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deflate.cpp
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//#include "../game/q_shared.h"
//#include "../qcommon/qcommon.h"
#include "zip.h"
#include "deflate.h"
#include <string.h>
#include <assert.h>
#include <stdlib.h>
#ifdef _TIMING
int totalDeflateTime[Z_MAX_COMPRESSION + 1];
int totalDeflateCount[Z_MAX_COMPRESSION + 1];
#endif
// If you use the zlib library in a product, an acknowledgment is welcome
// in the documentation of your product. If for some reason you cannot
// include such an acknowledgment, I would appreciate that you keep this
// copyright string in the executable of your product.
const char deflate_copyright[] = "Deflate 1.1.3 Copyright 1995-1998 Jean-loup Gailly ";
static const char *deflate_error = "OK";
// ALGORITHM
//
// The "deflation" process depends on being able to identify portions
// of the input text which are identical to earlier input (within a
// sliding window trailing behind the input currently being processed).
//
// The most straightforward technique turns out to be the fastest for
// most input files: try all possible matches and select the longest.
// The key feature of this algorithm is that insertions into the string
// dictionary are very simple and thus fast, and deletions are avoided
// completely. Insertions are performed at each input character, whereas
// string matches are performed only when the previous match ends. So it
// is preferable to spend more time in matches to allow very fast string
// insertions and avoid deletions. The matching algorithm for small
// strings is inspired from that of Rabin & Karp. A brute force approach
// is used to find longer strings when a small match has been found.
// A similar algorithm is used in comic (by Jan-Mark Wams) and freeze
// (by Leonid Broukhis).
//
// ACKNOWLEDGEMENTS
//
// The idea of lazy evaluation of matches is due to Jan-Mark Wams, and
// I found it in 'freeze' written by Leonid Broukhis.
// Thanks to many people for bug reports and testing.
//
// REFERENCES
//
// Deutsch, L.P.,"DEFLATE Compressed Data Format Specification".
// Available in ftp://ds.internic.net/rfc/rfc1951.txt
//
// A description of the Rabin and Karp algorithm is given in the book
// "Algorithms" by R. Sedgewick, Addison-Wesley, p252.
//
// Fiala,E.R., and Greene,D.H.
// Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595
// ===============================================================================
// A word is an index in the character window. We use short instead of int to
// save space in the various tables. ulong is used only for parameter passing.
// The static literal tree. Since the bit lengths are imposed, there is no
// need for the L_CODES extra codes used during heap construction. However
// The codes 286 and 287 are needed to build a canonical tree (see _tr_init
// below).
static const ct_data static_ltree[L_CODES + 2] =
{
{{ 12 }, { 8 }}, {{ 140 }, { 8 }}, {{ 76 }, { 8 }}, {{ 204 }, { 8 }}, {{ 44 }, { 8 }},
{{ 172 }, { 8 }}, {{ 108 }, { 8 }}, {{ 236 }, { 8 }}, {{ 28 }, { 8 }}, {{ 156 }, { 8 }},
{{ 92 }, { 8 }}, {{ 220 }, { 8 }}, {{ 60 }, { 8 }}, {{ 188 }, { 8 }}, {{ 124 }, { 8 }},
{{ 252 }, { 8 }}, {{ 2 }, { 8 }}, {{ 130 }, { 8 }}, {{ 66 }, { 8 }}, {{ 194 }, { 8 }},
{{ 34 }, { 8 }}, {{ 162 }, { 8 }}, {{ 98 }, { 8 }}, {{ 226 }, { 8 }}, {{ 18 }, { 8 }},
{{ 146 }, { 8 }}, {{ 82 }, { 8 }}, {{ 210 }, { 8 }}, {{ 50 }, { 8 }}, {{ 178 }, { 8 }},
{{ 114 }, { 8 }}, {{ 242 }, { 8 }}, {{ 10 }, { 8 }}, {{ 138 }, { 8 }}, {{ 74 }, { 8 }},
{{ 202 }, { 8 }}, {{ 42 }, { 8 }}, {{ 170 }, { 8 }}, {{ 106 }, { 8 }}, {{ 234 }, { 8 }},
{{ 26 }, { 8 }}, {{ 154 }, { 8 }}, {{ 90 }, { 8 }}, {{ 218 }, { 8 }}, {{ 58 }, { 8 }},
{{ 186 }, { 8 }}, {{ 122 }, { 8 }}, {{ 250 }, { 8 }}, {{ 6 }, { 8 }}, {{ 134 }, { 8 }},
{{ 70 }, { 8 }}, {{ 198 }, { 8 }}, {{ 38 }, { 8 }}, {{ 166 }, { 8 }}, {{ 102 }, { 8 }},
{{ 230 }, { 8 }}, {{ 22 }, { 8 }}, {{ 150 }, { 8 }}, {{ 86 }, { 8 }}, {{ 214 }, { 8 }},
{{ 54 }, { 8 }}, {{ 182 }, { 8 }}, {{ 118 }, { 8 }}, {{ 246 }, { 8 }}, {{ 14 }, { 8 }},
{{ 142 }, { 8 }}, {{ 78 }, { 8 }}, {{ 206 }, { 8 }}, {{ 46 }, { 8 }}, {{ 174 }, { 8 }},
{{ 110 }, { 8 }}, {{ 238 }, { 8 }}, {{ 30 }, { 8 }}, {{ 158 }, { 8 }}, {{ 94 }, { 8 }},
{{ 222 }, { 8 }}, {{ 62 }, { 8 }}, {{ 190 }, { 8 }}, {{ 126 }, { 8 }}, {{ 254 }, { 8 }},
{{ 1 }, { 8 }}, {{ 129 }, { 8 }}, {{ 65 }, { 8 }}, {{ 193 }, { 8 }}, {{ 33 }, { 8 }},
{{ 161 }, { 8 }}, {{ 97 }, { 8 }}, {{ 225 }, { 8 }}, {{ 17 }, { 8 }}, {{ 145 }, { 8 }},
{{ 81 }, { 8 }}, {{ 209 }, { 8 }}, {{ 49 }, { 8 }}, {{ 177 }, { 8 }}, {{ 113 }, { 8 }},
{{ 241 }, { 8 }}, {{ 9 }, { 8 }}, {{ 137 }, { 8 }}, {{ 73 }, { 8 }}, {{ 201 }, { 8 }},
{{ 41 }, { 8 }}, {{ 169 }, { 8 }}, {{ 105 }, { 8 }}, {{ 233 }, { 8 }}, {{ 25 }, { 8 }},
{{ 153 }, { 8 }}, {{ 89 }, { 8 }}, {{ 217 }, { 8 }}, {{ 57 }, { 8 }}, {{ 185 }, { 8 }},
{{ 121 }, { 8 }}, {{ 249 }, { 8 }}, {{ 5 }, { 8 }}, {{ 133 }, { 8 }}, {{ 69 }, { 8 }},
{{ 197 }, { 8 }}, {{ 37 }, { 8 }}, {{ 165 }, { 8 }}, {{ 101 }, { 8 }}, {{ 229 }, { 8 }},
{{ 21 }, { 8 }}, {{ 149 }, { 8 }}, {{ 85 }, { 8 }}, {{ 213 }, { 8 }}, {{ 53 }, { 8 }},
{{ 181 }, { 8 }}, {{ 117 }, { 8 }}, {{ 245 }, { 8 }}, {{ 13 }, { 8 }}, {{ 141 }, { 8 }},
{{ 77 }, { 8 }}, {{ 205 }, { 8 }}, {{ 45 }, { 8 }}, {{ 173 }, { 8 }}, {{ 109 }, { 8 }},
{{ 237 }, { 8 }}, {{ 29 }, { 8 }}, {{ 157 }, { 8 }}, {{ 93 }, { 8 }}, {{ 221 }, { 8 }},
{{ 61 }, { 8 }}, {{ 189 }, { 8 }}, {{ 125 }, { 8 }}, {{ 253 }, { 8 }}, {{ 19 }, { 9 }},
{{ 275 }, { 9 }}, {{ 147 }, { 9 }}, {{ 403 }, { 9 }}, {{ 83 }, { 9 }}, {{ 339 }, { 9 }},
{{ 211 }, { 9 }}, {{ 467 }, { 9 }}, {{ 51 }, { 9 }}, {{ 307 }, { 9 }}, {{ 179 }, { 9 }},
{{ 435 }, { 9 }}, {{ 115 }, { 9 }}, {{ 371 }, { 9 }}, {{ 243 }, { 9 }}, {{ 499 }, { 9 }},
{{ 11 }, { 9 }}, {{ 267 }, { 9 }}, {{ 139 }, { 9 }}, {{ 395 }, { 9 }}, {{ 75 }, { 9 }},
{{ 331 }, { 9 }}, {{ 203 }, { 9 }}, {{ 459 }, { 9 }}, {{ 43 }, { 9 }}, {{ 299 }, { 9 }},
{{ 171 }, { 9 }}, {{ 427 }, { 9 }}, {{ 107 }, { 9 }}, {{ 363 }, { 9 }}, {{ 235 }, { 9 }},
{{ 491 }, { 9 }}, {{ 27 }, { 9 }}, {{ 283 }, { 9 }}, {{ 155 }, { 9 }}, {{ 411 }, { 9 }},
{{ 91 }, { 9 }}, {{ 347 }, { 9 }}, {{ 219 }, { 9 }}, {{ 475 }, { 9 }}, {{ 59 }, { 9 }},
{{ 315 }, { 9 }}, {{ 187 }, { 9 }}, {{ 443 }, { 9 }}, {{ 123 }, { 9 }}, {{ 379 }, { 9 }},
{{ 251 }, { 9 }}, {{ 507 }, { 9 }}, {{ 7 }, { 9 }}, {{ 263 }, { 9 }}, {{ 135 }, { 9 }},
{{ 391 }, { 9 }}, {{ 71 }, { 9 }}, {{ 327 }, { 9 }}, {{ 199 }, { 9 }}, {{ 455 }, { 9 }},
{{ 39 }, { 9 }}, {{ 295 }, { 9 }}, {{ 167 }, { 9 }}, {{ 423 }, { 9 }}, {{ 103 }, { 9 }},
{{ 359 }, { 9 }}, {{ 231 }, { 9 }}, {{ 487 }, { 9 }}, {{ 23 }, { 9 }}, {{ 279 }, { 9 }},
{{ 151 }, { 9 }}, {{ 407 }, { 9 }}, {{ 87 }, { 9 }}, {{ 343 }, { 9 }}, {{ 215 }, { 9 }},
{{ 471 }, { 9 }}, {{ 55 }, { 9 }}, {{ 311 }, { 9 }}, {{ 183 }, { 9 }}, {{ 439 }, { 9 }},
{{ 119 }, { 9 }}, {{ 375 }, { 9 }}, {{ 247 }, { 9 }}, {{ 503 }, { 9 }}, {{ 15 }, { 9 }},
{{ 271 }, { 9 }}, {{ 143 }, { 9 }}, {{ 399 }, { 9 }}, {{ 79 }, { 9 }}, {{ 335 }, { 9 }},
{{ 207 }, { 9 }}, {{ 463 }, { 9 }}, {{ 47 }, { 9 }}, {{ 303 }, { 9 }}, {{ 175 }, { 9 }},
{{ 431 }, { 9 }}, {{ 111 }, { 9 }}, {{ 367 }, { 9 }}, {{ 239 }, { 9 }}, {{ 495 }, { 9 }},
{{ 31 }, { 9 }}, {{ 287 }, { 9 }}, {{ 159 }, { 9 }}, {{ 415 }, { 9 }}, {{ 95 }, { 9 }},
{{ 351 }, { 9 }}, {{ 223 }, { 9 }}, {{ 479 }, { 9 }}, {{ 63 }, { 9 }}, {{ 319 }, { 9 }},
{{ 191 }, { 9 }}, {{ 447 }, { 9 }}, {{ 127 }, { 9 }}, {{ 383 }, { 9 }}, {{ 255 }, { 9 }},
{{ 511 }, { 9 }}, {{ 0 }, { 7 }}, {{ 64 }, { 7 }}, {{ 32 }, { 7 }}, {{ 96 }, { 7 }},
{{ 16 }, { 7 }}, {{ 80 }, { 7 }}, {{ 48 }, { 7 }}, {{ 112 }, { 7 }}, {{ 8 }, { 7 }},
{{ 72 }, { 7 }}, {{ 40 }, { 7 }}, {{ 104 }, { 7 }}, {{ 24 }, { 7 }}, {{ 88 }, { 7 }},
{{ 56 }, { 7 }}, {{ 120 }, { 7 }}, {{ 4 }, { 7 }}, {{ 68 }, { 7 }}, {{ 36 }, { 7 }},
{{ 100 }, { 7 }}, {{ 20 }, { 7 }}, {{ 84 }, { 7 }}, {{ 52 }, { 7 }}, {{ 116 }, { 7 }},
{{ 3 }, { 8 }}, {{ 131 }, { 8 }}, {{ 67 }, { 8 }}, {{ 195 }, { 8 }}, {{ 35 }, { 8 }},
{{ 163 }, { 8 }}, {{ 99 }, { 8 }}, {{ 227 }, { 8 }}
};
// The static distance tree. (Actually a trivial tree since all codes use 5 bits.)
static const ct_data static_dtree[D_CODES] =
{
{{ 0 }, { 5 }}, {{ 16 }, { 5 }}, {{ 8 },{ 5 }}, {{ 24 },{ 5 }}, {{ 4 },{ 5 }},
{{ 20 }, { 5 }}, {{ 12 }, { 5 }}, {{ 28 },{ 5 }}, {{ 2 },{ 5 }}, {{ 18 },{ 5 }},
{{ 10 }, { 5 }}, {{ 26 }, { 5 }}, {{ 6 },{ 5 }}, {{ 22 },{ 5 }}, {{ 14 },{ 5 }},
{{ 30 }, { 5 }}, {{ 1 }, { 5 }}, {{ 17 },{ 5 }}, {{ 9 },{ 5 }}, {{ 25 },{ 5 }},
{{ 5 }, { 5 }}, {{ 21 }, { 5 }}, {{ 13 },{ 5 }}, {{ 29 },{ 5 }}, {{ 3 },{ 5 }},
{{ 19 }, { 5 }}, {{ 11 }, { 5 }}, {{ 27 },{ 5 }}, {{ 7 },{ 5 }}, {{ 23 },{ 5 }}
};
// Distance codes. The first 256 values correspond to the distances
// 3 .. 258, the last 256 values correspond to the top 8 bits of
// the 15 bit distances.
static const byte tr_dist_code[DIST_CODE_LEN] =
{
0, 1, 2, 3, 4, 4, 5, 5, 6, 6, 6, 6, 7, 7, 7, 7, 8, 8, 8, 8,
8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10,
10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11,
11, 11, 11, 11, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12,
12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 12, 13, 13, 13, 13,
13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13, 13,
13, 13, 13, 13, 13, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14,
14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15,
15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 15, 0, 0, 16, 17,
18, 18, 19, 19, 20, 20, 20, 20, 21, 21, 21, 21, 22, 22, 22, 22, 22, 22, 22, 22,
23, 23, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28, 28,
28, 28, 28, 28, 28, 28, 28, 28, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29,
29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29, 29
};
// length code for each normalized match length (0 == MIN_MATCH)
static const byte tr_length_code[MAX_MATCH - MIN_MATCH + 1] =
{
0, 1, 2, 3, 4, 5, 6, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 12, 12,
13, 13, 13, 13, 14, 14, 14, 14, 15, 15, 15, 15, 16, 16, 16, 16, 16, 16, 16, 16,
17, 17, 17, 17, 17, 17, 17, 17, 18, 18, 18, 18, 18, 18, 18, 18, 19, 19, 19, 19,
19, 19, 19, 19, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20, 20,
21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 21, 22, 22, 22, 22,
22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 22, 23, 23, 23, 23, 23, 23, 23, 23,
23, 23, 23, 23, 23, 23, 23, 23, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24, 24,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25,
25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 25, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26, 26,
26, 26, 26, 26, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27,
27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 27, 28
};
// First normalized length for each code (0 = MIN_MATCH)
static const int base_length[LENGTH_CODES] =
{
0, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 20, 24, 28, 32, 40, 48, 56,
64, 80, 96, 112, 128, 160, 192, 224, 0
};
// First normalized distance for each code (0 = distance of 1)
static const int base_dist[D_CODES] =
{
0, 1, 2, 3, 4, 6, 8, 12, 16, 24,
32, 48, 64, 96, 128, 192, 256, 384, 512, 768,
1024, 1536, 2048, 3072, 4096, 6144, 8192, 12288, 16384, 24576
};
// Note: the deflate() code requires max_lazy >= MIN_MATCH and max_chain >= 4
// For deflate_fast() (levels <= 3) good is ignored and lazy has a different
// meaning.
static block_state deflate_stored(deflate_state *s, EFlush flush);
static block_state deflate_fast(deflate_state *s, EFlush flush);
static block_state deflate_slow(deflate_state *s, EFlush flush);
// Values for max_lazy_match, good_match and max_chain_length, depending on
// the desired pack level (0..9). The values given below have been tuned to
// exclude worst case performance for pathological files. Better values may be
// found for specific files.
static const config configuration_table[10] =
{
// good lazy nice chain
{ 0, 0, 0, 0, deflate_stored }, // store only
{ 4, 4, 8, 4, deflate_fast }, // maximum speed, no lazy matches
{ 4, 5, 16, 8, deflate_fast },
{ 4, 6, 32, 32, deflate_fast },
{ 4, 4, 16, 16, deflate_slow }, // lazy matches
{ 8, 16, 32, 32, deflate_slow },
{ 8, 16, 128, 128, deflate_slow },
{ 8, 32, 128, 256, deflate_slow },
{ 32, 128, 258, 1024, deflate_slow },
{ 32, 258, 258, 4096, deflate_slow } // maximum compression
};
// extra bits for each length code
static ulong extra_lbits[LENGTH_CODES] =
{
0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 4, 4, 4, 4, 5, 5, 5, 5, 0
};
// Extra bits for distance codes
const ulong extra_dbits[D_CODES] =
{
0, 0, 0, 0, 1, 1, 2, 2, 3, 3, 4, 4, 5, 5, 6, 6, 7, 7, 8, 8, 9, 9, 10, 10, 11, 11, 12, 12, 13, 13
};
// extra bits for each bit length code
static ulong extra_blbits[BL_CODES] =
{
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2, 3, 7
};
// The lengths of the bit length codes are sent in order of decreasing
// probability, to avoid transmitting the lengths for unused bit length codes.
static const byte bl_order[BL_CODES] =
{
16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15
};
static static_tree_desc static_l_desc =
{
static_ltree, extra_lbits, LITERALS + 1, L_CODES, MAX_WBITS
};
static static_tree_desc static_d_desc =
{
static_dtree, extra_dbits, 0, D_CODES, MAX_WBITS
};
static static_tree_desc static_bl_desc =
{
NULL, extra_blbits, 0, BL_CODES, MAX_BL_BITS
};
// ===============================================================================
// Output bytes to the output stream. Inlined for speed
// ===============================================================================
inline void put_byte(deflate_state *s, const byte c)
{
s->pending_buf[s->pending++] = c;
}
// Fixme: write as 1 short
inline void put_short(deflate_state *s, const word w)
{
s->pending_buf[s->pending++] = (byte)(w & 0xff);
s->pending_buf[s->pending++] = (byte)(w >> 8);
}
inline void put_shortMSB(deflate_state *s, const word w)
{
s->pending_buf[s->pending++] = (byte)(w >> 8);
s->pending_buf[s->pending++] = (byte)(w & 0xff);
}
inline void put_longMSB(deflate_state *s, const ulong l)
{
s->pending_buf[s->pending++] = (byte)(l >> 24);
s->pending_buf[s->pending++] = (byte)(l >> 16);
s->pending_buf[s->pending++] = (byte)(l >> 8);
s->pending_buf[s->pending++] = (byte)(l & 0xff);
}
// ===============================================================================
// Send a value on a given number of bits.
// IN assertion: length <= 16 and value fits in length bits.
// ===============================================================================
static void send_bits(deflate_state *s, const ulong val, const ulong len)
{
assert(len <= 16);
assert(val <= 65536);
if(s->bi_valid > (BUF_SIZE - len))
{
s->bi_buf |= val << s->bi_valid;
put_short(s, s->bi_buf);
s->bi_buf = (word)(val >> (BUF_SIZE - s->bi_valid));
s->bi_valid += len - BUF_SIZE;
}
else
{
s->bi_buf |= val << s->bi_valid;
s->bi_valid += len;
}
}
// ===============================================================================
// Initialize a new block.
// ===============================================================================
static void init_block(deflate_state *s)
{
int n; // iterates over tree elements
// Initialize the trees.
for(n = 0; n < L_CODES; n++)
{
s->dyn_ltree[n].fc.freq = 0;
}
for(n = 0; n < D_CODES; n++)
{
s->dyn_dtree[n].fc.freq = 0;
}
for(n = 0; n < BL_CODES; n++)
{
s->bl_tree[n].fc.freq = 0;
}
s->dyn_ltree[END_BLOCK].fc.freq = 1;
s->opt_len = 0;
s->static_len = 0;
s->last_lit = 0;
s->matches = 0;
}
// ===============================================================================
// Initialize the tree data structures for a new zlib stream.
// ===============================================================================
static void tr_init(deflate_state *s)
{
s->l_desc.dyn_tree = s->dyn_ltree;
s->l_desc.stat_desc = &static_l_desc;
s->d_desc.dyn_tree = s->dyn_dtree;
s->d_desc.stat_desc = &static_d_desc;
s->bl_desc.dyn_tree = s->bl_tree;
s->bl_desc.stat_desc = &static_bl_desc;
s->bi_buf = 0;
s->bi_valid = 0;
// enough lookahead for inflate
s->last_eob_len = 8;
// Initialize the first block of the first file:
init_block(s);
}
// ===============================================================================
// Compares to subtrees, using the tree depth as tie breaker when
// the subtrees have equal frequency. This minimizes the worst case length.
// ===============================================================================
static bool smaller(ct_data *tree, ulong son, ulong daughter, byte *depth)
{
if(tree[son].fc.freq < tree[daughter].fc.freq)
{
return(true);
}
if((tree[son].fc.freq == tree[daughter].fc.freq) && (depth[son] <= depth[daughter]))
{
return(true);
}
return(false);
}
// ===============================================================================
// Restore the heap property by moving down the tree starting at node k,
// exchanging a node with the smallest of its two sons if necessary, stopping
// when the heap property is re-established (each father smaller than its
// two sons).
// ===============================================================================
static void pqdownheap(deflate_state *s, ct_data *tree, ulong node)
{
ulong base;
ulong sibling; // left son of node
base = s->heap[node];
sibling = node << 1;
while(sibling <= s->heap_len)
{
// Set sibling to the smallest of the two children
if((sibling < s->heap_len) && smaller(tree, s->heap[sibling + 1], s->heap[sibling], s->depth))
{
sibling++;
}
// Exit if base is smaller than both sons
if(smaller(tree, base, s->heap[sibling], s->depth))
{
break;
}
// Exchange base with the smallest son
s->heap[node] = s->heap[sibling];
node = sibling;
// And continue down the tree, setting sibling to the left son of base
sibling <<= 1;
}
s->heap[node] = base;
}
// ===============================================================================
// Compute the optimal bit lengths for a tree and update the total bit length
// for the current block.
// IN assertion: the fields freq and dad are set, heap[heap_max] and
// above are the tree nodes sorted by increasing frequency.
// OUT assertions: the field len is set to the optimal bit length, the
// array bl_count contains the frequencies for each bit length.
// The length opt_len is updated; static_len is also updated if stree is
// not null.
// ===============================================================================
static void gen_bitlen(deflate_state *s, tree_desc *desc)
{
const ct_data *stree;
const ulong *extra;
ulong base;
ulong max_length;
ulong heapIdx; // heap index
ulong n, m; // iterate over the tree elements
ulong bits; // bit length
ulong xbits; // extra bits
word freq; // frequency
ulong overflow; // number of elements with bit length too large
stree = desc->stat_desc->static_tree;
extra = desc->stat_desc->extra_bits;
base = desc->stat_desc->extra_base;
max_length = desc->stat_desc->max_length;
overflow = 0;
for(bits = 0; bits <= MAX_WBITS; bits++)
{
s->bl_count[bits] = 0;
}
// In a first pass, compute the optimal bit lengths (which may
// overflow in the case of the bit length tree).
// root of the heap
desc->dyn_tree[s->heap[s->heap_max]].dl.len = 0;
for(heapIdx = s->heap_max + 1; heapIdx < HEAP_SIZE; heapIdx++)
{
n = s->heap[heapIdx];
bits = desc->dyn_tree[desc->dyn_tree[n].dl.dad].dl.len + 1;
if(bits > max_length)
{
bits = max_length;
overflow++;
}
// We overwrite tree[n].dl.dad which is no longer needed
desc->dyn_tree[n].dl.len = (word)bits;
// not a leaf node
if(n > desc->max_code)
{
continue;
}
s->bl_count[bits]++;
xbits = 0;
if(n >= base)
{
xbits = extra[n - base];
}
freq = desc->dyn_tree[n].fc.freq;
s->opt_len += freq * (bits + xbits);
if(stree)
{
s->static_len += freq * (stree[n].dl.len + xbits);
}
}
if(!overflow)
{
return;
}
// Find the first bit length which could increase
do
{
bits = max_length - 1;
while(!s->bl_count[bits])
{
bits--;
}
// move one leaf down the tree
s->bl_count[bits]--;
// move one overflow item as its brother
s->bl_count[bits + 1] += 2;
// The brother of the overflow item also moves one step up,
// but this does not affect bl_count[max_length]
s->bl_count[max_length]--;
overflow -= 2;
}
while(overflow > 0);
// Now recompute all bit lengths, scanning in increasing frequency.
// heapIdx is still equal to HEAP_SIZE. (It is simpler to reconstruct all
// lengths instead of fixing only the wrong ones. This idea is taken
// from 'ar' written by Haruhiko Okumura.)
for(bits = max_length; bits; bits--)
{
n = s->bl_count[bits];
while(n)
{
m = s->heap[--heapIdx];
if(m > desc->max_code)
{
continue;
}
if(desc->dyn_tree[m].dl.len != bits)
{
s->opt_len += (bits - desc->dyn_tree[m].dl.len) * desc->dyn_tree[m].fc.freq;
desc->dyn_tree[m].dl.len = (word)bits;
}
n--;
}
}
}
// ===============================================================================
// Flush the bit buffer and align the output on a byte boundary
// ===============================================================================
static void bi_windup(deflate_state *s)
{
if(s->bi_valid > 8)
{
put_short(s, s->bi_buf);
}
else if(s->bi_valid > 0)
{
put_byte(s, (byte)s->bi_buf);
}
s->bi_buf = 0;
s->bi_valid = 0;
}
// ===============================================================================
// Reverse the first len bits of a code, using straightforward code (a faster
// method would use a table)
// ===============================================================================
static ulong bi_reverse(ulong code, ulong len)
{
ulong res;
assert(1 <= len);
assert(len <= 15);
res = 0;
do
{
res |= code & 1;
code >>= 1;
res <<= 1;
}
while(--len > 0);
return(res >> 1);
}
// ===============================================================================
// Generate the codes for a given tree and bit counts (which need not be optimal).
// IN assertion: the array bl_count contains the bit length statistics for
// the given tree and the field len is set for all tree elements.
// OUT assertion: the field code is set for all tree elements of non zero code length.
// ===============================================================================
static void gen_codes(ct_data *tree, ulong max_code, word *bl_count)
{
word next_code[MAX_WBITS + 1]; // next code value for each bit length
word code; // running code value
ulong bits; // bit index
ulong codes; // code index
ulong len;
// The distribution counts are first used to generate the code values
// without bit reversal.
code = 0;
for(bits = 1; bits <= MAX_WBITS; bits++)
{
code = (word)((code + bl_count[bits - 1]) << 1);
next_code[bits] = code;
}
// Check that the bit counts in bl_count are consistent. The last code
// must be all ones.
for(codes = 0; codes <= max_code; codes++)
{
len = tree[codes].dl.len;
if(!len)
{
continue;
}
// Now reverse the bits
tree[codes].fc.code = (word)bi_reverse(next_code[len]++, len);
}
}
// ===============================================================================
// Construct one Huffman tree and assigns the code bit strings and lengths.
// Update the total bit length for the current block.
// IN assertion: the field freq is set for all tree elements.
// OUT assertions: the fields len and code are set to the optimal bit length
// and corresponding code. The length opt_len is updated; static_len is
// also updated if stree is not null. The field max_code is set.
// ===============================================================================
static void build_tree(deflate_state *s, tree_desc *desc)
{
ct_data *tree;
const ct_data *stree;
ulong elems;
ulong n, m; // iterate over heap elements
ulong max_code; // largest code with non zero frequency
ulong node; // new node being created
tree = desc->dyn_tree;
stree = desc->stat_desc->static_tree;
elems = desc->stat_desc->elems;
max_code = 0;
// Construct the initial heap, with least frequent element in
// heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
// heap[0] is not used.
s->heap_len = 0;
s->heap_max = HEAP_SIZE;
for(n = 0; n < elems; n++)
{
if(tree[n].fc.freq)
{
max_code = n;
s->heap[++s->heap_len] = n;
s->depth[n] = 0;
}
else
{
tree[n].dl.len = 0;
}
}
// The pkzip format requires that at least one distance code exists,
// and that at least one bit should be sent even if there is only one
// possible code. So to avoid special checks later on we force at least
// two codes of non zero frequency.
while(s->heap_len < 2)
{
s->heap[++s->heap_len] = (max_code < 2 ? ++max_code : 0);
node = s->heap[s->heap_len];
tree[node].fc.freq = 1;
s->depth[node] = 0;
s->opt_len--;
if(stree)
{
s->static_len -= stree[node].dl.len;
}
// node is 0 or 1 so it does not have extra bits
}
desc->max_code = max_code;
// The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
// establish sub-heaps of increasing lengths:
for(n = s->heap_len >> 1; n >= 1; n--)
{
pqdownheap(s, tree, n);
}
// Construct the Huffman tree by repeatedly combining the least two
// frequent nodes.
// next internal node of the tree
node = elems;
do
{
n = s->heap[SMALLEST];
s->heap[SMALLEST] = s->heap[s->heap_len--];
pqdownheap(s, tree, SMALLEST);
m = s->heap[SMALLEST]; // m = node of next least frequency
s->heap[--s->heap_max] = n; // keep the nodes sorted by frequency
s->heap[--s->heap_max] = m;
// Create a new node father of n and m
tree[node].fc.freq = (word)(tree[n].fc.freq + tree[m].fc.freq);
if(s->depth[n] > s->depth[m])
{
s->depth[node] = s->depth[n];
}
else
{
s->depth[node] = s->depth[m];
s->depth[node]++;
}
tree[m].dl.dad = (word)node;
tree[n].dl.dad = (word)node;
// and insert the new node in the heap
s->heap[SMALLEST] = node++;
pqdownheap(s, tree, SMALLEST);
}
while(s->heap_len >= 2);
s->heap[--s->heap_max] = s->heap[SMALLEST];
// At this point, the fields freq and dad are set. We can now
// generate the bit lengths.
gen_bitlen(s, desc);
// The field len is now set, we can generate the bit codes
gen_codes (tree, max_code, s->bl_count);
}
// ===============================================================================
// Scan a literal or distance tree to determine the frequencies of the codes
// in the bit length tree.
// ===============================================================================
static void scan_tree (deflate_state *s, ct_data *tree, ulong max_code)
{
ulong n; // iterates over all tree elements
ulong prevlen; // last emitted length
ulong curlen; // length of current code
ulong nextlen; // length of next code
ulong count; // repeat count of the current code
ulong max_count; // max repeat count
ulong min_count; // min repeat count
prevlen = 0xffff;
nextlen = tree[0].dl.len;
count = 0;
max_count = 7;
min_count = 4;
if(!nextlen)
{
max_count = 138;
min_count = 3;
}
// guard
tree[max_code + 1].dl.len = (word)prevlen;
for(n = 0; n <= max_code; n++)
{
curlen = nextlen;
nextlen = tree[n + 1].dl.len;
if((++count < max_count) && (curlen == nextlen))
{
continue;
}
else if(count < min_count)
{
s->bl_tree[curlen].fc.freq += (word)count;
}
else if(curlen)
{
if(curlen != prevlen)
{
s->bl_tree[curlen].fc.freq++;
}
s->bl_tree[REP_3_6].fc.freq++;
}
else if(count <= 10)
{
s->bl_tree[REPZ_3_10].fc.freq++;
}
else
{
s->bl_tree[REPZ_11_138].fc.freq++;
}
count = 0;
prevlen = curlen;
if(!nextlen)
{
max_count = 138;
min_count = 3;
}
else if(curlen == nextlen)
{
max_count = 6;
min_count = 3;
}
else
{
max_count = 7;
min_count = 4;
}
}
}
// ===============================================================================
// Send a literal or distance tree in compressed form, using the codes in bl_tree.
// ===============================================================================
static void send_tree(deflate_state *s, ct_data *tree, ulong max_code)
{
ulong n; // iterates over all tree elements
ulong prevlen; // last emitted length
ulong curlen; // length of current code
ulong nextlen; // length of next code
ulong count; // repeat count of the current code
ulong max_count; // max repeat count
ulong min_count; // min repeat count
prevlen = 0xffff;
nextlen = tree[0].dl.len;
count = 0;
max_count = 7;
min_count = 4;
if(!nextlen)
{
max_count = 138;
min_count = 3;
}
for(n = 0; n <= max_code; n++)
{
curlen = nextlen;
nextlen = tree[n + 1].dl.len;
if((++count < max_count) && (curlen == nextlen))
{
continue;
}
else if(count < min_count)
{
do
{
send_bits(s, s->bl_tree[curlen].fc.code, s->bl_tree[curlen].dl.len);
}
while(--count);
}
else if(curlen)
{
if(curlen != prevlen)
{
send_bits(s, s->bl_tree[curlen].fc.code, s->bl_tree[curlen].dl.len);
count--;
}
send_bits(s, s->bl_tree[REP_3_6].fc.code, s->bl_tree[REP_3_6].dl.len);
send_bits(s, count - 3, 2);
}
else if(count <= 10)
{
send_bits(s, s->bl_tree[REPZ_3_10].fc.code, s->bl_tree[REPZ_3_10].dl.len);
send_bits(s, count - 3, 3);
}
else
{
send_bits(s, s->bl_tree[REPZ_11_138].fc.code, s->bl_tree[REPZ_11_138].dl.len);
send_bits(s, count - 11, 7);
}
count = 0;
prevlen = curlen;
if(!nextlen)
{
max_count = 138;
min_count = 3;
}
else if(curlen == nextlen)
{
max_count = 6;
min_count = 3;
}
else
{
max_count = 7;
min_count = 4;
}
}
}
// ===============================================================================
// Construct the Huffman tree for the bit lengths and return the index in
// bl_order of the last bit length code to send.
// ===============================================================================
static ulong build_bl_tree(deflate_state *s)
{
ulong max_blindex; // index of last bit length code of non zero freq
// Determine the bit length frequencies for literal and distance trees
scan_tree(s, s->dyn_ltree, s->l_desc.max_code);
scan_tree(s, s->dyn_dtree, s->d_desc.max_code);
// Build the bit length tree
build_tree(s, &s->bl_desc);
// opt_len now includes the length of the tree representations, except
// the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
// Determine the number of bit length codes to send. The pkzip format
// requires that at least 4 bit length codes be sent. (appnote.txt says
// 3 but the actual value used is 4.)
for(max_blindex = BL_CODES - 1; max_blindex >= 3; max_blindex--)
{
if(s->bl_tree[bl_order[max_blindex]].dl.len)
{
break;
}
}
// Update opt_len to include the bit length tree and counts
s->opt_len += 3 * (max_blindex + 1) + 5 + 5 + 4;
return(max_blindex);
}
// ===========================================================================
// Send the header for a block using dynamic Huffman trees: the counts, the
// lengths of the bit length codes, the literal tree and the distance tree.
// IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
// ===========================================================================
static void send_all_trees(deflate_state *s, ulong lcodes, ulong dcodes, ulong blcodes)
{
ulong rank; // index in bl_order
// not +255 as stated in appnote.txt
send_bits(s, lcodes - 257, 5);
send_bits(s, dcodes - 1, 5);
// not -3 as stated in appnote.txt
send_bits(s, blcodes - 4, 4);
for(rank = 0; rank < blcodes; rank++)
{
send_bits(s, s->bl_tree[bl_order[rank]].dl.len, 3);
}
// literal tree
send_tree(s, (ct_data *)s->dyn_ltree, lcodes - 1);
// distance tree
send_tree(s, (ct_data *)s->dyn_dtree, dcodes - 1);
}
// ===========================================================================
// Send the block data compressed using the given Huffman trees
// ===========================================================================
static void compress_block(deflate_state *s, const ct_data *ltree, const ct_data *dtree)
{
ulong dist; // distance of matched string
ulong lenCount; // match length or unmatched char (if dist == 0)
ulong lenIdx; // running index in l_buf
ulong code; // the code to send
ulong extra; // number of extra bits to send
lenIdx = 0;
if(s->last_lit)
{
do
{
dist = s->d_buf[lenIdx];
lenCount = s->l_buf[lenIdx++];
if(!dist)
{
// send a literal byte
send_bits(s, ltree[lenCount].fc.code, ltree[lenCount].dl.len);
}
else
{
// Here, lenCount is the match length - MIN_MATCH
code = tr_length_code[lenCount];
// send the length code
send_bits(s, ltree[code + LITERALS + 1].fc.code, ltree[code + LITERALS + 1].dl.len);