117651Speter/* trees.c -- output deflated data using Huffman coding 2237410Sdelphij * Copyright (C) 1995-2012 Jean-loup Gailly 3205471Sdelphij * detect_data_type() function provided freely by Cosmin Truta, 2006 4131380Stjr * 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 33146081Skientzle/* @(#) $Id$ */ 3417651Speter 3533908Ssteve/* #define GEN_TREES_H */ 3633908Ssteve 3717651Speter#include "deflate.h" 3817651Speter 3917651Speter#ifdef 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 6233908Sstevelocal 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 6533908Sstevelocal 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 6833908Sstevelocal 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 7133908Sstevelocal 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 8133908Ssteve#define DIST_CODE_LEN 512 /* see definition of array dist_code below */ 8233908Ssteve 8333908Ssteve#if defined(GEN_TREES_H) || !defined(STDC) 8433908Ssteve/* non ANSI compilers may not accept trees.h */ 8533908Ssteve 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 9833908Ssteveuch _dist_code[DIST_CODE_LEN]; 9933908Ssteve/* 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 10433908Ssteveuch _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 11333908Ssteve#else 11433908Ssteve# include "trees.h" 11533908Ssteve#endif /* GEN_TREES_H */ 11633908Ssteve 11717651Speterstruct static_tree_desc_s { 11833908Ssteve const ct_data *static_tree; /* static tree or NULL */ 11933908Ssteve 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 12517651Speterlocal static_tree_desc static_l_desc = 12617651Speter{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; 12717651Speter 12817651Speterlocal static_tree_desc static_d_desc = 12917651Speter{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; 13017651Speter 13117651Speterlocal static_tree_desc static_bl_desc = 13233908Ssteve{(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)); 149250261Sdelphijlocal void compress_block OF((deflate_state *s, const ct_data *ltree, 150250261Sdelphij const ct_data *dtree)); 151205471Sdelphijlocal 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)); 15517651Speterlocal void copy_block OF((deflate_state *s, charf *buf, unsigned len, 15617651Speter int header)); 15717651Speter 15833908Ssteve#ifdef GEN_TREES_H 15933908Sstevelocal void gen_trees_header OF((void)); 16033908Ssteve#endif 16133908Ssteve 16217651Speter#ifndef DEBUG 16317651Speter# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) 16417651Speter /* Send a code of the given tree. c and tree must not have side effects */ 16517651Speter 16617651Speter#else /* DEBUG */ 16717651Speter# define send_code(s, c, tree) \ 16833908Ssteve { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ 16917651Speter send_bits(s, tree[c].Code, tree[c].Len); } 17017651Speter#endif 17117651Speter 17217651Speter/* =========================================================================== 17317651Speter * Output a short LSB first on the stream. 17417651Speter * IN assertion: there is enough room in pendingBuf. 17517651Speter */ 17617651Speter#define put_short(s, w) { \ 17717651Speter put_byte(s, (uch)((w) & 0xff)); \ 17817651Speter put_byte(s, (uch)((ush)(w) >> 8)); \ 17917651Speter} 18017651Speter 18117651Speter/* =========================================================================== 18217651Speter * Send a value on a given number of bits. 18317651Speter * IN assertion: length <= 16 and value fits in length bits. 18417651Speter */ 18517651Speter#ifdef DEBUG 18617651Speterlocal void send_bits OF((deflate_state *s, int value, int length)); 18717651Speter 18817651Speterlocal void send_bits(s, value, length) 18917651Speter deflate_state *s; 19017651Speter int value; /* value to send */ 19117651Speter int length; /* number of bits */ 19217651Speter{ 19317651Speter Tracevv((stderr," l %2d v %4x ", length, value)); 19417651Speter Assert(length > 0 && length <= 15, "invalid length"); 19517651Speter s->bits_sent += (ulg)length; 19617651Speter 19717651Speter /* If not enough room in bi_buf, use (valid) bits from bi_buf and 19817651Speter * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) 19917651Speter * unused bits in value. 20017651Speter */ 20117651Speter if (s->bi_valid > (int)Buf_size - length) { 202205471Sdelphij s->bi_buf |= (ush)value << s->bi_valid; 20317651Speter put_short(s, s->bi_buf); 20417651Speter s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); 20517651Speter s->bi_valid += length - Buf_size; 20617651Speter } else { 207205471Sdelphij s->bi_buf |= (ush)value << s->bi_valid; 20817651Speter s->bi_valid += length; 20917651Speter } 21017651Speter} 21117651Speter#else /* !DEBUG */ 21217651Speter 21317651Speter#define send_bits(s, value, length) \ 21417651Speter{ int len = length;\ 21517651Speter if (s->bi_valid > (int)Buf_size - len) {\ 21617651Speter int val = value;\ 217205471Sdelphij s->bi_buf |= (ush)val << s->bi_valid;\ 21817651Speter put_short(s, s->bi_buf);\ 21917651Speter s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ 22017651Speter s->bi_valid += len - Buf_size;\ 22117651Speter } else {\ 222205471Sdelphij s->bi_buf |= (ush)(value) << s->bi_valid;\ 22317651Speter s->bi_valid += len;\ 22417651Speter }\ 22517651Speter} 22617651Speter#endif /* DEBUG */ 22717651Speter 22817651Speter 22917651Speter/* the arguments must not have side effects */ 23017651Speter 23117651Speter/* =========================================================================== 23233908Ssteve * Initialize the various 'constant' tables. 23317651Speter */ 23417651Speterlocal void tr_static_init() 23517651Speter{ 23633908Ssteve#if defined(GEN_TREES_H) || !defined(STDC) 23717651Speter static int static_init_done = 0; 23817651Speter int n; /* iterates over tree elements */ 23917651Speter int bits; /* bit counter */ 24017651Speter int length; /* length value */ 24117651Speter int code; /* code value */ 24217651Speter int dist; /* distance index */ 24317651Speter ush bl_count[MAX_BITS+1]; 24417651Speter /* number of codes at each bit length for an optimal tree */ 24517651Speter 24617651Speter if (static_init_done) return; 24717651Speter 24842471Speter /* For some embedded targets, global variables are not initialized: */ 249205471Sdelphij#ifdef NO_INIT_GLOBAL_POINTERS 25042471Speter static_l_desc.static_tree = static_ltree; 25142471Speter static_l_desc.extra_bits = extra_lbits; 25242471Speter static_d_desc.static_tree = static_dtree; 25342471Speter static_d_desc.extra_bits = extra_dbits; 25442471Speter static_bl_desc.extra_bits = extra_blbits; 255205471Sdelphij#endif 25642471Speter 25717651Speter /* Initialize the mapping length (0..255) -> length code (0..28) */ 25817651Speter length = 0; 25917651Speter for (code = 0; code < LENGTH_CODES-1; code++) { 26017651Speter base_length[code] = length; 26117651Speter for (n = 0; n < (1<<extra_lbits[code]); n++) { 26233908Ssteve _length_code[length++] = (uch)code; 26317651Speter } 26417651Speter } 26517651Speter Assert (length == 256, "tr_static_init: length != 256"); 26617651Speter /* Note that the length 255 (match length 258) can be represented 26717651Speter * in two different ways: code 284 + 5 bits or code 285, so we 26817651Speter * overwrite length_code[255] to use the best encoding: 26917651Speter */ 27033908Ssteve _length_code[length-1] = (uch)code; 27117651Speter 27217651Speter /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ 27317651Speter dist = 0; 27417651Speter for (code = 0 ; code < 16; code++) { 27517651Speter base_dist[code] = dist; 27617651Speter for (n = 0; n < (1<<extra_dbits[code]); n++) { 27733908Ssteve _dist_code[dist++] = (uch)code; 27817651Speter } 27917651Speter } 28017651Speter Assert (dist == 256, "tr_static_init: dist != 256"); 28117651Speter dist >>= 7; /* from now on, all distances are divided by 128 */ 28217651Speter for ( ; code < D_CODES; code++) { 28317651Speter base_dist[code] = dist << 7; 28417651Speter for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { 28533908Ssteve _dist_code[256 + dist++] = (uch)code; 28617651Speter } 28717651Speter } 28817651Speter Assert (dist == 256, "tr_static_init: 256+dist != 512"); 28917651Speter 29017651Speter /* Construct the codes of the static literal tree */ 29117651Speter for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; 29217651Speter n = 0; 29317651Speter while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; 29417651Speter while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; 29517651Speter while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; 29617651Speter while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; 29717651Speter /* Codes 286 and 287 do not exist, but we must include them in the 29817651Speter * tree construction to get a canonical Huffman tree (longest code 29917651Speter * all ones) 30017651Speter */ 30117651Speter gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); 30217651Speter 30317651Speter /* The static distance tree is trivial: */ 30417651Speter for (n = 0; n < D_CODES; n++) { 30517651Speter static_dtree[n].Len = 5; 30617651Speter static_dtree[n].Code = bi_reverse((unsigned)n, 5); 30717651Speter } 30817651Speter static_init_done = 1; 30933908Ssteve 31033908Ssteve# ifdef GEN_TREES_H 31133908Ssteve gen_trees_header(); 31233908Ssteve# endif 31333908Ssteve#endif /* defined(GEN_TREES_H) || !defined(STDC) */ 31417651Speter} 31517651Speter 31617651Speter/* =========================================================================== 31733908Ssteve * Genererate the file trees.h describing the static trees. 31833908Ssteve */ 31933908Ssteve#ifdef GEN_TREES_H 32033908Ssteve# ifndef DEBUG 32133908Ssteve# include <stdio.h> 32233908Ssteve# endif 32333908Ssteve 32433908Ssteve# define SEPARATOR(i, last, width) \ 32533908Ssteve ((i) == (last)? "\n};\n\n" : \ 32633908Ssteve ((i) % (width) == (width)-1 ? ",\n" : ", ")) 32733908Ssteve 32833908Sstevevoid gen_trees_header() 32933908Ssteve{ 33033908Ssteve FILE *header = fopen("trees.h", "w"); 33133908Ssteve int i; 33233908Ssteve 33333908Ssteve Assert (header != NULL, "Can't open trees.h"); 33433908Ssteve fprintf(header, 335131380Stjr "/* header created automatically with -DGEN_TREES_H */\n\n"); 33633908Ssteve 33733908Ssteve fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); 33833908Ssteve for (i = 0; i < L_CODES+2; i++) { 339131380Stjr fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, 340131380Stjr static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); 34133908Ssteve } 34233908Ssteve 34333908Ssteve fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); 34433908Ssteve for (i = 0; i < D_CODES; i++) { 345131380Stjr fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, 346131380Stjr static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); 34733908Ssteve } 34833908Ssteve 349206924Sdelphij fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n"); 35033908Ssteve for (i = 0; i < DIST_CODE_LEN; i++) { 351131380Stjr fprintf(header, "%2u%s", _dist_code[i], 352131380Stjr SEPARATOR(i, DIST_CODE_LEN-1, 20)); 35333908Ssteve } 35433908Ssteve 355206924Sdelphij fprintf(header, 356206924Sdelphij "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); 35733908Ssteve for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { 358131380Stjr fprintf(header, "%2u%s", _length_code[i], 359131380Stjr SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); 36033908Ssteve } 36133908Ssteve 36233908Ssteve fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); 36333908Ssteve for (i = 0; i < LENGTH_CODES; i++) { 364131380Stjr fprintf(header, "%1u%s", base_length[i], 365131380Stjr SEPARATOR(i, LENGTH_CODES-1, 20)); 36633908Ssteve } 36733908Ssteve 36833908Ssteve fprintf(header, "local const int base_dist[D_CODES] = {\n"); 36933908Ssteve for (i = 0; i < D_CODES; i++) { 370131380Stjr fprintf(header, "%5u%s", base_dist[i], 371131380Stjr SEPARATOR(i, D_CODES-1, 10)); 37233908Ssteve } 37333908Ssteve 37433908Ssteve fclose(header); 37533908Ssteve} 37633908Ssteve#endif /* GEN_TREES_H */ 37733908Ssteve 37833908Ssteve/* =========================================================================== 37917651Speter * Initialize the tree data structures for a new zlib stream. 38017651Speter */ 381206924Sdelphijvoid ZLIB_INTERNAL _tr_init(s) 38217651Speter deflate_state *s; 38317651Speter{ 38417651Speter tr_static_init(); 38517651Speter 38617651Speter s->l_desc.dyn_tree = s->dyn_ltree; 38717651Speter s->l_desc.stat_desc = &static_l_desc; 38817651Speter 38917651Speter s->d_desc.dyn_tree = s->dyn_dtree; 39017651Speter s->d_desc.stat_desc = &static_d_desc; 39117651Speter 39217651Speter s->bl_desc.dyn_tree = s->bl_tree; 39317651Speter s->bl_desc.stat_desc = &static_bl_desc; 39417651Speter 39517651Speter s->bi_buf = 0; 39617651Speter s->bi_valid = 0; 39717651Speter#ifdef DEBUG 39842471Speter s->compressed_len = 0L; 39917651Speter s->bits_sent = 0L; 40017651Speter#endif 40117651Speter 40217651Speter /* Initialize the first block of the first file: */ 40317651Speter init_block(s); 40417651Speter} 40517651Speter 40617651Speter/* =========================================================================== 40717651Speter * Initialize a new block. 40817651Speter */ 40917651Speterlocal void init_block(s) 41017651Speter deflate_state *s; 41117651Speter{ 41217651Speter int n; /* iterates over tree elements */ 41317651Speter 41417651Speter /* Initialize the trees. */ 41517651Speter for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; 41617651Speter for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; 41717651Speter for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; 41817651Speter 41917651Speter s->dyn_ltree[END_BLOCK].Freq = 1; 42017651Speter s->opt_len = s->static_len = 0L; 42117651Speter s->last_lit = s->matches = 0; 42217651Speter} 42317651Speter 42417651Speter#define SMALLEST 1 42517651Speter/* Index within the heap array of least frequent node in the Huffman tree */ 42617651Speter 42717651Speter 42817651Speter/* =========================================================================== 42917651Speter * Remove the smallest element from the heap and recreate the heap with 43017651Speter * one less element. Updates heap and heap_len. 43117651Speter */ 43217651Speter#define pqremove(s, tree, top) \ 43317651Speter{\ 43417651Speter top = s->heap[SMALLEST]; \ 43517651Speter s->heap[SMALLEST] = s->heap[s->heap_len--]; \ 43617651Speter pqdownheap(s, tree, SMALLEST); \ 43717651Speter} 43817651Speter 43917651Speter/* =========================================================================== 44017651Speter * Compares to subtrees, using the tree depth as tie breaker when 44117651Speter * the subtrees have equal frequency. This minimizes the worst case length. 44217651Speter */ 44317651Speter#define smaller(tree, n, m, depth) \ 44417651Speter (tree[n].Freq < tree[m].Freq || \ 44517651Speter (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) 44617651Speter 44717651Speter/* =========================================================================== 44817651Speter * Restore the heap property by moving down the tree starting at node k, 44917651Speter * exchanging a node with the smallest of its two sons if necessary, stopping 45017651Speter * when the heap property is re-established (each father smaller than its 45117651Speter * two sons). 45217651Speter */ 45317651Speterlocal void pqdownheap(s, tree, k) 45417651Speter deflate_state *s; 45517651Speter ct_data *tree; /* the tree to restore */ 45617651Speter int k; /* node to move down */ 45717651Speter{ 45817651Speter int v = s->heap[k]; 45917651Speter int j = k << 1; /* left son of k */ 46017651Speter while (j <= s->heap_len) { 46117651Speter /* Set j to the smallest of the two sons: */ 46217651Speter if (j < s->heap_len && 46317651Speter smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { 46417651Speter j++; 46517651Speter } 46617651Speter /* Exit if v is smaller than both sons */ 46717651Speter if (smaller(tree, v, s->heap[j], s->depth)) break; 46817651Speter 46917651Speter /* Exchange v with the smallest son */ 47017651Speter s->heap[k] = s->heap[j]; k = j; 47117651Speter 47217651Speter /* And continue down the tree, setting j to the left son of k */ 47317651Speter j <<= 1; 47417651Speter } 47517651Speter s->heap[k] = v; 47617651Speter} 47717651Speter 47817651Speter/* =========================================================================== 47917651Speter * Compute the optimal bit lengths for a tree and update the total bit length 48017651Speter * for the current block. 48117651Speter * IN assertion: the fields freq and dad are set, heap[heap_max] and 48217651Speter * above are the tree nodes sorted by increasing frequency. 48317651Speter * OUT assertions: the field len is set to the optimal bit length, the 48417651Speter * array bl_count contains the frequencies for each bit length. 48517651Speter * The length opt_len is updated; static_len is also updated if stree is 48617651Speter * not null. 48717651Speter */ 48817651Speterlocal void gen_bitlen(s, desc) 48917651Speter deflate_state *s; 49017651Speter tree_desc *desc; /* the tree descriptor */ 49117651Speter{ 49233908Ssteve ct_data *tree = desc->dyn_tree; 49333908Ssteve int max_code = desc->max_code; 49433908Ssteve const ct_data *stree = desc->stat_desc->static_tree; 49533908Ssteve const intf *extra = desc->stat_desc->extra_bits; 49633908Ssteve int base = desc->stat_desc->extra_base; 49733908Ssteve int max_length = desc->stat_desc->max_length; 49817651Speter int h; /* heap index */ 49917651Speter int n, m; /* iterate over the tree elements */ 50017651Speter int bits; /* bit length */ 50117651Speter int xbits; /* extra bits */ 50217651Speter ush f; /* frequency */ 50317651Speter int overflow = 0; /* number of elements with bit length too large */ 50417651Speter 50517651Speter for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; 50617651Speter 50717651Speter /* In a first pass, compute the optimal bit lengths (which may 50817651Speter * overflow in the case of the bit length tree). 50917651Speter */ 51017651Speter tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ 51117651Speter 51217651Speter for (h = s->heap_max+1; h < HEAP_SIZE; h++) { 51317651Speter n = s->heap[h]; 51417651Speter bits = tree[tree[n].Dad].Len + 1; 51517651Speter if (bits > max_length) bits = max_length, overflow++; 51617651Speter tree[n].Len = (ush)bits; 51717651Speter /* We overwrite tree[n].Dad which is no longer needed */ 51817651Speter 51917651Speter if (n > max_code) continue; /* not a leaf node */ 52017651Speter 52117651Speter s->bl_count[bits]++; 52217651Speter xbits = 0; 52317651Speter if (n >= base) xbits = extra[n-base]; 52417651Speter f = tree[n].Freq; 52517651Speter s->opt_len += (ulg)f * (bits + xbits); 52617651Speter if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); 52717651Speter } 52817651Speter if (overflow == 0) return; 52917651Speter 53017651Speter Trace((stderr,"\nbit length overflow\n")); 53117651Speter /* This happens for example on obj2 and pic of the Calgary corpus */ 53217651Speter 53317651Speter /* Find the first bit length which could increase: */ 53417651Speter do { 53517651Speter bits = max_length-1; 53617651Speter while (s->bl_count[bits] == 0) bits--; 53717651Speter s->bl_count[bits]--; /* move one leaf down the tree */ 53817651Speter s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ 53917651Speter s->bl_count[max_length]--; 54017651Speter /* The brother of the overflow item also moves one step up, 54117651Speter * but this does not affect bl_count[max_length] 54217651Speter */ 54317651Speter overflow -= 2; 54417651Speter } while (overflow > 0); 54517651Speter 54617651Speter /* Now recompute all bit lengths, scanning in increasing frequency. 54717651Speter * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all 54817651Speter * lengths instead of fixing only the wrong ones. This idea is taken 54917651Speter * from 'ar' written by Haruhiko Okumura.) 55017651Speter */ 55117651Speter for (bits = max_length; bits != 0; bits--) { 55217651Speter n = s->bl_count[bits]; 55317651Speter while (n != 0) { 55417651Speter m = s->heap[--h]; 55517651Speter if (m > max_code) continue; 556157046Sdes if ((unsigned) tree[m].Len != (unsigned) bits) { 55717651Speter Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); 55817651Speter s->opt_len += ((long)bits - (long)tree[m].Len) 55917651Speter *(long)tree[m].Freq; 56017651Speter tree[m].Len = (ush)bits; 56117651Speter } 56217651Speter n--; 56317651Speter } 56417651Speter } 56517651Speter} 56617651Speter 56717651Speter/* =========================================================================== 56817651Speter * Generate the codes for a given tree and bit counts (which need not be 56917651Speter * optimal). 57017651Speter * IN assertion: the array bl_count contains the bit length statistics for 57117651Speter * the given tree and the field len is set for all tree elements. 57217651Speter * OUT assertion: the field code is set for all tree elements of non 57317651Speter * zero code length. 57417651Speter */ 57517651Speterlocal void gen_codes (tree, max_code, bl_count) 57617651Speter ct_data *tree; /* the tree to decorate */ 57717651Speter int max_code; /* largest code with non zero frequency */ 57817651Speter ushf *bl_count; /* number of codes at each bit length */ 57917651Speter{ 58017651Speter ush next_code[MAX_BITS+1]; /* next code value for each bit length */ 58117651Speter ush code = 0; /* running code value */ 58217651Speter int bits; /* bit index */ 58317651Speter int n; /* code index */ 58417651Speter 58517651Speter /* The distribution counts are first used to generate the code values 58617651Speter * without bit reversal. 58717651Speter */ 58817651Speter for (bits = 1; bits <= MAX_BITS; bits++) { 58917651Speter next_code[bits] = code = (code + bl_count[bits-1]) << 1; 59017651Speter } 59117651Speter /* Check that the bit counts in bl_count are consistent. The last code 59217651Speter * must be all ones. 59317651Speter */ 59417651Speter Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, 59517651Speter "inconsistent bit counts"); 59617651Speter Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); 59717651Speter 59817651Speter for (n = 0; n <= max_code; n++) { 59917651Speter int len = tree[n].Len; 60017651Speter if (len == 0) continue; 60117651Speter /* Now reverse the bits */ 60217651Speter tree[n].Code = bi_reverse(next_code[len]++, len); 60317651Speter 60417651Speter Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", 60517651Speter n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); 60617651Speter } 60717651Speter} 60817651Speter 60917651Speter/* =========================================================================== 61017651Speter * Construct one Huffman tree and assigns the code bit strings and lengths. 61117651Speter * Update the total bit length for the current block. 61217651Speter * IN assertion: the field freq is set for all tree elements. 61317651Speter * OUT assertions: the fields len and code are set to the optimal bit length 61417651Speter * and corresponding code. The length opt_len is updated; static_len is 61517651Speter * also updated if stree is not null. The field max_code is set. 61617651Speter */ 61717651Speterlocal void build_tree(s, desc) 61817651Speter deflate_state *s; 61917651Speter tree_desc *desc; /* the tree descriptor */ 62017651Speter{ 62133908Ssteve ct_data *tree = desc->dyn_tree; 62233908Ssteve const ct_data *stree = desc->stat_desc->static_tree; 62333908Ssteve int elems = desc->stat_desc->elems; 62417651Speter int n, m; /* iterate over heap elements */ 62517651Speter int max_code = -1; /* largest code with non zero frequency */ 62617651Speter int node; /* new node being created */ 62717651Speter 62817651Speter /* Construct the initial heap, with least frequent element in 62917651Speter * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. 63017651Speter * heap[0] is not used. 63117651Speter */ 63217651Speter s->heap_len = 0, s->heap_max = HEAP_SIZE; 63317651Speter 63417651Speter for (n = 0; n < elems; n++) { 63517651Speter if (tree[n].Freq != 0) { 63617651Speter s->heap[++(s->heap_len)] = max_code = n; 63717651Speter s->depth[n] = 0; 63817651Speter } else { 63917651Speter tree[n].Len = 0; 64017651Speter } 64117651Speter } 64217651Speter 64317651Speter /* The pkzip format requires that at least one distance code exists, 64417651Speter * and that at least one bit should be sent even if there is only one 64517651Speter * possible code. So to avoid special checks later on we force at least 64617651Speter * two codes of non zero frequency. 64717651Speter */ 64817651Speter while (s->heap_len < 2) { 64917651Speter node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); 65017651Speter tree[node].Freq = 1; 65117651Speter s->depth[node] = 0; 65217651Speter s->opt_len--; if (stree) s->static_len -= stree[node].Len; 65317651Speter /* node is 0 or 1 so it does not have extra bits */ 65417651Speter } 65517651Speter desc->max_code = max_code; 65617651Speter 65717651Speter /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, 65817651Speter * establish sub-heaps of increasing lengths: 65917651Speter */ 66017651Speter for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); 66117651Speter 66217651Speter /* Construct the Huffman tree by repeatedly combining the least two 66317651Speter * frequent nodes. 66417651Speter */ 66517651Speter node = elems; /* next internal node of the tree */ 66617651Speter do { 66717651Speter pqremove(s, tree, n); /* n = node of least frequency */ 66817651Speter m = s->heap[SMALLEST]; /* m = node of next least frequency */ 66917651Speter 67017651Speter s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ 67117651Speter s->heap[--(s->heap_max)] = m; 67217651Speter 67317651Speter /* Create a new node father of n and m */ 67417651Speter tree[node].Freq = tree[n].Freq + tree[m].Freq; 675131380Stjr s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? 676131380Stjr s->depth[n] : s->depth[m]) + 1); 67717651Speter tree[n].Dad = tree[m].Dad = (ush)node; 67817651Speter#ifdef DUMP_BL_TREE 67917651Speter if (tree == s->bl_tree) { 68017651Speter fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", 68117651Speter node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); 68217651Speter } 68317651Speter#endif 68417651Speter /* and insert the new node in the heap */ 68517651Speter s->heap[SMALLEST] = node++; 68617651Speter pqdownheap(s, tree, SMALLEST); 68717651Speter 68817651Speter } while (s->heap_len >= 2); 68917651Speter 69017651Speter s->heap[--(s->heap_max)] = s->heap[SMALLEST]; 69117651Speter 69217651Speter /* At this point, the fields freq and dad are set. We can now 69317651Speter * generate the bit lengths. 69417651Speter */ 69517651Speter gen_bitlen(s, (tree_desc *)desc); 69617651Speter 69717651Speter /* The field len is now set, we can generate the bit codes */ 69817651Speter gen_codes ((ct_data *)tree, max_code, s->bl_count); 69917651Speter} 70017651Speter 70117651Speter/* =========================================================================== 70217651Speter * Scan a literal or distance tree to determine the frequencies of the codes 70317651Speter * in the bit length tree. 70417651Speter */ 70517651Speterlocal void scan_tree (s, tree, max_code) 70617651Speter deflate_state *s; 70717651Speter ct_data *tree; /* the tree to be scanned */ 70817651Speter int max_code; /* and its largest code of non zero frequency */ 70917651Speter{ 71017651Speter int n; /* iterates over all tree elements */ 71117651Speter int prevlen = -1; /* last emitted length */ 71217651Speter int curlen; /* length of current code */ 71317651Speter int nextlen = tree[0].Len; /* length of next code */ 71417651Speter int count = 0; /* repeat count of the current code */ 71517651Speter int max_count = 7; /* max repeat count */ 71617651Speter int min_count = 4; /* min repeat count */ 71717651Speter 71817651Speter if (nextlen == 0) max_count = 138, min_count = 3; 71917651Speter tree[max_code+1].Len = (ush)0xffff; /* guard */ 72017651Speter 72117651Speter for (n = 0; n <= max_code; n++) { 72217651Speter curlen = nextlen; nextlen = tree[n+1].Len; 72317651Speter if (++count < max_count && curlen == nextlen) { 72417651Speter continue; 72517651Speter } else if (count < min_count) { 72617651Speter s->bl_tree[curlen].Freq += count; 72717651Speter } else if (curlen != 0) { 72817651Speter if (curlen != prevlen) s->bl_tree[curlen].Freq++; 72917651Speter s->bl_tree[REP_3_6].Freq++; 73017651Speter } else if (count <= 10) { 73117651Speter s->bl_tree[REPZ_3_10].Freq++; 73217651Speter } else { 73317651Speter s->bl_tree[REPZ_11_138].Freq++; 73417651Speter } 73517651Speter count = 0; prevlen = curlen; 73617651Speter if (nextlen == 0) { 73717651Speter max_count = 138, min_count = 3; 73817651Speter } else if (curlen == nextlen) { 73917651Speter max_count = 6, min_count = 3; 74017651Speter } else { 74117651Speter max_count = 7, min_count = 4; 74217651Speter } 74317651Speter } 74417651Speter} 74517651Speter 74617651Speter/* =========================================================================== 74717651Speter * Send a literal or distance tree in compressed form, using the codes in 74817651Speter * bl_tree. 74917651Speter */ 75017651Speterlocal void send_tree (s, tree, max_code) 75117651Speter deflate_state *s; 75217651Speter ct_data *tree; /* the tree to be scanned */ 75317651Speter int max_code; /* and its largest code of non zero frequency */ 75417651Speter{ 75517651Speter int n; /* iterates over all tree elements */ 75617651Speter int prevlen = -1; /* last emitted length */ 75717651Speter int curlen; /* length of current code */ 75817651Speter int nextlen = tree[0].Len; /* length of next code */ 75917651Speter int count = 0; /* repeat count of the current code */ 76017651Speter int max_count = 7; /* max repeat count */ 76117651Speter int min_count = 4; /* min repeat count */ 76217651Speter 76317651Speter /* tree[max_code+1].Len = -1; */ /* guard already set */ 76417651Speter if (nextlen == 0) max_count = 138, min_count = 3; 76517651Speter 76617651Speter for (n = 0; n <= max_code; n++) { 76717651Speter curlen = nextlen; nextlen = tree[n+1].Len; 76817651Speter if (++count < max_count && curlen == nextlen) { 76917651Speter continue; 77017651Speter } else if (count < min_count) { 77117651Speter do { send_code(s, curlen, s->bl_tree); } while (--count != 0); 77217651Speter 77317651Speter } else if (curlen != 0) { 77417651Speter if (curlen != prevlen) { 77517651Speter send_code(s, curlen, s->bl_tree); count--; 77617651Speter } 77717651Speter Assert(count >= 3 && count <= 6, " 3_6?"); 77817651Speter send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); 77917651Speter 78017651Speter } else if (count <= 10) { 78117651Speter send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); 78217651Speter 78317651Speter } else { 78417651Speter send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); 78517651Speter } 78617651Speter count = 0; prevlen = curlen; 78717651Speter if (nextlen == 0) { 78817651Speter max_count = 138, min_count = 3; 78917651Speter } else if (curlen == nextlen) { 79017651Speter max_count = 6, min_count = 3; 79117651Speter } else { 79217651Speter max_count = 7, min_count = 4; 79317651Speter } 79417651Speter } 79517651Speter} 79617651Speter 79717651Speter/* =========================================================================== 79817651Speter * Construct the Huffman tree for the bit lengths and return the index in 79917651Speter * bl_order of the last bit length code to send. 80017651Speter */ 80117651Speterlocal int build_bl_tree(s) 80217651Speter deflate_state *s; 80317651Speter{ 80417651Speter int max_blindex; /* index of last bit length code of non zero freq */ 80517651Speter 80617651Speter /* Determine the bit length frequencies for literal and distance trees */ 80717651Speter scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); 80817651Speter scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); 80917651Speter 81017651Speter /* Build the bit length tree: */ 81117651Speter build_tree(s, (tree_desc *)(&(s->bl_desc))); 81217651Speter /* opt_len now includes the length of the tree representations, except 81317651Speter * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. 81417651Speter */ 81517651Speter 81617651Speter /* Determine the number of bit length codes to send. The pkzip format 81717651Speter * requires that at least 4 bit length codes be sent. (appnote.txt says 81817651Speter * 3 but the actual value used is 4.) 81917651Speter */ 82017651Speter for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { 82117651Speter if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; 82217651Speter } 82317651Speter /* Update opt_len to include the bit length tree and counts */ 82417651Speter s->opt_len += 3*(max_blindex+1) + 5+5+4; 82517651Speter Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", 82617651Speter s->opt_len, s->static_len)); 82717651Speter 82817651Speter return max_blindex; 82917651Speter} 83017651Speter 83117651Speter/* =========================================================================== 83217651Speter * Send the header for a block using dynamic Huffman trees: the counts, the 83317651Speter * lengths of the bit length codes, the literal tree and the distance tree. 83417651Speter * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. 83517651Speter */ 83617651Speterlocal void send_all_trees(s, lcodes, dcodes, blcodes) 83717651Speter deflate_state *s; 83817651Speter int lcodes, dcodes, blcodes; /* number of codes for each tree */ 83917651Speter{ 84017651Speter int rank; /* index in bl_order */ 84117651Speter 84217651Speter Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); 84317651Speter Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, 84417651Speter "too many codes"); 84517651Speter Tracev((stderr, "\nbl counts: ")); 84617651Speter send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ 84717651Speter send_bits(s, dcodes-1, 5); 84817651Speter send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ 84917651Speter for (rank = 0; rank < blcodes; rank++) { 85017651Speter Tracev((stderr, "\nbl code %2d ", bl_order[rank])); 85117651Speter send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); 85217651Speter } 85317651Speter Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); 85417651Speter 85517651Speter send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ 85617651Speter Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); 85717651Speter 85817651Speter send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ 85917651Speter Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); 86017651Speter} 86117651Speter 86217651Speter/* =========================================================================== 86317651Speter * Send a stored block 86417651Speter */ 865206924Sdelphijvoid ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last) 86617651Speter deflate_state *s; 86717651Speter charf *buf; /* input block */ 86817651Speter ulg stored_len; /* length of input block */ 869205471Sdelphij int last; /* one if this is the last block for a file */ 87017651Speter{ 871205471Sdelphij send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */ 87242471Speter#ifdef DEBUG 87317651Speter s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; 87417651Speter s->compressed_len += (stored_len + 4) << 3; 87542471Speter#endif 87617651Speter copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ 87717651Speter} 87817651Speter 87917651Speter/* =========================================================================== 880237410Sdelphij * Flush the bits in the bit buffer to pending output (leaves at most 7 bits) 881237410Sdelphij */ 882237410Sdelphijvoid ZLIB_INTERNAL _tr_flush_bits(s) 883237410Sdelphij deflate_state *s; 884237410Sdelphij{ 885237410Sdelphij bi_flush(s); 886237410Sdelphij} 887237410Sdelphij 888237410Sdelphij/* =========================================================================== 88917651Speter * Send one empty static block to give enough lookahead for inflate. 89017651Speter * This takes 10 bits, of which 7 may remain in the bit buffer. 89117651Speter */ 892206924Sdelphijvoid ZLIB_INTERNAL _tr_align(s) 89317651Speter deflate_state *s; 89417651Speter{ 89517651Speter send_bits(s, STATIC_TREES<<1, 3); 89617651Speter send_code(s, END_BLOCK, static_ltree); 89742471Speter#ifdef DEBUG 89817651Speter s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ 89942471Speter#endif 90017651Speter bi_flush(s); 90117651Speter} 90217651Speter 90317651Speter/* =========================================================================== 90417651Speter * Determine the best encoding for the current block: dynamic trees, static 90542471Speter * trees or store, and output the encoded block to the zip file. 90617651Speter */ 907206924Sdelphijvoid ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) 90817651Speter deflate_state *s; 90917651Speter charf *buf; /* input block, or NULL if too old */ 91017651Speter ulg stored_len; /* length of input block */ 911205471Sdelphij int last; /* one if this is the last block for a file */ 91217651Speter{ 91317651Speter ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ 91417651Speter int max_blindex = 0; /* index of last bit length code of non zero freq */ 91517651Speter 91617651Speter /* Build the Huffman trees unless a stored block is forced */ 91717651Speter if (s->level > 0) { 91817651Speter 919157046Sdes /* Check if the file is binary or text */ 920205471Sdelphij if (s->strm->data_type == Z_UNKNOWN) 921205471Sdelphij s->strm->data_type = detect_data_type(s); 92217651Speter 923131380Stjr /* Construct the literal and distance trees */ 924131380Stjr build_tree(s, (tree_desc *)(&(s->l_desc))); 925131380Stjr Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, 926131380Stjr s->static_len)); 92717651Speter 928131380Stjr build_tree(s, (tree_desc *)(&(s->d_desc))); 929131380Stjr Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, 930131380Stjr s->static_len)); 931131380Stjr /* At this point, opt_len and static_len are the total bit lengths of 932131380Stjr * the compressed block data, excluding the tree representations. 933131380Stjr */ 93417651Speter 935131380Stjr /* Build the bit length tree for the above two trees, and get the index 936131380Stjr * in bl_order of the last bit length code to send. 937131380Stjr */ 938131380Stjr max_blindex = build_bl_tree(s); 93917651Speter 940131380Stjr /* Determine the best encoding. Compute the block lengths in bytes. */ 941131380Stjr opt_lenb = (s->opt_len+3+7)>>3; 942131380Stjr static_lenb = (s->static_len+3+7)>>3; 94317651Speter 944131380Stjr Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", 945131380Stjr opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, 946131380Stjr s->last_lit)); 94717651Speter 948131380Stjr if (static_lenb <= opt_lenb) opt_lenb = static_lenb; 94917651Speter 95017651Speter } else { 95117651Speter Assert(buf != (char*)0, "lost buf"); 952131380Stjr opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ 95317651Speter } 95417651Speter 95517651Speter#ifdef FORCE_STORED 95617651Speter if (buf != (char*)0) { /* force stored block */ 95717651Speter#else 95817651Speter if (stored_len+4 <= opt_lenb && buf != (char*)0) { 95917651Speter /* 4: two words for the lengths */ 96017651Speter#endif 96117651Speter /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. 96217651Speter * Otherwise we can't have processed more than WSIZE input bytes since 96317651Speter * the last block flush, because compression would have been 96417651Speter * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to 96517651Speter * transform a block into a stored block. 96617651Speter */ 967205471Sdelphij _tr_stored_block(s, buf, stored_len, last); 96817651Speter 96917651Speter#ifdef FORCE_STATIC 97017651Speter } else if (static_lenb >= 0) { /* force static trees */ 97117651Speter#else 972157046Sdes } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { 97317651Speter#endif 974205471Sdelphij send_bits(s, (STATIC_TREES<<1)+last, 3); 975250261Sdelphij compress_block(s, (const ct_data *)static_ltree, 976250261Sdelphij (const ct_data *)static_dtree); 97742471Speter#ifdef DEBUG 97817651Speter s->compressed_len += 3 + s->static_len; 97942471Speter#endif 98017651Speter } else { 981205471Sdelphij send_bits(s, (DYN_TREES<<1)+last, 3); 98217651Speter send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, 98317651Speter max_blindex+1); 984250261Sdelphij compress_block(s, (const ct_data *)s->dyn_ltree, 985250261Sdelphij (const ct_data *)s->dyn_dtree); 98642471Speter#ifdef DEBUG 98717651Speter s->compressed_len += 3 + s->opt_len; 98842471Speter#endif 98917651Speter } 99017651Speter Assert (s->compressed_len == s->bits_sent, "bad compressed size"); 99142471Speter /* The above check is made mod 2^32, for files larger than 512 MB 99242471Speter * and uLong implemented on 32 bits. 99342471Speter */ 99417651Speter init_block(s); 99517651Speter 996205471Sdelphij if (last) { 99717651Speter bi_windup(s); 99842471Speter#ifdef DEBUG 99917651Speter s->compressed_len += 7; /* align on byte boundary */ 100042471Speter#endif 100117651Speter } 100217651Speter Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, 1003205471Sdelphij s->compressed_len-7*last)); 100417651Speter} 100517651Speter 100617651Speter/* =========================================================================== 100717651Speter * Save the match info and tally the frequency counts. Return true if 100817651Speter * the current block must be flushed. 100917651Speter */ 1010206924Sdelphijint ZLIB_INTERNAL _tr_tally (s, dist, lc) 101117651Speter deflate_state *s; 101217651Speter unsigned dist; /* distance of matched string */ 101317651Speter unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ 101417651Speter{ 101517651Speter s->d_buf[s->last_lit] = (ush)dist; 101617651Speter s->l_buf[s->last_lit++] = (uch)lc; 101717651Speter if (dist == 0) { 101817651Speter /* lc is the unmatched char */ 101917651Speter s->dyn_ltree[lc].Freq++; 102017651Speter } else { 102117651Speter s->matches++; 102217651Speter /* Here, lc is the match length - MIN_MATCH */ 102317651Speter dist--; /* dist = match distance - 1 */ 102417651Speter Assert((ush)dist < (ush)MAX_DIST(s) && 102517651Speter (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && 102617651Speter (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); 102717651Speter 102833908Ssteve s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; 102917651Speter s->dyn_dtree[d_code(dist)].Freq++; 103017651Speter } 103117651Speter 103233908Ssteve#ifdef TRUNCATE_BLOCK 103317651Speter /* Try to guess if it is profitable to stop the current block here */ 103433908Ssteve if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { 103517651Speter /* Compute an upper bound for the compressed length */ 103617651Speter ulg out_length = (ulg)s->last_lit*8L; 103717651Speter ulg in_length = (ulg)((long)s->strstart - s->block_start); 103817651Speter int dcode; 103917651Speter for (dcode = 0; dcode < D_CODES; dcode++) { 104017651Speter out_length += (ulg)s->dyn_dtree[dcode].Freq * 104117651Speter (5L+extra_dbits[dcode]); 104217651Speter } 104317651Speter out_length >>= 3; 104417651Speter Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", 104517651Speter s->last_lit, in_length, out_length, 104617651Speter 100L - out_length*100L/in_length)); 104717651Speter if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; 104817651Speter } 104933908Ssteve#endif 105017651Speter return (s->last_lit == s->lit_bufsize-1); 105117651Speter /* We avoid equality with lit_bufsize because of wraparound at 64K 105217651Speter * on 16 bit machines and because stored blocks are restricted to 105317651Speter * 64K-1 bytes. 105417651Speter */ 105517651Speter} 105617651Speter 105717651Speter/* =========================================================================== 105817651Speter * Send the block data compressed using the given Huffman trees 105917651Speter */ 106017651Speterlocal void compress_block(s, ltree, dtree) 106117651Speter deflate_state *s; 1062250261Sdelphij const ct_data *ltree; /* literal tree */ 1063250261Sdelphij const ct_data *dtree; /* distance tree */ 106417651Speter{ 106517651Speter unsigned dist; /* distance of matched string */ 106617651Speter int lc; /* match length or unmatched char (if dist == 0) */ 106717651Speter unsigned lx = 0; /* running index in l_buf */ 106817651Speter unsigned code; /* the code to send */ 106917651Speter int extra; /* number of extra bits to send */ 107017651Speter 107117651Speter if (s->last_lit != 0) do { 107217651Speter dist = s->d_buf[lx]; 107317651Speter lc = s->l_buf[lx++]; 107417651Speter if (dist == 0) { 107517651Speter send_code(s, lc, ltree); /* send a literal byte */ 107617651Speter Tracecv(isgraph(lc), (stderr," '%c' ", lc)); 107717651Speter } else { 107817651Speter /* Here, lc is the match length - MIN_MATCH */ 107933908Ssteve code = _length_code[lc]; 108017651Speter send_code(s, code+LITERALS+1, ltree); /* send the length code */ 108117651Speter extra = extra_lbits[code]; 108217651Speter if (extra != 0) { 108317651Speter lc -= base_length[code]; 108417651Speter send_bits(s, lc, extra); /* send the extra length bits */ 108517651Speter } 108617651Speter dist--; /* dist is now the match distance - 1 */ 108717651Speter code = d_code(dist); 108817651Speter Assert (code < D_CODES, "bad d_code"); 108917651Speter 109017651Speter send_code(s, code, dtree); /* send the distance code */ 109117651Speter extra = extra_dbits[code]; 109217651Speter if (extra != 0) { 109317651Speter dist -= base_dist[code]; 109417651Speter send_bits(s, dist, extra); /* send the extra distance bits */ 109517651Speter } 109617651Speter } /* literal or match pair ? */ 109717651Speter 109817651Speter /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ 1099131380Stjr Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, 1100131380Stjr "pendingBuf overflow"); 110117651Speter 110217651Speter } while (lx < s->last_lit); 110317651Speter 110417651Speter send_code(s, END_BLOCK, ltree); 110517651Speter} 110617651Speter 110717651Speter/* =========================================================================== 1108205471Sdelphij * Check if the data type is TEXT or BINARY, using the following algorithm: 1109205471Sdelphij * - TEXT if the two conditions below are satisfied: 1110205471Sdelphij * a) There are no non-portable control characters belonging to the 1111205471Sdelphij * "black list" (0..6, 14..25, 28..31). 1112205471Sdelphij * b) There is at least one printable character belonging to the 1113205471Sdelphij * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). 1114205471Sdelphij * - BINARY otherwise. 1115205471Sdelphij * - The following partially-portable control characters form a 1116205471Sdelphij * "gray list" that is ignored in this detection algorithm: 1117205471Sdelphij * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). 1118157046Sdes * IN assertion: the fields Freq of dyn_ltree are set. 111917651Speter */ 1120205471Sdelphijlocal int detect_data_type(s) 112117651Speter deflate_state *s; 112217651Speter{ 1123205471Sdelphij /* black_mask is the bit mask of black-listed bytes 1124205471Sdelphij * set bits 0..6, 14..25, and 28..31 1125205471Sdelphij * 0xf3ffc07f = binary 11110011111111111100000001111111 1126205471Sdelphij */ 1127205471Sdelphij unsigned long black_mask = 0xf3ffc07fUL; 1128157046Sdes int n; 1129157046Sdes 1130205471Sdelphij /* Check for non-textual ("black-listed") bytes. */ 1131205471Sdelphij for (n = 0; n <= 31; n++, black_mask >>= 1) 1132205471Sdelphij if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0)) 1133205471Sdelphij return Z_BINARY; 1134205471Sdelphij 1135205471Sdelphij /* Check for textual ("white-listed") bytes. */ 1136205471Sdelphij if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0 1137205471Sdelphij || s->dyn_ltree[13].Freq != 0) 1138205471Sdelphij return Z_TEXT; 1139205471Sdelphij for (n = 32; n < LITERALS; n++) 1140157046Sdes if (s->dyn_ltree[n].Freq != 0) 1141205471Sdelphij return Z_TEXT; 1142205471Sdelphij 1143205471Sdelphij /* There are no "black-listed" or "white-listed" bytes: 1144205471Sdelphij * this stream either is empty or has tolerated ("gray-listed") bytes only. 1145205471Sdelphij */ 1146205471Sdelphij return Z_BINARY; 114717651Speter} 114817651Speter 114917651Speter/* =========================================================================== 115017651Speter * Reverse the first len bits of a code, using straightforward code (a faster 115117651Speter * method would use a table) 115217651Speter * IN assertion: 1 <= len <= 15 115317651Speter */ 115417651Speterlocal unsigned bi_reverse(code, len) 115517651Speter unsigned code; /* the value to invert */ 115617651Speter int len; /* its bit length */ 115717651Speter{ 115817651Speter register unsigned res = 0; 115917651Speter do { 116017651Speter res |= code & 1; 116117651Speter code >>= 1, res <<= 1; 116217651Speter } while (--len > 0); 116317651Speter return res >> 1; 116417651Speter} 116517651Speter 116617651Speter/* =========================================================================== 116717651Speter * Flush the bit buffer, keeping at most 7 bits in it. 116817651Speter */ 116917651Speterlocal void bi_flush(s) 117017651Speter deflate_state *s; 117117651Speter{ 117217651Speter if (s->bi_valid == 16) { 117317651Speter put_short(s, s->bi_buf); 117417651Speter s->bi_buf = 0; 117517651Speter s->bi_valid = 0; 117617651Speter } else if (s->bi_valid >= 8) { 117717651Speter put_byte(s, (Byte)s->bi_buf); 117817651Speter s->bi_buf >>= 8; 117917651Speter s->bi_valid -= 8; 118017651Speter } 118117651Speter} 118217651Speter 118317651Speter/* =========================================================================== 118417651Speter * Flush the bit buffer and align the output on a byte boundary 118517651Speter */ 118617651Speterlocal void bi_windup(s) 118717651Speter deflate_state *s; 118817651Speter{ 118917651Speter if (s->bi_valid > 8) { 119017651Speter put_short(s, s->bi_buf); 119117651Speter } else if (s->bi_valid > 0) { 119217651Speter put_byte(s, (Byte)s->bi_buf); 119317651Speter } 119417651Speter s->bi_buf = 0; 119517651Speter s->bi_valid = 0; 119617651Speter#ifdef DEBUG 119717651Speter s->bits_sent = (s->bits_sent+7) & ~7; 119817651Speter#endif 119917651Speter} 120017651Speter 120117651Speter/* =========================================================================== 120217651Speter * Copy a stored block, storing first the length and its 120317651Speter * one's complement if requested. 120417651Speter */ 120517651Speterlocal void copy_block(s, buf, len, header) 120617651Speter deflate_state *s; 120717651Speter charf *buf; /* the input data */ 120817651Speter unsigned len; /* its length */ 120917651Speter int header; /* true if block header must be written */ 121017651Speter{ 121117651Speter bi_windup(s); /* align on byte boundary */ 121217651Speter 121317651Speter if (header) { 1214131380Stjr put_short(s, (ush)len); 121517651Speter put_short(s, (ush)~len); 121617651Speter#ifdef DEBUG 121717651Speter s->bits_sent += 2*16; 121817651Speter#endif 121917651Speter } 122017651Speter#ifdef DEBUG 122117651Speter s->bits_sent += (ulg)len<<3; 122217651Speter#endif 122317651Speter while (len--) { 122417651Speter put_byte(s, *buf++); 122517651Speter } 122617651Speter} 1227