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annotate deps/glpk/src/zlib/trees.c @ 9:33de93886c88

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Import GLPK 4.47
author Alpar Juttner <alpar@cs.elte.hu>
date Sun, 06 Nov 2011 20:59:10 +0100
parents
children
rev   line source
alpar@9 1 /* trees.c -- output deflated data using Huffman coding
alpar@9 2 * Copyright (C) 1995-2010 Jean-loup Gailly
alpar@9 3 * detect_data_type() function provided freely by Cosmin Truta, 2006
alpar@9 4 * For conditions of distribution and use, see copyright notice in zlib.h
alpar@9 5 */
alpar@9 6
alpar@9 7 /*
alpar@9 8 * ALGORITHM
alpar@9 9 *
alpar@9 10 * The "deflation" process uses several Huffman trees. The more
alpar@9 11 * common source values are represented by shorter bit sequences.
alpar@9 12 *
alpar@9 13 * Each code tree is stored in a compressed form which is itself
alpar@9 14 * a Huffman encoding of the lengths of all the code strings (in
alpar@9 15 * ascending order by source values). The actual code strings are
alpar@9 16 * reconstructed from the lengths in the inflate process, as described
alpar@9 17 * in the deflate specification.
alpar@9 18 *
alpar@9 19 * REFERENCES
alpar@9 20 *
alpar@9 21 * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
alpar@9 22 * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
alpar@9 23 *
alpar@9 24 * Storer, James A.
alpar@9 25 * Data Compression: Methods and Theory, pp. 49-50.
alpar@9 26 * Computer Science Press, 1988. ISBN 0-7167-8156-5.
alpar@9 27 *
alpar@9 28 * Sedgewick, R.
alpar@9 29 * Algorithms, p290.
alpar@9 30 * Addison-Wesley, 1983. ISBN 0-201-06672-6.
alpar@9 31 */
alpar@9 32
alpar@9 33 /* @(#) $Id$ */
alpar@9 34
alpar@9 35 /* #define GEN_TREES_H */
alpar@9 36
alpar@9 37 #include "deflate.h"
alpar@9 38
alpar@9 39 #ifdef DEBUG
alpar@9 40 # include <ctype.h>
alpar@9 41 #endif
alpar@9 42
alpar@9 43 /* ===========================================================================
alpar@9 44 * Constants
alpar@9 45 */
alpar@9 46
alpar@9 47 #define MAX_BL_BITS 7
alpar@9 48 /* Bit length codes must not exceed MAX_BL_BITS bits */
alpar@9 49
alpar@9 50 #define END_BLOCK 256
alpar@9 51 /* end of block literal code */
alpar@9 52
alpar@9 53 #define REP_3_6 16
alpar@9 54 /* repeat previous bit length 3-6 times (2 bits of repeat count) */
alpar@9 55
alpar@9 56 #define REPZ_3_10 17
alpar@9 57 /* repeat a zero length 3-10 times (3 bits of repeat count) */
alpar@9 58
alpar@9 59 #define REPZ_11_138 18
alpar@9 60 /* repeat a zero length 11-138 times (7 bits of repeat count) */
alpar@9 61
alpar@9 62 local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
alpar@9 63 = {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};
alpar@9 64
alpar@9 65 local const int extra_dbits[D_CODES] /* extra bits for each distance code */
alpar@9 66 = {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};
alpar@9 67
alpar@9 68 local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
alpar@9 69 = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
alpar@9 70
alpar@9 71 local const uch bl_order[BL_CODES]
alpar@9 72 = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
alpar@9 73 /* The lengths of the bit length codes are sent in order of decreasing
alpar@9 74 * probability, to avoid transmitting the lengths for unused bit length codes.
alpar@9 75 */
alpar@9 76
alpar@9 77 #define Buf_size (8 * 2*sizeof(char))
alpar@9 78 /* Number of bits used within bi_buf. (bi_buf might be implemented on
alpar@9 79 * more than 16 bits on some systems.)
alpar@9 80 */
alpar@9 81
alpar@9 82 /* ===========================================================================
alpar@9 83 * Local data. These are initialized only once.
alpar@9 84 */
alpar@9 85
alpar@9 86 #define DIST_CODE_LEN 512 /* see definition of array dist_code below */
alpar@9 87
alpar@9 88 #if defined(GEN_TREES_H) || !defined(STDC)
alpar@9 89 /* non ANSI compilers may not accept trees.h */
alpar@9 90
alpar@9 91 local ct_data static_ltree[L_CODES+2];
alpar@9 92 /* The static literal tree. Since the bit lengths are imposed, there is no
alpar@9 93 * need for the L_CODES extra codes used during heap construction. However
alpar@9 94 * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
alpar@9 95 * below).
alpar@9 96 */
alpar@9 97
alpar@9 98 local ct_data static_dtree[D_CODES];
alpar@9 99 /* The static distance tree. (Actually a trivial tree since all codes use
alpar@9 100 * 5 bits.)
alpar@9 101 */
alpar@9 102
alpar@9 103 uch _dist_code[DIST_CODE_LEN];
alpar@9 104 /* Distance codes. The first 256 values correspond to the distances
alpar@9 105 * 3 .. 258, the last 256 values correspond to the top 8 bits of
alpar@9 106 * the 15 bit distances.
alpar@9 107 */
alpar@9 108
alpar@9 109 uch _length_code[MAX_MATCH-MIN_MATCH+1];
alpar@9 110 /* length code for each normalized match length (0 == MIN_MATCH) */
alpar@9 111
alpar@9 112 local int base_length[LENGTH_CODES];
alpar@9 113 /* First normalized length for each code (0 = MIN_MATCH) */
alpar@9 114
alpar@9 115 local int base_dist[D_CODES];
alpar@9 116 /* First normalized distance for each code (0 = distance of 1) */
alpar@9 117
alpar@9 118 #else
alpar@9 119 # include "trees.h"
alpar@9 120 #endif /* GEN_TREES_H */
alpar@9 121
alpar@9 122 struct static_tree_desc_s {
alpar@9 123 const ct_data *static_tree; /* static tree or NULL */
alpar@9 124 const intf *extra_bits; /* extra bits for each code or NULL */
alpar@9 125 int extra_base; /* base index for extra_bits */
alpar@9 126 int elems; /* max number of elements in the tree */
alpar@9 127 int max_length; /* max bit length for the codes */
alpar@9 128 };
alpar@9 129
alpar@9 130 local static_tree_desc static_l_desc =
alpar@9 131 {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
alpar@9 132
alpar@9 133 local static_tree_desc static_d_desc =
alpar@9 134 {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
alpar@9 135
alpar@9 136 local static_tree_desc static_bl_desc =
alpar@9 137 {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
alpar@9 138
alpar@9 139 /* ===========================================================================
alpar@9 140 * Local (static) routines in this file.
alpar@9 141 */
alpar@9 142
alpar@9 143 local void tr_static_init OF((void));
alpar@9 144 local void init_block OF((deflate_state *s));
alpar@9 145 local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
alpar@9 146 local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
alpar@9 147 local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
alpar@9 148 local void build_tree OF((deflate_state *s, tree_desc *desc));
alpar@9 149 local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
alpar@9 150 local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
alpar@9 151 local int build_bl_tree OF((deflate_state *s));
alpar@9 152 local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
alpar@9 153 int blcodes));
alpar@9 154 local void compress_block OF((deflate_state *s, ct_data *ltree,
alpar@9 155 ct_data *dtree));
alpar@9 156 local int detect_data_type OF((deflate_state *s));
alpar@9 157 local unsigned bi_reverse OF((unsigned value, int length));
alpar@9 158 local void bi_windup OF((deflate_state *s));
alpar@9 159 local void bi_flush OF((deflate_state *s));
alpar@9 160 local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
alpar@9 161 int header));
alpar@9 162
alpar@9 163 #ifdef GEN_TREES_H
alpar@9 164 local void gen_trees_header OF((void));
alpar@9 165 #endif
alpar@9 166
alpar@9 167 #ifndef DEBUG
alpar@9 168 # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
alpar@9 169 /* Send a code of the given tree. c and tree must not have side effects */
alpar@9 170
alpar@9 171 #else /* DEBUG */
alpar@9 172 # define send_code(s, c, tree) \
alpar@9 173 { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
alpar@9 174 send_bits(s, tree[c].Code, tree[c].Len); }
alpar@9 175 #endif
alpar@9 176
alpar@9 177 /* ===========================================================================
alpar@9 178 * Output a short LSB first on the stream.
alpar@9 179 * IN assertion: there is enough room in pendingBuf.
alpar@9 180 */
alpar@9 181 #define put_short(s, w) { \
alpar@9 182 put_byte(s, (uch)((w) & 0xff)); \
alpar@9 183 put_byte(s, (uch)((ush)(w) >> 8)); \
alpar@9 184 }
alpar@9 185
alpar@9 186 /* ===========================================================================
alpar@9 187 * Send a value on a given number of bits.
alpar@9 188 * IN assertion: length <= 16 and value fits in length bits.
alpar@9 189 */
alpar@9 190 #ifdef DEBUG
alpar@9 191 local void send_bits OF((deflate_state *s, int value, int length));
alpar@9 192
alpar@9 193 local void send_bits(s, value, length)
alpar@9 194 deflate_state *s;
alpar@9 195 int value; /* value to send */
alpar@9 196 int length; /* number of bits */
alpar@9 197 {
alpar@9 198 Tracevv((stderr," l %2d v %4x ", length, value));
alpar@9 199 Assert(length > 0 && length <= 15, "invalid length");
alpar@9 200 s->bits_sent += (ulg)length;
alpar@9 201
alpar@9 202 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
alpar@9 203 * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
alpar@9 204 * unused bits in value.
alpar@9 205 */
alpar@9 206 if (s->bi_valid > (int)Buf_size - length) {
alpar@9 207 s->bi_buf |= (ush)value << s->bi_valid;
alpar@9 208 put_short(s, s->bi_buf);
alpar@9 209 s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
alpar@9 210 s->bi_valid += length - Buf_size;
alpar@9 211 } else {
alpar@9 212 s->bi_buf |= (ush)value << s->bi_valid;
alpar@9 213 s->bi_valid += length;
alpar@9 214 }
alpar@9 215 }
alpar@9 216 #else /* !DEBUG */
alpar@9 217
alpar@9 218 #define send_bits(s, value, length) \
alpar@9 219 { int len = length;\
alpar@9 220 if (s->bi_valid > (int)Buf_size - len) {\
alpar@9 221 int val = value;\
alpar@9 222 s->bi_buf |= (ush)val << s->bi_valid;\
alpar@9 223 put_short(s, s->bi_buf);\
alpar@9 224 s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
alpar@9 225 s->bi_valid += len - Buf_size;\
alpar@9 226 } else {\
alpar@9 227 s->bi_buf |= (ush)(value) << s->bi_valid;\
alpar@9 228 s->bi_valid += len;\
alpar@9 229 }\
alpar@9 230 }
alpar@9 231 #endif /* DEBUG */
alpar@9 232
alpar@9 233
alpar@9 234 /* the arguments must not have side effects */
alpar@9 235
alpar@9 236 /* ===========================================================================
alpar@9 237 * Initialize the various 'constant' tables.
alpar@9 238 */
alpar@9 239 local void tr_static_init()
alpar@9 240 {
alpar@9 241 #if defined(GEN_TREES_H) || !defined(STDC)
alpar@9 242 static int static_init_done = 0;
alpar@9 243 int n; /* iterates over tree elements */
alpar@9 244 int bits; /* bit counter */
alpar@9 245 int length; /* length value */
alpar@9 246 int code; /* code value */
alpar@9 247 int dist; /* distance index */
alpar@9 248 ush bl_count[MAX_BITS+1];
alpar@9 249 /* number of codes at each bit length for an optimal tree */
alpar@9 250
alpar@9 251 if (static_init_done) return;
alpar@9 252
alpar@9 253 /* For some embedded targets, global variables are not initialized: */
alpar@9 254 #ifdef NO_INIT_GLOBAL_POINTERS
alpar@9 255 static_l_desc.static_tree = static_ltree;
alpar@9 256 static_l_desc.extra_bits = extra_lbits;
alpar@9 257 static_d_desc.static_tree = static_dtree;
alpar@9 258 static_d_desc.extra_bits = extra_dbits;
alpar@9 259 static_bl_desc.extra_bits = extra_blbits;
alpar@9 260 #endif
alpar@9 261
alpar@9 262 /* Initialize the mapping length (0..255) -> length code (0..28) */
alpar@9 263 length = 0;
alpar@9 264 for (code = 0; code < LENGTH_CODES-1; code++) {
alpar@9 265 base_length[code] = length;
alpar@9 266 for (n = 0; n < (1<<extra_lbits[code]); n++) {
alpar@9 267 _length_code[length++] = (uch)code;
alpar@9 268 }
alpar@9 269 }
alpar@9 270 Assert (length == 256, "tr_static_init: length != 256");
alpar@9 271 /* Note that the length 255 (match length 258) can be represented
alpar@9 272 * in two different ways: code 284 + 5 bits or code 285, so we
alpar@9 273 * overwrite length_code[255] to use the best encoding:
alpar@9 274 */
alpar@9 275 _length_code[length-1] = (uch)code;
alpar@9 276
alpar@9 277 /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
alpar@9 278 dist = 0;
alpar@9 279 for (code = 0 ; code < 16; code++) {
alpar@9 280 base_dist[code] = dist;
alpar@9 281 for (n = 0; n < (1<<extra_dbits[code]); n++) {
alpar@9 282 _dist_code[dist++] = (uch)code;
alpar@9 283 }
alpar@9 284 }
alpar@9 285 Assert (dist == 256, "tr_static_init: dist != 256");
alpar@9 286 dist >>= 7; /* from now on, all distances are divided by 128 */
alpar@9 287 for ( ; code < D_CODES; code++) {
alpar@9 288 base_dist[code] = dist << 7;
alpar@9 289 for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
alpar@9 290 _dist_code[256 + dist++] = (uch)code;
alpar@9 291 }
alpar@9 292 }
alpar@9 293 Assert (dist == 256, "tr_static_init: 256+dist != 512");
alpar@9 294
alpar@9 295 /* Construct the codes of the static literal tree */
alpar@9 296 for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
alpar@9 297 n = 0;
alpar@9 298 while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
alpar@9 299 while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
alpar@9 300 while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
alpar@9 301 while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
alpar@9 302 /* Codes 286 and 287 do not exist, but we must include them in the
alpar@9 303 * tree construction to get a canonical Huffman tree (longest code
alpar@9 304 * all ones)
alpar@9 305 */
alpar@9 306 gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
alpar@9 307
alpar@9 308 /* The static distance tree is trivial: */
alpar@9 309 for (n = 0; n < D_CODES; n++) {
alpar@9 310 static_dtree[n].Len = 5;
alpar@9 311 static_dtree[n].Code = bi_reverse((unsigned)n, 5);
alpar@9 312 }
alpar@9 313 static_init_done = 1;
alpar@9 314
alpar@9 315 # ifdef GEN_TREES_H
alpar@9 316 gen_trees_header();
alpar@9 317 # endif
alpar@9 318 #endif /* defined(GEN_TREES_H) || !defined(STDC) */
alpar@9 319 }
alpar@9 320
alpar@9 321 /* ===========================================================================
alpar@9 322 * Genererate the file trees.h describing the static trees.
alpar@9 323 */
alpar@9 324 #ifdef GEN_TREES_H
alpar@9 325 # ifndef DEBUG
alpar@9 326 # include <stdio.h>
alpar@9 327 # endif
alpar@9 328
alpar@9 329 # define SEPARATOR(i, last, width) \
alpar@9 330 ((i) == (last)? "\n};\n\n" : \
alpar@9 331 ((i) % (width) == (width)-1 ? ",\n" : ", "))
alpar@9 332
alpar@9 333 void gen_trees_header()
alpar@9 334 {
alpar@9 335 FILE *header = fopen("trees.h", "w");
alpar@9 336 int i;
alpar@9 337
alpar@9 338 Assert (header != NULL, "Can't open trees.h");
alpar@9 339 fprintf(header,
alpar@9 340 "/* header created automatically with -DGEN_TREES_H */\n\n");
alpar@9 341
alpar@9 342 fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
alpar@9 343 for (i = 0; i < L_CODES+2; i++) {
alpar@9 344 fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
alpar@9 345 static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
alpar@9 346 }
alpar@9 347
alpar@9 348 fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
alpar@9 349 for (i = 0; i < D_CODES; i++) {
alpar@9 350 fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
alpar@9 351 static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
alpar@9 352 }
alpar@9 353
alpar@9 354 fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n");
alpar@9 355 for (i = 0; i < DIST_CODE_LEN; i++) {
alpar@9 356 fprintf(header, "%2u%s", _dist_code[i],
alpar@9 357 SEPARATOR(i, DIST_CODE_LEN-1, 20));
alpar@9 358 }
alpar@9 359
alpar@9 360 fprintf(header,
alpar@9 361 "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
alpar@9 362 for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
alpar@9 363 fprintf(header, "%2u%s", _length_code[i],
alpar@9 364 SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
alpar@9 365 }
alpar@9 366
alpar@9 367 fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
alpar@9 368 for (i = 0; i < LENGTH_CODES; i++) {
alpar@9 369 fprintf(header, "%1u%s", base_length[i],
alpar@9 370 SEPARATOR(i, LENGTH_CODES-1, 20));
alpar@9 371 }
alpar@9 372
alpar@9 373 fprintf(header, "local const int base_dist[D_CODES] = {\n");
alpar@9 374 for (i = 0; i < D_CODES; i++) {
alpar@9 375 fprintf(header, "%5u%s", base_dist[i],
alpar@9 376 SEPARATOR(i, D_CODES-1, 10));
alpar@9 377 }
alpar@9 378
alpar@9 379 fclose(header);
alpar@9 380 }
alpar@9 381 #endif /* GEN_TREES_H */
alpar@9 382
alpar@9 383 /* ===========================================================================
alpar@9 384 * Initialize the tree data structures for a new zlib stream.
alpar@9 385 */
alpar@9 386 void ZLIB_INTERNAL _tr_init(s)
alpar@9 387 deflate_state *s;
alpar@9 388 {
alpar@9 389 tr_static_init();
alpar@9 390
alpar@9 391 s->l_desc.dyn_tree = s->dyn_ltree;
alpar@9 392 s->l_desc.stat_desc = &static_l_desc;
alpar@9 393
alpar@9 394 s->d_desc.dyn_tree = s->dyn_dtree;
alpar@9 395 s->d_desc.stat_desc = &static_d_desc;
alpar@9 396
alpar@9 397 s->bl_desc.dyn_tree = s->bl_tree;
alpar@9 398 s->bl_desc.stat_desc = &static_bl_desc;
alpar@9 399
alpar@9 400 s->bi_buf = 0;
alpar@9 401 s->bi_valid = 0;
alpar@9 402 s->last_eob_len = 8; /* enough lookahead for inflate */
alpar@9 403 #ifdef DEBUG
alpar@9 404 s->compressed_len = 0L;
alpar@9 405 s->bits_sent = 0L;
alpar@9 406 #endif
alpar@9 407
alpar@9 408 /* Initialize the first block of the first file: */
alpar@9 409 init_block(s);
alpar@9 410 }
alpar@9 411
alpar@9 412 /* ===========================================================================
alpar@9 413 * Initialize a new block.
alpar@9 414 */
alpar@9 415 local void init_block(s)
alpar@9 416 deflate_state *s;
alpar@9 417 {
alpar@9 418 int n; /* iterates over tree elements */
alpar@9 419
alpar@9 420 /* Initialize the trees. */
alpar@9 421 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
alpar@9 422 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
alpar@9 423 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
alpar@9 424
alpar@9 425 s->dyn_ltree[END_BLOCK].Freq = 1;
alpar@9 426 s->opt_len = s->static_len = 0L;
alpar@9 427 s->last_lit = s->matches = 0;
alpar@9 428 }
alpar@9 429
alpar@9 430 #define SMALLEST 1
alpar@9 431 /* Index within the heap array of least frequent node in the Huffman tree */
alpar@9 432
alpar@9 433
alpar@9 434 /* ===========================================================================
alpar@9 435 * Remove the smallest element from the heap and recreate the heap with
alpar@9 436 * one less element. Updates heap and heap_len.
alpar@9 437 */
alpar@9 438 #define pqremove(s, tree, top) \
alpar@9 439 {\
alpar@9 440 top = s->heap[SMALLEST]; \
alpar@9 441 s->heap[SMALLEST] = s->heap[s->heap_len--]; \
alpar@9 442 pqdownheap(s, tree, SMALLEST); \
alpar@9 443 }
alpar@9 444
alpar@9 445 /* ===========================================================================
alpar@9 446 * Compares to subtrees, using the tree depth as tie breaker when
alpar@9 447 * the subtrees have equal frequency. This minimizes the worst case length.
alpar@9 448 */
alpar@9 449 #define smaller(tree, n, m, depth) \
alpar@9 450 (tree[n].Freq < tree[m].Freq || \
alpar@9 451 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
alpar@9 452
alpar@9 453 /* ===========================================================================
alpar@9 454 * Restore the heap property by moving down the tree starting at node k,
alpar@9 455 * exchanging a node with the smallest of its two sons if necessary, stopping
alpar@9 456 * when the heap property is re-established (each father smaller than its
alpar@9 457 * two sons).
alpar@9 458 */
alpar@9 459 local void pqdownheap(s, tree, k)
alpar@9 460 deflate_state *s;
alpar@9 461 ct_data *tree; /* the tree to restore */
alpar@9 462 int k; /* node to move down */
alpar@9 463 {
alpar@9 464 int v = s->heap[k];
alpar@9 465 int j = k << 1; /* left son of k */
alpar@9 466 while (j <= s->heap_len) {
alpar@9 467 /* Set j to the smallest of the two sons: */
alpar@9 468 if (j < s->heap_len &&
alpar@9 469 smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
alpar@9 470 j++;
alpar@9 471 }
alpar@9 472 /* Exit if v is smaller than both sons */
alpar@9 473 if (smaller(tree, v, s->heap[j], s->depth)) break;
alpar@9 474
alpar@9 475 /* Exchange v with the smallest son */
alpar@9 476 s->heap[k] = s->heap[j]; k = j;
alpar@9 477
alpar@9 478 /* And continue down the tree, setting j to the left son of k */
alpar@9 479 j <<= 1;
alpar@9 480 }
alpar@9 481 s->heap[k] = v;
alpar@9 482 }
alpar@9 483
alpar@9 484 /* ===========================================================================
alpar@9 485 * Compute the optimal bit lengths for a tree and update the total bit length
alpar@9 486 * for the current block.
alpar@9 487 * IN assertion: the fields freq and dad are set, heap[heap_max] and
alpar@9 488 * above are the tree nodes sorted by increasing frequency.
alpar@9 489 * OUT assertions: the field len is set to the optimal bit length, the
alpar@9 490 * array bl_count contains the frequencies for each bit length.
alpar@9 491 * The length opt_len is updated; static_len is also updated if stree is
alpar@9 492 * not null.
alpar@9 493 */
alpar@9 494 local void gen_bitlen(s, desc)
alpar@9 495 deflate_state *s;
alpar@9 496 tree_desc *desc; /* the tree descriptor */
alpar@9 497 {
alpar@9 498 ct_data *tree = desc->dyn_tree;
alpar@9 499 int max_code = desc->max_code;
alpar@9 500 const ct_data *stree = desc->stat_desc->static_tree;
alpar@9 501 const intf *extra = desc->stat_desc->extra_bits;
alpar@9 502 int base = desc->stat_desc->extra_base;
alpar@9 503 int max_length = desc->stat_desc->max_length;
alpar@9 504 int h; /* heap index */
alpar@9 505 int n, m; /* iterate over the tree elements */
alpar@9 506 int bits; /* bit length */
alpar@9 507 int xbits; /* extra bits */
alpar@9 508 ush f; /* frequency */
alpar@9 509 int overflow = 0; /* number of elements with bit length too large */
alpar@9 510
alpar@9 511 for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
alpar@9 512
alpar@9 513 /* In a first pass, compute the optimal bit lengths (which may
alpar@9 514 * overflow in the case of the bit length tree).
alpar@9 515 */
alpar@9 516 tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
alpar@9 517
alpar@9 518 for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
alpar@9 519 n = s->heap[h];
alpar@9 520 bits = tree[tree[n].Dad].Len + 1;
alpar@9 521 if (bits > max_length) bits = max_length, overflow++;
alpar@9 522 tree[n].Len = (ush)bits;
alpar@9 523 /* We overwrite tree[n].Dad which is no longer needed */
alpar@9 524
alpar@9 525 if (n > max_code) continue; /* not a leaf node */
alpar@9 526
alpar@9 527 s->bl_count[bits]++;
alpar@9 528 xbits = 0;
alpar@9 529 if (n >= base) xbits = extra[n-base];
alpar@9 530 f = tree[n].Freq;
alpar@9 531 s->opt_len += (ulg)f * (bits + xbits);
alpar@9 532 if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
alpar@9 533 }
alpar@9 534 if (overflow == 0) return;
alpar@9 535
alpar@9 536 Trace((stderr,"\nbit length overflow\n"));
alpar@9 537 /* This happens for example on obj2 and pic of the Calgary corpus */
alpar@9 538
alpar@9 539 /* Find the first bit length which could increase: */
alpar@9 540 do {
alpar@9 541 bits = max_length-1;
alpar@9 542 while (s->bl_count[bits] == 0) bits--;
alpar@9 543 s->bl_count[bits]--; /* move one leaf down the tree */
alpar@9 544 s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
alpar@9 545 s->bl_count[max_length]--;
alpar@9 546 /* The brother of the overflow item also moves one step up,
alpar@9 547 * but this does not affect bl_count[max_length]
alpar@9 548 */
alpar@9 549 overflow -= 2;
alpar@9 550 } while (overflow > 0);
alpar@9 551
alpar@9 552 /* Now recompute all bit lengths, scanning in increasing frequency.
alpar@9 553 * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
alpar@9 554 * lengths instead of fixing only the wrong ones. This idea is taken
alpar@9 555 * from 'ar' written by Haruhiko Okumura.)
alpar@9 556 */
alpar@9 557 for (bits = max_length; bits != 0; bits--) {
alpar@9 558 n = s->bl_count[bits];
alpar@9 559 while (n != 0) {
alpar@9 560 m = s->heap[--h];
alpar@9 561 if (m > max_code) continue;
alpar@9 562 if ((unsigned) tree[m].Len != (unsigned) bits) {
alpar@9 563 Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
alpar@9 564 s->opt_len += ((long)bits - (long)tree[m].Len)
alpar@9 565 *(long)tree[m].Freq;
alpar@9 566 tree[m].Len = (ush)bits;
alpar@9 567 }
alpar@9 568 n--;
alpar@9 569 }
alpar@9 570 }
alpar@9 571 }
alpar@9 572
alpar@9 573 /* ===========================================================================
alpar@9 574 * Generate the codes for a given tree and bit counts (which need not be
alpar@9 575 * optimal).
alpar@9 576 * IN assertion: the array bl_count contains the bit length statistics for
alpar@9 577 * the given tree and the field len is set for all tree elements.
alpar@9 578 * OUT assertion: the field code is set for all tree elements of non
alpar@9 579 * zero code length.
alpar@9 580 */
alpar@9 581 local void gen_codes (tree, max_code, bl_count)
alpar@9 582 ct_data *tree; /* the tree to decorate */
alpar@9 583 int max_code; /* largest code with non zero frequency */
alpar@9 584 ushf *bl_count; /* number of codes at each bit length */
alpar@9 585 {
alpar@9 586 ush next_code[MAX_BITS+1]; /* next code value for each bit length */
alpar@9 587 ush code = 0; /* running code value */
alpar@9 588 int bits; /* bit index */
alpar@9 589 int n; /* code index */
alpar@9 590
alpar@9 591 /* The distribution counts are first used to generate the code values
alpar@9 592 * without bit reversal.
alpar@9 593 */
alpar@9 594 for (bits = 1; bits <= MAX_BITS; bits++) {
alpar@9 595 next_code[bits] = code = (code + bl_count[bits-1]) << 1;
alpar@9 596 }
alpar@9 597 /* Check that the bit counts in bl_count are consistent. The last code
alpar@9 598 * must be all ones.
alpar@9 599 */
alpar@9 600 Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
alpar@9 601 "inconsistent bit counts");
alpar@9 602 Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
alpar@9 603
alpar@9 604 for (n = 0; n <= max_code; n++) {
alpar@9 605 int len = tree[n].Len;
alpar@9 606 if (len == 0) continue;
alpar@9 607 /* Now reverse the bits */
alpar@9 608 tree[n].Code = bi_reverse(next_code[len]++, len);
alpar@9 609
alpar@9 610 Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
alpar@9 611 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
alpar@9 612 }
alpar@9 613 }
alpar@9 614
alpar@9 615 /* ===========================================================================
alpar@9 616 * Construct one Huffman tree and assigns the code bit strings and lengths.
alpar@9 617 * Update the total bit length for the current block.
alpar@9 618 * IN assertion: the field freq is set for all tree elements.
alpar@9 619 * OUT assertions: the fields len and code are set to the optimal bit length
alpar@9 620 * and corresponding code. The length opt_len is updated; static_len is
alpar@9 621 * also updated if stree is not null. The field max_code is set.
alpar@9 622 */
alpar@9 623 local void build_tree(s, desc)
alpar@9 624 deflate_state *s;
alpar@9 625 tree_desc *desc; /* the tree descriptor */
alpar@9 626 {
alpar@9 627 ct_data *tree = desc->dyn_tree;
alpar@9 628 const ct_data *stree = desc->stat_desc->static_tree;
alpar@9 629 int elems = desc->stat_desc->elems;
alpar@9 630 int n, m; /* iterate over heap elements */
alpar@9 631 int max_code = -1; /* largest code with non zero frequency */
alpar@9 632 int node; /* new node being created */
alpar@9 633
alpar@9 634 /* Construct the initial heap, with least frequent element in
alpar@9 635 * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
alpar@9 636 * heap[0] is not used.
alpar@9 637 */
alpar@9 638 s->heap_len = 0, s->heap_max = HEAP_SIZE;
alpar@9 639
alpar@9 640 for (n = 0; n < elems; n++) {
alpar@9 641 if (tree[n].Freq != 0) {
alpar@9 642 s->heap[++(s->heap_len)] = max_code = n;
alpar@9 643 s->depth[n] = 0;
alpar@9 644 } else {
alpar@9 645 tree[n].Len = 0;
alpar@9 646 }
alpar@9 647 }
alpar@9 648
alpar@9 649 /* The pkzip format requires that at least one distance code exists,
alpar@9 650 * and that at least one bit should be sent even if there is only one
alpar@9 651 * possible code. So to avoid special checks later on we force at least
alpar@9 652 * two codes of non zero frequency.
alpar@9 653 */
alpar@9 654 while (s->heap_len < 2) {
alpar@9 655 node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
alpar@9 656 tree[node].Freq = 1;
alpar@9 657 s->depth[node] = 0;
alpar@9 658 s->opt_len--; if (stree) s->static_len -= stree[node].Len;
alpar@9 659 /* node is 0 or 1 so it does not have extra bits */
alpar@9 660 }
alpar@9 661 desc->max_code = max_code;
alpar@9 662
alpar@9 663 /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
alpar@9 664 * establish sub-heaps of increasing lengths:
alpar@9 665 */
alpar@9 666 for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
alpar@9 667
alpar@9 668 /* Construct the Huffman tree by repeatedly combining the least two
alpar@9 669 * frequent nodes.
alpar@9 670 */
alpar@9 671 node = elems; /* next internal node of the tree */
alpar@9 672 do {
alpar@9 673 pqremove(s, tree, n); /* n = node of least frequency */
alpar@9 674 m = s->heap[SMALLEST]; /* m = node of next least frequency */
alpar@9 675
alpar@9 676 s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
alpar@9 677 s->heap[--(s->heap_max)] = m;
alpar@9 678
alpar@9 679 /* Create a new node father of n and m */
alpar@9 680 tree[node].Freq = tree[n].Freq + tree[m].Freq;
alpar@9 681 s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
alpar@9 682 s->depth[n] : s->depth[m]) + 1);
alpar@9 683 tree[n].Dad = tree[m].Dad = (ush)node;
alpar@9 684 #ifdef DUMP_BL_TREE
alpar@9 685 if (tree == s->bl_tree) {
alpar@9 686 fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
alpar@9 687 node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
alpar@9 688 }
alpar@9 689 #endif
alpar@9 690 /* and insert the new node in the heap */
alpar@9 691 s->heap[SMALLEST] = node++;
alpar@9 692 pqdownheap(s, tree, SMALLEST);
alpar@9 693
alpar@9 694 } while (s->heap_len >= 2);
alpar@9 695
alpar@9 696 s->heap[--(s->heap_max)] = s->heap[SMALLEST];
alpar@9 697
alpar@9 698 /* At this point, the fields freq and dad are set. We can now
alpar@9 699 * generate the bit lengths.
alpar@9 700 */
alpar@9 701 gen_bitlen(s, (tree_desc *)desc);
alpar@9 702
alpar@9 703 /* The field len is now set, we can generate the bit codes */
alpar@9 704 gen_codes ((ct_data *)tree, max_code, s->bl_count);
alpar@9 705 }
alpar@9 706
alpar@9 707 /* ===========================================================================
alpar@9 708 * Scan a literal or distance tree to determine the frequencies of the codes
alpar@9 709 * in the bit length tree.
alpar@9 710 */
alpar@9 711 local void scan_tree (s, tree, max_code)
alpar@9 712 deflate_state *s;
alpar@9 713 ct_data *tree; /* the tree to be scanned */
alpar@9 714 int max_code; /* and its largest code of non zero frequency */
alpar@9 715 {
alpar@9 716 int n; /* iterates over all tree elements */
alpar@9 717 int prevlen = -1; /* last emitted length */
alpar@9 718 int curlen; /* length of current code */
alpar@9 719 int nextlen = tree[0].Len; /* length of next code */
alpar@9 720 int count = 0; /* repeat count of the current code */
alpar@9 721 int max_count = 7; /* max repeat count */
alpar@9 722 int min_count = 4; /* min repeat count */
alpar@9 723
alpar@9 724 if (nextlen == 0) max_count = 138, min_count = 3;
alpar@9 725 tree[max_code+1].Len = (ush)0xffff; /* guard */
alpar@9 726
alpar@9 727 for (n = 0; n <= max_code; n++) {
alpar@9 728 curlen = nextlen; nextlen = tree[n+1].Len;
alpar@9 729 if (++count < max_count && curlen == nextlen) {
alpar@9 730 continue;
alpar@9 731 } else if (count < min_count) {
alpar@9 732 s->bl_tree[curlen].Freq += count;
alpar@9 733 } else if (curlen != 0) {
alpar@9 734 if (curlen != prevlen) s->bl_tree[curlen].Freq++;
alpar@9 735 s->bl_tree[REP_3_6].Freq++;
alpar@9 736 } else if (count <= 10) {
alpar@9 737 s->bl_tree[REPZ_3_10].Freq++;
alpar@9 738 } else {
alpar@9 739 s->bl_tree[REPZ_11_138].Freq++;
alpar@9 740 }
alpar@9 741 count = 0; prevlen = curlen;
alpar@9 742 if (nextlen == 0) {
alpar@9 743 max_count = 138, min_count = 3;
alpar@9 744 } else if (curlen == nextlen) {
alpar@9 745 max_count = 6, min_count = 3;
alpar@9 746 } else {
alpar@9 747 max_count = 7, min_count = 4;
alpar@9 748 }
alpar@9 749 }
alpar@9 750 }
alpar@9 751
alpar@9 752 /* ===========================================================================
alpar@9 753 * Send a literal or distance tree in compressed form, using the codes in
alpar@9 754 * bl_tree.
alpar@9 755 */
alpar@9 756 local void send_tree (s, tree, max_code)
alpar@9 757 deflate_state *s;
alpar@9 758 ct_data *tree; /* the tree to be scanned */
alpar@9 759 int max_code; /* and its largest code of non zero frequency */
alpar@9 760 {
alpar@9 761 int n; /* iterates over all tree elements */
alpar@9 762 int prevlen = -1; /* last emitted length */
alpar@9 763 int curlen; /* length of current code */
alpar@9 764 int nextlen = tree[0].Len; /* length of next code */
alpar@9 765 int count = 0; /* repeat count of the current code */
alpar@9 766 int max_count = 7; /* max repeat count */
alpar@9 767 int min_count = 4; /* min repeat count */
alpar@9 768
alpar@9 769 /* tree[max_code+1].Len = -1; */ /* guard already set */
alpar@9 770 if (nextlen == 0) max_count = 138, min_count = 3;
alpar@9 771
alpar@9 772 for (n = 0; n <= max_code; n++) {
alpar@9 773 curlen = nextlen; nextlen = tree[n+1].Len;
alpar@9 774 if (++count < max_count && curlen == nextlen) {
alpar@9 775 continue;
alpar@9 776 } else if (count < min_count) {
alpar@9 777 do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
alpar@9 778
alpar@9 779 } else if (curlen != 0) {
alpar@9 780 if (curlen != prevlen) {
alpar@9 781 send_code(s, curlen, s->bl_tree); count--;
alpar@9 782 }
alpar@9 783 Assert(count >= 3 && count <= 6, " 3_6?");
alpar@9 784 send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
alpar@9 785
alpar@9 786 } else if (count <= 10) {
alpar@9 787 send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
alpar@9 788
alpar@9 789 } else {
alpar@9 790 send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
alpar@9 791 }
alpar@9 792 count = 0; prevlen = curlen;
alpar@9 793 if (nextlen == 0) {
alpar@9 794 max_count = 138, min_count = 3;
alpar@9 795 } else if (curlen == nextlen) {
alpar@9 796 max_count = 6, min_count = 3;
alpar@9 797 } else {
alpar@9 798 max_count = 7, min_count = 4;
alpar@9 799 }
alpar@9 800 }
alpar@9 801 }
alpar@9 802
alpar@9 803 /* ===========================================================================
alpar@9 804 * Construct the Huffman tree for the bit lengths and return the index in
alpar@9 805 * bl_order of the last bit length code to send.
alpar@9 806 */
alpar@9 807 local int build_bl_tree(s)
alpar@9 808 deflate_state *s;
alpar@9 809 {
alpar@9 810 int max_blindex; /* index of last bit length code of non zero freq */
alpar@9 811
alpar@9 812 /* Determine the bit length frequencies for literal and distance trees */
alpar@9 813 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
alpar@9 814 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
alpar@9 815
alpar@9 816 /* Build the bit length tree: */
alpar@9 817 build_tree(s, (tree_desc *)(&(s->bl_desc)));
alpar@9 818 /* opt_len now includes the length of the tree representations, except
alpar@9 819 * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
alpar@9 820 */
alpar@9 821
alpar@9 822 /* Determine the number of bit length codes to send. The pkzip format
alpar@9 823 * requires that at least 4 bit length codes be sent. (appnote.txt says
alpar@9 824 * 3 but the actual value used is 4.)
alpar@9 825 */
alpar@9 826 for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
alpar@9 827 if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
alpar@9 828 }
alpar@9 829 /* Update opt_len to include the bit length tree and counts */
alpar@9 830 s->opt_len += 3*(max_blindex+1) + 5+5+4;
alpar@9 831 Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
alpar@9 832 s->opt_len, s->static_len));
alpar@9 833
alpar@9 834 return max_blindex;
alpar@9 835 }
alpar@9 836
alpar@9 837 /* ===========================================================================
alpar@9 838 * Send the header for a block using dynamic Huffman trees: the counts, the
alpar@9 839 * lengths of the bit length codes, the literal tree and the distance tree.
alpar@9 840 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
alpar@9 841 */
alpar@9 842 local void send_all_trees(s, lcodes, dcodes, blcodes)
alpar@9 843 deflate_state *s;
alpar@9 844 int lcodes, dcodes, blcodes; /* number of codes for each tree */
alpar@9 845 {
alpar@9 846 int rank; /* index in bl_order */
alpar@9 847
alpar@9 848 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
alpar@9 849 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
alpar@9 850 "too many codes");
alpar@9 851 Tracev((stderr, "\nbl counts: "));
alpar@9 852 send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
alpar@9 853 send_bits(s, dcodes-1, 5);
alpar@9 854 send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
alpar@9 855 for (rank = 0; rank < blcodes; rank++) {
alpar@9 856 Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
alpar@9 857 send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
alpar@9 858 }
alpar@9 859 Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
alpar@9 860
alpar@9 861 send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
alpar@9 862 Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
alpar@9 863
alpar@9 864 send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
alpar@9 865 Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
alpar@9 866 }
alpar@9 867
alpar@9 868 /* ===========================================================================
alpar@9 869 * Send a stored block
alpar@9 870 */
alpar@9 871 void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)
alpar@9 872 deflate_state *s;
alpar@9 873 charf *buf; /* input block */
alpar@9 874 ulg stored_len; /* length of input block */
alpar@9 875 int last; /* one if this is the last block for a file */
alpar@9 876 {
alpar@9 877 send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */
alpar@9 878 #ifdef DEBUG
alpar@9 879 s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
alpar@9 880 s->compressed_len += (stored_len + 4) << 3;
alpar@9 881 #endif
alpar@9 882 copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
alpar@9 883 }
alpar@9 884
alpar@9 885 /* ===========================================================================
alpar@9 886 * Send one empty static block to give enough lookahead for inflate.
alpar@9 887 * This takes 10 bits, of which 7 may remain in the bit buffer.
alpar@9 888 * The current inflate code requires 9 bits of lookahead. If the
alpar@9 889 * last two codes for the previous block (real code plus EOB) were coded
alpar@9 890 * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode
alpar@9 891 * the last real code. In this case we send two empty static blocks instead
alpar@9 892 * of one. (There are no problems if the previous block is stored or fixed.)
alpar@9 893 * To simplify the code, we assume the worst case of last real code encoded
alpar@9 894 * on one bit only.
alpar@9 895 */
alpar@9 896 void ZLIB_INTERNAL _tr_align(s)
alpar@9 897 deflate_state *s;
alpar@9 898 {
alpar@9 899 send_bits(s, STATIC_TREES<<1, 3);
alpar@9 900 send_code(s, END_BLOCK, static_ltree);
alpar@9 901 #ifdef DEBUG
alpar@9 902 s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
alpar@9 903 #endif
alpar@9 904 bi_flush(s);
alpar@9 905 /* Of the 10 bits for the empty block, we have already sent
alpar@9 906 * (10 - bi_valid) bits. The lookahead for the last real code (before
alpar@9 907 * the EOB of the previous block) was thus at least one plus the length
alpar@9 908 * of the EOB plus what we have just sent of the empty static block.
alpar@9 909 */
alpar@9 910 if (1 + s->last_eob_len + 10 - s->bi_valid < 9) {
alpar@9 911 send_bits(s, STATIC_TREES<<1, 3);
alpar@9 912 send_code(s, END_BLOCK, static_ltree);
alpar@9 913 #ifdef DEBUG
alpar@9 914 s->compressed_len += 10L;
alpar@9 915 #endif
alpar@9 916 bi_flush(s);
alpar@9 917 }
alpar@9 918 s->last_eob_len = 7;
alpar@9 919 }
alpar@9 920
alpar@9 921 /* ===========================================================================
alpar@9 922 * Determine the best encoding for the current block: dynamic trees, static
alpar@9 923 * trees or store, and output the encoded block to the zip file.
alpar@9 924 */
alpar@9 925 void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
alpar@9 926 deflate_state *s;
alpar@9 927 charf *buf; /* input block, or NULL if too old */
alpar@9 928 ulg stored_len; /* length of input block */
alpar@9 929 int last; /* one if this is the last block for a file */
alpar@9 930 {
alpar@9 931 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
alpar@9 932 int max_blindex = 0; /* index of last bit length code of non zero freq */
alpar@9 933
alpar@9 934 /* Build the Huffman trees unless a stored block is forced */
alpar@9 935 if (s->level > 0) {
alpar@9 936
alpar@9 937 /* Check if the file is binary or text */
alpar@9 938 if (s->strm->data_type == Z_UNKNOWN)
alpar@9 939 s->strm->data_type = detect_data_type(s);
alpar@9 940
alpar@9 941 /* Construct the literal and distance trees */
alpar@9 942 build_tree(s, (tree_desc *)(&(s->l_desc)));
alpar@9 943 Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
alpar@9 944 s->static_len));
alpar@9 945
alpar@9 946 build_tree(s, (tree_desc *)(&(s->d_desc)));
alpar@9 947 Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
alpar@9 948 s->static_len));
alpar@9 949 /* At this point, opt_len and static_len are the total bit lengths of
alpar@9 950 * the compressed block data, excluding the tree representations.
alpar@9 951 */
alpar@9 952
alpar@9 953 /* Build the bit length tree for the above two trees, and get the index
alpar@9 954 * in bl_order of the last bit length code to send.
alpar@9 955 */
alpar@9 956 max_blindex = build_bl_tree(s);
alpar@9 957
alpar@9 958 /* Determine the best encoding. Compute the block lengths in bytes. */
alpar@9 959 opt_lenb = (s->opt_len+3+7)>>3;
alpar@9 960 static_lenb = (s->static_len+3+7)>>3;
alpar@9 961
alpar@9 962 Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
alpar@9 963 opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
alpar@9 964 s->last_lit));
alpar@9 965
alpar@9 966 if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
alpar@9 967
alpar@9 968 } else {
alpar@9 969 Assert(buf != (char*)0, "lost buf");
alpar@9 970 opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
alpar@9 971 }
alpar@9 972
alpar@9 973 #ifdef FORCE_STORED
alpar@9 974 if (buf != (char*)0) { /* force stored block */
alpar@9 975 #else
alpar@9 976 if (stored_len+4 <= opt_lenb && buf != (char*)0) {
alpar@9 977 /* 4: two words for the lengths */
alpar@9 978 #endif
alpar@9 979 /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
alpar@9 980 * Otherwise we can't have processed more than WSIZE input bytes since
alpar@9 981 * the last block flush, because compression would have been
alpar@9 982 * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
alpar@9 983 * transform a block into a stored block.
alpar@9 984 */
alpar@9 985 _tr_stored_block(s, buf, stored_len, last);
alpar@9 986
alpar@9 987 #ifdef FORCE_STATIC
alpar@9 988 } else if (static_lenb >= 0) { /* force static trees */
alpar@9 989 #else
alpar@9 990 } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
alpar@9 991 #endif
alpar@9 992 send_bits(s, (STATIC_TREES<<1)+last, 3);
alpar@9 993 compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree);
alpar@9 994 #ifdef DEBUG
alpar@9 995 s->compressed_len += 3 + s->static_len;
alpar@9 996 #endif
alpar@9 997 } else {
alpar@9 998 send_bits(s, (DYN_TREES<<1)+last, 3);
alpar@9 999 send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
alpar@9 1000 max_blindex+1);
alpar@9 1001 compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree);
alpar@9 1002 #ifdef DEBUG
alpar@9 1003 s->compressed_len += 3 + s->opt_len;
alpar@9 1004 #endif
alpar@9 1005 }
alpar@9 1006 Assert (s->compressed_len == s->bits_sent, "bad compressed size");
alpar@9 1007 /* The above check is made mod 2^32, for files larger than 512 MB
alpar@9 1008 * and uLong implemented on 32 bits.
alpar@9 1009 */
alpar@9 1010 init_block(s);
alpar@9 1011
alpar@9 1012 if (last) {
alpar@9 1013 bi_windup(s);
alpar@9 1014 #ifdef DEBUG
alpar@9 1015 s->compressed_len += 7; /* align on byte boundary */
alpar@9 1016 #endif
alpar@9 1017 }
alpar@9 1018 Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
alpar@9 1019 s->compressed_len-7*last));
alpar@9 1020 }
alpar@9 1021
alpar@9 1022 /* ===========================================================================
alpar@9 1023 * Save the match info and tally the frequency counts. Return true if
alpar@9 1024 * the current block must be flushed.
alpar@9 1025 */
alpar@9 1026 int ZLIB_INTERNAL _tr_tally (s, dist, lc)
alpar@9 1027 deflate_state *s;
alpar@9 1028 unsigned dist; /* distance of matched string */
alpar@9 1029 unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
alpar@9 1030 {
alpar@9 1031 s->d_buf[s->last_lit] = (ush)dist;
alpar@9 1032 s->l_buf[s->last_lit++] = (uch)lc;
alpar@9 1033 if (dist == 0) {
alpar@9 1034 /* lc is the unmatched char */
alpar@9 1035 s->dyn_ltree[lc].Freq++;
alpar@9 1036 } else {
alpar@9 1037 s->matches++;
alpar@9 1038 /* Here, lc is the match length - MIN_MATCH */
alpar@9 1039 dist--; /* dist = match distance - 1 */
alpar@9 1040 Assert((ush)dist < (ush)MAX_DIST(s) &&
alpar@9 1041 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
alpar@9 1042 (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
alpar@9 1043
alpar@9 1044 s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
alpar@9 1045 s->dyn_dtree[d_code(dist)].Freq++;
alpar@9 1046 }
alpar@9 1047
alpar@9 1048 #ifdef TRUNCATE_BLOCK
alpar@9 1049 /* Try to guess if it is profitable to stop the current block here */
alpar@9 1050 if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
alpar@9 1051 /* Compute an upper bound for the compressed length */
alpar@9 1052 ulg out_length = (ulg)s->last_lit*8L;
alpar@9 1053 ulg in_length = (ulg)((long)s->strstart - s->block_start);
alpar@9 1054 int dcode;
alpar@9 1055 for (dcode = 0; dcode < D_CODES; dcode++) {
alpar@9 1056 out_length += (ulg)s->dyn_dtree[dcode].Freq *
alpar@9 1057 (5L+extra_dbits[dcode]);
alpar@9 1058 }
alpar@9 1059 out_length >>= 3;
alpar@9 1060 Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
alpar@9 1061 s->last_lit, in_length, out_length,
alpar@9 1062 100L - out_length*100L/in_length));
alpar@9 1063 if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
alpar@9 1064 }
alpar@9 1065 #endif
alpar@9 1066 return (s->last_lit == s->lit_bufsize-1);
alpar@9 1067 /* We avoid equality with lit_bufsize because of wraparound at 64K
alpar@9 1068 * on 16 bit machines and because stored blocks are restricted to
alpar@9 1069 * 64K-1 bytes.
alpar@9 1070 */
alpar@9 1071 }
alpar@9 1072
alpar@9 1073 /* ===========================================================================
alpar@9 1074 * Send the block data compressed using the given Huffman trees
alpar@9 1075 */
alpar@9 1076 local void compress_block(s, ltree, dtree)
alpar@9 1077 deflate_state *s;
alpar@9 1078 ct_data *ltree; /* literal tree */
alpar@9 1079 ct_data *dtree; /* distance tree */
alpar@9 1080 {
alpar@9 1081 unsigned dist; /* distance of matched string */
alpar@9 1082 int lc; /* match length or unmatched char (if dist == 0) */
alpar@9 1083 unsigned lx = 0; /* running index in l_buf */
alpar@9 1084 unsigned code; /* the code to send */
alpar@9 1085 int extra; /* number of extra bits to send */
alpar@9 1086
alpar@9 1087 if (s->last_lit != 0) do {
alpar@9 1088 dist = s->d_buf[lx];
alpar@9 1089 lc = s->l_buf[lx++];
alpar@9 1090 if (dist == 0) {
alpar@9 1091 send_code(s, lc, ltree); /* send a literal byte */
alpar@9 1092 Tracecv(isgraph(lc), (stderr," '%c' ", lc));
alpar@9 1093 } else {
alpar@9 1094 /* Here, lc is the match length - MIN_MATCH */
alpar@9 1095 code = _length_code[lc];
alpar@9 1096 send_code(s, code+LITERALS+1, ltree); /* send the length code */
alpar@9 1097 extra = extra_lbits[code];
alpar@9 1098 if (extra != 0) {
alpar@9 1099 lc -= base_length[code];
alpar@9 1100 send_bits(s, lc, extra); /* send the extra length bits */
alpar@9 1101 }
alpar@9 1102 dist--; /* dist is now the match distance - 1 */
alpar@9 1103 code = d_code(dist);
alpar@9 1104 Assert (code < D_CODES, "bad d_code");
alpar@9 1105
alpar@9 1106 send_code(s, code, dtree); /* send the distance code */
alpar@9 1107 extra = extra_dbits[code];
alpar@9 1108 if (extra != 0) {
alpar@9 1109 dist -= base_dist[code];
alpar@9 1110 send_bits(s, dist, extra); /* send the extra distance bits */
alpar@9 1111 }
alpar@9 1112 } /* literal or match pair ? */
alpar@9 1113
alpar@9 1114 /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
alpar@9 1115 Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
alpar@9 1116 "pendingBuf overflow");
alpar@9 1117
alpar@9 1118 } while (lx < s->last_lit);
alpar@9 1119
alpar@9 1120 send_code(s, END_BLOCK, ltree);
alpar@9 1121 s->last_eob_len = ltree[END_BLOCK].Len;
alpar@9 1122 }
alpar@9 1123
alpar@9 1124 /* ===========================================================================
alpar@9 1125 * Check if the data type is TEXT or BINARY, using the following algorithm:
alpar@9 1126 * - TEXT if the two conditions below are satisfied:
alpar@9 1127 * a) There are no non-portable control characters belonging to the
alpar@9 1128 * "black list" (0..6, 14..25, 28..31).
alpar@9 1129 * b) There is at least one printable character belonging to the
alpar@9 1130 * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
alpar@9 1131 * - BINARY otherwise.
alpar@9 1132 * - The following partially-portable control characters form a
alpar@9 1133 * "gray list" that is ignored in this detection algorithm:
alpar@9 1134 * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
alpar@9 1135 * IN assertion: the fields Freq of dyn_ltree are set.
alpar@9 1136 */
alpar@9 1137 local int detect_data_type(s)
alpar@9 1138 deflate_state *s;
alpar@9 1139 {
alpar@9 1140 /* black_mask is the bit mask of black-listed bytes
alpar@9 1141 * set bits 0..6, 14..25, and 28..31
alpar@9 1142 * 0xf3ffc07f = binary 11110011111111111100000001111111
alpar@9 1143 */
alpar@9 1144 unsigned long black_mask = 0xf3ffc07fUL;
alpar@9 1145 int n;
alpar@9 1146
alpar@9 1147 /* Check for non-textual ("black-listed") bytes. */
alpar@9 1148 for (n = 0; n <= 31; n++, black_mask >>= 1)
alpar@9 1149 if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
alpar@9 1150 return Z_BINARY;
alpar@9 1151
alpar@9 1152 /* Check for textual ("white-listed") bytes. */
alpar@9 1153 if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
alpar@9 1154 || s->dyn_ltree[13].Freq != 0)
alpar@9 1155 return Z_TEXT;
alpar@9 1156 for (n = 32; n < LITERALS; n++)
alpar@9 1157 if (s->dyn_ltree[n].Freq != 0)
alpar@9 1158 return Z_TEXT;
alpar@9 1159
alpar@9 1160 /* There are no "black-listed" or "white-listed" bytes:
alpar@9 1161 * this stream either is empty or has tolerated ("gray-listed") bytes only.
alpar@9 1162 */
alpar@9 1163 return Z_BINARY;
alpar@9 1164 }
alpar@9 1165
alpar@9 1166 /* ===========================================================================
alpar@9 1167 * Reverse the first len bits of a code, using straightforward code (a faster
alpar@9 1168 * method would use a table)
alpar@9 1169 * IN assertion: 1 <= len <= 15
alpar@9 1170 */
alpar@9 1171 local unsigned bi_reverse(code, len)
alpar@9 1172 unsigned code; /* the value to invert */
alpar@9 1173 int len; /* its bit length */
alpar@9 1174 {
alpar@9 1175 register unsigned res = 0;
alpar@9 1176 do {
alpar@9 1177 res |= code & 1;
alpar@9 1178 code >>= 1, res <<= 1;
alpar@9 1179 } while (--len > 0);
alpar@9 1180 return res >> 1;
alpar@9 1181 }
alpar@9 1182
alpar@9 1183 /* ===========================================================================
alpar@9 1184 * Flush the bit buffer, keeping at most 7 bits in it.
alpar@9 1185 */
alpar@9 1186 local void bi_flush(s)
alpar@9 1187 deflate_state *s;
alpar@9 1188 {
alpar@9 1189 if (s->bi_valid == 16) {
alpar@9 1190 put_short(s, s->bi_buf);
alpar@9 1191 s->bi_buf = 0;
alpar@9 1192 s->bi_valid = 0;
alpar@9 1193 } else if (s->bi_valid >= 8) {
alpar@9 1194 put_byte(s, (Byte)s->bi_buf);
alpar@9 1195 s->bi_buf >>= 8;
alpar@9 1196 s->bi_valid -= 8;
alpar@9 1197 }
alpar@9 1198 }
alpar@9 1199
alpar@9 1200 /* ===========================================================================
alpar@9 1201 * Flush the bit buffer and align the output on a byte boundary
alpar@9 1202 */
alpar@9 1203 local void bi_windup(s)
alpar@9 1204 deflate_state *s;
alpar@9 1205 {
alpar@9 1206 if (s->bi_valid > 8) {
alpar@9 1207 put_short(s, s->bi_buf);
alpar@9 1208 } else if (s->bi_valid > 0) {
alpar@9 1209 put_byte(s, (Byte)s->bi_buf);
alpar@9 1210 }
alpar@9 1211 s->bi_buf = 0;
alpar@9 1212 s->bi_valid = 0;
alpar@9 1213 #ifdef DEBUG
alpar@9 1214 s->bits_sent = (s->bits_sent+7) & ~7;
alpar@9 1215 #endif
alpar@9 1216 }
alpar@9 1217
alpar@9 1218 /* ===========================================================================
alpar@9 1219 * Copy a stored block, storing first the length and its
alpar@9 1220 * one's complement if requested.
alpar@9 1221 */
alpar@9 1222 local void copy_block(s, buf, len, header)
alpar@9 1223 deflate_state *s;
alpar@9 1224 charf *buf; /* the input data */
alpar@9 1225 unsigned len; /* its length */
alpar@9 1226 int header; /* true if block header must be written */
alpar@9 1227 {
alpar@9 1228 bi_windup(s); /* align on byte boundary */
alpar@9 1229 s->last_eob_len = 8; /* enough lookahead for inflate */
alpar@9 1230
alpar@9 1231 if (header) {
alpar@9 1232 put_short(s, (ush)len);
alpar@9 1233 put_short(s, (ush)~len);
alpar@9 1234 #ifdef DEBUG
alpar@9 1235 s->bits_sent += 2*16;
alpar@9 1236 #endif
alpar@9 1237 }
alpar@9 1238 #ifdef DEBUG
alpar@9 1239 s->bits_sent += (ulg)len<<3;
alpar@9 1240 #endif
alpar@9 1241 while (len--) {
alpar@9 1242 put_byte(s, *buf++);
alpar@9 1243 }
alpar@9 1244 }