string */
- register Byte *match; /* matched string */
+ 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;
+ 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 Byte *strend = s->window + s->strstart + MAX_MATCH - 1;
- register ush scan_start = *(ush*)scan;
- register ush scan_end = *(ush*)(scan+best_len-1);
+ 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 Byte *strend = s->window + s->strstart + MAX_MATCH;
+ 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
if (s->prev_length >= s->good_match) {
chain_length >>= 2;
}
- Assert(s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
+ /* 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");
/* This code assumes sizeof(unsigned short) == 2. Do not use
* UNALIGNED_OK if your compiler uses a different size.
*/
- if (*(ush*)(match+best_len-1) != scan_end ||
- *(ush*)match != scan_start) continue;
+ 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
* 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 (*(ush*)(scan+=2) == *(ush*)(match+=2) &&
- *(ush*)(scan+=2) == *(ush*)(match+=2) &&
- *(ush*)(scan+=2) == *(ush*)(match+=2) &&
- *(ush*)(scan+=2) == *(ush*)(match+=2) &&
+ } 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 */
* 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.
if (len > best_len) {
s->match_start = cur_match;
best_len = len;
- if (len >= s->nice_match) break;
+ if (len >= nice_match) break;
#ifdef UNALIGNED_OK
- scan_end = *(ush*)(scan+best_len-1);
+ scan_end = *(ushf*)(scan+best_len-1);
#else
scan_end1 = scan[best_len-1];
scan_end = scan[best_len];
#endif
}
- } while ((cur_match = s->prev[cur_match & s->w_mask]) > limit
+ } while ((cur_match = prev[cur_match & wmask]) > limit
&& --chain_length != 0);
- return best_len;
+ 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
int length;
{
/* check that the match is indeed a match */
- if (memcmp((char*)s->window + match,
- (char*)s->window + start, length) != EQUAL) {
- fprintf(stderr,
- " start %d, match %d, length %d\n",
- start, match, length);
+ 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 (verbose > 1) {
- fprintf(stderr,"\\[%d,%d]", start-match, length);
- do { putc(s->window[start++], stderr); } while (--length != 0);
+ if (z_verbose > 1) {
+ fprintf(stderr,"\\[%d,%d]", start-match, length);
+ do { putc(s->window[start++], stderr); } while (--length != 0);
}
}
#else
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);
+ more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
+
+ /* Deal with !@#$% 64K limit: */
+ if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
+ more = wsize;
- /* Deal with !@#$% 64K limit: */
- if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
- more = s->w_size;
} 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)
/* 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 >= s->w_size+MAX_DIST(s)) {
-
- /* By the IN assertion, the window is not empty so we can't confuse
- * more == 0 with more == 64K on a 16 bit machine.
+ } 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.)
*/
- memcpy((char*)s->window, (char*)s->window+s->w_size,
- (unsigned)s->w_size);
- s->match_start -= s->w_size;
- s->strstart -= s->w_size; /* we now have strstart >= MAX_DIST */
-
- s->block_start -= (long) s->w_size;
-
- for (n = 0; n < s->hash_size; n++) {
- m = s->head[n];
- s->head[n] = (Pos)(m >= s->w_size ? m-s->w_size : NIL);
- }
- for (n = 0; n < s->w_size; n++) {
- m = s->prev[n];
- s->prev[n] = (Pos)(m >= s->w_size ? m-s->w_size : NIL);
- /* If n is not on any hash chain, prev[n] is garbage but
- * its value will never be used.
- */
- }
- more += s->w_size;
+ 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;
*/
Assert(more >= 2, "more < 2");
- n = read_buf(s->strm, (char*)s->window + s->strstart + s->lookahead,
- more);
- s->lookahead += n;
+ 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);
}
* IN assertion: strstart is set to the end of the current match.
*/
#define FLUSH_BLOCK_ONLY(s, eof) { \
- ct_flush_block(s, (s->block_start >= 0L ? \
- (char*)&s->window[(unsigned)s->block_start] : \
- (char*)Z_NULL), (long)s->strstart - s->block_start, (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 1; \
+ 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 true if
- * processing was terminated prematurely (no more input or output space).
- * This function does not perform lazy evaluationof matches and inserts
+ * 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 int deflate_fast(s, flush)
+local block_state deflate_fast(s, flush)
deflate_state *s;
int flush;
{
- IPos hash_head; /* head of the hash chain */
- int bflush; /* set if current block must be flushed */
-
- s->prev_length = MIN_MATCH-1;
+ 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
* string following the next match.
*/
if (s->lookahead < MIN_LOOKAHEAD) {
- fill_window(s);
- if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) return 1;
-
- if (s->lookahead == 0) break; /* flush the current block */
- }
+ 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:
*/
- INSERT_STRING(s, s->strstart, hash_head);
+ 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
* 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);
- }
+ if (s->strategy != Z_HUFFMAN_ONLY) {
+ s->match_length = longest_match (s, hash_head);
+ }
/* longest_match() sets match_start */
-
- if (s->match_length > s->lookahead) s->match_length = s->lookahead;
}
if (s->match_length >= MIN_MATCH) {
check_match(s, s->strstart, s->match_start, s->match_length);
- bflush = ct_tally(s, s->strstart - s->match_start,
- s->match_length - MIN_MATCH);
+ _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.
*/
- if (s->match_length <= s->max_insert_length) {
+#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. If lookahead < MIN_MATCH
- * these bytes are garbage, but it does not matter since
- * the next lookahead bytes will be emitted as literals.
+ * always MIN_MATCH bytes ahead.
*/
} while (--s->match_length != 0);
s->strstart++;
- } else {
+ } else
+#endif
+ {
s->strstart += s->match_length;
s->match_length = 0;
s->ins_h = s->window[s->strstart];
#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]));
- bflush = ct_tally (s, 0, 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 0; /* normal exit */
+ return flush == Z_FINISH ? finish_done : block_done;
}
/* ===========================================================================
* evaluation for matches: a match is finally adopted only if there is
* no better match at the next window position.
*/
-local int deflate_slow(s, flush)
+local block_state deflate_slow(s, flush)
deflate_state *s;
int flush;
{
- IPos hash_head; /* head of hash chain */
+ IPos hash_head = NIL; /* head of hash chain */
int bflush; /* set if current block must be flushed */
/* Process the input block. */
* string following the next match.
*/
if (s->lookahead < MIN_LOOKAHEAD) {
- fill_window(s);
- if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) return 1;
-
- if (s->lookahead == 0) break; /* flush the current block */
- }
+ 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:
*/
- INSERT_STRING(s, s->strstart, hash_head);
+ if (s->lookahead >= MIN_MATCH) {
+ INSERT_STRING(s, s->strstart, hash_head);
+ }
/* Find the longest match, discarding those <= prev_length.
*/
* 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);
- }
+ if (s->strategy != Z_HUFFMAN_ONLY) {
+ s->match_length = longest_match (s, hash_head);
+ }
/* longest_match() sets match_start */
- if (s->match_length > s->lookahead) s->match_length = s->lookahead;
if (s->match_length <= 5 && (s->strategy == Z_FILTERED ||
- (s->match_length == MIN_MATCH &&
- s->strstart - s->match_start > TOO_FAR))) {
+ (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.
* 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);
- bflush = ct_tally(s, s->strstart -1 - s->prev_match,
- s->prev_length - MIN_MATCH);
+ _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.
+ * 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 {
- s->strstart++;
- INSERT_STRING(s, s->strstart, hash_head);
- /* strstart never exceeds WSIZE-MAX_MATCH, so there are
- * always MIN_MATCH bytes ahead. If lookahead < MIN_MATCH
- * these bytes are garbage, but it does not matter since the
- * next lookahead bytes will always be emitted as literals.
- */
+ 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;
* is longer, truncate the previous match to a single literal.
*/
Tracevv((stderr,"%c", s->window[s->strstart-1]));
- if (ct_tally (s, 0, s->window[s->strstart-1])) {
- FLUSH_BLOCK_ONLY(s, 0);
+ _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 1;
+ 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->lookahead--;
}
}
- if (s->match_available) ct_tally (s, 0, s->window[s->strstart-1]);
-
+ 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 0;
+ return flush == Z_FINISH ? finish_done : block_done;
}
projects / zlib.git / blobdiff