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annotate libs/zlib/trees.c @ 32:622f61160016

find changesets by author, revision, files, or words in the commit message
ok this fixes it but why?
author John Tsiombikas <nuclear@member.fsf.org>
date Fri, 09 Oct 2015 05:17:11 +0300
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children
rev   line source
nuclear@2 1 /* trees.c -- output deflated data using Huffman coding
nuclear@2 2 * Copyright (C) 1995-2005 Jean-loup Gailly
nuclear@2 3 * For conditions of distribution and use, see copyright notice in zlib.h
nuclear@2 4 */
nuclear@2 5
nuclear@2 6 /*
nuclear@2 7 * ALGORITHM
nuclear@2 8 *
nuclear@2 9 * The "deflation" process uses several Huffman trees. The more
nuclear@2 10 * common source values are represented by shorter bit sequences.
nuclear@2 11 *
nuclear@2 12 * Each code tree is stored in a compressed form which is itself
nuclear@2 13 * a Huffman encoding of the lengths of all the code strings (in
nuclear@2 14 * ascending order by source values). The actual code strings are
nuclear@2 15 * reconstructed from the lengths in the inflate process, as described
nuclear@2 16 * in the deflate specification.
nuclear@2 17 *
nuclear@2 18 * REFERENCES
nuclear@2 19 *
nuclear@2 20 * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
nuclear@2 21 * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
nuclear@2 22 *
nuclear@2 23 * Storer, James A.
nuclear@2 24 * Data Compression: Methods and Theory, pp. 49-50.
nuclear@2 25 * Computer Science Press, 1988. ISBN 0-7167-8156-5.
nuclear@2 26 *
nuclear@2 27 * Sedgewick, R.
nuclear@2 28 * Algorithms, p290.
nuclear@2 29 * Addison-Wesley, 1983. ISBN 0-201-06672-6.
nuclear@2 30 */
nuclear@2 31
nuclear@2 32 /* @(#) $Id$ */
nuclear@2 33
nuclear@2 34 /* #define GEN_TREES_H */
nuclear@2 35
nuclear@2 36 #include "deflate.h"
nuclear@2 37
nuclear@2 38 #ifdef DEBUG
nuclear@2 39 # include <ctype.h>
nuclear@2 40 #endif
nuclear@2 41
nuclear@2 42 /* ===========================================================================
nuclear@2 43 * Constants
nuclear@2 44 */
nuclear@2 45
nuclear@2 46 #define MAX_BL_BITS 7
nuclear@2 47 /* Bit length codes must not exceed MAX_BL_BITS bits */
nuclear@2 48
nuclear@2 49 #define END_BLOCK 256
nuclear@2 50 /* end of block literal code */
nuclear@2 51
nuclear@2 52 #define REP_3_6 16
nuclear@2 53 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
nuclear@2 54
nuclear@2 55 #define REPZ_3_10 17
nuclear@2 56 /* repeat a zero length 3-10 times (3 bits of repeat count) */
nuclear@2 57
nuclear@2 58 #define REPZ_11_138 18
nuclear@2 59 /* repeat a zero length 11-138 times (7 bits of repeat count) */
nuclear@2 60
nuclear@2 61 local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
nuclear@2 62 = {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};
nuclear@2 63
nuclear@2 64 local const int extra_dbits[D_CODES] /* extra bits for each distance code */
nuclear@2 65 = {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};
nuclear@2 66
nuclear@2 67 local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
nuclear@2 68 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
nuclear@2 69
nuclear@2 70 local const uch bl_order[BL_CODES]
nuclear@2 71 = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
nuclear@2 72 /* The lengths of the bit length codes are sent in order of decreasing
nuclear@2 73 * probability, to avoid transmitting the lengths for unused bit length codes.
nuclear@2 74 */
nuclear@2 75
nuclear@2 76 #define Buf_size (8 * 2*sizeof(char))
nuclear@2 77 /* Number of bits used within bi_buf. (bi_buf might be implemented on
nuclear@2 78 * more than 16 bits on some systems.)
nuclear@2 79 */
nuclear@2 80
nuclear@2 81 /* ===========================================================================
nuclear@2 82 * Local data. These are initialized only once.
nuclear@2 83 */
nuclear@2 84
nuclear@2 85 #define DIST_CODE_LEN 512 /* see definition of array dist_code below */
nuclear@2 86
nuclear@2 87 #if defined(GEN_TREES_H) || !defined(STDC)
nuclear@2 88 /* non ANSI compilers may not accept trees.h */
nuclear@2 89
nuclear@2 90 local ct_data static_ltree[L_CODES+2];
nuclear@2 91 /* The static literal tree. Since the bit lengths are imposed, there is no
nuclear@2 92 * need for the L_CODES extra codes used during heap construction. However
nuclear@2 93 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
nuclear@2 94 * below).
nuclear@2 95 */
nuclear@2 96
nuclear@2 97 local ct_data static_dtree[D_CODES];
nuclear@2 98 /* The static distance tree. (Actually a trivial tree since all codes use
nuclear@2 99 * 5 bits.)
nuclear@2 100 */
nuclear@2 101
nuclear@2 102 uch _dist_code[DIST_CODE_LEN];
nuclear@2 103 /* Distance codes. The first 256 values correspond to the distances
nuclear@2 104 * 3 .. 258, the last 256 values correspond to the top 8 bits of
nuclear@2 105 * the 15 bit distances.
nuclear@2 106 */
nuclear@2 107
nuclear@2 108 uch _length_code[MAX_MATCH-MIN_MATCH+1];
nuclear@2 109 /* length code for each normalized match length (0 == MIN_MATCH) */
nuclear@2 110
nuclear@2 111 local int base_length[LENGTH_CODES];
nuclear@2 112 /* First normalized length for each code (0 = MIN_MATCH) */
nuclear@2 113
nuclear@2 114 local int base_dist[D_CODES];
nuclear@2 115 /* First normalized distance for each code (0 = distance of 1) */
nuclear@2 116
nuclear@2 117 #else
nuclear@2 118 # include "trees.h"
nuclear@2 119 #endif /* GEN_TREES_H */
nuclear@2 120
nuclear@2 121 struct static_tree_desc_s {
nuclear@2 122 const ct_data *static_tree; /* static tree or NULL */
nuclear@2 123 const intf *extra_bits; /* extra bits for each code or NULL */
nuclear@2 124 int extra_base; /* base index for extra_bits */
nuclear@2 125 int elems; /* max number of elements in the tree */
nuclear@2 126 int max_length; /* max bit length for the codes */
nuclear@2 127 };
nuclear@2 128
nuclear@2 129 local static_tree_desc static_l_desc =
nuclear@2 130 {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
nuclear@2 131
nuclear@2 132 local static_tree_desc static_d_desc =
nuclear@2 133 {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
nuclear@2 134
nuclear@2 135 local static_tree_desc static_bl_desc =
nuclear@2 136 {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
nuclear@2 137
nuclear@2 138 /* ===========================================================================
nuclear@2 139 * Local (static) routines in this file.
nuclear@2 140 */
nuclear@2 141
nuclear@2 142 local void tr_static_init OF((void));
nuclear@2 143 local void init_block OF((deflate_state *s));
nuclear@2 144 local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
nuclear@2 145 local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
nuclear@2 146 local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
nuclear@2 147 local void build_tree OF((deflate_state *s, tree_desc *desc));
nuclear@2 148 local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
nuclear@2 149 local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
nuclear@2 150 local int build_bl_tree OF((deflate_state *s));
nuclear@2 151 local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
nuclear@2 152 int blcodes));
nuclear@2 153 local void compress_block OF((deflate_state *s, ct_data *ltree,
nuclear@2 154 ct_data *dtree));
nuclear@2 155 local void set_data_type OF((deflate_state *s));
nuclear@2 156 local unsigned bi_reverse OF((unsigned value, int length));
nuclear@2 157 local void bi_windup OF((deflate_state *s));
nuclear@2 158 local void bi_flush OF((deflate_state *s));
nuclear@2 159 local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
nuclear@2 160 int header));
nuclear@2 161
nuclear@2 162 #ifdef GEN_TREES_H
nuclear@2 163 local void gen_trees_header OF((void));
nuclear@2 164 #endif
nuclear@2 165
nuclear@2 166 #ifndef DEBUG
nuclear@2 167 # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
nuclear@2 168 /* Send a code of the given tree. c and tree must not have side effects */
nuclear@2 169
nuclear@2 170 #else /* DEBUG */
nuclear@2 171 # define send_code(s, c, tree) \
nuclear@2 172 { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
nuclear@2 173 send_bits(s, tree[c].Code, tree[c].Len); }
nuclear@2 174 #endif
nuclear@2 175
nuclear@2 176 /* ===========================================================================
nuclear@2 177 * Output a short LSB first on the stream.
nuclear@2 178 * IN assertion: there is enough room in pendingBuf.
nuclear@2 179 */
nuclear@2 180 #define put_short(s, w) { \
nuclear@2 181 put_byte(s, (uch)((w) & 0xff)); \
nuclear@2 182 put_byte(s, (uch)((ush)(w) >> 8)); \
nuclear@2 183 }
nuclear@2 184
nuclear@2 185 /* ===========================================================================
nuclear@2 186 * Send a value on a given number of bits.
nuclear@2 187 * IN assertion: length <= 16 and value fits in length bits.
nuclear@2 188 */
nuclear@2 189 #ifdef DEBUG
nuclear@2 190 local void send_bits OF((deflate_state *s, int value, int length));
nuclear@2 191
nuclear@2 192 local void send_bits(s, value, length)
nuclear@2 193 deflate_state *s;
nuclear@2 194 int value; /* value to send */
nuclear@2 195 int length; /* number of bits */
nuclear@2 196 {
nuclear@2 197 Tracevv((stderr," l %2d v %4x ", length, value));
nuclear@2 198 Assert(length > 0 && length <= 15, "invalid length");
nuclear@2 199 s->bits_sent += (ulg)length;
nuclear@2 200
nuclear@2 201 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
nuclear@2 202 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
nuclear@2 203 * unused bits in value.
nuclear@2 204 */
nuclear@2 205 if (s->bi_valid > (int)Buf_size - length) {
nuclear@2 206 s->bi_buf |= (value << s->bi_valid);
nuclear@2 207 put_short(s, s->bi_buf);
nuclear@2 208 s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
nuclear@2 209 s->bi_valid += length - Buf_size;
nuclear@2 210 } else {
nuclear@2 211 s->bi_buf |= value << s->bi_valid;
nuclear@2 212 s->bi_valid += length;
nuclear@2 213 }
nuclear@2 214 }
nuclear@2 215 #else /* !DEBUG */
nuclear@2 216
nuclear@2 217 #define send_bits(s, value, length) \
nuclear@2 218 { int len = length;\
nuclear@2 219 if (s->bi_valid > (int)Buf_size - len) {\
nuclear@2 220 int val = value;\
nuclear@2 221 s->bi_buf |= (val << s->bi_valid);\
nuclear@2 222 put_short(s, s->bi_buf);\
nuclear@2 223 s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
nuclear@2 224 s->bi_valid += len - Buf_size;\
nuclear@2 225 } else {\
nuclear@2 226 s->bi_buf |= (value) << s->bi_valid;\
nuclear@2 227 s->bi_valid += len;\
nuclear@2 228 }\
nuclear@2 229 }
nuclear@2 230 #endif /* DEBUG */
nuclear@2 231
nuclear@2 232
nuclear@2 233 /* the arguments must not have side effects */
nuclear@2 234
nuclear@2 235 /* ===========================================================================
nuclear@2 236 * Initialize the various 'constant' tables.
nuclear@2 237 */
nuclear@2 238 local void tr_static_init()
nuclear@2 239 {
nuclear@2 240 #if defined(GEN_TREES_H) || !defined(STDC)
nuclear@2 241 static int static_init_done = 0;
nuclear@2 242 int n; /* iterates over tree elements */
nuclear@2 243 int bits; /* bit counter */
nuclear@2 244 int length; /* length value */
nuclear@2 245 int code; /* code value */
nuclear@2 246 int dist; /* distance index */
nuclear@2 247 ush bl_count[MAX_BITS+1];
nuclear@2 248 /* number of codes at each bit length for an optimal tree */
nuclear@2 249
nuclear@2 250 if (static_init_done) return;
nuclear@2 251
nuclear@2 252 /* For some embedded targets, global variables are not initialized: */
nuclear@2 253 static_l_desc.static_tree = static_ltree;
nuclear@2 254 static_l_desc.extra_bits = extra_lbits;
nuclear@2 255 static_d_desc.static_tree = static_dtree;
nuclear@2 256 static_d_desc.extra_bits = extra_dbits;
nuclear@2 257 static_bl_desc.extra_bits = extra_blbits;
nuclear@2 258
nuclear@2 259 /* Initialize the mapping length (0..255) -> length code (0..28) */
nuclear@2 260 length = 0;
nuclear@2 261 for (code = 0; code < LENGTH_CODES-1; code++) {
nuclear@2 262 base_length[code] = length;
nuclear@2 263 for (n = 0; n < (1<<extra_lbits[code]); n++) {
nuclear@2 264 _length_code[length++] = (uch)code;
nuclear@2 265 }
nuclear@2 266 }
nuclear@2 267 Assert (length == 256, "tr_static_init: length != 256");
nuclear@2 268 /* Note that the length 255 (match length 258) can be represented
nuclear@2 269 * in two different ways: code 284 + 5 bits or code 285, so we
nuclear@2 270 * overwrite length_code[255] to use the best encoding:
nuclear@2 271 */
nuclear@2 272 _length_code[length-1] = (uch)code;
nuclear@2 273
nuclear@2 274 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
nuclear@2 275 dist = 0;
nuclear@2 276 for (code = 0 ; code < 16; code++) {
nuclear@2 277 base_dist[code] = dist;
nuclear@2 278 for (n = 0; n < (1<<extra_dbits[code]); n++) {
nuclear@2 279 _dist_code[dist++] = (uch)code;
nuclear@2 280 }
nuclear@2 281 }
nuclear@2 282 Assert (dist == 256, "tr_static_init: dist != 256");
nuclear@2 283 dist >>= 7; /* from now on, all distances are divided by 128 */
nuclear@2 284 for ( ; code < D_CODES; code++) {
nuclear@2 285 base_dist[code] = dist << 7;
nuclear@2 286 for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
nuclear@2 287 _dist_code[256 + dist++] = (uch)code;
nuclear@2 288 }
nuclear@2 289 }
nuclear@2 290 Assert (dist == 256, "tr_static_init: 256+dist != 512");
nuclear@2 291
nuclear@2 292 /* Construct the codes of the static literal tree */
nuclear@2 293 for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
nuclear@2 294 n = 0;
nuclear@2 295 while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
nuclear@2 296 while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
nuclear@2 297 while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
nuclear@2 298 while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
nuclear@2 299 /* Codes 286 and 287 do not exist, but we must include them in the
nuclear@2 300 * tree construction to get a canonical Huffman tree (longest code
nuclear@2 301 * all ones)
nuclear@2 302 */
nuclear@2 303 gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
nuclear@2 304
nuclear@2 305 /* The static distance tree is trivial: */
nuclear@2 306 for (n = 0; n < D_CODES; n++) {
nuclear@2 307 static_dtree[n].Len = 5;
nuclear@2 308 static_dtree[n].Code = bi_reverse((unsigned)n, 5);
nuclear@2 309 }
nuclear@2 310 static_init_done = 1;
nuclear@2 311
nuclear@2 312 # ifdef GEN_TREES_H
nuclear@2 313 gen_trees_header();
nuclear@2 314 # endif
nuclear@2 315 #endif /* defined(GEN_TREES_H) || !defined(STDC) */
nuclear@2 316 }
nuclear@2 317
nuclear@2 318 /* ===========================================================================
nuclear@2 319 * Genererate the file trees.h describing the static trees.
nuclear@2 320 */
nuclear@2 321 #ifdef GEN_TREES_H
nuclear@2 322 # ifndef DEBUG
nuclear@2 323 # include <stdio.h>
nuclear@2 324 # endif
nuclear@2 325
nuclear@2 326 # define SEPARATOR(i, last, width) \
nuclear@2 327 ((i) == (last)? "\n};\n\n" : \
nuclear@2 328 ((i) % (width) == (width)-1 ? ",\n" : ", "))
nuclear@2 329
nuclear@2 330 void gen_trees_header()
nuclear@2 331 {
nuclear@2 332 FILE *header = fopen("trees.h", "w");
nuclear@2 333 int i;
nuclear@2 334
nuclear@2 335 Assert (header != NULL, "Can't open trees.h");
nuclear@2 336 fprintf(header,
nuclear@2 337 "/* header created automatically with -DGEN_TREES_H */\n\n");
nuclear@2 338
nuclear@2 339 fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
nuclear@2 340 for (i = 0; i < L_CODES+2; i++) {
nuclear@2 341 fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
nuclear@2 342 static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
nuclear@2 343 }
nuclear@2 344
nuclear@2 345 fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
nuclear@2 346 for (i = 0; i < D_CODES; i++) {
nuclear@2 347 fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
nuclear@2 348 static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
nuclear@2 349 }
nuclear@2 350
nuclear@2 351 fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n");
nuclear@2 352 for (i = 0; i < DIST_CODE_LEN; i++) {
nuclear@2 353 fprintf(header, "%2u%s", _dist_code[i],
nuclear@2 354 SEPARATOR(i, DIST_CODE_LEN-1, 20));
nuclear@2 355 }
nuclear@2 356
nuclear@2 357 fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
nuclear@2 358 for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
nuclear@2 359 fprintf(header, "%2u%s", _length_code[i],
nuclear@2 360 SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
nuclear@2 361 }
nuclear@2 362
nuclear@2 363 fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
nuclear@2 364 for (i = 0; i < LENGTH_CODES; i++) {
nuclear@2 365 fprintf(header, "%1u%s", base_length[i],
nuclear@2 366 SEPARATOR(i, LENGTH_CODES-1, 20));
nuclear@2 367 }
nuclear@2 368
nuclear@2 369 fprintf(header, "local const int base_dist[D_CODES] = {\n");
nuclear@2 370 for (i = 0; i < D_CODES; i++) {
nuclear@2 371 fprintf(header, "%5u%s", base_dist[i],
nuclear@2 372 SEPARATOR(i, D_CODES-1, 10));
nuclear@2 373 }
nuclear@2 374
nuclear@2 375 fclose(header);
nuclear@2 376 }
nuclear@2 377 #endif /* GEN_TREES_H */
nuclear@2 378
nuclear@2 379 /* ===========================================================================
nuclear@2 380 * Initialize the tree data structures for a new zlib stream.
nuclear@2 381 */
nuclear@2 382 void _tr_init(s)
nuclear@2 383 deflate_state *s;
nuclear@2 384 {
nuclear@2 385 tr_static_init();
nuclear@2 386
nuclear@2 387 s->l_desc.dyn_tree = s->dyn_ltree;
nuclear@2 388 s->l_desc.stat_desc = &static_l_desc;
nuclear@2 389
nuclear@2 390 s->d_desc.dyn_tree = s->dyn_dtree;
nuclear@2 391 s->d_desc.stat_desc = &static_d_desc;
nuclear@2 392
nuclear@2 393 s->bl_desc.dyn_tree = s->bl_tree;
nuclear@2 394 s->bl_desc.stat_desc = &static_bl_desc;
nuclear@2 395
nuclear@2 396 s->bi_buf = 0;
nuclear@2 397 s->bi_valid = 0;
nuclear@2 398 s->last_eob_len = 8; /* enough lookahead for inflate */
nuclear@2 399 #ifdef DEBUG
nuclear@2 400 s->compressed_len = 0L;
nuclear@2 401 s->bits_sent = 0L;
nuclear@2 402 #endif
nuclear@2 403
nuclear@2 404 /* Initialize the first block of the first file: */
nuclear@2 405 init_block(s);
nuclear@2 406 }
nuclear@2 407
nuclear@2 408 /* ===========================================================================
nuclear@2 409 * Initialize a new block.
nuclear@2 410 */
nuclear@2 411 local void init_block(s)
nuclear@2 412 deflate_state *s;
nuclear@2 413 {
nuclear@2 414 int n; /* iterates over tree elements */
nuclear@2 415
nuclear@2 416 /* Initialize the trees. */
nuclear@2 417 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
nuclear@2 418 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
nuclear@2 419 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
nuclear@2 420
nuclear@2 421 s->dyn_ltree[END_BLOCK].Freq = 1;
nuclear@2 422 s->opt_len = s->static_len = 0L;
nuclear@2 423 s->last_lit = s->matches = 0;
nuclear@2 424 }
nuclear@2 425
nuclear@2 426 #define SMALLEST 1
nuclear@2 427 /* Index within the heap array of least frequent node in the Huffman tree */
nuclear@2 428
nuclear@2 429
nuclear@2 430 /* ===========================================================================
nuclear@2 431 * Remove the smallest element from the heap and recreate the heap with
nuclear@2 432 * one less element. Updates heap and heap_len.
nuclear@2 433 */
nuclear@2 434 #define pqremove(s, tree, top) \
nuclear@2 435 {\
nuclear@2 436 top = s->heap[SMALLEST]; \
nuclear@2 437 s->heap[SMALLEST] = s->heap[s->heap_len--]; \
nuclear@2 438 pqdownheap(s, tree, SMALLEST); \
nuclear@2 439 }
nuclear@2 440
nuclear@2 441 /* ===========================================================================
nuclear@2 442 * Compares to subtrees, using the tree depth as tie breaker when
nuclear@2 443 * the subtrees have equal frequency. This minimizes the worst case length.
nuclear@2 444 */
nuclear@2 445 #define smaller(tree, n, m, depth) \
nuclear@2 446 (tree[n].Freq < tree[m].Freq || \
nuclear@2 447 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
nuclear@2 448
nuclear@2 449 /* ===========================================================================
nuclear@2 450 * Restore the heap property by moving down the tree starting at node k,
nuclear@2 451 * exchanging a node with the smallest of its two sons if necessary, stopping
nuclear@2 452 * when the heap property is re-established (each father smaller than its
nuclear@2 453 * two sons).
nuclear@2 454 */
nuclear@2 455 local void pqdownheap(s, tree, k)
nuclear@2 456 deflate_state *s;
nuclear@2 457 ct_data *tree; /* the tree to restore */
nuclear@2 458 int k; /* node to move down */
nuclear@2 459 {
nuclear@2 460 int v = s->heap[k];
nuclear@2 461 int j = k << 1; /* left son of k */
nuclear@2 462 while (j <= s->heap_len) {
nuclear@2 463 /* Set j to the smallest of the two sons: */
nuclear@2 464 if (j < s->heap_len &&
nuclear@2 465 smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
nuclear@2 466 j++;
nuclear@2 467 }
nuclear@2 468 /* Exit if v is smaller than both sons */
nuclear@2 469 if (smaller(tree, v, s->heap[j], s->depth)) break;
nuclear@2 470
nuclear@2 471 /* Exchange v with the smallest son */
nuclear@2 472 s->heap[k] = s->heap[j]; k = j;
nuclear@2 473
nuclear@2 474 /* And continue down the tree, setting j to the left son of k */
nuclear@2 475 j <<= 1;
nuclear@2 476 }
nuclear@2 477 s->heap[k] = v;
nuclear@2 478 }
nuclear@2 479
nuclear@2 480 /* ===========================================================================
nuclear@2 481 * Compute the optimal bit lengths for a tree and update the total bit length
nuclear@2 482 * for the current block.
nuclear@2 483 * IN assertion: the fields freq and dad are set, heap[heap_max] and
nuclear@2 484 * above are the tree nodes sorted by increasing frequency.
nuclear@2 485 * OUT assertions: the field len is set to the optimal bit length, the
nuclear@2 486 * array bl_count contains the frequencies for each bit length.
nuclear@2 487 * The length opt_len is updated; static_len is also updated if stree is
nuclear@2 488 * not null.
nuclear@2 489 */
nuclear@2 490 local void gen_bitlen(s, desc)
nuclear@2 491 deflate_state *s;
nuclear@2 492 tree_desc *desc; /* the tree descriptor */
nuclear@2 493 {
nuclear@2 494 ct_data *tree = desc->dyn_tree;
nuclear@2 495 int max_code = desc->max_code;
nuclear@2 496 const ct_data *stree = desc->stat_desc->static_tree;
nuclear@2 497 const intf *extra = desc->stat_desc->extra_bits;
nuclear@2 498 int base = desc->stat_desc->extra_base;
nuclear@2 499 int max_length = desc->stat_desc->max_length;
nuclear@2 500 int h; /* heap index */
nuclear@2 501 int n, m; /* iterate over the tree elements */
nuclear@2 502 int bits; /* bit length */
nuclear@2 503 int xbits; /* extra bits */
nuclear@2 504 ush f; /* frequency */
nuclear@2 505 int overflow = 0; /* number of elements with bit length too large */
nuclear@2 506
nuclear@2 507 for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
nuclear@2 508
nuclear@2 509 /* In a first pass, compute the optimal bit lengths (which may
nuclear@2 510 * overflow in the case of the bit length tree).
nuclear@2 511 */
nuclear@2 512 tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
nuclear@2 513
nuclear@2 514 for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
nuclear@2 515 n = s->heap[h];
nuclear@2 516 bits = tree[tree[n].Dad].Len + 1;
nuclear@2 517 if (bits > max_length) bits = max_length, overflow++;
nuclear@2 518 tree[n].Len = (ush)bits;
nuclear@2 519 /* We overwrite tree[n].Dad which is no longer needed */
nuclear@2 520
nuclear@2 521 if (n > max_code) continue; /* not a leaf node */
nuclear@2 522
nuclear@2 523 s->bl_count[bits]++;
nuclear@2 524 xbits = 0;
nuclear@2 525 if (n >= base) xbits = extra[n-base];
nuclear@2 526 f = tree[n].Freq;
nuclear@2 527 s->opt_len += (ulg)f * (bits + xbits);
nuclear@2 528 if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
nuclear@2 529 }
nuclear@2 530 if (overflow == 0) return;
nuclear@2 531
nuclear@2 532 Trace((stderr,"\nbit length overflow\n"));
nuclear@2 533 /* This happens for example on obj2 and pic of the Calgary corpus */
nuclear@2 534
nuclear@2 535 /* Find the first bit length which could increase: */
nuclear@2 536 do {
nuclear@2 537 bits = max_length-1;
nuclear@2 538 while (s->bl_count[bits] == 0) bits--;
nuclear@2 539 s->bl_count[bits]--; /* move one leaf down the tree */
nuclear@2 540 s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
nuclear@2 541 s->bl_count[max_length]--;
nuclear@2 542 /* The brother of the overflow item also moves one step up,
nuclear@2 543 * but this does not affect bl_count[max_length]
nuclear@2 544 */
nuclear@2 545 overflow -= 2;
nuclear@2 546 } while (overflow > 0);
nuclear@2 547
nuclear@2 548 /* Now recompute all bit lengths, scanning in increasing frequency.
nuclear@2 549 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
nuclear@2 550 * lengths instead of fixing only the wrong ones. This idea is taken
nuclear@2 551 * from 'ar' written by Haruhiko Okumura.)
nuclear@2 552 */
nuclear@2 553 for (bits = max_length; bits != 0; bits--) {
nuclear@2 554 n = s->bl_count[bits];
nuclear@2 555 while (n != 0) {
nuclear@2 556 m = s->heap[--h];
nuclear@2 557 if (m > max_code) continue;
nuclear@2 558 if ((unsigned) tree[m].Len != (unsigned) bits) {
nuclear@2 559 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
nuclear@2 560 s->opt_len += ((long)bits - (long)tree[m].Len)
nuclear@2 561 *(long)tree[m].Freq;
nuclear@2 562 tree[m].Len = (ush)bits;
nuclear@2 563 }
nuclear@2 564 n--;
nuclear@2 565 }
nuclear@2 566 }
nuclear@2 567 }
nuclear@2 568
nuclear@2 569 /* ===========================================================================
nuclear@2 570 * Generate the codes for a given tree and bit counts (which need not be
nuclear@2 571 * optimal).
nuclear@2 572 * IN assertion: the array bl_count contains the bit length statistics for
nuclear@2 573 * the given tree and the field len is set for all tree elements.
nuclear@2 574 * OUT assertion: the field code is set for all tree elements of non
nuclear@2 575 * zero code length.
nuclear@2 576 */
nuclear@2 577 local void gen_codes (tree, max_code, bl_count)
nuclear@2 578 ct_data *tree; /* the tree to decorate */
nuclear@2 579 int max_code; /* largest code with non zero frequency */
nuclear@2 580 ushf *bl_count; /* number of codes at each bit length */
nuclear@2 581 {
nuclear@2 582 ush next_code[MAX_BITS+1]; /* next code value for each bit length */
nuclear@2 583 ush code = 0; /* running code value */
nuclear@2 584 int bits; /* bit index */
nuclear@2 585 int n; /* code index */
nuclear@2 586
nuclear@2 587 /* The distribution counts are first used to generate the code values
nuclear@2 588 * without bit reversal.
nuclear@2 589 */
nuclear@2 590 for (bits = 1; bits <= MAX_BITS; bits++) {
nuclear@2 591 next_code[bits] = code = (code + bl_count[bits-1]) << 1;
nuclear@2 592 }
nuclear@2 593 /* Check that the bit counts in bl_count are consistent. The last code
nuclear@2 594 * must be all ones.
nuclear@2 595 */
nuclear@2 596 Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
nuclear@2 597 "inconsistent bit counts");
nuclear@2 598 Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
nuclear@2 599
nuclear@2 600 for (n = 0; n <= max_code; n++) {
nuclear@2 601 int len = tree[n].Len;
nuclear@2 602 if (len == 0) continue;
nuclear@2 603 /* Now reverse the bits */
nuclear@2 604 tree[n].Code = bi_reverse(next_code[len]++, len);
nuclear@2 605
nuclear@2 606 Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
nuclear@2 607 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
nuclear@2 608 }
nuclear@2 609 }
nuclear@2 610
nuclear@2 611 /* ===========================================================================
nuclear@2 612 * Construct one Huffman tree and assigns the code bit strings and lengths.
nuclear@2 613 * Update the total bit length for the current block.
nuclear@2 614 * IN assertion: the field freq is set for all tree elements.
nuclear@2 615 * OUT assertions: the fields len and code are set to the optimal bit length
nuclear@2 616 * and corresponding code. The length opt_len is updated; static_len is
nuclear@2 617 * also updated if stree is not null. The field max_code is set.
nuclear@2 618 */
nuclear@2 619 local void build_tree(s, desc)
nuclear@2 620 deflate_state *s;
nuclear@2 621 tree_desc *desc; /* the tree descriptor */
nuclear@2 622 {
nuclear@2 623 ct_data *tree = desc->dyn_tree;
nuclear@2 624 const ct_data *stree = desc->stat_desc->static_tree;
nuclear@2 625 int elems = desc->stat_desc->elems;
nuclear@2 626 int n, m; /* iterate over heap elements */
nuclear@2 627 int max_code = -1; /* largest code with non zero frequency */
nuclear@2 628 int node; /* new node being created */
nuclear@2 629
nuclear@2 630 /* Construct the initial heap, with least frequent element in
nuclear@2 631 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
nuclear@2 632 * heap[0] is not used.
nuclear@2 633 */
nuclear@2 634 s->heap_len = 0, s->heap_max = HEAP_SIZE;
nuclear@2 635
nuclear@2 636 for (n = 0; n < elems; n++) {
nuclear@2 637 if (tree[n].Freq != 0) {
nuclear@2 638 s->heap[++(s->heap_len)] = max_code = n;
nuclear@2 639 s->depth[n] = 0;
nuclear@2 640 } else {
nuclear@2 641 tree[n].Len = 0;
nuclear@2 642 }
nuclear@2 643 }
nuclear@2 644
nuclear@2 645 /* The pkzip format requires that at least one distance code exists,
nuclear@2 646 * and that at least one bit should be sent even if there is only one
nuclear@2 647 * possible code. So to avoid special checks later on we force at least
nuclear@2 648 * two codes of non zero frequency.
nuclear@2 649 */
nuclear@2 650 while (s->heap_len < 2) {
nuclear@2 651 node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
nuclear@2 652 tree[node].Freq = 1;
nuclear@2 653 s->depth[node] = 0;
nuclear@2 654 s->opt_len--; if (stree) s->static_len -= stree[node].Len;
nuclear@2 655 /* node is 0 or 1 so it does not have extra bits */
nuclear@2 656 }
nuclear@2 657 desc->max_code = max_code;
nuclear@2 658
nuclear@2 659 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
nuclear@2 660 * establish sub-heaps of increasing lengths:
nuclear@2 661 */
nuclear@2 662 for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
nuclear@2 663
nuclear@2 664 /* Construct the Huffman tree by repeatedly combining the least two
nuclear@2 665 * frequent nodes.
nuclear@2 666 */
nuclear@2 667 node = elems; /* next internal node of the tree */
nuclear@2 668 do {
nuclear@2 669 pqremove(s, tree, n); /* n = node of least frequency */
nuclear@2 670 m = s->heap[SMALLEST]; /* m = node of next least frequency */
nuclear@2 671
nuclear@2 672 s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
nuclear@2 673 s->heap[--(s->heap_max)] = m;
nuclear@2 674
nuclear@2 675 /* Create a new node father of n and m */
nuclear@2 676 tree[node].Freq = tree[n].Freq + tree[m].Freq;
nuclear@2 677 s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
nuclear@2 678 s->depth[n] : s->depth[m]) + 1);
nuclear@2 679 tree[n].Dad = tree[m].Dad = (ush)node;
nuclear@2 680 #ifdef DUMP_BL_TREE
nuclear@2 681 if (tree == s->bl_tree) {
nuclear@2 682 fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
nuclear@2 683 node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
nuclear@2 684 }
nuclear@2 685 #endif
nuclear@2 686 /* and insert the new node in the heap */
nuclear@2 687 s->heap[SMALLEST] = node++;
nuclear@2 688 pqdownheap(s, tree, SMALLEST);
nuclear@2 689
nuclear@2 690 } while (s->heap_len >= 2);
nuclear@2 691
nuclear@2 692 s->heap[--(s->heap_max)] = s->heap[SMALLEST];
nuclear@2 693
nuclear@2 694 /* At this point, the fields freq and dad are set. We can now
nuclear@2 695 * generate the bit lengths.
nuclear@2 696 */
nuclear@2 697 gen_bitlen(s, (tree_desc *)desc);
nuclear@2 698
nuclear@2 699 /* The field len is now set, we can generate the bit codes */
nuclear@2 700 gen_codes ((ct_data *)tree, max_code, s->bl_count);
nuclear@2 701 }
nuclear@2 702
nuclear@2 703 /* ===========================================================================
nuclear@2 704 * Scan a literal or distance tree to determine the frequencies of the codes
nuclear@2 705 * in the bit length tree.
nuclear@2 706 */
nuclear@2 707 local void scan_tree (s, tree, max_code)
nuclear@2 708 deflate_state *s;
nuclear@2 709 ct_data *tree; /* the tree to be scanned */
nuclear@2 710 int max_code; /* and its largest code of non zero frequency */
nuclear@2 711 {
nuclear@2 712 int n; /* iterates over all tree elements */
nuclear@2 713 int prevlen = -1; /* last emitted length */
nuclear@2 714 int curlen; /* length of current code */
nuclear@2 715 int nextlen = tree[0].Len; /* length of next code */
nuclear@2 716 int count = 0; /* repeat count of the current code */
nuclear@2 717 int max_count = 7; /* max repeat count */
nuclear@2 718 int min_count = 4; /* min repeat count */
nuclear@2 719
nuclear@2 720 if (nextlen == 0) max_count = 138, min_count = 3;
nuclear@2 721 tree[max_code+1].Len = (ush)0xffff; /* guard */
nuclear@2 722
nuclear@2 723 for (n = 0; n <= max_code; n++) {
nuclear@2 724 curlen = nextlen; nextlen = tree[n+1].Len;
nuclear@2 725 if (++count < max_count && curlen == nextlen) {
nuclear@2 726 continue;
nuclear@2 727 } else if (count < min_count) {
nuclear@2 728 s->bl_tree[curlen].Freq += count;
nuclear@2 729 } else if (curlen != 0) {
nuclear@2 730 if (curlen != prevlen) s->bl_tree[curlen].Freq++;
nuclear@2 731 s->bl_tree[REP_3_6].Freq++;
nuclear@2 732 } else if (count <= 10) {
nuclear@2 733 s->bl_tree[REPZ_3_10].Freq++;
nuclear@2 734 } else {
nuclear@2 735 s->bl_tree[REPZ_11_138].Freq++;
nuclear@2 736 }
nuclear@2 737 count = 0; prevlen = curlen;
nuclear@2 738 if (nextlen == 0) {
nuclear@2 739 max_count = 138, min_count = 3;
nuclear@2 740 } else if (curlen == nextlen) {
nuclear@2 741 max_count = 6, min_count = 3;
nuclear@2 742 } else {
nuclear@2 743 max_count = 7, min_count = 4;
nuclear@2 744 }
nuclear@2 745 }
nuclear@2 746 }
nuclear@2 747
nuclear@2 748 /* ===========================================================================
nuclear@2 749 * Send a literal or distance tree in compressed form, using the codes in
nuclear@2 750 * bl_tree.
nuclear@2 751 */
nuclear@2 752 local void send_tree (s, tree, max_code)
nuclear@2 753 deflate_state *s;
nuclear@2 754 ct_data *tree; /* the tree to be scanned */
nuclear@2 755 int max_code; /* and its largest code of non zero frequency */
nuclear@2 756 {
nuclear@2 757 int n; /* iterates over all tree elements */
nuclear@2 758 int prevlen = -1; /* last emitted length */
nuclear@2 759 int curlen; /* length of current code */
nuclear@2 760 int nextlen = tree[0].Len; /* length of next code */
nuclear@2 761 int count = 0; /* repeat count of the current code */
nuclear@2 762 int max_count = 7; /* max repeat count */
nuclear@2 763 int min_count = 4; /* min repeat count */
nuclear@2 764
nuclear@2 765 /* tree[max_code+1].Len = -1; */ /* guard already set */
nuclear@2 766 if (nextlen == 0) max_count = 138, min_count = 3;
nuclear@2 767
nuclear@2 768 for (n = 0; n <= max_code; n++) {
nuclear@2 769 curlen = nextlen; nextlen = tree[n+1].Len;
nuclear@2 770 if (++count < max_count && curlen == nextlen) {
nuclear@2 771 continue;
nuclear@2 772 } else if (count < min_count) {
nuclear@2 773 do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
nuclear@2 774
nuclear@2 775 } else if (curlen != 0) {
nuclear@2 776 if (curlen != prevlen) {
nuclear@2 777 send_code(s, curlen, s->bl_tree); count--;
nuclear@2 778 }
nuclear@2 779 Assert(count >= 3 && count <= 6, " 3_6?");
nuclear@2 780 send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
nuclear@2 781
nuclear@2 782 } else if (count <= 10) {
nuclear@2 783 send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
nuclear@2 784
nuclear@2 785 } else {
nuclear@2 786 send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
nuclear@2 787 }
nuclear@2 788 count = 0; prevlen = curlen;
nuclear@2 789 if (nextlen == 0) {
nuclear@2 790 max_count = 138, min_count = 3;
nuclear@2 791 } else if (curlen == nextlen) {
nuclear@2 792 max_count = 6, min_count = 3;
nuclear@2 793 } else {
nuclear@2 794 max_count = 7, min_count = 4;
nuclear@2 795 }
nuclear@2 796 }
nuclear@2 797 }
nuclear@2 798
nuclear@2 799 /* ===========================================================================
nuclear@2 800 * Construct the Huffman tree for the bit lengths and return the index in
nuclear@2 801 * bl_order of the last bit length code to send.
nuclear@2 802 */
nuclear@2 803 local int build_bl_tree(s)
nuclear@2 804 deflate_state *s;
nuclear@2 805 {
nuclear@2 806 int max_blindex; /* index of last bit length code of non zero freq */
nuclear@2 807
nuclear@2 808 /* Determine the bit length frequencies for literal and distance trees */
nuclear@2 809 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
nuclear@2 810 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
nuclear@2 811
nuclear@2 812 /* Build the bit length tree: */
nuclear@2 813 build_tree(s, (tree_desc *)(&(s->bl_desc)));
nuclear@2 814 /* opt_len now includes the length of the tree representations, except
nuclear@2 815 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
nuclear@2 816 */
nuclear@2 817
nuclear@2 818 /* Determine the number of bit length codes to send. The pkzip format
nuclear@2 819 * requires that at least 4 bit length codes be sent. (appnote.txt says
nuclear@2 820 * 3 but the actual value used is 4.)
nuclear@2 821 */
nuclear@2 822 for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
nuclear@2 823 if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
nuclear@2 824 }
nuclear@2 825 /* Update opt_len to include the bit length tree and counts */
nuclear@2 826 s->opt_len += 3*(max_blindex+1) + 5+5+4;
nuclear@2 827 Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
nuclear@2 828 s->opt_len, s->static_len));
nuclear@2 829
nuclear@2 830 return max_blindex;
nuclear@2 831 }
nuclear@2 832
nuclear@2 833 /* ===========================================================================
nuclear@2 834 * Send the header for a block using dynamic Huffman trees: the counts, the
nuclear@2 835 * lengths of the bit length codes, the literal tree and the distance tree.
nuclear@2 836 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
nuclear@2 837 */
nuclear@2 838 local void send_all_trees(s, lcodes, dcodes, blcodes)
nuclear@2 839 deflate_state *s;
nuclear@2 840 int lcodes, dcodes, blcodes; /* number of codes for each tree */
nuclear@2 841 {
nuclear@2 842 int rank; /* index in bl_order */
nuclear@2 843
nuclear@2 844 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
nuclear@2 845 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
nuclear@2 846 "too many codes");
nuclear@2 847 Tracev((stderr, "\nbl counts: "));
nuclear@2 848 send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
nuclear@2 849 send_bits(s, dcodes-1, 5);
nuclear@2 850 send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
nuclear@2 851 for (rank = 0; rank < blcodes; rank++) {
nuclear@2 852 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
nuclear@2 853 send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
nuclear@2 854 }
nuclear@2 855 Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
nuclear@2 856
nuclear@2 857 send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
nuclear@2 858 Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
nuclear@2 859
nuclear@2 860 send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
nuclear@2 861 Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
nuclear@2 862 }
nuclear@2 863
nuclear@2 864 /* ===========================================================================
nuclear@2 865 * Send a stored block
nuclear@2 866 */
nuclear@2 867 void _tr_stored_block(s, buf, stored_len, eof)
nuclear@2 868 deflate_state *s;
nuclear@2 869 charf *buf; /* input block */
nuclear@2 870 ulg stored_len; /* length of input block */
nuclear@2 871 int eof; /* true if this is the last block for a file */
nuclear@2 872 {
nuclear@2 873 send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */
nuclear@2 874 #ifdef DEBUG
nuclear@2 875 s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
nuclear@2 876 s->compressed_len += (stored_len + 4) << 3;
nuclear@2 877 #endif
nuclear@2 878 copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
nuclear@2 879 }
nuclear@2 880
nuclear@2 881 /* ===========================================================================
nuclear@2 882 * Send one empty static block to give enough lookahead for inflate.
nuclear@2 883 * This takes 10 bits, of which 7 may remain in the bit buffer.
nuclear@2 884 * The current inflate code requires 9 bits of lookahead. If the
nuclear@2 885 * last two codes for the previous block (real code plus EOB) were coded
nuclear@2 886 * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
nuclear@2 887 * the last real code. In this case we send two empty static blocks instead
nuclear@2 888 * of one. (There are no problems if the previous block is stored or fixed.)
nuclear@2 889 * To simplify the code, we assume the worst case of last real code encoded
nuclear@2 890 * on one bit only.
nuclear@2 891 */
nuclear@2 892 void _tr_align(s)
nuclear@2 893 deflate_state *s;
nuclear@2 894 {
nuclear@2 895 send_bits(s, STATIC_TREES<<1, 3);
nuclear@2 896 send_code(s, END_BLOCK, static_ltree);
nuclear@2 897 #ifdef DEBUG
nuclear@2 898 s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
nuclear@2 899 #endif
nuclear@2 900 bi_flush(s);
nuclear@2 901 /* Of the 10 bits for the empty block, we have already sent
nuclear@2 902 * (10 - bi_valid) bits. The lookahead for the last real code (before
nuclear@2 903 * the EOB of the previous block) was thus at least one plus the length
nuclear@2 904 * of the EOB plus what we have just sent of the empty static block.
nuclear@2 905 */
nuclear@2 906 if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
nuclear@2 907 send_bits(s, STATIC_TREES<<1, 3);
nuclear@2 908 send_code(s, END_BLOCK, static_ltree);
nuclear@2 909 #ifdef DEBUG
nuclear@2 910 s->compressed_len += 10L;
nuclear@2 911 #endif
nuclear@2 912 bi_flush(s);
nuclear@2 913 }
nuclear@2 914 s->last_eob_len = 7;
nuclear@2 915 }
nuclear@2 916
nuclear@2 917 /* ===========================================================================
nuclear@2 918 * Determine the best encoding for the current block: dynamic trees, static
nuclear@2 919 * trees or store, and output the encoded block to the zip file.
nuclear@2 920 */
nuclear@2 921 void _tr_flush_block(s, buf, stored_len, eof)
nuclear@2 922 deflate_state *s;
nuclear@2 923 charf *buf; /* input block, or NULL if too old */
nuclear@2 924 ulg stored_len; /* length of input block */
nuclear@2 925 int eof; /* true if this is the last block for a file */
nuclear@2 926 {
nuclear@2 927 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
nuclear@2 928 int max_blindex = 0; /* index of last bit length code of non zero freq */
nuclear@2 929
nuclear@2 930 /* Build the Huffman trees unless a stored block is forced */
nuclear@2 931 if (s->level > 0) {
nuclear@2 932
nuclear@2 933 /* Check if the file is binary or text */
nuclear@2 934 if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN)
nuclear@2 935 set_data_type(s);
nuclear@2 936
nuclear@2 937 /* Construct the literal and distance trees */
nuclear@2 938 build_tree(s, (tree_desc *)(&(s->l_desc)));
nuclear@2 939 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
nuclear@2 940 s->static_len));
nuclear@2 941
nuclear@2 942 build_tree(s, (tree_desc *)(&(s->d_desc)));
nuclear@2 943 Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
nuclear@2 944 s->static_len));
nuclear@2 945 /* At this point, opt_len and static_len are the total bit lengths of
nuclear@2 946 * the compressed block data, excluding the tree representations.
nuclear@2 947 */
nuclear@2 948
nuclear@2 949 /* Build the bit length tree for the above two trees, and get the index
nuclear@2 950 * in bl_order of the last bit length code to send.
nuclear@2 951 */
nuclear@2 952 max_blindex = build_bl_tree(s);
nuclear@2 953
nuclear@2 954 /* Determine the best encoding. Compute the block lengths in bytes. */
nuclear@2 955 opt_lenb = (s->opt_len+3+7)>>3;
nuclear@2 956 static_lenb = (s->static_len+3+7)>>3;
nuclear@2 957
nuclear@2 958 Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
nuclear@2 959 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
nuclear@2 960 s->last_lit));
nuclear@2 961
nuclear@2 962 if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
nuclear@2 963
nuclear@2 964 } else {
nuclear@2 965 Assert(buf != (char*)0, "lost buf");
nuclear@2 966 opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
nuclear@2 967 }
nuclear@2 968
nuclear@2 969 #ifdef FORCE_STORED
nuclear@2 970 if (buf != (char*)0) { /* force stored block */
nuclear@2 971 #else
nuclear@2 972 if (stored_len+4 <= opt_lenb && buf != (char*)0) {
nuclear@2 973 /* 4: two words for the lengths */
nuclear@2 974 #endif
nuclear@2 975 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
nuclear@2 976 * Otherwise we can't have processed more than WSIZE input bytes since
nuclear@2 977 * the last block flush, because compression would have been
nuclear@2 978 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
nuclear@2 979 * transform a block into a stored block.
nuclear@2 980 */
nuclear@2 981 _tr_stored_block(s, buf, stored_len, eof);
nuclear@2 982
nuclear@2 983 #ifdef FORCE_STATIC
nuclear@2 984 } else if (static_lenb >= 0) { /* force static trees */
nuclear@2 985 #else
nuclear@2 986 } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
nuclear@2 987 #endif
nuclear@2 988 send_bits(s, (STATIC_TREES<<1)+eof, 3);
nuclear@2 989 compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
nuclear@2 990 #ifdef DEBUG
nuclear@2 991 s->compressed_len += 3 + s->static_len;
nuclear@2 992 #endif
nuclear@2 993 } else {
nuclear@2 994 send_bits(s, (DYN_TREES<<1)+eof, 3);
nuclear@2 995 send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
nuclear@2 996 max_blindex+1);
nuclear@2 997 compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
nuclear@2 998 #ifdef DEBUG
nuclear@2 999 s->compressed_len += 3 + s->opt_len;
nuclear@2 1000 #endif
nuclear@2 1001 }
nuclear@2 1002 Assert (s->compressed_len == s->bits_sent, "bad compressed size");
nuclear@2 1003 /* The above check is made mod 2^32, for files larger than 512 MB
nuclear@2 1004 * and uLong implemented on 32 bits.
nuclear@2 1005 */
nuclear@2 1006 init_block(s);
nuclear@2 1007
nuclear@2 1008 if (eof) {
nuclear@2 1009 bi_windup(s);
nuclear@2 1010 #ifdef DEBUG
nuclear@2 1011 s->compressed_len += 7; /* align on byte boundary */
nuclear@2 1012 #endif
nuclear@2 1013 }
nuclear@2 1014 Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
nuclear@2 1015 s->compressed_len-7*eof));
nuclear@2 1016 }
nuclear@2 1017
nuclear@2 1018 /* ===========================================================================
nuclear@2 1019 * Save the match info and tally the frequency counts. Return true if
nuclear@2 1020 * the current block must be flushed.
nuclear@2 1021 */
nuclear@2 1022 int _tr_tally (s, dist, lc)
nuclear@2 1023 deflate_state *s;
nuclear@2 1024 unsigned dist; /* distance of matched string */
nuclear@2 1025 unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
nuclear@2 1026 {
nuclear@2 1027 s->d_buf[s->last_lit] = (ush)dist;
nuclear@2 1028 s->l_buf[s->last_lit++] = (uch)lc;
nuclear@2 1029 if (dist == 0) {
nuclear@2 1030 /* lc is the unmatched char */
nuclear@2 1031 s->dyn_ltree[lc].Freq++;
nuclear@2 1032 } else {
nuclear@2 1033 s->matches++;
nuclear@2 1034 /* Here, lc is the match length - MIN_MATCH */
nuclear@2 1035 dist--; /* dist = match distance - 1 */
nuclear@2 1036 Assert((ush)dist < (ush)MAX_DIST(s) &&
nuclear@2 1037 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
nuclear@2 1038 (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
nuclear@2 1039
nuclear@2 1040 s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
nuclear@2 1041 s->dyn_dtree[d_code(dist)].Freq++;
nuclear@2 1042 }
nuclear@2 1043
nuclear@2 1044 #ifdef TRUNCATE_BLOCK
nuclear@2 1045 /* Try to guess if it is profitable to stop the current block here */
nuclear@2 1046 if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
nuclear@2 1047 /* Compute an upper bound for the compressed length */
nuclear@2 1048 ulg out_length = (ulg)s->last_lit*8L;
nuclear@2 1049 ulg in_length = (ulg)((long)s->strstart - s->block_start);
nuclear@2 1050 int dcode;
nuclear@2 1051 for (dcode = 0; dcode < D_CODES; dcode++) {
nuclear@2 1052 out_length += (ulg)s->dyn_dtree[dcode].Freq *
nuclear@2 1053 (5L+extra_dbits[dcode]);
nuclear@2 1054 }
nuclear@2 1055 out_length >>= 3;
nuclear@2 1056 Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
nuclear@2 1057 s->last_lit, in_length, out_length,
nuclear@2 1058 100L - out_length*100L/in_length));
nuclear@2 1059 if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
nuclear@2 1060 }
nuclear@2 1061 #endif
nuclear@2 1062 return (s->last_lit == s->lit_bufsize-1);
nuclear@2 1063 /* We avoid equality with lit_bufsize because of wraparound at 64K
nuclear@2 1064 * on 16 bit machines and because stored blocks are restricted to
nuclear@2 1065 * 64K-1 bytes.
nuclear@2 1066 */
nuclear@2 1067 }
nuclear@2 1068
nuclear@2 1069 /* ===========================================================================
nuclear@2 1070 * Send the block data compressed using the given Huffman trees
nuclear@2 1071 */
nuclear@2 1072 local void compress_block(s, ltree, dtree)
nuclear@2 1073 deflate_state *s;
nuclear@2 1074 ct_data *ltree; /* literal tree */
nuclear@2 1075 ct_data *dtree; /* distance tree */
nuclear@2 1076 {
nuclear@2 1077 unsigned dist; /* distance of matched string */
nuclear@2 1078 int lc; /* match length or unmatched char (if dist == 0) */
nuclear@2 1079 unsigned lx = 0; /* running index in l_buf */
nuclear@2 1080 unsigned code; /* the code to send */
nuclear@2 1081 int extra; /* number of extra bits to send */
nuclear@2 1082
nuclear@2 1083 if (s->last_lit != 0) do {
nuclear@2 1084 dist = s->d_buf[lx];
nuclear@2 1085 lc = s->l_buf[lx++];
nuclear@2 1086 if (dist == 0) {
nuclear@2 1087 send_code(s, lc, ltree); /* send a literal byte */
nuclear@2 1088 Tracecv(isgraph(lc), (stderr," '%c' ", lc));
nuclear@2 1089 } else {
nuclear@2 1090 /* Here, lc is the match length - MIN_MATCH */
nuclear@2 1091 code = _length_code[lc];
nuclear@2 1092 send_code(s, code+LITERALS+1, ltree); /* send the length code */
nuclear@2 1093 extra = extra_lbits[code];
nuclear@2 1094 if (extra != 0) {
nuclear@2 1095 lc -= base_length[code];
nuclear@2 1096 send_bits(s, lc, extra); /* send the extra length bits */
nuclear@2 1097 }
nuclear@2 1098 dist--; /* dist is now the match distance - 1 */
nuclear@2 1099 code = d_code(dist);
nuclear@2 1100 Assert (code < D_CODES, "bad d_code");
nuclear@2 1101
nuclear@2 1102 send_code(s, code, dtree); /* send the distance code */
nuclear@2 1103 extra = extra_dbits[code];
nuclear@2 1104 if (extra != 0) {
nuclear@2 1105 dist -= base_dist[code];
nuclear@2 1106 send_bits(s, dist, extra); /* send the extra distance bits */
nuclear@2 1107 }
nuclear@2 1108 } /* literal or match pair ? */
nuclear@2 1109
nuclear@2 1110 /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
nuclear@2 1111 Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
nuclear@2 1112 "pendingBuf overflow");
nuclear@2 1113
nuclear@2 1114 } while (lx < s->last_lit);
nuclear@2 1115
nuclear@2 1116 send_code(s, END_BLOCK, ltree);
nuclear@2 1117 s->last_eob_len = ltree[END_BLOCK].Len;
nuclear@2 1118 }
nuclear@2 1119
nuclear@2 1120 /* ===========================================================================
nuclear@2 1121 * Set the data type to BINARY or TEXT, using a crude approximation:
nuclear@2 1122 * set it to Z_TEXT if all symbols are either printable characters (33 to 255)
nuclear@2 1123 * or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise.
nuclear@2 1124 * IN assertion: the fields Freq of dyn_ltree are set.
nuclear@2 1125 */
nuclear@2 1126 local void set_data_type(s)
nuclear@2 1127 deflate_state *s;
nuclear@2 1128 {
nuclear@2 1129 int n;
nuclear@2 1130
nuclear@2 1131 for (n = 0; n < 9; n++)
nuclear@2 1132 if (s->dyn_ltree[n].Freq != 0)
nuclear@2 1133 break;
nuclear@2 1134 if (n == 9)
nuclear@2 1135 for (n = 14; n < 32; n++)
nuclear@2 1136 if (s->dyn_ltree[n].Freq != 0)
nuclear@2 1137 break;
nuclear@2 1138 s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY;
nuclear@2 1139 }
nuclear@2 1140
nuclear@2 1141 /* ===========================================================================
nuclear@2 1142 * Reverse the first len bits of a code, using straightforward code (a faster
nuclear@2 1143 * method would use a table)
nuclear@2 1144 * IN assertion: 1 <= len <= 15
nuclear@2 1145 */
nuclear@2 1146 local unsigned bi_reverse(code, len)
nuclear@2 1147 unsigned code; /* the value to invert */
nuclear@2 1148 int len; /* its bit length */
nuclear@2 1149 {
nuclear@2 1150 register unsigned res = 0;
nuclear@2 1151 do {
nuclear@2 1152 res |= code & 1;
nuclear@2 1153 code >>= 1, res <<= 1;
nuclear@2 1154 } while (--len > 0);
nuclear@2 1155 return res >> 1;
nuclear@2 1156 }
nuclear@2 1157
nuclear@2 1158 /* ===========================================================================
nuclear@2 1159 * Flush the bit buffer, keeping at most 7 bits in it.
nuclear@2 1160 */
nuclear@2 1161 local void bi_flush(s)
nuclear@2 1162 deflate_state *s;
nuclear@2 1163 {
nuclear@2 1164 if (s->bi_valid == 16) {
nuclear@2 1165 put_short(s, s->bi_buf);
nuclear@2 1166 s->bi_buf = 0;
nuclear@2 1167 s->bi_valid = 0;
nuclear@2 1168 } else if (s->bi_valid >= 8) {
nuclear@2 1169 put_byte(s, (Byte)s->bi_buf);
nuclear@2 1170 s->bi_buf >>= 8;
nuclear@2 1171 s->bi_valid -= 8;
nuclear@2 1172 }
nuclear@2 1173 }
nuclear@2 1174
nuclear@2 1175 /* ===========================================================================
nuclear@2 1176 * Flush the bit buffer and align the output on a byte boundary
nuclear@2 1177 */
nuclear@2 1178 local void bi_windup(s)
nuclear@2 1179 deflate_state *s;
nuclear@2 1180 {
nuclear@2 1181 if (s->bi_valid > 8) {
nuclear@2 1182 put_short(s, s->bi_buf);
nuclear@2 1183 } else if (s->bi_valid > 0) {
nuclear@2 1184 put_byte(s, (Byte)s->bi_buf);
nuclear@2 1185 }
nuclear@2 1186 s->bi_buf = 0;
nuclear@2 1187 s->bi_valid = 0;
nuclear@2 1188 #ifdef DEBUG
nuclear@2 1189 s->bits_sent = (s->bits_sent+7) & ~7;
nuclear@2 1190 #endif
nuclear@2 1191 }
nuclear@2 1192
nuclear@2 1193 /* ===========================================================================
nuclear@2 1194 * Copy a stored block, storing first the length and its
nuclear@2 1195 * one's complement if requested.
nuclear@2 1196 */
nuclear@2 1197 local void copy_block(s, buf, len, header)
nuclear@2 1198 deflate_state *s;
nuclear@2 1199 charf *buf; /* the input data */
nuclear@2 1200 unsigned len; /* its length */
nuclear@2 1201 int header; /* true if block header must be written */
nuclear@2 1202 {
nuclear@2 1203 bi_windup(s); /* align on byte boundary */
nuclear@2 1204 s->last_eob_len = 8; /* enough lookahead for inflate */
nuclear@2 1205
nuclear@2 1206 if (header) {
nuclear@2 1207 put_short(s, (ush)len);
nuclear@2 1208 put_short(s, (ush)~len);
nuclear@2 1209 #ifdef DEBUG
nuclear@2 1210 s->bits_sent += 2*16;
nuclear@2 1211 #endif
nuclear@2 1212 }
nuclear@2 1213 #ifdef DEBUG
nuclear@2 1214 s->bits_sent += (ulg)len<<3;
nuclear@2 1215 #endif
nuclear@2 1216 while (len--) {
nuclear@2 1217 put_byte(s, *buf++);
nuclear@2 1218 }
nuclear@2 1219 }