trees.c revision 237410
1122394Sharti/* trees.c -- output deflated data using Huffman coding 2122394Sharti * Copyright (C) 1995-2012 Jean-loup Gailly 3122394Sharti * detect_data_type() function provided freely by Cosmin Truta, 2006 4122394Sharti * For conditions of distribution and use, see copyright notice in zlib.h 5122394Sharti */ 6159063Sharti 7133211Sharti/* 8133211Sharti * ALGORITHM 9133211Sharti * 10122394Sharti * The "deflation" process uses several Huffman trees. The more 11133211Sharti * common source values are represented by shorter bit sequences. 12133211Sharti * 13133211Sharti * Each code tree is stored in a compressed form which is itself 14133211Sharti * a Huffman encoding of the lengths of all the code strings (in 15133211Sharti * ascending order by source values). The actual code strings are 16133211Sharti * reconstructed from the lengths in the inflate process, as described 17122394Sharti * in the deflate specification. 18122394Sharti * 19122394Sharti * REFERENCES 20133211Sharti * 21133211Sharti * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". 22133211Sharti * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc 23133211Sharti * 24133211Sharti * Storer, James A. 25133211Sharti * Data Compression: Methods and Theory, pp. 49-50. 26133211Sharti * Computer Science Press, 1988. ISBN 0-7167-8156-5. 27133211Sharti * 28133211Sharti * Sedgewick, R. 29133211Sharti * Algorithms, p290. 30133211Sharti * Addison-Wesley, 1983. ISBN 0-201-06672-6. 31133211Sharti */ 32122394Sharti 33159063Sharti/* @(#) $Id$ */ 34122394Sharti 35122394Sharti/* #define GEN_TREES_H */ 36122394Sharti 37122394Sharti#include "deflate.h" 38122394Sharti 39159063Sharti#ifdef DEBUG 40133211Sharti# include <ctype.h> 41159063Sharti#endif 42159063Sharti 43122394Sharti/* =========================================================================== 44122394Sharti * Constants 45122394Sharti */ 46122394Sharti 47159063Sharti#define MAX_BL_BITS 7 48122394Sharti/* Bit length codes must not exceed MAX_BL_BITS bits */ 49159063Sharti 50122394Sharti#define END_BLOCK 256 51159063Sharti/* end of block literal code */ 52159063Sharti 53159063Sharti#define REP_3_6 16 54159063Sharti/* repeat previous bit length 3-6 times (2 bits of repeat count) */ 55159063Sharti 56159063Sharti#define REPZ_3_10 17 57159063Sharti/* repeat a zero length 3-10 times (3 bits of repeat count) */ 58159063Sharti 59159063Sharti#define REPZ_11_138 18 60159063Sharti/* repeat a zero length 11-138 times (7 bits of repeat count) */ 61159063Sharti 62159063Shartilocal const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ 63122394Sharti = {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}; 64122394Sharti 65122394Shartilocal const int extra_dbits[D_CODES] /* extra bits for each distance code */ 66122394Sharti = {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}; 67142810Sharti 68122394Shartilocal const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ 69159063Sharti = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; 70122394Sharti 71159063Shartilocal const uch bl_order[BL_CODES] 72159063Sharti = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; 73159063Sharti/* The lengths of the bit length codes are sent in order of decreasing 74159063Sharti * probability, to avoid transmitting the lengths for unused bit length codes. 75159063Sharti */ 76122394Sharti 77122394Sharti/* =========================================================================== 78122394Sharti * Local data. These are initialized only once. 79122394Sharti */ 80122394Sharti 81122394Sharti#define DIST_CODE_LEN 512 /* see definition of array dist_code below */ 82122394Sharti 83122394Sharti#if defined(GEN_TREES_H) || !defined(STDC) 84122394Sharti/* non ANSI compilers may not accept trees.h */ 85133429Sharti 86133211Shartilocal ct_data static_ltree[L_CODES+2]; 87133211Sharti/* The static literal tree. Since the bit lengths are imposed, there is no 88122394Sharti * need for the L_CODES extra codes used during heap construction. However 89133211Sharti * The codes 286 and 287 are needed to build a canonical tree (see _tr_init 90122394Sharti * below). 91133211Sharti */ 92122394Sharti 93122394Shartilocal ct_data static_dtree[D_CODES]; 94122394Sharti/* The static distance tree. (Actually a trivial tree since all codes use 95122394Sharti * 5 bits.) 96122394Sharti */ 97122394Sharti 98122394Shartiuch _dist_code[DIST_CODE_LEN]; 99122394Sharti/* Distance codes. The first 256 values correspond to the distances 100122394Sharti * 3 .. 258, the last 256 values correspond to the top 8 bits of 101122394Sharti * the 15 bit distances. 102122394Sharti */ 103122394Sharti 104122394Shartiuch _length_code[MAX_MATCH-MIN_MATCH+1]; 105122394Sharti/* length code for each normalized match length (0 == MIN_MATCH) */ 106122394Sharti 107122394Shartilocal int base_length[LENGTH_CODES]; 108159063Sharti/* First normalized length for each code (0 = MIN_MATCH) */ 109159063Sharti 110159063Shartilocal int base_dist[D_CODES]; 111122394Sharti/* First normalized distance for each code (0 = distance of 1) */ 112159063Sharti 113159063Sharti#else 114159063Sharti# include "trees.h" 115122394Sharti#endif /* GEN_TREES_H */ 116159063Sharti 117159063Shartistruct static_tree_desc_s { 118159063Sharti const ct_data *static_tree; /* static tree or NULL */ 119122394Sharti const intf *extra_bits; /* extra bits for each code or NULL */ 120159063Sharti int extra_base; /* base index for extra_bits */ 121159063Sharti int elems; /* max number of elements in the tree */ 122122394Sharti int max_length; /* max bit length for the codes */ 123122394Sharti}; 124159063Sharti 125122394Shartilocal static_tree_desc static_l_desc = 126122394Sharti{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; 127122394Sharti 128122394Shartilocal static_tree_desc static_d_desc = 129122394Sharti{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; 130122394Sharti 131122394Shartilocal static_tree_desc static_bl_desc = 132122394Sharti{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; 133122394Sharti 134122394Sharti/* =========================================================================== 135122394Sharti * Local (static) routines in this file. 136122394Sharti */ 137122394Sharti 138122394Shartilocal void tr_static_init OF((void)); 139122394Shartilocal void init_block OF((deflate_state *s)); 140122394Shartilocal void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); 141122394Shartilocal void gen_bitlen OF((deflate_state *s, tree_desc *desc)); 142122394Shartilocal void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); 143122394Shartilocal void build_tree OF((deflate_state *s, tree_desc *desc)); 144122394Shartilocal void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); 145122394Shartilocal void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); 146122394Shartilocal int build_bl_tree OF((deflate_state *s)); 147122394Shartilocal void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, 148122394Sharti int blcodes)); 149122394Shartilocal void compress_block OF((deflate_state *s, ct_data *ltree, 150122394Sharti ct_data *dtree)); 151122394Shartilocal int detect_data_type OF((deflate_state *s)); 152122394Shartilocal unsigned bi_reverse OF((unsigned value, int length)); 153122394Shartilocal void bi_windup OF((deflate_state *s)); 154122394Shartilocal void bi_flush OF((deflate_state *s)); 155122394Shartilocal void copy_block OF((deflate_state *s, charf *buf, unsigned len, 156122394Sharti int header)); 157122394Sharti 158122394Sharti#ifdef GEN_TREES_H 159133211Shartilocal void gen_trees_header OF((void)); 160122394Sharti#endif 161122394Sharti 162122394Sharti#ifndef DEBUG 163122394Sharti# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) 164122394Sharti /* Send a code of the given tree. c and tree must not have side effects */ 165122394Sharti 166122394Sharti#else /* DEBUG */ 167122394Sharti# define send_code(s, c, tree) \ 168122394Sharti { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ 169122394Sharti send_bits(s, tree[c].Code, tree[c].Len); } 170122394Sharti#endif 171122394Sharti 172122394Sharti/* =========================================================================== 173122394Sharti * Output a short LSB first on the stream. 174122394Sharti * IN assertion: there is enough room in pendingBuf. 175122394Sharti */ 176122394Sharti#define put_short(s, w) { \ 177122394Sharti put_byte(s, (uch)((w) & 0xff)); \ 178122394Sharti put_byte(s, (uch)((ush)(w) >> 8)); \ 179122394Sharti} 180122394Sharti 181122394Sharti/* =========================================================================== 182159063Sharti * Send a value on a given number of bits. 183159063Sharti * IN assertion: length <= 16 and value fits in length bits. 184159063Sharti */ 185159063Sharti#ifdef DEBUG 186159063Shartilocal void send_bits OF((deflate_state *s, int value, int length)); 187159063Sharti 188159063Shartilocal void send_bits(s, value, length) 189159063Sharti deflate_state *s; 190159063Sharti int value; /* value to send */ 191159063Sharti int length; /* number of bits */ 192159063Sharti{ 193159063Sharti Tracevv((stderr," l %2d v %4x ", length, value)); 194159063Sharti Assert(length > 0 && length <= 15, "invalid length"); 195159063Sharti s->bits_sent += (ulg)length; 196159063Sharti 197159063Sharti /* If not enough room in bi_buf, use (valid) bits from bi_buf and 198159063Sharti * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) 199159063Sharti * unused bits in value. 200159063Sharti */ 201159063Sharti if (s->bi_valid > (int)Buf_size - length) { 202159063Sharti s->bi_buf |= (ush)value << s->bi_valid; 203159063Sharti put_short(s, s->bi_buf); 204159063Sharti s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); 205122394Sharti s->bi_valid += length - Buf_size; 206122394Sharti } else { 207122394Sharti s->bi_buf |= (ush)value << s->bi_valid; 208122394Sharti s->bi_valid += length; 209122394Sharti } 210122394Sharti} 211122394Sharti#else /* !DEBUG */ 212122394Sharti 213122394Sharti#define send_bits(s, value, length) \ 214122394Sharti{ int len = length;\ 215145557Sharti if (s->bi_valid > (int)Buf_size - len) {\ 216122394Sharti int val = value;\ 217122394Sharti s->bi_buf |= (ush)val << s->bi_valid;\ 218122394Sharti put_short(s, s->bi_buf);\ 219122394Sharti s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ 220159063Sharti s->bi_valid += len - Buf_size;\ 221159063Sharti } else {\ 222159063Sharti s->bi_buf |= (ush)(value) << s->bi_valid;\ 223159063Sharti s->bi_valid += len;\ 224159063Sharti }\ 225159063Sharti} 226159063Sharti#endif /* DEBUG */ 227159063Sharti 228159063Sharti 229122394Sharti/* the arguments must not have side effects */ 230122394Sharti 231159063Sharti/* =========================================================================== 232159063Sharti * Initialize the various 'constant' tables. 233159063Sharti */ 234159063Shartilocal void tr_static_init() 235159063Sharti{ 236159063Sharti#if defined(GEN_TREES_H) || !defined(STDC) 237159063Sharti static int static_init_done = 0; 238159063Sharti int n; /* iterates over tree elements */ 239159063Sharti int bits; /* bit counter */ 240159063Sharti int length; /* length value */ 241159063Sharti int code; /* code value */ 242159063Sharti int dist; /* distance index */ 243159063Sharti ush bl_count[MAX_BITS+1]; 244159063Sharti /* number of codes at each bit length for an optimal tree */ 245159063Sharti 246159063Sharti if (static_init_done) return; 247159063Sharti 248159063Sharti /* For some embedded targets, global variables are not initialized: */ 249159063Sharti#ifdef NO_INIT_GLOBAL_POINTERS 250159063Sharti static_l_desc.static_tree = static_ltree; 251159063Sharti static_l_desc.extra_bits = extra_lbits; 252159063Sharti static_d_desc.static_tree = static_dtree; 253159063Sharti static_d_desc.extra_bits = extra_dbits; 254159063Sharti static_bl_desc.extra_bits = extra_blbits; 255159063Sharti#endif 256159063Sharti 257159063Sharti /* Initialize the mapping length (0..255) -> length code (0..28) */ 258159063Sharti length = 0; 259159063Sharti for (code = 0; code < LENGTH_CODES-1; code++) { 260159063Sharti base_length[code] = length; 261159063Sharti for (n = 0; n < (1<<extra_lbits[code]); n++) { 262159063Sharti _length_code[length++] = (uch)code; 263159063Sharti } 264159063Sharti } 265159063Sharti Assert (length == 256, "tr_static_init: length != 256"); 266159063Sharti /* Note that the length 255 (match length 258) can be represented 267159063Sharti * in two different ways: code 284 + 5 bits or code 285, so we 268159063Sharti * overwrite length_code[255] to use the best encoding: 269159063Sharti */ 270159063Sharti _length_code[length-1] = (uch)code; 271159063Sharti 272159063Sharti /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ 273159063Sharti dist = 0; 274159063Sharti for (code = 0 ; code < 16; code++) { 275159063Sharti base_dist[code] = dist; 276159063Sharti for (n = 0; n < (1<<extra_dbits[code]); n++) { 277159063Sharti _dist_code[dist++] = (uch)code; 278159063Sharti } 279159063Sharti } 280159063Sharti Assert (dist == 256, "tr_static_init: dist != 256"); 281159063Sharti dist >>= 7; /* from now on, all distances are divided by 128 */ 282159063Sharti for ( ; code < D_CODES; code++) { 283159063Sharti base_dist[code] = dist << 7; 284159063Sharti for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { 285159063Sharti _dist_code[256 + dist++] = (uch)code; 286159063Sharti } 287159063Sharti } 288159063Sharti Assert (dist == 256, "tr_static_init: 256+dist != 512"); 289159063Sharti 290159063Sharti /* Construct the codes of the static literal tree */ 291159063Sharti for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; 292159063Sharti n = 0; 293159063Sharti while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; 294159063Sharti while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; 295159063Sharti while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; 296159063Sharti while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; 297159063Sharti /* Codes 286 and 287 do not exist, but we must include them in the 298159063Sharti * tree construction to get a canonical Huffman tree (longest code 299159063Sharti * all ones) 300159063Sharti */ 301159063Sharti gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); 302159063Sharti 303159063Sharti /* The static distance tree is trivial: */ 304159063Sharti for (n = 0; n < D_CODES; n++) { 305159063Sharti static_dtree[n].Len = 5; 306159063Sharti static_dtree[n].Code = bi_reverse((unsigned)n, 5); 307159063Sharti } 308159063Sharti static_init_done = 1; 309159063Sharti 310159063Sharti# ifdef GEN_TREES_H 311159063Sharti gen_trees_header(); 312159063Sharti# endif 313159063Sharti#endif /* defined(GEN_TREES_H) || !defined(STDC) */ 314159063Sharti} 315159063Sharti 316159063Sharti/* =========================================================================== 317159063Sharti * Genererate the file trees.h describing the static trees. 318159063Sharti */ 319159063Sharti#ifdef GEN_TREES_H 320159063Sharti# ifndef DEBUG 321159063Sharti# include <stdio.h> 322159063Sharti# endif 323159063Sharti 324159063Sharti# define SEPARATOR(i, last, width) \ 325159063Sharti ((i) == (last)? "\n};\n\n" : \ 326159063Sharti ((i) % (width) == (width)-1 ? ",\n" : ", ")) 327159063Sharti 328159063Shartivoid gen_trees_header() 329159063Sharti{ 330159063Sharti FILE *header = fopen("trees.h", "w"); 331159063Sharti int i; 332159063Sharti 333159063Sharti Assert (header != NULL, "Can't open trees.h"); 334159063Sharti fprintf(header, 335159063Sharti "/* header created automatically with -DGEN_TREES_H */\n\n"); 336159063Sharti 337159063Sharti fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); 338159063Sharti for (i = 0; i < L_CODES+2; i++) { 339159063Sharti fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, 340159063Sharti static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); 341159063Sharti } 342159063Sharti 343159063Sharti fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); 344159063Sharti for (i = 0; i < D_CODES; i++) { 345159063Sharti fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, 346159063Sharti static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); 347159063Sharti } 348159063Sharti 349159063Sharti fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n"); 350159063Sharti for (i = 0; i < DIST_CODE_LEN; i++) { 351159063Sharti fprintf(header, "%2u%s", _dist_code[i], 352159063Sharti SEPARATOR(i, DIST_CODE_LEN-1, 20)); 353159063Sharti } 354159063Sharti 355159063Sharti fprintf(header, 356159063Sharti "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); 357159063Sharti for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { 358159063Sharti fprintf(header, "%2u%s", _length_code[i], 359159063Sharti SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); 360159063Sharti } 361159063Sharti 362159063Sharti fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); 363159063Sharti for (i = 0; i < LENGTH_CODES; i++) { 364159063Sharti fprintf(header, "%1u%s", base_length[i], 365159063Sharti SEPARATOR(i, LENGTH_CODES-1, 20)); 366159063Sharti } 367159063Sharti 368159063Sharti fprintf(header, "local const int base_dist[D_CODES] = {\n"); 369159063Sharti for (i = 0; i < D_CODES; i++) { 370159063Sharti fprintf(header, "%5u%s", base_dist[i], 371159063Sharti SEPARATOR(i, D_CODES-1, 10)); 372159063Sharti } 373159063Sharti 374159063Sharti fclose(header); 375159063Sharti} 376159063Sharti#endif /* GEN_TREES_H */ 377159063Sharti 378159063Sharti/* =========================================================================== 379159063Sharti * Initialize the tree data structures for a new zlib stream. 380122394Sharti */ 381122394Shartivoid ZLIB_INTERNAL _tr_init(s) 382122394Sharti deflate_state *s; 383122394Sharti{ 384122394Sharti tr_static_init(); 385122394Sharti 386122394Sharti s->l_desc.dyn_tree = s->dyn_ltree; 387122394Sharti s->l_desc.stat_desc = &static_l_desc; 388159063Sharti 389159063Sharti s->d_desc.dyn_tree = s->dyn_dtree; 390159063Sharti s->d_desc.stat_desc = &static_d_desc; 391159063Sharti 392159063Sharti s->bl_desc.dyn_tree = s->bl_tree; 393159063Sharti s->bl_desc.stat_desc = &static_bl_desc; 394122394Sharti 395122394Sharti s->bi_buf = 0; 396122394Sharti s->bi_valid = 0; 397122394Sharti#ifdef DEBUG 398122394Sharti s->compressed_len = 0L; 399122394Sharti s->bits_sent = 0L; 400122394Sharti#endif 401122394Sharti 402122394Sharti /* Initialize the first block of the first file: */ 403122394Sharti init_block(s); 404122394Sharti} 405122394Sharti 406122394Sharti/* =========================================================================== 407122394Sharti * Initialize a new block. 408122394Sharti */ 409122394Shartilocal void init_block(s) 410122394Sharti deflate_state *s; 411122394Sharti{ 412122394Sharti int n; /* iterates over tree elements */ 413122394Sharti 414159063Sharti /* Initialize the trees. */ 415159063Sharti for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; 416159063Sharti for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; 417159063Sharti for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; 418122394Sharti 419122394Sharti s->dyn_ltree[END_BLOCK].Freq = 1; 420122394Sharti s->opt_len = s->static_len = 0L; 421122394Sharti s->last_lit = s->matches = 0; 422122394Sharti} 423122394Sharti 424122394Sharti#define SMALLEST 1 425133211Sharti/* Index within the heap array of least frequent node in the Huffman tree */ 426159063Sharti 427122394Sharti 428122394Sharti/* =========================================================================== 429122394Sharti * Remove the smallest element from the heap and recreate the heap with 430122394Sharti * one less element. Updates heap and heap_len. 431122394Sharti */ 432122394Sharti#define pqremove(s, tree, top) \ 433122394Sharti{\ 434122394Sharti top = s->heap[SMALLEST]; \ 435122394Sharti s->heap[SMALLEST] = s->heap[s->heap_len--]; \ 436122394Sharti pqdownheap(s, tree, SMALLEST); \ 437122394Sharti} 438159063Sharti 439122394Sharti/* =========================================================================== 440122394Sharti * Compares to subtrees, using the tree depth as tie breaker when 441122394Sharti * the subtrees have equal frequency. This minimizes the worst case length. 442159063Sharti */ 443122394Sharti#define smaller(tree, n, m, depth) \ 444122394Sharti (tree[n].Freq < tree[m].Freq || \ 445122394Sharti (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) 446122394Sharti 447122394Sharti/* =========================================================================== 448122394Sharti * Restore the heap property by moving down the tree starting at node k, 449122394Sharti * exchanging a node with the smallest of its two sons if necessary, stopping 450122394Sharti * when the heap property is re-established (each father smaller than its 451122394Sharti * two sons). 452122394Sharti */ 453122394Shartilocal void pqdownheap(s, tree, k) 454122394Sharti deflate_state *s; 455122394Sharti ct_data *tree; /* the tree to restore */ 456122394Sharti int k; /* node to move down */ 457122394Sharti{ 458122394Sharti int v = s->heap[k]; 459122394Sharti int j = k << 1; /* left son of k */ 460122394Sharti while (j <= s->heap_len) { 461122394Sharti /* Set j to the smallest of the two sons: */ 462122394Sharti if (j < s->heap_len && 463122394Sharti smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { 464122394Sharti j++; 465122394Sharti } 466122394Sharti /* Exit if v is smaller than both sons */ 467159063Sharti if (smaller(tree, v, s->heap[j], s->depth)) break; 468122394Sharti 469122394Sharti /* Exchange v with the smallest son */ 470122394Sharti s->heap[k] = s->heap[j]; k = j; 471122394Sharti 472122394Sharti /* And continue down the tree, setting j to the left son of k */ 473122394Sharti j <<= 1; 474159063Sharti } 475122394Sharti s->heap[k] = v; 476122394Sharti} 477159063Sharti 478122394Sharti/* =========================================================================== 479159063Sharti * Compute the optimal bit lengths for a tree and update the total bit length 480159063Sharti * for the current block. 481159063Sharti * IN assertion: the fields freq and dad are set, heap[heap_max] and 482159063Sharti * above are the tree nodes sorted by increasing frequency. 483159063Sharti * OUT assertions: the field len is set to the optimal bit length, the 484159063Sharti * array bl_count contains the frequencies for each bit length. 485122394Sharti * The length opt_len is updated; static_len is also updated if stree is 486122394Sharti * not null. 487122394Sharti */ 488122394Shartilocal void gen_bitlen(s, desc) 489159063Sharti deflate_state *s; 490122394Sharti tree_desc *desc; /* the tree descriptor */ 491159063Sharti{ 492122394Sharti ct_data *tree = desc->dyn_tree; 493122394Sharti int max_code = desc->max_code; 494122394Sharti const ct_data *stree = desc->stat_desc->static_tree; 495122394Sharti const intf *extra = desc->stat_desc->extra_bits; 496122394Sharti int base = desc->stat_desc->extra_base; 497122394Sharti int max_length = desc->stat_desc->max_length; 498122394Sharti int h; /* heap index */ 499122394Sharti int n, m; /* iterate over the tree elements */ 500122394Sharti int bits; /* bit length */ 501122394Sharti int xbits; /* extra bits */ 502122394Sharti ush f; /* frequency */ 503122394Sharti int overflow = 0; /* number of elements with bit length too large */ 504159063Sharti 505122394Sharti for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; 506159063Sharti 507122394Sharti /* In a first pass, compute the optimal bit lengths (which may 508122394Sharti * overflow in the case of the bit length tree). 509122394Sharti */ 510122394Sharti tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ 511122394Sharti 512122394Sharti for (h = s->heap_max+1; h < HEAP_SIZE; h++) { 513122394Sharti n = s->heap[h]; 514122394Sharti bits = tree[tree[n].Dad].Len + 1; 515122394Sharti if (bits > max_length) bits = max_length, overflow++; 516159063Sharti tree[n].Len = (ush)bits; 517122394Sharti /* We overwrite tree[n].Dad which is no longer needed */ 518122394Sharti 519159063Sharti if (n > max_code) continue; /* not a leaf node */ 520159063Sharti 521159063Sharti s->bl_count[bits]++; 522159063Sharti xbits = 0; 523159063Sharti if (n >= base) xbits = extra[n-base]; 524159063Sharti f = tree[n].Freq; 525159063Sharti s->opt_len += (ulg)f * (bits + xbits); 526159063Sharti if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); 527159063Sharti } 528159063Sharti if (overflow == 0) return; 529159063Sharti 530159063Sharti Trace((stderr,"\nbit length overflow\n")); 531159063Sharti /* This happens for example on obj2 and pic of the Calgary corpus */ 532159063Sharti 533159063Sharti /* Find the first bit length which could increase: */ 534159063Sharti do { 535159063Sharti bits = max_length-1; 536159063Sharti while (s->bl_count[bits] == 0) bits--; 537159063Sharti s->bl_count[bits]--; /* move one leaf down the tree */ 538159063Sharti s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ 539159063Sharti s->bl_count[max_length]--; 540159063Sharti /* The brother of the overflow item also moves one step up, 541159063Sharti * but this does not affect bl_count[max_length] 542122394Sharti */ 543122394Sharti overflow -= 2; 544122394Sharti } while (overflow > 0); 545122394Sharti 546159063Sharti /* Now recompute all bit lengths, scanning in increasing frequency. 547159063Sharti * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all 548159063Sharti * lengths instead of fixing only the wrong ones. This idea is taken 549159063Sharti * from 'ar' written by Haruhiko Okumura.) 550159063Sharti */ 551159063Sharti for (bits = max_length; bits != 0; bits--) { 552159063Sharti n = s->bl_count[bits]; 553159063Sharti while (n != 0) { 554159063Sharti m = s->heap[--h]; 555159063Sharti if (m > max_code) continue; 556159063Sharti if ((unsigned) tree[m].Len != (unsigned) bits) { 557159063Sharti Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); 558159063Sharti s->opt_len += ((long)bits - (long)tree[m].Len) 559159063Sharti *(long)tree[m].Freq; 560159063Sharti tree[m].Len = (ush)bits; 561122394Sharti } 562122394Sharti n--; 563122394Sharti } 564122394Sharti } 565122394Sharti} 566122394Sharti 567122394Sharti/* =========================================================================== 568122394Sharti * Generate the codes for a given tree and bit counts (which need not be 569122394Sharti * optimal). 570159063Sharti * IN assertion: the array bl_count contains the bit length statistics for 571159063Sharti * the given tree and the field len is set for all tree elements. 572159063Sharti * OUT assertion: the field code is set for all tree elements of non 573122394Sharti * zero code length. 574122394Sharti */ 575122394Shartilocal void gen_codes (tree, max_code, bl_count) 576122394Sharti ct_data *tree; /* the tree to decorate */ 577122394Sharti int max_code; /* largest code with non zero frequency */ 578122394Sharti ushf *bl_count; /* number of codes at each bit length */ 579122394Sharti{ 580122394Sharti ush next_code[MAX_BITS+1]; /* next code value for each bit length */ 581122394Sharti ush code = 0; /* running code value */ 582122394Sharti int bits; /* bit index */ 583122394Sharti int n; /* code index */ 584122394Sharti 585122394Sharti /* The distribution counts are first used to generate the code values 586122394Sharti * without bit reversal. 587122394Sharti */ 588122394Sharti for (bits = 1; bits <= MAX_BITS; bits++) { 589122394Sharti next_code[bits] = code = (code + bl_count[bits-1]) << 1; 590122394Sharti } 591122394Sharti /* Check that the bit counts in bl_count are consistent. The last code 592159063Sharti * must be all ones. 593159063Sharti */ 594159063Sharti Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, 595159063Sharti "inconsistent bit counts"); 596159063Sharti Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); 597159063Sharti 598122394Sharti for (n = 0; n <= max_code; n++) { 599122394Sharti int len = tree[n].Len; 600122394Sharti if (len == 0) continue; 601159063Sharti /* Now reverse the bits */ 602122394Sharti tree[n].Code = bi_reverse(next_code[len]++, len); 603159063Sharti 604159063Sharti Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", 605122394Sharti n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); 606159063Sharti } 607159063Sharti} 608159063Sharti 609159063Sharti/* =========================================================================== 610122394Sharti * Construct one Huffman tree and assigns the code bit strings and lengths. 611159063Sharti * Update the total bit length for the current block. 612159063Sharti * IN assertion: the field freq is set for all tree elements. 613159063Sharti * OUT assertions: the fields len and code are set to the optimal bit length 614159063Sharti * and corresponding code. The length opt_len is updated; static_len is 615159063Sharti * also updated if stree is not null. The field max_code is set. 616159063Sharti */ 617159063Shartilocal void build_tree(s, desc) 618159063Sharti deflate_state *s; 619159063Sharti tree_desc *desc; /* the tree descriptor */ 620159063Sharti{ 621159063Sharti ct_data *tree = desc->dyn_tree; 622159063Sharti const ct_data *stree = desc->stat_desc->static_tree; 623159063Sharti int elems = desc->stat_desc->elems; 624159063Sharti int n, m; /* iterate over heap elements */ 625159063Sharti int max_code = -1; /* largest code with non zero frequency */ 626159063Sharti int node; /* new node being created */ 627159063Sharti 628159063Sharti /* Construct the initial heap, with least frequent element in 629159063Sharti * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. 630159063Sharti * heap[0] is not used. 631159063Sharti */ 632159063Sharti s->heap_len = 0, s->heap_max = HEAP_SIZE; 633159063Sharti 634159063Sharti for (n = 0; n < elems; n++) { 635159063Sharti if (tree[n].Freq != 0) { 636159063Sharti s->heap[++(s->heap_len)] = max_code = n; 637159063Sharti s->depth[n] = 0; 638159063Sharti } else { 639159063Sharti tree[n].Len = 0; 640159063Sharti } 641159063Sharti } 642159063Sharti 643159063Sharti /* The pkzip format requires that at least one distance code exists, 644159063Sharti * and that at least one bit should be sent even if there is only one 645159063Sharti * possible code. So to avoid special checks later on we force at least 646159063Sharti * two codes of non zero frequency. 647159063Sharti */ 648159063Sharti while (s->heap_len < 2) { 649159063Sharti node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); 650159063Sharti tree[node].Freq = 1; 651159063Sharti s->depth[node] = 0; 652159063Sharti s->opt_len--; if (stree) s->static_len -= stree[node].Len; 653159063Sharti /* node is 0 or 1 so it does not have extra bits */ 654159063Sharti } 655159063Sharti desc->max_code = max_code; 656159063Sharti 657159063Sharti /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, 658159063Sharti * establish sub-heaps of increasing lengths: 659159063Sharti */ 660159063Sharti for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); 661159063Sharti 662159063Sharti /* Construct the Huffman tree by repeatedly combining the least two 663159063Sharti * frequent nodes. 664159063Sharti */ 665159063Sharti node = elems; /* next internal node of the tree */ 666159063Sharti do { 667159063Sharti pqremove(s, tree, n); /* n = node of least frequency */ 668159063Sharti m = s->heap[SMALLEST]; /* m = node of next least frequency */ 669159063Sharti 670159063Sharti s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ 671159063Sharti s->heap[--(s->heap_max)] = m; 672159063Sharti 673159063Sharti /* Create a new node father of n and m */ 674159063Sharti tree[node].Freq = tree[n].Freq + tree[m].Freq; 675159063Sharti s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? 676159063Sharti s->depth[n] : s->depth[m]) + 1); 677159063Sharti tree[n].Dad = tree[m].Dad = (ush)node; 678159063Sharti#ifdef DUMP_BL_TREE 679159063Sharti if (tree == s->bl_tree) { 680159063Sharti fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", 681159063Sharti node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); 682159063Sharti } 683159063Sharti#endif 684159063Sharti /* and insert the new node in the heap */ 685159063Sharti s->heap[SMALLEST] = node++; 686122394Sharti pqdownheap(s, tree, SMALLEST); 687159063Sharti 688159063Sharti } while (s->heap_len >= 2); 689159063Sharti 690159063Sharti s->heap[--(s->heap_max)] = s->heap[SMALLEST]; 691159063Sharti 692159063Sharti /* At this point, the fields freq and dad are set. We can now 693159063Sharti * generate the bit lengths. 694159063Sharti */ 695159063Sharti gen_bitlen(s, (tree_desc *)desc); 696159063Sharti 697159063Sharti /* The field len is now set, we can generate the bit codes */ 698159063Sharti gen_codes ((ct_data *)tree, max_code, s->bl_count); 699159063Sharti} 700159063Sharti 701159063Sharti/* =========================================================================== 702159063Sharti * Scan a literal or distance tree to determine the frequencies of the codes 703159063Sharti * in the bit length tree. 704159063Sharti */ 705159063Shartilocal void scan_tree (s, tree, max_code) 706159063Sharti deflate_state *s; 707159063Sharti ct_data *tree; /* the tree to be scanned */ 708159063Sharti int max_code; /* and its largest code of non zero frequency */ 709159063Sharti{ 710159063Sharti int n; /* iterates over all tree elements */ 711159063Sharti int prevlen = -1; /* last emitted length */ 712159063Sharti int curlen; /* length of current code */ 713159063Sharti int nextlen = tree[0].Len; /* length of next code */ 714159063Sharti int count = 0; /* repeat count of the current code */ 715159063Sharti int max_count = 7; /* max repeat count */ 716159063Sharti int min_count = 4; /* min repeat count */ 717159063Sharti 718159063Sharti if (nextlen == 0) max_count = 138, min_count = 3; 719159063Sharti tree[max_code+1].Len = (ush)0xffff; /* guard */ 720159063Sharti 721159063Sharti for (n = 0; n <= max_code; n++) { 722159063Sharti curlen = nextlen; nextlen = tree[n+1].Len; 723159063Sharti if (++count < max_count && curlen == nextlen) { 724159063Sharti continue; 725159063Sharti } else if (count < min_count) { 726159063Sharti s->bl_tree[curlen].Freq += count; 727159063Sharti } else if (curlen != 0) { 728159063Sharti if (curlen != prevlen) s->bl_tree[curlen].Freq++; 729159063Sharti s->bl_tree[REP_3_6].Freq++; 730159063Sharti } else if (count <= 10) { 731159063Sharti s->bl_tree[REPZ_3_10].Freq++; 732159063Sharti } else { 733159063Sharti s->bl_tree[REPZ_11_138].Freq++; 734159063Sharti } 735159063Sharti count = 0; prevlen = curlen; 736159063Sharti if (nextlen == 0) { 737159063Sharti max_count = 138, min_count = 3; 738159063Sharti } else if (curlen == nextlen) { 739159063Sharti max_count = 6, min_count = 3; 740159063Sharti } else { 741159063Sharti max_count = 7, min_count = 4; 742159063Sharti } 743159063Sharti } 744159063Sharti} 745159063Sharti 746298450Sngie/* =========================================================================== 747298450Sngie * Send a literal or distance tree in compressed form, using the codes in 748159063Sharti * bl_tree. 749159063Sharti */ 750159063Shartilocal void send_tree (s, tree, max_code) 751159063Sharti deflate_state *s; 752159063Sharti ct_data *tree; /* the tree to be scanned */ 753159063Sharti int max_code; /* and its largest code of non zero frequency */ 754159063Sharti{ 755159063Sharti int n; /* iterates over all tree elements */ 756159063Sharti int prevlen = -1; /* last emitted length */ 757159063Sharti int curlen; /* length of current code */ 758159063Sharti int nextlen = tree[0].Len; /* length of next code */ 759159063Sharti int count = 0; /* repeat count of the current code */ 760159063Sharti int max_count = 7; /* max repeat count */ 761159063Sharti int min_count = 4; /* min repeat count */ 762159063Sharti 763159063Sharti /* tree[max_code+1].Len = -1; */ /* guard already set */ 764159063Sharti if (nextlen == 0) max_count = 138, min_count = 3; 765159063Sharti 766159063Sharti for (n = 0; n <= max_code; n++) { 767159063Sharti curlen = nextlen; nextlen = tree[n+1].Len; 768122394Sharti if (++count < max_count && curlen == nextlen) { 769122394Sharti continue; 770122394Sharti } else if (count < min_count) { 771122394Sharti do { send_code(s, curlen, s->bl_tree); } while (--count != 0); 772122394Sharti 773122394Sharti } else if (curlen != 0) { 774122394Sharti if (curlen != prevlen) { 775122394Sharti send_code(s, curlen, s->bl_tree); count--; 776122394Sharti } 777122394Sharti Assert(count >= 3 && count <= 6, " 3_6?"); 778159063Sharti send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); 779154182Sharti 780122394Sharti } else if (count <= 10) { 781122394Sharti send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); 782122394Sharti 783122394Sharti } else { 784122394Sharti send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); 785122394Sharti } 786122394Sharti count = 0; prevlen = curlen; 787122394Sharti if (nextlen == 0) { 788122394Sharti max_count = 138, min_count = 3; 789122394Sharti } else if (curlen == nextlen) { 790122394Sharti max_count = 6, min_count = 3; 791122394Sharti } else { 792159063Sharti max_count = 7, min_count = 4; 793159063Sharti } 794122394Sharti } 795159063Sharti} 796122394Sharti 797159063Sharti/* =========================================================================== 798122394Sharti * Construct the Huffman tree for the bit lengths and return the index in 799122394Sharti * bl_order of the last bit length code to send. 800122394Sharti */ 801122394Shartilocal int build_bl_tree(s) 802122394Sharti deflate_state *s; 803122394Sharti{ 804122394Sharti int max_blindex; /* index of last bit length code of non zero freq */ 805122394Sharti 806122394Sharti /* Determine the bit length frequencies for literal and distance trees */ 807122394Sharti scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); 808122394Sharti scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); 809122394Sharti 810122394Sharti /* Build the bit length tree: */ 811122394Sharti build_tree(s, (tree_desc *)(&(s->bl_desc))); 812122394Sharti /* opt_len now includes the length of the tree representations, except 813122394Sharti * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. 814122394Sharti */ 815122394Sharti 816122394Sharti /* Determine the number of bit length codes to send. The pkzip format 817122394Sharti * requires that at least 4 bit length codes be sent. (appnote.txt says 818122394Sharti * 3 but the actual value used is 4.) 819122394Sharti */ 820122394Sharti for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { 821122394Sharti if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; 822122394Sharti } 823159063Sharti /* Update opt_len to include the bit length tree and counts */ 824159063Sharti s->opt_len += 3*(max_blindex+1) + 5+5+4; 825159063Sharti Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", 826159063Sharti s->opt_len, s->static_len)); 827122394Sharti 828122394Sharti return max_blindex; 829122394Sharti} 830159063Sharti 831122394Sharti/* =========================================================================== 832122394Sharti * Send the header for a block using dynamic Huffman trees: the counts, the 833122394Sharti * lengths of the bit length codes, the literal tree and the distance tree. 834122394Sharti * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. 835122394Sharti */ 836122394Shartilocal void send_all_trees(s, lcodes, dcodes, blcodes) 837122394Sharti deflate_state *s; 838122394Sharti int lcodes, dcodes, blcodes; /* number of codes for each tree */ 839122394Sharti{ 840122394Sharti int rank; /* index in bl_order */ 841122394Sharti 842122394Sharti Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); 843122394Sharti Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, 844122394Sharti "too many codes"); 845122394Sharti Tracev((stderr, "\nbl counts: ")); 846122394Sharti send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ 847122394Sharti send_bits(s, dcodes-1, 5); 848122394Sharti send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ 849122394Sharti for (rank = 0; rank < blcodes; rank++) { 850122394Sharti Tracev((stderr, "\nbl code %2d ", bl_order[rank])); 851122394Sharti send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); 852122394Sharti } 853122394Sharti Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); 854122394Sharti 855122394Sharti send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ 856122394Sharti Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); 857122394Sharti 858122394Sharti send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ 859122394Sharti Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); 860122394Sharti} 861122394Sharti 862122394Sharti/* =========================================================================== 863159063Sharti * Send a stored block 864159063Sharti */ 865159063Shartivoid ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last) 866159063Sharti deflate_state *s; 867159063Sharti charf *buf; /* input block */ 868159063Sharti ulg stored_len; /* length of input block */ 869159063Sharti int last; /* one if this is the last block for a file */ 870159063Sharti{ 871159063Sharti send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */ 872159063Sharti#ifdef DEBUG 873159063Sharti s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; 874159063Sharti s->compressed_len += (stored_len + 4) << 3; 875159063Sharti#endif 876159063Sharti copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ 877159063Sharti} 878159063Sharti 879159063Sharti/* =========================================================================== 880159063Sharti * Flush the bits in the bit buffer to pending output (leaves at most 7 bits) 881159063Sharti */ 882159063Shartivoid ZLIB_INTERNAL _tr_flush_bits(s) 883159063Sharti deflate_state *s; 884159063Sharti{ 885159063Sharti bi_flush(s); 886159063Sharti} 887159063Sharti 888159063Sharti/* =========================================================================== 889159063Sharti * Send one empty static block to give enough lookahead for inflate. 890159063Sharti * This takes 10 bits, of which 7 may remain in the bit buffer. 891159063Sharti */ 892159063Shartivoid ZLIB_INTERNAL _tr_align(s) 893159063Sharti deflate_state *s; 894159063Sharti{ 895159063Sharti send_bits(s, STATIC_TREES<<1, 3); 896159063Sharti send_code(s, END_BLOCK, static_ltree); 897159063Sharti#ifdef DEBUG 898159063Sharti s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ 899159063Sharti#endif 900159063Sharti bi_flush(s); 901122394Sharti} 902122394Sharti 903122394Sharti/* =========================================================================== 904159063Sharti * Determine the best encoding for the current block: dynamic trees, static 905159063Sharti * trees or store, and output the encoded block to the zip file. 906122394Sharti */ 907122394Shartivoid ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) 908122394Sharti deflate_state *s; 909122394Sharti charf *buf; /* input block, or NULL if too old */ 910122394Sharti ulg stored_len; /* length of input block */ 911122394Sharti int last; /* one if this is the last block for a file */ 912122394Sharti{ 913122394Sharti ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ 914122394Sharti int max_blindex = 0; /* index of last bit length code of non zero freq */ 915122394Sharti 916122394Sharti /* Build the Huffman trees unless a stored block is forced */ 917159063Sharti if (s->level > 0) { 918122394Sharti 919122394Sharti /* Check if the file is binary or text */ 920122394Sharti if (s->strm->data_type == Z_UNKNOWN) 921122394Sharti s->strm->data_type = detect_data_type(s); 922122394Sharti 923159063Sharti /* Construct the literal and distance trees */ 924159063Sharti build_tree(s, (tree_desc *)(&(s->l_desc))); 925122394Sharti Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, 926122394Sharti s->static_len)); 927122394Sharti 928122394Sharti build_tree(s, (tree_desc *)(&(s->d_desc))); 929122394Sharti Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, 930122394Sharti s->static_len)); 931122394Sharti /* At this point, opt_len and static_len are the total bit lengths of 932122394Sharti * the compressed block data, excluding the tree representations. 933122394Sharti */ 934122394Sharti 935122394Sharti /* Build the bit length tree for the above two trees, and get the index 936122394Sharti * in bl_order of the last bit length code to send. 937122394Sharti */ 938122394Sharti max_blindex = build_bl_tree(s); 939122394Sharti 940122394Sharti /* Determine the best encoding. Compute the block lengths in bytes. */ 941122394Sharti opt_lenb = (s->opt_len+3+7)>>3; 942122394Sharti static_lenb = (s->static_len+3+7)>>3; 943122394Sharti 944122394Sharti Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", 945122394Sharti opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, 946122394Sharti s->last_lit)); 947122394Sharti 948122394Sharti if (static_lenb <= opt_lenb) opt_lenb = static_lenb; 949122394Sharti 950122394Sharti } else { 951122394Sharti Assert(buf != (char*)0, "lost buf"); 952122394Sharti opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ 953122394Sharti } 954122394Sharti 955122394Sharti#ifdef FORCE_STORED 956122394Sharti if (buf != (char*)0) { /* force stored block */ 957122394Sharti#else 958122394Sharti if (stored_len+4 <= opt_lenb && buf != (char*)0) { 959122394Sharti /* 4: two words for the lengths */ 960122394Sharti#endif 961122394Sharti /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. 962122394Sharti * Otherwise we can't have processed more than WSIZE input bytes since 963122394Sharti * the last block flush, because compression would have been 964122394Sharti * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to 965122394Sharti * transform a block into a stored block. 966122394Sharti */ 967122394Sharti _tr_stored_block(s, buf, stored_len, last); 968122394Sharti 969122394Sharti#ifdef FORCE_STATIC 970122394Sharti } else if (static_lenb >= 0) { /* force static trees */ 971122394Sharti#else 972122394Sharti } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { 973122394Sharti#endif 974122394Sharti send_bits(s, (STATIC_TREES<<1)+last, 3); 975122394Sharti compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); 976122394Sharti#ifdef DEBUG 977122394Sharti s->compressed_len += 3 + s->static_len; 978122394Sharti#endif 979122394Sharti } else { 980122394Sharti send_bits(s, (DYN_TREES<<1)+last, 3); 981122394Sharti send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, 982122394Sharti max_blindex+1); 983122394Sharti compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); 984122394Sharti#ifdef DEBUG 985122394Sharti s->compressed_len += 3 + s->opt_len; 986122394Sharti#endif 987122394Sharti } 988122394Sharti Assert (s->compressed_len == s->bits_sent, "bad compressed size"); 989122394Sharti /* The above check is made mod 2^32, for files larger than 512 MB 990122394Sharti * and uLong implemented on 32 bits. 991122394Sharti */ 992122394Sharti init_block(s); 993122394Sharti 994122394Sharti if (last) { 995122394Sharti bi_windup(s); 996122394Sharti#ifdef DEBUG 997122394Sharti s->compressed_len += 7; /* align on byte boundary */ 998122394Sharti#endif 999122394Sharti } 1000128237Sharti Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, 1001122394Sharti s->compressed_len-7*last)); 1002122394Sharti} 1003122394Sharti 1004122394Sharti/* =========================================================================== 1005122394Sharti * Save the match info and tally the frequency counts. Return true if 1006122394Sharti * the current block must be flushed. 1007122394Sharti */ 1008122394Shartiint ZLIB_INTERNAL _tr_tally (s, dist, lc) 1009159063Sharti deflate_state *s; 1010122394Sharti unsigned dist; /* distance of matched string */ 1011122394Sharti unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ 1012122394Sharti{ 1013122394Sharti s->d_buf[s->last_lit] = (ush)dist; 1014122394Sharti s->l_buf[s->last_lit++] = (uch)lc; 1015122394Sharti if (dist == 0) { 1016122394Sharti /* lc is the unmatched char */ 1017122394Sharti s->dyn_ltree[lc].Freq++; 1018159063Sharti } else { 1019122394Sharti s->matches++; 1020122394Sharti /* Here, lc is the match length - MIN_MATCH */ 1021122394Sharti dist--; /* dist = match distance - 1 */ 1022122394Sharti Assert((ush)dist < (ush)MAX_DIST(s) && 1023159063Sharti (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && 1024122394Sharti (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); 1025122394Sharti 1026122394Sharti s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; 1027122394Sharti s->dyn_dtree[d_code(dist)].Freq++; 1028122394Sharti } 1029122394Sharti 1030142810Sharti#ifdef TRUNCATE_BLOCK 1031142810Sharti /* Try to guess if it is profitable to stop the current block here */ 1032142810Sharti if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { 1033142810Sharti /* Compute an upper bound for the compressed length */ 1034122394Sharti ulg out_length = (ulg)s->last_lit*8L; 1035142810Sharti ulg in_length = (ulg)((long)s->strstart - s->block_start); 1036122394Sharti int dcode; 1037122394Sharti for (dcode = 0; dcode < D_CODES; dcode++) { 1038122394Sharti out_length += (ulg)s->dyn_dtree[dcode].Freq * 1039122394Sharti (5L+extra_dbits[dcode]); 1040122394Sharti } 1041122394Sharti out_length >>= 3; 1042122394Sharti Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", 1043122394Sharti s->last_lit, in_length, out_length, 1044159063Sharti 100L - out_length*100L/in_length)); 1045122394Sharti if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; 1046122394Sharti } 1047122394Sharti#endif 1048122394Sharti return (s->last_lit == s->lit_bufsize-1); 1049122394Sharti /* We avoid equality with lit_bufsize because of wraparound at 64K 1050122394Sharti * on 16 bit machines and because stored blocks are restricted to 1051122394Sharti * 64K-1 bytes. 1052122394Sharti */ 1053122394Sharti} 1054122394Sharti 1055122394Sharti/* =========================================================================== 1056122394Sharti * Send the block data compressed using the given Huffman trees 1057122394Sharti */ 1058122394Shartilocal void compress_block(s, ltree, dtree) 1059159063Sharti deflate_state *s; 1060122394Sharti ct_data *ltree; /* literal tree */ 1061122394Sharti ct_data *dtree; /* distance tree */ 1062122394Sharti{ 1063122394Sharti unsigned dist; /* distance of matched string */ 1064122394Sharti int lc; /* match length or unmatched char (if dist == 0) */ 1065150920Sharti unsigned lx = 0; /* running index in l_buf */ 1066133211Sharti unsigned code; /* the code to send */ 1067150920Sharti int extra; /* number of extra bits to send */ 1068122394Sharti 1069122394Sharti if (s->last_lit != 0) do { 1070122394Sharti dist = s->d_buf[lx]; 1071122394Sharti lc = s->l_buf[lx++]; 1072122394Sharti if (dist == 0) { 1073122394Sharti send_code(s, lc, ltree); /* send a literal byte */ 1074122394Sharti Tracecv(isgraph(lc), (stderr," '%c' ", lc)); 1075122394Sharti } else { 1076122394Sharti /* Here, lc is the match length - MIN_MATCH */ 1077122394Sharti code = _length_code[lc]; 1078122394Sharti send_code(s, code+LITERALS+1, ltree); /* send the length code */ 1079122394Sharti extra = extra_lbits[code]; 1080122394Sharti if (extra != 0) { 1081122394Sharti lc -= base_length[code]; 1082122394Sharti send_bits(s, lc, extra); /* send the extra length bits */ 1083122394Sharti } 1084159063Sharti dist--; /* dist is now the match distance - 1 */ 1085122394Sharti code = d_code(dist); 1086122394Sharti Assert (code < D_CODES, "bad d_code"); 1087122394Sharti 1088122394Sharti send_code(s, code, dtree); /* send the distance code */ 1089133211Sharti extra = extra_dbits[code]; 1090133211Sharti if (extra != 0) { 1091133211Sharti dist -= base_dist[code]; 1092133211Sharti send_bits(s, dist, extra); /* send the extra distance bits */ 1093133211Sharti } 1094133211Sharti } /* literal or match pair ? */ 1095133211Sharti 1096133211Sharti /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ 1097133211Sharti Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, 1098133211Sharti "pendingBuf overflow"); 1099133211Sharti 1100133211Sharti } while (lx < s->last_lit); 1101133211Sharti 1102133211Sharti send_code(s, END_BLOCK, ltree); 1103133211Sharti} 1104133211Sharti 1105133211Sharti/* =========================================================================== 1106133211Sharti * Check if the data type is TEXT or BINARY, using the following algorithm: 1107133211Sharti * - TEXT if the two conditions below are satisfied: 1108133211Sharti * a) There are no non-portable control characters belonging to the 1109133211Sharti * "black list" (0..6, 14..25, 28..31). 1110133211Sharti * b) There is at least one printable character belonging to the 1111133211Sharti * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). 1112133211Sharti * - BINARY otherwise. 1113133211Sharti * - The following partially-portable control characters form a 1114133211Sharti * "gray list" that is ignored in this detection algorithm: 1115133211Sharti * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). 1116133211Sharti * IN assertion: the fields Freq of dyn_ltree are set. 1117133211Sharti */ 1118133211Shartilocal int detect_data_type(s) 1119133211Sharti deflate_state *s; 1120133211Sharti{ 1121133211Sharti /* black_mask is the bit mask of black-listed bytes 1122133211Sharti * set bits 0..6, 14..25, and 28..31 1123133211Sharti * 0xf3ffc07f = binary 11110011111111111100000001111111 1124133211Sharti */ 1125133211Sharti unsigned long black_mask = 0xf3ffc07fUL; 1126133211Sharti int n; 1127133211Sharti 1128133211Sharti /* Check for non-textual ("black-listed") bytes. */ 1129133211Sharti for (n = 0; n <= 31; n++, black_mask >>= 1) 1130133211Sharti if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0)) 1131133211Sharti return Z_BINARY; 1132133211Sharti 1133133211Sharti /* Check for textual ("white-listed") bytes. */ 1134133211Sharti if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0 1135133211Sharti || s->dyn_ltree[13].Freq != 0) 1136133211Sharti return Z_TEXT; 1137133211Sharti for (n = 32; n < LITERALS; n++) 1138133211Sharti if (s->dyn_ltree[n].Freq != 0) 1139133211Sharti return Z_TEXT; 1140133211Sharti 1141133211Sharti /* There are no "black-listed" or "white-listed" bytes: 1142133211Sharti * this stream either is empty or has tolerated ("gray-listed") bytes only. 1143133211Sharti */ 1144133211Sharti return Z_BINARY; 1145133211Sharti} 1146133211Sharti 1147133211Sharti/* =========================================================================== 1148133211Sharti * Reverse the first len bits of a code, using straightforward code (a faster 1149133211Sharti * method would use a table) 1150133211Sharti * IN assertion: 1 <= len <= 15 1151133211Sharti */ 1152133211Shartilocal unsigned bi_reverse(code, len) 1153122394Sharti unsigned code; /* the value to invert */ 1154159063Sharti int len; /* its bit length */ 1155133211Sharti{ 1156122394Sharti register unsigned res = 0; 1157122394Sharti do { 1158122394Sharti res |= code & 1; 1159122394Sharti code >>= 1, res <<= 1; 1160122394Sharti } while (--len > 0); 1161122394Sharti return res >> 1; 1162122394Sharti} 1163122394Sharti 1164122394Sharti/* =========================================================================== 1165133211Sharti * Flush the bit buffer, keeping at most 7 bits in it. 1166133211Sharti */ 1167133211Shartilocal void bi_flush(s) 1168133211Sharti deflate_state *s; 1169133211Sharti{ 1170133211Sharti if (s->bi_valid == 16) { 1171133211Sharti put_short(s, s->bi_buf); 1172133211Sharti s->bi_buf = 0; 1173122394Sharti s->bi_valid = 0; 1174122394Sharti } else if (s->bi_valid >= 8) { 1175133211Sharti put_byte(s, (Byte)s->bi_buf); 1176133211Sharti s->bi_buf >>= 8; 1177122394Sharti s->bi_valid -= 8; 1178122394Sharti } 1179122394Sharti} 1180122394Sharti 1181122394Sharti/* =========================================================================== 1182122394Sharti * Flush the bit buffer and align the output on a byte boundary 1183159063Sharti */ 1184122394Shartilocal void bi_windup(s) 1185122394Sharti deflate_state *s; 1186122394Sharti{ 1187159063Sharti if (s->bi_valid > 8) { 1188122394Sharti put_short(s, s->bi_buf); 1189122394Sharti } else if (s->bi_valid > 0) { 1190122394Sharti put_byte(s, (Byte)s->bi_buf); 1191122394Sharti } 1192122394Sharti s->bi_buf = 0; 1193122394Sharti s->bi_valid = 0; 1194122394Sharti#ifdef DEBUG 1195159063Sharti s->bits_sent = (s->bits_sent+7) & ~7; 1196122394Sharti#endif 1197122394Sharti} 1198133211Sharti 1199133211Sharti/* =========================================================================== 1200133211Sharti * Copy a stored block, storing first the length and its 1201133211Sharti * one's complement if requested. 1202122394Sharti */ 1203133211Shartilocal void copy_block(s, buf, len, header) 1204133211Sharti deflate_state *s; 1205133211Sharti charf *buf; /* the input data */ 1206133211Sharti unsigned len; /* its length */ 1207133211Sharti int header; /* true if block header must be written */ 1208133211Sharti{ 1209133211Sharti bi_windup(s); /* align on byte boundary */ 1210133211Sharti 1211133211Sharti if (header) { 1212133211Sharti put_short(s, (ush)len); 1213133211Sharti put_short(s, (ush)~len); 1214133211Sharti#ifdef DEBUG 1215133211Sharti s->bits_sent += 2*16; 1216133211Sharti#endif 1217133211Sharti } 1218133211Sharti#ifdef DEBUG 1219133211Sharti s->bits_sent += (ulg)len<<3; 1220133211Sharti#endif 1221133211Sharti while (len--) { 1222133211Sharti put_byte(s, *buf++); 1223133211Sharti } 1224133211Sharti} 1225133211Sharti