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deflate.c
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/* deflate.c -- compress data using the deflation algorithm
* Copyright (C) 1995-2016 Jean-loup Gailly and Mark Adler
* 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://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.
*
* Fiala,E.R., and Greene,D.H.
* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
*
*/
/* @(#) $Id$ */
#include "zbuild.h"
#include "deflate.h"
#include "deflate_p.h"
#include "match.h"
#include "functable.h"
const char deflate_copyright[] = " deflate 1.2.11.f Copyright 1995-2016 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
include such an acknowledgment, I would appreciate that you keep this
copyright string in the executable of your product.
*/
/* ===========================================================================
* Function prototypes.
*/
typedef block_state (*compress_func) (deflate_state *s, int flush);
/* Compression function. Returns the block state after the call. */
static int deflateStateCheck (PREFIX3(stream) *strm);
static void slide_hash (deflate_state *s);
static block_state deflate_stored (deflate_state *s, int flush);
ZLIB_INTERNAL block_state deflate_fast (deflate_state *s, int flush);
ZLIB_INTERNAL block_state deflate_quick (deflate_state *s, int flush);
#ifdef MEDIUM_STRATEGY
ZLIB_INTERNAL block_state deflate_medium (deflate_state *s, int flush);
#endif
ZLIB_INTERNAL block_state deflate_slow (deflate_state *s, int flush);
static block_state deflate_rle (deflate_state *s, int flush);
static block_state deflate_huff (deflate_state *s, int flush);
static void lm_init (deflate_state *s);
static void putShortMSB (deflate_state *s, uint16_t b);
ZLIB_INTERNAL void flush_pending (PREFIX3(stream) *strm);
ZLIB_INTERNAL unsigned read_buf (PREFIX3(stream) *strm, unsigned char *buf, unsigned size);
extern void crc_reset(deflate_state *const s);
#ifdef X86_PCLMULQDQ_CRC
extern void crc_finalize(deflate_state *const s);
#endif
extern void copy_with_crc(PREFIX3(stream) *strm, unsigned char *dst, unsigned long size);
/* ===========================================================================
* Local data
*/
#define NIL 0
/* Tail of hash chains */
/* 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 {
uint16_t good_length; /* reduce lazy search above this match length */
uint16_t max_lazy; /* do not perform lazy search above this match length */
uint16_t nice_length; /* quit search above this match length */
uint16_t max_chain;
compress_func func;
} config;
static const config configuration_table[10] = {
/* good lazy nice chain */
/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
#ifdef X86_QUICK_STRATEGY
/* 1 */ {4, 4, 8, 4, deflate_quick},
/* 2 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
#else
/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
/* 2 */ {4, 5, 16, 8, deflate_fast},
#endif
/* 3 */ {4, 6, 32, 32, deflate_fast},
#ifdef MEDIUM_STRATEGY
/* 4 */ {4, 4, 16, 16, deflate_medium}, /* lazy matches */
/* 5 */ {8, 16, 32, 32, deflate_medium},
/* 6 */ {8, 16, 128, 128, deflate_medium},
#else
/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
/* 5 */ {8, 16, 32, 32, deflate_slow},
/* 6 */ {8, 16, 128, 128, deflate_slow},
#endif
/* 7 */ {8, 32, 128, 256, deflate_slow},
/* 8 */ {32, 128, 258, 1024, deflate_slow},
/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
* For deflate_fast() (levels <= 3) good is ignored and lazy has a different
* meaning.
*/
/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
#define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0))
/* ===========================================================================
* 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; \
memset((unsigned char *)s->head, 0, (unsigned)(s->hash_size-1)*sizeof(*s->head));
/* ===========================================================================
* 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.
*/
static void slide_hash(deflate_state *s) {
unsigned n;
Pos *p;
unsigned int wsize = s->w_size;
n = s->hash_size;
p = &s->head[n];
#ifdef NOT_TWEAK_COMPILER
do {
unsigned m;
m = *--p;
*p = (Pos)(m >= wsize ? m-wsize : NIL);
} while (--n);
#else
/* As of I make this change, gcc (4.8.*) isn't able to vectorize
* this hot loop using saturated-subtraction on x86-64 architecture.
* To avoid this defect, we can change the loop such that
* o. the pointer advance forward, and
* o. demote the variable 'm' to be local to the loop, and
* choose type "Pos" (instead of 'unsigned int') for the
* variable to avoid unncessary zero-extension.
*/
{
unsigned int i;
Pos *q = p - n;
for (i = 0; i < n; i++) {
Pos m = *q;
Pos t = wsize;
*q++ = (Pos)(m >= t ? m-t: NIL);
}
}
#endif /* NOT_TWEAK_COMPILER */
n = wsize;
p = &s->prev[n];
#ifdef NOT_TWEAK_COMPILER
do {
unsigned m;
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);
#else
{
unsigned int i;
Pos *q = p - n;
for (i = 0; i < n; i++) {
Pos m = *q;
Pos t = wsize;
*q++ = (Pos)(m >= t ? m-t: NIL);
}
}
#endif /* NOT_TWEAK_COMPILER */
}
/* ========================================================================= */
int ZEXPORT PREFIX(deflateInit_)(PREFIX3(stream) *strm, int level, const char *version, int stream_size) {
return PREFIX(deflateInit2_)(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY, version, stream_size);
/* Todo: ignore strm->next_in if we use it as window */
}
/* ========================================================================= */
int ZEXPORT PREFIX(deflateInit2_)(PREFIX3(stream) *strm, int level, int method, int windowBits,
int memLevel, int strategy, const char *version, int stream_size) {
unsigned window_padding = 0;
deflate_state *s;
int wrap = 1;
static const char my_version[] = PREFIX2(VERSION);
#ifdef X86_CPUID
x86_check_features();
#endif
if (version == NULL || version[0] != my_version[0] || stream_size != sizeof(PREFIX3(stream))) {
return Z_VERSION_ERROR;
}
if (strm == NULL)
return Z_STREAM_ERROR;
strm->msg = NULL;
if (strm->zalloc == NULL) {
strm->zalloc = zcalloc;
strm->opaque = NULL;
}
if (strm->zfree == NULL)
strm->zfree = zcfree;
if (level == Z_DEFAULT_COMPRESSION)
level = 6;
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 ||
(windowBits == 8 && wrap != 1)) {
return Z_STREAM_ERROR;
}
if (windowBits == 8)
windowBits = 9; /* until 256-byte window bug fixed */
#ifdef X86_QUICK_STRATEGY
if (level == 1)
windowBits = 13;
#endif
s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
if (s == NULL)
return Z_MEM_ERROR;
strm->state = (struct internal_state *)s;
s->strm = strm;
s->status = INIT_STATE; /* to pass state test in deflateReset() */
s->wrap = wrap;
s->gzhead = NULL;
s->w_bits = (unsigned int)windowBits;
s->w_size = 1 << s->w_bits;
s->w_mask = s->w_size - 1;
#ifdef X86_SSE4_2_CRC_HASH
if (x86_cpu_has_sse42)
s->hash_bits = (unsigned int)15;
else
#endif
s->hash_bits = (unsigned int)memLevel + 7;
s->hash_size = 1 << s->hash_bits;
s->hash_mask = s->hash_size - 1;
#if !defined(__x86_64) && !defined(__i386_)
s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
#endif
#ifdef X86_PCLMULQDQ_CRC
window_padding = 8;
#endif
s->window = (unsigned char *) ZALLOC(strm, s->w_size + window_padding, 2*sizeof(unsigned char));
s->prev = (Pos *) ZALLOC(strm, s->w_size, sizeof(Pos));
memset(s->prev, 0, s->w_size * sizeof(Pos));
s->head = (Pos *) 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 */
/* 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 = (unsigned char *) ZALLOC(strm, s->lit_bufsize, 4);
s->pending_buf_size = (unsigned long)s->lit_bufsize * 4;
if (s->window == NULL || s->prev == NULL || s->head == NULL ||
s->pending_buf == NULL) {
s->status = FINISH_STATE;
strm->msg = ERR_MSG(Z_MEM_ERROR);
PREFIX(deflateEnd)(strm);
return Z_MEM_ERROR;
}
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;
s->method = (unsigned char)method;
s->block_open = 0;
return PREFIX(deflateReset)(strm);
}
/* =========================================================================
* Check for a valid deflate stream state. Return 0 if ok, 1 if not.
*/
static int deflateStateCheck (PREFIX3(stream) *strm) {
deflate_state *s;
if (strm == NULL ||
strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
return 1;
s = strm->state;
if (s == 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 PREFIX(deflateSetDictionary)(PREFIX3(stream) *strm, const unsigned char *dictionary, unsigned int dictLength) {
deflate_state *s;
unsigned int str, n;
int wrap;
uint32_t avail;
const unsigned char *next;
if (deflateStateCheck(strm) || dictionary == NULL)
return Z_STREAM_ERROR;
s = strm->state;
wrap = s->wrap;
if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead)
return Z_STREAM_ERROR;
/* when using zlib wrappers, compute Adler-32 for provided dictionary */
if (wrap == 1)
strm->adler = functable.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;
}
/* insert dictionary into window and hash */
avail = strm->avail_in;
next = strm->next_in;
strm->avail_in = dictLength;
strm->next_in = (const unsigned char *)dictionary;
functable.fill_window(s);
while (s->lookahead >= MIN_MATCH) {
str = s->strstart;
n = s->lookahead - (MIN_MATCH-1);
functable.insert_string(s, str, n);
s->strstart = str + n;
s->lookahead = MIN_MATCH-1;
functable.fill_window(s);
}
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 PREFIX(deflateGetDictionary)(PREFIX3(stream) *strm, unsigned char *dictionary, unsigned int *dictLength) {
deflate_state *s;
unsigned int 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 != NULL && len)
memcpy(dictionary, s->window + s->strstart + s->lookahead - len, len);
if (dictLength != NULL)
*dictLength = len;
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT PREFIX(deflateResetKeep)(PREFIX3(stream) *strm) {
deflate_state *s;
if (deflateStateCheck(strm)) {
return Z_STREAM_ERROR;
}
strm->total_in = strm->total_out = 0;
strm->msg = 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 =
#ifdef GZIP
s->wrap == 2 ? GZIP_STATE :
#endif
INIT_STATE;
#ifdef GZIP
if (s->wrap == 2)
crc_reset(s);
else
#endif
strm->adler = functable.adler32(0L, NULL, 0);
s->last_flush = Z_NO_FLUSH;
_tr_init(s);
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT PREFIX(deflateReset)(PREFIX3(stream) *strm) {
int ret;
ret = PREFIX(deflateResetKeep)(strm);
if (ret == Z_OK)
lm_init(strm->state);
return ret;
}
/* ========================================================================= */
int ZEXPORT PREFIX(deflateSetHeader)(PREFIX3(stream) *strm, PREFIX(gz_headerp) head) {
if (deflateStateCheck(strm) || strm->state->wrap != 2)
return Z_STREAM_ERROR;
strm->state->gzhead = head;
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT PREFIX(deflatePending)(PREFIX3(stream) *strm, uint32_t *pending, int *bits) {
if (deflateStateCheck(strm))
return Z_STREAM_ERROR;
if (pending != NULL)
*pending = strm->state->pending;
if (bits != NULL)
*bits = strm->state->bi_valid;
return Z_OK;
}
/* ========================================================================= */
int ZEXPORT PREFIX(deflatePrime)(PREFIX3(stream) *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 |= (uint16_t)((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 PREFIX(deflateParams)(PREFIX3(stream) *strm, int level, int strategy) {
deflate_state *s;
compress_func func;
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_FIXED) {
return Z_STREAM_ERROR;
}
func = configuration_table[s->level].func;
if ((strategy != s->strategy || func != configuration_table[level].func) && s->high_water) {
/* Flush the last buffer: */
int err = PREFIX(deflate)(strm, Z_BLOCK);
if (err == Z_STREAM_ERROR)
return err;
if (strm->avail_out == 0)
return Z_BUF_ERROR;
}
if (s->level != level) {
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 Z_OK;
}
/* ========================================================================= */
int ZEXPORT PREFIX(deflateTune)(PREFIX3(stream) *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 = (unsigned int)good_length;
s->max_lazy_match = (unsigned int)max_lazy;
s->nice_match = nice_length;
s->max_chain_length = (unsigned int)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.
*/
unsigned long ZEXPORT PREFIX(deflateBound)(PREFIX3(stream) *strm, unsigned long sourceLen) {
deflate_state *s;
unsigned long 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 != NULL) { /* user-supplied gzip header */
unsigned char *str;
if (s->gzhead->extra != NULL) {
wraplen += 2 + s->gzhead->extra_len;
}
str = s->gzhead->name;
if (str != NULL) {
do {
wraplen++;
} while (*str++);
}
str = s->gzhead->comment;
if (str != 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 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.
*/
static void putShortMSB(deflate_state *s, uint16_t b) {
put_byte(s, (unsigned char)(b >> 8));
put_byte(s, (unsigned char)(b & 0xff));
}
/* =========================================================================
* 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()).
*/
ZLIB_INTERNAL void flush_pending(PREFIX3(stream) *strm) {
uint32_t 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;
memcpy(strm->next_out, s->pending_out, len);
strm->next_out += len;
s->pending_out += len;
strm->total_out += len;
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 = PREFIX(crc32)(strm->adler, s->pending_buf + (beg), s->pending - (beg)); \
} while (0)
/* ========================================================================= */
int ZEXPORT PREFIX(deflate)(PREFIX3(stream) *strm, int flush) {
int old_flush; /* value of flush param for previous deflate call */
deflate_state *s;
if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) {
return Z_STREAM_ERROR;
}
s = strm->state;
if (strm->next_out == NULL || (strm->avail_in != 0 && strm->next_in == 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);
old_flush = s->last_flush;
s->last_flush = flush;
/* 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 && RANK(flush) <= RANK(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);
}
/* Write the header */
if (s->status == INIT_STATE && s->wrap == 0)
s->status = BUSY_STATE;
if (s->status == INIT_STATE) {
/* zlib header */
unsigned int header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
unsigned int 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, (uint16_t)(strm->adler >> 16));
putShortMSB(s, (uint16_t)(strm->adler));
}
strm->adler = functable.adler32(0L, 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 */
crc_reset(s);
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;
/* 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 == NULL ? 0 : 4) +
(s->gzhead->name == NULL ? 0 : 8) +
(s->gzhead->comment == NULL ? 0 : 16)
);
put_byte(s, (unsigned char)(s->gzhead->time & 0xff));
put_byte(s, (unsigned char)((s->gzhead->time >> 8) & 0xff));
put_byte(s, (unsigned char)((s->gzhead->time >> 16) & 0xff));
put_byte(s, (unsigned char)((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 = PREFIX(crc32)(strm->adler, s->pending_buf, s->pending);
s->gzindex = 0;
s->status = EXTRA_STATE;
}
}
if (s->status == EXTRA_STATE) {
if (s->gzhead->extra != NULL) {
uint32_t beg = s->pending; /* start of bytes to update crc */
uint32_t left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
while (s->pending + left > s->pending_buf_size) {
uint32_t copy = s->pending_buf_size - s->pending;
memcpy(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;
}
memcpy(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 != NULL) {
uint32_t 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 != NULL) {
uint32_t 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, (unsigned char)(strm->adler & 0xff));
put_byte(s, (unsigned char)((strm->adler >> 8) & 0xff));
crc_reset(s);
}
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 = s->level == 0 ? deflate_stored(s, flush) :
s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
s->strategy == Z_RLE ? deflate_rle(s, flush) :
#ifdef X86_QUICK_STRATEGY
(s->level == 1 && !x86_cpu_has_sse42) ? deflate_fast(s, flush) :
#endif
(*(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