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/* deflate.c -- compress data using the deflation algorithm |
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* Copyright (C) 1995-2026 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 at https://datatracker.ietf.org/doc/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 1.3.2 Copyright 1995-2026 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(s->head, (unsigned)(s->hash_size - 1)*sizeof(*s->head)); \ |
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s->slid = 0; \ |
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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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#ifndef FASTEST |
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n = wsize; |
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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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s->slid = 1; |
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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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256
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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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261
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262
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/* Deal with !@#$% 64K limit: */ |
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#ifdef _MSC_VER |
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#pragma warning(push) |
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265
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#pragma warning(disable: 4127) |
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266
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#endif |
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267
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if (sizeof(int) <= 2) { |
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268
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#ifdef _MSC_VER |
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#pragma warning(pop) |
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270
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#endif |
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if (more == 0 && s->strstart == 0 && s->lookahead == 0) { |
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272
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more = wsize; |
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273
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274
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} else if (more == (unsigned)(-1)) { |
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275
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/* Very unlikely, but possible on 16 bit machine if |
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276
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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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280
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} |
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281
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282
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/* If the window is almost full and there is insufficient lookahead, |
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283
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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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285
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if (s->strstart >= wsize + MAX_DIST(s)) { |
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286
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287
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zmemcpy(s->window, s->window + wsize, (unsigned)wsize - more); |
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288
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s->match_start -= wsize; |
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289
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s->strstart -= wsize; /* we now have strstart >= MAX_DIST */ |
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290
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s->block_start -= (long) wsize; |
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291
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if (s->insert > s->strstart) |
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292
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s->insert = s->strstart; |
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293
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slide_hash(s); |
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294
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more += wsize; |
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295
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} |
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296
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if (s->strm->avail_in == 0) break; |
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297
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|
298
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/* If there was no sliding: |
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299
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* strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 && |
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300
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* more == window_size - lookahead - strstart |
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301
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* => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1) |
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302
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* => more >= window_size - 2*WSIZE + 2 |
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303
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* In the BIG_MEM or MMAP case (not yet supported), |
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304
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* window_size == input_size + MIN_LOOKAHEAD && |
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305
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* strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD. |
|
306
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* Otherwise, window_size == 2*WSIZE so more >= 2. |
|
307
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* If there was sliding, more >= WSIZE. So in all cases, more >= 2. |
|
308
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*/ |
|
309
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Assert(more >= 2, "more < 2"); |
|
310
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|
311
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n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more); |
|
312
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s->lookahead += n; |
|
313
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|
|
314
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/* Initialize the hash value now that we have some input: */ |
|
315
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if (s->lookahead + s->insert >= MIN_MATCH) { |
|
316
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uInt str = s->strstart - s->insert; |
|
317
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s->ins_h = s->window[str]; |
|
318
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UPDATE_HASH(s, s->ins_h, s->window[str + 1]); |
|
319
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#if MIN_MATCH != 3 |
|
320
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Call UPDATE_HASH() MIN_MATCH-3 more times |
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321
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#endif |
|
322
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while (s->insert) { |
|
323
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UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); |
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324
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#ifndef FASTEST |
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325
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s->prev[str & s->w_mask] = s->head[s->ins_h]; |
|
326
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#endif |
|
327
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s->head[s->ins_h] = (Pos)str; |
|
328
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str++; |
|
329
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s->insert--; |
|
330
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if (s->lookahead + s->insert < MIN_MATCH) |
|
331
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break; |
|
332
|
} |
|
333
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} |
|
334
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/* If the whole input has less than MIN_MATCH bytes, ins_h is garbage, |
|
335
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* but this is not important since only literal bytes will be emitted. |
|
336
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*/ |
|
337
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|
|
338
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} while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0); |
|
339
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|
|
340
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/* If the WIN_INIT bytes after the end of the current data have never been |
|
341
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* written, then zero those bytes in order to avoid memory check reports of |
|
342
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* the use of uninitialized (or uninitialised as Julian writes) bytes by |
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343
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* the longest match routines. Update the high water mark for the next |
|
344
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* time through here. WIN_INIT is set to MAX_MATCH since the longest match |
|
345
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* routines allow scanning to strstart + MAX_MATCH, ignoring lookahead. |
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346
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*/ |
|
347
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if (s->high_water < s->window_size) { |
|
348
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ulg curr = s->strstart + (ulg)(s->lookahead); |
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349
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ulg init; |
|
350
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|
|
351
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if (s->high_water < curr) { |
|
352
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/* Previous high water mark below current data -- zero WIN_INIT |
|
353
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* bytes or up to end of window, whichever is less. |
|
354
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*/ |
|
355
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init = s->window_size - curr; |
|
356
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if (init > WIN_INIT) |
|
357
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init = WIN_INIT; |
|
358
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zmemzero(s->window + curr, (unsigned)init); |
|
359
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s->high_water = curr + init; |
|
360
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} |
|
361
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else if (s->high_water < (ulg)curr + WIN_INIT) { |
|
362
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/* High water mark at or above current data, but below current data |
|
363
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* plus WIN_INIT -- zero out to current data plus WIN_INIT, or up |
|
364
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* to end of window, whichever is less. |
|
365
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*/ |
|
366
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init = (ulg)curr + WIN_INIT - s->high_water; |
|
367
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if (init > s->window_size - s->high_water) |
|
368
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init = s->window_size - s->high_water; |
|
369
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zmemzero(s->window + s->high_water, (unsigned)init); |
|
370
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s->high_water += init; |
|
371
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} |
|
372
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} |
|
373
|
|
|
374
|
Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, |
|
375
|
"not enough room for search"); |
|
376
|
} |
|
377
|
|
|
378
|
/* ========================================================================= */ |
|
379
|
int ZEXPORT deflateInit_(z_streamp strm, int level, const char *version, |
|
380
|
int stream_size) { |
|
381
|
return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL, |
|
382
|
Z_DEFAULT_STRATEGY, version, stream_size); |
|
383
|
/* To do: ignore strm->next_in if we use it as window */ |
|
384
|
} |
|
385
|
|
|
386
|
/* ========================================================================= */ |
|
387
|
int ZEXPORT deflateInit2_(z_streamp strm, int level, int method, |
|
388
|
int windowBits, int memLevel, int strategy, |
|
389
|
const char *version, int stream_size) { |
|
390
|
deflate_state *s; |
|
391
|
int wrap = 1; |
|
392
|
static const char my_version[] = ZLIB_VERSION; |
|
393
|
|
|
394
|
if (version == Z_NULL || version[0] != my_version[0] || |
|
395
|
stream_size != sizeof(z_stream)) { |
|
396
|
return Z_VERSION_ERROR; |
|
397
|
} |
|
398
|
if (strm == Z_NULL) return Z_STREAM_ERROR; |
|
399
|
|
|
400
|
strm->msg = Z_NULL; |
|
401
|
if (strm->zalloc == (alloc_func)0) { |
|
402
|
#ifdef Z_SOLO |
|
403
|
return Z_STREAM_ERROR; |
|
404
|
#else |
|
405
|
strm->zalloc = zcalloc; |
|
406
|
strm->opaque = (voidpf)0; |
|
407
|
#endif |
|
408
|
} |
|
409
|
if (strm->zfree == (free_func)0) |
|
410
|
#ifdef Z_SOLO |
|
411
|
return Z_STREAM_ERROR; |
|
412
|
#else |
|
413
|
strm->zfree = zcfree; |
|
414
|
#endif |
|
415
|
|
|
416
|
#ifdef FASTEST |
|
417
|
if (level != 0) level = 1; |
|
418
|
#else |
|
419
|
if (level == Z_DEFAULT_COMPRESSION) level = 6; |
|
420
|
#endif |
|
421
|
|
|
422
|
if (windowBits < 0) { /* suppress zlib wrapper */ |
|
423
|
wrap = 0; |
|
424
|
if (windowBits < -15) |
|
425
|
return Z_STREAM_ERROR; |
|
426
|
windowBits = -windowBits; |
|
427
|
} |
|
428
|
#ifdef GZIP |
|
429
|
else if (windowBits > 15) { |
|
430
|
wrap = 2; /* write gzip wrapper instead */ |
|
431
|
windowBits -= 16; |
|
432
|
} |
|
433
|
#endif |
|
434
|
if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED || |
|
435
|
windowBits < 8 || windowBits > 15 || level < 0 || level > 9 || |
|
436
|
strategy < 0 || strategy > Z_FIXED || (windowBits == 8 && wrap != 1)) { |
|
437
|
return Z_STREAM_ERROR; |
|
438
|
} |
|
439
|
if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */ |
|
440
|
s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state)); |
|
441
|
if (s == Z_NULL) return Z_MEM_ERROR; |
|
442
|
zmemzero(s, sizeof(deflate_state)); |
|
443
|
strm->state = (struct internal_state FAR *)s; |
|
444
|
s->strm = strm; |
|
445
|
s->status = INIT_STATE; /* to pass state test in deflateReset() */ |
|
446
|
|
|
447
|
s->wrap = wrap; |
|
448
|
s->gzhead = Z_NULL; |
|
449
|
s->w_bits = (uInt)windowBits; |
|
450
|
s->w_size = 1 << s->w_bits; |
|
451
|
s->w_mask = s->w_size - 1; |
|
452
|
|
|
453
|
s->hash_bits = (uInt)memLevel + 7; |
|
454
|
s->hash_size = 1 << s->hash_bits; |
|
455
|
s->hash_mask = s->hash_size - 1; |
|
456
|
s->hash_shift = ((s->hash_bits + MIN_MATCH-1) / MIN_MATCH); |
|
457
|
|
|
458
|
s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte)); |
|
459
|
s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos)); |
|
460
|
s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos)); |
|
461
|
|
|
462
|
s->high_water = 0; /* nothing written to s->window yet */ |
|
463
|
|
|
464
|
s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */ |
|
465
|
|
|
466
|
/* We overlay pending_buf and sym_buf. This works since the average size |
|
467
|
* for length/distance pairs over any compressed block is assured to be 31 |
|
468
|
* bits or less. |
|
469
|
* |
|
470
|
* Analysis: The longest fixed codes are a length code of 8 bits plus 5 |
|
471
|
* extra bits, for lengths 131 to 257. The longest fixed distance codes are |
|
472
|
* 5 bits plus 13 extra bits, for distances 16385 to 32768. The longest |
|
473
|
* possible fixed-codes length/distance pair is then 31 bits total. |
|
474
|
* |
|
475
|
* sym_buf starts one-fourth of the way into pending_buf. So there are |
|
476
|
* three bytes in sym_buf for every four bytes in pending_buf. Each symbol |
|
477
|
* in sym_buf is three bytes -- two for the distance and one for the |
|
478
|
* literal/length. As each symbol is consumed, the pointer to the next |
|
479
|
* sym_buf value to read moves forward three bytes. From that symbol, up to |
|
480
|
* 31 bits are written to pending_buf. The closest the written pending_buf |
|
481
|
* bits gets to the next sym_buf symbol to read is just before the last |
|
482
|
* code is written. At that time, 31*(n - 2) bits have been written, just |
|
483
|
* after 24*(n - 2) bits have been consumed from sym_buf. sym_buf starts at |
|
484
|
* 8*n bits into pending_buf. (Note that the symbol buffer fills when n - 1 |
|
485
|
* symbols are written.) The closest the writing gets to what is unread is |
|
486
|
* then n + 14 bits. Here n is lit_bufsize, which is 16384 by default, and |
|
487
|
* can range from 128 to 32768. |
|
488
|
* |
|
489
|
* Therefore, at a minimum, there are 142 bits of space between what is |
|
490
|
* written and what is read in the overlain buffers, so the symbols cannot |
|
491
|
* be overwritten by the compressed data. That space is actually 139 bits, |
|
492
|
* due to the three-bit fixed-code block header. |
|
493
|
* |
|
494
|
* That covers the case where either Z_FIXED is specified, forcing fixed |
|
495
|
* codes, or when the use of fixed codes is chosen, because that choice |
|
496
|
* results in a smaller compressed block than dynamic codes. That latter |
|
497
|
* condition then assures that the above analysis also covers all dynamic |
|
498
|
* blocks. A dynamic-code block will only be chosen to be emitted if it has |
|
499
|
* fewer bits than a fixed-code block would for the same set of symbols. |
|
500
|
* Therefore its average symbol length is assured to be less than 31. So |
|
501
|
* the compressed data for a dynamic block also cannot overwrite the |
|
502
|
* symbols from which it is being constructed. |
|
503
|
*/ |
|
504
|
|
|
505
|
s->pending_buf = (uchf *) ZALLOC(strm, s->lit_bufsize, LIT_BUFS); |
|
506
|
s->pending_buf_size = (ulg)s->lit_bufsize * 4; |
|
507
|
|
|
508
|
if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL || |
|
509
|
s->pending_buf == Z_NULL) { |
|
510
|
s->status = FINISH_STATE; |
|
511
|
strm->msg = ERR_MSG(Z_MEM_ERROR); |
|
512
|
deflateEnd (strm); |
|
513
|
return Z_MEM_ERROR; |
|
514
|
} |
|
515
|
#ifdef LIT_MEM |
|
516
|
s->d_buf = (ushf *)(s->pending_buf + (s->lit_bufsize << 1)); |
|
517
|
s->l_buf = s->pending_buf + (s->lit_bufsize << 2); |
|
518
|
s->sym_end = s->lit_bufsize - 1; |
|
519
|
#else |
|
520
|
s->sym_buf = s->pending_buf + s->lit_bufsize; |
|
521
|
s->sym_end = (s->lit_bufsize - 1) * 3; |
|
522
|
#endif |
|
523
|
/* We avoid equality with lit_bufsize*3 because of wraparound at 64K |
|
524
|
* on 16 bit machines and because stored blocks are restricted to |
|
525
|
* 64K-1 bytes. |
|
526
|
*/ |
|
527
|
|
|
528
|
s->level = level; |
|
529
|
s->strategy = strategy; |
|
530
|
s->method = (Byte)method; |
|
531
|
|
|
532
|
return deflateReset(strm); |
|
533
|
} |
|
534
|
|
|
535
|
/* ========================================================================= |
|
536
|
* Check for a valid deflate stream state. Return 0 if ok, 1 if not. |
|
537
|
*/ |
|
538
|
local int deflateStateCheck(z_streamp strm) { |
|
539
|
deflate_state *s; |
|
540
|
if (strm == Z_NULL || |
|
541
|
strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) |
|
542
|
return 1; |
|
543
|
s = strm->state; |
|
544
|
if (s == Z_NULL || s->strm != strm || (s->status != INIT_STATE && |
|
545
|
#ifdef GZIP |
|
546
|
s->status != GZIP_STATE && |
|
547
|
#endif |
|
548
|
s->status != EXTRA_STATE && |
|
549
|
s->status != NAME_STATE && |
|
550
|
s->status != COMMENT_STATE && |
|
551
|
s->status != HCRC_STATE && |
|
552
|
s->status != BUSY_STATE && |
|
553
|
s->status != FINISH_STATE)) |
|
554
|
return 1; |
|
555
|
return 0; |
|
556
|
} |
|
557
|
|
|
558
|
/* ========================================================================= */ |
|
559
|
int ZEXPORT deflateSetDictionary(z_streamp strm, const Bytef *dictionary, |
|
560
|
uInt dictLength) { |
|
561
|
deflate_state *s; |
|
562
|
uInt str, n; |
|
563
|
int wrap; |
|
564
|
unsigned avail; |
|
565
|
z_const unsigned char *next; |
|
566
|
|
|
567
|
if (deflateStateCheck(strm) || dictionary == Z_NULL) |
|
568
|
return Z_STREAM_ERROR; |
|
569
|
s = strm->state; |
|
570
|
wrap = s->wrap; |
|
571
|
if (wrap == 2 || (wrap == 1 && s->status != INIT_STATE) || s->lookahead) |
|
572
|
return Z_STREAM_ERROR; |
|
573
|
|
|
574
|
/* when using zlib wrappers, compute Adler-32 for provided dictionary */ |
|
575
|
if (wrap == 1) |
|
576
|
strm->adler = adler32(strm->adler, dictionary, dictLength); |
|
577
|
s->wrap = 0; /* avoid computing Adler-32 in read_buf */ |
|
578
|
|
|
579
|
/* if dictionary would fill window, just replace the history */ |
|
580
|
if (dictLength >= s->w_size) { |
|
581
|
if (wrap == 0) { /* already empty otherwise */ |
|
582
|
CLEAR_HASH(s); |
|
583
|
s->strstart = 0; |
|
584
|
s->block_start = 0L; |
|
585
|
s->insert = 0; |
|
586
|
} |
|
587
|
dictionary += dictLength - s->w_size; /* use the tail */ |
|
588
|
dictLength = s->w_size; |
|
589
|
} |
|
590
|
|
|
591
|
/* insert dictionary into window and hash */ |
|
592
|
avail = strm->avail_in; |
|
593
|
next = strm->next_in; |
|
594
|
strm->avail_in = dictLength; |
|
595
|
strm->next_in = (z_const Bytef *)dictionary; |
|
596
|
fill_window(s); |
|
597
|
while (s->lookahead >= MIN_MATCH) { |
|
598
|
str = s->strstart; |
|
599
|
n = s->lookahead - (MIN_MATCH-1); |
|
600
|
do { |
|
601
|
UPDATE_HASH(s, s->ins_h, s->window[str + MIN_MATCH-1]); |
|
602
|
#ifndef FASTEST |
|
603
|
s->prev[str & s->w_mask] = s->head[s->ins_h]; |
|
604
|
#endif |
|
605
|
s->head[s->ins_h] = (Pos)str; |
|
606
|
str++; |
|
607
|
} while (--n); |
|
608
|
s->strstart = str; |
|
609
|
s->lookahead = MIN_MATCH-1; |
|
610
|
fill_window(s); |
|
611
|
} |
|
612
|
s->strstart += s->lookahead; |
|
613
|
s->block_start = (long)s->strstart; |
|
614
|
s->insert = s->lookahead; |
|
615
|
s->lookahead = 0; |
|
616
|
s->match_length = s->prev_length = MIN_MATCH-1; |
|
617
|
s->match_available = 0; |
|
618
|
strm->next_in = next; |
|
619
|
strm->avail_in = avail; |
|
620
|
s->wrap = wrap; |
|
621
|
return Z_OK; |
|
622
|
} |
|
623
|
|
|
624
|
/* ========================================================================= */ |
|
625
|
int ZEXPORT deflateGetDictionary(z_streamp strm, Bytef *dictionary, |
|
626
|
uInt *dictLength) { |
|
627
|
deflate_state *s; |
|
628
|
uInt len; |
|
629
|
|
|
630
|
if (deflateStateCheck(strm)) |
|
631
|
return Z_STREAM_ERROR; |
|
632
|
s = strm->state; |
|
633
|
len = s->strstart + s->lookahead; |
|
634
|
if (len > s->w_size) |
|
635
|
len = s->w_size; |
|
636
|
if (dictionary != Z_NULL && len) |
|
637
|
zmemcpy(dictionary, s->window + s->strstart + s->lookahead - len, len); |
|
638
|
if (dictLength != Z_NULL) |
|
639
|
*dictLength = len; |
|
640
|
return Z_OK; |
|
641
|
} |
|
642
|
|
|
643
|
/* ========================================================================= */ |
|
644
|
int ZEXPORT deflateResetKeep(z_streamp strm) { |
|
645
|
deflate_state *s; |
|
646
|
|
|
647
|
if (deflateStateCheck(strm)) { |
|
648
|
return Z_STREAM_ERROR; |
|
649
|
} |
|
650
|
|
|
651
|
strm->total_in = strm->total_out = 0; |
|
652
|
strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */ |
|
653
|
strm->data_type = Z_UNKNOWN; |
|
654
|
|
|
655
|
s = (deflate_state *)strm->state; |
|
656
|
s->pending = 0; |
|
657
|
s->pending_out = s->pending_buf; |
|
658
|
|
|
659
|
if (s->wrap < 0) { |
|
660
|
s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */ |
|
661
|
} |
|
662
|
s->status = |
|
663
|
#ifdef GZIP |
|
664
|
s->wrap == 2 ? GZIP_STATE : |
|
665
|
#endif |
|
666
|
INIT_STATE; |
|
667
|
strm->adler = |
|
668
|
#ifdef GZIP |
|
669
|
s->wrap == 2 ? crc32(0L, Z_NULL, 0) : |
|
670
|
#endif |
|
671
|
adler32(0L, Z_NULL, 0); |
|
672
|
s->last_flush = -2; |
|
673
|
|
|
674
|
_tr_init(s); |
|
675
|
|
|
676
|
return Z_OK; |
|
677
|
} |
|
678
|
|
|
679
|
/* =========================================================================== |
|
680
|
* Initialize the "longest match" routines for a new zlib stream |
|
681
|
*/ |
|
682
|
local void lm_init(deflate_state *s) { |
|
683
|
s->window_size = (ulg)2L*s->w_size; |
|
684
|
|
|
685
|
CLEAR_HASH(s); |
|
686
|
|
|
687
|
/* Set the default configuration parameters: |
|
688
|
*/ |
|
689
|
s->max_lazy_match = configuration_table[s->level].max_lazy; |
|
690
|
s->good_match = configuration_table[s->level].good_length; |
|
691
|
s->nice_match = configuration_table[s->level].nice_length; |
|
692
|
s->max_chain_length = configuration_table[s->level].max_chain; |
|
693
|
|
|
694
|
s->strstart = 0; |
|
695
|
s->block_start = 0L; |
|
696
|
s->lookahead = 0; |
|
697
|
s->insert = 0; |
|
698
|
s->match_length = s->prev_length = MIN_MATCH-1; |
|
699
|
s->match_available = 0; |
|
700
|
s->ins_h = 0; |
|
701
|
} |
|
702
|
|
|
703
|
/* ========================================================================= */ |
|
704
|
int ZEXPORT deflateReset(z_streamp strm) { |
|
705
|
int ret; |
|
706
|
|
|
707
|
ret = deflateResetKeep(strm); |
|
708
|
if (ret == Z_OK) |
|
709
|
lm_init(strm->state); |
|
710
|
return ret; |
|
711
|
} |
|
712
|
|
|
713
|
/* ========================================================================= */ |
|
714
|
int ZEXPORT deflateSetHeader(z_streamp strm, gz_headerp head) { |
|
715
|
if (deflateStateCheck(strm) || strm->state->wrap != 2) |
|
716
|
return Z_STREAM_ERROR; |
|
717
|
strm->state->gzhead = head; |
|
718
|
return Z_OK; |
|
719
|
} |
|
720
|
|
|
721
|
/* ========================================================================= */ |
|
722
|
int ZEXPORT deflatePending(z_streamp strm, unsigned *pending, int *bits) { |
|
723
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
|
724
|
if (bits != Z_NULL) |
|
725
|
*bits = strm->state->bi_valid; |
|
726
|
if (pending != Z_NULL) { |
|
727
|
*pending = (unsigned)strm->state->pending; |
|
728
|
if (*pending != strm->state->pending) { |
|
729
|
*pending = (unsigned)-1; |
|
730
|
return Z_BUF_ERROR; |
|
731
|
} |
|
732
|
} |
|
733
|
return Z_OK; |
|
734
|
} |
|
735
|
|
|
736
|
/* ========================================================================= */ |
|
737
|
int ZEXPORT deflateUsed(z_streamp strm, int *bits) { |
|
738
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
|
739
|
if (bits != Z_NULL) |
|
740
|
*bits = strm->state->bi_used; |
|
741
|
return Z_OK; |
|
742
|
} |
|
743
|
|
|
744
|
/* ========================================================================= */ |
|
745
|
int ZEXPORT deflatePrime(z_streamp strm, int bits, int value) { |
|
746
|
deflate_state *s; |
|
747
|
int put; |
|
748
|
|
|
749
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
|
750
|
s = strm->state; |
|
751
|
#ifdef LIT_MEM |
|
752
|
if (bits < 0 || bits > 16 || |
|
753
|
(uchf *)s->d_buf < s->pending_out + ((Buf_size + 7) >> 3)) |
|
754
|
return Z_BUF_ERROR; |
|
755
|
#else |
|
756
|
if (bits < 0 || bits > 16 || |
|
757
|
s->sym_buf < s->pending_out + ((Buf_size + 7) >> 3)) |
|
758
|
return Z_BUF_ERROR; |
|
759
|
#endif |
|
760
|
do { |
|
761
|
put = Buf_size - s->bi_valid; |
|
762
|
if (put > bits) |
|
763
|
put = bits; |
|
764
|
s->bi_buf |= (ush)((value & ((1 << put) - 1)) << s->bi_valid); |
|
765
|
s->bi_valid += put; |
|
766
|
_tr_flush_bits(s); |
|
767
|
value >>= put; |
|
768
|
bits -= put; |
|
769
|
} while (bits); |
|
770
|
return Z_OK; |
|
771
|
} |
|
772
|
|
|
773
|
/* ========================================================================= */ |
|
774
|
int ZEXPORT deflateParams(z_streamp strm, int level, int strategy) { |
|
775
|
deflate_state *s; |
|
776
|
compress_func func; |
|
777
|
|
|
778
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
|
779
|
s = strm->state; |
|
780
|
|
|
781
|
#ifdef FASTEST |
|
782
|
if (level != 0) level = 1; |
|
783
|
#else |
|
784
|
if (level == Z_DEFAULT_COMPRESSION) level = 6; |
|
785
|
#endif |
|
786
|
if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) { |
|
787
|
return Z_STREAM_ERROR; |
|
788
|
} |
|
789
|
func = configuration_table[s->level].func; |
|
790
|
|
|
791
|
if ((strategy != s->strategy || func != configuration_table[level].func) && |
|
792
|
s->last_flush != -2) { |
|
793
|
/* Flush the last buffer: */ |
|
794
|
int err = deflate(strm, Z_BLOCK); |
|
795
|
if (err == Z_STREAM_ERROR) |
|
796
|
return err; |
|
797
|
if (strm->avail_in || (s->strstart - s->block_start) + s->lookahead) |
|
798
|
return Z_BUF_ERROR; |
|
799
|
} |
|
800
|
if (s->level != level) { |
|
801
|
if (s->level == 0 && s->matches != 0) { |
|
802
|
if (s->matches == 1) |
|
803
|
slide_hash(s); |
|
804
|
else |
|
805
|
CLEAR_HASH(s); |
|
806
|
s->matches = 0; |
|
807
|
} |
|
808
|
s->level = level; |
|
809
|
s->max_lazy_match = configuration_table[level].max_lazy; |
|
810
|
s->good_match = configuration_table[level].good_length; |
|
811
|
s->nice_match = configuration_table[level].nice_length; |
|
812
|
s->max_chain_length = configuration_table[level].max_chain; |
|
813
|
} |
|
814
|
s->strategy = strategy; |
|
815
|
return Z_OK; |
|
816
|
} |
|
817
|
|
|
818
|
/* ========================================================================= */ |
|
819
|
int ZEXPORT deflateTune(z_streamp strm, int good_length, int max_lazy, |
|
820
|
int nice_length, int max_chain) { |
|
821
|
deflate_state *s; |
|
822
|
|
|
823
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
|
824
|
s = strm->state; |
|
825
|
s->good_match = (uInt)good_length; |
|
826
|
s->max_lazy_match = (uInt)max_lazy; |
|
827
|
s->nice_match = nice_length; |
|
828
|
s->max_chain_length = (uInt)max_chain; |
|
829
|
return Z_OK; |
|
830
|
} |
|
831
|
|
|
832
|
/* ========================================================================= |
|
833
|
* For the default windowBits of 15 and memLevel of 8, this function returns a |
|
834
|
* close to exact, as well as small, upper bound on the compressed size. This |
|
835
|
* is an expansion of ~0.03%, plus a small constant. |
|
836
|
* |
|
837
|
* For any setting other than those defaults for windowBits and memLevel, one |
|
838
|
* of two worst case bounds is returned. This is at most an expansion of ~4% or |
|
839
|
* ~13%, plus a small constant. |
|
840
|
* |
|
841
|
* Both the 0.03% and 4% derive from the overhead of stored blocks. The first |
|
842
|
* one is for stored blocks of 16383 bytes (memLevel == 8), whereas the second |
|
843
|
* is for stored blocks of 127 bytes (the worst case memLevel == 1). The |
|
844
|
* expansion results from five bytes of header for each stored block. |
|
845
|
* |
|
846
|
* The larger expansion of 13% results from a window size less than or equal to |
|
847
|
* the symbols buffer size (windowBits <= memLevel + 7). In that case some of |
|
848
|
* the data being compressed may have slid out of the sliding window, impeding |
|
849
|
* a stored block from being emitted. Then the only choice is a fixed or |
|
850
|
* dynamic block, where a fixed block limits the maximum expansion to 9 bits |
|
851
|
* per 8-bit byte, plus 10 bits for every block. The smallest block size for |
|
852
|
* which this can occur is 255 (memLevel == 2). |
|
853
|
* |
|
854
|
* Shifts are used to approximate divisions, for speed. |
|
855
|
*/ |
|
856
|
z_size_t ZEXPORT deflateBound_z(z_streamp strm, z_size_t sourceLen) { |
|
857
|
deflate_state *s; |
|
858
|
z_size_t fixedlen, storelen, wraplen, bound; |
|
859
|
|
|
860
|
/* upper bound for fixed blocks with 9-bit literals and length 255 |
|
861
|
(memLevel == 2, which is the lowest that may not use stored blocks) -- |
|
862
|
~13% overhead plus a small constant */ |
|
863
|
fixedlen = sourceLen + (sourceLen >> 3) + (sourceLen >> 8) + |
|
864
|
(sourceLen >> 9) + 4; |
|
865
|
if (fixedlen < sourceLen) |
|
866
|
fixedlen = (z_size_t)-1; |
|
867
|
|
|
868
|
/* upper bound for stored blocks with length 127 (memLevel == 1) -- |
|
869
|
~4% overhead plus a small constant */ |
|
870
|
storelen = sourceLen + (sourceLen >> 5) + (sourceLen >> 7) + |
|
871
|
(sourceLen >> 11) + 7; |
|
872
|
if (storelen < sourceLen) |
|
873
|
storelen = (z_size_t)-1; |
|
874
|
|
|
875
|
/* if can't get parameters, return larger bound plus a wrapper */ |
|
876
|
if (deflateStateCheck(strm)) { |
|
877
|
bound = fixedlen > storelen ? fixedlen : storelen; |
|
878
|
return bound + 18 < bound ? (z_size_t)-1 : bound + 18; |
|
879
|
} |
|
880
|
|
|
881
|
/* compute wrapper length */ |
|
882
|
s = strm->state; |
|
883
|
switch (s->wrap < 0 ? -s->wrap : s->wrap) { |
|
884
|
case 0: /* raw deflate */ |
|
885
|
wraplen = 0; |
|
886
|
break; |
|
887
|
case 1: /* zlib wrapper */ |
|
888
|
wraplen = 6 + (s->strstart ? 4 : 0); |
|
889
|
break; |
|
890
|
#ifdef GZIP |
|
891
|
case 2: /* gzip wrapper */ |
|
892
|
wraplen = 18; |
|
893
|
if (s->gzhead != Z_NULL) { /* user-supplied gzip header */ |
|
894
|
Bytef *str; |
|
895
|
if (s->gzhead->extra != Z_NULL) |
|
896
|
wraplen += 2 + s->gzhead->extra_len; |
|
897
|
str = s->gzhead->name; |
|
898
|
if (str != Z_NULL) |
|
899
|
do { |
|
900
|
wraplen++; |
|
901
|
} while (*str++); |
|
902
|
str = s->gzhead->comment; |
|
903
|
if (str != Z_NULL) |
|
904
|
do { |
|
905
|
wraplen++; |
|
906
|
} while (*str++); |
|
907
|
if (s->gzhead->hcrc) |
|
908
|
wraplen += 2; |
|
909
|
} |
|
910
|
break; |
|
911
|
#endif |
|
912
|
default: /* for compiler happiness */ |
|
913
|
wraplen = 18; |
|
914
|
} |
|
915
|
|
|
916
|
/* if not default parameters, return one of the conservative bounds */ |
|
917
|
if (s->w_bits != 15 || s->hash_bits != 8 + 7) { |
|
918
|
bound = s->w_bits <= s->hash_bits && s->level ? fixedlen : |
|
919
|
storelen; |
|
920
|
return bound + wraplen < bound ? (z_size_t)-1 : bound + wraplen; |
|
921
|
} |
|
922
|
|
|
923
|
/* default settings: return tight bound for that case -- ~0.03% overhead |
|
924
|
plus a small constant */ |
|
925
|
bound = sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + |
|
926
|
(sourceLen >> 25) + 13 - 6 + wraplen; |
|
927
|
return bound < sourceLen ? (z_size_t)-1 : bound; |
|
928
|
} |
|
929
|
uLong ZEXPORT deflateBound(z_streamp strm, uLong sourceLen) { |
|
930
|
z_size_t bound = deflateBound_z(strm, sourceLen); |
|
931
|
return (uLong)bound != bound ? (uLong)-1 : (uLong)bound; |
|
932
|
} |
|
933
|
|
|
934
|
/* ========================================================================= |
|
935
|
* Put a short in the pending buffer. The 16-bit value is put in MSB order. |
|
936
|
* IN assertion: the stream state is correct and there is enough room in |
|
937
|
* pending_buf. |
|
938
|
*/ |
|
939
|
local void putShortMSB(deflate_state *s, uInt b) { |
|
940
|
put_byte(s, (Byte)(b >> 8)); |
|
941
|
put_byte(s, (Byte)(b & 0xff)); |
|
942
|
} |
|
943
|
|
|
944
|
/* ========================================================================= |
|
945
|
* Flush as much pending output as possible. All deflate() output, except for |
|
946
|
* some deflate_stored() output, goes through this function so some |
|
947
|
* applications may wish to modify it to avoid allocating a large |
|
948
|
* strm->next_out buffer and copying into it. (See also read_buf()). |
|
949
|
*/ |
|
950
|
local void flush_pending(z_streamp strm) { |
|
951
|
unsigned len; |
|
952
|
deflate_state *s = strm->state; |
|
953
|
|
|
954
|
_tr_flush_bits(s); |
|
955
|
len = s->pending > strm->avail_out ? strm->avail_out : |
|
956
|
(unsigned)s->pending; |
|
957
|
if (len == 0) return; |
|
958
|
|
|
959
|
zmemcpy(strm->next_out, s->pending_out, len); |
|
960
|
strm->next_out += len; |
|
961
|
s->pending_out += len; |
|
962
|
strm->total_out += len; |
|
963
|
strm->avail_out -= len; |
|
964
|
s->pending -= len; |
|
965
|
if (s->pending == 0) { |
|
966
|
s->pending_out = s->pending_buf; |
|
967
|
} |
|
968
|
} |
|
969
|
|
|
970
|
/* =========================================================================== |
|
971
|
* Update the header CRC with the bytes s->pending_buf[beg..s->pending - 1]. |
|
972
|
*/ |
|
973
|
#define HCRC_UPDATE(beg) \ |
|
974
|
do { \ |
|
975
|
if (s->gzhead->hcrc && s->pending > (beg)) \ |
|
976
|
strm->adler = crc32_z(strm->adler, s->pending_buf + (beg), \ |
|
977
|
s->pending - (beg)); \ |
|
978
|
} while (0) |
|
979
|
|
|
980
|
/* ========================================================================= */ |
|
981
|
int ZEXPORT deflate(z_streamp strm, int flush) { |
|
982
|
int old_flush; /* value of flush param for previous deflate call */ |
|
983
|
deflate_state *s; |
|
984
|
|
|
985
|
if (deflateStateCheck(strm) || flush > Z_BLOCK || flush < 0) { |
|
986
|
return Z_STREAM_ERROR; |
|
987
|
} |
|
988
|
s = strm->state; |
|
989
|
|
|
990
|
if (strm->next_out == Z_NULL || |
|
991
|
(strm->avail_in != 0 && strm->next_in == Z_NULL) || |
|
992
|
(s->status == FINISH_STATE && flush != Z_FINISH)) { |
|
993
|
ERR_RETURN(strm, Z_STREAM_ERROR); |
|
994
|
} |
|
995
|
if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR); |
|
996
|
|
|
997
|
old_flush = s->last_flush; |
|
998
|
s->last_flush = flush; |
|
999
|
|
|
1000
|
/* Flush as much pending output as possible */ |
|
1001
|
if (s->pending != 0) { |
|
1002
|
flush_pending(strm); |
|
1003
|
if (strm->avail_out == 0) { |
|
1004
|
/* Since avail_out is 0, deflate will be called again with |
|
1005
|
* more output space, but possibly with both pending and |
|
1006
|
* avail_in equal to zero. There won't be anything to do, |
|
1007
|
* but this is not an error situation so make sure we |
|
1008
|
* return OK instead of BUF_ERROR at next call of deflate: |
|
1009
|
*/ |
|
1010
|
s->last_flush = -1; |
|
1011
|
return Z_OK; |
|
1012
|
} |
|
1013
|
|
|
1014
|
/* Make sure there is something to do and avoid duplicate consecutive |
|
1015
|
* flushes. For repeated and useless calls with Z_FINISH, we keep |
|
1016
|
* returning Z_STREAM_END instead of Z_BUF_ERROR. |
|
1017
|
*/ |
|
1018
|
} else if (strm->avail_in == 0 && RANK(flush) <= RANK(old_flush) && |
|
1019
|
flush != Z_FINISH) { |
|
1020
|
ERR_RETURN(strm, Z_BUF_ERROR); |
|
1021
|
} |
|
1022
|
|
|
1023
|
/* User must not provide more input after the first FINISH: */ |
|
1024
|
if (s->status == FINISH_STATE && strm->avail_in != 0) { |
|
1025
|
ERR_RETURN(strm, Z_BUF_ERROR); |
|
1026
|
} |
|
1027
|
|
|
1028
|
/* Write the header */ |
|
1029
|
if (s->status == INIT_STATE && s->wrap == 0) |
|
1030
|
s->status = BUSY_STATE; |
|
1031
|
if (s->status == INIT_STATE) { |
|
1032
|
/* zlib header */ |
|
1033
|
uInt header = (Z_DEFLATED + ((s->w_bits - 8) << 4)) << 8; |
|
1034
|
uInt level_flags; |
|
1035
|
|
|
1036
|
if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2) |
|
1037
|
level_flags = 0; |
|
1038
|
else if (s->level < 6) |
|
1039
|
level_flags = 1; |
|
1040
|
else if (s->level == 6) |
|
1041
|
level_flags = 2; |
|
1042
|
else |
|
1043
|
level_flags = 3; |
|
1044
|
header |= (level_flags << 6); |
|
1045
|
if (s->strstart != 0) header |= PRESET_DICT; |
|
1046
|
header += 31 - (header % 31); |
|
1047
|
|
|
1048
|
putShortMSB(s, header); |
|
1049
|
|
|
1050
|
/* Save the adler32 of the preset dictionary: */ |
|
1051
|
if (s->strstart != 0) { |
|
1052
|
putShortMSB(s, (uInt)(strm->adler >> 16)); |
|
1053
|
putShortMSB(s, (uInt)(strm->adler & 0xffff)); |
|
1054
|
} |
|
1055
|
strm->adler = adler32(0L, Z_NULL, 0); |
|
1056
|
s->status = BUSY_STATE; |
|
1057
|
|
|
1058
|
/* Compression must start with an empty pending buffer */ |
|
1059
|
flush_pending(strm); |
|
1060
|
if (s->pending != 0) { |
|
1061
|
s->last_flush = -1; |
|
1062
|
return Z_OK; |
|
1063
|
} |
|
1064
|
} |
|
1065
|
#ifdef GZIP |
|
1066
|
if (s->status == GZIP_STATE) { |
|
1067
|
/* gzip header */ |
|
1068
|
strm->adler = crc32(0L, Z_NULL, 0); |
|
1069
|
put_byte(s, 31); |
|
1070
|
put_byte(s, 139); |
|
1071
|
put_byte(s, 8); |
|
1072
|
if (s->gzhead == Z_NULL) { |
|
1073
|
put_byte(s, 0); |
|
1074
|
put_byte(s, 0); |
|
1075
|
put_byte(s, 0); |
|
1076
|
put_byte(s, 0); |
|
1077
|
put_byte(s, 0); |
|
1078
|
put_byte(s, s->level == 9 ? 2 : |
|
1079
|
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? |
|
1080
|
4 : 0)); |
|
1081
|
put_byte(s, OS_CODE); |
|
1082
|
s->status = BUSY_STATE; |
|
1083
|
|
|
1084
|
/* Compression must start with an empty pending buffer */ |
|
1085
|
flush_pending(strm); |
|
1086
|
if (s->pending != 0) { |
|
1087
|
s->last_flush = -1; |
|
1088
|
return Z_OK; |
|
1089
|
} |
|
1090
|
} |
|
1091
|
else { |
|
1092
|
put_byte(s, (s->gzhead->text ? 1 : 0) + |
|
1093
|
(s->gzhead->hcrc ? 2 : 0) + |
|
1094
|
(s->gzhead->extra == Z_NULL ? 0 : 4) + |
|
1095
|
(s->gzhead->name == Z_NULL ? 0 : 8) + |
|
1096
|
(s->gzhead->comment == Z_NULL ? 0 : 16) |
|
1097
|
); |
|
1098
|
put_byte(s, (Byte)(s->gzhead->time & 0xff)); |
|
1099
|
put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff)); |
|
1100
|
put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff)); |
|
1101
|
put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff)); |
|
1102
|
put_byte(s, s->level == 9 ? 2 : |
|
1103
|
(s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ? |
|
1104
|
4 : 0)); |
|
1105
|
put_byte(s, s->gzhead->os & 0xff); |
|
1106
|
if (s->gzhead->extra != Z_NULL) { |
|
1107
|
put_byte(s, s->gzhead->extra_len & 0xff); |
|
1108
|
put_byte(s, (s->gzhead->extra_len >> 8) & 0xff); |
|
1109
|
} |
|
1110
|
if (s->gzhead->hcrc) |
|
1111
|
strm->adler = crc32_z(strm->adler, s->pending_buf, |
|
1112
|
s->pending); |
|
1113
|
s->gzindex = 0; |
|
1114
|
s->status = EXTRA_STATE; |
|
1115
|
} |
|
1116
|
} |
|
1117
|
if (s->status == EXTRA_STATE) { |
|
1118
|
if (s->gzhead->extra != Z_NULL) { |
|
1119
|
ulg beg = s->pending; /* start of bytes to update crc */ |
|
1120
|
ulg left = (s->gzhead->extra_len & 0xffff) - s->gzindex; |
|
1121
|
while (s->pending + left > s->pending_buf_size) { |
|
1122
|
ulg copy = s->pending_buf_size - s->pending; |
|
1123
|
zmemcpy(s->pending_buf + s->pending, |
|
1124
|
s->gzhead->extra + s->gzindex, copy); |
|
1125
|
s->pending = s->pending_buf_size; |
|
1126
|
HCRC_UPDATE(beg); |
|
1127
|
s->gzindex += copy; |
|
1128
|
flush_pending(strm); |
|
1129
|
if (s->pending != 0) { |
|
1130
|
s->last_flush = -1; |
|
1131
|
return Z_OK; |
|
1132
|
} |
|
1133
|
beg = 0; |
|
1134
|
left -= copy; |
|
1135
|
} |
|
1136
|
zmemcpy(s->pending_buf + s->pending, |
|
1137
|
s->gzhead->extra + s->gzindex, left); |
|
1138
|
s->pending += left; |
|
1139
|
HCRC_UPDATE(beg); |
|
1140
|
s->gzindex = 0; |
|
1141
|
} |
|
1142
|
s->status = NAME_STATE; |
|
1143
|
} |
|
1144
|
if (s->status == NAME_STATE) { |
|
1145
|
if (s->gzhead->name != Z_NULL) { |
|
1146
|
ulg beg = s->pending; /* start of bytes to update crc */ |
|
1147
|
int val; |
|
1148
|
do { |
|
1149
|
if (s->pending == s->pending_buf_size) { |
|
1150
|
HCRC_UPDATE(beg); |
|
1151
|
flush_pending(strm); |
|
1152
|
if (s->pending != 0) { |
|
1153
|
s->last_flush = -1; |
|
1154
|
return Z_OK; |
|
1155
|
} |
|
1156
|
beg = 0; |
|
1157
|
} |
|
1158
|
val = s->gzhead->name[s->gzindex++]; |
|
1159
|
put_byte(s, val); |
|
1160
|
} while (val != 0); |
|
1161
|
HCRC_UPDATE(beg); |
|
1162
|
s->gzindex = 0; |
|
1163
|
} |
|
1164
|
s->status = COMMENT_STATE; |
|
1165
|
} |
|
1166
|
if (s->status == COMMENT_STATE) { |
|
1167
|
if (s->gzhead->comment != Z_NULL) { |
|
1168
|
ulg beg = s->pending; /* start of bytes to update crc */ |
|
1169
|
int val; |
|
1170
|
do { |
|
1171
|
if (s->pending == s->pending_buf_size) { |
|
1172
|
HCRC_UPDATE(beg); |
|
1173
|
flush_pending(strm); |
|
1174
|
if (s->pending != 0) { |
|
1175
|
s->last_flush = -1; |
|
1176
|
return Z_OK; |
|
1177
|
} |
|
1178
|
beg = 0; |
|
1179
|
} |
|
1180
|
val = s->gzhead->comment[s->gzindex++]; |
|
1181
|
put_byte(s, val); |
|
1182
|
} while (val != 0); |
|
1183
|
HCRC_UPDATE(beg); |
|
1184
|
} |
|
1185
|
s->status = HCRC_STATE; |
|
1186
|
} |
|
1187
|
if (s->status == HCRC_STATE) { |
|
1188
|
if (s->gzhead->hcrc) { |
|
1189
|
if (s->pending + 2 > s->pending_buf_size) { |
|
1190
|
flush_pending(strm); |
|
1191
|
if (s->pending != 0) { |
|
1192
|
s->last_flush = -1; |
|
1193
|
return Z_OK; |
|
1194
|
} |
|
1195
|
} |
|
1196
|
put_byte(s, (Byte)(strm->adler & 0xff)); |
|
1197
|
put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); |
|
1198
|
strm->adler = crc32(0L, Z_NULL, 0); |
|
1199
|
} |
|
1200
|
s->status = BUSY_STATE; |
|
1201
|
|
|
1202
|
/* Compression must start with an empty pending buffer */ |
|
1203
|
flush_pending(strm); |
|
1204
|
if (s->pending != 0) { |
|
1205
|
s->last_flush = -1; |
|
1206
|
return Z_OK; |
|
1207
|
} |
|
1208
|
} |
|
1209
|
#endif |
|
1210
|
|
|
1211
|
/* Start a new block or continue the current one. |
|
1212
|
*/ |
|
1213
|
if (strm->avail_in != 0 || s->lookahead != 0 || |
|
1214
|
(flush != Z_NO_FLUSH && s->status != FINISH_STATE)) { |
|
1215
|
block_state bstate; |
|
1216
|
|
|
1217
|
bstate = s->level == 0 ? deflate_stored(s, flush) : |
|
1218
|
s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) : |
|
1219
|
s->strategy == Z_RLE ? deflate_rle(s, flush) : |
|
1220
|
(*(configuration_table[s->level].func))(s, flush); |
|
1221
|
|
|
1222
|
if (bstate == finish_started || bstate == finish_done) { |
|
1223
|
s->status = FINISH_STATE; |
|
1224
|
} |
|
1225
|
if (bstate == need_more || bstate == finish_started) { |
|
1226
|
if (strm->avail_out == 0) { |
|
1227
|
s->last_flush = -1; /* avoid BUF_ERROR next call, see above */ |
|
1228
|
} |
|
1229
|
return Z_OK; |
|
1230
|
/* If flush != Z_NO_FLUSH && avail_out == 0, the next call |
|
1231
|
* of deflate should use the same flush parameter to make sure |
|
1232
|
* that the flush is complete. So we don't have to output an |
|
1233
|
* empty block here, this will be done at next call. This also |
|
1234
|
* ensures that for a very small output buffer, we emit at most |
|
1235
|
* one empty block. |
|
1236
|
*/ |
|
1237
|
} |
|
1238
|
if (bstate == block_done) { |
|
1239
|
if (flush == Z_PARTIAL_FLUSH) { |
|
1240
|
_tr_align(s); |
|
1241
|
} else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */ |
|
1242
|
_tr_stored_block(s, (char*)0, 0L, 0); |
|
1243
|
/* For a full flush, this empty block will be recognized |
|
1244
|
* as a special marker by inflate_sync(). |
|
1245
|
*/ |
|
1246
|
if (flush == Z_FULL_FLUSH) { |
|
1247
|
CLEAR_HASH(s); /* forget history */ |
|
1248
|
if (s->lookahead == 0) { |
|
1249
|
s->strstart = 0; |
|
1250
|
s->block_start = 0L; |
|
1251
|
s->insert = 0; |
|
1252
|
} |
|
1253
|
} |
|
1254
|
} |
|
1255
|
flush_pending(strm); |
|
1256
|
if (strm->avail_out == 0) { |
|
1257
|
s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */ |
|
1258
|
return Z_OK; |
|
1259
|
} |
|
1260
|
} |
|
1261
|
} |
|
1262
|
|
|
1263
|
if (flush != Z_FINISH) return Z_OK; |
|
1264
|
if (s->wrap <= 0) return Z_STREAM_END; |
|
1265
|
|
|
1266
|
/* Write the trailer */ |
|
1267
|
#ifdef GZIP |
|
1268
|
if (s->wrap == 2) { |
|
1269
|
put_byte(s, (Byte)(strm->adler & 0xff)); |
|
1270
|
put_byte(s, (Byte)((strm->adler >> 8) & 0xff)); |
|
1271
|
put_byte(s, (Byte)((strm->adler >> 16) & 0xff)); |
|
1272
|
put_byte(s, (Byte)((strm->adler >> 24) & 0xff)); |
|
1273
|
put_byte(s, (Byte)(strm->total_in & 0xff)); |
|
1274
|
put_byte(s, (Byte)((strm->total_in >> 8) & 0xff)); |
|
1275
|
put_byte(s, (Byte)((strm->total_in >> 16) & 0xff)); |
|
1276
|
put_byte(s, (Byte)((strm->total_in >> 24) & 0xff)); |
|
1277
|
} |
|
1278
|
else |
|
1279
|
#endif |
|
1280
|
{ |
|
1281
|
putShortMSB(s, (uInt)(strm->adler >> 16)); |
|
1282
|
putShortMSB(s, (uInt)(strm->adler & 0xffff)); |
|
1283
|
} |
|
1284
|
flush_pending(strm); |
|
1285
|
/* If avail_out is zero, the application will call deflate again |
|
1286
|
* to flush the rest. |
|
1287
|
*/ |
|
1288
|
if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */ |
|
1289
|
return s->pending != 0 ? Z_OK : Z_STREAM_END; |
|
1290
|
} |
|
1291
|
|
|
1292
|
/* ========================================================================= */ |
|
1293
|
int ZEXPORT deflateEnd(z_streamp strm) { |
|
1294
|
int status; |
|
1295
|
|
|
1296
|
if (deflateStateCheck(strm)) return Z_STREAM_ERROR; |
|
1297
|
|
|
1298
|
status = strm->state->status; |
|
1299
|
|
|
1300
|
/* Deallocate in reverse order of allocations: */ |
|
1301
|
TRY_FREE(strm, strm->state->pending_buf); |
|
1302
|
TRY_FREE(strm, strm->state->head); |
|
1303
|
TRY_FREE(strm, strm->state->prev); |
|
1304
|
TRY_FREE(strm, strm->state->window); |
|
1305
|
|
|
1306
|
ZFREE(strm, strm->state); |
|
1307
|
strm->state = Z_NULL; |
|
1308
|
|
|
1309
|
return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK; |
|
1310
|
} |
|
1311
|
|
|
1312
|
/* ========================================================================= |
|
1313
|
* Copy the source state to the destination state. |
|
1314
|
* To simplify the source, this is not supported for 16-bit MSDOS (which |
|
1315
|
* doesn't have enough memory anyway to duplicate compression states). |
|
1316
|
*/ |
|
1317
|
int ZEXPORT deflateCopy(z_streamp dest, z_streamp source) { |
|
1318
|
#ifdef MAXSEG_64K |
|
1319
|
(void)dest; |
|
1320
|
(void)source; |
|
1321
|
return Z_STREAM_ERROR; |
|
1322
|
#else |
|
1323
|
deflate_state *ds; |
|
1324
|
deflate_state *ss; |
|
1325
|
|
|
1326
|
|
|
1327
|
if (deflateStateCheck(source) || dest == Z_NULL) { |
|
1328
|
return Z_STREAM_ERROR; |
|
1329
|
} |
|
1330
|
|
|
1331
|
ss = source->state; |
|
1332
|
|
|
1333
|
zmemcpy(dest, source, sizeof(z_stream)); |
|
1334
|
|
|
1335
|
ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state)); |
|
1336
|
if (ds == Z_NULL) return Z_MEM_ERROR; |
|
1337
|
zmemzero(ds, sizeof(deflate_state)); |
|
1338
|
dest->state = (struct internal_state FAR *) ds; |
|
1339
|
zmemcpy(ds, ss, sizeof(deflate_state)); |
|
1340
|
ds->strm = dest; |
|
1341
|
|
|
1342
|
ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte)); |
|
1343
|
ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos)); |
|
1344
|
ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos)); |
|
1345
|
ds->pending_buf = (uchf *) ZALLOC(dest, ds->lit_bufsize, LIT_BUFS); |
|
1346
|
|
|
1347
|
if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL || |
|
1348
|
ds->pending_buf == Z_NULL) { |
|
1349
|
deflateEnd (dest); |
|
1350
|
return Z_MEM_ERROR; |
|
1351
|
} |
|
1352
|
/* following zmemcpy's do not work for 16-bit MSDOS */ |
|
1353
|
zmemcpy(ds->window, ss->window, ss->high_water); |
|
1354
|
zmemcpy(ds->prev, ss->prev, |
|
1355
|
(ss->slid || ss->strstart - ss->insert > ds->w_size ? ds->w_size : |
|
1356
|
ss->strstart - ss->insert) * sizeof(Pos)); |
|
1357
|
zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos)); |
|
1358
|
|
|
1359
|
ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf); |
|
1360
|
zmemcpy(ds->pending_out, ss->pending_out, ss->pending); |
|
1361
|
#ifdef LIT_MEM |
|
1362
|
ds->d_buf = (ushf *)(ds->pending_buf + (ds->lit_bufsize << 1)); |
|
1363
|
ds->l_buf = ds->pending_buf + (ds->lit_bufsize << 2); |
|
1364
|
zmemcpy(ds->d_buf, ss->d_buf, ss->sym_next * sizeof(ush)); |
|
1365
|
zmemcpy(ds->l_buf, ss->l_buf, ss->sym_next); |
|
1366
|
#else |
|
1367
|
ds->sym_buf = ds->pending_buf + ds->lit_bufsize; |
|
1368
|
zmemcpy(ds->sym_buf, ss->sym_buf, ss->sym_next); |
|
1369
|
#endif |
|
1370
|
|
|
1371
|
ds->l_desc.dyn_tree = ds->dyn_ltree; |
|
1372
|
ds->d_desc.dyn_tree = ds->dyn_dtree; |
|
1373
|
ds->bl_desc.dyn_tree = ds->bl_tree; |
|
1374
|
|
|
1375
|
return Z_OK; |
|
1376
|
#endif /* MAXSEG_64K */ |
|
1377
|
} |
|
1378
|
|
|
1379
|
#ifndef FASTEST |
|
1380
|
/* =========================================================================== |
|
1381
|
* Set match_start to the longest match starting at the given string and |
|
1382
|
* return its length. Matches shorter or equal to prev_length are discarded, |
|
1383
|
* in which case the result is equal to prev_length and match_start is |
|
1384
|
* garbage. |
|
1385
|
* IN assertions: cur_match is the head of the hash chain for the current |
|
1386
|
* string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1 |
|
1387
|
* OUT assertion: the match length is not greater than s->lookahead. |
|
1388
|
*/ |
|
1389
|
local uInt longest_match(deflate_state *s, IPos cur_match) { |
|
1390
|
unsigned chain_length = s->max_chain_length;/* max hash chain length */ |
|
1391
|
Bytef *scan = s->window + s->strstart; /* current string */ |
|
1392
|
Bytef *match; /* matched string */ |
|
1393
|
int len; /* length of current match */ |
|
1394
|
int best_len = (int)s->prev_length; /* best match length so far */ |
|
1395
|
int nice_match = s->nice_match; /* stop if match long enough */ |
|
1396
|
IPos limit = s->strstart > (IPos)MAX_DIST(s) ? |
|
1397
|
s->strstart - (IPos)MAX_DIST(s) : NIL; |
|
1398
|
/* Stop when cur_match becomes <= limit. To simplify the code, |
|
1399
|
* we prevent matches with the string of window index 0. |
|
1400
|
*/ |
|
1401
|
Posf *prev = s->prev; |
|
1402
|
uInt wmask = s->w_mask; |
|
1403
|
|
|
1404
|
#ifdef UNALIGNED_OK |
|
1405
|
/* Compare two bytes at a time. Note: this is not always beneficial. |
|
1406
|
* Try with and without -DUNALIGNED_OK to check. |
|
1407
|
*/ |
|
1408
|
Bytef *strend = s->window + s->strstart + MAX_MATCH - 1; |
|
1409
|
ush scan_start = *(ushf*)scan; |
|
1410
|
ush scan_end = *(ushf*)(scan + best_len - 1); |
|
1411
|
#else |
|
1412
|
Bytef *strend = s->window + s->strstart + MAX_MATCH; |
|
1413
|
Byte scan_end1 = scan[best_len - 1]; |
|
1414
|
Byte scan_end = scan[best_len]; |
|
1415
|
#endif |
|
1416
|
|
|
1417
|
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. |
|
1418
|
* It is easy to get rid of this optimization if necessary. |
|
1419
|
*/ |
|
1420
|
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); |
|
1421
|
|
|
1422
|
/* Do not waste too much time if we already have a good match: */ |
|
1423
|
if (s->prev_length >= s->good_match) { |
|
1424
|
chain_length >>= 2; |
|
1425
|
} |
|
1426
|
/* Do not look for matches beyond the end of the input. This is necessary |
|
1427
|
* to make deflate deterministic. |
|
1428
|
*/ |
|
1429
|
if ((uInt)nice_match > s->lookahead) nice_match = (int)s->lookahead; |
|
1430
|
|
|
1431
|
Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, |
|
1432
|
"need lookahead"); |
|
1433
|
|
|
1434
|
do { |
|
1435
|
Assert(cur_match < s->strstart, "no future"); |
|
1436
|
match = s->window + cur_match; |
|
1437
|
|
|
1438
|
/* Skip to next match if the match length cannot increase |
|
1439
|
* or if the match length is less than 2. Note that the checks below |
|
1440
|
* for insufficient lookahead only occur occasionally for performance |
|
1441
|
* reasons. Therefore uninitialized memory will be accessed, and |
|
1442
|
* conditional jumps will be made that depend on those values. |
|
1443
|
* However the length of the match is limited to the lookahead, so |
|
1444
|
* the output of deflate is not affected by the uninitialized values. |
|
1445
|
*/ |
|
1446
|
#if (defined(UNALIGNED_OK) && MAX_MATCH == 258) |
|
1447
|
/* This code assumes sizeof(unsigned short) == 2. Do not use |
|
1448
|
* UNALIGNED_OK if your compiler uses a different size. |
|
1449
|
*/ |
|
1450
|
if (*(ushf*)(match + best_len - 1) != scan_end || |
|
1451
|
*(ushf*)match != scan_start) continue; |
|
1452
|
|
|
1453
|
/* It is not necessary to compare scan[2] and match[2] since they are |
|
1454
|
* always equal when the other bytes match, given that the hash keys |
|
1455
|
* are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at |
|
1456
|
* strstart + 3, + 5, up to strstart + 257. We check for insufficient |
|
1457
|
* lookahead only every 4th comparison; the 128th check will be made |
|
1458
|
* at strstart + 257. If MAX_MATCH-2 is not a multiple of 8, it is |
|
1459
|
* necessary to put more guard bytes at the end of the window, or |
|
1460
|
* to check more often for insufficient lookahead. |
|
1461
|
*/ |
|
1462
|
Assert(scan[2] == match[2], "scan[2]?"); |
|
1463
|
scan++, match++; |
|
1464
|
do { |
|
1465
|
} while (*(ushf*)(scan += 2) == *(ushf*)(match += 2) && |
|
1466
|
*(ushf*)(scan += 2) == *(ushf*)(match += 2) && |
|
1467
|
*(ushf*)(scan += 2) == *(ushf*)(match += 2) && |
|
1468
|
*(ushf*)(scan += 2) == *(ushf*)(match += 2) && |
|
1469
|
scan < strend); |
|
1470
|
/* The funny "do {}" generates better code on most compilers */ |
|
1471
|
|
|
1472
|
/* Here, scan <= window + strstart + 257 */ |
|
1473
|
Assert(scan <= s->window + (unsigned)(s->window_size - 1), |
|
1474
|
"wild scan"); |
|
1475
|
if (*scan == *match) scan++; |
|
1476
|
|
|
1477
|
len = (MAX_MATCH - 1) - (int)(strend - scan); |
|
1478
|
scan = strend - (MAX_MATCH-1); |
|
1479
|
|
|
1480
|
#else /* UNALIGNED_OK */ |
|
1481
|
|
|
1482
|
if (match[best_len] != scan_end || |
|
1483
|
match[best_len - 1] != scan_end1 || |
|
1484
|
*match != *scan || |
|
1485
|
*++match != scan[1]) continue; |
|
1486
|
|
|
1487
|
/* The check at best_len - 1 can be removed because it will be made |
|
1488
|
* again later. (This heuristic is not always a win.) |
|
1489
|
* It is not necessary to compare scan[2] and match[2] since they |
|
1490
|
* are always equal when the other bytes match, given that |
|
1491
|
* the hash keys are equal and that HASH_BITS >= 8. |
|
1492
|
*/ |
|
1493
|
scan += 2, match++; |
|
1494
|
Assert(*scan == *match, "match[2]?"); |
|
1495
|
|
|
1496
|
/* We check for insufficient lookahead only every 8th comparison; |
|
1497
|
* the 256th check will be made at strstart + 258. |
|
1498
|
*/ |
|
1499
|
do { |
|
1500
|
} while (*++scan == *++match && *++scan == *++match && |
|
1501
|
*++scan == *++match && *++scan == *++match && |
|
1502
|
*++scan == *++match && *++scan == *++match && |
|
1503
|
*++scan == *++match && *++scan == *++match && |
|
1504
|
scan < strend); |
|
1505
|
|
|
1506
|
Assert(scan <= s->window + (unsigned)(s->window_size - 1), |
|
1507
|
"wild scan"); |
|
1508
|
|
|
1509
|
len = MAX_MATCH - (int)(strend - scan); |
|
1510
|
scan = strend - MAX_MATCH; |
|
1511
|
|
|
1512
|
#endif /* UNALIGNED_OK */ |
|
1513
|
|
|
1514
|
if (len > best_len) { |
|
1515
|
s->match_start = cur_match; |
|
1516
|
best_len = len; |
|
1517
|
if (len >= nice_match) break; |
|
1518
|
#ifdef UNALIGNED_OK |
|
1519
|
scan_end = *(ushf*)(scan + best_len - 1); |
|
1520
|
#else |
|
1521
|
scan_end1 = scan[best_len - 1]; |
|
1522
|
scan_end = scan[best_len]; |
|
1523
|
#endif |
|
1524
|
} |
|
1525
|
} while ((cur_match = prev[cur_match & wmask]) > limit |
|
1526
|
&& --chain_length != 0); |
|
1527
|
|
|
1528
|
if ((uInt)best_len <= s->lookahead) return (uInt)best_len; |
|
1529
|
return s->lookahead; |
|
1530
|
} |
|
1531
|
|
|
1532
|
#else /* FASTEST */ |
|
1533
|
|
|
1534
|
/* --------------------------------------------------------------------------- |
|
1535
|
* Optimized version for FASTEST only |
|
1536
|
*/ |
|
1537
|
local uInt longest_match(deflate_state *s, IPos cur_match) { |
|
1538
|
Bytef *scan = s->window + s->strstart; /* current string */ |
|
1539
|
Bytef *match; /* matched string */ |
|
1540
|
int len; /* length of current match */ |
|
1541
|
Bytef *strend = s->window + s->strstart + MAX_MATCH; |
|
1542
|
|
|
1543
|
/* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16. |
|
1544
|
* It is easy to get rid of this optimization if necessary. |
|
1545
|
*/ |
|
1546
|
Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever"); |
|
1547
|
|
|
1548
|
Assert((ulg)s->strstart <= s->window_size - MIN_LOOKAHEAD, |
|
1549
|
"need lookahead"); |
|
1550
|
|
|
1551
|
Assert(cur_match < s->strstart, "no future"); |
|
1552
|
|
|
1553
|
match = s->window + cur_match; |
|
1554
|
|
|
1555
|
/* Return failure if the match length is less than 2: |
|
1556
|
*/ |
|
1557
|
if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1; |
|
1558
|
|
|
1559
|
/* The check at best_len - 1 can be removed because it will be made |
|
1560
|
* again later. (This heuristic is not always a win.) |
|
1561
|
* It is not necessary to compare scan[2] and match[2] since they |
|
1562
|
* are always equal when the other bytes match, given that |
|
1563
|
* the hash keys are equal and that HASH_BITS >= 8. |
|
1564
|
*/ |
|
1565
|
scan += 2, match += 2; |
|
1566
|
Assert(*scan == *match, "match[2]?"); |
|
1567
|
|
|
1568
|
/* We check for insufficient lookahead only every 8th comparison; |
|
1569
|
* the 256th check will be made at strstart + 258. |
|
1570
|
*/ |
|
1571
|
do { |
|
1572
|
} while (*++scan == *++match && *++scan == *++match && |
|
1573
|
*++scan == *++match && *++scan == *++match && |
|
1574
|
*++scan == *++match && *++scan == *++match && |
|
1575
|
*++scan == *++match && *++scan == *++match && |
|
1576
|
scan < strend); |
|
1577
|
|
|
1578
|
Assert(scan <= s->window + (unsigned)(s->window_size - 1), "wild scan"); |
|
1579
|
|
|
1580
|
len = MAX_MATCH - (int)(strend - scan); |
|
1581
|
|
|
1582
|
if (len < MIN_MATCH) return MIN_MATCH - 1; |
|
1583
|
|
|
1584
|
s->match_start = cur_match; |
|
1585
|
return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead; |
|
1586
|
} |
|
1587
|
|
|
1588
|
#endif /* FASTEST */ |
|
1589
|
|
|
1590
|
#ifdef ZLIB_DEBUG |
|
1591
|
|
|
1592
|
#define EQUAL 0 |
|
1593
|
/* result of memcmp for equal strings */ |
|
1594
|
|
|
1595
|
/* =========================================================================== |
|
1596
|
* Check that the match at match_start is indeed a match. |
|
1597
|
*/ |
|
1598
|
local void check_match(deflate_state *s, IPos start, IPos match, int length) { |
|
1599
|
/* check that the match is indeed a match */ |
|
1600
|
Bytef *back = s->window + (int)match, *here = s->window + start; |
|
1601
|
IPos len = (IPos)length; |
|
1602
|
if (match == (IPos)-1) { |
|
1603
|
/* match starts one byte before the current window -- just compare the |
|
1604
|
subsequent length-1 bytes */ |
|
1605
|
back++; |
|
1606
|
here++; |
|
1607
|
len--; |
|
1608
|
} |
|
1609
|
if (zmemcmp(back, here, len) != EQUAL) { |
|
1610
|
fprintf(stderr, " start %u, match %d, length %d\n", |
|
1611
|
start, (int)match, length); |
|
1612
|
do { |
|
1613
|
fprintf(stderr, "(%02x %02x)", *back++, *here++); |
|
1614
|
} while (--len != 0); |
|
1615
|
z_error("invalid match"); |
|
1616
|
} |
|
1617
|
if (z_verbose > 1) { |
|
1618
|
fprintf(stderr,"\\[%d,%d]", start - match, length); |
|
1619
|
do { putc(s->window[start++], stderr); } while (--length != 0); |
|
1620
|
} |
|
1621
|
} |
|
1622
|
#else |
|
1623
|
# define check_match(s, start, match, length) |
|
1624
|
#endif /* ZLIB_DEBUG */ |
|
1625
|
|
|
1626
|
/* =========================================================================== |
|
1627
|
* Flush the current block, with given end-of-file flag. |
|
1628
|
* IN assertion: strstart is set to the end of the current match. |
|
1629
|
*/ |
|
1630
|
#define FLUSH_BLOCK_ONLY(s, last) { \ |
|
1631
|
_tr_flush_block(s, (s->block_start >= 0L ? \ |
|
1632
|
(charf *)&s->window[(unsigned)s->block_start] : \ |
|
1633
|
(charf *)Z_NULL), \ |
|
1634
|
(ulg)((long)s->strstart - s->block_start), \ |
|
1635
|
(last)); \ |
|
1636
|
s->block_start = s->strstart; \ |
|
1637
|
flush_pending(s->strm); \ |
|
1638
|
Tracev((stderr,"[FLUSH]")); \ |
|
1639
|
} |
|
1640
|
|
|
1641
|
/* Same but force premature exit if necessary. */ |
|
1642
|
#define FLUSH_BLOCK(s, last) { \ |
|
1643
|
FLUSH_BLOCK_ONLY(s, last); \ |
|
1644
|
if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \ |
|
1645
|
} |
|
1646
|
|
|
1647
|
/* Maximum stored block length in deflate format (not including header). */ |
|
1648
|
#define MAX_STORED 65535 |
|
1649
|
|
|
1650
|
/* Minimum of a and b. */ |
|
1651
|
#define MIN(a, b) ((a) > (b) ? (b) : (a)) |
|
1652
|
|
|
1653
|
/* =========================================================================== |
|
1654
|
* Copy without compression as much as possible from the input stream, return |
|
1655
|
* the current block state. |
|
1656
|
* |
|
1657
|
* In case deflateParams() is used to later switch to a non-zero compression |
|
1658
|
* level, s->matches (otherwise unused when storing) keeps track of the number |
|
1659
|
* of hash table slides to perform. If s->matches is 1, then one hash table |
|
1660
|
* slide will be done when switching. If s->matches is 2, the maximum value |
|
1661
|
* allowed here, then the hash table will be cleared, since two or more slides |
|
1662
|
* is the same as a clear. |
|
1663
|
* |
|
1664
|
* deflate_stored() is written to minimize the number of times an input byte is |
|
1665
|
* copied. It is most efficient with large input and output buffers, which |
|
1666
|
* maximizes the opportunities to have a single copy from next_in to next_out. |
|
1667
|
*/ |
|
1668
|
local block_state deflate_stored(deflate_state *s, int flush) { |
|
1669
|
/* Smallest worthy block size when not flushing or finishing. By default |
|
1670
|
* this is 32K. This can be as small as 507 bytes for memLevel == 1. For |
|
1671
|
* large input and output buffers, the stored block size will be larger. |
|
1672
|
*/ |
|
1673
|
unsigned min_block = (unsigned)(MIN(s->pending_buf_size - 5, s->w_size)); |
|
1674
|
|
|
1675
|
/* Copy as many min_block or larger stored blocks directly to next_out as |
|
1676
|
* possible. If flushing, copy the remaining available input to next_out as |
|
1677
|
* stored blocks, if there is enough space. |
|
1678
|
*/ |
|
1679
|
int last = 0; |
|
1680
|
unsigned len, left, have; |
|
1681
|
unsigned used = s->strm->avail_in; |
|
1682
|
do { |
|
1683
|
/* Set len to the maximum size block that we can copy directly with the |
|
1684
|
* available input data and output space. Set left to how much of that |
|
1685
|
* would be copied from what's left in the window. |
|
1686
|
*/ |
|
1687
|
len = MAX_STORED; /* maximum deflate stored block length */ |
|
1688
|
have = ((unsigned)s->bi_valid + 42) >> 3; /* bytes in header */ |
|
1689
|
if (s->strm->avail_out < have) /* need room for header */ |
|
1690
|
break; |
|
1691
|
/* maximum stored block length that will fit in avail_out: */ |
|
1692
|
have = s->strm->avail_out - have; |
|
1693
|
left = (unsigned)(s->strstart - s->block_start); /* window bytes */ |
|
1694
|
if (len > (ulg)left + s->strm->avail_in) |
|
1695
|
len = left + s->strm->avail_in; /* limit len to the input */ |
|
1696
|
if (len > have) |
|
1697
|
len = have; /* limit len to the output */ |
|
1698
|
|
|
1699
|
/* If the stored block would be less than min_block in length, or if |
|
1700
|
* unable to copy all of the available input when flushing, then try |
|
1701
|
* copying to the window and the pending buffer instead. Also don't |
|
1702
|
* write an empty block when flushing -- deflate() does that. |
|
1703
|
*/ |
|
1704
|
if (len < min_block && ((len == 0 && flush != Z_FINISH) || |
|
1705
|
flush == Z_NO_FLUSH || |
|
1706
|
len != left + s->strm->avail_in)) |
|
1707
|
break; |
|
1708
|
|
|
1709
|
/* Make a dummy stored block in pending to get the header bytes, |
|
1710
|
* including any pending bits. This also updates the debugging counts. |
|
1711
|
*/ |
|
1712
|
last = flush == Z_FINISH && len == left + s->strm->avail_in ? 1 : 0; |
|
1713
|
_tr_stored_block(s, (char *)0, 0L, last); |
|
1714
|
|
|
1715
|
/* Replace the lengths in the dummy stored block with len. */ |
|
1716
|
s->pending_buf[s->pending - 4] = (Bytef)len; |
|
1717
|
s->pending_buf[s->pending - 3] = (Bytef)(len >> 8); |
|
1718
|
s->pending_buf[s->pending - 2] = (Bytef)~len; |
|
1719
|
s->pending_buf[s->pending - 1] = (Bytef)(~len >> 8); |
|
1720
|
|
|
1721
|
/* Write the stored block header bytes. */ |
|
1722
|
flush_pending(s->strm); |
|
1723
|
|
|
1724
|
#ifdef ZLIB_DEBUG |
|
1725
|
/* Update debugging counts for the data about to be copied. */ |
|
1726
|
s->compressed_len += len << 3; |
|
1727
|
s->bits_sent += len << 3; |
|
1728
|
#endif |
|
1729
|
|
|
1730
|
/* Copy uncompressed bytes from the window to next_out. */ |
|
1731
|
if (left) { |
|
1732
|
if (left > len) |
|
1733
|
left = len; |
|
1734
|
zmemcpy(s->strm->next_out, s->window + s->block_start, left); |
|
1735
|
s->strm->next_out += left; |
|
1736
|
s->strm->avail_out -= left; |
|
1737
|
s->strm->total_out += left; |
|
1738
|
s->block_start += left; |
|
1739
|
len -= left; |
|
1740
|
} |
|
1741
|
|
|
1742
|
/* Copy uncompressed bytes directly from next_in to next_out, updating |
|
1743
|
* the check value. |
|
1744
|
*/ |
|
1745
|
if (len) { |
|
1746
|
read_buf(s->strm, s->strm->next_out, len); |
|
1747
|
s->strm->next_out += len; |
|
1748
|
s->strm->avail_out -= len; |
|
1749
|
s->strm->total_out += len; |
|
1750
|
} |
|
1751
|
} while (last == 0); |
|
1752
|
|
|
1753
|
/* Update the sliding window with the last s->w_size bytes of the copied |
|
1754
|
* data, or append all of the copied data to the existing window if less |
|
1755
|
* than s->w_size bytes were copied. Also update the number of bytes to |
|
1756
|
* insert in the hash tables, in the event that deflateParams() switches to |
|
1757
|
* a non-zero compression level. |
|
1758
|
*/ |
|
1759
|
used -= s->strm->avail_in; /* number of input bytes directly copied */ |
|
1760
|
if (used) { |
|
1761
|
/* If any input was used, then no unused input remains in the window, |
|
1762
|
* therefore s->block_start == s->strstart. |
|
1763
|
*/ |
|
1764
|
if (used >= s->w_size) { /* supplant the previous history */ |
|
1765
|
s->matches = 2; /* clear hash */ |
|
1766
|
zmemcpy(s->window, s->strm->next_in - s->w_size, s->w_size); |
|
1767
|
s->strstart = s->w_size; |
|
1768
|
s->insert = s->strstart; |
|
1769
|
} |
|
1770
|
else { |
|
1771
|
if (s->window_size - s->strstart <= used) { |
|
1772
|
/* Slide the window down. */ |
|
1773
|
s->strstart -= s->w_size; |
|
1774
|
zmemcpy(s->window, s->window + s->w_size, s->strstart); |
|
1775
|
if (s->matches < 2) |
|
1776
|
s->matches++; /* add a pending slide_hash() */ |
|
1777
|
if (s->insert > s->strstart) |
|
1778
|
s->insert = s->strstart; |
|
1779
|
} |
|
1780
|
zmemcpy(s->window + s->strstart, s->strm->next_in - used, used); |
|
1781
|
s->strstart += used; |
|
1782
|
s->insert += MIN(used, s->w_size - s->insert); |
|
1783
|
} |
|
1784
|
s->block_start = s->strstart; |
|
1785
|
} |
|
1786
|
if (s->high_water < s->strstart) |
|
1787
|
s->high_water = s->strstart; |
|
1788
|
|
|
1789
|
/* If the last block was written to next_out, then done. */ |
|
1790
|
if (last) { |
|
1791
|
s->bi_used = 8; |
|
1792
|
return finish_done; |
|
1793
|
} |
|
1794
|
|
|
1795
|
/* If flushing and all input has been consumed, then done. */ |
|
1796
|
if (flush != Z_NO_FLUSH && flush != Z_FINISH && |
|
1797
|
s->strm->avail_in == 0 && (long)s->strstart == s->block_start) |
|
1798
|
return block_done; |
|
1799
|
|
|
1800
|
/* Fill the window with any remaining input. */ |
|
1801
|
have = (unsigned)(s->window_size - s->strstart); |
|
1802
|
if (s->strm->avail_in > have && s->block_start >= (long)s->w_size) { |
|
1803
|
/* Slide the window down. */ |
|
1804
|
s->block_start -= s->w_size; |
|
1805
|
s->strstart -= s->w_size; |
|
1806
|
zmemcpy(s->window, s->window + s->w_size, s->strstart); |
|
1807
|
if (s->matches < 2) |
|
1808
|
s->matches++; /* add a pending slide_hash() */ |
|
1809
|
have += s->w_size; /* more space now */ |
|
1810
|
if (s->insert > s->strstart) |
|
1811
|
s->insert = s->strstart; |
|
1812
|
} |
|
1813
|
if (have > s->strm->avail_in) |
|
1814
|
have = s->strm->avail_in; |
|
1815
|
if (have) { |
|
1816
|
read_buf(s->strm, s->window + s->strstart, have); |
|
1817
|
s->strstart += have; |
|
1818
|
s->insert += MIN(have, s->w_size - s->insert); |
|
1819
|
} |
|
1820
|
if (s->high_water < s->strstart) |
|
1821
|
s->high_water = s->strstart; |
|
1822
|
|
|
1823
|
/* There was not enough avail_out to write a complete worthy or flushed |
|
1824
|
* stored block to next_out. Write a stored block to pending instead, if we |
|
1825
|
* have enough input for a worthy block, or if flushing and there is enough |
|
1826
|
* room for the remaining input as a stored block in the pending buffer. |
|
1827
|
*/ |
|
1828
|
have = ((unsigned)s->bi_valid + 42) >> 3; /* bytes in header */ |
|
1829
|
/* maximum stored block length that will fit in pending: */ |
|
1830
|
have = (unsigned)MIN(s->pending_buf_size - have, MAX_STORED); |
|
1831
|
min_block = MIN(have, s->w_size); |
|
1832
|
left = (unsigned)(s->strstart - s->block_start); |
|
1833
|
if (left >= min_block || |
|
1834
|
((left || flush == Z_FINISH) && flush != Z_NO_FLUSH && |
|
1835
|
s->strm->avail_in == 0 && left <= have)) { |
|
1836
|
len = MIN(left, have); |
|
1837
|
last = flush == Z_FINISH && s->strm->avail_in == 0 && |
|
1838
|
len == left ? 1 : 0; |
|
1839
|
_tr_stored_block(s, (charf *)s->window + s->block_start, len, last); |
|
1840
|
s->block_start += len; |
|
1841
|
flush_pending(s->strm); |
|
1842
|
} |
|
1843
|
|
|
1844
|
/* We've done all we can with the available input and output. */ |
|
1845
|
if (last) |
|
1846
|
s->bi_used = 8; |
|
1847
|
return last ? finish_started : need_more; |
|
1848
|
} |
|
1849
|
|
|
1850
|
/* =========================================================================== |
|
1851
|
* Compress as much as possible from the input stream, return the current |
|
1852
|
* block state. |
|
1853
|
* This function does not perform lazy evaluation of matches and inserts |
|
1854
|
* new strings in the dictionary only for unmatched strings or for short |
|
1855
|
* matches. It is used only for the fast compression options. |
|
1856
|
*/ |
|
1857
|
local block_state deflate_fast(deflate_state *s, int flush) { |
|
1858
|
IPos hash_head; /* head of the hash chain */ |
|
1859
|
int bflush; /* set if current block must be flushed */ |
|
1860
|
|
|
1861
|
for (;;) { |
|
1862
|
/* Make sure that we always have enough lookahead, except |
|
1863
|
* at the end of the input file. We need MAX_MATCH bytes |
|
1864
|
* for the next match, plus MIN_MATCH bytes to insert the |
|
1865
|
* string following the next match. |
|
1866
|
*/ |
|
1867
|
if (s->lookahead < MIN_LOOKAHEAD) { |
|
1868
|
fill_window(s); |
|
1869
|
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { |
|
1870
|
return need_more; |
|
1871
|
} |
|
1872
|
if (s->lookahead == 0) break; /* flush the current block */ |
|
1873
|
} |
|
1874
|
|
|
1875
|
/* Insert the string window[strstart .. strstart + 2] in the |
|
1876
|
* dictionary, and set hash_head to the head of the hash chain: |
|
1877
|
*/ |
|
1878
|
hash_head = NIL; |
|
1879
|
if (s->lookahead >= MIN_MATCH) { |
|
1880
|
INSERT_STRING(s, s->strstart, hash_head); |
|
1881
|
} |
|
1882
|
|
|
1883
|
/* Find the longest match, discarding those <= prev_length. |
|
1884
|
* At this point we have always match_length < MIN_MATCH |
|
1885
|
*/ |
|
1886
|
if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) { |
|
1887
|
/* To simplify the code, we prevent matches with the string |
|
1888
|
* of window index 0 (in particular we have to avoid a match |
|
1889
|
* of the string with itself at the start of the input file). |
|
1890
|
*/ |
|
1891
|
s->match_length = longest_match (s, hash_head); |
|
1892
|
/* longest_match() sets match_start */ |
|
1893
|
} |
|
1894
|
if (s->match_length >= MIN_MATCH) { |
|
1895
|
check_match(s, s->strstart, s->match_start, (int)s->match_length); |
|
1896
|
|
|
1897
|
_tr_tally_dist(s, s->strstart - s->match_start, |
|
1898
|
s->match_length - MIN_MATCH, bflush); |
|
1899
|
|
|
1900
|
s->lookahead -= s->match_length; |
|
1901
|
|
|
1902
|
/* Insert new strings in the hash table only if the match length |
|
1903
|
* is not too large. This saves time but degrades compression. |
|
1904
|
*/ |
|
1905
|
#ifndef FASTEST |
|
1906
|
if (s->match_length <= s->max_insert_length && |
|
1907
|
s->lookahead >= MIN_MATCH) { |
|
1908
|
s->match_length--; /* string at strstart already in table */ |
|
1909
|
do { |
|
1910
|
s->strstart++; |
|
1911
|
INSERT_STRING(s, s->strstart, hash_head); |
|
1912
|
/* strstart never exceeds WSIZE-MAX_MATCH, so there are |
|
1913
|
* always MIN_MATCH bytes ahead. |
|
1914
|
*/ |
|
1915
|
} while (--s->match_length != 0); |
|
1916
|
s->strstart++; |
|
1917
|
} else |
|
1918
|
#endif |
|
1919
|
{ |
|
1920
|
s->strstart += s->match_length; |
|
1921
|
s->match_length = 0; |
|
1922
|
s->ins_h = s->window[s->strstart]; |
|
1923
|
UPDATE_HASH(s, s->ins_h, s->window[s->strstart + 1]); |
|
1924
|
#if MIN_MATCH != 3 |
|
1925
|
Call UPDATE_HASH() MIN_MATCH-3 more times |
|
1926
|
#endif |
|
1927
|
/* If lookahead < MIN_MATCH, ins_h is garbage, but it does not |
|
1928
|
* matter since it will be recomputed at next deflate call. |
|
1929
|
*/ |
|
1930
|
} |
|
1931
|
} else { |
|
1932
|
/* No match, output a literal byte */ |
|
1933
|
Tracevv((stderr,"%c", s->window[s->strstart])); |
|
1934
|
_tr_tally_lit(s, s->window[s->strstart], bflush); |
|
1935
|
s->lookahead--; |
|
1936
|
s->strstart++; |
|
1937
|
} |
|
1938
|
if (bflush) FLUSH_BLOCK(s, 0); |
|
1939
|
} |
|
1940
|
s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; |
|
1941
|
if (flush == Z_FINISH) { |
|
1942
|
FLUSH_BLOCK(s, 1); |
|
1943
|
return finish_done; |
|
1944
|
} |
|
1945
|
if (s->sym_next) |
|
1946
|
FLUSH_BLOCK(s, 0); |
|
1947
|
return block_done; |
|
1948
|
} |
|
1949
|
|
|
1950
|
#ifndef FASTEST |
|
1951
|
/* =========================================================================== |
|
1952
|
* Same as above, but achieves better compression. We use a lazy |
|
1953
|
* evaluation for matches: a match is finally adopted only if there is |
|
1954
|
* no better match at the next window position. |
|
1955
|
*/ |
|
1956
|
local block_state deflate_slow(deflate_state *s, int flush) { |
|
1957
|
IPos hash_head; /* head of hash chain */ |
|
1958
|
int bflush; /* set if current block must be flushed */ |
|
1959
|
|
|
1960
|
/* Process the input block. */ |
|
1961
|
for (;;) { |
|
1962
|
/* Make sure that we always have enough lookahead, except |
|
1963
|
* at the end of the input file. We need MAX_MATCH bytes |
|
1964
|
* for the next match, plus MIN_MATCH bytes to insert the |
|
1965
|
* string following the next match. |
|
1966
|
*/ |
|
1967
|
if (s->lookahead < MIN_LOOKAHEAD) { |
|
1968
|
fill_window(s); |
|
1969
|
if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) { |
|
1970
|
return need_more; |
|
1971
|
} |
|
1972
|
if (s->lookahead == 0) break; /* flush the current block */ |
|
1973
|
} |
|
1974
|
|
|
1975
|
/* Insert the string window[strstart .. strstart + 2] in the |
|
1976
|
* dictionary, and set hash_head to the head of the hash chain: |
|
1977
|
*/ |
|
1978
|
hash_head = NIL; |
|
1979
|
if (s->lookahead >= MIN_MATCH) { |
|
1980
|
INSERT_STRING(s, s->strstart, hash_head); |
|
1981
|
} |
|
1982
|
|
|
1983
|
/* Find the longest match, discarding those <= prev_length. |
|
1984
|
*/ |
|
1985
|
s->prev_length = s->match_length, s->prev_match = s->match_start; |
|
1986
|
s->match_length = MIN_MATCH-1; |
|
1987
|
|
|
1988
|
if (hash_head != NIL && s->prev_length < s->max_lazy_match && |
|
1989
|
s->strstart - hash_head <= MAX_DIST(s)) { |
|
1990
|
/* To simplify the code, we prevent matches with the string |
|
1991
|
* of window index 0 (in particular we have to avoid a match |
|
1992
|
* of the string with itself at the start of the input file). |
|
1993
|
*/ |
|
1994
|
s->match_length = longest_match (s, hash_head); |
|
1995
|
/* longest_match() sets match_start */ |
|
1996
|
|
|
1997
|
if (s->match_length <= 5 && (s->strategy == Z_FILTERED |
|
1998
|
#if TOO_FAR <= 32767 |
|
1999
|
|| (s->match_length == MIN_MATCH && |
|
2000
|
s->strstart - s->match_start > TOO_FAR) |
|
2001
|
#endif |
|
2002
|
)) { |
|
2003
|
|
|
2004
|
/* If prev_match is also MIN_MATCH, match_start is garbage |
|
2005
|
* but we will ignore the current match anyway. |
|
2006
|
*/ |
|
2007
|
s->match_length = MIN_MATCH-1; |
|
2008
|
} |
|
2009
|
} |
|
2010
|
/* If there was a match at the previous step and the current |
|
2011
|
* match is not better, output the previous match: |
|
2012
|
*/ |
|
2013
|
if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) { |
|
2014
|
uInt max_insert = s->strstart + s->lookahead - MIN_MATCH; |
|
2015
|
/* Do not insert strings in hash table beyond this. */ |
|
2016
|
|
|
2017
|
check_match(s, s->strstart - 1, s->prev_match, (int)s->prev_length); |
|
2018
|
|
|
2019
|
_tr_tally_dist(s, s->strstart - 1 - s->prev_match, |
|
2020
|
s->prev_length - MIN_MATCH, bflush); |
|
2021
|
|
|
2022
|
/* Insert in hash table all strings up to the end of the match. |
|
2023
|
* strstart - 1 and strstart are already inserted. If there is not |
|
2024
|
* enough lookahead, the last two strings are not inserted in |
|
2025
|
* the hash table. |
|
2026
|
*/ |
|
2027
|
s->lookahead -= s->prev_length - 1; |
|
2028
|
s->prev_length -= 2; |
|
2029
|
do { |
|
2030
|
if (++s->strstart <= max_insert) { |
|
2031
|
INSERT_STRING(s, s->strstart, hash_head); |
|
2032
|
} |
|
2033
|
} while (--s->prev_length != 0); |
|
2034
|
s->match_available = 0; |
|
2035
|
s->match_length = MIN_MATCH-1; |
|
2036
|
s->strstart++; |
|
2037
|
|
|
2038
|
if (bflush) FLUSH_BLOCK(s, 0); |
|
2039
|
|
|
2040
|
} else if (s->match_available) { |
|
2041
|
/* If there was no match at the previous position, output a |
|
2042
|
* single literal. If there was a match but the current match |
|
2043
|
* is longer, truncate the previous match to a single literal. |
|
2044
|
*/ |
|
2045
|
Tracevv((stderr,"%c", s->window[s->strstart - 1])); |
|
2046
|
_tr_tally_lit(s, s->window[s->strstart - 1], bflush); |
|
2047
|
if (bflush) { |
|
2048
|
FLUSH_BLOCK_ONLY(s, 0); |
|
2049
|
} |
|
2050
|
s->strstart++; |
|
2051
|
s->lookahead--; |
|
2052
|
if (s->strm->avail_out == 0) return need_more; |
|
2053
|
} else { |
|
2054
|
/* There is no previous match to compare with, wait for |
|
2055
|
* the next step to decide. |
|
2056
|
*/ |
|
2057
|
s->match_available = 1; |
|
2058
|
s->strstart++; |
|
2059
|
s->lookahead--; |
|
2060
|
} |
|
2061
|
} |
|
2062
|
Assert (flush != Z_NO_FLUSH, "no flush?"); |
|
2063
|
if (s->match_available) { |
|
2064
|
Tracevv((stderr,"%c", s->window[s->strstart - 1])); |
|
2065
|
_tr_tally_lit(s, s->window[s->strstart - 1], bflush); |
|
2066
|
s->match_available = 0; |
|
2067
|
} |
|
2068
|
s->insert = s->strstart < MIN_MATCH-1 ? s->strstart : MIN_MATCH-1; |
|
2069
|
if (flush == Z_FINISH) { |
|
2070
|
FLUSH_BLOCK(s, 1); |
|
2071
|
return finish_done; |
|
2072
|
} |
|
2073
|
if (s->sym_next) |
|
2074
|
FLUSH_BLOCK(s, 0); |
|
2075
|
return block_done; |
|
2076
|
} |
|
2077
|
#endif /* FASTEST */ |
|
2078
|
|
|
2079
|
/* =========================================================================== |
|
2080
|
* For Z_RLE, simply look for runs of bytes, generate matches only of distance |
|
2081
|
* one. Do not maintain a hash table. (It will be regenerated if this run of |
|
2082
|
* deflate switches away from Z_RLE.) |
|
2083
|
*/ |
|
2084
|
local block_state deflate_rle(deflate_state *s, int flush) { |
|
2085
|
int bflush; /* set if current block must be flushed */ |
|
2086
|
uInt prev; /* byte at distance one to match */ |
|
2087
|
Bytef *scan, *strend; /* scan goes up to strend for length of run */ |
|
2088
|
|
|
2089
|
for (;;) { |
|
2090
|
/* Make sure that we always have enough lookahead, except |
|
2091
|
* at the end of the input file. We need MAX_MATCH bytes |
|
2092
|
* for the longest run, plus one for the unrolled loop. |
|
2093
|
*/ |
|
2094
|
if (s->lookahead <= MAX_MATCH) { |
|
2095
|
fill_window(s); |
|
2096
|
if (s->lookahead <= MAX_MATCH && flush == Z_NO_FLUSH) { |
|
2097
|
return need_more; |
|
2098
|
} |
|
2099
|
if (s->lookahead == 0) break; /* flush the current block */ |
|
2100
|
} |
|
2101
|
|
|
2102
|
/* See how many times the previous byte repeats */ |
|
2103
|
s->match_length = 0; |
|
2104
|
if (s->lookahead >= MIN_MATCH && s->strstart > 0) { |
|
2105
|
scan = s->window + s->strstart - 1; |
|
2106
|
prev = *scan; |
|
2107
|
if (prev == *++scan && prev == *++scan && prev == *++scan) { |
|
2108
|
strend = s->window + s->strstart + MAX_MATCH; |
|
2109
|
do { |
|
2110
|
} while (prev == *++scan && prev == *++scan && |
|
2111
|
prev == *++scan && prev == *++scan && |
|
2112
|
prev == *++scan && prev == *++scan && |
|
2113
|
prev == *++scan && prev == *++scan && |
|
2114
|
scan < strend); |
|
2115
|
s->match_length = MAX_MATCH - (uInt)(strend - scan); |
|
2116
|
if (s->match_length > s->lookahead) |
|
2117
|
s->match_length = s->lookahead; |
|
2118
|
} |
|
2119
|
Assert(scan <= s->window + (uInt)(s->window_size - 1), |
|
2120
|
"wild scan"); |
|
2121
|
} |
|
2122
|
|
|
2123
|
/* Emit match if have run of MIN_MATCH or longer, else emit literal */ |
|
2124
|
if (s->match_length >= MIN_MATCH) { |
|
2125
|
check_match(s, s->strstart, s->strstart - 1, (int)s->match_length); |
|
2126
|
|
|
2127
|
_tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush); |
|
2128
|
|
|
2129
|
s->lookahead -= s->match_length; |
|
2130
|
s->strstart += s->match_length; |
|
2131
|
s->match_length = 0; |
|
2132
|
} else { |
|
2133
|
/* No match, output a literal byte */ |
|
2134
|
Tracevv((stderr,"%c", s->window[s->strstart])); |
|
2135
|
_tr_tally_lit(s, s->window[s->strstart], bflush); |
|
2136
|
s->lookahead--; |
|
2137
|
s->strstart++; |
|
2138
|
} |
|
2139
|
if (bflush) FLUSH_BLOCK(s, 0); |
|
2140
|
} |
|
2141
|
s->insert = 0; |
|
2142
|
if (flush == Z_FINISH) { |
|
2143
|
FLUSH_BLOCK(s, 1); |
|
2144
|
return finish_done; |
|
2145
|
} |
|
2146
|
if (s->sym_next) |
|
2147
|
FLUSH_BLOCK(s, 0); |
|
2148
|
return block_done; |
|
2149
|
} |
|
2150
|
|
|
2151
|
/* =========================================================================== |
|
2152
|
* For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table. |
|
2153
|
* (It will be regenerated if this run of deflate switches away from Huffman.) |
|
2154
|
*/ |
|
2155
|
local block_state deflate_huff(deflate_state *s, int flush) { |
|
2156
|
int bflush; /* set if current block must be flushed */ |
|
2157
|
|
|
2158
|
for (;;) { |
|
2159
|
/* Make sure that we have a literal to write. */ |
|
2160
|
if (s->lookahead == 0) { |
|
2161
|
fill_window(s); |
|
2162
|
if (s->lookahead == 0) { |
|
2163
|
if (flush == Z_NO_FLUSH) |
|
2164
|
return need_more; |
|
2165
|
break; /* flush the current block */ |
|
2166
|
} |
|
2167
|
} |
|
2168
|
|
|
2169
|
/* Output a literal byte */ |
|
2170
|
s->match_length = 0; |
|
2171
|
Tracevv((stderr,"%c", s->window[s->strstart])); |
|
2172
|
_tr_tally_lit(s, s->window[s->strstart], bflush); |
|
2173
|
s->lookahead--; |
|
2174
|
s->strstart++; |
|
2175
|
if (bflush) FLUSH_BLOCK(s, 0); |
|
2176
|
} |
|
2177
|
s->insert = 0; |
|
2178
|
if (flush == Z_FINISH) { |
|
2179
|
FLUSH_BLOCK(s, 1); |
|
2180
|
return finish_done; |
|
2181
|
} |
|
2182
|
if (s->sym_next) |
|
2183
|
FLUSH_BLOCK(s, 0); |
|
2184
|
return block_done; |
|
2185
|
} |
|
2186
|
|