Andy Green | f431247 | 2013-01-19 15:11:23 +0800 | [diff] [blame] | 1 | /* deflate.c -- compress data using the deflation algorithm
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| 2 | * Copyright (C) 1995-2010 Jean-loup Gailly and Mark Adler
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| 3 | * For conditions of distribution and use, see copyright notice in zlib.h
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| 4 | */
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| 5 |
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| 6 | /*
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| 7 | * ALGORITHM
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| 8 | *
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| 9 | * The "deflation" process depends on being able to identify portions
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| 10 | * of the input text which are identical to earlier input (within a
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| 11 | * sliding window trailing behind the input currently being processed).
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| 12 | *
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| 13 | * The most straightforward technique turns out to be the fastest for
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| 14 | * most input files: try all possible matches and select the longest.
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| 15 | * The key feature of this algorithm is that insertions into the string
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| 16 | * dictionary are very simple and thus fast, and deletions are avoided
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| 17 | * completely. Insertions are performed at each input character, whereas
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| 18 | * string matches are performed only when the previous match ends. So it
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| 19 | * is preferable to spend more time in matches to allow very fast string
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| 20 | * insertions and avoid deletions. The matching algorithm for small
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| 21 | * strings is inspired from that of Rabin & Karp. A brute force approach
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| 22 | * is used to find longer strings when a small match has been found.
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| 23 | * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
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| 24 | * (by Leonid Broukhis).
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| 25 | * A previous version of this file used a more sophisticated algorithm
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| 26 | * (by Fiala and Greene) which is guaranteed to run in linear amortized
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| 27 | * time, but has a larger average cost, uses more memory and is patented.
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| 28 | * However the F&G algorithm may be faster for some highly redundant
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| 29 | * files if the parameter max_chain_length (described below) is too large.
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| 30 | *
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| 31 | * ACKNOWLEDGEMENTS
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| 32 | *
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| 33 | * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
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| 34 | * I found it in 'freeze' written by Leonid Broukhis.
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| 35 | * Thanks to many people for bug reports and testing.
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| 36 | *
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| 37 | * REFERENCES
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| 38 | *
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| 39 | * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
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| 40 | * Available in http://www.ietf.org/rfc/rfc1951.txt
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| 41 | *
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| 42 | * A description of the Rabin and Karp algorithm is given in the book
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| 43 | * "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
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| 44 | *
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| 45 | * Fiala,E.R., and Greene,D.H.
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| 46 | * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
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| 47 | *
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| 48 | */
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| 49 |
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| 50 | /* @(#) $Id$ */
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| 51 |
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| 52 | #include "deflate.h"
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| 53 |
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| 54 | const char deflate_copyright[] =
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| 55 | " deflate 1.2.5 Copyright 1995-2010 Jean-loup Gailly and Mark Adler ";
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| 56 | /*
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| 57 | If you use the zlib library in a product, an acknowledgment is welcome
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| 58 | in the documentation of your product. If for some reason you cannot
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| 59 | include such an acknowledgment, I would appreciate that you keep this
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| 60 | copyright string in the executable of your product.
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| 61 | */
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| 62 |
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| 63 | /* ===========================================================================
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| 64 | * Function prototypes.
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| 65 | */
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| 66 | typedef enum {
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| 67 | need_more, /* block not completed, need more input or more output */
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| 68 | block_done, /* block flush performed */
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| 69 | finish_started, /* finish started, need only more output at next deflate */
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| 70 | finish_done /* finish done, accept no more input or output */
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| 71 | } block_state;
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| 72 |
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| 73 | typedef block_state (*compress_func) OF((deflate_state *s, int flush));
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| 74 | /* Compression function. Returns the block state after the call. */
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| 75 |
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| 76 | local void fill_window OF((deflate_state *s));
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| 77 | local block_state deflate_stored OF((deflate_state *s, int flush));
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| 78 | local block_state deflate_fast OF((deflate_state *s, int flush));
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| 79 | #ifndef FASTEST
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| 80 | local block_state deflate_slow OF((deflate_state *s, int flush));
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| 81 | #endif
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| 82 | local block_state deflate_rle OF((deflate_state *s, int flush));
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| 83 | local block_state deflate_huff OF((deflate_state *s, int flush));
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| 84 | local void lm_init OF((deflate_state *s));
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| 85 | local void putShortMSB OF((deflate_state *s, uInt b));
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| 86 | local void flush_pending OF((z_streamp strm));
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| 87 | local int read_buf OF((z_streamp strm, Bytef *buf, unsigned size));
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| 88 | #ifdef ASMV
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| 89 | void match_init OF((void)); /* asm code initialization */
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| 90 | uInt longest_match OF((deflate_state *s, IPos cur_match));
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| 91 | #else
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| 92 | local uInt longest_match OF((deflate_state *s, IPos cur_match));
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| 93 | #endif
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| 94 |
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| 95 | #ifdef DEBUG
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| 96 | local void check_match OF((deflate_state *s, IPos start, IPos match,
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| 97 | int length));
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| 98 | #endif
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| 99 |
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| 100 | /* ===========================================================================
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| 101 | * Local data
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| 102 | */
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| 103 |
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| 104 | #define NIL 0
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| 105 | /* Tail of hash chains */
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| 106 |
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| 107 | #ifndef TOO_FAR
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| 108 | # define TOO_FAR 4096
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| 109 | #endif
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| 110 | /* Matches of length 3 are discarded if their distance exceeds TOO_FAR */
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| 111 |
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| 112 | /* Values for max_lazy_match, good_match and max_chain_length, depending on
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| 113 | * the desired pack level (0..9). The values given below have been tuned to
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| 114 | * exclude worst case performance for pathological files. Better values may be
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| 115 | * found for specific files.
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| 116 | */
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| 117 | typedef struct config_s {
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| 118 | ush good_length; /* reduce lazy search above this match length */
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| 119 | ush max_lazy; /* do not perform lazy search above this match length */
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| 120 | ush nice_length; /* quit search above this match length */
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| 121 | ush max_chain;
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| 122 | compress_func func;
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| 123 | } config;
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| 124 |
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| 125 | #ifdef FASTEST
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| 126 | local const config configuration_table[2] = {
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| 127 | /* good lazy nice chain */
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| 128 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
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| 129 | /* 1 */ {4, 4, 8, 4, deflate_fast}}; /* max speed, no lazy matches */
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| 130 | #else
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| 131 | local const config configuration_table[10] = {
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| 132 | /* good lazy nice chain */
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| 133 | /* 0 */ {0, 0, 0, 0, deflate_stored}, /* store only */
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| 134 | /* 1 */ {4, 4, 8, 4, deflate_fast}, /* max speed, no lazy matches */
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| 135 | /* 2 */ {4, 5, 16, 8, deflate_fast},
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| 136 | /* 3 */ {4, 6, 32, 32, deflate_fast},
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| 137 |
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| 138 | /* 4 */ {4, 4, 16, 16, deflate_slow}, /* lazy matches */
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| 139 | /* 5 */ {8, 16, 32, 32, deflate_slow},
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| 140 | /* 6 */ {8, 16, 128, 128, deflate_slow},
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| 141 | /* 7 */ {8, 32, 128, 256, deflate_slow},
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| 142 | /* 8 */ {32, 128, 258, 1024, deflate_slow},
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| 143 | /* 9 */ {32, 258, 258, 4096, deflate_slow}}; /* max compression */
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| 144 | #endif
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| 145 |
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| 146 | /* Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
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| 147 | * For deflate_fast() (levels <= 3) good is ignored and lazy has a different
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| 148 | * meaning.
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| 149 | */
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| 150 |
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| 151 | #define EQUAL 0
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| 152 | /* result of memcmp for equal strings */
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| 153 |
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| 154 | #ifndef NO_DUMMY_DECL
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| 155 | struct static_tree_desc_s {int dummy;}; /* for buggy compilers */
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| 156 | #endif
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| 157 |
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| 158 | /* ===========================================================================
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| 159 | * Update a hash value with the given input byte
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| 160 | * IN assertion: all calls to to UPDATE_HASH are made with consecutive
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| 161 | * input characters, so that a running hash key can be computed from the
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| 162 | * previous key instead of complete recalculation each time.
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| 163 | */
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| 164 | #define UPDATE_HASH(s,h,c) (h = (((h)<<s->hash_shift) ^ (c)) & s->hash_mask)
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| 165 |
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| 166 |
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| 167 | /* ===========================================================================
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| 168 | * Insert string str in the dictionary and set match_head to the previous head
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| 169 | * of the hash chain (the most recent string with same hash key). Return
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| 170 | * the previous length of the hash chain.
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| 171 | * If this file is compiled with -DFASTEST, the compression level is forced
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| 172 | * to 1, and no hash chains are maintained.
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| 173 | * IN assertion: all calls to to INSERT_STRING are made with consecutive
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| 174 | * input characters and the first MIN_MATCH bytes of str are valid
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| 175 | * (except for the last MIN_MATCH-1 bytes of the input file).
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| 176 | */
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| 177 | #ifdef FASTEST
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| 178 | #define INSERT_STRING(s, str, match_head) \
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| 179 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
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| 180 | match_head = s->head[s->ins_h], \
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| 181 | s->head[s->ins_h] = (Pos)(str))
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| 182 | #else
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| 183 | #define INSERT_STRING(s, str, match_head) \
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| 184 | (UPDATE_HASH(s, s->ins_h, s->window[(str) + (MIN_MATCH-1)]), \
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| 185 | match_head = s->prev[(str) & s->w_mask] = s->head[s->ins_h], \
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| 186 | s->head[s->ins_h] = (Pos)(str))
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| 187 | #endif
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| 188 |
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| 189 | /* ===========================================================================
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| 190 | * Initialize the hash table (avoiding 64K overflow for 16 bit systems).
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| 191 | * prev[] will be initialized on the fly.
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| 192 | */
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| 193 | #define CLEAR_HASH(s) \
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| 194 | s->head[s->hash_size-1] = NIL; \
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| 195 | zmemzero((Bytef *)s->head, (unsigned)(s->hash_size-1)*sizeof(*s->head));
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| 196 |
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| 197 | /* ========================================================================= */
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| 198 | int ZEXPORT deflateInit_(strm, level, version, stream_size)
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| 199 | z_streamp strm;
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| 200 | int level;
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| 201 | const char *version;
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| 202 | int stream_size;
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| 203 | {
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| 204 | return deflateInit2_(strm, level, Z_DEFLATED, MAX_WBITS, DEF_MEM_LEVEL,
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| 205 | Z_DEFAULT_STRATEGY, version, stream_size);
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| 206 | /* To do: ignore strm->next_in if we use it as window */
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| 207 | }
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| 208 |
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| 209 | /* ========================================================================= */
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| 210 | int ZEXPORT deflateInit2_(strm, level, method, windowBits, memLevel, strategy,
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| 211 | version, stream_size)
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| 212 | z_streamp strm;
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| 213 | int level;
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| 214 | int method;
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| 215 | int windowBits;
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| 216 | int memLevel;
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| 217 | int strategy;
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| 218 | const char *version;
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| 219 | int stream_size;
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| 220 | {
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| 221 | deflate_state *s;
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| 222 | int wrap = 1;
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| 223 | static const char my_version[] = ZLIB_VERSION;
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| 224 |
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| 225 | ushf *overlay;
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| 226 | /* We overlay pending_buf and d_buf+l_buf. This works since the average
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| 227 | * output size for (length,distance) codes is <= 24 bits.
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| 228 | */
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| 229 |
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| 230 | if (version == Z_NULL || version[0] != my_version[0] ||
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| 231 | stream_size != sizeof(z_stream)) {
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| 232 | return Z_VERSION_ERROR;
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| 233 | }
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| 234 | if (strm == Z_NULL) return Z_STREAM_ERROR;
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| 235 |
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| 236 | strm->msg = Z_NULL;
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| 237 | if (strm->zalloc == (alloc_func)0) {
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| 238 | strm->zalloc = zcalloc;
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| 239 | strm->opaque = (voidpf)0;
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| 240 | }
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| 241 | if (strm->zfree == (free_func)0) strm->zfree = zcfree;
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| 242 |
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| 243 | #ifdef FASTEST
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| 244 | if (level != 0) level = 1;
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| 245 | #else
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| 246 | if (level == Z_DEFAULT_COMPRESSION) level = 6;
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| 247 | #endif
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| 248 |
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| 249 | if (windowBits < 0) { /* suppress zlib wrapper */
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| 250 | wrap = 0;
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| 251 | windowBits = -windowBits;
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| 252 | }
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| 253 | #ifdef GZIP
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| 254 | else if (windowBits > 15) {
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| 255 | wrap = 2; /* write gzip wrapper instead */
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| 256 | windowBits -= 16;
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| 257 | }
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| 258 | #endif
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| 259 | if (memLevel < 1 || memLevel > MAX_MEM_LEVEL || method != Z_DEFLATED ||
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| 260 | windowBits < 8 || windowBits > 15 || level < 0 || level > 9 ||
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| 261 | strategy < 0 || strategy > Z_FIXED) {
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| 262 | return Z_STREAM_ERROR;
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| 263 | }
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| 264 | if (windowBits == 8) windowBits = 9; /* until 256-byte window bug fixed */
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| 265 | s = (deflate_state *) ZALLOC(strm, 1, sizeof(deflate_state));
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| 266 | if (s == Z_NULL) return Z_MEM_ERROR;
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| 267 | strm->state = (struct internal_state FAR *)s;
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| 268 | s->strm = strm;
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| 269 |
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| 270 | s->wrap = wrap;
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| 271 | s->gzhead = Z_NULL;
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| 272 | s->w_bits = windowBits;
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| 273 | s->w_size = 1 << s->w_bits;
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| 274 | s->w_mask = s->w_size - 1;
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| 275 |
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| 276 | s->hash_bits = memLevel + 7;
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| 277 | s->hash_size = 1 << s->hash_bits;
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| 278 | s->hash_mask = s->hash_size - 1;
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| 279 | s->hash_shift = ((s->hash_bits+MIN_MATCH-1)/MIN_MATCH);
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| 280 |
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| 281 | s->window = (Bytef *) ZALLOC(strm, s->w_size, 2*sizeof(Byte));
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| 282 | s->prev = (Posf *) ZALLOC(strm, s->w_size, sizeof(Pos));
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| 283 | s->head = (Posf *) ZALLOC(strm, s->hash_size, sizeof(Pos));
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| 284 |
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| 285 | s->high_water = 0; /* nothing written to s->window yet */
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| 286 |
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| 287 | s->lit_bufsize = 1 << (memLevel + 6); /* 16K elements by default */
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| 288 |
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| 289 | overlay = (ushf *) ZALLOC(strm, s->lit_bufsize, sizeof(ush)+2);
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| 290 | s->pending_buf = (uchf *) overlay;
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| 291 | s->pending_buf_size = (ulg)s->lit_bufsize * (sizeof(ush)+2L);
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| 292 |
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| 293 | if (s->window == Z_NULL || s->prev == Z_NULL || s->head == Z_NULL ||
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| 294 | s->pending_buf == Z_NULL) {
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| 295 | s->status = FINISH_STATE;
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| 296 | strm->msg = (char*)ERR_MSG(Z_MEM_ERROR);
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| 297 | deflateEnd (strm);
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| 298 | return Z_MEM_ERROR;
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| 299 | }
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| 300 | s->d_buf = overlay + s->lit_bufsize/sizeof(ush);
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| 301 | s->l_buf = s->pending_buf + (1+sizeof(ush))*s->lit_bufsize;
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| 302 |
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| 303 | s->level = level;
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| 304 | s->strategy = strategy;
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| 305 | s->method = (Byte)method;
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| 306 |
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| 307 | return deflateReset(strm);
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| 308 | }
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| 309 |
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| 310 | /* ========================================================================= */
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| 311 | int ZEXPORT deflateSetDictionary (strm, dictionary, dictLength)
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| 312 | z_streamp strm;
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| 313 | const Bytef *dictionary;
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| 314 | uInt dictLength;
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| 315 | {
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| 316 | deflate_state *s;
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| 317 | uInt length = dictLength;
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| 318 | uInt n;
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| 319 | IPos hash_head = 0;
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| 320 |
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| 321 | if (strm == Z_NULL || strm->state == Z_NULL || dictionary == Z_NULL ||
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| 322 | strm->state->wrap == 2 ||
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| 323 | (strm->state->wrap == 1 && strm->state->status != INIT_STATE))
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| 324 | return Z_STREAM_ERROR;
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| 325 |
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| 326 | s = strm->state;
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| 327 | if (s->wrap)
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| 328 | strm->adler = adler32(strm->adler, dictionary, dictLength);
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| 329 |
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| 330 | if (length < MIN_MATCH) return Z_OK;
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| 331 | if (length > s->w_size) {
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| 332 | length = s->w_size;
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| 333 | dictionary += dictLength - length; /* use the tail of the dictionary */
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| 334 | }
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| 335 | zmemcpy(s->window, dictionary, length);
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| 336 | s->strstart = length;
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| 337 | s->block_start = (long)length;
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| 338 |
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| 339 | /* Insert all strings in the hash table (except for the last two bytes).
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| 340 | * s->lookahead stays null, so s->ins_h will be recomputed at the next
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| 341 | * call of fill_window.
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| 342 | */
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| 343 | s->ins_h = s->window[0];
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| 344 | UPDATE_HASH(s, s->ins_h, s->window[1]);
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| 345 | for (n = 0; n <= length - MIN_MATCH; n++) {
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| 346 | INSERT_STRING(s, n, hash_head);
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| 347 | }
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| 348 | if (hash_head) hash_head = 0; /* to make compiler happy */
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| 349 | return Z_OK;
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| 350 | }
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| 351 |
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| 352 | /* ========================================================================= */
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| 353 | int ZEXPORT deflateReset (strm)
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| 354 | z_streamp strm;
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| 355 | {
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| 356 | deflate_state *s;
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| 357 |
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| 358 | if (strm == Z_NULL || strm->state == Z_NULL ||
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| 359 | strm->zalloc == (alloc_func)0 || strm->zfree == (free_func)0) {
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| 360 | return Z_STREAM_ERROR;
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| 361 | }
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| 362 |
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| 363 | strm->total_in = strm->total_out = 0;
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| 364 | strm->msg = Z_NULL; /* use zfree if we ever allocate msg dynamically */
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| 365 | strm->data_type = Z_UNKNOWN;
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| 366 |
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| 367 | s = (deflate_state *)strm->state;
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| 368 | s->pending = 0;
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| 369 | s->pending_out = s->pending_buf;
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| 370 |
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| 371 | if (s->wrap < 0) {
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| 372 | s->wrap = -s->wrap; /* was made negative by deflate(..., Z_FINISH); */
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| 373 | }
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| 374 | s->status = s->wrap ? INIT_STATE : BUSY_STATE;
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| 375 | strm->adler =
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| 376 | #ifdef GZIP
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| 377 | s->wrap == 2 ? crc32(0L, Z_NULL, 0) :
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| 378 | #endif
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| 379 | adler32(0L, Z_NULL, 0);
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| 380 | s->last_flush = Z_NO_FLUSH;
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| 381 |
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| 382 | _tr_init(s);
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| 383 | lm_init(s);
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| 384 |
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| 385 | return Z_OK;
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| 386 | }
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| 387 |
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| 388 | /* ========================================================================= */
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| 389 | int ZEXPORT deflateSetHeader (strm, head)
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| 390 | z_streamp strm;
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| 391 | gz_headerp head;
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| 392 | {
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| 393 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
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| 394 | if (strm->state->wrap != 2) return Z_STREAM_ERROR;
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| 395 | strm->state->gzhead = head;
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| 396 | return Z_OK;
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| 397 | }
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| 398 |
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| 399 | /* ========================================================================= */
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| 400 | int ZEXPORT deflatePrime (strm, bits, value)
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| 401 | z_streamp strm;
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| 402 | int bits;
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| 403 | int value;
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| 404 | {
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| 405 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
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| 406 | strm->state->bi_valid = bits;
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| 407 | strm->state->bi_buf = (ush)(value & ((1 << bits) - 1));
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| 408 | return Z_OK;
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| 409 | }
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| 410 |
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| 411 | /* ========================================================================= */
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| 412 | int ZEXPORT deflateParams(strm, level, strategy)
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| 413 | z_streamp strm;
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| 414 | int level;
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| 415 | int strategy;
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| 416 | {
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| 417 | deflate_state *s;
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| 418 | compress_func func;
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| 419 | int err = Z_OK;
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| 420 |
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| 421 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
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| 422 | s = strm->state;
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| 423 |
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| 424 | #ifdef FASTEST
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| 425 | if (level != 0) level = 1;
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| 426 | #else
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| 427 | if (level == Z_DEFAULT_COMPRESSION) level = 6;
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| 428 | #endif
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| 429 | if (level < 0 || level > 9 || strategy < 0 || strategy > Z_FIXED) {
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| 430 | return Z_STREAM_ERROR;
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| 431 | }
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| 432 | func = configuration_table[s->level].func;
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| 433 |
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| 434 | if ((strategy != s->strategy || func != configuration_table[level].func) &&
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| 435 | strm->total_in != 0) {
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| 436 | /* Flush the last buffer: */
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| 437 | err = deflate(strm, Z_BLOCK);
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| 438 | }
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| 439 | if (s->level != level) {
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| 440 | s->level = level;
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| 441 | s->max_lazy_match = configuration_table[level].max_lazy;
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| 442 | s->good_match = configuration_table[level].good_length;
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| 443 | s->nice_match = configuration_table[level].nice_length;
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| 444 | s->max_chain_length = configuration_table[level].max_chain;
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| 445 | }
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| 446 | s->strategy = strategy;
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| 447 | return err;
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| 448 | }
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| 449 |
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| 450 | /* ========================================================================= */
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| 451 | int ZEXPORT deflateTune(strm, good_length, max_lazy, nice_length, max_chain)
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| 452 | z_streamp strm;
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| 453 | int good_length;
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| 454 | int max_lazy;
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| 455 | int nice_length;
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| 456 | int max_chain;
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| 457 | {
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| 458 | deflate_state *s;
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| 459 |
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| 460 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
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| 461 | s = strm->state;
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| 462 | s->good_match = good_length;
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| 463 | s->max_lazy_match = max_lazy;
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| 464 | s->nice_match = nice_length;
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| 465 | s->max_chain_length = max_chain;
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| 466 | return Z_OK;
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| 467 | }
|
| 468 |
|
| 469 | /* =========================================================================
|
| 470 | * For the default windowBits of 15 and memLevel of 8, this function returns
|
| 471 | * a close to exact, as well as small, upper bound on the compressed size.
|
| 472 | * They are coded as constants here for a reason--if the #define's are
|
| 473 | * changed, then this function needs to be changed as well. The return
|
| 474 | * value for 15 and 8 only works for those exact settings.
|
| 475 | *
|
| 476 | * For any setting other than those defaults for windowBits and memLevel,
|
| 477 | * the value returned is a conservative worst case for the maximum expansion
|
| 478 | * resulting from using fixed blocks instead of stored blocks, which deflate
|
| 479 | * can emit on compressed data for some combinations of the parameters.
|
| 480 | *
|
| 481 | * This function could be more sophisticated to provide closer upper bounds for
|
| 482 | * every combination of windowBits and memLevel. But even the conservative
|
| 483 | * upper bound of about 14% expansion does not seem onerous for output buffer
|
| 484 | * allocation.
|
| 485 | */
|
| 486 | uLong ZEXPORT deflateBound(strm, sourceLen)
|
| 487 | z_streamp strm;
|
| 488 | uLong sourceLen;
|
| 489 | {
|
| 490 | deflate_state *s;
|
| 491 | uLong complen, wraplen;
|
| 492 | Bytef *str;
|
| 493 |
|
| 494 | /* conservative upper bound for compressed data */
|
| 495 | complen = sourceLen +
|
| 496 | ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5;
|
| 497 |
|
| 498 | /* if can't get parameters, return conservative bound plus zlib wrapper */
|
| 499 | if (strm == Z_NULL || strm->state == Z_NULL)
|
| 500 | return complen + 6;
|
| 501 |
|
| 502 | /* compute wrapper length */
|
| 503 | s = strm->state;
|
| 504 | switch (s->wrap) {
|
| 505 | case 0: /* raw deflate */
|
| 506 | wraplen = 0;
|
| 507 | break;
|
| 508 | case 1: /* zlib wrapper */
|
| 509 | wraplen = 6 + (s->strstart ? 4 : 0);
|
| 510 | break;
|
| 511 | case 2: /* gzip wrapper */
|
| 512 | wraplen = 18;
|
| 513 | if (s->gzhead != Z_NULL) { /* user-supplied gzip header */
|
| 514 | if (s->gzhead->extra != Z_NULL)
|
| 515 | wraplen += 2 + s->gzhead->extra_len;
|
| 516 | str = s->gzhead->name;
|
| 517 | if (str != Z_NULL)
|
| 518 | do {
|
| 519 | wraplen++;
|
| 520 | } while (*str++);
|
| 521 | str = s->gzhead->comment;
|
| 522 | if (str != Z_NULL)
|
| 523 | do {
|
| 524 | wraplen++;
|
| 525 | } while (*str++);
|
| 526 | if (s->gzhead->hcrc)
|
| 527 | wraplen += 2;
|
| 528 | }
|
| 529 | break;
|
| 530 | default: /* for compiler happiness */
|
| 531 | wraplen = 6;
|
| 532 | }
|
| 533 |
|
| 534 | /* if not default parameters, return conservative bound */
|
| 535 | if (s->w_bits != 15 || s->hash_bits != 8 + 7)
|
| 536 | return complen + wraplen;
|
| 537 |
|
| 538 | /* default settings: return tight bound for that case */
|
| 539 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) +
|
| 540 | (sourceLen >> 25) + 13 - 6 + wraplen;
|
| 541 | }
|
| 542 |
|
| 543 | /* =========================================================================
|
| 544 | * Put a short in the pending buffer. The 16-bit value is put in MSB order.
|
| 545 | * IN assertion: the stream state is correct and there is enough room in
|
| 546 | * pending_buf.
|
| 547 | */
|
| 548 | local void putShortMSB (s, b)
|
| 549 | deflate_state *s;
|
| 550 | uInt b;
|
| 551 | {
|
| 552 | put_byte(s, (Byte)(b >> 8));
|
| 553 | put_byte(s, (Byte)(b & 0xff));
|
| 554 | }
|
| 555 |
|
| 556 | /* =========================================================================
|
| 557 | * Flush as much pending output as possible. All deflate() output goes
|
| 558 | * through this function so some applications may wish to modify it
|
| 559 | * to avoid allocating a large strm->next_out buffer and copying into it.
|
| 560 | * (See also read_buf()).
|
| 561 | */
|
| 562 | local void flush_pending(strm)
|
| 563 | z_streamp strm;
|
| 564 | {
|
| 565 | unsigned len = strm->state->pending;
|
| 566 |
|
| 567 | if (len > strm->avail_out) len = strm->avail_out;
|
| 568 | if (len == 0) return;
|
| 569 |
|
| 570 | zmemcpy(strm->next_out, strm->state->pending_out, len);
|
| 571 | strm->next_out += len;
|
| 572 | strm->state->pending_out += len;
|
| 573 | strm->total_out += len;
|
| 574 | strm->avail_out -= len;
|
| 575 | strm->state->pending -= len;
|
| 576 | if (strm->state->pending == 0) {
|
| 577 | strm->state->pending_out = strm->state->pending_buf;
|
| 578 | }
|
| 579 | }
|
| 580 |
|
| 581 | /* ========================================================================= */
|
| 582 | int ZEXPORT deflate (strm, flush)
|
| 583 | z_streamp strm;
|
| 584 | int flush;
|
| 585 | {
|
| 586 | int old_flush; /* value of flush param for previous deflate call */
|
| 587 | deflate_state *s;
|
| 588 |
|
| 589 | if (strm == Z_NULL || strm->state == Z_NULL ||
|
| 590 | flush > Z_BLOCK || flush < 0) {
|
| 591 | return Z_STREAM_ERROR;
|
| 592 | }
|
| 593 | s = strm->state;
|
| 594 |
|
| 595 | if (strm->next_out == Z_NULL ||
|
| 596 | (strm->next_in == Z_NULL && strm->avail_in != 0) ||
|
| 597 | (s->status == FINISH_STATE && flush != Z_FINISH)) {
|
| 598 | ERR_RETURN(strm, Z_STREAM_ERROR);
|
| 599 | }
|
| 600 | if (strm->avail_out == 0) ERR_RETURN(strm, Z_BUF_ERROR);
|
| 601 |
|
| 602 | s->strm = strm; /* just in case */
|
| 603 | old_flush = s->last_flush;
|
| 604 | s->last_flush = flush;
|
| 605 |
|
| 606 | /* Write the header */
|
| 607 | if (s->status == INIT_STATE) {
|
| 608 | #ifdef GZIP
|
| 609 | if (s->wrap == 2) {
|
| 610 | strm->adler = crc32(0L, Z_NULL, 0);
|
| 611 | put_byte(s, 31);
|
| 612 | put_byte(s, 139);
|
| 613 | put_byte(s, 8);
|
| 614 | if (s->gzhead == Z_NULL) {
|
| 615 | put_byte(s, 0);
|
| 616 | put_byte(s, 0);
|
| 617 | put_byte(s, 0);
|
| 618 | put_byte(s, 0);
|
| 619 | put_byte(s, 0);
|
| 620 | put_byte(s, s->level == 9 ? 2 :
|
| 621 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
|
| 622 | 4 : 0));
|
| 623 | put_byte(s, OS_CODE);
|
| 624 | s->status = BUSY_STATE;
|
| 625 | }
|
| 626 | else {
|
| 627 | put_byte(s, (s->gzhead->text ? 1 : 0) +
|
| 628 | (s->gzhead->hcrc ? 2 : 0) +
|
| 629 | (s->gzhead->extra == Z_NULL ? 0 : 4) +
|
| 630 | (s->gzhead->name == Z_NULL ? 0 : 8) +
|
| 631 | (s->gzhead->comment == Z_NULL ? 0 : 16)
|
| 632 | );
|
| 633 | put_byte(s, (Byte)(s->gzhead->time & 0xff));
|
| 634 | put_byte(s, (Byte)((s->gzhead->time >> 8) & 0xff));
|
| 635 | put_byte(s, (Byte)((s->gzhead->time >> 16) & 0xff));
|
| 636 | put_byte(s, (Byte)((s->gzhead->time >> 24) & 0xff));
|
| 637 | put_byte(s, s->level == 9 ? 2 :
|
| 638 | (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2 ?
|
| 639 | 4 : 0));
|
| 640 | put_byte(s, s->gzhead->os & 0xff);
|
| 641 | if (s->gzhead->extra != Z_NULL) {
|
| 642 | put_byte(s, s->gzhead->extra_len & 0xff);
|
| 643 | put_byte(s, (s->gzhead->extra_len >> 8) & 0xff);
|
| 644 | }
|
| 645 | if (s->gzhead->hcrc)
|
| 646 | strm->adler = crc32(strm->adler, s->pending_buf,
|
| 647 | s->pending);
|
| 648 | s->gzindex = 0;
|
| 649 | s->status = EXTRA_STATE;
|
| 650 | }
|
| 651 | }
|
| 652 | else
|
| 653 | #endif
|
| 654 | {
|
| 655 | uInt header = (Z_DEFLATED + ((s->w_bits-8)<<4)) << 8;
|
| 656 | uInt level_flags;
|
| 657 |
|
| 658 | if (s->strategy >= Z_HUFFMAN_ONLY || s->level < 2)
|
| 659 | level_flags = 0;
|
| 660 | else if (s->level < 6)
|
| 661 | level_flags = 1;
|
| 662 | else if (s->level == 6)
|
| 663 | level_flags = 2;
|
| 664 | else
|
| 665 | level_flags = 3;
|
| 666 | header |= (level_flags << 6);
|
| 667 | if (s->strstart != 0) header |= PRESET_DICT;
|
| 668 | header += 31 - (header % 31);
|
| 669 |
|
| 670 | s->status = BUSY_STATE;
|
| 671 | putShortMSB(s, header);
|
| 672 |
|
| 673 | /* Save the adler32 of the preset dictionary: */
|
| 674 | if (s->strstart != 0) {
|
| 675 | putShortMSB(s, (uInt)(strm->adler >> 16));
|
| 676 | putShortMSB(s, (uInt)(strm->adler & 0xffff));
|
| 677 | }
|
| 678 | strm->adler = adler32(0L, Z_NULL, 0);
|
| 679 | }
|
| 680 | }
|
| 681 | #ifdef GZIP
|
| 682 | if (s->status == EXTRA_STATE) {
|
| 683 | if (s->gzhead->extra != Z_NULL) {
|
| 684 | uInt beg = s->pending; /* start of bytes to update crc */
|
| 685 |
|
| 686 | while (s->gzindex < (s->gzhead->extra_len & 0xffff)) {
|
| 687 | if (s->pending == s->pending_buf_size) {
|
| 688 | if (s->gzhead->hcrc && s->pending > beg)
|
| 689 | strm->adler = crc32(strm->adler, s->pending_buf + beg,
|
| 690 | s->pending - beg);
|
| 691 | flush_pending(strm);
|
| 692 | beg = s->pending;
|
| 693 | if (s->pending == s->pending_buf_size)
|
| 694 | break;
|
| 695 | }
|
| 696 | put_byte(s, s->gzhead->extra[s->gzindex]);
|
| 697 | s->gzindex++;
|
| 698 | }
|
| 699 | if (s->gzhead->hcrc && s->pending > beg)
|
| 700 | strm->adler = crc32(strm->adler, s->pending_buf + beg,
|
| 701 | s->pending - beg);
|
| 702 | if (s->gzindex == s->gzhead->extra_len) {
|
| 703 | s->gzindex = 0;
|
| 704 | s->status = NAME_STATE;
|
| 705 | }
|
| 706 | }
|
| 707 | else
|
| 708 | s->status = NAME_STATE;
|
| 709 | }
|
| 710 | if (s->status == NAME_STATE) {
|
| 711 | if (s->gzhead->name != Z_NULL) {
|
| 712 | uInt beg = s->pending; /* start of bytes to update crc */
|
| 713 | int val;
|
| 714 |
|
| 715 | do {
|
| 716 | if (s->pending == s->pending_buf_size) {
|
| 717 | if (s->gzhead->hcrc && s->pending > beg)
|
| 718 | strm->adler = crc32(strm->adler, s->pending_buf + beg,
|
| 719 | s->pending - beg);
|
| 720 | flush_pending(strm);
|
| 721 | beg = s->pending;
|
| 722 | if (s->pending == s->pending_buf_size) {
|
| 723 | val = 1;
|
| 724 | break;
|
| 725 | }
|
| 726 | }
|
| 727 | val = s->gzhead->name[s->gzindex++];
|
| 728 | put_byte(s, val);
|
| 729 | } while (val != 0);
|
| 730 | if (s->gzhead->hcrc && s->pending > beg)
|
| 731 | strm->adler = crc32(strm->adler, s->pending_buf + beg,
|
| 732 | s->pending - beg);
|
| 733 | if (val == 0) {
|
| 734 | s->gzindex = 0;
|
| 735 | s->status = COMMENT_STATE;
|
| 736 | }
|
| 737 | }
|
| 738 | else
|
| 739 | s->status = COMMENT_STATE;
|
| 740 | }
|
| 741 | if (s->status == COMMENT_STATE) {
|
| 742 | if (s->gzhead->comment != Z_NULL) {
|
| 743 | uInt beg = s->pending; /* start of bytes to update crc */
|
| 744 | int val;
|
| 745 |
|
| 746 | do {
|
| 747 | if (s->pending == s->pending_buf_size) {
|
| 748 | if (s->gzhead->hcrc && s->pending > beg)
|
| 749 | strm->adler = crc32(strm->adler, s->pending_buf + beg,
|
| 750 | s->pending - beg);
|
| 751 | flush_pending(strm);
|
| 752 | beg = s->pending;
|
| 753 | if (s->pending == s->pending_buf_size) {
|
| 754 | val = 1;
|
| 755 | break;
|
| 756 | }
|
| 757 | }
|
| 758 | val = s->gzhead->comment[s->gzindex++];
|
| 759 | put_byte(s, val);
|
| 760 | } while (val != 0);
|
| 761 | if (s->gzhead->hcrc && s->pending > beg)
|
| 762 | strm->adler = crc32(strm->adler, s->pending_buf + beg,
|
| 763 | s->pending - beg);
|
| 764 | if (val == 0)
|
| 765 | s->status = HCRC_STATE;
|
| 766 | }
|
| 767 | else
|
| 768 | s->status = HCRC_STATE;
|
| 769 | }
|
| 770 | if (s->status == HCRC_STATE) {
|
| 771 | if (s->gzhead->hcrc) {
|
| 772 | if (s->pending + 2 > s->pending_buf_size)
|
| 773 | flush_pending(strm);
|
| 774 | if (s->pending + 2 <= s->pending_buf_size) {
|
| 775 | put_byte(s, (Byte)(strm->adler & 0xff));
|
| 776 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
|
| 777 | strm->adler = crc32(0L, Z_NULL, 0);
|
| 778 | s->status = BUSY_STATE;
|
| 779 | }
|
| 780 | }
|
| 781 | else
|
| 782 | s->status = BUSY_STATE;
|
| 783 | }
|
| 784 | #endif
|
| 785 |
|
| 786 | /* Flush as much pending output as possible */
|
| 787 | if (s->pending != 0) {
|
| 788 | flush_pending(strm);
|
| 789 | if (strm->avail_out == 0) {
|
| 790 | /* Since avail_out is 0, deflate will be called again with
|
| 791 | * more output space, but possibly with both pending and
|
| 792 | * avail_in equal to zero. There won't be anything to do,
|
| 793 | * but this is not an error situation so make sure we
|
| 794 | * return OK instead of BUF_ERROR at next call of deflate:
|
| 795 | */
|
| 796 | s->last_flush = -1;
|
| 797 | return Z_OK;
|
| 798 | }
|
| 799 |
|
| 800 | /* Make sure there is something to do and avoid duplicate consecutive
|
| 801 | * flushes. For repeated and useless calls with Z_FINISH, we keep
|
| 802 | * returning Z_STREAM_END instead of Z_BUF_ERROR.
|
| 803 | */
|
| 804 | } else if (strm->avail_in == 0 && flush <= old_flush &&
|
| 805 | flush != Z_FINISH) {
|
| 806 | ERR_RETURN(strm, Z_BUF_ERROR);
|
| 807 | }
|
| 808 |
|
| 809 | /* User must not provide more input after the first FINISH: */
|
| 810 | if (s->status == FINISH_STATE && strm->avail_in != 0) {
|
| 811 | ERR_RETURN(strm, Z_BUF_ERROR);
|
| 812 | }
|
| 813 |
|
| 814 | /* Start a new block or continue the current one.
|
| 815 | */
|
| 816 | if (strm->avail_in != 0 || s->lookahead != 0 ||
|
| 817 | (flush != Z_NO_FLUSH && s->status != FINISH_STATE)) {
|
| 818 | block_state bstate;
|
| 819 |
|
| 820 | bstate = s->strategy == Z_HUFFMAN_ONLY ? deflate_huff(s, flush) :
|
| 821 | (s->strategy == Z_RLE ? deflate_rle(s, flush) :
|
| 822 | (*(configuration_table[s->level].func))(s, flush));
|
| 823 |
|
| 824 | if (bstate == finish_started || bstate == finish_done) {
|
| 825 | s->status = FINISH_STATE;
|
| 826 | }
|
| 827 | if (bstate == need_more || bstate == finish_started) {
|
| 828 | if (strm->avail_out == 0) {
|
| 829 | s->last_flush = -1; /* avoid BUF_ERROR next call, see above */
|
| 830 | }
|
| 831 | return Z_OK;
|
| 832 | /* If flush != Z_NO_FLUSH && avail_out == 0, the next call
|
| 833 | * of deflate should use the same flush parameter to make sure
|
| 834 | * that the flush is complete. So we don't have to output an
|
| 835 | * empty block here, this will be done at next call. This also
|
| 836 | * ensures that for a very small output buffer, we emit at most
|
| 837 | * one empty block.
|
| 838 | */
|
| 839 | }
|
| 840 | if (bstate == block_done) {
|
| 841 | if (flush == Z_PARTIAL_FLUSH) {
|
| 842 | _tr_align(s);
|
| 843 | } else if (flush != Z_BLOCK) { /* FULL_FLUSH or SYNC_FLUSH */
|
| 844 | _tr_stored_block(s, (char*)0, 0L, 0);
|
| 845 | /* For a full flush, this empty block will be recognized
|
| 846 | * as a special marker by inflate_sync().
|
| 847 | */
|
| 848 | if (flush == Z_FULL_FLUSH) {
|
| 849 | CLEAR_HASH(s); /* forget history */
|
| 850 | if (s->lookahead == 0) {
|
| 851 | s->strstart = 0;
|
| 852 | s->block_start = 0L;
|
| 853 | }
|
| 854 | }
|
| 855 | }
|
| 856 | flush_pending(strm);
|
| 857 | if (strm->avail_out == 0) {
|
| 858 | s->last_flush = -1; /* avoid BUF_ERROR at next call, see above */
|
| 859 | return Z_OK;
|
| 860 | }
|
| 861 | }
|
| 862 | }
|
| 863 | Assert(strm->avail_out > 0, "bug2");
|
| 864 |
|
| 865 | if (flush != Z_FINISH) return Z_OK;
|
| 866 | if (s->wrap <= 0) return Z_STREAM_END;
|
| 867 |
|
| 868 | /* Write the trailer */
|
| 869 | #ifdef GZIP
|
| 870 | if (s->wrap == 2) {
|
| 871 | put_byte(s, (Byte)(strm->adler & 0xff));
|
| 872 | put_byte(s, (Byte)((strm->adler >> 8) & 0xff));
|
| 873 | put_byte(s, (Byte)((strm->adler >> 16) & 0xff));
|
| 874 | put_byte(s, (Byte)((strm->adler >> 24) & 0xff));
|
| 875 | put_byte(s, (Byte)(strm->total_in & 0xff));
|
| 876 | put_byte(s, (Byte)((strm->total_in >> 8) & 0xff));
|
| 877 | put_byte(s, (Byte)((strm->total_in >> 16) & 0xff));
|
| 878 | put_byte(s, (Byte)((strm->total_in >> 24) & 0xff));
|
| 879 | }
|
| 880 | else
|
| 881 | #endif
|
| 882 | {
|
| 883 | putShortMSB(s, (uInt)(strm->adler >> 16));
|
| 884 | putShortMSB(s, (uInt)(strm->adler & 0xffff));
|
| 885 | }
|
| 886 | flush_pending(strm);
|
| 887 | /* If avail_out is zero, the application will call deflate again
|
| 888 | * to flush the rest.
|
| 889 | */
|
| 890 | if (s->wrap > 0) s->wrap = -s->wrap; /* write the trailer only once! */
|
| 891 | return s->pending != 0 ? Z_OK : Z_STREAM_END;
|
| 892 | }
|
| 893 |
|
| 894 | /* ========================================================================= */
|
| 895 | int ZEXPORT deflateEnd (strm)
|
| 896 | z_streamp strm;
|
| 897 | {
|
| 898 | int status;
|
| 899 |
|
| 900 | if (strm == Z_NULL || strm->state == Z_NULL) return Z_STREAM_ERROR;
|
| 901 |
|
| 902 | status = strm->state->status;
|
| 903 | if (status != INIT_STATE &&
|
| 904 | status != EXTRA_STATE &&
|
| 905 | status != NAME_STATE &&
|
| 906 | status != COMMENT_STATE &&
|
| 907 | status != HCRC_STATE &&
|
| 908 | status != BUSY_STATE &&
|
| 909 | status != FINISH_STATE) {
|
| 910 | return Z_STREAM_ERROR;
|
| 911 | }
|
| 912 |
|
| 913 | /* Deallocate in reverse order of allocations: */
|
| 914 | TRY_FREE(strm, strm->state->pending_buf);
|
| 915 | TRY_FREE(strm, strm->state->head);
|
| 916 | TRY_FREE(strm, strm->state->prev);
|
| 917 | TRY_FREE(strm, strm->state->window);
|
| 918 |
|
| 919 | ZFREE(strm, strm->state);
|
| 920 | strm->state = Z_NULL;
|
| 921 |
|
| 922 | return status == BUSY_STATE ? Z_DATA_ERROR : Z_OK;
|
| 923 | }
|
| 924 |
|
| 925 | /* =========================================================================
|
| 926 | * Copy the source state to the destination state.
|
| 927 | * To simplify the source, this is not supported for 16-bit MSDOS (which
|
| 928 | * doesn't have enough memory anyway to duplicate compression states).
|
| 929 | */
|
| 930 | int ZEXPORT deflateCopy (dest, source)
|
| 931 | z_streamp dest;
|
| 932 | z_streamp source;
|
| 933 | {
|
| 934 | #ifdef MAXSEG_64K
|
| 935 | return Z_STREAM_ERROR;
|
| 936 | #else
|
| 937 | deflate_state *ds;
|
| 938 | deflate_state *ss;
|
| 939 | ushf *overlay;
|
| 940 |
|
| 941 |
|
| 942 | if (source == Z_NULL || dest == Z_NULL || source->state == Z_NULL) {
|
| 943 | return Z_STREAM_ERROR;
|
| 944 | }
|
| 945 |
|
| 946 | ss = source->state;
|
| 947 |
|
| 948 | zmemcpy(dest, source, sizeof(z_stream));
|
| 949 |
|
| 950 | ds = (deflate_state *) ZALLOC(dest, 1, sizeof(deflate_state));
|
| 951 | if (ds == Z_NULL) return Z_MEM_ERROR;
|
| 952 | dest->state = (struct internal_state FAR *) ds;
|
| 953 | zmemcpy(ds, ss, sizeof(deflate_state));
|
| 954 | ds->strm = dest;
|
| 955 |
|
| 956 | ds->window = (Bytef *) ZALLOC(dest, ds->w_size, 2*sizeof(Byte));
|
| 957 | ds->prev = (Posf *) ZALLOC(dest, ds->w_size, sizeof(Pos));
|
| 958 | ds->head = (Posf *) ZALLOC(dest, ds->hash_size, sizeof(Pos));
|
| 959 | overlay = (ushf *) ZALLOC(dest, ds->lit_bufsize, sizeof(ush)+2);
|
| 960 | ds->pending_buf = (uchf *) overlay;
|
| 961 |
|
| 962 | if (ds->window == Z_NULL || ds->prev == Z_NULL || ds->head == Z_NULL ||
|
| 963 | ds->pending_buf == Z_NULL) {
|
| 964 | deflateEnd (dest);
|
| 965 | return Z_MEM_ERROR;
|
| 966 | }
|
| 967 | /* following zmemcpy do not work for 16-bit MSDOS */
|
| 968 | zmemcpy(ds->window, ss->window, ds->w_size * 2 * sizeof(Byte));
|
| 969 | zmemcpy(ds->prev, ss->prev, ds->w_size * sizeof(Pos));
|
| 970 | zmemcpy(ds->head, ss->head, ds->hash_size * sizeof(Pos));
|
| 971 | zmemcpy(ds->pending_buf, ss->pending_buf, (uInt)ds->pending_buf_size);
|
| 972 |
|
| 973 | ds->pending_out = ds->pending_buf + (ss->pending_out - ss->pending_buf);
|
| 974 | ds->d_buf = overlay + ds->lit_bufsize/sizeof(ush);
|
| 975 | ds->l_buf = ds->pending_buf + (1+sizeof(ush))*ds->lit_bufsize;
|
| 976 |
|
| 977 | ds->l_desc.dyn_tree = ds->dyn_ltree;
|
| 978 | ds->d_desc.dyn_tree = ds->dyn_dtree;
|
| 979 | ds->bl_desc.dyn_tree = ds->bl_tree;
|
| 980 |
|
| 981 | return Z_OK;
|
| 982 | #endif /* MAXSEG_64K */
|
| 983 | }
|
| 984 |
|
| 985 | /* ===========================================================================
|
| 986 | * Read a new buffer from the current input stream, update the adler32
|
| 987 | * and total number of bytes read. All deflate() input goes through
|
| 988 | * this function so some applications may wish to modify it to avoid
|
| 989 | * allocating a large strm->next_in buffer and copying from it.
|
| 990 | * (See also flush_pending()).
|
| 991 | */
|
| 992 | local int read_buf(strm, buf, size)
|
| 993 | z_streamp strm;
|
| 994 | Bytef *buf;
|
| 995 | unsigned size;
|
| 996 | {
|
| 997 | unsigned len = strm->avail_in;
|
| 998 |
|
| 999 | if (len > size) len = size;
|
| 1000 | if (len == 0) return 0;
|
| 1001 |
|
| 1002 | strm->avail_in -= len;
|
| 1003 |
|
| 1004 | if (strm->state->wrap == 1) {
|
| 1005 | strm->adler = adler32(strm->adler, strm->next_in, len);
|
| 1006 | }
|
| 1007 | #ifdef GZIP
|
| 1008 | else if (strm->state->wrap == 2) {
|
| 1009 | strm->adler = crc32(strm->adler, strm->next_in, len);
|
| 1010 | }
|
| 1011 | #endif
|
| 1012 | zmemcpy(buf, strm->next_in, len);
|
| 1013 | strm->next_in += len;
|
| 1014 | strm->total_in += len;
|
| 1015 |
|
| 1016 | return (int)len;
|
| 1017 | }
|
| 1018 |
|
| 1019 | /* ===========================================================================
|
| 1020 | * Initialize the "longest match" routines for a new zlib stream
|
| 1021 | */
|
| 1022 | local void lm_init (s)
|
| 1023 | deflate_state *s;
|
| 1024 | {
|
| 1025 | s->window_size = (ulg)2L*s->w_size;
|
| 1026 |
|
| 1027 | CLEAR_HASH(s);
|
| 1028 |
|
| 1029 | /* Set the default configuration parameters:
|
| 1030 | */
|
| 1031 | s->max_lazy_match = configuration_table[s->level].max_lazy;
|
| 1032 | s->good_match = configuration_table[s->level].good_length;
|
| 1033 | s->nice_match = configuration_table[s->level].nice_length;
|
| 1034 | s->max_chain_length = configuration_table[s->level].max_chain;
|
| 1035 |
|
| 1036 | s->strstart = 0;
|
| 1037 | s->block_start = 0L;
|
| 1038 | s->lookahead = 0;
|
| 1039 | s->match_length = s->prev_length = MIN_MATCH-1;
|
| 1040 | s->match_available = 0;
|
| 1041 | s->ins_h = 0;
|
| 1042 | #ifndef FASTEST
|
| 1043 | #ifdef ASMV
|
| 1044 | match_init(); /* initialize the asm code */
|
| 1045 | #endif
|
| 1046 | #endif
|
| 1047 | }
|
| 1048 |
|
| 1049 | #ifndef FASTEST
|
| 1050 | /* ===========================================================================
|
| 1051 | * Set match_start to the longest match starting at the given string and
|
| 1052 | * return its length. Matches shorter or equal to prev_length are discarded,
|
| 1053 | * in which case the result is equal to prev_length and match_start is
|
| 1054 | * garbage.
|
| 1055 | * IN assertions: cur_match is the head of the hash chain for the current
|
| 1056 | * string (strstart) and its distance is <= MAX_DIST, and prev_length >= 1
|
| 1057 | * OUT assertion: the match length is not greater than s->lookahead.
|
| 1058 | */
|
| 1059 | #ifndef ASMV
|
| 1060 | /* For 80x86 and 680x0, an optimized version will be provided in match.asm or
|
| 1061 | * match.S. The code will be functionally equivalent.
|
| 1062 | */
|
| 1063 | local uInt longest_match(s, cur_match)
|
| 1064 | deflate_state *s;
|
| 1065 | IPos cur_match; /* current match */
|
| 1066 | {
|
| 1067 | unsigned chain_length = s->max_chain_length;/* max hash chain length */
|
| 1068 | register Bytef *scan = s->window + s->strstart; /* current string */
|
| 1069 | register Bytef *match; /* matched string */
|
| 1070 | register int len; /* length of current match */
|
| 1071 | int best_len = s->prev_length; /* best match length so far */
|
| 1072 | int nice_match = s->nice_match; /* stop if match long enough */
|
| 1073 | IPos limit = s->strstart > (IPos)MAX_DIST(s) ?
|
| 1074 | s->strstart - (IPos)MAX_DIST(s) : NIL;
|
| 1075 | /* Stop when cur_match becomes <= limit. To simplify the code,
|
| 1076 | * we prevent matches with the string of window index 0.
|
| 1077 | */
|
| 1078 | Posf *prev = s->prev;
|
| 1079 | uInt wmask = s->w_mask;
|
| 1080 |
|
| 1081 | #ifdef UNALIGNED_OK
|
| 1082 | /* Compare two bytes at a time. Note: this is not always beneficial.
|
| 1083 | * Try with and without -DUNALIGNED_OK to check.
|
| 1084 | */
|
| 1085 | register Bytef *strend = s->window + s->strstart + MAX_MATCH - 1;
|
| 1086 | register ush scan_start = *(ushf*)scan;
|
| 1087 | register ush scan_end = *(ushf*)(scan+best_len-1);
|
| 1088 | #else
|
| 1089 | register Bytef *strend = s->window + s->strstart + MAX_MATCH;
|
| 1090 | register Byte scan_end1 = scan[best_len-1];
|
| 1091 | register Byte scan_end = scan[best_len];
|
| 1092 | #endif
|
| 1093 |
|
| 1094 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
|
| 1095 | * It is easy to get rid of this optimization if necessary.
|
| 1096 | */
|
| 1097 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
|
| 1098 |
|
| 1099 | /* Do not waste too much time if we already have a good match: */
|
| 1100 | if (s->prev_length >= s->good_match) {
|
| 1101 | chain_length >>= 2;
|
| 1102 | }
|
| 1103 | /* Do not look for matches beyond the end of the input. This is necessary
|
| 1104 | * to make deflate deterministic.
|
| 1105 | */
|
| 1106 | if ((uInt)nice_match > s->lookahead) nice_match = s->lookahead;
|
| 1107 |
|
| 1108 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
|
| 1109 |
|
| 1110 | do {
|
| 1111 | Assert(cur_match < s->strstart, "no future");
|
| 1112 | match = s->window + cur_match;
|
| 1113 |
|
| 1114 | /* Skip to next match if the match length cannot increase
|
| 1115 | * or if the match length is less than 2. Note that the checks below
|
| 1116 | * for insufficient lookahead only occur occasionally for performance
|
| 1117 | * reasons. Therefore uninitialized memory will be accessed, and
|
| 1118 | * conditional jumps will be made that depend on those values.
|
| 1119 | * However the length of the match is limited to the lookahead, so
|
| 1120 | * the output of deflate is not affected by the uninitialized values.
|
| 1121 | */
|
| 1122 | #if (defined(UNALIGNED_OK) && MAX_MATCH == 258)
|
| 1123 | /* This code assumes sizeof(unsigned short) == 2. Do not use
|
| 1124 | * UNALIGNED_OK if your compiler uses a different size.
|
| 1125 | */
|
| 1126 | if (*(ushf*)(match+best_len-1) != scan_end ||
|
| 1127 | *(ushf*)match != scan_start) continue;
|
| 1128 |
|
| 1129 | /* It is not necessary to compare scan[2] and match[2] since they are
|
| 1130 | * always equal when the other bytes match, given that the hash keys
|
| 1131 | * are equal and that HASH_BITS >= 8. Compare 2 bytes at a time at
|
| 1132 | * strstart+3, +5, ... up to strstart+257. We check for insufficient
|
| 1133 | * lookahead only every 4th comparison; the 128th check will be made
|
| 1134 | * at strstart+257. If MAX_MATCH-2 is not a multiple of 8, it is
|
| 1135 | * necessary to put more guard bytes at the end of the window, or
|
| 1136 | * to check more often for insufficient lookahead.
|
| 1137 | */
|
| 1138 | Assert(scan[2] == match[2], "scan[2]?");
|
| 1139 | scan++, match++;
|
| 1140 | do {
|
| 1141 | } while (*(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
|
| 1142 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
|
| 1143 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
|
| 1144 | *(ushf*)(scan+=2) == *(ushf*)(match+=2) &&
|
| 1145 | scan < strend);
|
| 1146 | /* The funny "do {}" generates better code on most compilers */
|
| 1147 |
|
| 1148 | /* Here, scan <= window+strstart+257 */
|
| 1149 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
|
| 1150 | if (*scan == *match) scan++;
|
| 1151 |
|
| 1152 | len = (MAX_MATCH - 1) - (int)(strend-scan);
|
| 1153 | scan = strend - (MAX_MATCH-1);
|
| 1154 |
|
| 1155 | #else /* UNALIGNED_OK */
|
| 1156 |
|
| 1157 | if (match[best_len] != scan_end ||
|
| 1158 | match[best_len-1] != scan_end1 ||
|
| 1159 | *match != *scan ||
|
| 1160 | *++match != scan[1]) continue;
|
| 1161 |
|
| 1162 | /* The check at best_len-1 can be removed because it will be made
|
| 1163 | * again later. (This heuristic is not always a win.)
|
| 1164 | * It is not necessary to compare scan[2] and match[2] since they
|
| 1165 | * are always equal when the other bytes match, given that
|
| 1166 | * the hash keys are equal and that HASH_BITS >= 8.
|
| 1167 | */
|
| 1168 | scan += 2, match++;
|
| 1169 | Assert(*scan == *match, "match[2]?");
|
| 1170 |
|
| 1171 | /* We check for insufficient lookahead only every 8th comparison;
|
| 1172 | * the 256th check will be made at strstart+258.
|
| 1173 | */
|
| 1174 | do {
|
| 1175 | } while (*++scan == *++match && *++scan == *++match &&
|
| 1176 | *++scan == *++match && *++scan == *++match &&
|
| 1177 | *++scan == *++match && *++scan == *++match &&
|
| 1178 | *++scan == *++match && *++scan == *++match &&
|
| 1179 | scan < strend);
|
| 1180 |
|
| 1181 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
|
| 1182 |
|
| 1183 | len = MAX_MATCH - (int)(strend - scan);
|
| 1184 | scan = strend - MAX_MATCH;
|
| 1185 |
|
| 1186 | #endif /* UNALIGNED_OK */
|
| 1187 |
|
| 1188 | if (len > best_len) {
|
| 1189 | s->match_start = cur_match;
|
| 1190 | best_len = len;
|
| 1191 | if (len >= nice_match) break;
|
| 1192 | #ifdef UNALIGNED_OK
|
| 1193 | scan_end = *(ushf*)(scan+best_len-1);
|
| 1194 | #else
|
| 1195 | scan_end1 = scan[best_len-1];
|
| 1196 | scan_end = scan[best_len];
|
| 1197 | #endif
|
| 1198 | }
|
| 1199 | } while ((cur_match = prev[cur_match & wmask]) > limit
|
| 1200 | && --chain_length != 0);
|
| 1201 |
|
| 1202 | if ((uInt)best_len <= s->lookahead) return (uInt)best_len;
|
| 1203 | return s->lookahead;
|
| 1204 | }
|
| 1205 | #endif /* ASMV */
|
| 1206 |
|
| 1207 | #else /* FASTEST */
|
| 1208 |
|
| 1209 | /* ---------------------------------------------------------------------------
|
| 1210 | * Optimized version for FASTEST only
|
| 1211 | */
|
| 1212 | local uInt longest_match(s, cur_match)
|
| 1213 | deflate_state *s;
|
| 1214 | IPos cur_match; /* current match */
|
| 1215 | {
|
| 1216 | register Bytef *scan = s->window + s->strstart; /* current string */
|
| 1217 | register Bytef *match; /* matched string */
|
| 1218 | register int len; /* length of current match */
|
| 1219 | register Bytef *strend = s->window + s->strstart + MAX_MATCH;
|
| 1220 |
|
| 1221 | /* The code is optimized for HASH_BITS >= 8 and MAX_MATCH-2 multiple of 16.
|
| 1222 | * It is easy to get rid of this optimization if necessary.
|
| 1223 | */
|
| 1224 | Assert(s->hash_bits >= 8 && MAX_MATCH == 258, "Code too clever");
|
| 1225 |
|
| 1226 | Assert((ulg)s->strstart <= s->window_size-MIN_LOOKAHEAD, "need lookahead");
|
| 1227 |
|
| 1228 | Assert(cur_match < s->strstart, "no future");
|
| 1229 |
|
| 1230 | match = s->window + cur_match;
|
| 1231 |
|
| 1232 | /* Return failure if the match length is less than 2:
|
| 1233 | */
|
| 1234 | if (match[0] != scan[0] || match[1] != scan[1]) return MIN_MATCH-1;
|
| 1235 |
|
| 1236 | /* The check at best_len-1 can be removed because it will be made
|
| 1237 | * again later. (This heuristic is not always a win.)
|
| 1238 | * It is not necessary to compare scan[2] and match[2] since they
|
| 1239 | * are always equal when the other bytes match, given that
|
| 1240 | * the hash keys are equal and that HASH_BITS >= 8.
|
| 1241 | */
|
| 1242 | scan += 2, match += 2;
|
| 1243 | Assert(*scan == *match, "match[2]?");
|
| 1244 |
|
| 1245 | /* We check for insufficient lookahead only every 8th comparison;
|
| 1246 | * the 256th check will be made at strstart+258.
|
| 1247 | */
|
| 1248 | do {
|
| 1249 | } while (*++scan == *++match && *++scan == *++match &&
|
| 1250 | *++scan == *++match && *++scan == *++match &&
|
| 1251 | *++scan == *++match && *++scan == *++match &&
|
| 1252 | *++scan == *++match && *++scan == *++match &&
|
| 1253 | scan < strend);
|
| 1254 |
|
| 1255 | Assert(scan <= s->window+(unsigned)(s->window_size-1), "wild scan");
|
| 1256 |
|
| 1257 | len = MAX_MATCH - (int)(strend - scan);
|
| 1258 |
|
| 1259 | if (len < MIN_MATCH) return MIN_MATCH - 1;
|
| 1260 |
|
| 1261 | s->match_start = cur_match;
|
| 1262 | return (uInt)len <= s->lookahead ? (uInt)len : s->lookahead;
|
| 1263 | }
|
| 1264 |
|
| 1265 | #endif /* FASTEST */
|
| 1266 |
|
| 1267 | #ifdef DEBUG
|
| 1268 | /* ===========================================================================
|
| 1269 | * Check that the match at match_start is indeed a match.
|
| 1270 | */
|
| 1271 | local void check_match(s, start, match, length)
|
| 1272 | deflate_state *s;
|
| 1273 | IPos start, match;
|
| 1274 | int length;
|
| 1275 | {
|
| 1276 | /* check that the match is indeed a match */
|
| 1277 | if (zmemcmp(s->window + match,
|
| 1278 | s->window + start, length) != EQUAL) {
|
| 1279 | fprintf(stderr, " start %u, match %u, length %d\n",
|
| 1280 | start, match, length);
|
| 1281 | do {
|
| 1282 | fprintf(stderr, "%c%c", s->window[match++], s->window[start++]);
|
| 1283 | } while (--length != 0);
|
| 1284 | z_error("invalid match");
|
| 1285 | }
|
| 1286 | if (z_verbose > 1) {
|
| 1287 | fprintf(stderr,"\\[%d,%d]", start-match, length);
|
| 1288 | do { putc(s->window[start++], stderr); } while (--length != 0);
|
| 1289 | }
|
| 1290 | }
|
| 1291 | #else
|
| 1292 | # define check_match(s, start, match, length)
|
| 1293 | #endif /* DEBUG */
|
| 1294 |
|
| 1295 | /* ===========================================================================
|
| 1296 | * Fill the window when the lookahead becomes insufficient.
|
| 1297 | * Updates strstart and lookahead.
|
| 1298 | *
|
| 1299 | * IN assertion: lookahead < MIN_LOOKAHEAD
|
| 1300 | * OUT assertions: strstart <= window_size-MIN_LOOKAHEAD
|
| 1301 | * At least one byte has been read, or avail_in == 0; reads are
|
| 1302 | * performed for at least two bytes (required for the zip translate_eol
|
| 1303 | * option -- not supported here).
|
| 1304 | */
|
| 1305 | local void fill_window(s)
|
| 1306 | deflate_state *s;
|
| 1307 | {
|
| 1308 | register unsigned n, m;
|
| 1309 | register Posf *p;
|
| 1310 | unsigned more; /* Amount of free space at the end of the window. */
|
| 1311 | uInt wsize = s->w_size;
|
| 1312 |
|
| 1313 | do {
|
| 1314 | more = (unsigned)(s->window_size -(ulg)s->lookahead -(ulg)s->strstart);
|
| 1315 |
|
| 1316 | /* Deal with !@#$% 64K limit: */
|
| 1317 | if (sizeof(int) <= 2) {
|
| 1318 | if (more == 0 && s->strstart == 0 && s->lookahead == 0) {
|
| 1319 | more = wsize;
|
| 1320 |
|
| 1321 | } else if (more == (unsigned)(-1)) {
|
| 1322 | /* Very unlikely, but possible on 16 bit machine if
|
| 1323 | * strstart == 0 && lookahead == 1 (input done a byte at time)
|
| 1324 | */
|
| 1325 | more--;
|
| 1326 | }
|
| 1327 | }
|
| 1328 |
|
| 1329 | /* If the window is almost full and there is insufficient lookahead,
|
| 1330 | * move the upper half to the lower one to make room in the upper half.
|
| 1331 | */
|
| 1332 | if (s->strstart >= wsize+MAX_DIST(s)) {
|
| 1333 |
|
| 1334 | zmemcpy(s->window, s->window+wsize, (unsigned)wsize);
|
| 1335 | s->match_start -= wsize;
|
| 1336 | s->strstart -= wsize; /* we now have strstart >= MAX_DIST */
|
| 1337 | s->block_start -= (long) wsize;
|
| 1338 |
|
| 1339 | /* Slide the hash table (could be avoided with 32 bit values
|
| 1340 | at the expense of memory usage). We slide even when level == 0
|
| 1341 | to keep the hash table consistent if we switch back to level > 0
|
| 1342 | later. (Using level 0 permanently is not an optimal usage of
|
| 1343 | zlib, so we don't care about this pathological case.)
|
| 1344 | */
|
| 1345 | n = s->hash_size;
|
| 1346 | p = &s->head[n];
|
| 1347 | do {
|
| 1348 | m = *--p;
|
| 1349 | *p = (Pos)(m >= wsize ? m-wsize : NIL);
|
| 1350 | } while (--n);
|
| 1351 |
|
| 1352 | n = wsize;
|
| 1353 | #ifndef FASTEST
|
| 1354 | p = &s->prev[n];
|
| 1355 | do {
|
| 1356 | m = *--p;
|
| 1357 | *p = (Pos)(m >= wsize ? m-wsize : NIL);
|
| 1358 | /* If n is not on any hash chain, prev[n] is garbage but
|
| 1359 | * its value will never be used.
|
| 1360 | */
|
| 1361 | } while (--n);
|
| 1362 | #endif
|
| 1363 | more += wsize;
|
| 1364 | }
|
| 1365 | if (s->strm->avail_in == 0) return;
|
| 1366 |
|
| 1367 | /* If there was no sliding:
|
| 1368 | * strstart <= WSIZE+MAX_DIST-1 && lookahead <= MIN_LOOKAHEAD - 1 &&
|
| 1369 | * more == window_size - lookahead - strstart
|
| 1370 | * => more >= window_size - (MIN_LOOKAHEAD-1 + WSIZE + MAX_DIST-1)
|
| 1371 | * => more >= window_size - 2*WSIZE + 2
|
| 1372 | * In the BIG_MEM or MMAP case (not yet supported),
|
| 1373 | * window_size == input_size + MIN_LOOKAHEAD &&
|
| 1374 | * strstart + s->lookahead <= input_size => more >= MIN_LOOKAHEAD.
|
| 1375 | * Otherwise, window_size == 2*WSIZE so more >= 2.
|
| 1376 | * If there was sliding, more >= WSIZE. So in all cases, more >= 2.
|
| 1377 | */
|
| 1378 | Assert(more >= 2, "more < 2");
|
| 1379 |
|
| 1380 | n = read_buf(s->strm, s->window + s->strstart + s->lookahead, more);
|
| 1381 | s->lookahead += n;
|
| 1382 |
|
| 1383 | /* Initialize the hash value now that we have some input: */
|
| 1384 | if (s->lookahead >= MIN_MATCH) {
|
| 1385 | s->ins_h = s->window[s->strstart];
|
| 1386 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
|
| 1387 | #if MIN_MATCH != 3
|
| 1388 | Call UPDATE_HASH() MIN_MATCH-3 more times
|
| 1389 | #endif
|
| 1390 | }
|
| 1391 | /* If the whole input has less than MIN_MATCH bytes, ins_h is garbage,
|
| 1392 | * but this is not important since only literal bytes will be emitted.
|
| 1393 | */
|
| 1394 |
|
| 1395 | } while (s->lookahead < MIN_LOOKAHEAD && s->strm->avail_in != 0);
|
| 1396 |
|
| 1397 | /* If the WIN_INIT bytes after the end of the current data have never been
|
| 1398 | * written, then zero those bytes in order to avoid memory check reports of
|
| 1399 | * the use of uninitialized (or uninitialised as Julian writes) bytes by
|
| 1400 | * the longest match routines. Update the high water mark for the next
|
| 1401 | * time through here. WIN_INIT is set to MAX_MATCH since the longest match
|
| 1402 | * routines allow scanning to strstart + MAX_MATCH, ignoring lookahead.
|
| 1403 | */
|
| 1404 | if (s->high_water < s->window_size) {
|
| 1405 | ulg curr = s->strstart + (ulg)(s->lookahead);
|
| 1406 | ulg init;
|
| 1407 |
|
| 1408 | if (s->high_water < curr) {
|
| 1409 | /* Previous high water mark below current data -- zero WIN_INIT
|
| 1410 | * bytes or up to end of window, whichever is less.
|
| 1411 | */
|
| 1412 | init = s->window_size - curr;
|
| 1413 | if (init > WIN_INIT)
|
| 1414 | init = WIN_INIT;
|
| 1415 | zmemzero(s->window + curr, (unsigned)init);
|
| 1416 | s->high_water = curr + init;
|
| 1417 | }
|
| 1418 | else if (s->high_water < (ulg)curr + WIN_INIT) {
|
| 1419 | /* High water mark at or above current data, but below current data
|
| 1420 | * plus WIN_INIT -- zero out to current data plus WIN_INIT, or up
|
| 1421 | * to end of window, whichever is less.
|
| 1422 | */
|
| 1423 | init = (ulg)curr + WIN_INIT - s->high_water;
|
| 1424 | if (init > s->window_size - s->high_water)
|
| 1425 | init = s->window_size - s->high_water;
|
| 1426 | zmemzero(s->window + s->high_water, (unsigned)init);
|
| 1427 | s->high_water += init;
|
| 1428 | }
|
| 1429 | }
|
| 1430 | }
|
| 1431 |
|
| 1432 | /* ===========================================================================
|
| 1433 | * Flush the current block, with given end-of-file flag.
|
| 1434 | * IN assertion: strstart is set to the end of the current match.
|
| 1435 | */
|
| 1436 | #define FLUSH_BLOCK_ONLY(s, last) { \
|
| 1437 | _tr_flush_block(s, (s->block_start >= 0L ? \
|
| 1438 | (charf *)&s->window[(unsigned)s->block_start] : \
|
| 1439 | (charf *)Z_NULL), \
|
| 1440 | (ulg)((long)s->strstart - s->block_start), \
|
| 1441 | (last)); \
|
| 1442 | s->block_start = s->strstart; \
|
| 1443 | flush_pending(s->strm); \
|
| 1444 | Tracev((stderr,"[FLUSH]")); \
|
| 1445 | }
|
| 1446 |
|
| 1447 | /* Same but force premature exit if necessary. */
|
| 1448 | #define FLUSH_BLOCK(s, last) { \
|
| 1449 | FLUSH_BLOCK_ONLY(s, last); \
|
| 1450 | if (s->strm->avail_out == 0) return (last) ? finish_started : need_more; \
|
| 1451 | }
|
| 1452 |
|
| 1453 | /* ===========================================================================
|
| 1454 | * Copy without compression as much as possible from the input stream, return
|
| 1455 | * the current block state.
|
| 1456 | * This function does not insert new strings in the dictionary since
|
| 1457 | * uncompressible data is probably not useful. This function is used
|
| 1458 | * only for the level=0 compression option.
|
| 1459 | * NOTE: this function should be optimized to avoid extra copying from
|
| 1460 | * window to pending_buf.
|
| 1461 | */
|
| 1462 | local block_state deflate_stored(s, flush)
|
| 1463 | deflate_state *s;
|
| 1464 | int flush;
|
| 1465 | {
|
| 1466 | /* Stored blocks are limited to 0xffff bytes, pending_buf is limited
|
| 1467 | * to pending_buf_size, and each stored block has a 5 byte header:
|
| 1468 | */
|
| 1469 | ulg max_block_size = 0xffff;
|
| 1470 | ulg max_start;
|
| 1471 |
|
| 1472 | if (max_block_size > s->pending_buf_size - 5) {
|
| 1473 | max_block_size = s->pending_buf_size - 5;
|
| 1474 | }
|
| 1475 |
|
| 1476 | /* Copy as much as possible from input to output: */
|
| 1477 | for (;;) {
|
| 1478 | /* Fill the window as much as possible: */
|
| 1479 | if (s->lookahead <= 1) {
|
| 1480 |
|
| 1481 | Assert(s->strstart < s->w_size+MAX_DIST(s) ||
|
| 1482 | s->block_start >= (long)s->w_size, "slide too late");
|
| 1483 |
|
| 1484 | fill_window(s);
|
| 1485 | if (s->lookahead == 0 && flush == Z_NO_FLUSH) return need_more;
|
| 1486 |
|
| 1487 | if (s->lookahead == 0) break; /* flush the current block */
|
| 1488 | }
|
| 1489 | Assert(s->block_start >= 0L, "block gone");
|
| 1490 |
|
| 1491 | s->strstart += s->lookahead;
|
| 1492 | s->lookahead = 0;
|
| 1493 |
|
| 1494 | /* Emit a stored block if pending_buf will be full: */
|
| 1495 | max_start = s->block_start + max_block_size;
|
| 1496 | if (s->strstart == 0 || (ulg)s->strstart >= max_start) {
|
| 1497 | /* strstart == 0 is possible when wraparound on 16-bit machine */
|
| 1498 | s->lookahead = (uInt)(s->strstart - max_start);
|
| 1499 | s->strstart = (uInt)max_start;
|
| 1500 | FLUSH_BLOCK(s, 0);
|
| 1501 | }
|
| 1502 | /* Flush if we may have to slide, otherwise block_start may become
|
| 1503 | * negative and the data will be gone:
|
| 1504 | */
|
| 1505 | if (s->strstart - (uInt)s->block_start >= MAX_DIST(s)) {
|
| 1506 | FLUSH_BLOCK(s, 0);
|
| 1507 | }
|
| 1508 | }
|
| 1509 | FLUSH_BLOCK(s, flush == Z_FINISH);
|
| 1510 | return flush == Z_FINISH ? finish_done : block_done;
|
| 1511 | }
|
| 1512 |
|
| 1513 | /* ===========================================================================
|
| 1514 | * Compress as much as possible from the input stream, return the current
|
| 1515 | * block state.
|
| 1516 | * This function does not perform lazy evaluation of matches and inserts
|
| 1517 | * new strings in the dictionary only for unmatched strings or for short
|
| 1518 | * matches. It is used only for the fast compression options.
|
| 1519 | */
|
| 1520 | local block_state deflate_fast(s, flush)
|
| 1521 | deflate_state *s;
|
| 1522 | int flush;
|
| 1523 | {
|
| 1524 | IPos hash_head; /* head of the hash chain */
|
| 1525 | int bflush; /* set if current block must be flushed */
|
| 1526 |
|
| 1527 | for (;;) {
|
| 1528 | /* Make sure that we always have enough lookahead, except
|
| 1529 | * at the end of the input file. We need MAX_MATCH bytes
|
| 1530 | * for the next match, plus MIN_MATCH bytes to insert the
|
| 1531 | * string following the next match.
|
| 1532 | */
|
| 1533 | if (s->lookahead < MIN_LOOKAHEAD) {
|
| 1534 | fill_window(s);
|
| 1535 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
|
| 1536 | return need_more;
|
| 1537 | }
|
| 1538 | if (s->lookahead == 0) break; /* flush the current block */
|
| 1539 | }
|
| 1540 |
|
| 1541 | /* Insert the string window[strstart .. strstart+2] in the
|
| 1542 | * dictionary, and set hash_head to the head of the hash chain:
|
| 1543 | */
|
| 1544 | hash_head = NIL;
|
| 1545 | if (s->lookahead >= MIN_MATCH) {
|
| 1546 | INSERT_STRING(s, s->strstart, hash_head);
|
| 1547 | }
|
| 1548 |
|
| 1549 | /* Find the longest match, discarding those <= prev_length.
|
| 1550 | * At this point we have always match_length < MIN_MATCH
|
| 1551 | */
|
| 1552 | if (hash_head != NIL && s->strstart - hash_head <= MAX_DIST(s)) {
|
| 1553 | /* To simplify the code, we prevent matches with the string
|
| 1554 | * of window index 0 (in particular we have to avoid a match
|
| 1555 | * of the string with itself at the start of the input file).
|
| 1556 | */
|
| 1557 | s->match_length = longest_match (s, hash_head);
|
| 1558 | /* longest_match() sets match_start */
|
| 1559 | }
|
| 1560 | if (s->match_length >= MIN_MATCH) {
|
| 1561 | check_match(s, s->strstart, s->match_start, s->match_length);
|
| 1562 |
|
| 1563 | _tr_tally_dist(s, s->strstart - s->match_start,
|
| 1564 | s->match_length - MIN_MATCH, bflush);
|
| 1565 |
|
| 1566 | s->lookahead -= s->match_length;
|
| 1567 |
|
| 1568 | /* Insert new strings in the hash table only if the match length
|
| 1569 | * is not too large. This saves time but degrades compression.
|
| 1570 | */
|
| 1571 | #ifndef FASTEST
|
| 1572 | if (s->match_length <= s->max_insert_length &&
|
| 1573 | s->lookahead >= MIN_MATCH) {
|
| 1574 | s->match_length--; /* string at strstart already in table */
|
| 1575 | do {
|
| 1576 | s->strstart++;
|
| 1577 | INSERT_STRING(s, s->strstart, hash_head);
|
| 1578 | /* strstart never exceeds WSIZE-MAX_MATCH, so there are
|
| 1579 | * always MIN_MATCH bytes ahead.
|
| 1580 | */
|
| 1581 | } while (--s->match_length != 0);
|
| 1582 | s->strstart++;
|
| 1583 | } else
|
| 1584 | #endif
|
| 1585 | {
|
| 1586 | s->strstart += s->match_length;
|
| 1587 | s->match_length = 0;
|
| 1588 | s->ins_h = s->window[s->strstart];
|
| 1589 | UPDATE_HASH(s, s->ins_h, s->window[s->strstart+1]);
|
| 1590 | #if MIN_MATCH != 3
|
| 1591 | Call UPDATE_HASH() MIN_MATCH-3 more times
|
| 1592 | #endif
|
| 1593 | /* If lookahead < MIN_MATCH, ins_h is garbage, but it does not
|
| 1594 | * matter since it will be recomputed at next deflate call.
|
| 1595 | */
|
| 1596 | }
|
| 1597 | } else {
|
| 1598 | /* No match, output a literal byte */
|
| 1599 | Tracevv((stderr,"%c", s->window[s->strstart]));
|
| 1600 | _tr_tally_lit (s, s->window[s->strstart], bflush);
|
| 1601 | s->lookahead--;
|
| 1602 | s->strstart++;
|
| 1603 | }
|
| 1604 | if (bflush) FLUSH_BLOCK(s, 0);
|
| 1605 | }
|
| 1606 | FLUSH_BLOCK(s, flush == Z_FINISH);
|
| 1607 | return flush == Z_FINISH ? finish_done : block_done;
|
| 1608 | }
|
| 1609 |
|
| 1610 | #ifndef FASTEST
|
| 1611 | /* ===========================================================================
|
| 1612 | * Same as above, but achieves better compression. We use a lazy
|
| 1613 | * evaluation for matches: a match is finally adopted only if there is
|
| 1614 | * no better match at the next window position.
|
| 1615 | */
|
| 1616 | local block_state deflate_slow(s, flush)
|
| 1617 | deflate_state *s;
|
| 1618 | int flush;
|
| 1619 | {
|
| 1620 | IPos hash_head; /* head of hash chain */
|
| 1621 | int bflush; /* set if current block must be flushed */
|
| 1622 |
|
| 1623 | /* Process the input block. */
|
| 1624 | for (;;) {
|
| 1625 | /* Make sure that we always have enough lookahead, except
|
| 1626 | * at the end of the input file. We need MAX_MATCH bytes
|
| 1627 | * for the next match, plus MIN_MATCH bytes to insert the
|
| 1628 | * string following the next match.
|
| 1629 | */
|
| 1630 | if (s->lookahead < MIN_LOOKAHEAD) {
|
| 1631 | fill_window(s);
|
| 1632 | if (s->lookahead < MIN_LOOKAHEAD && flush == Z_NO_FLUSH) {
|
| 1633 | return need_more;
|
| 1634 | }
|
| 1635 | if (s->lookahead == 0) break; /* flush the current block */
|
| 1636 | }
|
| 1637 |
|
| 1638 | /* Insert the string window[strstart .. strstart+2] in the
|
| 1639 | * dictionary, and set hash_head to the head of the hash chain:
|
| 1640 | */
|
| 1641 | hash_head = NIL;
|
| 1642 | if (s->lookahead >= MIN_MATCH) {
|
| 1643 | INSERT_STRING(s, s->strstart, hash_head);
|
| 1644 | }
|
| 1645 |
|
| 1646 | /* Find the longest match, discarding those <= prev_length.
|
| 1647 | */
|
| 1648 | s->prev_length = s->match_length, s->prev_match = s->match_start;
|
| 1649 | s->match_length = MIN_MATCH-1;
|
| 1650 |
|
| 1651 | if (hash_head != NIL && s->prev_length < s->max_lazy_match &&
|
| 1652 | s->strstart - hash_head <= MAX_DIST(s)) {
|
| 1653 | /* To simplify the code, we prevent matches with the string
|
| 1654 | * of window index 0 (in particular we have to avoid a match
|
| 1655 | * of the string with itself at the start of the input file).
|
| 1656 | */
|
| 1657 | s->match_length = longest_match (s, hash_head);
|
| 1658 | /* longest_match() sets match_start */
|
| 1659 |
|
| 1660 | if (s->match_length <= 5 && (s->strategy == Z_FILTERED
|
| 1661 | #if TOO_FAR <= 32767
|
| 1662 | || (s->match_length == MIN_MATCH &&
|
| 1663 | s->strstart - s->match_start > TOO_FAR)
|
| 1664 | #endif
|
| 1665 | )) {
|
| 1666 |
|
| 1667 | /* If prev_match is also MIN_MATCH, match_start is garbage
|
| 1668 | * but we will ignore the current match anyway.
|
| 1669 | */
|
| 1670 | s->match_length = MIN_MATCH-1;
|
| 1671 | }
|
| 1672 | }
|
| 1673 | /* If there was a match at the previous step and the current
|
| 1674 | * match is not better, output the previous match:
|
| 1675 | */
|
| 1676 | if (s->prev_length >= MIN_MATCH && s->match_length <= s->prev_length) {
|
| 1677 | uInt max_insert = s->strstart + s->lookahead - MIN_MATCH;
|
| 1678 | /* Do not insert strings in hash table beyond this. */
|
| 1679 |
|
| 1680 | check_match(s, s->strstart-1, s->prev_match, s->prev_length);
|
| 1681 |
|
| 1682 | _tr_tally_dist(s, s->strstart -1 - s->prev_match,
|
| 1683 | s->prev_length - MIN_MATCH, bflush);
|
| 1684 |
|
| 1685 | /* Insert in hash table all strings up to the end of the match.
|
| 1686 | * strstart-1 and strstart are already inserted. If there is not
|
| 1687 | * enough lookahead, the last two strings are not inserted in
|
| 1688 | * the hash table.
|
| 1689 | */
|
| 1690 | s->lookahead -= s->prev_length-1;
|
| 1691 | s->prev_length -= 2;
|
| 1692 | do {
|
| 1693 | if (++s->strstart <= max_insert) {
|
| 1694 | INSERT_STRING(s, s->strstart, hash_head);
|
| 1695 | }
|
| 1696 | } while (--s->prev_length != 0);
|
| 1697 | s->match_available = 0;
|
| 1698 | s->match_length = MIN_MATCH-1;
|
| 1699 | s->strstart++;
|
| 1700 |
|
| 1701 | if (bflush) FLUSH_BLOCK(s, 0);
|
| 1702 |
|
| 1703 | } else if (s->match_available) {
|
| 1704 | /* If there was no match at the previous position, output a
|
| 1705 | * single literal. If there was a match but the current match
|
| 1706 | * is longer, truncate the previous match to a single literal.
|
| 1707 | */
|
| 1708 | Tracevv((stderr,"%c", s->window[s->strstart-1]));
|
| 1709 | _tr_tally_lit(s, s->window[s->strstart-1], bflush);
|
| 1710 | if (bflush) {
|
| 1711 | FLUSH_BLOCK_ONLY(s, 0);
|
| 1712 | }
|
| 1713 | s->strstart++;
|
| 1714 | s->lookahead--;
|
| 1715 | if (s->strm->avail_out == 0) return need_more;
|
| 1716 | } else {
|
| 1717 | /* There is no previous match to compare with, wait for
|
| 1718 | * the next step to decide.
|
| 1719 | */
|
| 1720 | s->match_available = 1;
|
| 1721 | s->strstart++;
|
| 1722 | s->lookahead--;
|
| 1723 | }
|
| 1724 | }
|
| 1725 | Assert (flush != Z_NO_FLUSH, "no flush?");
|
| 1726 | if (s->match_available) {
|
| 1727 | Tracevv((stderr,"%c", s->window[s->strstart-1]));
|
| 1728 | _tr_tally_lit(s, s->window[s->strstart-1], bflush);
|
| 1729 | s->match_available = 0;
|
| 1730 | }
|
| 1731 | FLUSH_BLOCK(s, flush == Z_FINISH);
|
| 1732 | return flush == Z_FINISH ? finish_done : block_done;
|
| 1733 | }
|
| 1734 | #endif /* FASTEST */
|
| 1735 |
|
| 1736 | /* ===========================================================================
|
| 1737 | * For Z_RLE, simply look for runs of bytes, generate matches only of distance
|
| 1738 | * one. Do not maintain a hash table. (It will be regenerated if this run of
|
| 1739 | * deflate switches away from Z_RLE.)
|
| 1740 | */
|
| 1741 | local block_state deflate_rle(s, flush)
|
| 1742 | deflate_state *s;
|
| 1743 | int flush;
|
| 1744 | {
|
| 1745 | int bflush; /* set if current block must be flushed */
|
| 1746 | uInt prev; /* byte at distance one to match */
|
| 1747 | Bytef *scan, *strend; /* scan goes up to strend for length of run */
|
| 1748 |
|
| 1749 | for (;;) {
|
| 1750 | /* Make sure that we always have enough lookahead, except
|
| 1751 | * at the end of the input file. We need MAX_MATCH bytes
|
| 1752 | * for the longest encodable run.
|
| 1753 | */
|
| 1754 | if (s->lookahead < MAX_MATCH) {
|
| 1755 | fill_window(s);
|
| 1756 | if (s->lookahead < MAX_MATCH && flush == Z_NO_FLUSH) {
|
| 1757 | return need_more;
|
| 1758 | }
|
| 1759 | if (s->lookahead == 0) break; /* flush the current block */
|
| 1760 | }
|
| 1761 |
|
| 1762 | /* See how many times the previous byte repeats */
|
| 1763 | s->match_length = 0;
|
| 1764 | if (s->lookahead >= MIN_MATCH && s->strstart > 0) {
|
| 1765 | scan = s->window + s->strstart - 1;
|
| 1766 | prev = *scan;
|
| 1767 | if (prev == *++scan && prev == *++scan && prev == *++scan) {
|
| 1768 | strend = s->window + s->strstart + MAX_MATCH;
|
| 1769 | do {
|
| 1770 | } while (prev == *++scan && prev == *++scan &&
|
| 1771 | prev == *++scan && prev == *++scan &&
|
| 1772 | prev == *++scan && prev == *++scan &&
|
| 1773 | prev == *++scan && prev == *++scan &&
|
| 1774 | scan < strend);
|
| 1775 | s->match_length = MAX_MATCH - (int)(strend - scan);
|
| 1776 | if (s->match_length > s->lookahead)
|
| 1777 | s->match_length = s->lookahead;
|
| 1778 | }
|
| 1779 | }
|
| 1780 |
|
| 1781 | /* Emit match if have run of MIN_MATCH or longer, else emit literal */
|
| 1782 | if (s->match_length >= MIN_MATCH) {
|
| 1783 | check_match(s, s->strstart, s->strstart - 1, s->match_length);
|
| 1784 |
|
| 1785 | _tr_tally_dist(s, 1, s->match_length - MIN_MATCH, bflush);
|
| 1786 |
|
| 1787 | s->lookahead -= s->match_length;
|
| 1788 | s->strstart += s->match_length;
|
| 1789 | s->match_length = 0;
|
| 1790 | } else {
|
| 1791 | /* No match, output a literal byte */
|
| 1792 | Tracevv((stderr,"%c", s->window[s->strstart]));
|
| 1793 | _tr_tally_lit (s, s->window[s->strstart], bflush);
|
| 1794 | s->lookahead--;
|
| 1795 | s->strstart++;
|
| 1796 | }
|
| 1797 | if (bflush) FLUSH_BLOCK(s, 0);
|
| 1798 | }
|
| 1799 | FLUSH_BLOCK(s, flush == Z_FINISH);
|
| 1800 | return flush == Z_FINISH ? finish_done : block_done;
|
| 1801 | }
|
| 1802 |
|
| 1803 | /* ===========================================================================
|
| 1804 | * For Z_HUFFMAN_ONLY, do not look for matches. Do not maintain a hash table.
|
| 1805 | * (It will be regenerated if this run of deflate switches away from Huffman.)
|
| 1806 | */
|
| 1807 | local block_state deflate_huff(s, flush)
|
| 1808 | deflate_state *s;
|
| 1809 | int flush;
|
| 1810 | {
|
| 1811 | int bflush; /* set if current block must be flushed */
|
| 1812 |
|
| 1813 | for (;;) {
|
| 1814 | /* Make sure that we have a literal to write. */
|
| 1815 | if (s->lookahead == 0) {
|
| 1816 | fill_window(s);
|
| 1817 | if (s->lookahead == 0) {
|
| 1818 | if (flush == Z_NO_FLUSH)
|
| 1819 | return need_more;
|
| 1820 | break; /* flush the current block */
|
| 1821 | }
|
| 1822 | }
|
| 1823 |
|
| 1824 | /* Output a literal byte */
|
| 1825 | s->match_length = 0;
|
| 1826 | Tracevv((stderr,"%c", s->window[s->strstart]));
|
| 1827 | _tr_tally_lit (s, s->window[s->strstart], bflush);
|
| 1828 | s->lookahead--;
|
| 1829 | s->strstart++;
|
| 1830 | if (bflush) FLUSH_BLOCK(s, 0);
|
| 1831 | }
|
| 1832 | FLUSH_BLOCK(s, flush == Z_FINISH);
|
| 1833 | return flush == Z_FINISH ? finish_done : block_done;
|
| 1834 | }
|