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deflate.c
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deflate.c
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/* deflate.c -- compress data using the deflation algorithm
* Copyright (C) 1995-2022 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 https://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
*
*/
#include "zbuild.h"
#include "deflate.h"
#include "deflate_p.h"
#include "functable.h"
/* Avoid conflicts with zlib.h macros */
#ifdef ZLIB_COMPAT
# undef deflateInit
# undef deflateInit2
#endif
const char PREFIX(deflate_copyright)[] = " deflate 1.2.13 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
include such an acknowledgment, I would appreciate that you keep this
copyright string in the executable of your product.
*/
/* ===========================================================================
* Architecture-specific hooks.
*/
#ifdef S390_DFLTCC_DEFLATE
# include "arch/s390/dfltcc_deflate.h"
#else
/* Memory management for the deflate state. Useful for allocating arch-specific extension blocks. */
# define ZALLOC_DEFLATE_STATE(strm) ((deflate_state *)ZALLOC(strm, 1, sizeof(deflate_state)))
# define ZFREE_STATE(strm, addr) ZFREE(strm, addr)
# define ZCOPY_DEFLATE_STATE(dst, src) memcpy(dst, src, sizeof(deflate_state))
/* Memory management for the window. Useful for allocation the aligned window. */
# define ZALLOC_WINDOW(strm, items, size) ZALLOC(strm, items, size)
# define TRY_FREE_WINDOW(strm, addr) TRY_FREE(strm, addr)
/* Invoked at the beginning of deflateSetDictionary(). Useful for checking arch-specific window data. */
# define DEFLATE_SET_DICTIONARY_HOOK(strm, dict, dict_len) do {} while (0)
/* Invoked at the beginning of deflateGetDictionary(). Useful for adjusting arch-specific window data. */
# define DEFLATE_GET_DICTIONARY_HOOK(strm, dict, dict_len) do {} while (0)
/* Invoked at the end of deflateResetKeep(). Useful for initializing arch-specific extension blocks. */
# define DEFLATE_RESET_KEEP_HOOK(strm) do {} while (0)
/* Invoked at the beginning of deflateParams(). Useful for updating arch-specific compression parameters. */
# define DEFLATE_PARAMS_HOOK(strm, level, strategy, hook_flush) do {} while (0)
/* Returns whether the last deflate(flush) operation did everything it's supposed to do. */
# define DEFLATE_DONE(strm, flush) 1
/* Adjusts the upper bound on compressed data length based on compression parameters and uncompressed data length.
* Useful when arch-specific deflation code behaves differently than regular zlib-ng algorithms. */
# define DEFLATE_BOUND_ADJUST_COMPLEN(strm, complen, sourceLen) do {} while (0)
/* Returns whether an optimistic upper bound on compressed data length should *not* be used.
* Useful when arch-specific deflation code behaves differently than regular zlib-ng algorithms. */
# define DEFLATE_NEED_CONSERVATIVE_BOUND(strm) 0
/* Invoked for each deflate() call. Useful for plugging arch-specific deflation code. */
# define DEFLATE_HOOK(strm, flush, bstate) 0
/* Returns whether zlib-ng should compute a checksum. Set to 0 if arch-specific deflation code already does that. */
# define DEFLATE_NEED_CHECKSUM(strm) 1
/* Returns whether reproducibility parameter can be set to a given value. */
# define DEFLATE_CAN_SET_REPRODUCIBLE(strm, reproducible) 1
#endif
/* ===========================================================================
* Function prototypes.
*/
static int deflateStateCheck (PREFIX3(stream) *strm);
Z_INTERNAL block_state deflate_stored(deflate_state *s, int flush);
Z_INTERNAL block_state deflate_fast (deflate_state *s, int flush);
Z_INTERNAL block_state deflate_quick (deflate_state *s, int flush);
#ifndef NO_MEDIUM_STRATEGY
Z_INTERNAL block_state deflate_medium(deflate_state *s, int flush);
#endif
Z_INTERNAL block_state deflate_slow (deflate_state *s, int flush);
Z_INTERNAL block_state deflate_rle (deflate_state *s, int flush);
Z_INTERNAL block_state deflate_huff (deflate_state *s, int flush);
static void lm_set_level (deflate_state *s, int level);
static void lm_init (deflate_state *s);
Z_INTERNAL unsigned read_buf (PREFIX3(stream) *strm, unsigned char *buf, unsigned size);
extern uint32_t update_hash_roll (deflate_state *const s, uint32_t h, uint32_t val);
extern void insert_string_roll (deflate_state *const s, uint32_t str, uint32_t count);
extern Pos quick_insert_string_roll(deflate_state *const s, uint32_t str);
/* ===========================================================================
* Local data
*/
/* 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 NO_QUICK_STRATEGY
/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
/* 2 */ {4, 5, 16, 8, deflate_fast},
#else
/* 1 */ {0, 0, 0, 0, deflate_quick},
/* 2 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
#endif
#ifdef NO_MEDIUM_STRATEGY
/* 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},
#else
/* 3 */ {4, 6, 16, 6, deflate_medium},
/* 4 */ {4, 12, 32, 24, deflate_medium}, /* lazy matches */
/* 5 */ {8, 16, 32, 32, deflate_medium},
/* 6 */ {8, 16, 128, 128, deflate_medium},
#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 >= STD_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. prev[] will be initialized on the fly.
*/
#define CLEAR_HASH(s) do { \
memset((unsigned char *)s->head, 0, HASH_SIZE * sizeof(*s->head)); \
} while (0)
/* ========================================================================= */
/* This function is hidden in ZLIB_COMPAT builds. */
int32_t ZNG_CONDEXPORT PREFIX(deflateInit2)(PREFIX3(stream) *strm, int32_t level, int32_t method, int32_t windowBits,
int32_t memLevel, int32_t strategy) {
/* Todo: ignore strm->next_in if we use it as window */
uint32_t window_padding = 0;
deflate_state *s;
int wrap = 1;
if (strm == NULL)
return Z_STREAM_ERROR;
strm->msg = NULL;
if (strm->zalloc == NULL) {
strm->zalloc = PREFIX(zcalloc);
strm->opaque = NULL;
}
if (strm->zfree == NULL)
strm->zfree = PREFIX(zcfree);
if (level == Z_DEFAULT_COMPRESSION)
level = 6;
if (windowBits < 0) { /* suppress zlib wrapper */
wrap = 0;
if (windowBits < -MAX_WBITS)
return Z_STREAM_ERROR;
windowBits = -windowBits;
#ifdef GZIP
} else if (windowBits > MAX_WBITS) {
wrap = 2; /* write gzip wrapper instead */
windowBits -= 16;
#endif
}
if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || windowBits < MIN_WBITS ||
windowBits > MAX_WBITS || 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 = ZALLOC_DEFLATE_STATE(strm);
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_PCLMULQDQ_CRC
window_padding = 8;
#endif
s->window = (unsigned char *) ZALLOC_WINDOW(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, 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 = 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->block_open = 0;
s->reproducible = 0;
return PREFIX(deflateReset)(strm);
}
#ifndef ZLIB_COMPAT
int32_t Z_EXPORT PREFIX(deflateInit)(PREFIX3(stream) *strm, int32_t level) {
return PREFIX(deflateInit2)(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
}
#endif
/* Function used by zlib.h and zlib-ng version 2.0 macros */
int32_t Z_EXPORT PREFIX(deflateInit_)(PREFIX3(stream) *strm, int32_t level, const char *version, int32_t stream_size) {
if (CHECK_VER_STSIZE(version, stream_size))
return Z_VERSION_ERROR;
return PREFIX(deflateInit2)(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, Z_DEFAULT_STRATEGY);
}
/* Function used by zlib.h and zlib-ng version 2.0 macros */
int32_t Z_EXPORT PREFIX(deflateInit2_)(PREFIX3(stream) *strm, int32_t level, int32_t method, int32_t windowBits,
int32_t memLevel, int32_t strategy, const char *version, int32_t stream_size) {
if (CHECK_VER_STSIZE(version, stream_size))
return Z_VERSION_ERROR;
return PREFIX(deflateInit2)(strm, level, method, windowBits, memLevel, strategy);
}
/* =========================================================================
* 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 &&
s->status != EXTRA_STATE &&
s->status != NAME_STATE &&
s->status != COMMENT_STATE &&
s->status != HCRC_STATE &&
#endif
s->status != BUSY_STATE &&
s->status != FINISH_STATE))
return 1;
return 0;
}
/* ========================================================================= */
int32_t Z_EXPORT PREFIX(deflateSetDictionary)(PREFIX3(stream) *strm, const uint8_t *dictionary, uint32_t 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);
DEFLATE_SET_DICTIONARY_HOOK(strm, dictionary, dictLength); /* hook for IBM Z DFLTCC */
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 = 0;
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 = (z_const unsigned char *)dictionary;
PREFIX(fill_window)(s);
while (s->lookahead >= STD_MIN_MATCH) {
str = s->strstart;
n = s->lookahead - (STD_MIN_MATCH - 1);
s->insert_string(s, str, n);
s->strstart = str + n;
s->lookahead = STD_MIN_MATCH - 1;
PREFIX(fill_window)(s);
}
s->strstart += s->lookahead;
s->block_start = (int)s->strstart;
s->insert = s->lookahead;
s->lookahead = 0;
s->prev_length = 0;
s->match_available = 0;
strm->next_in = (z_const unsigned char *)next;
strm->avail_in = avail;
s->wrap = wrap;
return Z_OK;
}
/* ========================================================================= */
int32_t Z_EXPORT PREFIX(deflateGetDictionary)(PREFIX3(stream) *strm, uint8_t *dictionary, uint32_t *dictLength) {
deflate_state *s;
unsigned int len;
if (deflateStateCheck(strm))
return Z_STREAM_ERROR;
DEFLATE_GET_DICTIONARY_HOOK(strm, dictionary, dictLength); /* hook for IBM Z DFLTCC */
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;
}
/* ========================================================================= */
int32_t Z_EXPORT 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) {
strm->adler = functable.crc32_fold_reset(&s->crc_fold);
} else
#endif
strm->adler = ADLER32_INITIAL_VALUE;
s->last_flush = -2;
zng_tr_init(s);
DEFLATE_RESET_KEEP_HOOK(strm); /* hook for IBM Z DFLTCC */
return Z_OK;
}
/* ========================================================================= */
int32_t Z_EXPORT PREFIX(deflateReset)(PREFIX3(stream) *strm) {
int ret;
ret = PREFIX(deflateResetKeep)(strm);
if (ret == Z_OK)
lm_init(strm->state);
return ret;
}
/* ========================================================================= */
int32_t Z_EXPORT 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;
}
/* ========================================================================= */
int32_t Z_EXPORT PREFIX(deflatePending)(PREFIX3(stream) *strm, uint32_t *pending, int32_t *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;
}
/* ========================================================================= */
int32_t Z_EXPORT PREFIX(deflatePrime)(PREFIX3(stream) *strm, int32_t bits, int32_t value) {
deflate_state *s;
uint64_t value64 = (uint64_t)value;
int32_t put;
if (deflateStateCheck(strm))
return Z_STREAM_ERROR;
s = strm->state;
if (bits < 0 || bits > BIT_BUF_SIZE || bits > (int32_t)(sizeof(value) << 3) ||
s->sym_buf < s->pending_out + ((BIT_BUF_SIZE + 7) >> 3))
return Z_BUF_ERROR;
do {
put = BIT_BUF_SIZE - s->bi_valid;
put = MIN(put, bits);
if (s->bi_valid == 0)
s->bi_buf = value64;
else
s->bi_buf |= (value64 & ((UINT64_C(1) << put) - 1)) << s->bi_valid;
s->bi_valid += put;
zng_tr_flush_bits(s);
value64 >>= put;
bits -= put;
} while (bits);
return Z_OK;
}
/* ========================================================================= */
int32_t Z_EXPORT PREFIX(deflateParams)(PREFIX3(stream) *strm, int32_t level, int32_t strategy) {
deflate_state *s;
compress_func func;
int hook_flush = Z_NO_FLUSH;
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;
DEFLATE_PARAMS_HOOK(strm, level, strategy, &hook_flush); /* hook for IBM Z DFLTCC */
func = configuration_table[s->level].func;
if (((strategy != s->strategy || func != configuration_table[level].func) && s->last_flush != -2)
|| hook_flush != Z_NO_FLUSH) {
/* Flush the last buffer. Use Z_BLOCK mode, unless the hook requests a "stronger" one. */
int flush = RANK(hook_flush) > RANK(Z_BLOCK) ? hook_flush : Z_BLOCK;
int err = PREFIX(deflate)(strm, flush);
if (err == Z_STREAM_ERROR)
return err;
if (strm->avail_in || ((int)s->strstart - s->block_start) + s->lookahead || !DEFLATE_DONE(strm, flush))
return Z_BUF_ERROR;
}
if (s->level != level) {
if (s->level == 0 && s->matches != 0) {
if (s->matches == 1) {
functable.slide_hash(s);
} else {
CLEAR_HASH(s);
}
s->matches = 0;
}
lm_set_level(s, level);
}
s->strategy = strategy;
return Z_OK;
}
/* ========================================================================= */
int32_t Z_EXPORT PREFIX(deflateTune)(PREFIX3(stream) *strm, int32_t good_length, int32_t max_lazy, int32_t nice_length, int32_t 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 Z_EXPORT 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;
DEFLATE_BOUND_ADJUST_COMPLEN(strm, complen, sourceLen); /* hook for IBM Z DFLTCC */
/* 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 = ZLIB_WRAPLEN + (s->strstart ? 4 : 0);
break;
#ifdef GZIP
case 2: /* gzip wrapper */
wraplen = GZIP_WRAPLEN;
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 = ZLIB_WRAPLEN;
}
/* if not default parameters, return conservative bound */
if (DEFLATE_NEED_CONSERVATIVE_BOUND(strm) || /* hook for IBM Z DFLTCC */
s->w_bits != MAX_WBITS || HASH_BITS < 15) {
if (s->level == 0) {
/* upper bound for stored blocks with length 127 (memLevel == 1) --
~4% overhead plus a small constant */
complen = sourceLen + (sourceLen >> 5) + (sourceLen >> 7) + (sourceLen >> 11) + 7;
}
return complen + wraplen;
}
#ifndef NO_QUICK_STRATEGY
return sourceLen /* The source size itself */
+ (sourceLen == 0 ? 1 : 0) /* Always at least one byte for any input */
+ (sourceLen < 9 ? 1 : 0) /* One extra byte for lengths less than 9 */
+ DEFLATE_QUICK_OVERHEAD(sourceLen) /* Source encoding overhead, padded to next full byte */
+ DEFLATE_BLOCK_OVERHEAD /* Deflate block overhead bytes */
+ wraplen; /* none, zlib or gzip wrapper */
#else
return sourceLen + (sourceLen >> 4) + 7 + wraplen;
#endif
}
/* =========================================================================
* 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()).
*/
Z_INTERNAL void PREFIX(flush_pending)(PREFIX3(stream) *strm) {
uint32_t len;
deflate_state *s = strm->state;
zng_tr_flush_bits(s);
len = s->pending;
if (len > strm->avail_out)
len = strm->avail_out;
if (len == 0)
return;
Tracev((stderr, "[FLUSH]"));
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)
/* ========================================================================= */
int32_t Z_EXPORT PREFIX(deflate)(PREFIX3(stream) *strm, int32_t flush) {
int32_t 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) {
PREFIX(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);
put_short_msb(s, (uint16_t)header);
/* Save the adler32 of the preset dictionary: */
if (s->strstart != 0)
put_uint32_msb(s, strm->adler);
strm->adler = ADLER32_INITIAL_VALUE;
s->status = BUSY_STATE;
/* Compression must start with an empty pending buffer */
PREFIX(flush_pending)(strm);
if (s->pending != 0) {
s->last_flush = -1;
return Z_OK;
}
}
#ifdef GZIP
if (s->status == GZIP_STATE) {
/* gzip header */
functable.crc32_fold_reset(&s->crc_fold);
put_byte(s, 31);
put_byte(s, 139);
put_byte(s, 8);
if (s->gzhead == NULL) {
put_uint32(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 */
PREFIX(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_uint32(s, s->gzhead->time);
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_short(s, (uint16_t)s->gzhead->extra_len);
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;
PREFIX(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 */
unsigned char val;
do {
if (s->pending == s->pending_buf_size) {
HCRC_UPDATE(beg);
PREFIX(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 */
unsigned char val;
do {
if (s->pending == s->pending_buf_size) {
HCRC_UPDATE(beg);
PREFIX(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) {
PREFIX(flush_pending)(strm);
if (s->pending != 0) {
s->last_flush = -1;
return Z_OK;
}
}
put_short(s, (uint16_t)strm->adler);
functable.crc32_fold_reset(&s->crc_fold);
}
s->status = BUSY_STATE;
/* Compression must start with an empty pending buffer */
PREFIX(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 = DEFLATE_HOOK(strm, flush, &bstate) ? bstate : /* hook for IBM Z DFLTCC */
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 (bstate == block_done) {
if (flush == Z_PARTIAL_FLUSH) {
zng_tr_align(s);
} else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
zng_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 = 0;
s->insert = 0;
}
}
}
PREFIX(flush_pending)(strm);
if (strm->avail_out == 0) {
s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
return Z_OK;
}
}
}
if (flush != Z_FINISH)
return Z_OK;
/* Write the trailer */
#ifdef GZIP
if (s->wrap == 2) {
strm->adler = functable.crc32_fold_final(&s->crc_fold);
put_uint32(s, strm->adler);
put_uint32(s, (uint32_t)strm->total_in);
} else
#endif