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2140 lines
80 KiB
C
2140 lines
80 KiB
C
/* deflate.c -- compress data using the deflation algorithm
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* Copyright (C) 1995-2024 Jean-loup Gailly and Mark Adler
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* For conditions of distribution and use, see copyright notice in zlib.h
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*/
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/*
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* ALGORITHM
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*
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* The "deflation" process depends on being able to identify portions
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* of the input text which are identical to earlier input (within a
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* sliding window trailing behind the input currently being processed).
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*
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* The most straightforward technique turns out to be the fastest for
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* most input files: try all possible matches and select the longest.
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* The key feature of this algorithm is that insertions into the string
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* dictionary are very simple and thus fast, and deletions are avoided
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* completely. Insertions are performed at each input character, whereas
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* string matches are performed only when the previous match ends. So it
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* is preferable to spend more time in matches to allow very fast string
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* insertions and avoid deletions. The matching algorithm for small
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* strings is inspired from that of Rabin & Karp. A brute force approach
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* is used to find longer strings when a small match has been found.
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* A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
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* (by Leonid Broukhis).
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* A previous version of this file used a more sophisticated algorithm
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* (by Fiala and Greene) which is guaranteed to run in linear amortized
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* time, but has a larger average cost, uses more memory and is patented.
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* However the F&G algorithm may be faster for some highly redundant
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* files if the parameter max_chain_length (described below) is too large.
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*
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* ACKNOWLEDGEMENTS
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*
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* The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
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* I found it in 'freeze' written by Leonid Broukhis.
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* Thanks to many people for bug reports and testing.
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*
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* REFERENCES
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*
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* Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
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* Available in http://tools.ietf.org/html/rfc1951
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*
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* A description of the Rabin and Karp algorithm is given in the book
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* "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
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*
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* Fiala,E.R., and Greene,D.H.
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* Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
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*
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*/
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/* @(#) $Id$ */
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#include "deflate.h"
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const char deflate_copyright[] =
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" deflate 1.3.1 Copyright 1995-2024 Jean-loup Gailly and Mark Adler ";
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/*
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If you use the zlib library in a product, an acknowledgment is welcome
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in the documentation of your product. If for some reason you cannot
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include such an acknowledgment, I would appreciate that you keep this
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copyright string in the executable of your product.
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*/
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typedef enum {
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need_more, /* block not completed, need more input or more output */
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block_done, /* block flush performed */
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finish_started, /* finish started, need only more output at next deflate */
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finish_done /* finish done, accept no more input or output */
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} block_state;
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typedef block_state (*compress_func)(deflate_state *s, int flush);
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/* Compression function. Returns the block state after the call. */
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local block_state deflate_stored(deflate_state *s, int flush);
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local block_state deflate_fast(deflate_state *s, int flush);
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#ifndef FASTEST
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local block_state deflate_slow(deflate_state *s, int flush);
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#endif
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local block_state deflate_rle(deflate_state *s, int flush);
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local block_state deflate_huff(deflate_state *s, int flush);
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/* ===========================================================================
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* Local data
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*/
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#define NIL 0
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/* Tail of hash chains */
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#ifndef TOO_FAR
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# define TOO_FAR 4096
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#endif
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/* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
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/* Values for max_lazy_match, good_match and max_chain_length, depending on
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* the desired pack level (0..9). The values given below have been tuned to
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* exclude worst case performance for pathological files. Better values may be
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* found for specific files.
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*/
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typedef struct config_s {
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ush good_length; /* reduce lazy search above this match length */
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ush max_lazy; /* do not perform lazy search above this match length */
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ush nice_length; /* quit search above this match length */
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ush max_chain;
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compress_func func;
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} config;
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#ifdef FASTEST
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local const config configuration_table[2] = {
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/* good lazy nice chain */
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/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
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/* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
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#else
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local const config configuration_table[10] = {
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/* good lazy nice chain */
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/* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
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/* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
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/* 2 */ {4, 5, 16, 8, deflate_fast},
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/* 3 */ {4, 6, 32, 32, deflate_fast},
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/* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
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/* 5 */ {8, 16, 32, 32, deflate_slow},
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/* 6 */ {8, 16, 128, 128, deflate_slow},
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/* 7 */ {8, 32, 128, 256, deflate_slow},
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/* 8 */ {32, 128, 258, 1024, deflate_slow},
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/* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
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#endif
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/* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
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* For deflate_fast() (levels <= 3) good is ignored and lazy has a different
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* meaning.
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*/
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/* rank Z_BLOCK between Z_NO_FLUSH and Z_PARTIAL_FLUSH */
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#define RANK(f) (((f) * 2) - ((f) > 4 ? 9 : 0))
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/* ===========================================================================
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* Update a hash value with the given input byte
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* IN assertion: all calls to UPDATE_HASH are made with consecutive input
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* characters, so that a running hash key can be computed from the previous
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* key instead of complete recalculation each time.
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*/
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#define UPDATE_HASH(s,h,c) (h = (((h) << s->hash_shift) ^ (c)) & s->hash_mask)
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/* ===========================================================================
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* Insert string str in the dictionary and set match_head to the previous head
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* of the hash chain (the most recent string with same hash key). Return
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* the previous length of the hash chain.
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* If this file is compiled with -DFASTEST, the compression level is forced
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* to 1, and no hash chains are maintained.
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* IN assertion: all calls to INSERT_STRING are made with consecutive input
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* characters and the first MIN_MATCH bytes of str are valid (except for
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* the last MIN_MATCH-1 bytes of the input file).
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*/
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#ifdef FASTEST
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#define INSERT_STRING(s, str, match_head) \
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(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
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match_head = s->head[s->ins_h], \
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s->head[s->ins_h] = (Pos)(str))
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#else
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#define INSERT_STRING(s, str, match_head) \
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(UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
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match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
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s->head[s->ins_h] = (Pos)(str))
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#endif
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/* ===========================================================================
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* Initialize the hash table (avoiding 64K overflow for 16 bit systems).
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* prev[] will be initialized on the fly.
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*/
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#define CLEAR_HASH(s) \
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do { \
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s->head[s->hash_size - 1] = NIL; \
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zmemzero((Bytef *)s->head, \
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(unsigned)(s->hash_size - 1)*sizeof(*s->head)); \
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} while (0)
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/* ===========================================================================
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* Slide the hash table when sliding the window down (could be avoided with 32
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* bit values at the expense of memory usage). We slide even when level == 0 to
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* keep the hash table consistent if we switch back to level > 0 later.
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*/
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#if defined(__has_feature)
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# if __has_feature(memory_sanitizer)
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__attribute__((no_sanitize("memory")))
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# endif
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#endif
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local void slide_hash(deflate_state *s) {
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unsigned n, m;
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Posf *p;
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uInt wsize = s->w_size;
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n = s->hash_size;
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p = &s->head[n];
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do {
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m = *--p;
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*p = (Pos)(m >= wsize ? m - wsize : NIL);
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} while (--n);
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n = wsize;
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#ifndef FASTEST
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p = &s->prev[n];
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do {
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m = *--p;
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*p = (Pos)(m >= wsize ? m - wsize : NIL);
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/* If n is not on any hash chain, prev[n] is garbage but
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* its value will never be used.
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*/
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} while (--n);
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#endif
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}
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/* ===========================================================================
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* Read a new buffer from the current input stream, update the adler32
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* and total number of bytes read. All deflate() input goes through
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* this function so some applications may wish to modify it to avoid
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* allocating a large strm->next_in buffer and copying from it.
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* (See also flush_pending()).
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*/
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local unsigned read_buf(z_streamp strm, Bytef *buf, unsigned size) {
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unsigned len = strm->avail_in;
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if (len > size) len = size;
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if (len == 0) return 0;
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strm->avail_in -= len;
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zmemcpy(buf, strm->next_in, len);
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if (strm->state->wrap == 1) {
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strm->adler = adler32(strm->adler, buf, len);
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}
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#ifdef GZIP
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else if (strm->state->wrap == 2) {
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strm->adler = crc32(strm->adler, buf, len);
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}
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#endif
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strm->next_in += len;
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strm->total_in += len;
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return len;
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}
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/* ===========================================================================
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* Fill the window when the lookahead becomes insufficient.
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* Updates strstart and lookahead.
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*
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* IN assertion: lookahead < MIN_LOOKAHEAD
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* OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
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* At least one byte has been read, or avail_in == 0; reads are
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* performed for at least two bytes (required for the zip translate_eol
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* option -- not supported here).
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*/
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local void fill_window(deflate_state *s) {
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unsigned n;
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unsigned more; /* Amount of free space at the end of the window. */
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uInt wsize = s->w_size;
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Assert(s->lookahead < MIN_LOOKAHEAD, "already enough lookahead");
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do {
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more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
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/* Deal with !@#$% 64K limit: */
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if (sizeof(int) <= 2) {
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if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
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more = wsize;
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} else if (more == (unsigned)(-1)) {
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/* Very unlikely, but possible on 16 bit machine if
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* strstart == 0 && lookahead == 1 (input done a byte at time)
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*/
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more--;
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}
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}
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/* If the window is almost full and there is insufficient lookahead,
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* move the upper half to the lower one to make room in the upper half.
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*/
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if (s->strstart >= wsize + MAX_DIST(s)) {
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zmemcpy(s->window, s->window + wsize, (unsigned)wsize - more);
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s->match_start -= wsize;
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s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
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s->block_start -= (long) wsize;
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if (s->insert > s->strstart)
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s->insert = s->strstart;
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slide_hash(s);
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more += wsize;
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}
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if (s->strm->avail_in == 0) break;
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/* If there was no sliding:
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* strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
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* more == window_size - lookahead - strstart
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* => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
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* => more >= window_size - 2*WSIZE + 2
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* In the BIG_MEM or MMAP case (not yet supported),
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* window_size == input_size + MIN_LOOKAHEAD &&
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* strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
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* Otherwise, window_size == 2*WSIZE so more >= 2.
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* If there was sliding, more >= WSIZE. So in all cases, more >= 2.
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*/
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Assert(more >= 2, "more < 2");
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n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
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s->lookahead += n;
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/* Initialize the hash value now that we have some input: */
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if (s->lookahead + s->insert >= MIN_MATCH) {
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uInt str = s->strstart - s->insert;
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s->ins_h = s->window[str];
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UPDATE_HASH(s, s->ins_h, s->window[str + 1]);
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#if MIN_MATCH != 3
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Call UPDATE_HASH() MIN_MATCH-3 more times
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#endif
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while (s->insert) {
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UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
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#ifndef FASTEST
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s->prev[str & s->w_mask] = s->head[s->ins_h];
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#endif
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s->head[s->ins_h] = (Pos)str;
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str++;
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s->insert--;
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if (s->lookahead + s->insert < MIN_MATCH)
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break;
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}
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}
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/* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
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* but this is not important since only literal bytes will be emitted.
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*/
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} while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
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/* If the WIN_INIT bytes after the end of the current data have never been
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* written, then zero those bytes in order to avoid memory check reports of
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* the use of uninitialized (or uninitialised as Julian writes) bytes by
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* the longest match routines. Update the high water mark for the next
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* time through here. WIN_INIT is set to MAX_MATCH since the longest match
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* routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
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*/
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if (s->high_water < s->window_size) {
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ulg curr = s->strstart + (ulg)(s->lookahead);
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ulg init;
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if (s->high_water < curr) {
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/* Previous high water mark below current data -- zero WIN_INIT
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* bytes or up to end of window, whichever is less.
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*/
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init = s->window_size - curr;
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if (init > WIN_INIT)
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init = WIN_INIT;
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zmemzero(s->window + curr, (unsigned)init);
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s->high_water = curr + init;
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}
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else if (s->high_water < (ulg)curr + WIN_INIT) {
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/* High water mark at or above current data, but below current data
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* plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
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* to end of window, whichever is less.
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*/
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init = (ulg)curr + WIN_INIT - s->high_water;
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if (init > s->window_size - s->high_water)
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init = s->window_size - s->high_water;
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zmemzero(s->window + s->high_water, (unsigned)init);
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s->high_water += init;
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}
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}
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Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
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"not enough room for search");
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}
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/* ========================================================================= */
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int ZEXPORT deflateInit_(z_streamp strm, int level, const char *version,
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int stream_size) {
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return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
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Z_DEFAULT_STRATEGY, version, stream_size);
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/* To do: ignore strm->next_in if we use it as window */
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}
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/* ========================================================================= */
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int ZEXPORT deflateInit2_(z_streamp strm, int level, int method,
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int windowBits, int memLevel, int strategy,
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const char *version, int stream_size) {
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deflate_state *s;
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int wrap = 1;
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static const char my_version[] = ZLIB_VERSION;
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if (version == Z_NULL || version[0] != my_version[0] ||
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stream_size != sizeof(z_stream)) {
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return Z_VERSION_ERROR;
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}
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if (strm == Z_NULL) return Z_STREAM_ERROR;
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strm->msg = Z_NULL;
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if (strm->zalloc == (alloc_func)0) {
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#ifdef Z_SOLO
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return Z_STREAM_ERROR;
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#else
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strm->zalloc = zcalloc;
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strm->opaque = (voidpf)0;
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#endif
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}
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if (strm->zfree == (free_func)0)
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#ifdef Z_SOLO
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return Z_STREAM_ERROR;
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#else
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strm->zfree = zcfree;
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#endif
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#ifdef FASTEST
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if (level != 0) level = 1;
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#else
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if (level == Z_DEFAULT_COMPRESSION) level = 6;
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#endif
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if (windowBits < 0) { /* suppress zlib wrapper */
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wrap = 0;
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if (windowBits < -15)
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return Z_STREAM_ERROR;
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windowBits = -windowBits;
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}
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#ifdef GZIP
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else if (windowBits > 15) {
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wrap = 2; /* write gzip wrapper instead */
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windowBits -= 16;
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}
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#endif
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if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
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windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
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strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) {
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return Z_STREAM_ERROR;
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}
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if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
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s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
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if (s == Z_NULL) return Z_MEM_ERROR;
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strm->state = (struct internal_state FAR *)s;
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s->strm = strm;
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s->status = INIT_STATE; /* to pass state test in deflateReset() */
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s->wrap = wrap;
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s->gzhead = Z_NULL;
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s->w_bits = (uInt)windowBits;
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s->w_size = 1 << s->w_bits;
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s->w_mask = s->w_size - 1;
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s->hash_bits = (uInt)memLevel + 7;
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s->hash_size = 1 << s->hash_bits;
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s->hash_mask = s->hash_size - 1;
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s->hash_shift = ((s->hash_bits + MIN_MATCH-1) / MIN_MATCH);
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s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
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s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
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s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
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s->high_water = 0; /* nothing written to s->window yet */
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s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
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|
|
/* We overlay pending_buf and sym_buf. This works since the average size
|
|
* for length/distance pairs over any compressed block is assured to be 31
|
|
* bits or less.
|
|
*
|
|
* Analysis: The longest fixed codes are a length code of 8 bits plus 5
|
|
* extra bits, for lengths 131 to 257. The longest fixed distance codes are
|
|
* 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest
|
|
* possible fixed-codes length/distance pair is then 31 bits total.
|
|
*
|
|
* sym_buf starts one-fourth of the way into pending_buf. So there are
|
|
* three bytes in sym_buf for every four bytes in pending_buf. Each symbol
|
|
* in sym_buf is three bytes -- two for the distance and one for the
|
|
* literal/length. As each symbol is consumed, the pointer to the next
|
|
* sym_buf value to read moves forward three bytes. From that symbol, up to
|
|
* 31 bits are written to pending_buf. The closest the written pending_buf
|
|
* bits gets to the next sym_buf symbol to read is just before the last
|
|
* code is written. At that time, 31*(n - 2) bits have been written, just
|
|
* after 24*(n - 2) bits have been consumed from sym_buf. sym_buf starts at
|
|
* 8*n bits into pending_buf. (Note that the symbol buffer fills when n - 1
|
|
* symbols are written.) The closest the writing gets to what is unread is
|
|
* then n + 14 bits. Here n is lit_bufsize, which is 16384 by default, and
|
|
* can range from 128 to 32768.
|
|
*
|
|
* Therefore, at a minimum, there are 142 bits of space between what is
|
|
* written and what is read in the overlain buffers, so the symbols cannot
|
|
* be overwritten by the compressed data. That space is actually 139 bits,
|
|
* due to the three-bit fixed-code block header.
|
|
*
|
|
* That covers the case where either Z_FIXED is specified, forcing fixed
|
|
* codes, or when the use of fixed codes is chosen, because that choice
|
|
* results in a smaller compressed block than dynamic codes. That latter
|
|
* condition then assures that the above analysis also covers all dynamic
|
|
* blocks. A dynamic-code block will only be chosen to be emitted if it has
|
|
* fewer bits than a fixed-code block would for the same set of symbols.
|
|
* Therefore its average symbol length is assured to be less than 31. So
|
|
* the compressed data for a dynamic block also cannot overwrite the
|
|
* symbols from which it is being constructed.
|
|
*/
|
|
|
|
s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, LIT_BUFS);
|
|
s->pending_buf_size = (ulg)s->lit_bufsize * 4;
|
|
|
|
if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
|
|
s->pending_buf == Z_NULL) {
|
|
s->status = FINISH_STATE;
|
|
strm->msg = ERR_MSG(Z_MEM_ERROR);
|
|
deflateEnd (strm);
|
|
return Z_MEM_ERROR;
|
|
}
|
|
#ifdef LIT_MEM
|
|
s->d_buf = (ushf *)(s->pending_buf + (s->lit_bufsize << 1));
|
|
s->l_buf = s->pending_buf + (s->lit_bufsize << 2);
|
|
s->sym_end = s->lit_bufsize - 1;
|
|
#else
|
|
s->sym_buf = s->pending_buf + s->lit_bufsize;
|
|
s->sym_end = (s->lit_bufsize - 1) * 3;
|
|
#endif
|
|
/* 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 = (Byte)method;
|
|
|
|
return deflateReset(strm);
|
|
}
|
|
|
|
/* =========================================================================
|
|
* Check for a valid deflate stream state. Return 0 if ok, 1 if not.
|
|
*/
|
|
local int deflateStateCheck(z_streamp strm) {
|
|
deflate_state *s;
|
|
if (strm == Z_NULL ||
|
|
strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0)
|
|
return 1;
|
|
s = strm->state;
|
|
if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE &&
|
|
#ifdef GZIP
|
|
s->status != GZIP_STATE &&
|
|
#endif
|
|
s->status != EXTRA_STATE &&
|
|
s->status != NAME_STATE &&
|
|
s->status != COMMENT_STATE &&
|
|
s->status != HCRC_STATE &&
|
|
s->status != BUSY_STATE &&
|
|
s->status != FINISH_STATE))
|
|
return 1;
|
|
return 0;
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
int ZEXPORT deflateSetDictionary(z_streamp strm, const Bytef *dictionary,
|
|
uInt dictLength) {
|
|
deflate_state *s;
|
|
uInt str, n;
|
|
int wrap;
|
|
unsigned avail;
|
|
z_const unsigned char *next;
|
|
|
|
if (deflateStateCheck(strm) || dictionary == Z_NULL)
|
|
return Z_STREAM_ERROR;
|
|
s = strm->state;
|
|
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 = 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 = (z_const Bytef *)dictionary;
|
|
fill_window(s);
|
|
while (s->lookahead >= MIN_MATCH) {
|
|
str = s->strstart;
|
|
n = s->lookahead - (MIN_MATCH-1);
|
|
do {
|
|
UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]);
|
|
#ifndef FASTEST
|
|
s->prev[str & s->w_mask] = s->head[s->ins_h];
|
|
#endif
|
|
s->head[s->ins_h] = (Pos)str;
|
|
str++;
|
|
} while (--n);
|
|
s->strstart = str;
|
|
s->lookahead = MIN_MATCH-1;
|
|
fill_window(s);
|
|
}
|
|
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 deflateGetDictionary(z_streamp strm, Bytef *dictionary,
|
|
uInt *dictLength) {
|
|
deflate_state *s;
|
|
uInt len;
|
|
|
|
if (deflateStateCheck(strm))
|
|
return Z_STREAM_ERROR;
|
|
s = strm->state;
|
|
len = s->strstart + s->lookahead;
|
|
if (len > s->w_size)
|
|
len = s->w_size;
|
|
if (dictionary != Z_NULL && len)
|
|
zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len);
|
|
if (dictLength != Z_NULL)
|
|
*dictLength = len;
|
|
return Z_OK;
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
int ZEXPORT deflateResetKeep(z_streamp strm) {
|
|
deflate_state *s;
|
|
|
|
if (deflateStateCheck(strm)) {
|
|
return Z_STREAM_ERROR;
|
|
}
|
|
|
|
strm->total_in = strm->total_out = 0;
|
|
strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
|
|
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;
|
|
strm->adler =
|
|
#ifdef GZIP
|
|
s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
|
|
#endif
|
|
adler32(0L, Z_NULL, 0);
|
|
s->last_flush = -2;
|
|
|
|
_tr_init(s);
|
|
|
|
return Z_OK;
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Initialize the "longest match" routines for a new zlib stream
|
|
*/
|
|
local void lm_init(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;
|
|
s->block_start = 0L;
|
|
s->lookahead = 0;
|
|
s->insert = 0;
|
|
s->match_length = s->prev_length = MIN_MATCH-1;
|
|
s->match_available = 0;
|
|
s->ins_h = 0;
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
int ZEXPORT deflateReset(z_streamp strm) {
|
|
int ret;
|
|
|
|
ret = deflateResetKeep(strm);
|
|
if (ret == Z_OK)
|
|
lm_init(strm->state);
|
|
return ret;
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
int ZEXPORT deflateSetHeader(z_streamp strm, gz_headerp head) {
|
|
if (deflateStateCheck(strm) || strm->state->wrap != 2)
|
|
return Z_STREAM_ERROR;
|
|
strm->state->gzhead = head;
|
|
return Z_OK;
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
int ZEXPORT deflatePending(z_streamp strm, unsigned *pending, int *bits) {
|
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
|
|
if (pending != Z_NULL)
|
|
*pending = strm->state->pending;
|
|
if (bits != Z_NULL)
|
|
*bits = strm->state->bi_valid;
|
|
return Z_OK;
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
int ZEXPORT deflatePrime(z_streamp strm, int bits, int value) {
|
|
deflate_state *s;
|
|
int put;
|
|
|
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
|
|
s = strm->state;
|
|
#ifdef LIT_MEM
|
|
if (bits < 0 || bits > 16 ||
|
|
(uchf *)s->d_buf < s->pending_out + ((Buf_size + 7) >> 3))
|
|
return Z_BUF_ERROR;
|
|
#else
|
|
if (bits < 0 || bits > 16 ||
|
|
s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3))
|
|
return Z_BUF_ERROR;
|
|
#endif
|
|
do {
|
|
put = Buf_size - s->bi_valid;
|
|
if (put > bits)
|
|
put = bits;
|
|
s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid);
|
|
s->bi_valid += put;
|
|
_tr_flush_bits(s);
|
|
value >>= put;
|
|
bits -= put;
|
|
} while (bits);
|
|
return Z_OK;
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
int ZEXPORT deflateParams(z_streamp strm, int level, int strategy) {
|
|
deflate_state *s;
|
|
compress_func func;
|
|
|
|
if (deflateStateCheck(strm)) 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 ((strategy != s->strategy || func != configuration_table[level].func) &&
|
|
s->last_flush != -2) {
|
|
/* Flush the last buffer: */
|
|
int err = deflate(strm, Z_BLOCK);
|
|
if (err == Z_STREAM_ERROR)
|
|
return err;
|
|
if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead)
|
|
return Z_BUF_ERROR;
|
|
}
|
|
if (s->level != level) {
|
|
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 deflateTune(z_streamp strm, int good_length, int max_lazy,
|
|
int nice_length, int max_chain) {
|
|
deflate_state *s;
|
|
|
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
|
|
s = strm->state;
|
|
s->good_match = (uInt)good_length;
|
|
s->max_lazy_match = (uInt)max_lazy;
|
|
s->nice_match = nice_length;
|
|
s->max_chain_length = (uInt)max_chain;
|
|
return Z_OK;
|
|
}
|
|
|
|
/* =========================================================================
|
|
* For the default windowBits of 15 and memLevel of 8, this function returns a
|
|
* close to exact, as well as small, upper bound on the compressed size. This
|
|
* is an expansion of ~0.03%, plus a small constant.
|
|
*
|
|
* For any setting other than those defaults for windowBits and memLevel, one
|
|
* of two worst case bounds is returned. This is at most an expansion of ~4% or
|
|
* ~13%, plus a small constant.
|
|
*
|
|
* Both the 0.03% and 4% derive from the overhead of stored blocks. The first
|
|
* one is for stored blocks of 16383 bytes (memLevel == 8), whereas the second
|
|
* is for stored blocks of 127 bytes (the worst case memLevel == 1). The
|
|
* expansion results from five bytes of header for each stored block.
|
|
*
|
|
* The larger expansion of 13% results from a window size less than or equal to
|
|
* the symbols buffer size (windowBits <= memLevel + 7). In that case some of
|
|
* the data being compressed may have slid out of the sliding window, impeding
|
|
* a stored block from being emitted. Then the only choice is a fixed or
|
|
* dynamic block, where a fixed block limits the maximum expansion to 9 bits
|
|
* per 8-bit byte, plus 10 bits for every block. The smallest block size for
|
|
* which this can occur is 255 (memLevel == 2).
|
|
*
|
|
* Shifts are used to approximate divisions, for speed.
|
|
*/
|
|
uLong ZEXPORT deflateBound(z_streamp strm, uLong sourceLen) {
|
|
deflate_state *s;
|
|
uLong fixedlen, storelen, wraplen;
|
|
|
|
/* upper bound for fixed blocks with 9-bit literals and length 255
|
|
(memLevel == 2, which is the lowest that may not use stored blocks) --
|
|
~13% overhead plus a small constant */
|
|
fixedlen = sourceLen + (sourceLen >> 3) + (sourceLen >> 8) +
|
|
(sourceLen >> 9) + 4;
|
|
|
|
/* upper bound for stored blocks with length 127 (memLevel == 1) --
|
|
~4% overhead plus a small constant */
|
|
storelen = sourceLen + (sourceLen >> 5) + (sourceLen >> 7) +
|
|
(sourceLen >> 11) + 7;
|
|
|
|
/* if can't get parameters, return larger bound plus a zlib wrapper */
|
|
if (deflateStateCheck(strm))
|
|
return (fixedlen > storelen ? fixedlen : storelen) + 6;
|
|
|
|
/* compute wrapper length */
|
|
s = strm->state;
|
|
switch (s->wrap) {
|
|
case 0: /* raw deflate */
|
|
wraplen = 0;
|
|
break;
|
|
case 1: /* zlib wrapper */
|
|
wraplen = 6 + (s->strstart ? 4 : 0);
|
|
break;
|
|
#ifdef GZIP
|
|
case 2: /* gzip wrapper */
|
|
wraplen = 18;
|
|
if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
|
|
Bytef *str;
|
|
if (s->gzhead->extra != Z_NULL)
|
|
wraplen += 2 + s->gzhead->extra_len;
|
|
str = s->gzhead->name;
|
|
if (str != Z_NULL)
|
|
do {
|
|
wraplen++;
|
|
} while (*str++);
|
|
str = s->gzhead->comment;
|
|
if (str != Z_NULL)
|
|
do {
|
|
wraplen++;
|
|
} while (*str++);
|
|
if (s->gzhead->hcrc)
|
|
wraplen += 2;
|
|
}
|
|
break;
|
|
#endif
|
|
default: /* for compiler happiness */
|
|
wraplen = 6;
|
|
}
|
|
|
|
/* if not default parameters, return one of the conservative bounds */
|
|
if (s->w_bits != 15 || s->hash_bits != 8 + 7)
|
|
return (s->w_bits <= s->hash_bits && s->level ? fixedlen : storelen) +
|
|
wraplen;
|
|
|
|
/* default settings: return tight bound for that case -- ~0.03% overhead
|
|
plus a small constant */
|
|
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.
|
|
*/
|
|
local void putShortMSB(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, except for
|
|
* some deflate_stored() output, goes through this function so some
|
|
* applications may wish to modify it to avoid allocating a large
|
|
* strm->next_out buffer and copying into it. (See also read_buf()).
|
|
*/
|
|
local void flush_pending(z_streamp strm) {
|
|
unsigned len;
|
|
deflate_state *s = strm->state;
|
|
|
|
_tr_flush_bits(s);
|
|
len = s->pending;
|
|
if (len > strm->avail_out) len = strm->avail_out;
|
|
if (len == 0) return;
|
|
|
|
zmemcpy(strm->next_out, 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 = crc32(strm->adler, s->pending_buf + (beg), \
|
|
s->pending - (beg)); \
|
|
} while (0)
|
|
|
|
/* ========================================================================= */
|
|
int ZEXPORT deflate(z_streamp 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 == Z_NULL ||
|
|
(strm->avail_in != 0 && strm->next_in == Z_NULL) ||
|
|
(s->status == FINISH_STATE && flush != Z_FINISH)) {
|
|
ERR_RETURN(strm, Z_STREAM_ERROR);
|
|
}
|
|
if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
|
|
|
|
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 */
|
|
uInt header = (Z_DEFLATED + ((s->w_bits - 8) << 4)) << 8;
|
|
uInt level_flags;
|
|
|
|
if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
|
|
level_flags = 0;
|
|
else if (s->level < 6)
|
|
level_flags = 1;
|
|
else if (s->level == 6)
|
|
level_flags = 2;
|
|
else
|
|
level_flags = 3;
|
|
header |= (level_flags << 6);
|
|
if (s->strstart != 0) header |= PRESET_DICT;
|
|
header += 31 - (header % 31);
|
|
|
|
putShortMSB(s, header);
|
|
|
|
/* Save the adler32 of the preset dictionary: */
|
|
if (s->strstart != 0) {
|
|
putShortMSB(s, (uInt)(strm->adler >> 16));
|
|
putShortMSB(s, (uInt)(strm->adler & 0xffff));
|
|
}
|
|
strm->adler = adler32(0L, Z_NULL, 0);
|
|
s->status = BUSY_STATE;
|
|
|
|
/* Compression must start with an empty pending buffer */
|
|
flush_pending(strm);
|
|
if (s->pending != 0) {
|
|
s->last_flush = -1;
|
|
return Z_OK;
|
|
}
|
|
}
|
|
#ifdef GZIP
|
|
if (s->status == GZIP_STATE) {
|
|
/* gzip header */
|
|
strm->adler = crc32(0L, Z_NULL, 0);
|
|
put_byte(s, 31);
|
|
put_byte(s, 139);
|
|
put_byte(s, 8);
|
|
if (s->gzhead == Z_NULL) {
|
|
put_byte(s, 0);
|
|
put_byte(s, 0);
|
|
put_byte(s, 0);
|
|
put_byte(s, 0);
|
|
put_byte(s, 0);
|
|
put_byte(s, s->level == 9 ? 2 :
|
|
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
|
|
4 : 0));
|
|
put_byte(s, OS_CODE);
|
|
s->status = BUSY_STATE;
|
|
|
|
/* Compression must start with an empty pending buffer */
|
|
flush_pending(strm);
|
|
if (s->pending != 0) {
|
|
s->last_flush = -1;
|
|
return Z_OK;
|
|
}
|
|
}
|
|
else {
|
|
put_byte(s, (s->gzhead->text ? 1 : 0) +
|
|
(s->gzhead->hcrc ? 2 : 0) +
|
|
(s->gzhead->extra == Z_NULL ? 0 : 4) +
|
|
(s->gzhead->name == Z_NULL ? 0 : 8) +
|
|
(s->gzhead->comment == Z_NULL ? 0 : 16)
|
|
);
|
|
put_byte(s, (Byte)(s->gzhead->time & 0xff));
|
|
put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
|
|
put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
|
|
put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
|
|
put_byte(s, s->level == 9 ? 2 :
|
|
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
|
|
4 : 0));
|
|
put_byte(s, s->gzhead->os & 0xff);
|
|
if (s->gzhead->extra != Z_NULL) {
|
|
put_byte(s, s->gzhead->extra_len & 0xff);
|
|
put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
|
|
}
|
|
if (s->gzhead->hcrc)
|
|
strm->adler = crc32(strm->adler, s->pending_buf,
|
|
s->pending);
|
|
s->gzindex = 0;
|
|
s->status = EXTRA_STATE;
|
|
}
|
|
}
|
|
if (s->status == EXTRA_STATE) {
|
|
if (s->gzhead->extra != Z_NULL) {
|
|
ulg beg = s->pending; /* start of bytes to update crc */
|
|
uInt left = (s->gzhead->extra_len & 0xffff) - s->gzindex;
|
|
while (s->pending + left > s->pending_buf_size) {
|
|
uInt copy = s->pending_buf_size - s->pending;
|
|
zmemcpy(s->pending_buf + s->pending,
|
|
s->gzhead->extra + s->gzindex, copy);
|
|
s->pending = s->pending_buf_size;
|
|
HCRC_UPDATE(beg);
|
|
s->gzindex += copy;
|
|
flush_pending(strm);
|
|
if (s->pending != 0) {
|
|
s->last_flush = -1;
|
|
return Z_OK;
|
|
}
|
|
beg = 0;
|
|
left -= copy;
|
|
}
|
|
zmemcpy(s->pending_buf + s->pending,
|
|
s->gzhead->extra + s->gzindex, left);
|
|
s->pending += left;
|
|
HCRC_UPDATE(beg);
|
|
s->gzindex = 0;
|
|
}
|
|
s->status = NAME_STATE;
|
|
}
|
|
if (s->status == NAME_STATE) {
|
|
if (s->gzhead->name != Z_NULL) {
|
|
ulg beg = s->pending; /* start of bytes to update crc */
|
|
int val;
|
|
do {
|
|
if (s->pending == s->pending_buf_size) {
|
|
HCRC_UPDATE(beg);
|
|
flush_pending(strm);
|
|
if (s->pending != 0) {
|
|
s->last_flush = -1;
|
|
return Z_OK;
|
|
}
|
|
beg = 0;
|
|
}
|
|
val = s->gzhead->name[s->gzindex++];
|
|
put_byte(s, val);
|
|
} while (val != 0);
|
|
HCRC_UPDATE(beg);
|
|
s->gzindex = 0;
|
|
}
|
|
s->status = COMMENT_STATE;
|
|
}
|
|
if (s->status == COMMENT_STATE) {
|
|
if (s->gzhead->comment != Z_NULL) {
|
|
ulg beg = s->pending; /* start of bytes to update crc */
|
|
int val;
|
|
do {
|
|
if (s->pending == s->pending_buf_size) {
|
|
HCRC_UPDATE(beg);
|
|
flush_pending(strm);
|
|
if (s->pending != 0) {
|
|
s->last_flush = -1;
|
|
return Z_OK;
|
|
}
|
|
beg = 0;
|
|
}
|
|
val = s->gzhead->comment[s->gzindex++];
|
|
put_byte(s, val);
|
|
} while (val != 0);
|
|
HCRC_UPDATE(beg);
|
|
}
|
|
s->status = HCRC_STATE;
|
|
}
|
|
if (s->status == HCRC_STATE) {
|
|
if (s->gzhead->hcrc) {
|
|
if (s->pending + 2 > s->pending_buf_size) {
|
|
flush_pending(strm);
|
|
if (s->pending != 0) {
|
|
s->last_flush = -1;
|
|
return Z_OK;
|
|
}
|
|
}
|
|
put_byte(s, (Byte)(strm->adler & 0xff));
|
|
put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
|
|
strm->adler = crc32(0L, Z_NULL, 0);
|
|
}
|
|
s->status = BUSY_STATE;
|
|
|
|
/* Compression must start with an empty pending buffer */
|
|
flush_pending(strm);
|
|
if (s->pending != 0) {
|
|
s->last_flush = -1;
|
|
return Z_OK;
|
|
}
|
|
}
|
|
#endif
|
|
|
|
/* Start a new block or continue the current one.
|
|
*/
|
|
if (strm->avail_in != 0 || s->lookahead != 0 ||
|
|
(flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
|
|
block_state bstate;
|
|
|
|
bstate = 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) {
|
|
_tr_align(s);
|
|
} else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
|
|
_tr_stored_block(s, (char*)0, 0L, 0);
|
|
/* For a full flush, this empty block will be recognized
|
|
* as a special marker by inflate_sync().
|
|
*/
|
|
if (flush == Z_FULL_FLUSH) {
|
|
CLEAR_HASH(s); /* forget history */
|
|
if (s->lookahead == 0) {
|
|
s->strstart = 0;
|
|
s->block_start = 0L;
|
|
s->insert = 0;
|
|
}
|
|
}
|
|
}
|
|
flush_pending(strm);
|
|
if (strm->avail_out == 0) {
|
|
s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
|
|
return Z_OK;
|
|
}
|
|
}
|
|
}
|
|
|
|
if (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(z_streamp strm) {
|
|
int status;
|
|
|
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR;
|
|
|
|
status = strm->state->status;
|
|
|
|
/* 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(z_streamp dest, z_streamp source) {
|
|
#ifdef MAXSEG_64K
|
|
(void)dest;
|
|
(void)source;
|
|
return Z_STREAM_ERROR;
|
|
#else
|
|
deflate_state *ds;
|
|
deflate_state *ss;
|
|
|
|
|
|
if (deflateStateCheck(source) || dest == Z_NULL) {
|
|
return Z_STREAM_ERROR;
|
|
}
|
|
|
|
ss = source->state;
|
|
|
|
zmemcpy((voidpf)dest, (voidpf)source, sizeof(z_stream));
|
|
|
|
ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
|
|
if (ds == Z_NULL) return Z_MEM_ERROR;
|
|
dest->state = (struct internal_state FAR *) ds;
|
|
zmemcpy((voidpf)ds, (voidpf)ss, sizeof(deflate_state));
|
|
ds->strm = dest;
|
|
|
|
ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
|
|
ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
|
|
ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
|
|
ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, LIT_BUFS);
|
|
|
|
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((voidpf)ds->prev, (voidpf)ss->prev, ds->w_size * sizeof(Pos));
|
|
zmemcpy((voidpf)ds->head, (voidpf)ss->head, ds->hash_size * sizeof(Pos));
|
|
zmemcpy(ds->pending_buf, ss->pending_buf, ds->lit_bufsize * LIT_BUFS);
|
|
|
|
ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
|
|
#ifdef LIT_MEM
|
|
ds->d_buf = (ushf *)(ds->pending_buf + (ds->lit_bufsize << 1));
|
|
ds->l_buf = ds->pending_buf + (ds->lit_bufsize << 2);
|
|
#else
|
|
ds->sym_buf = ds->pending_buf + ds->lit_bufsize;
|
|
#endif
|
|
|
|
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 */
|
|
}
|
|
|
|
#ifndef FASTEST
|
|
/* ===========================================================================
|
|
* Set match_start to the longest match starting at the given string and
|
|
* return its length. Matches shorter or equal to prev_length are discarded,
|
|
* in which case the result is equal to prev_length and match_start is
|
|
* garbage.
|
|
* IN assertions: cur_match is the head of the hash chain for the current
|
|
* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
|
|
* OUT assertion: the match length is not greater than s->lookahead.
|
|
*/
|
|
local uInt longest_match(deflate_state *s, IPos cur_match) {
|
|
unsigned chain_length = s->max_chain_length;/* max hash chain length */
|
|
register Bytef *scan = s->window + s->strstart; /* current string */
|
|
register Bytef *match; /* matched string */
|
|
register int len; /* length of current match */
|
|
int best_len = (int)s->prev_length; /* best match length so far */
|
|
int nice_match = s->nice_match; /* stop if match long enough */
|
|
IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
|
|
s->strstart - (IPos)MAX_DIST(s) : NIL;
|
|
/* Stop when cur_match becomes <= limit. To simplify the code,
|
|
* we prevent matches with the string of window index 0.
|
|
*/
|
|
Posf *prev = s->prev;
|
|
uInt wmask = s->w_mask;
|
|
|
|
#ifdef UNALIGNED_OK
|
|
/* Compare two bytes at a time. Note: this is not always beneficial.
|
|
* Try with and without -DUNALIGNED_OK to check.
|
|
*/
|
|
register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
|
|
register ush scan_start = *(ushf*)scan;
|
|
register ush scan_end = *(ushf*)(scan + best_len - 1);
|
|
#else
|
|
register Bytef *strend = s->window + s->strstart + MAX_MATCH;
|
|
register Byte scan_end1 = scan[best_len - 1];
|
|
register Byte scan_end = scan[best_len];
|
|
#endif
|
|
|
|
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
|
|
* It is easy to get rid of this optimization if necessary.
|
|
*/
|
|
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
|
|
|
|
/* Do not waste too much time if we already have a good match: */
|
|
if (s->prev_length >= s->good_match) {
|
|
chain_length >>= 2;
|
|
}
|
|
/* Do not look for matches beyond the end of the input. This is necessary
|
|
* to make deflate deterministic.
|
|
*/
|
|
if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead;
|
|
|
|
Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
|
|
"need lookahead");
|
|
|
|
do {
|
|
Assert(cur_match < s->strstart, "no future");
|
|
match = s->window + cur_match;
|
|
|
|
/* Skip to next match if the match length cannot increase
|
|
* or if the match length is less than 2. Note that the checks below
|
|
* for insufficient lookahead only occur occasionally for performance
|
|
* reasons. Therefore uninitialized memory will be accessed, and
|
|
* conditional jumps will be made that depend on those values.
|
|
* However the length of the match is limited to the lookahead, so
|
|
* the output of deflate is not affected by the uninitialized values.
|
|
*/
|
|
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
|
|
/* This code assumes sizeof(unsigned short) == 2. Do not use
|
|
* UNALIGNED_OK if your compiler uses a different size.
|
|
*/
|
|
if (*(ushf*)(match + best_len - 1) != scan_end ||
|
|
*(ushf*)match != scan_start) continue;
|
|
|
|
/* It is not necessary to compare scan[2] and match[2] since they are
|
|
* always equal when the other bytes match, given that the hash keys
|
|
* are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
|
|
* strstart + 3, + 5, up to strstart + 257. We check for insufficient
|
|
* lookahead only every 4th comparison; the 128th check will be made
|
|
* at strstart + 257. If MAX_MATCH-2 is not a multiple of 8, it is
|
|
* necessary to put more guard bytes at the end of the window, or
|
|
* to check more often for insufficient lookahead.
|
|
*/
|
|
Assert(scan[2] == match[2], "scan[2]?");
|
|
scan++, match++;
|
|
do {
|
|
} while (*(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
|
|
*(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
|
|
*(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
|
|
*(ushf*)(scan += 2) == *(ushf*)(match += 2) &&
|
|
scan < strend);
|
|
/* The funny "do {}" generates better code on most compilers */
|
|
|
|
/* Here, scan <= window + strstart + 257 */
|
|
Assert(scan <= s->window + (unsigned)(s->window_size - 1),
|
|
"wild scan");
|
|
if (*scan == *match) scan++;
|
|
|
|
len = (MAX_MATCH - 1) - (int)(strend - scan);
|
|
scan = strend - (MAX_MATCH-1);
|
|
|
|
#else /* UNALIGNED_OK */
|
|
|
|
if (match[best_len] != scan_end ||
|
|
match[best_len - 1] != scan_end1 ||
|
|
*match != *scan ||
|
|
*++match != scan[1]) continue;
|
|
|
|
/* The check at best_len - 1 can be removed because it will be made
|
|
* again later. (This heuristic is not always a win.)
|
|
* It is not necessary to compare scan[2] and match[2] since they
|
|
* are always equal when the other bytes match, given that
|
|
* the hash keys are equal and that HASH_BITS >= 8.
|
|
*/
|
|
scan += 2, match++;
|
|
Assert(*scan == *match, "match[2]?");
|
|
|
|
/* We check for insufficient lookahead only every 8th comparison;
|
|
* the 256th check will be made at strstart + 258.
|
|
*/
|
|
do {
|
|
} while (*++scan == *++match && *++scan == *++match &&
|
|
*++scan == *++match && *++scan == *++match &&
|
|
*++scan == *++match && *++scan == *++match &&
|
|
*++scan == *++match && *++scan == *++match &&
|
|
scan < strend);
|
|
|
|
Assert(scan <= s->window + (unsigned)(s->window_size - 1),
|
|
"wild scan");
|
|
|
|
len = MAX_MATCH - (int)(strend - scan);
|
|
scan = strend - MAX_MATCH;
|
|
|
|
#endif /* UNALIGNED_OK */
|
|
|
|
if (len > best_len) {
|
|
s->match_start = cur_match;
|
|
best_len = len;
|
|
if (len >= nice_match) break;
|
|
#ifdef UNALIGNED_OK
|
|
scan_end = *(ushf*)(scan + best_len - 1);
|
|
#else
|
|
scan_end1 = scan[best_len - 1];
|
|
scan_end = scan[best_len];
|
|
#endif
|
|
}
|
|
} while ((cur_match = prev[cur_match & wmask]) > limit
|
|
&& --chain_length != 0);
|
|
|
|
if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
|
|
return s->lookahead;
|
|
}
|
|
|
|
#else /* FASTEST */
|
|
|
|
/* ---------------------------------------------------------------------------
|
|
* Optimized version for FASTEST only
|
|
*/
|
|
local uInt longest_match(deflate_state *s, IPos cur_match) {
|
|
register Bytef *scan = s->window + s->strstart; /* current string */
|
|
register Bytef *match; /* matched string */
|
|
register int len; /* length of current match */
|
|
register Bytef *strend = s->window + s->strstart + MAX_MATCH;
|
|
|
|
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
|
|
* It is easy to get rid of this optimization if necessary.
|
|
*/
|
|
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
|
|
|
|
Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD,
|
|
"need lookahead");
|
|
|
|
Assert(cur_match < s->strstart, "no future");
|
|
|
|
match = s->window + cur_match;
|
|
|
|
/* Return failure if the match length is less than 2:
|
|
*/
|
|
if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
|
|
|
|
/* The check at best_len - 1 can be removed because it will be made
|
|
* again later. (This heuristic is not always a win.)
|
|
* It is not necessary to compare scan[2] and match[2] since they
|
|
* are always equal when the other bytes match, given that
|
|
* the hash keys are equal and that HASH_BITS >= 8.
|
|
*/
|
|
scan += 2, match += 2;
|
|
Assert(*scan == *match, "match[2]?");
|
|
|
|
/* We check for insufficient lookahead only every 8th comparison;
|
|
* the 256th check will be made at strstart + 258.
|
|
*/
|
|
do {
|
|
} while (*++scan == *++match && *++scan == *++match &&
|
|
*++scan == *++match && *++scan == *++match &&
|
|
*++scan == *++match && *++scan == *++match &&
|
|
*++scan == *++match && *++scan == *++match &&
|
|
scan < strend);
|
|
|
|
Assert(scan <= s->window + (unsigned)(s->window_size - 1), "wild scan");
|
|
|
|
len = MAX_MATCH - (int)(strend - scan);
|
|
|
|
if (len < MIN_MATCH) return MIN_MATCH - 1;
|
|
|
|
s->match_start = cur_match;
|
|
return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
|
|
}
|
|
|
|
#endif /* FASTEST */
|
|
|
|
#ifdef ZLIB_DEBUG
|
|
|
|
#define EQUAL 0
|
|
/* result of memcmp for equal strings */
|
|
|
|
/* ===========================================================================
|
|
* Check that the match at match_start is indeed a match.
|
|
*/
|
|
local void check_match(deflate_state *s, IPos start, IPos match, int length) {
|
|
/* check that the match is indeed a match */
|
|
Bytef *back = s->window + (int)match, *here = s->window + start;
|
|
IPos len = length;
|
|
if (match == (IPos)-1) {
|
|
/* match starts one byte before the current window -- just compare the
|
|
subsequent length-1 bytes */
|
|
back++;
|
|
here++;
|
|
len--;
|
|
}
|
|
if (zmemcmp(back, here, len) != EQUAL) {
|
|
fprintf(stderr, " start %u, match %d, length %d\n",
|
|
start, (int)match, length);
|
|
do {
|
|
fprintf(stderr, "(%02x %02x)", *back++, *here++);
|
|
} while (--len != 0);
|
|
z_error("invalid match");
|
|
}
|
|
if (z_verbose > 1) {
|
|
fprintf(stderr,"\\[%d,%d]", start - match, length);
|
|
do { putc(s->window[start++], stderr); } while (--length != 0);
|
|
}
|
|
}
|
|
#else
|
|
# define check_match(s, start, match, length)
|
|
#endif /* ZLIB_DEBUG */
|
|
|
|
/* ===========================================================================
|
|
* Flush the current block, with given end-of-file flag.
|
|
* IN assertion: strstart is set to the end of the current match.
|
|
*/
|
|
#define FLUSH_BLOCK_ONLY(s, last) { \
|
|
_tr_flush_block(s, (s->block_start >= 0L ? \
|
|
(charf *)&s->window[(unsigned)s->block_start] : \
|
|
(charf *)Z_NULL), \
|
|
(ulg)((long)s->strstart - s->block_start), \
|
|
(last)); \
|
|
s->block_start = s->strstart; \
|
|
flush_pending(s->strm); \
|
|
Tracev((stderr,"[FLUSH]")); \
|
|
}
|
|
|
|
/* Same but force premature exit if necessary. */
|
|
#define FLUSH_BLOCK(s, last) { \
|
|
FLUSH_BLOCK_ONLY(s, last); \
|
|
if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
|
|
}
|
|
|
|
/* Maximum stored block length in deflate format (not including header). */
|
|
#define MAX_STORED 65535
|
|
|
|
/* Minimum of a and b. */
|
|
#define MIN(a, b) ((a) > (b) ? (b) : (a))
|
|
|
|
/* ===========================================================================
|
|
* Copy without compression as much as possible from the input stream, return
|
|
* the current block state.
|
|
*
|
|
* In case deflateParams() is used to later switch to a non-zero compression
|
|
* level, s->matches (otherwise unused when storing) keeps track of the number
|
|
* of hash table slides to perform. If s->matches is 1, then one hash table
|
|
* slide will be done when switching. If s->matches is 2, the maximum value
|
|
* allowed here, then the hash table will be cleared, since two or more slides
|
|
* is the same as a clear.
|
|
*
|
|
* deflate_stored() is written to minimize the number of times an input byte is
|
|
* copied. It is most efficient with large input and output buffers, which
|
|
* maximizes the opportunities to have a single copy from next_in to next_out.
|
|
*/
|
|
local block_state deflate_stored(deflate_state *s, int flush) {
|
|
/* Smallest worthy block size when not flushing or finishing. By default
|
|
* this is 32K. This can be as small as 507 bytes for memLevel == 1. For
|
|
* large input and output buffers, the stored block size will be larger.
|
|
*/
|
|
unsigned min_block = MIN(s->pending_buf_size - 5, s->w_size);
|
|
|
|
/* Copy as many min_block or larger stored blocks directly to next_out as
|
|
* possible. If flushing, copy the remaining available input to next_out as
|
|
* stored blocks, if there is enough space.
|
|
*/
|
|
unsigned len, left, have, last = 0;
|
|
unsigned used = s->strm->avail_in;
|
|
do {
|
|
/* Set len to the maximum size block that we can copy directly with the
|
|
* available input data and output space. Set left to how much of that
|
|
* would be copied from what's left in the window.
|
|
*/
|
|
len = MAX_STORED; /* maximum deflate stored block length */
|
|
have = (s->bi_valid + 42) >> 3; /* number of header bytes */
|
|
if (s->strm->avail_out < have) /* need room for header */
|
|
break;
|
|
/* maximum stored block length that will fit in avail_out: */
|
|
have = s->strm->avail_out - have;
|
|
left = s->strstart - s->block_start; /* bytes left in window */
|
|
if (len > (ulg)left + s->strm->avail_in)
|
|
len = left + s->strm->avail_in; /* limit len to the input */
|
|
if (len > have)
|
|
len = have; /* limit len to the output */
|
|
|
|
/* If the stored block would be less than min_block in length, or if
|
|
* unable to copy all of the available input when flushing, then try
|
|
* copying to the window and the pending buffer instead. Also don't
|
|
* write an empty block when flushing -- deflate() does that.
|
|
*/
|
|
if (len < min_block && ((len == 0 && flush != Z_FINISH) ||
|
|
flush == Z_NO_FLUSH ||
|
|
len != left + s->strm->avail_in))
|
|
break;
|
|
|
|
/* Make a dummy stored block in pending to get the header bytes,
|
|
* including any pending bits. This also updates the debugging counts.
|
|
*/
|
|
last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0;
|
|
_tr_stored_block(s, (char *)0, 0L, last);
|
|
|
|
/* Replace the lengths in the dummy stored block with len. */
|
|
s->pending_buf[s->pending - 4] = len;
|
|
s->pending_buf[s->pending - 3] = len >> 8;
|
|
s->pending_buf[s->pending - 2] = ~len;
|
|
s->pending_buf[s->pending - 1] = ~len >> 8;
|
|
|
|
/* Write the stored block header bytes. */
|
|
flush_pending(s->strm);
|
|
|
|
#ifdef ZLIB_DEBUG
|
|
/* Update debugging counts for the data about to be copied. */
|
|
s->compressed_len += len << 3;
|
|
s->bits_sent += len << 3;
|
|
#endif
|
|
|
|
/* Copy uncompressed bytes from the window to next_out. */
|
|
if (left) {
|
|
if (left > len)
|
|
left = len;
|
|
zmemcpy(s->strm->next_out, s->window + s->block_start, left);
|
|
s->strm->next_out += left;
|
|
s->strm->avail_out -= left;
|
|
s->strm->total_out += left;
|
|
s->block_start += left;
|
|
len -= left;
|
|
}
|
|
|
|
/* Copy uncompressed bytes directly from next_in to next_out, updating
|
|
* the check value.
|
|
*/
|
|
if (len) {
|
|
read_buf(s->strm, s->strm->next_out, len);
|
|
s->strm->next_out += len;
|
|
s->strm->avail_out -= len;
|
|
s->strm->total_out += len;
|
|
}
|
|
} while (last == 0);
|
|
|
|
/* Update the sliding window with the last s->w_size bytes of the copied
|
|
* data, or append all of the copied data to the existing window if less
|
|
* than s->w_size bytes were copied. Also update the number of bytes to
|
|
* insert in the hash tables, in the event that deflateParams() switches to
|
|
* a non-zero compression level.
|
|
*/
|
|
used -= s->strm->avail_in; /* number of input bytes directly copied */
|
|
if (used) {
|
|
/* If any input was used, then no unused input remains in the window,
|
|
* therefore s->block_start == s->strstart.
|
|
*/
|
|
if (used >= s->w_size) { /* supplant the previous history */
|
|
s->matches = 2; /* clear hash */
|
|
zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size);
|
|
s->strstart = s->w_size;
|
|
s->insert = s->strstart;
|
|
}
|
|
else {
|
|
if (s->window_size - s->strstart <= used) {
|
|
/* Slide the window down. */
|
|
s->strstart -= s->w_size;
|
|
zmemcpy(s->window, s->window + s->w_size, s->strstart);
|
|
if (s->matches < 2)
|
|
s->matches++; /* add a pending slide_hash() */
|
|
if (s->insert > s->strstart)
|
|
s->insert = s->strstart;
|
|
}
|
|
zmemcpy(s->window + s->strstart, s->strm->next_in - used, used);
|
|
s->strstart += used;
|
|
s->insert += MIN(used, s->w_size - s->insert);
|
|
}
|
|
s->block_start = s->strstart;
|
|
}
|
|
if (s->high_water < s->strstart)
|
|
s->high_water = s->strstart;
|
|
|
|
/* If the last block was written to next_out, then done. */
|
|
if (last)
|
|
return finish_done;
|
|
|
|
/* If flushing and all input has been consumed, then done. */
|
|
if (flush != Z_NO_FLUSH && flush != Z_FINISH &&
|
|
s->strm->avail_in == 0 && (long)s->strstart == s->block_start)
|
|
return block_done;
|
|
|
|
/* Fill the window with any remaining input. */
|
|
have = s->window_size - s->strstart;
|
|
if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) {
|
|
/* Slide the window down. */
|
|
s->block_start -= s->w_size;
|
|
s->strstart -= s->w_size;
|
|
zmemcpy(s->window, s->window + s->w_size, s->strstart);
|
|
if (s->matches < 2)
|
|
s->matches++; /* add a pending slide_hash() */
|
|
have += s->w_size; /* more space now */
|
|
if (s->insert > s->strstart)
|
|
s->insert = s->strstart;
|
|
}
|
|
if (have > s->strm->avail_in)
|
|
have = s->strm->avail_in;
|
|
if (have) {
|
|
read_buf(s->strm, s->window + s->strstart, have);
|
|
s->strstart += have;
|
|
s->insert += MIN(have, s->w_size - s->insert);
|
|
}
|
|
if (s->high_water < s->strstart)
|
|
s->high_water = s->strstart;
|
|
|
|
/* There was not enough avail_out to write a complete worthy or flushed
|
|
* stored block to next_out. Write a stored block to pending instead, if we
|
|
* have enough input for a worthy block, or if flushing and there is enough
|
|
* room for the remaining input as a stored block in the pending buffer.
|
|
*/
|
|
have = (s->bi_valid + 42) >> 3; /* number of header bytes */
|
|
/* maximum stored block length that will fit in pending: */
|
|
have = MIN(s->pending_buf_size - have, MAX_STORED);
|
|
min_block = MIN(have, s->w_size);
|
|
left = s->strstart - s->block_start;
|
|
if (left >= min_block ||
|
|
((left || flush == Z_FINISH) && flush != Z_NO_FLUSH &&
|
|
s->strm->avail_in == 0 && left <= have)) {
|
|
len = MIN(left, have);
|
|
last = flush == Z_FINISH && s->strm->avail_in == 0 &&
|
|
len == left ? 1 : 0;
|
|
_tr_stored_block(s, (charf *)s->window + s->block_start, len, last);
|
|
s->block_start += len;
|
|
flush_pending(s->strm);
|
|
}
|
|
|
|
/* We've done all we can with the available input and output. */
|
|
return last ? finish_started : need_more;
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* Compress as much as possible from the input stream, return the current
|
|
* block state.
|
|
* This function does not perform lazy evaluation of matches and inserts
|
|
* new strings in the dictionary only for unmatched strings or for short
|
|
* matches. It is used only for the fast compression options.
|
|
*/
|
|
local block_state deflate_fast(deflate_state *s, int flush) {
|
|
IPos hash_head; /* head of the hash chain */
|
|
int bflush; /* set if current block must be flushed */
|
|
|
|
for (;;) {
|
|
/* Make sure that we always have enough lookahead, except
|
|
* at the end of the input file. We need MAX_MATCH bytes
|
|
* for the next match, plus MIN_MATCH bytes to insert the
|
|
* string following the next match.
|
|
*/
|
|
if (s->lookahead < MIN_LOOKAHEAD) {
|
|
fill_window(s);
|
|
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
|
|
return need_more;
|
|
}
|
|
if (s->lookahead == 0) break; /* flush the current block */
|
|
}
|
|
|
|
/* Insert the string window[strstart .. strstart + 2] in the
|
|
* dictionary, and set hash_head to the head of the hash chain:
|
|
*/
|
|
hash_head = NIL;
|
|
if (s->lookahead >= MIN_MATCH) {
|
|
INSERT_STRING(s, s->strstart, hash_head);
|
|
}
|
|
|
|
/* Find the longest match, discarding those <= prev_length.
|
|
* At this point we have always match_length < MIN_MATCH
|
|
*/
|
|
if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
|
|
/* To simplify the code, we prevent matches with the string
|
|
* of window index 0 (in particular we have to avoid a match
|
|
* of the string with itself at the start of the input file).
|
|
*/
|
|
s->match_length = longest_match (s, hash_head);
|
|
/* longest_match() sets match_start */
|
|
}
|
|
if (s->match_length >= MIN_MATCH) {
|
|
check_match(s, s->strstart, s->match_start, s->match_length);
|
|
|
|
_tr_tally_dist(s, s->strstart - s->match_start,
|
|
s->match_length - MIN_MATCH, bflush);
|
|
|
|
s->lookahead -= s->match_length;
|
|
|
|
/* Insert new strings in the hash table only if the match length
|
|
* is not too large. This saves time but degrades compression.
|
|
*/
|
|
#ifndef FASTEST
|
|
if (s->match_length <= s->max_insert_length &&
|
|
s->lookahead >= MIN_MATCH) {
|
|
s->match_length--; /* string at strstart already in table */
|
|
do {
|
|
s->strstart++;
|
|
INSERT_STRING(s, s->strstart, hash_head);
|
|
/* strstart never exceeds WSIZE-MAX_MATCH, so there are
|
|
* always MIN_MATCH bytes ahead.
|
|
*/
|
|
} while (--s->match_length != 0);
|
|
s->strstart++;
|
|
} else
|
|
#endif
|
|
{
|
|
s->strstart += s->match_length;
|
|
s->match_length = 0;
|
|
s->ins_h = s->window[s->strstart];
|
|
UPDATE_HASH(s, s->ins_h, s->window[s->strstart + 1]);
|
|
#if MIN_MATCH != 3
|
|
Call UPDATE_HASH() MIN_MATCH-3 more times
|
|
#endif
|
|
/* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
|
|
* matter since it will be recomputed at next deflate call.
|
|
*/
|
|
}
|
|
} else {
|
|
/* No match, output a literal byte */
|
|
Tracevv((stderr,"%c", s->window[s->strstart]));
|
|
_tr_tally_lit(s, s->window[s->strstart], bflush);
|
|
s->lookahead--;
|
|
s->strstart++;
|
|
}
|
|
if (bflush) FLUSH_BLOCK(s, 0);
|
|
}
|
|
s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
|
|
if (flush == Z_FINISH) {
|
|
FLUSH_BLOCK(s, 1);
|
|
return finish_done;
|
|
}
|
|
if (s->sym_next)
|
|
FLUSH_BLOCK(s, 0);
|
|
return block_done;
|
|
}
|
|
|
|
#ifndef FASTEST
|
|
/* ===========================================================================
|
|
* Same as above, but achieves better compression. We use a lazy
|
|
* evaluation for matches: a match is finally adopted only if there is
|
|
* no better match at the next window position.
|
|
*/
|
|
local block_state deflate_slow(deflate_state *s, int flush) {
|
|
IPos hash_head; /* head of hash chain */
|
|
int bflush; /* set if current block must be flushed */
|
|
|
|
/* Process the input block. */
|
|
for (;;) {
|
|
/* Make sure that we always have enough lookahead, except
|
|
* at the end of the input file. We need MAX_MATCH bytes
|
|
* for the next match, plus MIN_MATCH bytes to insert the
|
|
* string following the next match.
|
|
*/
|
|
if (s->lookahead < MIN_LOOKAHEAD) {
|
|
fill_window(s);
|
|
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
|
|
return need_more;
|
|
}
|
|
if (s->lookahead == 0) break; /* flush the current block */
|
|
}
|
|
|
|
/* Insert the string window[strstart .. strstart + 2] in the
|
|
* dictionary, and set hash_head to the head of the hash chain:
|
|
*/
|
|
hash_head = NIL;
|
|
if (s->lookahead >= MIN_MATCH) {
|
|
INSERT_STRING(s, s->strstart, hash_head);
|
|
}
|
|
|
|
/* Find the longest match, discarding those <= prev_length.
|
|
*/
|
|
s->prev_length = s->match_length, s->prev_match = s->match_start;
|
|
s->match_length = MIN_MATCH-1;
|
|
|
|
if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
|
|
s->strstart - hash_head <= MAX_DIST(s)) {
|
|
/* To simplify the code, we prevent matches with the string
|
|
* of window index 0 (in particular we have to avoid a match
|
|
* of the string with itself at the start of the input file).
|
|
*/
|
|
s->match_length = longest_match (s, hash_head);
|
|
/* longest_match() sets match_start */
|
|
|
|
if (s->match_length <= 5 && (s->strategy == Z_FILTERED
|
|
#if TOO_FAR <= 32767
|
|
|| (s->match_length == MIN_MATCH &&
|
|
s->strstart - s->match_start > TOO_FAR)
|
|
#endif
|
|
)) {
|
|
|
|
/* If prev_match is also MIN_MATCH, match_start is garbage
|
|
* but we will ignore the current match anyway.
|
|
*/
|
|
s->match_length = MIN_MATCH-1;
|
|
}
|
|
}
|
|
/* If there was a match at the previous step and the current
|
|
* match is not better, output the previous match:
|
|
*/
|
|
if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
|
|
uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
|
|
/* Do not insert strings in hash table beyond this. */
|
|
|
|
check_match(s, s->strstart - 1, s->prev_match, s->prev_length);
|
|
|
|
_tr_tally_dist(s, s->strstart - 1 - s->prev_match,
|
|
s->prev_length - MIN_MATCH, bflush);
|
|
|
|
/* Insert in hash table all strings up to the end of the match.
|
|
* strstart - 1 and strstart are already inserted. If there is not
|
|
* enough lookahead, the last two strings are not inserted in
|
|
* the hash table.
|
|
*/
|
|
s->lookahead -= s->prev_length - 1;
|
|
s->prev_length -= 2;
|
|
do {
|
|
if (++s->strstart <= max_insert) {
|
|
INSERT_STRING(s, s->strstart, hash_head);
|
|
}
|
|
} while (--s->prev_length != 0);
|
|
s->match_available = 0;
|
|
s->match_length = MIN_MATCH-1;
|
|
s->strstart++;
|
|
|
|
if (bflush) FLUSH_BLOCK(s, 0);
|
|
|
|
} else if (s->match_available) {
|
|
/* If there was no match at the previous position, output a
|
|
* single literal. If there was a match but the current match
|
|
* is longer, truncate the previous match to a single literal.
|
|
*/
|
|
Tracevv((stderr,"%c", s->window[s->strstart - 1]));
|
|
_tr_tally_lit(s, s->window[s->strstart - 1], bflush);
|
|
if (bflush) {
|
|
FLUSH_BLOCK_ONLY(s, 0);
|
|
}
|
|
s->strstart++;
|
|
s->lookahead--;
|
|
if (s->strm->avail_out == 0) return need_more;
|
|
} else {
|
|
/* There is no previous match to compare with, wait for
|
|
* the next step to decide.
|
|
*/
|
|
s->match_available = 1;
|
|
s->strstart++;
|
|
s->lookahead--;
|
|
}
|
|
}
|
|
Assert (flush != Z_NO_FLUSH, "no flush?");
|
|
if (s->match_available) {
|
|
Tracevv((stderr,"%c", s->window[s->strstart - 1]));
|
|
_tr_tally_lit(s, s->window[s->strstart - 1], bflush);
|
|
s->match_available = 0;
|
|
}
|
|
s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1;
|
|
if (flush == Z_FINISH) {
|
|
FLUSH_BLOCK(s, 1);
|
|
return finish_done;
|
|
}
|
|
if (s->sym_next)
|
|
FLUSH_BLOCK(s, 0);
|
|
return block_done;
|
|
}
|
|
#endif /* FASTEST */
|
|
|
|
/* ===========================================================================
|
|
* For Z_RLE, simply look for runs of bytes, generate matches only of distance
|
|
* one. Do not maintain a hash table. (It will be regenerated if this run of
|
|
* deflate switches away from Z_RLE.)
|
|
*/
|
|
local block_state deflate_rle(deflate_state *s, int flush) {
|
|
int bflush; /* set if current block must be flushed */
|
|
uInt prev; /* byte at distance one to match */
|
|
Bytef *scan, *strend; /* scan goes up to strend for length of run */
|
|
|
|
for (;;) {
|
|
/* Make sure that we always have enough lookahead, except
|
|
* at the end of the input file. We need MAX_MATCH bytes
|
|
* for the longest run, plus one for the unrolled loop.
|
|
*/
|
|
if (s->lookahead <= MAX_MATCH) {
|
|
fill_window(s);
|
|
if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) {
|
|
return need_more;
|
|
}
|
|
if (s->lookahead == 0) break; /* flush the current block */
|
|
}
|
|
|
|
/* See how many times the previous byte repeats */
|
|
s->match_length = 0;
|
|
if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
|
|
scan = s->window + s->strstart - 1;
|
|
prev = *scan;
|
|
if (prev == *++scan && prev == *++scan && prev == *++scan) {
|
|
strend = s->window + s->strstart + MAX_MATCH;
|
|
do {
|
|
} while (prev == *++scan && prev == *++scan &&
|
|
prev == *++scan && prev == *++scan &&
|
|
prev == *++scan && prev == *++scan &&
|
|
prev == *++scan && prev == *++scan &&
|
|
scan < strend);
|
|
s->match_length = MAX_MATCH - (uInt)(strend - scan);
|
|
if (s->match_length > s->lookahead)
|
|
s->match_length = s->lookahead;
|
|
}
|
|
Assert(scan <= s->window + (uInt)(s->window_size - 1),
|
|
"wild scan");
|
|
}
|
|
|
|
/* Emit match if have run of MIN_MATCH or longer, else emit literal */
|
|
if (s->match_length >= MIN_MATCH) {
|
|
check_match(s, s->strstart, s->strstart - 1, s->match_length);
|
|
|
|
_tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
|
|
|
|
s->lookahead -= s->match_length;
|
|
s->strstart += s->match_length;
|
|
s->match_length = 0;
|
|
} else {
|
|
/* No match, output a literal byte */
|
|
Tracevv((stderr,"%c", s->window[s->strstart]));
|
|
_tr_tally_lit(s, s->window[s->strstart], bflush);
|
|
s->lookahead--;
|
|
s->strstart++;
|
|
}
|
|
if (bflush) FLUSH_BLOCK(s, 0);
|
|
}
|
|
s->insert = 0;
|
|
if (flush == Z_FINISH) {
|
|
FLUSH_BLOCK(s, 1);
|
|
return finish_done;
|
|
}
|
|
if (s->sym_next)
|
|
FLUSH_BLOCK(s, 0);
|
|
return block_done;
|
|
}
|
|
|
|
/* ===========================================================================
|
|
* For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
|
|
* (It will be regenerated if this run of deflate switches away from Huffman.)
|
|
*/
|
|
local block_state deflate_huff(deflate_state *s, int flush) {
|
|
int bflush; /* set if current block must be flushed */
|
|
|
|
for (;;) {
|
|
/* Make sure that we have a literal to write. */
|
|
if (s->lookahead == 0) {
|
|
fill_window(s);
|
|
if (s->lookahead == 0) {
|
|
if (flush == Z_NO_FLUSH)
|
|
return need_more;
|
|
break; /* flush the current block */
|
|
}
|
|
}
|
|
|
|
/* Output a literal byte */
|
|
s->match_length = 0;
|
|
Tracevv((stderr,"%c", s->window[s->strstart]));
|
|
_tr_tally_lit(s, s->window[s->strstart], bflush);
|
|
s->lookahead--;
|
|
s->strstart++;
|
|
if (bflush) FLUSH_BLOCK(s, 0);
|
|
}
|
|
s->insert = 0;
|
|
if (flush == Z_FINISH) {
|
|
FLUSH_BLOCK(s, 1);
|
|
return finish_done;
|
|
}
|
|
if (s->sym_next)
|
|
FLUSH_BLOCK(s, 0);
|
|
return block_done;
|
|
}
|