1168404Spjd/* trees.c -- output deflated data using Huffman coding 2168404Spjd * Copyright (C) 1995-2005 Jean-loup Gailly 3168404Spjd * For conditions of distribution and use, see copyright notice in zlib.h 4168404Spjd */ 5168404Spjd 6168404Spjd#pragma ident "%Z%%M% %I% %E% SMI" 7168404Spjd 8168404Spjd/* 9168404Spjd * ALGORITHM 10168404Spjd * 11168404Spjd * The "deflation" process uses several Huffman trees. The more 12168404Spjd * common source values are represented by shorter bit sequences. 13168404Spjd * 14168404Spjd * Each code tree is stored in a compressed form which is itself 15168404Spjd * a Huffman encoding of the lengths of all the code strings (in 16168404Spjd * ascending order by source values). The actual code strings are 17168404Spjd * reconstructed from the lengths in the inflate process, as described 18168404Spjd * in the deflate specification. 19168404Spjd * 20168404Spjd * REFERENCES 21168404Spjd * 22168404Spjd * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". 23168404Spjd * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc 24168404Spjd * 25168404Spjd * Storer, James A. 26168404Spjd * Data Compression: Methods and Theory, pp. 49-50. 27168404Spjd * Computer Science Press, 1988. ISBN 0-7167-8156-5. 28168404Spjd * 29168404Spjd * Sedgewick, R. 30168404Spjd * Algorithms, p290. 31168404Spjd * Addison-Wesley, 1983. ISBN 0-201-06672-6. 32168404Spjd */ 33168404Spjd 34168404Spjd/* #define GEN_TREES_H */ 35168404Spjd 36168404Spjd#include "deflate.h" 37168404Spjd 38168404Spjd#ifdef DEBUG 39168404Spjd# include <ctype.h> 40168404Spjd#endif 41168404Spjd 42168404Spjd/* =========================================================================== 43168404Spjd * Constants 44168404Spjd */ 45168404Spjd 46168404Spjd#define MAX_BL_BITS 7 47168404Spjd/* Bit length codes must not exceed MAX_BL_BITS bits */ 48168404Spjd 49168404Spjd#define END_BLOCK 256 50168404Spjd/* end of block literal code */ 51168404Spjd 52168404Spjd#define REP_3_6 16 53168404Spjd/* repeat previous bit length 3-6 times (2 bits of repeat count) */ 54168404Spjd 55168404Spjd#define REPZ_3_10 17 56168404Spjd/* repeat a zero length 3-10 times (3 bits of repeat count) */ 57168404Spjd 58168404Spjd#define REPZ_11_138 18 59168404Spjd/* repeat a zero length 11-138 times (7 bits of repeat count) */ 60168404Spjd 61168404Spjdlocal const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ 62168404Spjd = {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}; 63168404Spjd 64168404Spjdlocal const int extra_dbits[D_CODES] /* extra bits for each distance code */ 65168404Spjd = {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}; 66168404Spjd 67168404Spjdlocal const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ 68168404Spjd = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; 69168404Spjd 70168404Spjdlocal const uch bl_order[BL_CODES] 71168404Spjd = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; 72168404Spjd/* The lengths of the bit length codes are sent in order of decreasing 73168404Spjd * probability, to avoid transmitting the lengths for unused bit length codes. 74168404Spjd */ 75168404Spjd 76168404Spjd#define Buf_size (8 * 2*sizeof(char)) 77168404Spjd/* Number of bits used within bi_buf. (bi_buf might be implemented on 78168404Spjd * more than 16 bits on some systems.) 79168404Spjd */ 80168404Spjd 81168404Spjd/* =========================================================================== 82168404Spjd * Local data. These are initialized only once. 83168404Spjd */ 84168404Spjd 85168404Spjd#define DIST_CODE_LEN 512 /* see definition of array dist_code below */ 86168404Spjd 87168404Spjd#if defined(GEN_TREES_H) || !defined(STDC) 88168404Spjd/* non ANSI compilers may not accept trees.h */ 89168404Spjd 90168404Spjdlocal ct_data static_ltree[L_CODES+2]; 91168404Spjd/* The static literal tree. Since the bit lengths are imposed, there is no 92168404Spjd * need for the L_CODES extra codes used during heap construction. However 93168404Spjd * The codes 286 and 287 are needed to build a canonical tree (see _tr_init 94168404Spjd * below). 95168404Spjd */ 96168404Spjd 97168404Spjdlocal ct_data static_dtree[D_CODES]; 98168404Spjd/* The static distance tree. (Actually a trivial tree since all codes use 99168404Spjd * 5 bits.) 100168404Spjd */ 101168404Spjd 102168404Spjduch _dist_code[DIST_CODE_LEN]; 103168404Spjd/* Distance codes. The first 256 values correspond to the distances 104168404Spjd * 3 .. 258, the last 256 values correspond to the top 8 bits of 105168404Spjd * the 15 bit distances. 106168404Spjd */ 107168404Spjd 108168404Spjduch _length_code[MAX_MATCH-MIN_MATCH+1]; 109168404Spjd/* length code for each normalized match length (0 == MIN_MATCH) */ 110168404Spjd 111168404Spjdlocal int base_length[LENGTH_CODES]; 112168404Spjd/* First normalized length for each code (0 = MIN_MATCH) */ 113168404Spjd 114168404Spjdlocal int base_dist[D_CODES]; 115168404Spjd/* First normalized distance for each code (0 = distance of 1) */ 116168404Spjd 117168404Spjd#else 118168404Spjd# include "trees.h" 119168404Spjd#endif /* GEN_TREES_H */ 120168404Spjd 121168404Spjdstruct static_tree_desc_s { 122168404Spjd const ct_data *static_tree; /* static tree or NULL */ 123168404Spjd const intf *extra_bits; /* extra bits for each code or NULL */ 124168404Spjd int extra_base; /* base index for extra_bits */ 125168404Spjd int elems; /* max number of elements in the tree */ 126168404Spjd int max_length; /* max bit length for the codes */ 127168404Spjd}; 128168404Spjd 129168404Spjdlocal static_tree_desc static_l_desc = 130168404Spjd{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; 131168404Spjd 132168404Spjdlocal static_tree_desc static_d_desc = 133168404Spjd{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; 134168404Spjd 135168404Spjdlocal static_tree_desc static_bl_desc = 136168404Spjd{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; 137168404Spjd 138168404Spjd/* =========================================================================== 139168404Spjd * Local (static) routines in this file. 140168404Spjd */ 141168404Spjd 142168404Spjdlocal void tr_static_init OF((void)); 143168404Spjdlocal void init_block OF((deflate_state *s)); 144168404Spjdlocal void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); 145168404Spjdlocal void gen_bitlen OF((deflate_state *s, tree_desc *desc)); 146168404Spjdlocal void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); 147168404Spjdlocal void build_tree OF((deflate_state *s, tree_desc *desc)); 148168404Spjdlocal void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); 149168404Spjdlocal void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); 150168404Spjdlocal int build_bl_tree OF((deflate_state *s)); 151168404Spjdlocal void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, 152168404Spjd int blcodes)); 153168404Spjdlocal void compress_block OF((deflate_state *s, ct_data *ltree, 154168404Spjd ct_data *dtree)); 155168404Spjdlocal void set_data_type OF((deflate_state *s)); 156168404Spjdlocal unsigned bi_reverse OF((unsigned value, int length)); 157168404Spjdlocal void bi_windup OF((deflate_state *s)); 158168404Spjdlocal void bi_flush OF((deflate_state *s)); 159168404Spjdlocal void copy_block OF((deflate_state *s, charf *buf, unsigned len, 160168404Spjd int header)); 161168404Spjd 162168404Spjd#ifdef GEN_TREES_H 163168404Spjdlocal void gen_trees_header OF((void)); 164168404Spjd#endif 165168404Spjd 166168404Spjd#ifndef DEBUG 167168404Spjd# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) 168168404Spjd /* Send a code of the given tree. c and tree must not have side effects */ 169168404Spjd 170168404Spjd#else /* DEBUG */ 171168404Spjd# define send_code(s, c, tree) \ 172168404Spjd { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ 173168404Spjd send_bits(s, tree[c].Code, tree[c].Len); } 174168404Spjd#endif 175168404Spjd 176168404Spjd/* =========================================================================== 177168404Spjd * Output a short LSB first on the stream. 178168404Spjd * IN assertion: there is enough room in pendingBuf. 179168404Spjd */ 180168404Spjd#define put_short(s, w) { \ 181168404Spjd put_byte(s, (uch)((w) & 0xff)); \ 182168404Spjd put_byte(s, (uch)((ush)(w) >> 8)); \ 183168404Spjd} 184168404Spjd 185168404Spjd/* =========================================================================== 186168404Spjd * Send a value on a given number of bits. 187168404Spjd * IN assertion: length <= 16 and value fits in length bits. 188168404Spjd */ 189168404Spjd#ifdef DEBUG 190168404Spjdlocal void send_bits OF((deflate_state *s, int value, int length)); 191168404Spjd 192168404Spjdlocal void send_bits(s, value, length) 193168404Spjd deflate_state *s; 194168404Spjd int value; /* value to send */ 195168404Spjd int length; /* number of bits */ 196168404Spjd{ 197168404Spjd Tracevv((stderr," l %2d v %4x ", length, value)); 198168404Spjd Assert(length > 0 && length <= 15, "invalid length"); 199168404Spjd s->bits_sent += (ulg)length; 200168404Spjd 201168404Spjd /* If not enough room in bi_buf, use (valid) bits from bi_buf and 202168404Spjd * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) 203168404Spjd * unused bits in value. 204168404Spjd */ 205168404Spjd if (s->bi_valid > (int)Buf_size - length) { 206168404Spjd s->bi_buf |= (value << s->bi_valid); 207168404Spjd put_short(s, s->bi_buf); 208168404Spjd s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); 209168404Spjd s->bi_valid += length - Buf_size; 210168404Spjd } else { 211168404Spjd s->bi_buf |= value << s->bi_valid; 212168404Spjd s->bi_valid += length; 213168404Spjd } 214168404Spjd} 215168404Spjd#else /* !DEBUG */ 216168404Spjd 217168404Spjd#define send_bits(s, value, length) \ 218168404Spjd{ int len = length;\ 219168404Spjd if (s->bi_valid > (int)Buf_size - len) {\ 220168404Spjd int val = value;\ 221168404Spjd s->bi_buf |= (val << s->bi_valid);\ 222168404Spjd put_short(s, s->bi_buf);\ 223168404Spjd s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ 224168404Spjd s->bi_valid += len - Buf_size;\ 225168404Spjd } else {\ 226168404Spjd s->bi_buf |= (value) << s->bi_valid;\ 227168404Spjd s->bi_valid += len;\ 228168404Spjd }\ 229168404Spjd} 230168404Spjd#endif /* DEBUG */ 231168404Spjd 232168404Spjd 233168404Spjd/* the arguments must not have side effects */ 234168404Spjd 235168404Spjd/* =========================================================================== 236168404Spjd * Initialize the various 'constant' tables. 237168404Spjd */ 238168404Spjdlocal void tr_static_init() 239168404Spjd{ 240168404Spjd#if defined(GEN_TREES_H) || !defined(STDC) 241168404Spjd static int static_init_done = 0; 242168404Spjd int n; /* iterates over tree elements */ 243168404Spjd int bits; /* bit counter */ 244168404Spjd int length; /* length value */ 245168404Spjd int code; /* code value */ 246168404Spjd int dist; /* distance index */ 247168404Spjd ush bl_count[MAX_BITS+1]; 248168404Spjd /* number of codes at each bit length for an optimal tree */ 249168404Spjd 250168404Spjd if (static_init_done) return; 251168404Spjd 252168404Spjd /* For some embedded targets, global variables are not initialized: */ 253168404Spjd static_l_desc.static_tree = static_ltree; 254168404Spjd static_l_desc.extra_bits = extra_lbits; 255168404Spjd static_d_desc.static_tree = static_dtree; 256168404Spjd static_d_desc.extra_bits = extra_dbits; 257168404Spjd static_bl_desc.extra_bits = extra_blbits; 258168404Spjd 259168404Spjd /* Initialize the mapping length (0..255) -> length code (0..28) */ 260168404Spjd length = 0; 261168404Spjd for (code = 0; code < LENGTH_CODES-1; code++) { 262168404Spjd base_length[code] = length; 263168404Spjd for (n = 0; n < (1<<extra_lbits[code]); n++) { 264168404Spjd _length_code[length++] = (uch)code; 265168404Spjd } 266168404Spjd } 267168404Spjd Assert (length == 256, "tr_static_init: length != 256"); 268168404Spjd /* Note that the length 255 (match length 258) can be represented 269168404Spjd * in two different ways: code 284 + 5 bits or code 285, so we 270168404Spjd * overwrite length_code[255] to use the best encoding: 271168404Spjd */ 272168404Spjd _length_code[length-1] = (uch)code; 273168404Spjd 274168404Spjd /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ 275168404Spjd dist = 0; 276168404Spjd for (code = 0 ; code < 16; code++) { 277168404Spjd base_dist[code] = dist; 278168404Spjd for (n = 0; n < (1<<extra_dbits[code]); n++) { 279168404Spjd _dist_code[dist++] = (uch)code; 280168404Spjd } 281168404Spjd } 282168404Spjd Assert (dist == 256, "tr_static_init: dist != 256"); 283168404Spjd dist >>= 7; /* from now on, all distances are divided by 128 */ 284168404Spjd for ( ; code < D_CODES; code++) { 285168404Spjd base_dist[code] = dist << 7; 286168404Spjd for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { 287168404Spjd _dist_code[256 + dist++] = (uch)code; 288168404Spjd } 289168404Spjd } 290168404Spjd Assert (dist == 256, "tr_static_init: 256+dist != 512"); 291168404Spjd 292168404Spjd /* Construct the codes of the static literal tree */ 293168404Spjd for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; 294168404Spjd n = 0; 295168404Spjd while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; 296168404Spjd while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; 297168404Spjd while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; 298168404Spjd while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; 299168404Spjd /* Codes 286 and 287 do not exist, but we must include them in the 300168404Spjd * tree construction to get a canonical Huffman tree (longest code 301168404Spjd * all ones) 302168404Spjd */ 303168404Spjd gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); 304168404Spjd 305168404Spjd /* The static distance tree is trivial: */ 306168404Spjd for (n = 0; n < D_CODES; n++) { 307168404Spjd static_dtree[n].Len = 5; 308168404Spjd static_dtree[n].Code = bi_reverse((unsigned)n, 5); 309168404Spjd } 310168404Spjd static_init_done = 1; 311168404Spjd 312168404Spjd# ifdef GEN_TREES_H 313168404Spjd gen_trees_header(); 314168404Spjd# endif 315168404Spjd#endif /* defined(GEN_TREES_H) || !defined(STDC) */ 316168404Spjd} 317168404Spjd 318168404Spjd/* =========================================================================== 319168404Spjd * Genererate the file trees.h describing the static trees. 320168404Spjd */ 321168404Spjd#ifdef GEN_TREES_H 322168404Spjd# ifndef DEBUG 323168404Spjd# include <stdio.h> 324168404Spjd# endif 325168404Spjd 326168404Spjd# define SEPARATOR(i, last, width) \ 327168404Spjd ((i) == (last)? "\n};\n\n" : \ 328168404Spjd ((i) % (width) == (width)-1 ? ",\n" : ", ")) 329168404Spjd 330168404Spjdvoid gen_trees_header() 331168404Spjd{ 332168404Spjd FILE *header = fopen("trees.h", "w"); 333168404Spjd int i; 334168404Spjd 335168404Spjd Assert (header != NULL, "Can't open trees.h"); 336168404Spjd fprintf(header, 337168404Spjd "/* header created automatically with -DGEN_TREES_H */\n\n"); 338168404Spjd 339168404Spjd fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); 340168404Spjd for (i = 0; i < L_CODES+2; i++) { 341168404Spjd fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, 342168404Spjd static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); 343168404Spjd } 344168404Spjd 345168404Spjd fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); 346168404Spjd for (i = 0; i < D_CODES; i++) { 347168404Spjd fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, 348168404Spjd static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); 349168404Spjd } 350168404Spjd 351168404Spjd fprintf(header, "const uch _dist_code[DIST_CODE_LEN] = {\n"); 352168404Spjd for (i = 0; i < DIST_CODE_LEN; i++) { 353168404Spjd fprintf(header, "%2u%s", _dist_code[i], 354168404Spjd SEPARATOR(i, DIST_CODE_LEN-1, 20)); 355168404Spjd } 356168404Spjd 357168404Spjd fprintf(header, "const uch _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); 358168404Spjd for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { 359168404Spjd fprintf(header, "%2u%s", _length_code[i], 360168404Spjd SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); 361168404Spjd } 362168404Spjd 363168404Spjd fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); 364168404Spjd for (i = 0; i < LENGTH_CODES; i++) { 365168404Spjd fprintf(header, "%1u%s", base_length[i], 366168404Spjd SEPARATOR(i, LENGTH_CODES-1, 20)); 367168404Spjd } 368168404Spjd 369168404Spjd fprintf(header, "local const int base_dist[D_CODES] = {\n"); 370168404Spjd for (i = 0; i < D_CODES; i++) { 371168404Spjd fprintf(header, "%5u%s", base_dist[i], 372168404Spjd SEPARATOR(i, D_CODES-1, 10)); 373168404Spjd } 374168404Spjd 375168404Spjd fclose(header); 376168404Spjd} 377168404Spjd#endif /* GEN_TREES_H */ 378168404Spjd 379168404Spjd/* =========================================================================== 380168404Spjd * Initialize the tree data structures for a new zlib stream. 381168404Spjd */ 382168404Spjdvoid _tr_init(s) 383168404Spjd deflate_state *s; 384168404Spjd{ 385168404Spjd tr_static_init(); 386168404Spjd 387168404Spjd s->l_desc.dyn_tree = s->dyn_ltree; 388168404Spjd s->l_desc.stat_desc = &static_l_desc; 389168404Spjd 390168404Spjd s->d_desc.dyn_tree = s->dyn_dtree; 391168404Spjd s->d_desc.stat_desc = &static_d_desc; 392168404Spjd 393168404Spjd s->bl_desc.dyn_tree = s->bl_tree; 394168404Spjd s->bl_desc.stat_desc = &static_bl_desc; 395168404Spjd 396168404Spjd s->bi_buf = 0; 397168404Spjd s->bi_valid = 0; 398168404Spjd s->last_eob_len = 8; /* enough lookahead for inflate */ 399168404Spjd#ifdef DEBUG 400168404Spjd s->compressed_len = 0L; 401168404Spjd s->bits_sent = 0L; 402168404Spjd#endif 403168404Spjd 404168404Spjd /* Initialize the first block of the first file: */ 405168404Spjd init_block(s); 406168404Spjd} 407168404Spjd 408168404Spjd/* =========================================================================== 409168404Spjd * Initialize a new block. 410168404Spjd */ 411168404Spjdlocal void init_block(s) 412168404Spjd deflate_state *s; 413168404Spjd{ 414168404Spjd int n; /* iterates over tree elements */ 415168404Spjd 416168404Spjd /* Initialize the trees. */ 417168404Spjd for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; 418168404Spjd for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; 419168404Spjd for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; 420168404Spjd 421168404Spjd s->dyn_ltree[END_BLOCK].Freq = 1; 422168404Spjd s->opt_len = s->static_len = 0L; 423168404Spjd s->last_lit = s->matches = 0; 424168404Spjd} 425168404Spjd 426168404Spjd#define SMALLEST 1 427168404Spjd/* Index within the heap array of least frequent node in the Huffman tree */ 428168404Spjd 429168404Spjd 430168404Spjd/* =========================================================================== 431168404Spjd * Remove the smallest element from the heap and recreate the heap with 432168404Spjd * one less element. Updates heap and heap_len. 433168404Spjd */ 434168404Spjd#define pqremove(s, tree, top) \ 435168404Spjd{\ 436168404Spjd top = s->heap[SMALLEST]; \ 437168404Spjd s->heap[SMALLEST] = s->heap[s->heap_len--]; \ 438168404Spjd pqdownheap(s, tree, SMALLEST); \ 439168404Spjd} 440168404Spjd 441168404Spjd/* =========================================================================== 442168404Spjd * Compares to subtrees, using the tree depth as tie breaker when 443168404Spjd * the subtrees have equal frequency. This minimizes the worst case length. 444168404Spjd */ 445168404Spjd#define smaller(tree, n, m, depth) \ 446168404Spjd (tree[n].Freq < tree[m].Freq || \ 447168404Spjd (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) 448168404Spjd 449168404Spjd/* =========================================================================== 450168404Spjd * Restore the heap property by moving down the tree starting at node k, 451168404Spjd * exchanging a node with the smallest of its two sons if necessary, stopping 452168404Spjd * when the heap property is re-established (each father smaller than its 453168404Spjd * two sons). 454168404Spjd */ 455168404Spjdlocal void pqdownheap(s, tree, k) 456168404Spjd deflate_state *s; 457168404Spjd ct_data *tree; /* the tree to restore */ 458168404Spjd int k; /* node to move down */ 459168404Spjd{ 460168404Spjd int v = s->heap[k]; 461168404Spjd int j = k << 1; /* left son of k */ 462168404Spjd while (j <= s->heap_len) { 463168404Spjd /* Set j to the smallest of the two sons: */ 464168404Spjd if (j < s->heap_len && 465168404Spjd smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { 466168404Spjd j++; 467168404Spjd } 468168404Spjd /* Exit if v is smaller than both sons */ 469168404Spjd if (smaller(tree, v, s->heap[j], s->depth)) break; 470168404Spjd 471168404Spjd /* Exchange v with the smallest son */ 472168404Spjd s->heap[k] = s->heap[j]; k = j; 473168404Spjd 474168404Spjd /* And continue down the tree, setting j to the left son of k */ 475168404Spjd j <<= 1; 476168404Spjd } 477168404Spjd s->heap[k] = v; 478168404Spjd} 479168404Spjd 480168404Spjd/* =========================================================================== 481168404Spjd * Compute the optimal bit lengths for a tree and update the total bit length 482168404Spjd * for the current block. 483168404Spjd * IN assertion: the fields freq and dad are set, heap[heap_max] and 484168404Spjd * above are the tree nodes sorted by increasing frequency. 485168404Spjd * OUT assertions: the field len is set to the optimal bit length, the 486168404Spjd * array bl_count contains the frequencies for each bit length. 487168404Spjd * The length opt_len is updated; static_len is also updated if stree is 488168404Spjd * not null. 489168404Spjd */ 490168404Spjdlocal void gen_bitlen(s, desc) 491168404Spjd deflate_state *s; 492168404Spjd tree_desc *desc; /* the tree descriptor */ 493168404Spjd{ 494168404Spjd ct_data *tree = desc->dyn_tree; 495168404Spjd int max_code = desc->max_code; 496168404Spjd const ct_data *stree = desc->stat_desc->static_tree; 497168404Spjd const intf *extra = desc->stat_desc->extra_bits; 498168404Spjd int base = desc->stat_desc->extra_base; 499168404Spjd int max_length = desc->stat_desc->max_length; 500168404Spjd int h; /* heap index */ 501168404Spjd int n, m; /* iterate over the tree elements */ 502168404Spjd int bits; /* bit length */ 503168404Spjd int xbits; /* extra bits */ 504168404Spjd ush f; /* frequency */ 505168404Spjd int overflow = 0; /* number of elements with bit length too large */ 506168404Spjd 507168404Spjd for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; 508168404Spjd 509168404Spjd /* In a first pass, compute the optimal bit lengths (which may 510168404Spjd * overflow in the case of the bit length tree). 511168404Spjd */ 512168404Spjd tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ 513168404Spjd 514168404Spjd for (h = s->heap_max+1; h < HEAP_SIZE; h++) { 515168404Spjd n = s->heap[h]; 516168404Spjd bits = tree[tree[n].Dad].Len + 1; 517168404Spjd if (bits > max_length) bits = max_length, overflow++; 518168404Spjd tree[n].Len = (ush)bits; 519168404Spjd /* We overwrite tree[n].Dad which is no longer needed */ 520168404Spjd 521168404Spjd if (n > max_code) continue; /* not a leaf node */ 522168404Spjd 523168404Spjd s->bl_count[bits]++; 524168404Spjd xbits = 0; 525168404Spjd if (n >= base) xbits = extra[n-base]; 526168404Spjd f = tree[n].Freq; 527168404Spjd s->opt_len += (ulg)f * (bits + xbits); 528168404Spjd if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); 529168404Spjd } 530168404Spjd if (overflow == 0) return; 531168404Spjd 532168404Spjd Trace((stderr,"\nbit length overflow\n")); 533168404Spjd /* This happens for example on obj2 and pic of the Calgary corpus */ 534168404Spjd 535168404Spjd /* Find the first bit length which could increase: */ 536168404Spjd do { 537168404Spjd bits = max_length-1; 538168404Spjd while (s->bl_count[bits] == 0) bits--; 539168404Spjd s->bl_count[bits]--; /* move one leaf down the tree */ 540168404Spjd s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ 541168404Spjd s->bl_count[max_length]--; 542168404Spjd /* The brother of the overflow item also moves one step up, 543168404Spjd * but this does not affect bl_count[max_length] 544168404Spjd */ 545168404Spjd overflow -= 2; 546168404Spjd } while (overflow > 0); 547168404Spjd 548168404Spjd /* Now recompute all bit lengths, scanning in increasing frequency. 549168404Spjd * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all 550168404Spjd * lengths instead of fixing only the wrong ones. This idea is taken 551168404Spjd * from 'ar' written by Haruhiko Okumura.) 552168404Spjd */ 553168404Spjd for (bits = max_length; bits != 0; bits--) { 554168404Spjd n = s->bl_count[bits]; 555168404Spjd while (n != 0) { 556168404Spjd m = s->heap[--h]; 557168404Spjd if (m > max_code) continue; 558168404Spjd if ((unsigned) tree[m].Len != (unsigned) bits) { 559168404Spjd Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); 560168404Spjd s->opt_len += ((long)bits - (long)tree[m].Len) 561168404Spjd *(long)tree[m].Freq; 562168404Spjd tree[m].Len = (ush)bits; 563168404Spjd } 564168404Spjd n--; 565168404Spjd } 566168404Spjd } 567168404Spjd} 568168404Spjd 569168404Spjd/* =========================================================================== 570168404Spjd * Generate the codes for a given tree and bit counts (which need not be 571168404Spjd * optimal). 572168404Spjd * IN assertion: the array bl_count contains the bit length statistics for 573168404Spjd * the given tree and the field len is set for all tree elements. 574168404Spjd * OUT assertion: the field code is set for all tree elements of non 575168404Spjd * zero code length. 576168404Spjd */ 577168404Spjdlocal void gen_codes (tree, max_code, bl_count) 578168404Spjd ct_data *tree; /* the tree to decorate */ 579168404Spjd int max_code; /* largest code with non zero frequency */ 580168404Spjd ushf *bl_count; /* number of codes at each bit length */ 581168404Spjd{ 582168404Spjd ush next_code[MAX_BITS+1]; /* next code value for each bit length */ 583168404Spjd ush code = 0; /* running code value */ 584168404Spjd int bits; /* bit index */ 585168404Spjd int n; /* code index */ 586168404Spjd 587168404Spjd /* The distribution counts are first used to generate the code values 588168404Spjd * without bit reversal. 589168404Spjd */ 590168404Spjd for (bits = 1; bits <= MAX_BITS; bits++) { 591168404Spjd next_code[bits] = code = (code + bl_count[bits-1]) << 1; 592168404Spjd } 593168404Spjd /* Check that the bit counts in bl_count are consistent. The last code 594168404Spjd * must be all ones. 595168404Spjd */ 596168404Spjd Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, 597168404Spjd "inconsistent bit counts"); 598168404Spjd Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); 599168404Spjd 600168404Spjd for (n = 0; n <= max_code; n++) { 601168404Spjd int len = tree[n].Len; 602168404Spjd if (len == 0) continue; 603168404Spjd /* Now reverse the bits */ 604168404Spjd tree[n].Code = bi_reverse(next_code[len]++, len); 605168404Spjd 606168404Spjd Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", 607168404Spjd n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); 608168404Spjd } 609168404Spjd} 610168404Spjd 611168404Spjd/* =========================================================================== 612168404Spjd * Construct one Huffman tree and assigns the code bit strings and lengths. 613168404Spjd * Update the total bit length for the current block. 614168404Spjd * IN assertion: the field freq is set for all tree elements. 615168404Spjd * OUT assertions: the fields len and code are set to the optimal bit length 616168404Spjd * and corresponding code. The length opt_len is updated; static_len is 617168404Spjd * also updated if stree is not null. The field max_code is set. 618168404Spjd */ 619168404Spjdlocal void build_tree(s, desc) 620168404Spjd deflate_state *s; 621168404Spjd tree_desc *desc; /* the tree descriptor */ 622168404Spjd{ 623168404Spjd ct_data *tree = desc->dyn_tree; 624168404Spjd const ct_data *stree = desc->stat_desc->static_tree; 625168404Spjd int elems = desc->stat_desc->elems; 626168404Spjd int n, m; /* iterate over heap elements */ 627168404Spjd int max_code = -1; /* largest code with non zero frequency */ 628168404Spjd int node; /* new node being created */ 629168404Spjd 630168404Spjd /* Construct the initial heap, with least frequent element in 631168404Spjd * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. 632168404Spjd * heap[0] is not used. 633168404Spjd */ 634168404Spjd s->heap_len = 0, s->heap_max = HEAP_SIZE; 635168404Spjd 636168404Spjd for (n = 0; n < elems; n++) { 637168404Spjd if (tree[n].Freq != 0) { 638168404Spjd s->heap[++(s->heap_len)] = max_code = n; 639168404Spjd s->depth[n] = 0; 640168404Spjd } else { 641168404Spjd tree[n].Len = 0; 642168404Spjd } 643168404Spjd } 644168404Spjd 645168404Spjd /* The pkzip format requires that at least one distance code exists, 646168404Spjd * and that at least one bit should be sent even if there is only one 647168404Spjd * possible code. So to avoid special checks later on we force at least 648168404Spjd * two codes of non zero frequency. 649168404Spjd */ 650168404Spjd while (s->heap_len < 2) { 651168404Spjd node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); 652168404Spjd tree[node].Freq = 1; 653168404Spjd s->depth[node] = 0; 654168404Spjd s->opt_len--; if (stree) s->static_len -= stree[node].Len; 655168404Spjd /* node is 0 or 1 so it does not have extra bits */ 656168404Spjd } 657168404Spjd desc->max_code = max_code; 658168404Spjd 659168404Spjd /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, 660168404Spjd * establish sub-heaps of increasing lengths: 661168404Spjd */ 662168404Spjd for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); 663168404Spjd 664168404Spjd /* Construct the Huffman tree by repeatedly combining the least two 665168404Spjd * frequent nodes. 666168404Spjd */ 667168404Spjd node = elems; /* next internal node of the tree */ 668168404Spjd do { 669168404Spjd pqremove(s, tree, n); /* n = node of least frequency */ 670168404Spjd m = s->heap[SMALLEST]; /* m = node of next least frequency */ 671168404Spjd 672168404Spjd s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ 673168404Spjd s->heap[--(s->heap_max)] = m; 674168404Spjd 675168404Spjd /* Create a new node father of n and m */ 676168404Spjd tree[node].Freq = tree[n].Freq + tree[m].Freq; 677168404Spjd s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? 678168404Spjd s->depth[n] : s->depth[m]) + 1); 679168404Spjd tree[n].Dad = tree[m].Dad = (ush)node; 680168404Spjd#ifdef DUMP_BL_TREE 681168404Spjd if (tree == s->bl_tree) { 682168404Spjd fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", 683168404Spjd node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); 684168404Spjd } 685168404Spjd#endif 686168404Spjd /* and insert the new node in the heap */ 687168404Spjd s->heap[SMALLEST] = node++; 688168404Spjd pqdownheap(s, tree, SMALLEST); 689168404Spjd 690168404Spjd } while (s->heap_len >= 2); 691168404Spjd 692168404Spjd s->heap[--(s->heap_max)] = s->heap[SMALLEST]; 693168404Spjd 694168404Spjd /* At this point, the fields freq and dad are set. We can now 695168404Spjd * generate the bit lengths. 696168404Spjd */ 697168404Spjd gen_bitlen(s, (tree_desc *)desc); 698168404Spjd 699168404Spjd /* The field len is now set, we can generate the bit codes */ 700168404Spjd gen_codes ((ct_data *)tree, max_code, s->bl_count); 701168404Spjd} 702168404Spjd 703168404Spjd/* =========================================================================== 704168404Spjd * Scan a literal or distance tree to determine the frequencies of the codes 705168404Spjd * in the bit length tree. 706168404Spjd */ 707168404Spjdlocal void scan_tree (s, tree, max_code) 708168404Spjd deflate_state *s; 709168404Spjd ct_data *tree; /* the tree to be scanned */ 710168404Spjd int max_code; /* and its largest code of non zero frequency */ 711168404Spjd{ 712168404Spjd int n; /* iterates over all tree elements */ 713168404Spjd int prevlen = -1; /* last emitted length */ 714168404Spjd int curlen; /* length of current code */ 715168404Spjd int nextlen = tree[0].Len; /* length of next code */ 716168404Spjd int count = 0; /* repeat count of the current code */ 717168404Spjd int max_count = 7; /* max repeat count */ 718168404Spjd int min_count = 4; /* min repeat count */ 719168404Spjd 720168404Spjd if (nextlen == 0) max_count = 138, min_count = 3; 721168404Spjd tree[max_code+1].Len = (ush)0xffff; /* guard */ 722168404Spjd 723168404Spjd for (n = 0; n <= max_code; n++) { 724168404Spjd curlen = nextlen; nextlen = tree[n+1].Len; 725168404Spjd if (++count < max_count && curlen == nextlen) { 726168404Spjd continue; 727168404Spjd } else if (count < min_count) { 728168404Spjd s->bl_tree[curlen].Freq += count; 729168404Spjd } else if (curlen != 0) { 730168404Spjd if (curlen != prevlen) s->bl_tree[curlen].Freq++; 731168404Spjd s->bl_tree[REP_3_6].Freq++; 732168404Spjd } else if (count <= 10) { 733168404Spjd s->bl_tree[REPZ_3_10].Freq++; 734168404Spjd } else { 735168404Spjd s->bl_tree[REPZ_11_138].Freq++; 736168404Spjd } 737168404Spjd count = 0; prevlen = curlen; 738168404Spjd if (nextlen == 0) { 739168404Spjd max_count = 138, min_count = 3; 740168404Spjd } else if (curlen == nextlen) { 741168404Spjd max_count = 6, min_count = 3; 742168404Spjd } else { 743168404Spjd max_count = 7, min_count = 4; 744168404Spjd } 745168404Spjd } 746168404Spjd} 747168404Spjd 748168404Spjd/* =========================================================================== 749168404Spjd * Send a literal or distance tree in compressed form, using the codes in 750168404Spjd * bl_tree. 751168404Spjd */ 752168404Spjdlocal void send_tree (s, tree, max_code) 753168404Spjd deflate_state *s; 754168404Spjd ct_data *tree; /* the tree to be scanned */ 755168404Spjd int max_code; /* and its largest code of non zero frequency */ 756168404Spjd{ 757168404Spjd int n; /* iterates over all tree elements */ 758168404Spjd int prevlen = -1; /* last emitted length */ 759168404Spjd int curlen; /* length of current code */ 760168404Spjd int nextlen = tree[0].Len; /* length of next code */ 761168404Spjd int count = 0; /* repeat count of the current code */ 762168404Spjd int max_count = 7; /* max repeat count */ 763168404Spjd int min_count = 4; /* min repeat count */ 764168404Spjd 765168404Spjd /* tree[max_code+1].Len = -1; */ /* guard already set */ 766168404Spjd if (nextlen == 0) max_count = 138, min_count = 3; 767168404Spjd 768168404Spjd for (n = 0; n <= max_code; n++) { 769168404Spjd curlen = nextlen; nextlen = tree[n+1].Len; 770168404Spjd if (++count < max_count && curlen == nextlen) { 771168404Spjd continue; 772168404Spjd } else if (count < min_count) { 773168404Spjd do { send_code(s, curlen, s->bl_tree); } while (--count != 0); 774168404Spjd 775168404Spjd } else if (curlen != 0) { 776168404Spjd if (curlen != prevlen) { 777168404Spjd send_code(s, curlen, s->bl_tree); count--; 778168404Spjd } 779168404Spjd Assert(count >= 3 && count <= 6, " 3_6?"); 780168404Spjd send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); 781168404Spjd 782168404Spjd } else if (count <= 10) { 783168404Spjd send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); 784168404Spjd 785168404Spjd } else { 786168404Spjd send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); 787168404Spjd } 788168404Spjd count = 0; prevlen = curlen; 789168404Spjd if (nextlen == 0) { 790168404Spjd max_count = 138, min_count = 3; 791168404Spjd } else if (curlen == nextlen) { 792168404Spjd max_count = 6, min_count = 3; 793168404Spjd } else { 794168404Spjd max_count = 7, min_count = 4; 795168404Spjd } 796168404Spjd } 797168404Spjd} 798168404Spjd 799168404Spjd/* =========================================================================== 800168404Spjd * Construct the Huffman tree for the bit lengths and return the index in 801168404Spjd * bl_order of the last bit length code to send. 802168404Spjd */ 803168404Spjdlocal int build_bl_tree(s) 804168404Spjd deflate_state *s; 805168404Spjd{ 806168404Spjd int max_blindex; /* index of last bit length code of non zero freq */ 807168404Spjd 808168404Spjd /* Determine the bit length frequencies for literal and distance trees */ 809168404Spjd scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); 810168404Spjd scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); 811168404Spjd 812168404Spjd /* Build the bit length tree: */ 813168404Spjd build_tree(s, (tree_desc *)(&(s->bl_desc))); 814168404Spjd /* opt_len now includes the length of the tree representations, except 815168404Spjd * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. 816168404Spjd */ 817168404Spjd 818168404Spjd /* Determine the number of bit length codes to send. The pkzip format 819168404Spjd * requires that at least 4 bit length codes be sent. (appnote.txt says 820168404Spjd * 3 but the actual value used is 4.) 821168404Spjd */ 822168404Spjd for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { 823168404Spjd if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; 824168404Spjd } 825168404Spjd /* Update opt_len to include the bit length tree and counts */ 826168404Spjd s->opt_len += 3*(max_blindex+1) + 5+5+4; 827168404Spjd Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", 828168404Spjd s->opt_len, s->static_len)); 829168404Spjd 830168404Spjd return max_blindex; 831168404Spjd} 832168404Spjd 833168404Spjd/* =========================================================================== 834168404Spjd * Send the header for a block using dynamic Huffman trees: the counts, the 835168404Spjd * lengths of the bit length codes, the literal tree and the distance tree. 836168404Spjd * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. 837168404Spjd */ 838168404Spjdlocal void send_all_trees(s, lcodes, dcodes, blcodes) 839168404Spjd deflate_state *s; 840168404Spjd int lcodes, dcodes, blcodes; /* number of codes for each tree */ 841168404Spjd{ 842168404Spjd int rank; /* index in bl_order */ 843168404Spjd 844168404Spjd Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); 845168404Spjd Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, 846168404Spjd "too many codes"); 847168404Spjd Tracev((stderr, "\nbl counts: ")); 848168404Spjd send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ 849168404Spjd send_bits(s, dcodes-1, 5); 850168404Spjd send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ 851168404Spjd for (rank = 0; rank < blcodes; rank++) { 852168404Spjd Tracev((stderr, "\nbl code %2d ", bl_order[rank])); 853168404Spjd send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); 854168404Spjd } 855168404Spjd Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); 856168404Spjd 857168404Spjd send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ 858168404Spjd Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); 859168404Spjd 860168404Spjd send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ 861168404Spjd Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); 862168404Spjd} 863168404Spjd 864168404Spjd/* =========================================================================== 865168404Spjd * Send a stored block 866168404Spjd */ 867168404Spjdvoid _tr_stored_block(s, buf, stored_len, eof) 868168404Spjd deflate_state *s; 869168404Spjd charf *buf; /* input block */ 870168404Spjd ulg stored_len; /* length of input block */ 871168404Spjd int eof; /* true if this is the last block for a file */ 872168404Spjd{ 873168404Spjd send_bits(s, (STORED_BLOCK<<1)+eof, 3); /* send block type */ 874168404Spjd#ifdef DEBUG 875168404Spjd s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; 876168404Spjd s->compressed_len += (stored_len + 4) << 3; 877168404Spjd#endif 878168404Spjd copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ 879168404Spjd} 880168404Spjd 881168404Spjd/* =========================================================================== 882168404Spjd * Send one empty static block to give enough lookahead for inflate. 883168404Spjd * This takes 10 bits, of which 7 may remain in the bit buffer. 884168404Spjd * The current inflate code requires 9 bits of lookahead. If the 885168404Spjd * last two codes for the previous block (real code plus EOB) were coded 886168404Spjd * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode 887168404Spjd * the last real code. In this case we send two empty static blocks instead 888168404Spjd * of one. (There are no problems if the previous block is stored or fixed.) 889168404Spjd * To simplify the code, we assume the worst case of last real code encoded 890168404Spjd * on one bit only. 891168404Spjd */ 892168404Spjdvoid _tr_align(s) 893168404Spjd deflate_state *s; 894168404Spjd{ 895168404Spjd send_bits(s, STATIC_TREES<<1, 3); 896168404Spjd send_code(s, END_BLOCK, static_ltree); 897168404Spjd#ifdef DEBUG 898168404Spjd s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ 899168404Spjd#endif 900168404Spjd bi_flush(s); 901168404Spjd /* Of the 10 bits for the empty block, we have already sent 902168404Spjd * (10 - bi_valid) bits. The lookahead for the last real code (before 903168404Spjd * the EOB of the previous block) was thus at least one plus the length 904168404Spjd * of the EOB plus what we have just sent of the empty static block. 905168404Spjd */ 906168404Spjd if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { 907168404Spjd send_bits(s, STATIC_TREES<<1, 3); 908168404Spjd send_code(s, END_BLOCK, static_ltree); 909168404Spjd#ifdef DEBUG 910168404Spjd s->compressed_len += 10L; 911168404Spjd#endif 912168404Spjd bi_flush(s); 913168404Spjd } 914168404Spjd s->last_eob_len = 7; 915168404Spjd} 916168404Spjd 917168404Spjd/* =========================================================================== 918168404Spjd * Determine the best encoding for the current block: dynamic trees, static 919168404Spjd * trees or store, and output the encoded block to the zip file. 920168404Spjd */ 921168404Spjdvoid _tr_flush_block(s, buf, stored_len, eof) 922168404Spjd deflate_state *s; 923168404Spjd charf *buf; /* input block, or NULL if too old */ 924168404Spjd ulg stored_len; /* length of input block */ 925168404Spjd int eof; /* true if this is the last block for a file */ 926168404Spjd{ 927168404Spjd ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ 928168404Spjd int max_blindex = 0; /* index of last bit length code of non zero freq */ 929168404Spjd 930168404Spjd /* Build the Huffman trees unless a stored block is forced */ 931168404Spjd if (s->level > 0) { 932168404Spjd 933168404Spjd /* Check if the file is binary or text */ 934168404Spjd if (stored_len > 0 && s->strm->data_type == Z_UNKNOWN) 935168404Spjd set_data_type(s); 936168404Spjd 937168404Spjd /* Construct the literal and distance trees */ 938168404Spjd build_tree(s, (tree_desc *)(&(s->l_desc))); 939168404Spjd Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, 940168404Spjd s->static_len)); 941168404Spjd 942168404Spjd build_tree(s, (tree_desc *)(&(s->d_desc))); 943168404Spjd Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, 944168404Spjd s->static_len)); 945168404Spjd /* At this point, opt_len and static_len are the total bit lengths of 946168404Spjd * the compressed block data, excluding the tree representations. 947168404Spjd */ 948168404Spjd 949168404Spjd /* Build the bit length tree for the above two trees, and get the index 950168404Spjd * in bl_order of the last bit length code to send. 951168404Spjd */ 952168404Spjd max_blindex = build_bl_tree(s); 953168404Spjd 954168404Spjd /* Determine the best encoding. Compute the block lengths in bytes. */ 955168404Spjd opt_lenb = (s->opt_len+3+7)>>3; 956168404Spjd static_lenb = (s->static_len+3+7)>>3; 957168404Spjd 958168404Spjd Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", 959168404Spjd opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, 960168404Spjd s->last_lit)); 961168404Spjd 962168404Spjd if (static_lenb <= opt_lenb) opt_lenb = static_lenb; 963168404Spjd 964168404Spjd } else { 965168404Spjd Assert(buf != (char*)0, "lost buf"); 966168404Spjd opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ 967168404Spjd } 968168404Spjd 969168404Spjd#ifdef FORCE_STORED 970168404Spjd if (buf != (char*)0) { /* force stored block */ 971168404Spjd#else 972168404Spjd if (stored_len+4 <= opt_lenb && buf != (char*)0) { 973168404Spjd /* 4: two words for the lengths */ 974168404Spjd#endif 975168404Spjd /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. 976168404Spjd * Otherwise we can't have processed more than WSIZE input bytes since 977168404Spjd * the last block flush, because compression would have been 978168404Spjd * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to 979168404Spjd * transform a block into a stored block. 980168404Spjd */ 981168404Spjd _tr_stored_block(s, buf, stored_len, eof); 982168404Spjd 983168404Spjd#ifdef FORCE_STATIC 984168404Spjd } else if (static_lenb >= 0) { /* force static trees */ 985168404Spjd#else 986168404Spjd } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { 987168404Spjd#endif 988168404Spjd send_bits(s, (STATIC_TREES<<1)+eof, 3); 989168404Spjd compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); 990168404Spjd#ifdef DEBUG 991168404Spjd s->compressed_len += 3 + s->static_len; 992168404Spjd#endif 993168404Spjd } else { 994168404Spjd send_bits(s, (DYN_TREES<<1)+eof, 3); 995168404Spjd send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, 996168404Spjd max_blindex+1); 997168404Spjd compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); 998168404Spjd#ifdef DEBUG 999168404Spjd s->compressed_len += 3 + s->opt_len; 1000168404Spjd#endif 1001168404Spjd } 1002168404Spjd Assert (s->compressed_len == s->bits_sent, "bad compressed size"); 1003168404Spjd /* The above check is made mod 2^32, for files larger than 512 MB 1004168404Spjd * and uLong implemented on 32 bits. 1005168404Spjd */ 1006168404Spjd init_block(s); 1007168404Spjd 1008168404Spjd if (eof) { 1009168404Spjd bi_windup(s); 1010168404Spjd#ifdef DEBUG 1011168404Spjd s->compressed_len += 7; /* align on byte boundary */ 1012168404Spjd#endif 1013168404Spjd } 1014168404Spjd Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, 1015168404Spjd s->compressed_len-7*eof)); 1016168404Spjd} 1017168404Spjd 1018168404Spjd/* =========================================================================== 1019168404Spjd * Save the match info and tally the frequency counts. Return true if 1020168404Spjd * the current block must be flushed. 1021168404Spjd */ 1022168404Spjdint _tr_tally (s, dist, lc) 1023168404Spjd deflate_state *s; 1024168404Spjd unsigned dist; /* distance of matched string */ 1025168404Spjd unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ 1026168404Spjd{ 1027168404Spjd s->d_buf[s->last_lit] = (ush)dist; 1028168404Spjd s->l_buf[s->last_lit++] = (uch)lc; 1029168404Spjd if (dist == 0) { 1030168404Spjd /* lc is the unmatched char */ 1031168404Spjd s->dyn_ltree[lc].Freq++; 1032168404Spjd } else { 1033168404Spjd s->matches++; 1034168404Spjd /* Here, lc is the match length - MIN_MATCH */ 1035168404Spjd dist--; /* dist = match distance - 1 */ 1036168404Spjd Assert((ush)dist < (ush)MAX_DIST(s) && 1037168404Spjd (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && 1038168404Spjd (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); 1039168404Spjd 1040168404Spjd s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; 1041168404Spjd s->dyn_dtree[d_code(dist)].Freq++; 1042168404Spjd } 1043168404Spjd 1044168404Spjd#ifdef TRUNCATE_BLOCK 1045168404Spjd /* Try to guess if it is profitable to stop the current block here */ 1046168404Spjd if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { 1047168404Spjd /* Compute an upper bound for the compressed length */ 1048168404Spjd ulg out_length = (ulg)s->last_lit*8L; 1049168404Spjd ulg in_length = (ulg)((long)s->strstart - s->block_start); 1050168404Spjd int dcode; 1051168404Spjd for (dcode = 0; dcode < D_CODES; dcode++) { 1052168404Spjd out_length += (ulg)s->dyn_dtree[dcode].Freq * 1053168404Spjd (5L+extra_dbits[dcode]); 1054168404Spjd } 1055168404Spjd out_length >>= 3; 1056168404Spjd Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", 1057168404Spjd s->last_lit, in_length, out_length, 1058168404Spjd 100L - out_length*100L/in_length)); 1059168404Spjd if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; 1060168404Spjd } 1061168404Spjd#endif 1062168404Spjd return (s->last_lit == s->lit_bufsize-1); 1063168404Spjd /* We avoid equality with lit_bufsize because of wraparound at 64K 1064168404Spjd * on 16 bit machines and because stored blocks are restricted to 1065168404Spjd * 64K-1 bytes. 1066168404Spjd */ 1067168404Spjd} 1068168404Spjd 1069168404Spjd/* =========================================================================== 1070168404Spjd * Send the block data compressed using the given Huffman trees 1071168404Spjd */ 1072168404Spjdlocal void compress_block(s, ltree, dtree) 1073168404Spjd deflate_state *s; 1074168404Spjd ct_data *ltree; /* literal tree */ 1075168404Spjd ct_data *dtree; /* distance tree */ 1076168404Spjd{ 1077168404Spjd unsigned dist; /* distance of matched string */ 1078168404Spjd int lc; /* match length or unmatched char (if dist == 0) */ 1079168404Spjd unsigned lx = 0; /* running index in l_buf */ 1080168404Spjd unsigned code; /* the code to send */ 1081168404Spjd int extra; /* number of extra bits to send */ 1082168404Spjd 1083168404Spjd if (s->last_lit != 0) do { 1084168404Spjd dist = s->d_buf[lx]; 1085168404Spjd lc = s->l_buf[lx++]; 1086168404Spjd if (dist == 0) { 1087168404Spjd send_code(s, lc, ltree); /* send a literal byte */ 1088168404Spjd Tracecv(isgraph(lc), (stderr," '%c' ", lc)); 1089168404Spjd } else { 1090168404Spjd /* Here, lc is the match length - MIN_MATCH */ 1091168404Spjd code = _length_code[lc]; 1092168404Spjd send_code(s, code+LITERALS+1, ltree); /* send the length code */ 1093168404Spjd extra = extra_lbits[code]; 1094168404Spjd if (extra != 0) { 1095168404Spjd lc -= base_length[code]; 1096168404Spjd send_bits(s, lc, extra); /* send the extra length bits */ 1097168404Spjd } 1098168404Spjd dist--; /* dist is now the match distance - 1 */ 1099168404Spjd code = d_code(dist); 1100168404Spjd Assert (code < D_CODES, "bad d_code"); 1101168404Spjd 1102168404Spjd send_code(s, code, dtree); /* send the distance code */ 1103168404Spjd extra = extra_dbits[code]; 1104168404Spjd if (extra != 0) { 1105168404Spjd dist -= base_dist[code]; 1106168404Spjd send_bits(s, dist, extra); /* send the extra distance bits */ 1107168404Spjd } 1108168404Spjd } /* literal or match pair ? */ 1109168404Spjd 1110168404Spjd /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ 1111168404Spjd Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, 1112168404Spjd "pendingBuf overflow"); 1113168404Spjd 1114168404Spjd } while (lx < s->last_lit); 1115168404Spjd 1116168404Spjd send_code(s, END_BLOCK, ltree); 1117168404Spjd s->last_eob_len = ltree[END_BLOCK].Len; 1118168404Spjd} 1119168404Spjd 1120168404Spjd/* =========================================================================== 1121168404Spjd * Set the data type to BINARY or TEXT, using a crude approximation: 1122168404Spjd * set it to Z_TEXT if all symbols are either printable characters (33 to 255) 1123168404Spjd * or white spaces (9 to 13, or 32); or set it to Z_BINARY otherwise. 1124168404Spjd * IN assertion: the fields Freq of dyn_ltree are set. 1125168404Spjd */ 1126168404Spjdlocal void set_data_type(s) 1127168404Spjd deflate_state *s; 1128168404Spjd{ 1129168404Spjd int n; 1130168404Spjd 1131168404Spjd for (n = 0; n < 9; n++) 1132168404Spjd if (s->dyn_ltree[n].Freq != 0) 1133168404Spjd break; 1134168404Spjd if (n == 9) 1135168404Spjd for (n = 14; n < 32; n++) 1136168404Spjd if (s->dyn_ltree[n].Freq != 0) 1137168404Spjd break; 1138168404Spjd s->strm->data_type = (n == 32) ? Z_TEXT : Z_BINARY; 1139168404Spjd} 1140168404Spjd 1141168404Spjd/* =========================================================================== 1142168404Spjd * Reverse the first len bits of a code, using straightforward code (a faster 1143168404Spjd * method would use a table) 1144168404Spjd * IN assertion: 1 <= len <= 15 1145168404Spjd */ 1146168404Spjdlocal unsigned bi_reverse(code, len) 1147168404Spjd unsigned code; /* the value to invert */ 1148168404Spjd int len; /* its bit length */ 1149168404Spjd{ 1150168404Spjd register unsigned res = 0; 1151168404Spjd do { 1152168404Spjd res |= code & 1; 1153168404Spjd code >>= 1, res <<= 1; 1154168404Spjd } while (--len > 0); 1155168404Spjd return res >> 1; 1156168404Spjd} 1157168404Spjd 1158168404Spjd/* =========================================================================== 1159168404Spjd * Flush the bit buffer, keeping at most 7 bits in it. 1160168404Spjd */ 1161168404Spjdlocal void bi_flush(s) 1162168404Spjd deflate_state *s; 1163168404Spjd{ 1164168404Spjd if (s->bi_valid == 16) { 1165168404Spjd put_short(s, s->bi_buf); 1166168404Spjd s->bi_buf = 0; 1167168404Spjd s->bi_valid = 0; 1168168404Spjd } else if (s->bi_valid >= 8) { 1169168404Spjd put_byte(s, (Byte)s->bi_buf); 1170168404Spjd s->bi_buf >>= 8; 1171168404Spjd s->bi_valid -= 8; 1172168404Spjd } 1173168404Spjd} 1174168404Spjd 1175168404Spjd/* =========================================================================== 1176168404Spjd * Flush the bit buffer and align the output on a byte boundary 1177168404Spjd */ 1178168404Spjdlocal void bi_windup(s) 1179168404Spjd deflate_state *s; 1180168404Spjd{ 1181168404Spjd if (s->bi_valid > 8) { 1182168404Spjd put_short(s, s->bi_buf); 1183168404Spjd } else if (s->bi_valid > 0) { 1184168404Spjd put_byte(s, (Byte)s->bi_buf); 1185168404Spjd } 1186168404Spjd s->bi_buf = 0; 1187168404Spjd s->bi_valid = 0; 1188168404Spjd#ifdef DEBUG 1189168404Spjd s->bits_sent = (s->bits_sent+7) & ~7; 1190168404Spjd#endif 1191168404Spjd} 1192168404Spjd 1193168404Spjd/* =========================================================================== 1194168404Spjd * Copy a stored block, storing first the length and its 1195168404Spjd * one's complement if requested. 1196168404Spjd */ 1197168404Spjdlocal void copy_block(s, buf, len, header) 1198168404Spjd deflate_state *s; 1199168404Spjd charf *buf; /* the input data */ 1200168404Spjd unsigned len; /* its length */ 1201168404Spjd int header; /* true if block header must be written */ 1202168404Spjd{ 1203168404Spjd bi_windup(s); /* align on byte boundary */ 1204168404Spjd s->last_eob_len = 8; /* enough lookahead for inflate */ 1205168404Spjd 1206168404Spjd if (header) { 1207168404Spjd put_short(s, (ush)len); 1208168404Spjd put_short(s, (ush)~len); 1209168404Spjd#ifdef DEBUG 1210168404Spjd s->bits_sent += 2*16; 1211168404Spjd#endif 1212168404Spjd } 1213168404Spjd#ifdef DEBUG 1214168404Spjd s->bits_sent += (ulg)len<<3; 1215168404Spjd#endif 1216168404Spjd while (len--) { 1217168404Spjd put_byte(s, *buf++); 1218168404Spjd } 1219168404Spjd} 1220