/* 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
+ * Copyright (C) 1995-2022 Jean-loup Gailly and Mark Adler
+ * For conditions of distribution and use, see copyright notice in zlib.h
*/
/*
* REFERENCES
*
* Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
- * Available in ftp://ds.internic.net/rfc/rfc1951.txt
+ * Available in http://tools.ietf.org/html/rfc1951
*
* A description of the Rabin and Karp algorithm is given in the book
* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
#include "deflate.h"
const char deflate_copyright[] =
- " deflate 1.1.4 Copyright 1995-2002 Jean-loup Gailly ";
+ " deflate 1.2.12 Copyright 1995-2022 Jean-loup Gailly and Mark Adler ";
/*
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
typedef block_state (*compress_func) OF((deflate_state *s, int flush));
/* Compression function. Returns the block state after the call. */
+local int deflateStateCheck OF((z_streamp strm));
+local void slide_hash OF((deflate_state *s));
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));
+#ifndef FASTEST
local block_state deflate_slow OF((deflate_state *s, int flush));
+#endif
+local block_state deflate_rle OF((deflate_state *s, int flush));
+local block_state deflate_huff 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));
+local unsigned read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
#ifdef ASMV
+# pragma message("Assembler code may have bugs -- use at your own risk")
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
+#ifdef ZLIB_DEBUG
local void check_match OF((deflate_state *s, IPos start, IPos match,
int length));
#endif
#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
compress_func func;
} config;
+#ifdef FASTEST
+local const config configuration_table[2] = {
+/* good lazy nice chain */
+/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
+/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
+#else
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 */
+/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
/* 2 */ {4, 5, 16, 8, deflate_fast},
/* 3 */ {4, 6, 32, 32, deflate_fast},
/* 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 */
+/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
+#endif
/* 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 */
+/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
+#define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0))
/* ===========================================================================
* 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.
+ * IN assertion: all calls to UPDATE_HASH are made with consecutive input
+ * characters, so that a running hash key can be computed from the previous
+ * key instead of complete recalculation each time.
*/
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
* 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).
+ * IN assertion: all calls 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) \
#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], \
+ match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
s->head[s->ins_h] = (Pos)(str))
#endif
* 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));
+ do { \
+ s->head[s->hash_size-1] = NIL; \
+ zmemzero((Bytef *)s->head, \
+ (unsigned)(s->hash_size-1)*sizeof(*s->head)); \
+ } while (0)
+
+/* ===========================================================================
+ * Slide the hash table when sliding the window down (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.
+ */
+local void slide_hash(s)
+ deflate_state *s;
+{
+ unsigned n, m;
+ Posf *p;
+ uInt wsize = 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
+}
/* ========================================================================= */
int ZEXPORT deflateInit_(strm, level, version, stream_size)
int stream_size;
{
return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
- Z_DEFAULT_STRATEGY, version, stream_size);
+ 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)
+ version, stream_size)
z_streamp strm;
int level;
int method;
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.
- */
+ int wrap = 1;
+ static const char my_version[] = ZLIB_VERSION;
if (version == Z_NULL || version[0] != my_version[0] ||
stream_size != sizeof(z_stream)) {
- return Z_VERSION_ERROR;
+ 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->zalloc == (alloc_func)0) {
+#ifdef Z_SOLO
+ return Z_STREAM_ERROR;
+#else
+ strm->zalloc = zcalloc;
+ strm->opaque = (voidpf)0;
+#endif
}
- if (strm->zfree == Z_NULL) strm->zfree = zcfree;
+ if (strm->zfree == (free_func)0)
+#ifdef Z_SOLO
+ return Z_STREAM_ERROR;
+#else
+ strm->zfree = zcfree;
+#endif
- if (level == Z_DEFAULT_COMPRESSION) level = 6;
#ifdef FASTEST
- level = 1;
+ if (level != 0) level = 1;
+#else
+ if (level == Z_DEFAULT_COMPRESSION) level = 6;
#endif
- if (windowBits < 0) { /* undocumented feature: suppress zlib header */
- noheader = 1;
+ if (windowBits < 0) { /* suppress zlib wrapper */
+ wrap = 0;
windowBits = -windowBits;
}
+#ifdef GZIP
+ else if (windowBits > 15) {
+ wrap = 2; /* write gzip wrapper instead */
+ windowBits -= 16;
+ }
+#endif
if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
- windowBits < 9 || windowBits > 15 || level < 0 || level > 9 ||
- strategy < 0 || strategy > Z_HUFFMAN_ONLY) {
+ windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
+ strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) {
return Z_STREAM_ERROR;
}
+ if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
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->status = INIT_STATE; /* to pass state test in deflateReset() */
- s->noheader = noheader;
- s->w_bits = windowBits;
+ s->wrap = wrap;
+ s->gzhead = Z_NULL;
+ s->w_bits = (uInt)windowBits;
s->w_size = 1 << s->w_bits;
s->w_mask = s->w_size - 1;
- s->hash_bits = memLevel + 7;
+ s->hash_bits = (uInt)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->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
+ s->high_water = 0; /* nothing written to s->window yet */
+
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);
+ /* We overlay pending_buf and sym_buf. This works since the average size
+ * for length/distance pairs over any compressed block is assured to be 31
+ * bits or less.
+ *
+ * Analysis: The longest fixed codes are a length code of 8 bits plus 5
+ * extra bits, for lengths 131 to 257. The longest fixed distance codes are
+ * 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest
+ * possible fixed-codes length/distance pair is then 31 bits total.
+ *
+ * sym_buf starts one-fourth of the way into pending_buf. So there are
+ * three bytes in sym_buf for every four bytes in pending_buf. Each symbol
+ * in sym_buf is three bytes -- two for the distance and one for the
+ * literal/length. As each symbol is consumed, the pointer to the next
+ * sym_buf value to read moves forward three bytes. From that symbol, up to
+ * 31 bits are written to pending_buf. The closest the written pending_buf
+ * bits gets to the next sym_buf symbol to read is just before the last
+ * code is written. At that time, 31*(n-2) bits have been written, just
+ * after 24*(n-2) bits have been consumed from sym_buf. sym_buf starts at
+ * 8*n bits into pending_buf. (Note that the symbol buffer fills when n-1
+ * symbols are written.) The closest the writing gets to what is unread is
+ * then n+14 bits. Here n is lit_bufsize, which is 16384 by default, and
+ * can range from 128 to 32768.
+ *
+ * Therefore, at a minimum, there are 142 bits of space between what is
+ * written and what is read in the overlain buffers, so the symbols cannot
+ * be overwritten by the compressed data. That space is actually 139 bits,
+ * due to the three-bit fixed-code block header.
+ *
+ * That covers the case where either Z_FIXED is specified, forcing fixed
+ * codes, or when the use of fixed codes is chosen, because that choice
+ * results in a smaller compressed block than dynamic codes. That latter
+ * condition then assures that the above analysis also covers all dynamic
+ * blocks. A dynamic-code block will only be chosen to be emitted if it has
+ * fewer bits than a fixed-code block would for the same set of symbols.
+ * Therefore its average symbol length is assured to be less than 31. So
+ * the compressed data for a dynamic block also cannot overwrite the
+ * symbols from which it is being constructed.
+ */
+
+ s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, 4);
+ s->pending_buf_size = (ulg)s->lit_bufsize * 4;
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);
+ s->status = FINISH_STATE;
+ strm->msg = 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->sym_buf = s->pending_buf + s->lit_bufsize;
+ s->sym_end = (s->lit_bufsize - 1) * 3;
+ /* We avoid equality with lit_bufsize*3 because of wraparound at 64K
+ * on 16 bit machines and because stored blocks are restricted to
+ * 64K-1 bytes.
+ */
s->level = level;
s->strategy = strategy;
return deflateReset(strm);
}
+/* =========================================================================
+ * Check for a valid deflate stream state. Return 0 if ok, 1 if not.
+ */
+local int deflateStateCheck (strm)
+ z_streamp strm;
+{
+ deflate_state *s;
+ if (strm == Z_NULL ||
+ strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
+ return 1;
+ s = strm->state;
+ if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE &&
+#ifdef GZIP
+ s->status != GZIP_STATE &&
+#endif
+ s->status != EXTRA_STATE &&
+ s->status != NAME_STATE &&
+ s->status != COMMENT_STATE &&
+ s->status != HCRC_STATE &&
+ s->status != BUSY_STATE &&
+ s->status != FINISH_STATE))
+ return 1;
+ return 0;
+}
+
/* ========================================================================= */
int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
z_streamp strm;
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;
+ uInt str, n;
+ int wrap;
+ unsigned avail;
+ z_const unsigned char *next;
+ if (deflateStateCheck(strm) || dictionary == Z_NULL)
+ return Z_STREAM_ERROR;
s = strm->state;
- strm->adler = adler32(strm->adler, dictionary, dictLength);
+ wrap = s->wrap;
+ if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)
+ return Z_STREAM_ERROR;
- 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
+ /* when using zlib wrappers, compute Adler-32 for provided dictionary */
+ if (wrap == 1)
+ strm->adler = adler32(strm->adler, dictionary, dictLength);
+ s->wrap = 0; /* avoid computing Adler-32 in read_buf */
+
+ /* if dictionary would fill window, just replace the history */
+ if (dictLength >= s->w_size) {
+ if (wrap == 0) { /* already empty otherwise */
+ CLEAR_HASH(s);
+ s->strstart = 0;
+ s->block_start = 0L;
+ s->insert = 0;
+ }
+ dictionary += dictLength - s->w_size; /* use the tail */
+ dictLength = s->w_size;
}
- 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);
+ /* insert dictionary into window and hash */
+ avail = strm->avail_in;
+ next = strm->next_in;
+ strm->avail_in = dictLength;
+ strm->next_in = (z_const Bytef *)dictionary;
+ fill_window(s);
+ while (s->lookahead >= MIN_MATCH) {
+ str = s->strstart;
+ n = s->lookahead - (MIN_MATCH-1);
+ do {
+ UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
+#ifndef FASTEST
+ s->prev[str & s->w_mask] = s->head[s->ins_h];
+#endif
+ s->head[s->ins_h] = (Pos)str;
+ str++;
+ } while (--n);
+ s->strstart = str;
+ s->lookahead = MIN_MATCH-1;
+ fill_window(s);
}
- if (hash_head) hash_head = 0; /* to make compiler happy */
+ s->strstart += s->lookahead;
+ s->block_start = (long)s->strstart;
+ s->insert = s->lookahead;
+ s->lookahead = 0;
+ s->match_length = s->prev_length = MIN_MATCH-1;
+ s->match_available = 0;
+ strm->next_in = next;
+ strm->avail_in = avail;
+ s->wrap = wrap;
return Z_OK;
}
/* ========================================================================= */
-int ZEXPORT deflateReset (strm)
+int ZEXPORT deflateGetDictionary (strm, dictionary, dictLength)
z_streamp strm;
+ Bytef *dictionary;
+ uInt *dictLength;
{
deflate_state *s;
-
- if (strm == Z_NULL || strm->state == Z_NULL ||
- strm->zalloc == Z_NULL || strm->zfree == Z_NULL) return Z_STREAM_ERROR;
+ uInt len;
+
+ if (deflateStateCheck(strm))
+ return Z_STREAM_ERROR;
+ s = strm->state;
+ len = s->strstart + s->lookahead;
+ if (len > s->w_size)
+ len = s->w_size;
+ if (dictionary != Z_NULL && len)
+ zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len);
+ if (dictLength != Z_NULL)
+ *dictLength = len;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateResetKeep (strm)
+ z_streamp strm;
+{
+ deflate_state *s;
+
+ if (deflateStateCheck(strm)) {
+ 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); */
+ if (s->wrap < 0) {
+ s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
}
- s->status = s->noheader ? BUSY_STATE : INIT_STATE;
- strm->adler = 1;
- s->last_flush = Z_NO_FLUSH;
+ s->status =
+#ifdef GZIP
+ s->wrap == 2 ? GZIP_STATE :
+#endif
+ INIT_STATE;
+ strm->adler =
+#ifdef GZIP
+ s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
+#endif
+ adler32(0L, Z_NULL, 0);
+ s->last_flush = -2;
_tr_init(s);
- lm_init(s);
return Z_OK;
}
+/* ========================================================================= */
+int ZEXPORT deflateReset (strm)
+ z_streamp strm;
+{
+ int ret;
+
+ ret = deflateResetKeep(strm);
+ if (ret == Z_OK)
+ lm_init(strm->state);
+ return ret;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateSetHeader (strm, head)
+ z_streamp strm;
+ gz_headerp head;
+{
+ if (deflateStateCheck(strm) || strm->state->wrap != 2)
+ return Z_STREAM_ERROR;
+ strm->state->gzhead = head;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflatePending (strm, pending, bits)
+ unsigned *pending;
+ int *bits;
+ z_streamp strm;
+{
+ if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+ if (pending != Z_NULL)
+ *pending = strm->state->pending;
+ if (bits != Z_NULL)
+ *bits = strm->state->bi_valid;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflatePrime (strm, bits, value)
+ z_streamp strm;
+ int bits;
+ int value;
+{
+ deflate_state *s;
+ int put;
+
+ if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+ s = strm->state;
+ if (bits < 0 || bits > 16 ||
+ s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3))
+ return Z_BUF_ERROR;
+ do {
+ put = Buf_size - s->bi_valid;
+ if (put > bits)
+ put = bits;
+ s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
+ s->bi_valid += put;
+ _tr_flush_bits(s);
+ value >>= put;
+ bits -= put;
+ } while (bits);
+ return Z_OK;
+}
+
/* ========================================================================= */
int ZEXPORT deflateParams(strm, level, strategy)
z_streamp strm;
{
deflate_state *s;
compress_func func;
- int err = Z_OK;
- if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+ if (deflateStateCheck(strm)) 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;
+#ifdef FASTEST
+ if (level != 0) level = 1;
+#else
+ if (level == Z_DEFAULT_COMPRESSION) level = 6;
+#endif
+ if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
+ 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 ((strategy != s->strategy || func != configuration_table[level].func) &&
+ s->last_flush != -2) {
+ /* Flush the last buffer: */
+ int err = deflate(strm, Z_BLOCK);
+ if (err == Z_STREAM_ERROR)
+ return err;
+ if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead)
+ return Z_BUF_ERROR;
}
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;
+ if (s->level == 0 && s->matches != 0) {
+ if (s->matches == 1)
+ slide_hash(s);
+ else
+ CLEAR_HASH(s);
+ s->matches = 0;
+ }
+ 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;
+ return Z_OK;
+}
+
+/* ========================================================================= */
+int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
+ z_streamp strm;
+ int good_length;
+ int max_lazy;
+ int nice_length;
+ int max_chain;
+{
+ deflate_state *s;
+
+ if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
+ s = strm->state;
+ s->good_match = (uInt)good_length;
+ s->max_lazy_match = (uInt)max_lazy;
+ s->nice_match = nice_length;
+ s->max_chain_length = (uInt)max_chain;
+ return Z_OK;
+}
+
+/* =========================================================================
+ * 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. 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 complen, wraplen;
+
+ /* conservative upper bound for compressed data */
+ complen = sourceLen +
+ ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
+
+ /* if can't get parameters, return conservative bound plus zlib wrapper */
+ if (deflateStateCheck(strm))
+ return complen + 6;
+
+ /* compute wrapper length */
+ s = strm->state;
+ switch (s->wrap) {
+ case 0: /* raw deflate */
+ wraplen = 0;
+ break;
+ case 1: /* zlib wrapper */
+ wraplen = 6 + (s->strstart ? 4 : 0);
+ break;
+#ifdef GZIP
+ case 2: /* gzip wrapper */
+ wraplen = 18;
+ if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
+ Bytef *str;
+ if (s->gzhead->extra != Z_NULL)
+ wraplen += 2 + s->gzhead->extra_len;
+ str = s->gzhead->name;
+ if (str != Z_NULL)
+ do {
+ wraplen++;
+ } while (*str++);
+ str = s->gzhead->comment;
+ if (str != Z_NULL)
+ do {
+ wraplen++;
+ } while (*str++);
+ if (s->gzhead->hcrc)
+ wraplen += 2;
+ }
+ break;
+#endif
+ default: /* for compiler happiness */
+ wraplen = 6;
+ }
+
+ /* if not default parameters, return conservative bound */
+ if (s->w_bits != 15 || s->hash_bits != 8 + 7)
+ return complen + wraplen;
+
+ /* default settings: return tight bound for that case */
+ return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
+ (sourceLen >> 25) + 13 - 6 + wraplen;
}
/* =========================================================================
{
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()).
+ * Flush as much pending output as possible. All deflate() output, except for
+ * some deflate_stored() 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;
+ unsigned len;
+ deflate_state *s = strm->state;
+ _tr_flush_bits(s);
+ len = s->pending;
if (len > strm->avail_out) len = strm->avail_out;
if (len == 0) return;
- zmemcpy(strm->next_out, strm->state->pending_out, len);
+ zmemcpy(strm->next_out, s->pending_out, len);
strm->next_out += len;
- strm->state->pending_out += len;
+ s->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;
+ strm->avail_out -= len;
+ s->pending -= len;
+ if (s->pending == 0) {
+ s->pending_out = s->pending_buf;
}
}
+/* ===========================================================================
+ * Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1].
+ */
+#define HCRC_UPDATE(beg) \
+ do { \
+ if (s->gzhead->hcrc && s->pending > (beg)) \
+ strm->adler = crc32(strm->adler, s->pending_buf + (beg), \
+ s->pending - (beg)); \
+ } while (0)
+
/* ========================================================================= */
int ZEXPORT deflate (strm, flush)
z_streamp strm;
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) {
+ if (deflateStateCheck(strm) || flush > Z_BLOCK || 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)) {
+ (strm->avail_in != 0 && strm->next_in == Z_NULL) ||
+ (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:
+ /* 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;
- }
+ 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.
+ * returning Z_STREAM_END instead of Z_BUF_ERROR.
*/
- } else if (strm->avail_in == 0 && flush <= old_flush &&
- flush != Z_FINISH) {
+ } else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) &&
+ flush != Z_FINISH) {
ERR_RETURN(strm, Z_BUF_ERROR);
}
ERR_RETURN(strm, Z_BUF_ERROR);
}
+ /* Write the header */
+ if (s->status == INIT_STATE && s->wrap == 0)
+ s->status = BUSY_STATE;
+ if (s->status == INIT_STATE) {
+ /* zlib header */
+ uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
+ uInt level_flags;
+
+ if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
+ level_flags = 0;
+ else if (s->level < 6)
+ level_flags = 1;
+ else if (s->level == 6)
+ level_flags = 2;
+ else
+ level_flags = 3;
+ header |= (level_flags << 6);
+ if (s->strstart != 0) header |= PRESET_DICT;
+ header += 31 - (header % 31);
+
+ 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 = adler32(0L, Z_NULL, 0);
+ s->status = BUSY_STATE;
+
+ /* Compression must start with an empty pending buffer */
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ }
+#ifdef GZIP
+ if (s->status == GZIP_STATE) {
+ /* gzip header */
+ strm->adler = crc32(0L, Z_NULL, 0);
+ put_byte(s, 31);
+ put_byte(s, 139);
+ put_byte(s, 8);
+ if (s->gzhead == Z_NULL) {
+ put_byte(s, 0);
+ put_byte(s, 0);
+ put_byte(s, 0);
+ put_byte(s, 0);
+ put_byte(s, 0);
+ put_byte(s, s->level == 9 ? 2 :
+ (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
+ 4 : 0));
+ put_byte(s, OS_CODE);
+ s->status = BUSY_STATE;
+
+ /* Compression must start with an empty pending buffer */
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ }
+ else {
+ put_byte(s, (s->gzhead->text ? 1 : 0) +
+ (s->gzhead->hcrc ? 2 : 0) +
+ (s->gzhead->extra == Z_NULL ? 0 : 4) +
+ (s->gzhead->name == Z_NULL ? 0 : 8) +
+ (s->gzhead->comment == Z_NULL ? 0 : 16)
+ );
+ put_byte(s, (Byte)(s->gzhead->time & 0xff));
+ put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
+ put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
+ put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
+ put_byte(s, s->level == 9 ? 2 :
+ (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
+ 4 : 0));
+ put_byte(s, s->gzhead->os & 0xff);
+ if (s->gzhead->extra != Z_NULL) {
+ put_byte(s, s->gzhead->extra_len & 0xff);
+ put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
+ }
+ if (s->gzhead->hcrc)
+ strm->adler = crc32(strm->adler, s->pending_buf,
+ s->pending);
+ s->gzindex = 0;
+ s->status = EXTRA_STATE;
+ }
+ }
+ if (s->status == EXTRA_STATE) {
+ if (s->gzhead->extra != Z_NULL) {
+ ulg beg = s->pending; /* start of bytes to update crc */
+ uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
+ while (s->pending + left > s->pending_buf_size) {
+ uInt copy = s->pending_buf_size - s->pending;
+ zmemcpy(s->pending_buf + s->pending,
+ s->gzhead->extra + s->gzindex, copy);
+ s->pending = s->pending_buf_size;
+ HCRC_UPDATE(beg);
+ s->gzindex += copy;
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ beg = 0;
+ left -= copy;
+ }
+ zmemcpy(s->pending_buf + s->pending,
+ s->gzhead->extra + s->gzindex, left);
+ s->pending += left;
+ HCRC_UPDATE(beg);
+ s->gzindex = 0;
+ }
+ s->status = NAME_STATE;
+ }
+ if (s->status == NAME_STATE) {
+ if (s->gzhead->name != Z_NULL) {
+ ulg beg = s->pending; /* start of bytes to update crc */
+ int val;
+ do {
+ if (s->pending == s->pending_buf_size) {
+ HCRC_UPDATE(beg);
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ beg = 0;
+ }
+ val = s->gzhead->name[s->gzindex++];
+ put_byte(s, val);
+ } while (val != 0);
+ HCRC_UPDATE(beg);
+ s->gzindex = 0;
+ }
+ s->status = COMMENT_STATE;
+ }
+ if (s->status == COMMENT_STATE) {
+ if (s->gzhead->comment != Z_NULL) {
+ ulg beg = s->pending; /* start of bytes to update crc */
+ int val;
+ do {
+ if (s->pending == s->pending_buf_size) {
+ HCRC_UPDATE(beg);
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ beg = 0;
+ }
+ val = s->gzhead->comment[s->gzindex++];
+ put_byte(s, val);
+ } while (val != 0);
+ HCRC_UPDATE(beg);
+ }
+ s->status = HCRC_STATE;
+ }
+ if (s->status == HCRC_STATE) {
+ if (s->gzhead->hcrc) {
+ if (s->pending + 2 > s->pending_buf_size) {
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ }
+ put_byte(s, (Byte)(strm->adler & 0xff));
+ put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
+ strm->adler = crc32(0L, Z_NULL, 0);
+ }
+ s->status = BUSY_STATE;
+
+ /* Compression must start with an empty pending buffer */
+ flush_pending(strm);
+ if (s->pending != 0) {
+ s->last_flush = -1;
+ return Z_OK;
+ }
+ }
+#endif
+
/* 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);
+ bstate = s->level == 0 ? deflate_stored(s, flush) :
+ s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
+ s->strategy == Z_RLE ? deflate_rle(s, flush) :
+ (*(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 (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 */
+ } else if (flush != Z_BLOCK) { /* 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 */
+ if (s->lookahead == 0) {
+ s->strstart = 0;
+ s->block_start = 0L;
+ s->insert = 0;
+ }
}
}
flush_pending(strm);
- if (strm->avail_out == 0) {
- s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
- return Z_OK;
- }
+ 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));
+ if (s->wrap <= 0) return Z_STREAM_END;
+
+ /* Write the trailer */
+#ifdef GZIP
+ if (s->wrap == 2) {
+ put_byte(s, (Byte)(strm->adler & 0xff));
+ put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
+ put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
+ put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
+ put_byte(s, (Byte)(strm->total_in & 0xff));
+ put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
+ put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
+ put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
+ }
+ else
+#endif
+ {
+ 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! */
+ if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
return s->pending != 0 ? Z_OK : Z_STREAM_END;
}
{
int status;
- if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
+ if (deflateStateCheck(strm)) 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);
#else
deflate_state *ds;
deflate_state *ss;
- ushf *overlay;
- if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
+ if (deflateStateCheck(source) || dest == Z_NULL) {
return Z_STREAM_ERROR;
}
ss = source->state;
- *dest = *source;
+ zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
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;
+ zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));
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;
+ ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, 4);
if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
ds->pending_buf == Z_NULL) {
}
/* 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((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
+ zmemcpy((voidpf)ds->head, (voidpf)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->sym_buf = ds->pending_buf + 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
+#endif /* MAXSEG_64K */
}
/* ===========================================================================
* allocating a large strm->next_in buffer and copying from it.
* (See also flush_pending()).
*/
-local int read_buf(strm, buf, size)
+local unsigned read_buf(strm, buf, size)
z_streamp strm;
Bytef *buf;
unsigned size;
strm->avail_in -= len;
- if (!strm->state->noheader) {
- strm->adler = adler32(strm->adler, strm->next_in, len);
- }
zmemcpy(buf, strm->next_in, len);
+ if (strm->state->wrap == 1) {
+ strm->adler = adler32(strm->adler, buf, len);
+ }
+#ifdef GZIP
+ else if (strm->state->wrap == 2) {
+ strm->adler = crc32(strm->adler, buf, len);
+ }
+#endif
strm->next_in += len;
strm->total_in += len;
- return (int)len;
+ return len;
}
/* ===========================================================================
s->strstart = 0;
s->block_start = 0L;
s->lookahead = 0;
+ s->insert = 0;
s->match_length = s->prev_length = MIN_MATCH-1;
s->match_available = 0;
s->ins_h = 0;
+#ifndef FASTEST
#ifdef ASMV
match_init(); /* initialize the asm code */
#endif
+#endif
}
+#ifndef FASTEST
/* ===========================================================================
* 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,
/* 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 Bytef *match; /* matched string */
register int len; /* length of current match */
- int best_len = s->prev_length; /* best match length so far */
+ int best_len = (int)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;
/* 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;
+ if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead;
Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
match = s->window + cur_match;
/* Skip to next match if the match length cannot increase
- * or if the match length is less than 2:
+ * or if the match length is less than 2. Note that the checks below
+ * for insufficient lookahead only occur occasionally for performance
+ * reasons. Therefore uninitialized memory will be accessed, and
+ * conditional jumps will be made that depend on those values.
+ * However the length of the match is limited to the lookahead, so
+ * the output of deflate is not affected by the uninitialized values.
*/
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
/* This code assumes sizeof(unsigned short) == 2. Do not use
if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
return s->lookahead;
}
+#endif /* ASMV */
#else /* FASTEST */
+
/* ---------------------------------------------------------------------------
- * Optimized version for level == 1 only
+ * Optimized version for FASTEST only
*/
local uInt longest_match(s, cur_match)
deflate_state *s;
*/
do {
} while (*++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- *++scan == *++match && *++scan == *++match &&
- scan < strend);
+ *++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");
if (len < MIN_MATCH) return MIN_MATCH - 1;
s->match_start = cur_match;
- return len <= s->lookahead ? len : s->lookahead;
+ return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
}
+
#endif /* FASTEST */
-#endif /* ASMV */
-#ifdef DEBUG
+#ifdef ZLIB_DEBUG
+
+#define EQUAL 0
+/* result of memcmp for equal strings */
+
/* ===========================================================================
* Check that the match at match_start 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);
+ start, match, length);
do {
- fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
- } while (--length != 0);
+ fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
+ } while (--length != 0);
z_error("invalid match");
}
if (z_verbose > 1) {
}
#else
# define check_match(s, start, match, length)
-#endif
+#endif /* ZLIB_DEBUG */
/* ===========================================================================
* Fill the window when the lookahead becomes insufficient.
local void fill_window(s)
deflate_state *s;
{
- register unsigned n, m;
- register Posf *p;
+ unsigned n;
unsigned more; /* Amount of free space at the end of the window. */
uInt wsize = s->w_size;
+ Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
+
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;
+ if (sizeof(int) <= 2) {
+ 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--;
+ } else if (more == (unsigned)(-1)) {
+ /* Very unlikely, but possible on 16 bit machine if
+ * strstart == 0 && lookahead == 1 (input done a 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)) {
+ if (s->strstart >= wsize+MAX_DIST(s)) {
- zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
+ zmemcpy(s->window, s->window+wsize, (unsigned)wsize - more);
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
+ if (s->insert > s->strstart)
+ s->insert = s->strstart;
+ slide_hash(s);
more += wsize;
}
- if (s->strm->avail_in == 0) return;
+ if (s->strm->avail_in == 0) break;
/* If there was no sliding:
* strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
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 (s->lookahead + s->insert >= MIN_MATCH) {
+ uInt str = s->strstart - s->insert;
+ s->ins_h = s->window[str];
+ UPDATE_HASH(s, s->ins_h, s->window[str + 1]);
#if MIN_MATCH != 3
Call UPDATE_HASH() MIN_MATCH-3 more times
#endif
+ while (s->insert) {
+ UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
+#ifndef FASTEST
+ s->prev[str & s->w_mask] = s->head[s->ins_h];
+#endif
+ s->head[s->ins_h] = (Pos)str;
+ str++;
+ s->insert--;
+ if (s->lookahead + s->insert < MIN_MATCH)
+ break;
+ }
}
/* 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);
+
+ /* If the WIN_INIT bytes after the end of the current data have never been
+ * written, then zero those bytes in order to avoid memory check reports of
+ * the use of uninitialized (or uninitialised as Julian writes) bytes by
+ * the longest match routines. Update the high water mark for the next
+ * time through here. WIN_INIT is set to MAX_MATCH since the longest match
+ * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
+ */
+ if (s->high_water < s->window_size) {
+ ulg curr = s->strstart + (ulg)(s->lookahead);
+ ulg init;
+
+ if (s->high_water < curr) {
+ /* Previous high water mark below current data -- zero WIN_INIT
+ * bytes or up to end of window, whichever is less.
+ */
+ init = s->window_size - curr;
+ if (init > WIN_INIT)
+ init = WIN_INIT;
+ zmemzero(s->window + curr, (unsigned)init);
+ s->high_water = curr + init;
+ }
+ else if (s->high_water < (ulg)curr + WIN_INIT) {
+ /* High water mark at or above current data, but below current data
+ * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
+ * to end of window, whichever is less.
+ */
+ init = (ulg)curr + WIN_INIT - s->high_water;
+ if (init > s->window_size - s->high_water)
+ init = s->window_size - s->high_water;
+ zmemzero(s->window + s->high_water, (unsigned)init);
+ s->high_water += init;
+ }
+ }
+
+ Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
+ "not enough room for search");
}
/* ===========================================================================
* 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) { \
+#define FLUSH_BLOCK_ONLY(s, last) { \
_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)); \
+ (ulg)((long)s->strstart - s->block_start), \
+ (last)); \
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; \
+#define FLUSH_BLOCK(s, last) { \
+ FLUSH_BLOCK_ONLY(s, last); \
+ if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
}
+/* Maximum stored block length in deflate format (not including header). */
+#define MAX_STORED 65535
+
+/* Minimum of a and b. */
+#define MIN(a, b) ((a) > (b) ? (b) : (a))
+
/* ===========================================================================
* 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.
+ *
+ * In case deflateParams() is used to later switch to a non-zero compression
+ * level, s->matches (otherwise unused when storing) keeps track of the number
+ * of hash table slides to perform. If s->matches is 1, then one hash table
+ * slide will be done when switching. If s->matches is 2, the maximum value
+ * allowed here, then the hash table will be cleared, since two or more slides
+ * is the same as a clear.
+ *
+ * deflate_stored() is written to minimize the number of times an input byte is
+ * copied. It is most efficient with large input and output buffers, which
+ * maximizes the opportunites to have a single copy from next_in to next_out.
*/
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:
+ /* Smallest worthy block size when not flushing or finishing. By default
+ * this is 32K. This can be as small as 507 bytes for memLevel == 1. For
+ * large input and output buffers, the stored block size will be larger.
*/
- 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;
- }
+ unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size);
- /* Copy as much as possible from input to output: */
- for (;;) {
- /* Fill the window as much as possible: */
- if (s->lookahead <= 1) {
+ /* Copy as many min_block or larger stored blocks directly to next_out as
+ * possible. If flushing, copy the remaining available input to next_out as
+ * stored blocks, if there is enough space.
+ */
+ unsigned len, left, have, last = 0;
+ unsigned used = s->strm->avail_in;
+ do {
+ /* Set len to the maximum size block that we can copy directly with the
+ * available input data and output space. Set left to how much of that
+ * would be copied from what's left in the window.
+ */
+ len = MAX_STORED; /* maximum deflate stored block length */
+ have = (s->bi_valid + 42) >> 3; /* number of header bytes */
+ if (s->strm->avail_out < have) /* need room for header */
+ break;
+ /* maximum stored block length that will fit in avail_out: */
+ have = s->strm->avail_out - have;
+ left = s->strstart - s->block_start; /* bytes left in window */
+ if (len > (ulg)left + s->strm->avail_in)
+ len = left + s->strm->avail_in; /* limit len to the input */
+ if (len > have)
+ len = have; /* limit len to the output */
+
+ /* If the stored block would be less than min_block in length, or if
+ * unable to copy all of the available input when flushing, then try
+ * copying to the window and the pending buffer instead. Also don't
+ * write an empty block when flushing -- deflate() does that.
+ */
+ if (len < min_block && ((len == 0 && flush != Z_FINISH) ||
+ flush == Z_NO_FLUSH ||
+ len != left + s->strm->avail_in))
+ break;
- Assert(s->strstart < s->w_size+MAX_DIST(s) ||
- s->block_start >= (long)s->w_size, "slide too late");
+ /* Make a dummy stored block in pending to get the header bytes,
+ * including any pending bits. This also updates the debugging counts.
+ */
+ last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0;
+ _tr_stored_block(s, (char *)0, 0L, last);
+
+ /* Replace the lengths in the dummy stored block with len. */
+ s->pending_buf[s->pending - 4] = len;
+ s->pending_buf[s->pending - 3] = len >> 8;
+ s->pending_buf[s->pending - 2] = ~len;
+ s->pending_buf[s->pending - 1] = ~len >> 8;
+
+ /* Write the stored block header bytes. */
+ flush_pending(s->strm);
+
+#ifdef ZLIB_DEBUG
+ /* Update debugging counts for the data about to be copied. */
+ s->compressed_len += len << 3;
+ s->bits_sent += len << 3;
+#endif
- fill_window(s);
- if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
+ /* Copy uncompressed bytes from the window to next_out. */
+ if (left) {
+ if (left > len)
+ left = len;
+ zmemcpy(s->strm->next_out, s->window + s->block_start, left);
+ s->strm->next_out += left;
+ s->strm->avail_out -= left;
+ s->strm->total_out += left;
+ s->block_start += left;
+ len -= left;
+ }
- if (s->lookahead == 0) break; /* flush the current block */
+ /* Copy uncompressed bytes directly from next_in to next_out, updating
+ * the check value.
+ */
+ if (len) {
+ read_buf(s->strm, s->strm->next_out, len);
+ s->strm->next_out += len;
+ s->strm->avail_out -= len;
+ s->strm->total_out += len;
}
- 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:
+ } while (last == 0);
+
+ /* Update the sliding window with the last s->w_size bytes of the copied
+ * data, or append all of the copied data to the existing window if less
+ * than s->w_size bytes were copied. Also update the number of bytes to
+ * insert in the hash tables, in the event that deflateParams() switches to
+ * a non-zero compression level.
+ */
+ used -= s->strm->avail_in; /* number of input bytes directly copied */
+ if (used) {
+ /* If any input was used, then no unused input remains in the window,
+ * therefore s->block_start == s->strstart.
*/
- if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
- FLUSH_BLOCK(s, 0);
- }
+ if (used >= s->w_size) { /* supplant the previous history */
+ s->matches = 2; /* clear hash */
+ zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
+ s->strstart = s->w_size;
+ s->insert = s->strstart;
+ }
+ else {
+ if (s->window_size - s->strstart <= used) {
+ /* Slide the window down. */
+ s->strstart -= s->w_size;
+ zmemcpy(s->window, s->window + s->w_size, s->strstart);
+ if (s->matches < 2)
+ s->matches++; /* add a pending slide_hash() */
+ if (s->insert > s->strstart)
+ s->insert = s->strstart;
+ }
+ zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
+ s->strstart += used;
+ s->insert += MIN(used, s->w_size - s->insert);
+ }
+ s->block_start = s->strstart;
+ }
+ if (s->high_water < s->strstart)
+ s->high_water = s->strstart;
+
+ /* If the last block was written to next_out, then done. */
+ if (last)
+ return finish_done;
+
+ /* If flushing and all input has been consumed, then done. */
+ if (flush != Z_NO_FLUSH && flush != Z_FINISH &&
+ s->strm->avail_in == 0 && (long)s->strstart == s->block_start)
+ return block_done;
+
+ /* Fill the window with any remaining input. */
+ have = s->window_size - s->strstart;
+ if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
+ /* Slide the window down. */
+ s->block_start -= s->w_size;
+ s->strstart -= s->w_size;
+ zmemcpy(s->window, s->window + s->w_size, s->strstart);
+ if (s->matches < 2)
+ s->matches++; /* add a pending slide_hash() */
+ have += s->w_size; /* more space now */
+ if (s->insert > s->strstart)
+ s->insert = s->strstart;
}
- FLUSH_BLOCK(s, flush == Z_FINISH);
- return flush == Z_FINISH ? finish_done : block_done;
+ if (have > s->strm->avail_in)
+ have = s->strm->avail_in;
+ if (have) {
+ read_buf(s->strm, s->window + s->strstart, have);
+ s->strstart += have;
+ s->insert += MIN(have, s->w_size - s->insert);
+ }
+ if (s->high_water < s->strstart)
+ s->high_water = s->strstart;
+
+ /* There was not enough avail_out to write a complete worthy or flushed
+ * stored block to next_out. Write a stored block to pending instead, if we
+ * have enough input for a worthy block, or if flushing and there is enough
+ * room for the remaining input as a stored block in the pending buffer.
+ */
+ have = (s->bi_valid + 42) >> 3; /* number of header bytes */
+ /* maximum stored block length that will fit in pending: */
+ have = MIN(s->pending_buf_size - have, MAX_STORED);
+ min_block = MIN(have, s->w_size);
+ left = s->strstart - s->block_start;
+ if (left >= min_block ||
+ ((left || flush == Z_FINISH) && flush != Z_NO_FLUSH &&
+ s->strm->avail_in == 0 && left <= have)) {
+ len = MIN(left, have);
+ last = flush == Z_FINISH && s->strm->avail_in == 0 &&
+ len == left ? 1 : 0;
+ _tr_stored_block(s, (charf *)s->window + s->block_start, len, last);
+ s->block_start += len;
+ flush_pending(s->strm);
+ }
+
+ /* We've done all we can with the available input and output. */
+ return last ? finish_started : need_more;
}
/* ===========================================================================
deflate_state *s;
int flush;
{
- IPos hash_head = NIL; /* head of the hash chain */
+ IPos hash_head; /* head of the hash chain */
int bflush; /* set if current block must be flushed */
for (;;) {
if (s->lookahead < MIN_LOOKAHEAD) {
fill_window(s);
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
- return need_more;
- }
+ 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:
*/
+ hash_head = NIL;
if (s->lookahead >= MIN_MATCH) {
INSERT_STRING(s, s->strstart, hash_head);
}
* 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);
- }
+ s->match_length = longest_match (s, hash_head);
/* longest_match() sets match_start */
}
if (s->match_length >= MIN_MATCH) {
#ifndef FASTEST
if (s->match_length <= s->max_insert_length &&
s->lookahead >= MIN_MATCH) {
- s->match_length--; /* string at strstart already in hash table */
+ s->match_length--; /* string at strstart already in table */
do {
s->strstart++;
INSERT_STRING(s, s->strstart, hash_head);
* always MIN_MATCH bytes ahead.
*/
} while (--s->match_length != 0);
- s->strstart++;
+ s->strstart++;
} else
#endif
- {
+ {
s->strstart += s->match_length;
s->match_length = 0;
s->ins_h = s->window[s->strstart];
Tracevv((stderr,"%c", s->window[s->strstart]));
_tr_tally_lit (s, s->window[s->strstart], bflush);
s->lookahead--;
- s->strstart++;
+ s->strstart++;
}
if (bflush) FLUSH_BLOCK(s, 0);
}
- FLUSH_BLOCK(s, flush == Z_FINISH);
- return flush == Z_FINISH ? finish_done : block_done;
+ s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
+ if (flush == Z_FINISH) {
+ FLUSH_BLOCK(s, 1);
+ return finish_done;
+ }
+ if (s->sym_next)
+ FLUSH_BLOCK(s, 0);
+ return block_done;
}
+#ifndef FASTEST
/* ===========================================================================
* Same as above, but achieves better compression. We use a lazy
* evaluation for matches: a match is finally adopted only if there is
deflate_state *s;
int flush;
{
- IPos hash_head = NIL; /* head of hash chain */
+ IPos hash_head; /* head of hash chain */
int bflush; /* set if current block must be flushed */
/* Process the input block. */
if (s->lookahead < MIN_LOOKAHEAD) {
fill_window(s);
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
- return need_more;
- }
+ 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:
*/
+ hash_head = NIL;
if (s->lookahead >= MIN_MATCH) {
INSERT_STRING(s, s->strstart, hash_head);
}
* 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);
- }
+ 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 (s->match_length <= 5 && (s->strategy == Z_FILTERED
+#if TOO_FAR <= 32767
+ || (s->match_length == MIN_MATCH &&
+ s->strstart - s->match_start > TOO_FAR)
+#endif
+ )) {
/* If prev_match is also MIN_MATCH, match_start is garbage
* but we will ignore the current match anyway.
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);
+ 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
* 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) {
+ _tr_tally_lit(s, s->window[s->strstart-1], bflush);
+ if (bflush) {
FLUSH_BLOCK_ONLY(s, 0);
}
s->strstart++;
_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;
+ s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
+ if (flush == Z_FINISH) {
+ FLUSH_BLOCK(s, 1);
+ return finish_done;
+ }
+ if (s->sym_next)
+ FLUSH_BLOCK(s, 0);
+ return block_done;
+}
+#endif /* FASTEST */
+
+/* ===========================================================================
+ * For Z_RLE, simply look for runs of bytes, generate matches only of distance
+ * one. Do not maintain a hash table. (It will be regenerated if this run of
+ * deflate switches away from Z_RLE.)
+ */
+local block_state deflate_rle(s, flush)
+ deflate_state *s;
+ int flush;
+{
+ int bflush; /* set if current block must be flushed */
+ uInt prev; /* byte at distance one to match */
+ Bytef *scan, *strend; /* scan goes up to strend for length of run */
+
+ for (;;) {
+ /* Make sure that we always have enough lookahead, except
+ * at the end of the input file. We need MAX_MATCH bytes
+ * for the longest run, plus one for the unrolled loop.
+ */
+ if (s->lookahead <= MAX_MATCH) {
+ fill_window(s);
+ if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
+ return need_more;
+ }
+ if (s->lookahead == 0) break; /* flush the current block */
+ }
+
+ /* See how many times the previous byte repeats */
+ s->match_length = 0;
+ if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
+ scan = s->window + s->strstart - 1;
+ prev = *scan;
+ if (prev == *++scan && prev == *++scan && prev == *++scan) {
+ strend = s->window + s->strstart + MAX_MATCH;
+ do {
+ } while (prev == *++scan && prev == *++scan &&
+ prev == *++scan && prev == *++scan &&
+ prev == *++scan && prev == *++scan &&
+ prev == *++scan && prev == *++scan &&
+ scan < strend);
+ s->match_length = MAX_MATCH - (uInt)(strend - scan);
+ if (s->match_length > s->lookahead)
+ s->match_length = s->lookahead;
+ }
+ Assert(scan <= s->window+(uInt)(s->window_size-1), "wild scan");
+ }
+
+ /* Emit match if have run of MIN_MATCH or longer, else emit literal */
+ if (s->match_length >= MIN_MATCH) {
+ check_match(s, s->strstart, s->strstart - 1, s->match_length);
+
+ _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
+
+ s->lookahead -= s->match_length;
+ s->strstart += s->match_length;
+ s->match_length = 0;
+ } 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);
+ }
+ s->insert = 0;
+ if (flush == Z_FINISH) {
+ FLUSH_BLOCK(s, 1);
+ return finish_done;
+ }
+ if (s->sym_next)
+ FLUSH_BLOCK(s, 0);
+ return block_done;
+}
+
+/* ===========================================================================
+ * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
+ * (It will be regenerated if this run of deflate switches away from Huffman.)
+ */
+local block_state deflate_huff(s, flush)
+ deflate_state *s;
+ int flush;
+{
+ int bflush; /* set if current block must be flushed */
+
+ for (;;) {
+ /* Make sure that we have a literal to write. */
+ if (s->lookahead == 0) {
+ fill_window(s);
+ if (s->lookahead == 0) {
+ if (flush == Z_NO_FLUSH)
+ return need_more;
+ break; /* flush the current block */
+ }
+ }
+
+ /* Output a literal byte */
+ s->match_length = 0;
+ 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);
+ }
+ s->insert = 0;
+ if (flush == Z_FINISH) {
+ FLUSH_BLOCK(s, 1);
+ return finish_done;
+ }
+ if (s->sym_next)
+ FLUSH_BLOCK(s, 0);
+ return block_done;
}
projects / zlib.git / blobdiff