117651Speter/* trees.c -- output deflated data using Huffman coding 2313796Sdelphij * Copyright (C) 1995-2017 Jean-loup Gailly 3205194Sdelphij * detect_data_type() function provided freely by Cosmin Truta, 2006 4131377Stjr * For conditions of distribution and use, see copyright notice in zlib.h 517651Speter */ 617651Speter 717651Speter/* 817651Speter * ALGORITHM 917651Speter * 1017651Speter * The "deflation" process uses several Huffman trees. The more 1117651Speter * common source values are represented by shorter bit sequences. 1217651Speter * 1317651Speter * Each code tree is stored in a compressed form which is itself 1417651Speter * a Huffman encoding of the lengths of all the code strings (in 1517651Speter * ascending order by source values). The actual code strings are 1617651Speter * reconstructed from the lengths in the inflate process, as described 1717651Speter * in the deflate specification. 1817651Speter * 1917651Speter * REFERENCES 2017651Speter * 2117651Speter * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". 2217651Speter * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc 2317651Speter * 2417651Speter * Storer, James A. 2517651Speter * Data Compression: Methods and Theory, pp. 49-50. 2617651Speter * Computer Science Press, 1988. ISBN 0-7167-8156-5. 2717651Speter * 2817651Speter * Sedgewick, R. 2917651Speter * Algorithms, p290. 3017651Speter * Addison-Wesley, 1983. ISBN 0-201-06672-6. 3117651Speter */ 3217651Speter 3333904Ssteve/* @(#) $Id$ */ 3417651Speter 3533904Ssteve/* #define GEN_TREES_H */ 3633904Ssteve 3717651Speter#include "deflate.h" 3817651Speter 39313796Sdelphij#ifdef ZLIB_DEBUG 4017651Speter# include <ctype.h> 4117651Speter#endif 4217651Speter 4317651Speter/* =========================================================================== 4417651Speter * Constants 4517651Speter */ 4617651Speter 4717651Speter#define MAX_BL_BITS 7 4817651Speter/* Bit length codes must not exceed MAX_BL_BITS bits */ 4917651Speter 5017651Speter#define END_BLOCK 256 5117651Speter/* end of block literal code */ 5217651Speter 5317651Speter#define REP_3_6 16 5417651Speter/* repeat previous bit length 3-6 times (2 bits of repeat count) */ 5517651Speter 5617651Speter#define REPZ_3_10 17 5717651Speter/* repeat a zero length 3-10 times (3 bits of repeat count) */ 5817651Speter 5917651Speter#define REPZ_11_138 18 6017651Speter/* repeat a zero length 11-138 times (7 bits of repeat count) */ 6117651Speter 6233904Sstevelocal const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ 6317651Speter = {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}; 6417651Speter 6533904Sstevelocal const int extra_dbits[D_CODES] /* extra bits for each distance code */ 6617651Speter = {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}; 6717651Speter 6833904Sstevelocal const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ 6917651Speter = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; 7017651Speter 7133904Sstevelocal const uch bl_order[BL_CODES] 7217651Speter = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; 7317651Speter/* The lengths of the bit length codes are sent in order of decreasing 7417651Speter * probability, to avoid transmitting the lengths for unused bit length codes. 7517651Speter */ 7617651Speter 7717651Speter/* =========================================================================== 7817651Speter * Local data. These are initialized only once. 7917651Speter */ 8017651Speter 8133904Ssteve#define DIST_CODE_LEN 512 /* see definition of array dist_code below */ 8233904Ssteve 8333904Ssteve#if defined(GEN_TREES_H) || !defined(STDC) 8433904Ssteve/* non ANSI compilers may not accept trees.h */ 8533904Ssteve 8617651Speterlocal ct_data static_ltree[L_CODES+2]; 8717651Speter/* The static literal tree. Since the bit lengths are imposed, there is no 8817651Speter * need for the L_CODES extra codes used during heap construction. However 8917651Speter * The codes 286 and 287 are needed to build a canonical tree (see _tr_init 9017651Speter * below). 9117651Speter */ 9217651Speter 9317651Speterlocal ct_data static_dtree[D_CODES]; 9417651Speter/* The static distance tree. (Actually a trivial tree since all codes use 9517651Speter * 5 bits.) 9617651Speter */ 9717651Speter 9833904Ssteveuch _dist_code[DIST_CODE_LEN]; 9933904Ssteve/* Distance codes. The first 256 values correspond to the distances 10017651Speter * 3 .. 258, the last 256 values correspond to the top 8 bits of 10117651Speter * the 15 bit distances. 10217651Speter */ 10317651Speter 10433904Ssteveuch _length_code[MAX_MATCH-MIN_MATCH+1]; 10517651Speter/* length code for each normalized match length (0 == MIN_MATCH) */ 10617651Speter 10717651Speterlocal int base_length[LENGTH_CODES]; 10817651Speter/* First normalized length for each code (0 = MIN_MATCH) */ 10917651Speter 11017651Speterlocal int base_dist[D_CODES]; 11117651Speter/* First normalized distance for each code (0 = distance of 1) */ 11217651Speter 11333904Ssteve#else 11433904Ssteve# include "trees.h" 11533904Ssteve#endif /* GEN_TREES_H */ 11633904Ssteve 11717651Speterstruct static_tree_desc_s { 11833904Ssteve const ct_data *static_tree; /* static tree or NULL */ 11933904Ssteve const intf *extra_bits; /* extra bits for each code or NULL */ 12017651Speter int extra_base; /* base index for extra_bits */ 12117651Speter int elems; /* max number of elements in the tree */ 12217651Speter int max_length; /* max bit length for the codes */ 12317651Speter}; 12417651Speter 125313796Sdelphijlocal const static_tree_desc static_l_desc = 12617651Speter{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; 12717651Speter 128313796Sdelphijlocal const static_tree_desc static_d_desc = 12917651Speter{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; 13017651Speter 131313796Sdelphijlocal const static_tree_desc static_bl_desc = 13233904Ssteve{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; 13317651Speter 13417651Speter/* =========================================================================== 13517651Speter * Local (static) routines in this file. 13617651Speter */ 13717651Speter 13817651Speterlocal void tr_static_init OF((void)); 13917651Speterlocal void init_block OF((deflate_state *s)); 14017651Speterlocal void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); 14117651Speterlocal void gen_bitlen OF((deflate_state *s, tree_desc *desc)); 14217651Speterlocal void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); 14317651Speterlocal void build_tree OF((deflate_state *s, tree_desc *desc)); 14417651Speterlocal void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); 14517651Speterlocal void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); 14617651Speterlocal int build_bl_tree OF((deflate_state *s)); 14717651Speterlocal void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, 14817651Speter int blcodes)); 149250224Sdelphijlocal void compress_block OF((deflate_state *s, const ct_data *ltree, 150250224Sdelphij const ct_data *dtree)); 151205194Sdelphijlocal int detect_data_type OF((deflate_state *s)); 15217651Speterlocal unsigned bi_reverse OF((unsigned value, int length)); 15317651Speterlocal void bi_windup OF((deflate_state *s)); 15417651Speterlocal void bi_flush OF((deflate_state *s)); 15517651Speter 15633904Ssteve#ifdef GEN_TREES_H 15733904Sstevelocal void gen_trees_header OF((void)); 15833904Ssteve#endif 15933904Ssteve 160313796Sdelphij#ifndef ZLIB_DEBUG 16117651Speter# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) 16217651Speter /* Send a code of the given tree. c and tree must not have side effects */ 16317651Speter 164313796Sdelphij#else /* !ZLIB_DEBUG */ 16517651Speter# define send_code(s, c, tree) \ 16633904Ssteve { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ 16717651Speter send_bits(s, tree[c].Code, tree[c].Len); } 16817651Speter#endif 16917651Speter 17017651Speter/* =========================================================================== 17117651Speter * Output a short LSB first on the stream. 17217651Speter * IN assertion: there is enough room in pendingBuf. 17317651Speter */ 17417651Speter#define put_short(s, w) { \ 17517651Speter put_byte(s, (uch)((w) & 0xff)); \ 17617651Speter put_byte(s, (uch)((ush)(w) >> 8)); \ 17717651Speter} 17817651Speter 17917651Speter/* =========================================================================== 18017651Speter * Send a value on a given number of bits. 18117651Speter * IN assertion: length <= 16 and value fits in length bits. 18217651Speter */ 183313796Sdelphij#ifdef ZLIB_DEBUG 18417651Speterlocal void send_bits OF((deflate_state *s, int value, int length)); 18517651Speter 18617651Speterlocal void send_bits(s, value, length) 18717651Speter deflate_state *s; 18817651Speter int value; /* value to send */ 18917651Speter int length; /* number of bits */ 19017651Speter{ 19117651Speter Tracevv((stderr," l %2d v %4x ", length, value)); 19217651Speter Assert(length > 0 && length <= 15, "invalid length"); 19317651Speter s->bits_sent += (ulg)length; 19417651Speter 19517651Speter /* If not enough room in bi_buf, use (valid) bits from bi_buf and 19617651Speter * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) 19717651Speter * unused bits in value. 19817651Speter */ 19917651Speter if (s->bi_valid > (int)Buf_size - length) { 200205194Sdelphij s->bi_buf |= (ush)value << s->bi_valid; 20117651Speter put_short(s, s->bi_buf); 20217651Speter s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); 20317651Speter s->bi_valid += length - Buf_size; 20417651Speter } else { 205205194Sdelphij s->bi_buf |= (ush)value << s->bi_valid; 20617651Speter s->bi_valid += length; 20717651Speter } 20817651Speter} 209313796Sdelphij#else /* !ZLIB_DEBUG */ 21017651Speter 21117651Speter#define send_bits(s, value, length) \ 21217651Speter{ int len = length;\ 21317651Speter if (s->bi_valid > (int)Buf_size - len) {\ 214313796Sdelphij int val = (int)value;\ 215205194Sdelphij s->bi_buf |= (ush)val << s->bi_valid;\ 21617651Speter put_short(s, s->bi_buf);\ 21717651Speter s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ 21817651Speter s->bi_valid += len - Buf_size;\ 21917651Speter } else {\ 220205194Sdelphij s->bi_buf |= (ush)(value) << s->bi_valid;\ 22117651Speter s->bi_valid += len;\ 22217651Speter }\ 22317651Speter} 224313796Sdelphij#endif /* ZLIB_DEBUG */ 22517651Speter 22617651Speter 22717651Speter/* the arguments must not have side effects */ 22817651Speter 22917651Speter/* =========================================================================== 23033904Ssteve * Initialize the various 'constant' tables. 23117651Speter */ 23217651Speterlocal void tr_static_init() 23317651Speter{ 23433904Ssteve#if defined(GEN_TREES_H) || !defined(STDC) 23517651Speter static int static_init_done = 0; 23617651Speter int n; /* iterates over tree elements */ 23717651Speter int bits; /* bit counter */ 23817651Speter int length; /* length value */ 23917651Speter int code; /* code value */ 24017651Speter int dist; /* distance index */ 24117651Speter ush bl_count[MAX_BITS+1]; 24217651Speter /* number of codes at each bit length for an optimal tree */ 24317651Speter 24417651Speter if (static_init_done) return; 24517651Speter 24642468Speter /* For some embedded targets, global variables are not initialized: */ 247205194Sdelphij#ifdef NO_INIT_GLOBAL_POINTERS 24842468Speter static_l_desc.static_tree = static_ltree; 24942468Speter static_l_desc.extra_bits = extra_lbits; 25042468Speter static_d_desc.static_tree = static_dtree; 25142468Speter static_d_desc.extra_bits = extra_dbits; 25242468Speter static_bl_desc.extra_bits = extra_blbits; 253205194Sdelphij#endif 25442468Speter 25517651Speter /* Initialize the mapping length (0..255) -> length code (0..28) */ 25617651Speter length = 0; 25717651Speter for (code = 0; code < LENGTH_CODES-1; code++) { 25817651Speter base_length[code] = length; 25917651Speter for (n = 0; n < (1<<extra_lbits[code]); n++) { 26033904Ssteve _length_code[length++] = (uch)code; 26117651Speter } 26217651Speter } 26317651Speter Assert (length == 256, "tr_static_init: length != 256"); 26417651Speter /* Note that the length 255 (match length 258) can be represented 26517651Speter * in two different ways: code 284 + 5 bits or code 285, so we 26617651Speter * overwrite length_code[255] to use the best encoding: 26717651Speter */ 26833904Ssteve _length_code[length-1] = (uch)code; 26917651Speter 27017651Speter /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ 27117651Speter dist = 0; 27217651Speter for (code = 0 ; code < 16; code++) { 27317651Speter base_dist[code] = dist; 27417651Speter for (n = 0; n < (1<<extra_dbits[code]); n++) { 27533904Ssteve _dist_code[dist++] = (uch)code; 27617651Speter } 27717651Speter } 27817651Speter Assert (dist == 256, "tr_static_init: dist != 256"); 27917651Speter dist >>= 7; /* from now on, all distances are divided by 128 */ 28017651Speter for ( ; code < D_CODES; code++) { 28117651Speter base_dist[code] = dist << 7; 28217651Speter for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { 28333904Ssteve _dist_code[256 + dist++] = (uch)code; 28417651Speter } 28517651Speter } 28617651Speter Assert (dist == 256, "tr_static_init: 256+dist != 512"); 28717651Speter 28817651Speter /* Construct the codes of the static literal tree */ 28917651Speter for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; 29017651Speter n = 0; 29117651Speter while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; 29217651Speter while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; 29317651Speter while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; 29417651Speter while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; 29517651Speter /* Codes 286 and 287 do not exist, but we must include them in the 29617651Speter * tree construction to get a canonical Huffman tree (longest code 29717651Speter * all ones) 29817651Speter */ 29917651Speter gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); 30017651Speter 30117651Speter /* The static distance tree is trivial: */ 30217651Speter for (n = 0; n < D_CODES; n++) { 30317651Speter static_dtree[n].Len = 5; 30417651Speter static_dtree[n].Code = bi_reverse((unsigned)n, 5); 30517651Speter } 30617651Speter static_init_done = 1; 30733904Ssteve 30833904Ssteve# ifdef GEN_TREES_H 30933904Ssteve gen_trees_header(); 31033904Ssteve# endif 31133904Ssteve#endif /* defined(GEN_TREES_H) || !defined(STDC) */ 31217651Speter} 31317651Speter 31417651Speter/* =========================================================================== 31533904Ssteve * Genererate the file trees.h describing the static trees. 31633904Ssteve */ 31733904Ssteve#ifdef GEN_TREES_H 318313796Sdelphij# ifndef ZLIB_DEBUG 31933904Ssteve# include <stdio.h> 32033904Ssteve# endif 32133904Ssteve 32233904Ssteve# define SEPARATOR(i, last, width) \ 32333904Ssteve ((i) == (last)? "\n};\n\n" : \ 32433904Ssteve ((i) % (width) == (width)-1 ? ",\n" : ", ")) 32533904Ssteve 32633904Sstevevoid gen_trees_header() 32733904Ssteve{ 32833904Ssteve FILE *header = fopen("trees.h", "w"); 32933904Ssteve int i; 33033904Ssteve 33133904Ssteve Assert (header != NULL, "Can't open trees.h"); 33233904Ssteve fprintf(header, 333131377Stjr "/* header created automatically with -DGEN_TREES_H */\n\n"); 33433904Ssteve 33533904Ssteve fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); 33633904Ssteve for (i = 0; i < L_CODES+2; i++) { 337131377Stjr fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, 338131377Stjr static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); 33933904Ssteve } 34033904Ssteve 34133904Ssteve fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); 34233904Ssteve for (i = 0; i < D_CODES; i++) { 343131377Stjr fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, 344131377Stjr static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); 34533904Ssteve } 34633904Ssteve 347206905Sdelphij fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n"); 34833904Ssteve for (i = 0; i < DIST_CODE_LEN; i++) { 349131377Stjr fprintf(header, "%2u%s", _dist_code[i], 350131377Stjr SEPARATOR(i, DIST_CODE_LEN-1, 20)); 35133904Ssteve } 35233904Ssteve 353206905Sdelphij fprintf(header, 354206905Sdelphij "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); 35533904Ssteve for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { 356131377Stjr fprintf(header, "%2u%s", _length_code[i], 357131377Stjr SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); 35833904Ssteve } 35933904Ssteve 36033904Ssteve fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); 36133904Ssteve for (i = 0; i < LENGTH_CODES; i++) { 362131377Stjr fprintf(header, "%1u%s", base_length[i], 363131377Stjr SEPARATOR(i, LENGTH_CODES-1, 20)); 36433904Ssteve } 36533904Ssteve 36633904Ssteve fprintf(header, "local const int base_dist[D_CODES] = {\n"); 36733904Ssteve for (i = 0; i < D_CODES; i++) { 368131377Stjr fprintf(header, "%5u%s", base_dist[i], 369131377Stjr SEPARATOR(i, D_CODES-1, 10)); 37033904Ssteve } 37133904Ssteve 37233904Ssteve fclose(header); 37333904Ssteve} 37433904Ssteve#endif /* GEN_TREES_H */ 37533904Ssteve 37633904Ssteve/* =========================================================================== 37717651Speter * Initialize the tree data structures for a new zlib stream. 37817651Speter */ 379206905Sdelphijvoid ZLIB_INTERNAL _tr_init(s) 38017651Speter deflate_state *s; 38117651Speter{ 38217651Speter tr_static_init(); 38317651Speter 38417651Speter s->l_desc.dyn_tree = s->dyn_ltree; 38517651Speter s->l_desc.stat_desc = &static_l_desc; 38617651Speter 38717651Speter s->d_desc.dyn_tree = s->dyn_dtree; 38817651Speter s->d_desc.stat_desc = &static_d_desc; 38917651Speter 39017651Speter s->bl_desc.dyn_tree = s->bl_tree; 39117651Speter s->bl_desc.stat_desc = &static_bl_desc; 39217651Speter 39317651Speter s->bi_buf = 0; 39417651Speter s->bi_valid = 0; 395313796Sdelphij#ifdef ZLIB_DEBUG 39642468Speter s->compressed_len = 0L; 39717651Speter s->bits_sent = 0L; 39817651Speter#endif 39917651Speter 40017651Speter /* Initialize the first block of the first file: */ 40117651Speter init_block(s); 40217651Speter} 40317651Speter 40417651Speter/* =========================================================================== 40517651Speter * Initialize a new block. 40617651Speter */ 40717651Speterlocal void init_block(s) 40817651Speter deflate_state *s; 40917651Speter{ 41017651Speter int n; /* iterates over tree elements */ 41117651Speter 41217651Speter /* Initialize the trees. */ 41317651Speter for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; 41417651Speter for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; 41517651Speter for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; 41617651Speter 41717651Speter s->dyn_ltree[END_BLOCK].Freq = 1; 41817651Speter s->opt_len = s->static_len = 0L; 41917651Speter s->last_lit = s->matches = 0; 42017651Speter} 42117651Speter 42217651Speter#define SMALLEST 1 42317651Speter/* Index within the heap array of least frequent node in the Huffman tree */ 42417651Speter 42517651Speter 42617651Speter/* =========================================================================== 42717651Speter * Remove the smallest element from the heap and recreate the heap with 42817651Speter * one less element. Updates heap and heap_len. 42917651Speter */ 43017651Speter#define pqremove(s, tree, top) \ 43117651Speter{\ 43217651Speter top = s->heap[SMALLEST]; \ 43317651Speter s->heap[SMALLEST] = s->heap[s->heap_len--]; \ 43417651Speter pqdownheap(s, tree, SMALLEST); \ 43517651Speter} 43617651Speter 43717651Speter/* =========================================================================== 43817651Speter * Compares to subtrees, using the tree depth as tie breaker when 43917651Speter * the subtrees have equal frequency. This minimizes the worst case length. 44017651Speter */ 44117651Speter#define smaller(tree, n, m, depth) \ 44217651Speter (tree[n].Freq < tree[m].Freq || \ 44317651Speter (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) 44417651Speter 44517651Speter/* =========================================================================== 44617651Speter * Restore the heap property by moving down the tree starting at node k, 44717651Speter * exchanging a node with the smallest of its two sons if necessary, stopping 44817651Speter * when the heap property is re-established (each father smaller than its 44917651Speter * two sons). 45017651Speter */ 45117651Speterlocal void pqdownheap(s, tree, k) 45217651Speter deflate_state *s; 45317651Speter ct_data *tree; /* the tree to restore */ 45417651Speter int k; /* node to move down */ 45517651Speter{ 45617651Speter int v = s->heap[k]; 45717651Speter int j = k << 1; /* left son of k */ 45817651Speter while (j <= s->heap_len) { 45917651Speter /* Set j to the smallest of the two sons: */ 46017651Speter if (j < s->heap_len && 46117651Speter smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { 46217651Speter j++; 46317651Speter } 46417651Speter /* Exit if v is smaller than both sons */ 46517651Speter if (smaller(tree, v, s->heap[j], s->depth)) break; 46617651Speter 46717651Speter /* Exchange v with the smallest son */ 46817651Speter s->heap[k] = s->heap[j]; k = j; 46917651Speter 47017651Speter /* And continue down the tree, setting j to the left son of k */ 47117651Speter j <<= 1; 47217651Speter } 47317651Speter s->heap[k] = v; 47417651Speter} 47517651Speter 47617651Speter/* =========================================================================== 47717651Speter * Compute the optimal bit lengths for a tree and update the total bit length 47817651Speter * for the current block. 47917651Speter * IN assertion: the fields freq and dad are set, heap[heap_max] and 48017651Speter * above are the tree nodes sorted by increasing frequency. 48117651Speter * OUT assertions: the field len is set to the optimal bit length, the 48217651Speter * array bl_count contains the frequencies for each bit length. 48317651Speter * The length opt_len is updated; static_len is also updated if stree is 48417651Speter * not null. 48517651Speter */ 48617651Speterlocal void gen_bitlen(s, desc) 48717651Speter deflate_state *s; 48817651Speter tree_desc *desc; /* the tree descriptor */ 48917651Speter{ 49033904Ssteve ct_data *tree = desc->dyn_tree; 49133904Ssteve int max_code = desc->max_code; 49233904Ssteve const ct_data *stree = desc->stat_desc->static_tree; 49333904Ssteve const intf *extra = desc->stat_desc->extra_bits; 49433904Ssteve int base = desc->stat_desc->extra_base; 49533904Ssteve int max_length = desc->stat_desc->max_length; 49617651Speter int h; /* heap index */ 49717651Speter int n, m; /* iterate over the tree elements */ 49817651Speter int bits; /* bit length */ 49917651Speter int xbits; /* extra bits */ 50017651Speter ush f; /* frequency */ 50117651Speter int overflow = 0; /* number of elements with bit length too large */ 50217651Speter 50317651Speter for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; 50417651Speter 50517651Speter /* In a first pass, compute the optimal bit lengths (which may 50617651Speter * overflow in the case of the bit length tree). 50717651Speter */ 50817651Speter tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ 50917651Speter 51017651Speter for (h = s->heap_max+1; h < HEAP_SIZE; h++) { 51117651Speter n = s->heap[h]; 51217651Speter bits = tree[tree[n].Dad].Len + 1; 51317651Speter if (bits > max_length) bits = max_length, overflow++; 51417651Speter tree[n].Len = (ush)bits; 51517651Speter /* We overwrite tree[n].Dad which is no longer needed */ 51617651Speter 51717651Speter if (n > max_code) continue; /* not a leaf node */ 51817651Speter 51917651Speter s->bl_count[bits]++; 52017651Speter xbits = 0; 52117651Speter if (n >= base) xbits = extra[n-base]; 52217651Speter f = tree[n].Freq; 523313796Sdelphij s->opt_len += (ulg)f * (unsigned)(bits + xbits); 524313796Sdelphij if (stree) s->static_len += (ulg)f * (unsigned)(stree[n].Len + xbits); 52517651Speter } 52617651Speter if (overflow == 0) return; 52717651Speter 528313796Sdelphij Tracev((stderr,"\nbit length overflow\n")); 52917651Speter /* This happens for example on obj2 and pic of the Calgary corpus */ 53017651Speter 53117651Speter /* Find the first bit length which could increase: */ 53217651Speter do { 53317651Speter bits = max_length-1; 53417651Speter while (s->bl_count[bits] == 0) bits--; 53517651Speter s->bl_count[bits]--; /* move one leaf down the tree */ 53617651Speter s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ 53717651Speter s->bl_count[max_length]--; 53817651Speter /* The brother of the overflow item also moves one step up, 53917651Speter * but this does not affect bl_count[max_length] 54017651Speter */ 54117651Speter overflow -= 2; 54217651Speter } while (overflow > 0); 54317651Speter 54417651Speter /* Now recompute all bit lengths, scanning in increasing frequency. 54517651Speter * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all 54617651Speter * lengths instead of fixing only the wrong ones. This idea is taken 54717651Speter * from 'ar' written by Haruhiko Okumura.) 54817651Speter */ 54917651Speter for (bits = max_length; bits != 0; bits--) { 55017651Speter n = s->bl_count[bits]; 55117651Speter while (n != 0) { 55217651Speter m = s->heap[--h]; 55317651Speter if (m > max_code) continue; 554157043Sdes if ((unsigned) tree[m].Len != (unsigned) bits) { 555313796Sdelphij Tracev((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); 556313796Sdelphij s->opt_len += ((ulg)bits - tree[m].Len) * tree[m].Freq; 55717651Speter tree[m].Len = (ush)bits; 55817651Speter } 55917651Speter n--; 56017651Speter } 56117651Speter } 56217651Speter} 56317651Speter 56417651Speter/* =========================================================================== 56517651Speter * Generate the codes for a given tree and bit counts (which need not be 56617651Speter * optimal). 56717651Speter * IN assertion: the array bl_count contains the bit length statistics for 56817651Speter * the given tree and the field len is set for all tree elements. 56917651Speter * OUT assertion: the field code is set for all tree elements of non 57017651Speter * zero code length. 57117651Speter */ 57217651Speterlocal void gen_codes (tree, max_code, bl_count) 57317651Speter ct_data *tree; /* the tree to decorate */ 57417651Speter int max_code; /* largest code with non zero frequency */ 57517651Speter ushf *bl_count; /* number of codes at each bit length */ 57617651Speter{ 57717651Speter ush next_code[MAX_BITS+1]; /* next code value for each bit length */ 578313796Sdelphij unsigned code = 0; /* running code value */ 57917651Speter int bits; /* bit index */ 58017651Speter int n; /* code index */ 58117651Speter 58217651Speter /* The distribution counts are first used to generate the code values 58317651Speter * without bit reversal. 58417651Speter */ 58517651Speter for (bits = 1; bits <= MAX_BITS; bits++) { 586313796Sdelphij code = (code + bl_count[bits-1]) << 1; 587313796Sdelphij next_code[bits] = (ush)code; 58817651Speter } 58917651Speter /* Check that the bit counts in bl_count are consistent. The last code 59017651Speter * must be all ones. 59117651Speter */ 59217651Speter Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, 59317651Speter "inconsistent bit counts"); 59417651Speter Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); 59517651Speter 59617651Speter for (n = 0; n <= max_code; n++) { 59717651Speter int len = tree[n].Len; 59817651Speter if (len == 0) continue; 59917651Speter /* Now reverse the bits */ 600313796Sdelphij tree[n].Code = (ush)bi_reverse(next_code[len]++, len); 60117651Speter 60217651Speter Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", 60317651Speter n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); 60417651Speter } 60517651Speter} 60617651Speter 60717651Speter/* =========================================================================== 60817651Speter * Construct one Huffman tree and assigns the code bit strings and lengths. 60917651Speter * Update the total bit length for the current block. 61017651Speter * IN assertion: the field freq is set for all tree elements. 61117651Speter * OUT assertions: the fields len and code are set to the optimal bit length 61217651Speter * and corresponding code. The length opt_len is updated; static_len is 61317651Speter * also updated if stree is not null. The field max_code is set. 61417651Speter */ 61517651Speterlocal void build_tree(s, desc) 61617651Speter deflate_state *s; 61717651Speter tree_desc *desc; /* the tree descriptor */ 61817651Speter{ 61933904Ssteve ct_data *tree = desc->dyn_tree; 62033904Ssteve const ct_data *stree = desc->stat_desc->static_tree; 62133904Ssteve int elems = desc->stat_desc->elems; 62217651Speter int n, m; /* iterate over heap elements */ 62317651Speter int max_code = -1; /* largest code with non zero frequency */ 62417651Speter int node; /* new node being created */ 62517651Speter 62617651Speter /* Construct the initial heap, with least frequent element in 62717651Speter * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. 62817651Speter * heap[0] is not used. 62917651Speter */ 63017651Speter s->heap_len = 0, s->heap_max = HEAP_SIZE; 63117651Speter 63217651Speter for (n = 0; n < elems; n++) { 63317651Speter if (tree[n].Freq != 0) { 63417651Speter s->heap[++(s->heap_len)] = max_code = n; 63517651Speter s->depth[n] = 0; 63617651Speter } else { 63717651Speter tree[n].Len = 0; 63817651Speter } 63917651Speter } 64017651Speter 64117651Speter /* The pkzip format requires that at least one distance code exists, 64217651Speter * and that at least one bit should be sent even if there is only one 64317651Speter * possible code. So to avoid special checks later on we force at least 64417651Speter * two codes of non zero frequency. 64517651Speter */ 64617651Speter while (s->heap_len < 2) { 64717651Speter node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); 64817651Speter tree[node].Freq = 1; 64917651Speter s->depth[node] = 0; 65017651Speter s->opt_len--; if (stree) s->static_len -= stree[node].Len; 65117651Speter /* node is 0 or 1 so it does not have extra bits */ 65217651Speter } 65317651Speter desc->max_code = max_code; 65417651Speter 65517651Speter /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, 65617651Speter * establish sub-heaps of increasing lengths: 65717651Speter */ 65817651Speter for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); 65917651Speter 66017651Speter /* Construct the Huffman tree by repeatedly combining the least two 66117651Speter * frequent nodes. 66217651Speter */ 66317651Speter node = elems; /* next internal node of the tree */ 66417651Speter do { 66517651Speter pqremove(s, tree, n); /* n = node of least frequency */ 66617651Speter m = s->heap[SMALLEST]; /* m = node of next least frequency */ 66717651Speter 66817651Speter s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ 66917651Speter s->heap[--(s->heap_max)] = m; 67017651Speter 67117651Speter /* Create a new node father of n and m */ 67217651Speter tree[node].Freq = tree[n].Freq + tree[m].Freq; 673131377Stjr s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? 674131377Stjr s->depth[n] : s->depth[m]) + 1); 67517651Speter tree[n].Dad = tree[m].Dad = (ush)node; 67617651Speter#ifdef DUMP_BL_TREE 67717651Speter if (tree == s->bl_tree) { 67817651Speter fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", 67917651Speter node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); 68017651Speter } 68117651Speter#endif 68217651Speter /* and insert the new node in the heap */ 68317651Speter s->heap[SMALLEST] = node++; 68417651Speter pqdownheap(s, tree, SMALLEST); 68517651Speter 68617651Speter } while (s->heap_len >= 2); 68717651Speter 68817651Speter s->heap[--(s->heap_max)] = s->heap[SMALLEST]; 68917651Speter 69017651Speter /* At this point, the fields freq and dad are set. We can now 69117651Speter * generate the bit lengths. 69217651Speter */ 69317651Speter gen_bitlen(s, (tree_desc *)desc); 69417651Speter 69517651Speter /* The field len is now set, we can generate the bit codes */ 69617651Speter gen_codes ((ct_data *)tree, max_code, s->bl_count); 69717651Speter} 69817651Speter 69917651Speter/* =========================================================================== 70017651Speter * Scan a literal or distance tree to determine the frequencies of the codes 70117651Speter * in the bit length tree. 70217651Speter */ 70317651Speterlocal void scan_tree (s, tree, max_code) 70417651Speter deflate_state *s; 70517651Speter ct_data *tree; /* the tree to be scanned */ 70617651Speter int max_code; /* and its largest code of non zero frequency */ 70717651Speter{ 70817651Speter int n; /* iterates over all tree elements */ 70917651Speter int prevlen = -1; /* last emitted length */ 71017651Speter int curlen; /* length of current code */ 71117651Speter int nextlen = tree[0].Len; /* length of next code */ 71217651Speter int count = 0; /* repeat count of the current code */ 71317651Speter int max_count = 7; /* max repeat count */ 71417651Speter int min_count = 4; /* min repeat count */ 71517651Speter 71617651Speter if (nextlen == 0) max_count = 138, min_count = 3; 71717651Speter tree[max_code+1].Len = (ush)0xffff; /* guard */ 71817651Speter 71917651Speter for (n = 0; n <= max_code; n++) { 72017651Speter curlen = nextlen; nextlen = tree[n+1].Len; 72117651Speter if (++count < max_count && curlen == nextlen) { 72217651Speter continue; 72317651Speter } else if (count < min_count) { 72417651Speter s->bl_tree[curlen].Freq += count; 72517651Speter } else if (curlen != 0) { 72617651Speter if (curlen != prevlen) s->bl_tree[curlen].Freq++; 72717651Speter s->bl_tree[REP_3_6].Freq++; 72817651Speter } else if (count <= 10) { 72917651Speter s->bl_tree[REPZ_3_10].Freq++; 73017651Speter } else { 73117651Speter s->bl_tree[REPZ_11_138].Freq++; 73217651Speter } 73317651Speter count = 0; prevlen = curlen; 73417651Speter if (nextlen == 0) { 73517651Speter max_count = 138, min_count = 3; 73617651Speter } else if (curlen == nextlen) { 73717651Speter max_count = 6, min_count = 3; 73817651Speter } else { 73917651Speter max_count = 7, min_count = 4; 74017651Speter } 74117651Speter } 74217651Speter} 74317651Speter 74417651Speter/* =========================================================================== 74517651Speter * Send a literal or distance tree in compressed form, using the codes in 74617651Speter * bl_tree. 74717651Speter */ 74817651Speterlocal void send_tree (s, tree, max_code) 74917651Speter deflate_state *s; 75017651Speter ct_data *tree; /* the tree to be scanned */ 75117651Speter int max_code; /* and its largest code of non zero frequency */ 75217651Speter{ 75317651Speter int n; /* iterates over all tree elements */ 75417651Speter int prevlen = -1; /* last emitted length */ 75517651Speter int curlen; /* length of current code */ 75617651Speter int nextlen = tree[0].Len; /* length of next code */ 75717651Speter int count = 0; /* repeat count of the current code */ 75817651Speter int max_count = 7; /* max repeat count */ 75917651Speter int min_count = 4; /* min repeat count */ 76017651Speter 76117651Speter /* tree[max_code+1].Len = -1; */ /* guard already set */ 76217651Speter if (nextlen == 0) max_count = 138, min_count = 3; 76317651Speter 76417651Speter for (n = 0; n <= max_code; n++) { 76517651Speter curlen = nextlen; nextlen = tree[n+1].Len; 76617651Speter if (++count < max_count && curlen == nextlen) { 76717651Speter continue; 76817651Speter } else if (count < min_count) { 76917651Speter do { send_code(s, curlen, s->bl_tree); } while (--count != 0); 77017651Speter 77117651Speter } else if (curlen != 0) { 77217651Speter if (curlen != prevlen) { 77317651Speter send_code(s, curlen, s->bl_tree); count--; 77417651Speter } 77517651Speter Assert(count >= 3 && count <= 6, " 3_6?"); 77617651Speter send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); 77717651Speter 77817651Speter } else if (count <= 10) { 77917651Speter send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); 78017651Speter 78117651Speter } else { 78217651Speter send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); 78317651Speter } 78417651Speter count = 0; prevlen = curlen; 78517651Speter if (nextlen == 0) { 78617651Speter max_count = 138, min_count = 3; 78717651Speter } else if (curlen == nextlen) { 78817651Speter max_count = 6, min_count = 3; 78917651Speter } else { 79017651Speter max_count = 7, min_count = 4; 79117651Speter } 79217651Speter } 79317651Speter} 79417651Speter 79517651Speter/* =========================================================================== 79617651Speter * Construct the Huffman tree for the bit lengths and return the index in 79717651Speter * bl_order of the last bit length code to send. 79817651Speter */ 79917651Speterlocal int build_bl_tree(s) 80017651Speter deflate_state *s; 80117651Speter{ 80217651Speter int max_blindex; /* index of last bit length code of non zero freq */ 80317651Speter 80417651Speter /* Determine the bit length frequencies for literal and distance trees */ 80517651Speter scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); 80617651Speter scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); 80717651Speter 80817651Speter /* Build the bit length tree: */ 80917651Speter build_tree(s, (tree_desc *)(&(s->bl_desc))); 81017651Speter /* opt_len now includes the length of the tree representations, except 81117651Speter * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. 81217651Speter */ 81317651Speter 81417651Speter /* Determine the number of bit length codes to send. The pkzip format 81517651Speter * requires that at least 4 bit length codes be sent. (appnote.txt says 81617651Speter * 3 but the actual value used is 4.) 81717651Speter */ 81817651Speter for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { 81917651Speter if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; 82017651Speter } 82117651Speter /* Update opt_len to include the bit length tree and counts */ 822313796Sdelphij s->opt_len += 3*((ulg)max_blindex+1) + 5+5+4; 82317651Speter Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", 82417651Speter s->opt_len, s->static_len)); 82517651Speter 82617651Speter return max_blindex; 82717651Speter} 82817651Speter 82917651Speter/* =========================================================================== 83017651Speter * Send the header for a block using dynamic Huffman trees: the counts, the 83117651Speter * lengths of the bit length codes, the literal tree and the distance tree. 83217651Speter * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. 83317651Speter */ 83417651Speterlocal void send_all_trees(s, lcodes, dcodes, blcodes) 83517651Speter deflate_state *s; 83617651Speter int lcodes, dcodes, blcodes; /* number of codes for each tree */ 83717651Speter{ 83817651Speter int rank; /* index in bl_order */ 83917651Speter 84017651Speter Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); 84117651Speter Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, 84217651Speter "too many codes"); 84317651Speter Tracev((stderr, "\nbl counts: ")); 84417651Speter send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ 84517651Speter send_bits(s, dcodes-1, 5); 84617651Speter send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ 84717651Speter for (rank = 0; rank < blcodes; rank++) { 84817651Speter Tracev((stderr, "\nbl code %2d ", bl_order[rank])); 84917651Speter send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); 85017651Speter } 85117651Speter Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); 85217651Speter 85317651Speter send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ 85417651Speter Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); 85517651Speter 85617651Speter send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ 85717651Speter Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); 85817651Speter} 85917651Speter 86017651Speter/* =========================================================================== 86117651Speter * Send a stored block 86217651Speter */ 863206905Sdelphijvoid ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last) 86417651Speter deflate_state *s; 86517651Speter charf *buf; /* input block */ 86617651Speter ulg stored_len; /* length of input block */ 867205194Sdelphij int last; /* one if this is the last block for a file */ 86817651Speter{ 869205194Sdelphij send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */ 870313796Sdelphij bi_windup(s); /* align on byte boundary */ 871313796Sdelphij put_short(s, (ush)stored_len); 872313796Sdelphij put_short(s, (ush)~stored_len); 873313796Sdelphij zmemcpy(s->pending_buf + s->pending, (Bytef *)buf, stored_len); 874313796Sdelphij s->pending += stored_len; 875313796Sdelphij#ifdef ZLIB_DEBUG 87617651Speter s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; 87717651Speter s->compressed_len += (stored_len + 4) << 3; 878313796Sdelphij s->bits_sent += 2*16; 879313796Sdelphij s->bits_sent += stored_len<<3; 88042468Speter#endif 88117651Speter} 88217651Speter 88317651Speter/* =========================================================================== 884230837Sdelphij * Flush the bits in the bit buffer to pending output (leaves at most 7 bits) 885230837Sdelphij */ 886230837Sdelphijvoid ZLIB_INTERNAL _tr_flush_bits(s) 887230837Sdelphij deflate_state *s; 888230837Sdelphij{ 889230837Sdelphij bi_flush(s); 890230837Sdelphij} 891230837Sdelphij 892230837Sdelphij/* =========================================================================== 89317651Speter * Send one empty static block to give enough lookahead for inflate. 89417651Speter * This takes 10 bits, of which 7 may remain in the bit buffer. 89517651Speter */ 896206905Sdelphijvoid ZLIB_INTERNAL _tr_align(s) 89717651Speter deflate_state *s; 89817651Speter{ 89917651Speter send_bits(s, STATIC_TREES<<1, 3); 90017651Speter send_code(s, END_BLOCK, static_ltree); 901313796Sdelphij#ifdef ZLIB_DEBUG 90217651Speter s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ 90342468Speter#endif 90417651Speter bi_flush(s); 90517651Speter} 90617651Speter 90717651Speter/* =========================================================================== 90817651Speter * Determine the best encoding for the current block: dynamic trees, static 909313796Sdelphij * trees or store, and write out the encoded block. 91017651Speter */ 911206905Sdelphijvoid ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) 91217651Speter deflate_state *s; 91317651Speter charf *buf; /* input block, or NULL if too old */ 91417651Speter ulg stored_len; /* length of input block */ 915205194Sdelphij int last; /* one if this is the last block for a file */ 91617651Speter{ 91717651Speter ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ 91817651Speter int max_blindex = 0; /* index of last bit length code of non zero freq */ 91917651Speter 92017651Speter /* Build the Huffman trees unless a stored block is forced */ 92117651Speter if (s->level > 0) { 92217651Speter 923157043Sdes /* Check if the file is binary or text */ 924205194Sdelphij if (s->strm->data_type == Z_UNKNOWN) 925205194Sdelphij s->strm->data_type = detect_data_type(s); 92617651Speter 927131377Stjr /* Construct the literal and distance trees */ 928131377Stjr build_tree(s, (tree_desc *)(&(s->l_desc))); 929131377Stjr Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, 930131377Stjr s->static_len)); 93117651Speter 932131377Stjr build_tree(s, (tree_desc *)(&(s->d_desc))); 933131377Stjr Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, 934131377Stjr s->static_len)); 935131377Stjr /* At this point, opt_len and static_len are the total bit lengths of 936131377Stjr * the compressed block data, excluding the tree representations. 937131377Stjr */ 93817651Speter 939131377Stjr /* Build the bit length tree for the above two trees, and get the index 940131377Stjr * in bl_order of the last bit length code to send. 941131377Stjr */ 942131377Stjr max_blindex = build_bl_tree(s); 94317651Speter 944131377Stjr /* Determine the best encoding. Compute the block lengths in bytes. */ 945131377Stjr opt_lenb = (s->opt_len+3+7)>>3; 946131377Stjr static_lenb = (s->static_len+3+7)>>3; 94717651Speter 948131377Stjr Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", 949131377Stjr opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, 950131377Stjr s->last_lit)); 95117651Speter 952131377Stjr if (static_lenb <= opt_lenb) opt_lenb = static_lenb; 95317651Speter 95417651Speter } else { 95517651Speter Assert(buf != (char*)0, "lost buf"); 956131377Stjr opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ 95717651Speter } 95817651Speter 95917651Speter#ifdef FORCE_STORED 96017651Speter if (buf != (char*)0) { /* force stored block */ 96117651Speter#else 96217651Speter if (stored_len+4 <= opt_lenb && buf != (char*)0) { 96317651Speter /* 4: two words for the lengths */ 96417651Speter#endif 96517651Speter /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. 96617651Speter * Otherwise we can't have processed more than WSIZE input bytes since 96717651Speter * the last block flush, because compression would have been 96817651Speter * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to 96917651Speter * transform a block into a stored block. 97017651Speter */ 971205194Sdelphij _tr_stored_block(s, buf, stored_len, last); 97217651Speter 97317651Speter#ifdef FORCE_STATIC 97417651Speter } else if (static_lenb >= 0) { /* force static trees */ 97517651Speter#else 976157043Sdes } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { 97717651Speter#endif 978205194Sdelphij send_bits(s, (STATIC_TREES<<1)+last, 3); 979250224Sdelphij compress_block(s, (const ct_data *)static_ltree, 980250224Sdelphij (const ct_data *)static_dtree); 981313796Sdelphij#ifdef ZLIB_DEBUG 98217651Speter s->compressed_len += 3 + s->static_len; 98342468Speter#endif 98417651Speter } else { 985205194Sdelphij send_bits(s, (DYN_TREES<<1)+last, 3); 98617651Speter send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, 98717651Speter max_blindex+1); 988250224Sdelphij compress_block(s, (const ct_data *)s->dyn_ltree, 989250224Sdelphij (const ct_data *)s->dyn_dtree); 990313796Sdelphij#ifdef ZLIB_DEBUG 99117651Speter s->compressed_len += 3 + s->opt_len; 99242468Speter#endif 99317651Speter } 99417651Speter Assert (s->compressed_len == s->bits_sent, "bad compressed size"); 99542468Speter /* The above check is made mod 2^32, for files larger than 512 MB 99642468Speter * and uLong implemented on 32 bits. 99742468Speter */ 99817651Speter init_block(s); 99917651Speter 1000205194Sdelphij if (last) { 100117651Speter bi_windup(s); 1002313796Sdelphij#ifdef ZLIB_DEBUG 100317651Speter s->compressed_len += 7; /* align on byte boundary */ 100442468Speter#endif 100517651Speter } 100617651Speter Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, 1007205194Sdelphij s->compressed_len-7*last)); 100817651Speter} 100917651Speter 101017651Speter/* =========================================================================== 101117651Speter * Save the match info and tally the frequency counts. Return true if 101217651Speter * the current block must be flushed. 101317651Speter */ 1014206905Sdelphijint ZLIB_INTERNAL _tr_tally (s, dist, lc) 101517651Speter deflate_state *s; 101617651Speter unsigned dist; /* distance of matched string */ 101717651Speter unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ 101817651Speter{ 101917651Speter s->d_buf[s->last_lit] = (ush)dist; 102017651Speter s->l_buf[s->last_lit++] = (uch)lc; 102117651Speter if (dist == 0) { 102217651Speter /* lc is the unmatched char */ 102317651Speter s->dyn_ltree[lc].Freq++; 102417651Speter } else { 102517651Speter s->matches++; 102617651Speter /* Here, lc is the match length - MIN_MATCH */ 102717651Speter dist--; /* dist = match distance - 1 */ 102817651Speter Assert((ush)dist < (ush)MAX_DIST(s) && 102917651Speter (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && 103017651Speter (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); 103117651Speter 103233904Ssteve s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; 103317651Speter s->dyn_dtree[d_code(dist)].Freq++; 103417651Speter } 103517651Speter 103633904Ssteve#ifdef TRUNCATE_BLOCK 103717651Speter /* Try to guess if it is profitable to stop the current block here */ 103833904Ssteve if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { 103917651Speter /* Compute an upper bound for the compressed length */ 104017651Speter ulg out_length = (ulg)s->last_lit*8L; 104117651Speter ulg in_length = (ulg)((long)s->strstart - s->block_start); 104217651Speter int dcode; 104317651Speter for (dcode = 0; dcode < D_CODES; dcode++) { 104417651Speter out_length += (ulg)s->dyn_dtree[dcode].Freq * 104517651Speter (5L+extra_dbits[dcode]); 104617651Speter } 104717651Speter out_length >>= 3; 104817651Speter Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", 104917651Speter s->last_lit, in_length, out_length, 105017651Speter 100L - out_length*100L/in_length)); 105117651Speter if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; 105217651Speter } 105333904Ssteve#endif 105417651Speter return (s->last_lit == s->lit_bufsize-1); 105517651Speter /* We avoid equality with lit_bufsize because of wraparound at 64K 105617651Speter * on 16 bit machines and because stored blocks are restricted to 105717651Speter * 64K-1 bytes. 105817651Speter */ 105917651Speter} 106017651Speter 106117651Speter/* =========================================================================== 106217651Speter * Send the block data compressed using the given Huffman trees 106317651Speter */ 106417651Speterlocal void compress_block(s, ltree, dtree) 106517651Speter deflate_state *s; 1066250224Sdelphij const ct_data *ltree; /* literal tree */ 1067250224Sdelphij const ct_data *dtree; /* distance tree */ 106817651Speter{ 106917651Speter unsigned dist; /* distance of matched string */ 107017651Speter int lc; /* match length or unmatched char (if dist == 0) */ 107117651Speter unsigned lx = 0; /* running index in l_buf */ 107217651Speter unsigned code; /* the code to send */ 107317651Speter int extra; /* number of extra bits to send */ 107417651Speter 107517651Speter if (s->last_lit != 0) do { 107617651Speter dist = s->d_buf[lx]; 107717651Speter lc = s->l_buf[lx++]; 107817651Speter if (dist == 0) { 107917651Speter send_code(s, lc, ltree); /* send a literal byte */ 108017651Speter Tracecv(isgraph(lc), (stderr," '%c' ", lc)); 108117651Speter } else { 108217651Speter /* Here, lc is the match length - MIN_MATCH */ 108333904Ssteve code = _length_code[lc]; 108417651Speter send_code(s, code+LITERALS+1, ltree); /* send the length code */ 108517651Speter extra = extra_lbits[code]; 108617651Speter if (extra != 0) { 108717651Speter lc -= base_length[code]; 108817651Speter send_bits(s, lc, extra); /* send the extra length bits */ 108917651Speter } 109017651Speter dist--; /* dist is now the match distance - 1 */ 109117651Speter code = d_code(dist); 109217651Speter Assert (code < D_CODES, "bad d_code"); 109317651Speter 109417651Speter send_code(s, code, dtree); /* send the distance code */ 109517651Speter extra = extra_dbits[code]; 109617651Speter if (extra != 0) { 1097313796Sdelphij dist -= (unsigned)base_dist[code]; 109817651Speter send_bits(s, dist, extra); /* send the extra distance bits */ 109917651Speter } 110017651Speter } /* literal or match pair ? */ 110117651Speter 110217651Speter /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ 1103131377Stjr Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, 1104131377Stjr "pendingBuf overflow"); 110517651Speter 110617651Speter } while (lx < s->last_lit); 110717651Speter 110817651Speter send_code(s, END_BLOCK, ltree); 110917651Speter} 111017651Speter 111117651Speter/* =========================================================================== 1112205194Sdelphij * Check if the data type is TEXT or BINARY, using the following algorithm: 1113205194Sdelphij * - TEXT if the two conditions below are satisfied: 1114205194Sdelphij * a) There are no non-portable control characters belonging to the 1115205194Sdelphij * "black list" (0..6, 14..25, 28..31). 1116205194Sdelphij * b) There is at least one printable character belonging to the 1117205194Sdelphij * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). 1118205194Sdelphij * - BINARY otherwise. 1119205194Sdelphij * - The following partially-portable control characters form a 1120205194Sdelphij * "gray list" that is ignored in this detection algorithm: 1121205194Sdelphij * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). 1122157043Sdes * IN assertion: the fields Freq of dyn_ltree are set. 112317651Speter */ 1124205194Sdelphijlocal int detect_data_type(s) 112517651Speter deflate_state *s; 112617651Speter{ 1127205194Sdelphij /* black_mask is the bit mask of black-listed bytes 1128205194Sdelphij * set bits 0..6, 14..25, and 28..31 1129205194Sdelphij * 0xf3ffc07f = binary 11110011111111111100000001111111 1130205194Sdelphij */ 1131205194Sdelphij unsigned long black_mask = 0xf3ffc07fUL; 1132157043Sdes int n; 1133157043Sdes 1134205194Sdelphij /* Check for non-textual ("black-listed") bytes. */ 1135205194Sdelphij for (n = 0; n <= 31; n++, black_mask >>= 1) 1136205194Sdelphij if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0)) 1137205194Sdelphij return Z_BINARY; 1138205194Sdelphij 1139205194Sdelphij /* Check for textual ("white-listed") bytes. */ 1140205194Sdelphij if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0 1141205194Sdelphij || s->dyn_ltree[13].Freq != 0) 1142205194Sdelphij return Z_TEXT; 1143205194Sdelphij for (n = 32; n < LITERALS; n++) 1144157043Sdes if (s->dyn_ltree[n].Freq != 0) 1145205194Sdelphij return Z_TEXT; 1146205194Sdelphij 1147205194Sdelphij /* There are no "black-listed" or "white-listed" bytes: 1148205194Sdelphij * this stream either is empty or has tolerated ("gray-listed") bytes only. 1149205194Sdelphij */ 1150205194Sdelphij return Z_BINARY; 115117651Speter} 115217651Speter 115317651Speter/* =========================================================================== 115417651Speter * Reverse the first len bits of a code, using straightforward code (a faster 115517651Speter * method would use a table) 115617651Speter * IN assertion: 1 <= len <= 15 115717651Speter */ 115817651Speterlocal unsigned bi_reverse(code, len) 115917651Speter unsigned code; /* the value to invert */ 116017651Speter int len; /* its bit length */ 116117651Speter{ 116217651Speter register unsigned res = 0; 116317651Speter do { 116417651Speter res |= code & 1; 116517651Speter code >>= 1, res <<= 1; 116617651Speter } while (--len > 0); 116717651Speter return res >> 1; 116817651Speter} 116917651Speter 117017651Speter/* =========================================================================== 117117651Speter * Flush the bit buffer, keeping at most 7 bits in it. 117217651Speter */ 117317651Speterlocal void bi_flush(s) 117417651Speter deflate_state *s; 117517651Speter{ 117617651Speter if (s->bi_valid == 16) { 117717651Speter put_short(s, s->bi_buf); 117817651Speter s->bi_buf = 0; 117917651Speter s->bi_valid = 0; 118017651Speter } else if (s->bi_valid >= 8) { 118117651Speter put_byte(s, (Byte)s->bi_buf); 118217651Speter s->bi_buf >>= 8; 118317651Speter s->bi_valid -= 8; 118417651Speter } 118517651Speter} 118617651Speter 118717651Speter/* =========================================================================== 118817651Speter * Flush the bit buffer and align the output on a byte boundary 118917651Speter */ 119017651Speterlocal void bi_windup(s) 119117651Speter deflate_state *s; 119217651Speter{ 119317651Speter if (s->bi_valid > 8) { 119417651Speter put_short(s, s->bi_buf); 119517651Speter } else if (s->bi_valid > 0) { 119617651Speter put_byte(s, (Byte)s->bi_buf); 119717651Speter } 119817651Speter s->bi_buf = 0; 119917651Speter s->bi_valid = 0; 1200313796Sdelphij#ifdef ZLIB_DEBUG 120117651Speter s->bits_sent = (s->bits_sent+7) & ~7; 120217651Speter#endif 120317651Speter} 1204