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Copy pathdeflate.c
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1736 lines (1548 loc) · 62.7 KB
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/* deflate.c -- compress data using the deflation algorithm
* Copyright (C) 1995-2005 Jean-loup Gailly.
* For conditions of distribution and use, see copyright notice in zlib.h
*/
/*
* ALGORITHM
*
* The "deflation" process depends on being able to identify portions
* of the input text which are identical to earlier input (within a
* sliding window trailing behind the input currently being processed).
*
* The most straightforward technique turns out to be the fastest for
* most input files: try all possible matches and select the longest.
* The key feature of this algorithm is that insertions into the string
* dictionary are very simple and thus fast, and deletions are avoided
* completely. Insertions are performed at each input character, whereas
* string matches are performed only when the previous match ends. So it
* is preferable to spend more time in matches to allow very fast string
* insertions and avoid deletions. The matching algorithm for small
* strings is inspired from that of Rabin & Karp. A brute force approach
* is used to find longer strings when a small match has been found.
* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
* (by Leonid Broukhis).
* A previous version of this file used a more sophisticated algorithm
* (by Fiala and Greene) which is guaranteed to run in linear amortized
* time, but has a larger average cost, uses more memory and is patented.
* However the F&G algorithm may be faster for some highly redundant
* files if the parameter max_chain_length (described below) is too large.
*
* ACKNOWLEDGEMENTS
*
* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
* I found it in 'freeze' written by Leonid Broukhis.
* Thanks to many people for bug reports and testing.
*
* REFERENCES
*
* Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
* Available in http://www.ietf.org/rfc/rfc1951.txt
*
* A description of the Rabin and Karp algorithm is given in the book
* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
*
* Fiala,E.R., and Greene,D.H.
* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
*
*/
/* @(#) $Id$ */
#include "deflate.h"
const char deflate_copyright[] =
" deflate 1.2.3 Copyright 1995-2005 Jean-loup Gailly ";
/*
If you use the zlib library in a product, an acknowledgment is welcome
in the documentation of your product. If for some reason you cannot
include such an acknowledgment, I would appreciate that you keep this
copyright string in the executable of your product.
*/
/* ===========================================================================
* Function prototypes.
*/
typedef enum {
need_more, /* block not completed, need more input or more output */
block_done, /* block flush performed */
finish_started, /* finish started, need only more output at next deflate */
finish_done /* finish done, accept no more input or output */
} block_state;
typedef block_state (*compress_func) OF((deflate_state *s, int flush));
/* Compression function. Returns the block state after the call. */
local void fill_window OF((deflate_state *s));
local block_state deflate_stored OF((deflate_state *s, int flush));
local block_state deflate_fast OF((deflate_state *s, int flush));
#ifndef FASTEST
local block_state deflate_slow OF((deflate_state *s, int flush));
#endif
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));
#ifndef FASTEST
#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
#endif
local uInt longest_match_fast OF((deflate_state *s, IPos cur_match));
#ifdef DEBUG
local void check_match OF((deflate_state *s, IPos start, IPos match,
int length));
#endif
/* ===========================================================================
* Local data
*/
#define NIL 0
/* Tail of hash chains */
#ifndef TOO_FAR
# define TOO_FAR 4096
#endif
/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
#define MIN_LOOKAHEAD (MAX_MATCH+MIN_MATCH+1)
/* Minimum amount of lookahead, except at the end of the input file.
* See deflate.c for comments about the MIN_MATCH+1.
*/
/* Values for max_lazy_match, good_match and max_chain_length, depending on
* the desired pack level (0..9). The values given below have been tuned to
* exclude worst case performance for pathological files. Better values may be
* found for specific files.
*/
typedef struct config_s {
ush good_length; /* reduce lazy search above this match length */
ush max_lazy; /* do not perform lazy search above this match length */
ush nice_length; /* quit search above this match length */
ush max_chain;
compress_func func;
} config;
#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}, /* max 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}}; /* 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 */
#ifndef NO_DUMMY_DECL
struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
#endif
/* ===========================================================================
* Update a hash value with the given input byte
* IN assertion: all calls to to UPDATE_HASH are made with consecutive
* input characters, so that a running hash key can be computed from the
* previous key instead of complete recalculation each time.
*/
#define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
/* ===========================================================================
* Insert string str in the dictionary and set match_head to the previous head
* of the hash chain (the most recent string with same hash key). Return
* the previous length of the hash chain.
* If this file is compiled with -DFASTEST, the compression level is forced
* to 1, and no hash chains are maintained.
* IN assertion: all calls to to INSERT_STRING are made with consecutive
* input characters and the first MIN_MATCH bytes of str are valid
* (except for the last MIN_MATCH-1 bytes of the input file).
*/
#ifdef FASTEST
#define INSERT_STRING(s, str, match_head) \
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
match_head = s->head[s->ins_h], \
s->head[s->ins_h] = (Pos)(str))
#else
#define INSERT_STRING(s, str, match_head) \
(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
s->head[s->ins_h] = (Pos)(str))
#endif
/* ===========================================================================
* Initialize the hash table (avoiding 64K overflow for 16 bit systems).
* prev[] will be initialized on the fly.
*/
#define CLEAR_HASH(s) \
s->head[s->hash_size-1] = NIL; \
zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
/* ========================================================================= */
int ZEXPORT deflateInit_(strm, level, version, stream_size)
z_streamp strm;
int level;
const char *version;
int stream_size;
{
return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
Z_DEFAULT_STRATEGY, version, stream_size);
/* To do: ignore strm->next_in if we use it as window */
}
/* ========================================================================= */
int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
version, stream_size)
z_streamp strm;
int level;
int method;
int windowBits;
int memLevel;
int strategy;
const char *version;
int stream_size;
{
deflate_state *s;
int wrap = 1;
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 == (alloc_func)0) {
strm->zalloc = zcalloc;
strm->opaque = (voidpf)0;
}
if (strm->zfree == (free_func)0) strm->zfree = zcfree;
#ifdef FASTEST
if (level != 0) level = 1;
#else
if (level == Z_DEFAULT_COMPRESSION) level = 6;
#endif
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 < 8 || windowBits > 15 || level < 0 || level > 9 ||
strategy < 0 || strategy > Z_FIXED) {
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->wrap = wrap;
s->gzhead = Z_NULL;
s->w_bits = windowBits;
s->w_size = 1 << s->w_bits;
s->w_mask = s->w_size - 1;
s->hash_bits = memLevel + 7;
s->hash_size = 1 << s->hash_bits;
s->hash_mask = s->hash_size - 1;
s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
s->pending_buf = (uchf *) overlay;
s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
s->pending_buf == Z_NULL) {
s->status = FINISH_STATE;
strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
deflateEnd (strm);
return Z_MEM_ERROR;
}
s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
s->level = level;
s->strategy = strategy;
s->method = (Byte)method;
return deflateReset(strm);
}
/* ========================================================================= */
int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
z_streamp strm;
const Bytef *dictionary;
uInt dictLength;
{
deflate_state *s;
uInt length = dictLength;
uInt n;
IPos hash_head = 0;
if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
strm->state->wrap == 2 ||
(strm->state->wrap == 1 && strm->state->status != INIT_STATE))
return Z_STREAM_ERROR;
s = strm->state;
if (s->wrap)
strm->adler = adler32(strm->adler, dictionary, dictLength);
if (length < MIN_MATCH) return Z_OK;
if (length > MAX_DIST(s)) {
length = MAX_DIST(s);
dictionary += dictLength - length; /* use the tail of the dictionary */
}
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 == (alloc_func)0 || strm->zfree == (free_func)0) {
return Z_STREAM_ERROR;
}
strm->total_in = strm->total_out = 0;
strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
strm->data_type = Z_UNKNOWN;
s = (deflate_state *)strm->state;
s->pending = 0;
s->pending_out = s->pending_buf;
if (s->wrap < 0) {
s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
}
s->status = s->wrap ? INIT_STATE : BUSY_STATE;
strm->adler =
#ifdef GZIP
s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
#endif
adler32(0L, Z_NULL, 0);
s->last_flush = Z_NO_FLUSH;
_tr_init(s);
lm_init(s);
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT deflateSetHeader (strm, head)
z_streamp strm;
gz_headerp head;
{
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
if (strm->state->wrap != 2) return Z_STREAM_ERROR;
strm->state->gzhead = head;
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT deflatePrime (strm, bits, value)
z_streamp strm;
int bits;
int value;
{
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
strm->state->bi_valid = bits;
strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
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;
#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 (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;
}
/* ========================================================================= */
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 (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
s = strm->state;
s->good_match = good_length;
s->max_lazy_match = max_lazy;
s->nice_match = nice_length;
s->max_chain_length = 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, as well as wrap.
* 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
* pending_buf.
*/
local void putShortMSB (s, b)
deflate_state *s;
uInt b;
{
put_byte(s, (Byte)(b >> 8));
put_byte(s, (Byte)(b & 0xff));
}
/* =========================================================================
* Flush as much pending output as possible. All deflate() output goes
* through this function so some applications may wish to modify it
* to avoid allocating a large strm->next_out buffer and copying into it.
* (See also read_buf()).
*/
local void flush_pending(strm)
z_streamp strm;
{
unsigned len = strm->state->pending;
if (len > strm->avail_out) len = strm->avail_out;
if (len == 0) return;
zmemcpy(strm->next_out, strm->state->pending_out, len);
strm->next_out += len;
strm->state->pending_out += len;
strm->total_out += len;
strm->avail_out -= len;
strm->state->pending -= len;
if (strm->state->pending == 0) {
strm->state->pending_out = strm->state->pending_buf;
}
}
/* ========================================================================= */
int ZEXPORT deflate (strm, flush)
z_streamp strm;
int flush;
{
int old_flush; /* value of flush param for previous deflate call */
deflate_state *s;
if (strm == Z_NULL || strm->state == Z_NULL ||
flush > Z_FINISH || flush < 0) {
return Z_STREAM_ERROR;
}
s = strm->state;
if (strm->next_out == Z_NULL ||
(strm->next_in == Z_NULL && strm->avail_in != 0) ||
(s->status == FINISH_STATE && flush != Z_FINISH)) {
ERR_RETURN(strm, Z_STREAM_ERROR);
}
if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
s->strm = strm; /* just in case */
old_flush = s->last_flush;
s->last_flush = flush;
/* Write the header */
if (s->status == INIT_STATE) {
#ifdef GZIP
if (s->wrap == 2) {
strm->adler = crc32(0L, Z_NULL, 0);
put_byte(s, 31);
put_byte(s, 139);
put_byte(s, 8);
if (s->gzhead == 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;
}
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 != 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;
}
}
else
#endif
{
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);
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 = adler32(0L, Z_NULL, 0);
}
}
#ifdef GZIP
if (s->status == EXTRA_STATE) {
if (s->gzhead->extra != NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
if (s->pending == s->pending_buf_size) {
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
flush_pending(strm);
beg = s->pending;
if (s->pending == s->pending_buf_size)
break;
}
put_byte(s, s->gzhead->extra[s->gzindex]);
s->gzindex++;
}
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
if (s->gzindex == s->gzhead->extra_len) {
s->gzindex = 0;
s->status = NAME_STATE;
}
}
else
s->status = NAME_STATE;
}
if (s->status == NAME_STATE) {
if (s->gzhead->name != NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
int val;
do {
if (s->pending == s->pending_buf_size) {
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
flush_pending(strm);
beg = s->pending;
if (s->pending == s->pending_buf_size) {
val = 1;
break;
}
}
val = s->gzhead->name[s->gzindex++];
put_byte(s, val);
} while (val != 0);
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
if (val == 0) {
s->gzindex = 0;
s->status = COMMENT_STATE;
}
}
else
s->status = COMMENT_STATE;
}
if (s->status == COMMENT_STATE) {
if (s->gzhead->comment != NULL) {
uInt beg = s->pending; /* start of bytes to update crc */
int val;
do {
if (s->pending == s->pending_buf_size) {
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
flush_pending(strm);
beg = s->pending;
if (s->pending == s->pending_buf_size) {
val = 1;
break;
}
}
val = s->gzhead->comment[s->gzindex++];
put_byte(s, val);
} while (val != 0);
if (s->gzhead->hcrc && s->pending > beg)
strm->adler = crc32(strm->adler, s->pending_buf + beg,
s->pending - beg);
if (val == 0)
s->status = HCRC_STATE;
}
else
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 + 2 <= s->pending_buf_size) {
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;
}
}
else
s->status = BUSY_STATE;
}
#endif
/* Flush as much pending output as possible */
if (s->pending != 0) {
flush_pending(strm);
if (strm->avail_out == 0) {
/* Since avail_out is 0, deflate will be called again with
* more output space, but possibly with both pending and
* avail_in equal to zero. There won't be anything to do,
* but this is not an error situation so make sure we
* return OK instead of BUF_ERROR at next call of deflate:
*/
s->last_flush = -1;
return Z_OK;
}
/* Make sure there is something to do and avoid duplicate consecutive
* flushes. For repeated and useless calls with Z_FINISH, we keep
* returning Z_STREAM_END instead of Z_BUF_ERROR.
*/
} else if (strm->avail_in == 0 && flush <= old_flush &&
flush != Z_FINISH) {
ERR_RETURN(strm, Z_BUF_ERROR);
}
/* User must not provide more input after the first FINISH: */
if (s->status == FINISH_STATE && strm->avail_in != 0) {
ERR_RETURN(strm, Z_BUF_ERROR);
}
/* Start a new block or continue the current one.
*/
if (strm->avail_in != 0 || s->lookahead != 0 ||
(flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
block_state bstate;
bstate = (*(configuration_table[s->level].func))(s, flush);
if (bstate == finish_started || bstate == finish_done) {
s->status = FINISH_STATE;
}
if (bstate == need_more || bstate == finish_started) {
if (strm->avail_out == 0) {
s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
}
return Z_OK;
/* If flush != Z_NO_FLUSH && avail_out == 0, the next call
* of deflate should use the same flush parameter to make sure
* that the flush is complete. So we don't have to output an
* empty block here, this will be done at next call. This also
* ensures that for a very small output buffer, we emit at most
* one empty block.
*/
}
if (bstate == block_done) {
if (flush == Z_PARTIAL_FLUSH) {
_tr_align(s);
} else { /* FULL_FLUSH or SYNC_FLUSH */
_tr_stored_block(s, (char*)0, 0L, 0);
/* For a full flush, this empty block will be recognized
* as a special marker by inflate_sync().
*/
if (flush == Z_FULL_FLUSH) {
CLEAR_HASH(s); /* forget history */
}
}
flush_pending(strm);
if (strm->avail_out == 0) {
s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
return Z_OK;
}
}
}
Assert(strm->avail_out > 0, "bug2");
if (flush != Z_FINISH) return Z_OK;
if (s->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.
*/
if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
return s->pending != 0 ? Z_OK : Z_STREAM_END;
}
/* ========================================================================= */
int ZEXPORT deflateEnd (strm)
z_streamp strm;
{
int status;
if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
status = strm->state->status;
if (status != INIT_STATE &&
status != EXTRA_STATE &&
status != NAME_STATE &&
status != COMMENT_STATE &&
status != HCRC_STATE &&
status != BUSY_STATE &&
status != FINISH_STATE) {
return Z_STREAM_ERROR;
}
/* Deallocate in reverse order of allocations: */
TRY_FREE(strm, strm->state->pending_buf);
TRY_FREE(strm, strm->state->head);
TRY_FREE(strm, strm->state->prev);
TRY_FREE(strm, strm->state->window);
ZFREE(strm, strm->state);
strm->state = Z_NULL;
return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
}
/* =========================================================================
* Copy the source state to the destination state.
* To simplify the source, this is not supported for 16-bit MSDOS (which
* doesn't have enough memory anyway to duplicate compression states).
*/
int ZEXPORT deflateCopy (dest, source)
z_streamp dest;
z_streamp source;
{
#ifdef MAXSEG_64K
return Z_STREAM_ERROR;
#else
deflate_state *ds;
deflate_state *ss;
ushf *overlay;
if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
return Z_STREAM_ERROR;
}
ss = source->state;
zmemcpy(dest, 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;
zmemcpy(ds, 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;
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 /* MAXSEG_64K */
}
/* ===========================================================================
* Read a new buffer from the current input stream, update the adler32
* and total number of bytes read. All deflate() input goes through
* this function so some applications may wish to modify it to avoid
* allocating a large strm->next_in buffer and copying from it.
* (See also flush_pending()).
*/
local int read_buf(strm, buf, size)
z_streamp strm;
Bytef *buf;
unsigned size;
{
unsigned len = strm->avail_in;
if (len > size) len = size;
if (len == 0) return 0;
strm->avail_in -= len;
if (strm->state->wrap == 1) {
strm->adler = adler32(strm->adler, strm->next_in, len);
}
#ifdef GZIP
else if (strm->state->wrap == 2) {
strm->adler = crc32(strm->adler, strm->next_in, len);
}
#endif
zmemcpy(buf, strm->next_in, len);
strm->next_in += len;
strm->total_in += len;
return (int)len;
}
/* ===========================================================================
* Initialize the "longest match" routines for a new zlib stream
*/
local void lm_init (s)
deflate_state *s;
{
s->window_size = (ulg)2L*s->w_size;
CLEAR_HASH(s);
/* Set the default configuration parameters:
*/
s->max_lazy_match = configuration_table[s->level].max_lazy;
s->good_match = configuration_table[s->level].good_length;
s->nice_match = configuration_table[s->level].nice_length;
s->max_chain_length = configuration_table[s->level].max_chain;
s->strstart = 0;