1*e9a128d8SLei Wen /* trees.c -- output deflated data using Huffman coding 2*e9a128d8SLei Wen * Copyright (C) 1995-2010 Jean-loup Gailly 3*e9a128d8SLei Wen * detect_data_type() function provided freely by Cosmin Truta, 2006 4*e9a128d8SLei Wen * For conditions of distribution and use, see copyright notice in zlib.h 5*e9a128d8SLei Wen */ 6*e9a128d8SLei Wen 7*e9a128d8SLei Wen /* 8*e9a128d8SLei Wen * ALGORITHM 9*e9a128d8SLei Wen * 10*e9a128d8SLei Wen * The "deflation" process uses several Huffman trees. The more 11*e9a128d8SLei Wen * common source values are represented by shorter bit sequences. 12*e9a128d8SLei Wen * 13*e9a128d8SLei Wen * Each code tree is stored in a compressed form which is itself 14*e9a128d8SLei Wen * a Huffman encoding of the lengths of all the code strings (in 15*e9a128d8SLei Wen * ascending order by source values). The actual code strings are 16*e9a128d8SLei Wen * reconstructed from the lengths in the inflate process, as described 17*e9a128d8SLei Wen * in the deflate specification. 18*e9a128d8SLei Wen * 19*e9a128d8SLei Wen * REFERENCES 20*e9a128d8SLei Wen * 21*e9a128d8SLei Wen * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". 22*e9a128d8SLei Wen * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc 23*e9a128d8SLei Wen * 24*e9a128d8SLei Wen * Storer, James A. 25*e9a128d8SLei Wen * Data Compression: Methods and Theory, pp. 49-50. 26*e9a128d8SLei Wen * Computer Science Press, 1988. ISBN 0-7167-8156-5. 27*e9a128d8SLei Wen * 28*e9a128d8SLei Wen * Sedgewick, R. 29*e9a128d8SLei Wen * Algorithms, p290. 30*e9a128d8SLei Wen * Addison-Wesley, 1983. ISBN 0-201-06672-6. 31*e9a128d8SLei Wen */ 32*e9a128d8SLei Wen 33*e9a128d8SLei Wen /* @(#) $Id$ */ 34*e9a128d8SLei Wen 35*e9a128d8SLei Wen /* #define GEN_TREES_H */ 36*e9a128d8SLei Wen 37*e9a128d8SLei Wen #include "deflate.h" 38*e9a128d8SLei Wen 39*e9a128d8SLei Wen #ifdef DEBUG 40*e9a128d8SLei Wen # include <ctype.h> 41*e9a128d8SLei Wen #endif 42*e9a128d8SLei Wen 43*e9a128d8SLei Wen /* =========================================================================== 44*e9a128d8SLei Wen * Constants 45*e9a128d8SLei Wen */ 46*e9a128d8SLei Wen 47*e9a128d8SLei Wen #define MAX_BL_BITS 7 48*e9a128d8SLei Wen /* Bit length codes must not exceed MAX_BL_BITS bits */ 49*e9a128d8SLei Wen 50*e9a128d8SLei Wen #define END_BLOCK 256 51*e9a128d8SLei Wen /* end of block literal code */ 52*e9a128d8SLei Wen 53*e9a128d8SLei Wen #define REP_3_6 16 54*e9a128d8SLei Wen /* repeat previous bit length 3-6 times (2 bits of repeat count) */ 55*e9a128d8SLei Wen 56*e9a128d8SLei Wen #define REPZ_3_10 17 57*e9a128d8SLei Wen /* repeat a zero length 3-10 times (3 bits of repeat count) */ 58*e9a128d8SLei Wen 59*e9a128d8SLei Wen #define REPZ_11_138 18 60*e9a128d8SLei Wen /* repeat a zero length 11-138 times (7 bits of repeat count) */ 61*e9a128d8SLei Wen 62*e9a128d8SLei Wen local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ 63*e9a128d8SLei Wen = {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}; 64*e9a128d8SLei Wen 65*e9a128d8SLei Wen local const int extra_dbits[D_CODES] /* extra bits for each distance code */ 66*e9a128d8SLei Wen = {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}; 67*e9a128d8SLei Wen 68*e9a128d8SLei Wen local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ 69*e9a128d8SLei Wen = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; 70*e9a128d8SLei Wen 71*e9a128d8SLei Wen local const uch bl_order[BL_CODES] 72*e9a128d8SLei Wen = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; 73*e9a128d8SLei Wen /* The lengths of the bit length codes are sent in order of decreasing 74*e9a128d8SLei Wen * probability, to avoid transmitting the lengths for unused bit length codes. 75*e9a128d8SLei Wen */ 76*e9a128d8SLei Wen 77*e9a128d8SLei Wen #define Buf_size (8 * 2*sizeof(char)) 78*e9a128d8SLei Wen /* Number of bits used within bi_buf. (bi_buf might be implemented on 79*e9a128d8SLei Wen * more than 16 bits on some systems.) 80*e9a128d8SLei Wen */ 81*e9a128d8SLei Wen 82*e9a128d8SLei Wen /* =========================================================================== 83*e9a128d8SLei Wen * Local data. These are initialized only once. 84*e9a128d8SLei Wen */ 85*e9a128d8SLei Wen 86*e9a128d8SLei Wen #define DIST_CODE_LEN 512 /* see definition of array dist_code below */ 87*e9a128d8SLei Wen 88*e9a128d8SLei Wen #if defined(GEN_TREES_H) || !defined(STDC) 89*e9a128d8SLei Wen /* non ANSI compilers may not accept trees.h */ 90*e9a128d8SLei Wen 91*e9a128d8SLei Wen local ct_data static_ltree[L_CODES+2]; 92*e9a128d8SLei Wen /* The static literal tree. Since the bit lengths are imposed, there is no 93*e9a128d8SLei Wen * need for the L_CODES extra codes used during heap construction. However 94*e9a128d8SLei Wen * The codes 286 and 287 are needed to build a canonical tree (see _tr_init 95*e9a128d8SLei Wen * below). 96*e9a128d8SLei Wen */ 97*e9a128d8SLei Wen 98*e9a128d8SLei Wen local ct_data static_dtree[D_CODES]; 99*e9a128d8SLei Wen /* The static distance tree. (Actually a trivial tree since all codes use 100*e9a128d8SLei Wen * 5 bits.) 101*e9a128d8SLei Wen */ 102*e9a128d8SLei Wen 103*e9a128d8SLei Wen uch _dist_code[DIST_CODE_LEN]; 104*e9a128d8SLei Wen /* Distance codes. The first 256 values correspond to the distances 105*e9a128d8SLei Wen * 3 .. 258, the last 256 values correspond to the top 8 bits of 106*e9a128d8SLei Wen * the 15 bit distances. 107*e9a128d8SLei Wen */ 108*e9a128d8SLei Wen 109*e9a128d8SLei Wen uch _length_code[MAX_MATCH-MIN_MATCH+1]; 110*e9a128d8SLei Wen /* length code for each normalized match length (0 == MIN_MATCH) */ 111*e9a128d8SLei Wen 112*e9a128d8SLei Wen local int base_length[LENGTH_CODES]; 113*e9a128d8SLei Wen /* First normalized length for each code (0 = MIN_MATCH) */ 114*e9a128d8SLei Wen 115*e9a128d8SLei Wen local int base_dist[D_CODES]; 116*e9a128d8SLei Wen /* First normalized distance for each code (0 = distance of 1) */ 117*e9a128d8SLei Wen 118*e9a128d8SLei Wen #else 119*e9a128d8SLei Wen # include "trees.h" 120*e9a128d8SLei Wen #endif /* GEN_TREES_H */ 121*e9a128d8SLei Wen 122*e9a128d8SLei Wen struct static_tree_desc_s { 123*e9a128d8SLei Wen const ct_data *static_tree; /* static tree or NULL */ 124*e9a128d8SLei Wen const intf *extra_bits; /* extra bits for each code or NULL */ 125*e9a128d8SLei Wen int extra_base; /* base index for extra_bits */ 126*e9a128d8SLei Wen int elems; /* max number of elements in the tree */ 127*e9a128d8SLei Wen int max_length; /* max bit length for the codes */ 128*e9a128d8SLei Wen }; 129*e9a128d8SLei Wen 130*e9a128d8SLei Wen local static_tree_desc static_l_desc = 131*e9a128d8SLei Wen {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; 132*e9a128d8SLei Wen 133*e9a128d8SLei Wen local static_tree_desc static_d_desc = 134*e9a128d8SLei Wen {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; 135*e9a128d8SLei Wen 136*e9a128d8SLei Wen local static_tree_desc static_bl_desc = 137*e9a128d8SLei Wen {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; 138*e9a128d8SLei Wen 139*e9a128d8SLei Wen /* =========================================================================== 140*e9a128d8SLei Wen * Local (static) routines in this file. 141*e9a128d8SLei Wen */ 142*e9a128d8SLei Wen 143*e9a128d8SLei Wen local void tr_static_init OF((void)); 144*e9a128d8SLei Wen local void init_block OF((deflate_state *s)); 145*e9a128d8SLei Wen local void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); 146*e9a128d8SLei Wen local void gen_bitlen OF((deflate_state *s, tree_desc *desc)); 147*e9a128d8SLei Wen local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); 148*e9a128d8SLei Wen local void build_tree OF((deflate_state *s, tree_desc *desc)); 149*e9a128d8SLei Wen local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); 150*e9a128d8SLei Wen local void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); 151*e9a128d8SLei Wen local int build_bl_tree OF((deflate_state *s)); 152*e9a128d8SLei Wen local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, 153*e9a128d8SLei Wen int blcodes)); 154*e9a128d8SLei Wen local void compress_block OF((deflate_state *s, ct_data *ltree, 155*e9a128d8SLei Wen ct_data *dtree)); 156*e9a128d8SLei Wen local int detect_data_type OF((deflate_state *s)); 157*e9a128d8SLei Wen local unsigned bi_reverse OF((unsigned value, int length)); 158*e9a128d8SLei Wen local void bi_windup OF((deflate_state *s)); 159*e9a128d8SLei Wen local void bi_flush OF((deflate_state *s)); 160*e9a128d8SLei Wen local void copy_block OF((deflate_state *s, charf *buf, unsigned len, 161*e9a128d8SLei Wen int header)); 162*e9a128d8SLei Wen 163*e9a128d8SLei Wen #ifdef GEN_TREES_H 164*e9a128d8SLei Wen local void gen_trees_header OF((void)); 165*e9a128d8SLei Wen #endif 166*e9a128d8SLei Wen 167*e9a128d8SLei Wen #ifndef DEBUG 168*e9a128d8SLei Wen # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) 169*e9a128d8SLei Wen /* Send a code of the given tree. c and tree must not have side effects */ 170*e9a128d8SLei Wen 171*e9a128d8SLei Wen #else /* DEBUG */ 172*e9a128d8SLei Wen # define send_code(s, c, tree) \ 173*e9a128d8SLei Wen { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ 174*e9a128d8SLei Wen send_bits(s, tree[c].Code, tree[c].Len); } 175*e9a128d8SLei Wen #endif 176*e9a128d8SLei Wen 177*e9a128d8SLei Wen /* =========================================================================== 178*e9a128d8SLei Wen * Output a short LSB first on the stream. 179*e9a128d8SLei Wen * IN assertion: there is enough room in pendingBuf. 180*e9a128d8SLei Wen */ 181*e9a128d8SLei Wen #define put_short(s, w) { \ 182*e9a128d8SLei Wen put_byte(s, (uch)((w) & 0xff)); \ 183*e9a128d8SLei Wen put_byte(s, (uch)((ush)(w) >> 8)); \ 184*e9a128d8SLei Wen } 185*e9a128d8SLei Wen 186*e9a128d8SLei Wen /* =========================================================================== 187*e9a128d8SLei Wen * Send a value on a given number of bits. 188*e9a128d8SLei Wen * IN assertion: length <= 16 and value fits in length bits. 189*e9a128d8SLei Wen */ 190*e9a128d8SLei Wen #ifdef DEBUG 191*e9a128d8SLei Wen local void send_bits OF((deflate_state *s, int value, int length)); 192*e9a128d8SLei Wen 193*e9a128d8SLei Wen local void send_bits(s, value, length) 194*e9a128d8SLei Wen deflate_state *s; 195*e9a128d8SLei Wen int value; /* value to send */ 196*e9a128d8SLei Wen int length; /* number of bits */ 197*e9a128d8SLei Wen { 198*e9a128d8SLei Wen Tracevv((stderr," l %2d v %4x ", length, value)); 199*e9a128d8SLei Wen Assert(length > 0 && length <= 15, "invalid length"); 200*e9a128d8SLei Wen s->bits_sent += (ulg)length; 201*e9a128d8SLei Wen 202*e9a128d8SLei Wen /* If not enough room in bi_buf, use (valid) bits from bi_buf and 203*e9a128d8SLei Wen * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) 204*e9a128d8SLei Wen * unused bits in value. 205*e9a128d8SLei Wen */ 206*e9a128d8SLei Wen if (s->bi_valid > (int)Buf_size - length) { 207*e9a128d8SLei Wen s->bi_buf |= (ush)value << s->bi_valid; 208*e9a128d8SLei Wen put_short(s, s->bi_buf); 209*e9a128d8SLei Wen s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); 210*e9a128d8SLei Wen s->bi_valid += length - Buf_size; 211*e9a128d8SLei Wen } else { 212*e9a128d8SLei Wen s->bi_buf |= (ush)value << s->bi_valid; 213*e9a128d8SLei Wen s->bi_valid += length; 214*e9a128d8SLei Wen } 215*e9a128d8SLei Wen } 216*e9a128d8SLei Wen #else /* !DEBUG */ 217*e9a128d8SLei Wen 218*e9a128d8SLei Wen #define send_bits(s, value, length) \ 219*e9a128d8SLei Wen { int len = length;\ 220*e9a128d8SLei Wen if (s->bi_valid > (int)Buf_size - len) {\ 221*e9a128d8SLei Wen int val = value;\ 222*e9a128d8SLei Wen s->bi_buf |= (ush)val << s->bi_valid;\ 223*e9a128d8SLei Wen put_short(s, s->bi_buf);\ 224*e9a128d8SLei Wen s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ 225*e9a128d8SLei Wen s->bi_valid += len - Buf_size;\ 226*e9a128d8SLei Wen } else {\ 227*e9a128d8SLei Wen s->bi_buf |= (ush)(value) << s->bi_valid;\ 228*e9a128d8SLei Wen s->bi_valid += len;\ 229*e9a128d8SLei Wen }\ 230*e9a128d8SLei Wen } 231*e9a128d8SLei Wen #endif /* DEBUG */ 232*e9a128d8SLei Wen 233*e9a128d8SLei Wen 234*e9a128d8SLei Wen /* the arguments must not have side effects */ 235*e9a128d8SLei Wen 236*e9a128d8SLei Wen /* =========================================================================== 237*e9a128d8SLei Wen * Initialize the various 'constant' tables. 238*e9a128d8SLei Wen */ 239*e9a128d8SLei Wen local void tr_static_init() 240*e9a128d8SLei Wen { 241*e9a128d8SLei Wen #if defined(GEN_TREES_H) || !defined(STDC) 242*e9a128d8SLei Wen static int static_init_done = 0; 243*e9a128d8SLei Wen int n; /* iterates over tree elements */ 244*e9a128d8SLei Wen int bits; /* bit counter */ 245*e9a128d8SLei Wen int length; /* length value */ 246*e9a128d8SLei Wen int code; /* code value */ 247*e9a128d8SLei Wen int dist; /* distance index */ 248*e9a128d8SLei Wen ush bl_count[MAX_BITS+1]; 249*e9a128d8SLei Wen /* number of codes at each bit length for an optimal tree */ 250*e9a128d8SLei Wen 251*e9a128d8SLei Wen if (static_init_done) return; 252*e9a128d8SLei Wen 253*e9a128d8SLei Wen /* For some embedded targets, global variables are not initialized: */ 254*e9a128d8SLei Wen #ifdef NO_INIT_GLOBAL_POINTERS 255*e9a128d8SLei Wen static_l_desc.static_tree = static_ltree; 256*e9a128d8SLei Wen static_l_desc.extra_bits = extra_lbits; 257*e9a128d8SLei Wen static_d_desc.static_tree = static_dtree; 258*e9a128d8SLei Wen static_d_desc.extra_bits = extra_dbits; 259*e9a128d8SLei Wen static_bl_desc.extra_bits = extra_blbits; 260*e9a128d8SLei Wen #endif 261*e9a128d8SLei Wen 262*e9a128d8SLei Wen /* Initialize the mapping length (0..255) -> length code (0..28) */ 263*e9a128d8SLei Wen length = 0; 264*e9a128d8SLei Wen for (code = 0; code < LENGTH_CODES-1; code++) { 265*e9a128d8SLei Wen base_length[code] = length; 266*e9a128d8SLei Wen for (n = 0; n < (1<<extra_lbits[code]); n++) { 267*e9a128d8SLei Wen _length_code[length++] = (uch)code; 268*e9a128d8SLei Wen } 269*e9a128d8SLei Wen } 270*e9a128d8SLei Wen Assert (length == 256, "tr_static_init: length != 256"); 271*e9a128d8SLei Wen /* Note that the length 255 (match length 258) can be represented 272*e9a128d8SLei Wen * in two different ways: code 284 + 5 bits or code 285, so we 273*e9a128d8SLei Wen * overwrite length_code[255] to use the best encoding: 274*e9a128d8SLei Wen */ 275*e9a128d8SLei Wen _length_code[length-1] = (uch)code; 276*e9a128d8SLei Wen 277*e9a128d8SLei Wen /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ 278*e9a128d8SLei Wen dist = 0; 279*e9a128d8SLei Wen for (code = 0 ; code < 16; code++) { 280*e9a128d8SLei Wen base_dist[code] = dist; 281*e9a128d8SLei Wen for (n = 0; n < (1<<extra_dbits[code]); n++) { 282*e9a128d8SLei Wen _dist_code[dist++] = (uch)code; 283*e9a128d8SLei Wen } 284*e9a128d8SLei Wen } 285*e9a128d8SLei Wen Assert (dist == 256, "tr_static_init: dist != 256"); 286*e9a128d8SLei Wen dist >>= 7; /* from now on, all distances are divided by 128 */ 287*e9a128d8SLei Wen for ( ; code < D_CODES; code++) { 288*e9a128d8SLei Wen base_dist[code] = dist << 7; 289*e9a128d8SLei Wen for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { 290*e9a128d8SLei Wen _dist_code[256 + dist++] = (uch)code; 291*e9a128d8SLei Wen } 292*e9a128d8SLei Wen } 293*e9a128d8SLei Wen Assert (dist == 256, "tr_static_init: 256+dist != 512"); 294*e9a128d8SLei Wen 295*e9a128d8SLei Wen /* Construct the codes of the static literal tree */ 296*e9a128d8SLei Wen for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; 297*e9a128d8SLei Wen n = 0; 298*e9a128d8SLei Wen while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; 299*e9a128d8SLei Wen while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; 300*e9a128d8SLei Wen while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; 301*e9a128d8SLei Wen while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; 302*e9a128d8SLei Wen /* Codes 286 and 287 do not exist, but we must include them in the 303*e9a128d8SLei Wen * tree construction to get a canonical Huffman tree (longest code 304*e9a128d8SLei Wen * all ones) 305*e9a128d8SLei Wen */ 306*e9a128d8SLei Wen gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); 307*e9a128d8SLei Wen 308*e9a128d8SLei Wen /* The static distance tree is trivial: */ 309*e9a128d8SLei Wen for (n = 0; n < D_CODES; n++) { 310*e9a128d8SLei Wen static_dtree[n].Len = 5; 311*e9a128d8SLei Wen static_dtree[n].Code = bi_reverse((unsigned)n, 5); 312*e9a128d8SLei Wen } 313*e9a128d8SLei Wen static_init_done = 1; 314*e9a128d8SLei Wen 315*e9a128d8SLei Wen # ifdef GEN_TREES_H 316*e9a128d8SLei Wen gen_trees_header(); 317*e9a128d8SLei Wen # endif 318*e9a128d8SLei Wen #endif /* defined(GEN_TREES_H) || !defined(STDC) */ 319*e9a128d8SLei Wen } 320*e9a128d8SLei Wen 321*e9a128d8SLei Wen /* =========================================================================== 322*e9a128d8SLei Wen * Genererate the file trees.h describing the static trees. 323*e9a128d8SLei Wen */ 324*e9a128d8SLei Wen #ifdef GEN_TREES_H 325*e9a128d8SLei Wen # ifndef DEBUG 326*e9a128d8SLei Wen # include <stdio.h> 327*e9a128d8SLei Wen # endif 328*e9a128d8SLei Wen 329*e9a128d8SLei Wen # define SEPARATOR(i, last, width) \ 330*e9a128d8SLei Wen ((i) == (last)? "\n};\n\n" : \ 331*e9a128d8SLei Wen ((i) % (width) == (width)-1 ? ",\n" : ", ")) 332*e9a128d8SLei Wen 333*e9a128d8SLei Wen void gen_trees_header() 334*e9a128d8SLei Wen { 335*e9a128d8SLei Wen FILE *header = fopen("trees.h", "w"); 336*e9a128d8SLei Wen int i; 337*e9a128d8SLei Wen 338*e9a128d8SLei Wen Assert (header != NULL, "Can't open trees.h"); 339*e9a128d8SLei Wen fprintf(header, 340*e9a128d8SLei Wen "/* header created automatically with -DGEN_TREES_H */\n\n"); 341*e9a128d8SLei Wen 342*e9a128d8SLei Wen fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); 343*e9a128d8SLei Wen for (i = 0; i < L_CODES+2; i++) { 344*e9a128d8SLei Wen fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, 345*e9a128d8SLei Wen static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); 346*e9a128d8SLei Wen } 347*e9a128d8SLei Wen 348*e9a128d8SLei Wen fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); 349*e9a128d8SLei Wen for (i = 0; i < D_CODES; i++) { 350*e9a128d8SLei Wen fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, 351*e9a128d8SLei Wen static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); 352*e9a128d8SLei Wen } 353*e9a128d8SLei Wen 354*e9a128d8SLei Wen fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n"); 355*e9a128d8SLei Wen for (i = 0; i < DIST_CODE_LEN; i++) { 356*e9a128d8SLei Wen fprintf(header, "%2u%s", _dist_code[i], 357*e9a128d8SLei Wen SEPARATOR(i, DIST_CODE_LEN-1, 20)); 358*e9a128d8SLei Wen } 359*e9a128d8SLei Wen 360*e9a128d8SLei Wen fprintf(header, 361*e9a128d8SLei Wen "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); 362*e9a128d8SLei Wen for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { 363*e9a128d8SLei Wen fprintf(header, "%2u%s", _length_code[i], 364*e9a128d8SLei Wen SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); 365*e9a128d8SLei Wen } 366*e9a128d8SLei Wen 367*e9a128d8SLei Wen fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); 368*e9a128d8SLei Wen for (i = 0; i < LENGTH_CODES; i++) { 369*e9a128d8SLei Wen fprintf(header, "%1u%s", base_length[i], 370*e9a128d8SLei Wen SEPARATOR(i, LENGTH_CODES-1, 20)); 371*e9a128d8SLei Wen } 372*e9a128d8SLei Wen 373*e9a128d8SLei Wen fprintf(header, "local const int base_dist[D_CODES] = {\n"); 374*e9a128d8SLei Wen for (i = 0; i < D_CODES; i++) { 375*e9a128d8SLei Wen fprintf(header, "%5u%s", base_dist[i], 376*e9a128d8SLei Wen SEPARATOR(i, D_CODES-1, 10)); 377*e9a128d8SLei Wen } 378*e9a128d8SLei Wen 379*e9a128d8SLei Wen fclose(header); 380*e9a128d8SLei Wen } 381*e9a128d8SLei Wen #endif /* GEN_TREES_H */ 382*e9a128d8SLei Wen 383*e9a128d8SLei Wen /* =========================================================================== 384*e9a128d8SLei Wen * Initialize the tree data structures for a new zlib stream. 385*e9a128d8SLei Wen */ 386*e9a128d8SLei Wen void ZLIB_INTERNAL _tr_init(s) 387*e9a128d8SLei Wen deflate_state *s; 388*e9a128d8SLei Wen { 389*e9a128d8SLei Wen tr_static_init(); 390*e9a128d8SLei Wen 391*e9a128d8SLei Wen s->l_desc.dyn_tree = s->dyn_ltree; 392*e9a128d8SLei Wen s->l_desc.stat_desc = &static_l_desc; 393*e9a128d8SLei Wen 394*e9a128d8SLei Wen s->d_desc.dyn_tree = s->dyn_dtree; 395*e9a128d8SLei Wen s->d_desc.stat_desc = &static_d_desc; 396*e9a128d8SLei Wen 397*e9a128d8SLei Wen s->bl_desc.dyn_tree = s->bl_tree; 398*e9a128d8SLei Wen s->bl_desc.stat_desc = &static_bl_desc; 399*e9a128d8SLei Wen 400*e9a128d8SLei Wen s->bi_buf = 0; 401*e9a128d8SLei Wen s->bi_valid = 0; 402*e9a128d8SLei Wen s->last_eob_len = 8; /* enough lookahead for inflate */ 403*e9a128d8SLei Wen #ifdef DEBUG 404*e9a128d8SLei Wen s->compressed_len = 0L; 405*e9a128d8SLei Wen s->bits_sent = 0L; 406*e9a128d8SLei Wen #endif 407*e9a128d8SLei Wen 408*e9a128d8SLei Wen /* Initialize the first block of the first file: */ 409*e9a128d8SLei Wen init_block(s); 410*e9a128d8SLei Wen } 411*e9a128d8SLei Wen 412*e9a128d8SLei Wen /* =========================================================================== 413*e9a128d8SLei Wen * Initialize a new block. 414*e9a128d8SLei Wen */ 415*e9a128d8SLei Wen local void init_block(s) 416*e9a128d8SLei Wen deflate_state *s; 417*e9a128d8SLei Wen { 418*e9a128d8SLei Wen int n; /* iterates over tree elements */ 419*e9a128d8SLei Wen 420*e9a128d8SLei Wen /* Initialize the trees. */ 421*e9a128d8SLei Wen for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; 422*e9a128d8SLei Wen for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; 423*e9a128d8SLei Wen for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; 424*e9a128d8SLei Wen 425*e9a128d8SLei Wen s->dyn_ltree[END_BLOCK].Freq = 1; 426*e9a128d8SLei Wen s->opt_len = s->static_len = 0L; 427*e9a128d8SLei Wen s->last_lit = s->matches = 0; 428*e9a128d8SLei Wen } 429*e9a128d8SLei Wen 430*e9a128d8SLei Wen #define SMALLEST 1 431*e9a128d8SLei Wen /* Index within the heap array of least frequent node in the Huffman tree */ 432*e9a128d8SLei Wen 433*e9a128d8SLei Wen 434*e9a128d8SLei Wen /* =========================================================================== 435*e9a128d8SLei Wen * Remove the smallest element from the heap and recreate the heap with 436*e9a128d8SLei Wen * one less element. Updates heap and heap_len. 437*e9a128d8SLei Wen */ 438*e9a128d8SLei Wen #define pqremove(s, tree, top) \ 439*e9a128d8SLei Wen {\ 440*e9a128d8SLei Wen top = s->heap[SMALLEST]; \ 441*e9a128d8SLei Wen s->heap[SMALLEST] = s->heap[s->heap_len--]; \ 442*e9a128d8SLei Wen pqdownheap(s, tree, SMALLEST); \ 443*e9a128d8SLei Wen } 444*e9a128d8SLei Wen 445*e9a128d8SLei Wen /* =========================================================================== 446*e9a128d8SLei Wen * Compares to subtrees, using the tree depth as tie breaker when 447*e9a128d8SLei Wen * the subtrees have equal frequency. This minimizes the worst case length. 448*e9a128d8SLei Wen */ 449*e9a128d8SLei Wen #define smaller(tree, n, m, depth) \ 450*e9a128d8SLei Wen (tree[n].Freq < tree[m].Freq || \ 451*e9a128d8SLei Wen (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) 452*e9a128d8SLei Wen 453*e9a128d8SLei Wen /* =========================================================================== 454*e9a128d8SLei Wen * Restore the heap property by moving down the tree starting at node k, 455*e9a128d8SLei Wen * exchanging a node with the smallest of its two sons if necessary, stopping 456*e9a128d8SLei Wen * when the heap property is re-established (each father smaller than its 457*e9a128d8SLei Wen * two sons). 458*e9a128d8SLei Wen */ 459*e9a128d8SLei Wen local void pqdownheap(s, tree, k) 460*e9a128d8SLei Wen deflate_state *s; 461*e9a128d8SLei Wen ct_data *tree; /* the tree to restore */ 462*e9a128d8SLei Wen int k; /* node to move down */ 463*e9a128d8SLei Wen { 464*e9a128d8SLei Wen int v = s->heap[k]; 465*e9a128d8SLei Wen int j = k << 1; /* left son of k */ 466*e9a128d8SLei Wen while (j <= s->heap_len) { 467*e9a128d8SLei Wen /* Set j to the smallest of the two sons: */ 468*e9a128d8SLei Wen if (j < s->heap_len && 469*e9a128d8SLei Wen smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { 470*e9a128d8SLei Wen j++; 471*e9a128d8SLei Wen } 472*e9a128d8SLei Wen /* Exit if v is smaller than both sons */ 473*e9a128d8SLei Wen if (smaller(tree, v, s->heap[j], s->depth)) break; 474*e9a128d8SLei Wen 475*e9a128d8SLei Wen /* Exchange v with the smallest son */ 476*e9a128d8SLei Wen s->heap[k] = s->heap[j]; k = j; 477*e9a128d8SLei Wen 478*e9a128d8SLei Wen /* And continue down the tree, setting j to the left son of k */ 479*e9a128d8SLei Wen j <<= 1; 480*e9a128d8SLei Wen } 481*e9a128d8SLei Wen s->heap[k] = v; 482*e9a128d8SLei Wen } 483*e9a128d8SLei Wen 484*e9a128d8SLei Wen /* =========================================================================== 485*e9a128d8SLei Wen * Compute the optimal bit lengths for a tree and update the total bit length 486*e9a128d8SLei Wen * for the current block. 487*e9a128d8SLei Wen * IN assertion: the fields freq and dad are set, heap[heap_max] and 488*e9a128d8SLei Wen * above are the tree nodes sorted by increasing frequency. 489*e9a128d8SLei Wen * OUT assertions: the field len is set to the optimal bit length, the 490*e9a128d8SLei Wen * array bl_count contains the frequencies for each bit length. 491*e9a128d8SLei Wen * The length opt_len is updated; static_len is also updated if stree is 492*e9a128d8SLei Wen * not null. 493*e9a128d8SLei Wen */ 494*e9a128d8SLei Wen local void gen_bitlen(s, desc) 495*e9a128d8SLei Wen deflate_state *s; 496*e9a128d8SLei Wen tree_desc *desc; /* the tree descriptor */ 497*e9a128d8SLei Wen { 498*e9a128d8SLei Wen ct_data *tree = desc->dyn_tree; 499*e9a128d8SLei Wen int max_code = desc->max_code; 500*e9a128d8SLei Wen const ct_data *stree = desc->stat_desc->static_tree; 501*e9a128d8SLei Wen const intf *extra = desc->stat_desc->extra_bits; 502*e9a128d8SLei Wen int base = desc->stat_desc->extra_base; 503*e9a128d8SLei Wen int max_length = desc->stat_desc->max_length; 504*e9a128d8SLei Wen int h; /* heap index */ 505*e9a128d8SLei Wen int n, m; /* iterate over the tree elements */ 506*e9a128d8SLei Wen int bits; /* bit length */ 507*e9a128d8SLei Wen int xbits; /* extra bits */ 508*e9a128d8SLei Wen ush f; /* frequency */ 509*e9a128d8SLei Wen int overflow = 0; /* number of elements with bit length too large */ 510*e9a128d8SLei Wen 511*e9a128d8SLei Wen for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; 512*e9a128d8SLei Wen 513*e9a128d8SLei Wen /* In a first pass, compute the optimal bit lengths (which may 514*e9a128d8SLei Wen * overflow in the case of the bit length tree). 515*e9a128d8SLei Wen */ 516*e9a128d8SLei Wen tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ 517*e9a128d8SLei Wen 518*e9a128d8SLei Wen for (h = s->heap_max+1; h < HEAP_SIZE; h++) { 519*e9a128d8SLei Wen n = s->heap[h]; 520*e9a128d8SLei Wen bits = tree[tree[n].Dad].Len + 1; 521*e9a128d8SLei Wen if (bits > max_length) bits = max_length, overflow++; 522*e9a128d8SLei Wen tree[n].Len = (ush)bits; 523*e9a128d8SLei Wen /* We overwrite tree[n].Dad which is no longer needed */ 524*e9a128d8SLei Wen 525*e9a128d8SLei Wen if (n > max_code) continue; /* not a leaf node */ 526*e9a128d8SLei Wen 527*e9a128d8SLei Wen s->bl_count[bits]++; 528*e9a128d8SLei Wen xbits = 0; 529*e9a128d8SLei Wen if (n >= base) xbits = extra[n-base]; 530*e9a128d8SLei Wen f = tree[n].Freq; 531*e9a128d8SLei Wen s->opt_len += (ulg)f * (bits + xbits); 532*e9a128d8SLei Wen if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); 533*e9a128d8SLei Wen } 534*e9a128d8SLei Wen if (overflow == 0) return; 535*e9a128d8SLei Wen 536*e9a128d8SLei Wen Trace((stderr,"\nbit length overflow\n")); 537*e9a128d8SLei Wen /* This happens for example on obj2 and pic of the Calgary corpus */ 538*e9a128d8SLei Wen 539*e9a128d8SLei Wen /* Find the first bit length which could increase: */ 540*e9a128d8SLei Wen do { 541*e9a128d8SLei Wen bits = max_length-1; 542*e9a128d8SLei Wen while (s->bl_count[bits] == 0) bits--; 543*e9a128d8SLei Wen s->bl_count[bits]--; /* move one leaf down the tree */ 544*e9a128d8SLei Wen s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ 545*e9a128d8SLei Wen s->bl_count[max_length]--; 546*e9a128d8SLei Wen /* The brother of the overflow item also moves one step up, 547*e9a128d8SLei Wen * but this does not affect bl_count[max_length] 548*e9a128d8SLei Wen */ 549*e9a128d8SLei Wen overflow -= 2; 550*e9a128d8SLei Wen } while (overflow > 0); 551*e9a128d8SLei Wen 552*e9a128d8SLei Wen /* Now recompute all bit lengths, scanning in increasing frequency. 553*e9a128d8SLei Wen * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all 554*e9a128d8SLei Wen * lengths instead of fixing only the wrong ones. This idea is taken 555*e9a128d8SLei Wen * from 'ar' written by Haruhiko Okumura.) 556*e9a128d8SLei Wen */ 557*e9a128d8SLei Wen for (bits = max_length; bits != 0; bits--) { 558*e9a128d8SLei Wen n = s->bl_count[bits]; 559*e9a128d8SLei Wen while (n != 0) { 560*e9a128d8SLei Wen m = s->heap[--h]; 561*e9a128d8SLei Wen if (m > max_code) continue; 562*e9a128d8SLei Wen if ((unsigned) tree[m].Len != (unsigned) bits) { 563*e9a128d8SLei Wen Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); 564*e9a128d8SLei Wen s->opt_len += ((long)bits - (long)tree[m].Len) 565*e9a128d8SLei Wen *(long)tree[m].Freq; 566*e9a128d8SLei Wen tree[m].Len = (ush)bits; 567*e9a128d8SLei Wen } 568*e9a128d8SLei Wen n--; 569*e9a128d8SLei Wen } 570*e9a128d8SLei Wen } 571*e9a128d8SLei Wen } 572*e9a128d8SLei Wen 573*e9a128d8SLei Wen /* =========================================================================== 574*e9a128d8SLei Wen * Generate the codes for a given tree and bit counts (which need not be 575*e9a128d8SLei Wen * optimal). 576*e9a128d8SLei Wen * IN assertion: the array bl_count contains the bit length statistics for 577*e9a128d8SLei Wen * the given tree and the field len is set for all tree elements. 578*e9a128d8SLei Wen * OUT assertion: the field code is set for all tree elements of non 579*e9a128d8SLei Wen * zero code length. 580*e9a128d8SLei Wen */ 581*e9a128d8SLei Wen local void gen_codes (tree, max_code, bl_count) 582*e9a128d8SLei Wen ct_data *tree; /* the tree to decorate */ 583*e9a128d8SLei Wen int max_code; /* largest code with non zero frequency */ 584*e9a128d8SLei Wen ushf *bl_count; /* number of codes at each bit length */ 585*e9a128d8SLei Wen { 586*e9a128d8SLei Wen ush next_code[MAX_BITS+1]; /* next code value for each bit length */ 587*e9a128d8SLei Wen ush code = 0; /* running code value */ 588*e9a128d8SLei Wen int bits; /* bit index */ 589*e9a128d8SLei Wen int n; /* code index */ 590*e9a128d8SLei Wen 591*e9a128d8SLei Wen /* The distribution counts are first used to generate the code values 592*e9a128d8SLei Wen * without bit reversal. 593*e9a128d8SLei Wen */ 594*e9a128d8SLei Wen for (bits = 1; bits <= MAX_BITS; bits++) { 595*e9a128d8SLei Wen next_code[bits] = code = (code + bl_count[bits-1]) << 1; 596*e9a128d8SLei Wen } 597*e9a128d8SLei Wen /* Check that the bit counts in bl_count are consistent. The last code 598*e9a128d8SLei Wen * must be all ones. 599*e9a128d8SLei Wen */ 600*e9a128d8SLei Wen Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, 601*e9a128d8SLei Wen "inconsistent bit counts"); 602*e9a128d8SLei Wen Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); 603*e9a128d8SLei Wen 604*e9a128d8SLei Wen for (n = 0; n <= max_code; n++) { 605*e9a128d8SLei Wen int len = tree[n].Len; 606*e9a128d8SLei Wen if (len == 0) continue; 607*e9a128d8SLei Wen /* Now reverse the bits */ 608*e9a128d8SLei Wen tree[n].Code = bi_reverse(next_code[len]++, len); 609*e9a128d8SLei Wen 610*e9a128d8SLei Wen Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", 611*e9a128d8SLei Wen n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); 612*e9a128d8SLei Wen } 613*e9a128d8SLei Wen } 614*e9a128d8SLei Wen 615*e9a128d8SLei Wen /* =========================================================================== 616*e9a128d8SLei Wen * Construct one Huffman tree and assigns the code bit strings and lengths. 617*e9a128d8SLei Wen * Update the total bit length for the current block. 618*e9a128d8SLei Wen * IN assertion: the field freq is set for all tree elements. 619*e9a128d8SLei Wen * OUT assertions: the fields len and code are set to the optimal bit length 620*e9a128d8SLei Wen * and corresponding code. The length opt_len is updated; static_len is 621*e9a128d8SLei Wen * also updated if stree is not null. The field max_code is set. 622*e9a128d8SLei Wen */ 623*e9a128d8SLei Wen local void build_tree(s, desc) 624*e9a128d8SLei Wen deflate_state *s; 625*e9a128d8SLei Wen tree_desc *desc; /* the tree descriptor */ 626*e9a128d8SLei Wen { 627*e9a128d8SLei Wen ct_data *tree = desc->dyn_tree; 628*e9a128d8SLei Wen const ct_data *stree = desc->stat_desc->static_tree; 629*e9a128d8SLei Wen int elems = desc->stat_desc->elems; 630*e9a128d8SLei Wen int n, m; /* iterate over heap elements */ 631*e9a128d8SLei Wen int max_code = -1; /* largest code with non zero frequency */ 632*e9a128d8SLei Wen int node; /* new node being created */ 633*e9a128d8SLei Wen 634*e9a128d8SLei Wen /* Construct the initial heap, with least frequent element in 635*e9a128d8SLei Wen * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. 636*e9a128d8SLei Wen * heap[0] is not used. 637*e9a128d8SLei Wen */ 638*e9a128d8SLei Wen s->heap_len = 0, s->heap_max = HEAP_SIZE; 639*e9a128d8SLei Wen 640*e9a128d8SLei Wen for (n = 0; n < elems; n++) { 641*e9a128d8SLei Wen if (tree[n].Freq != 0) { 642*e9a128d8SLei Wen s->heap[++(s->heap_len)] = max_code = n; 643*e9a128d8SLei Wen s->depth[n] = 0; 644*e9a128d8SLei Wen } else { 645*e9a128d8SLei Wen tree[n].Len = 0; 646*e9a128d8SLei Wen } 647*e9a128d8SLei Wen } 648*e9a128d8SLei Wen 649*e9a128d8SLei Wen /* The pkzip format requires that at least one distance code exists, 650*e9a128d8SLei Wen * and that at least one bit should be sent even if there is only one 651*e9a128d8SLei Wen * possible code. So to avoid special checks later on we force at least 652*e9a128d8SLei Wen * two codes of non zero frequency. 653*e9a128d8SLei Wen */ 654*e9a128d8SLei Wen while (s->heap_len < 2) { 655*e9a128d8SLei Wen node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); 656*e9a128d8SLei Wen tree[node].Freq = 1; 657*e9a128d8SLei Wen s->depth[node] = 0; 658*e9a128d8SLei Wen s->opt_len--; if (stree) s->static_len -= stree[node].Len; 659*e9a128d8SLei Wen /* node is 0 or 1 so it does not have extra bits */ 660*e9a128d8SLei Wen } 661*e9a128d8SLei Wen desc->max_code = max_code; 662*e9a128d8SLei Wen 663*e9a128d8SLei Wen /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, 664*e9a128d8SLei Wen * establish sub-heaps of increasing lengths: 665*e9a128d8SLei Wen */ 666*e9a128d8SLei Wen for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); 667*e9a128d8SLei Wen 668*e9a128d8SLei Wen /* Construct the Huffman tree by repeatedly combining the least two 669*e9a128d8SLei Wen * frequent nodes. 670*e9a128d8SLei Wen */ 671*e9a128d8SLei Wen node = elems; /* next internal node of the tree */ 672*e9a128d8SLei Wen do { 673*e9a128d8SLei Wen pqremove(s, tree, n); /* n = node of least frequency */ 674*e9a128d8SLei Wen m = s->heap[SMALLEST]; /* m = node of next least frequency */ 675*e9a128d8SLei Wen 676*e9a128d8SLei Wen s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ 677*e9a128d8SLei Wen s->heap[--(s->heap_max)] = m; 678*e9a128d8SLei Wen 679*e9a128d8SLei Wen /* Create a new node father of n and m */ 680*e9a128d8SLei Wen tree[node].Freq = tree[n].Freq + tree[m].Freq; 681*e9a128d8SLei Wen s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? 682*e9a128d8SLei Wen s->depth[n] : s->depth[m]) + 1); 683*e9a128d8SLei Wen tree[n].Dad = tree[m].Dad = (ush)node; 684*e9a128d8SLei Wen #ifdef DUMP_BL_TREE 685*e9a128d8SLei Wen if (tree == s->bl_tree) { 686*e9a128d8SLei Wen fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", 687*e9a128d8SLei Wen node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); 688*e9a128d8SLei Wen } 689*e9a128d8SLei Wen #endif 690*e9a128d8SLei Wen /* and insert the new node in the heap */ 691*e9a128d8SLei Wen s->heap[SMALLEST] = node++; 692*e9a128d8SLei Wen pqdownheap(s, tree, SMALLEST); 693*e9a128d8SLei Wen 694*e9a128d8SLei Wen } while (s->heap_len >= 2); 695*e9a128d8SLei Wen 696*e9a128d8SLei Wen s->heap[--(s->heap_max)] = s->heap[SMALLEST]; 697*e9a128d8SLei Wen 698*e9a128d8SLei Wen /* At this point, the fields freq and dad are set. We can now 699*e9a128d8SLei Wen * generate the bit lengths. 700*e9a128d8SLei Wen */ 701*e9a128d8SLei Wen gen_bitlen(s, (tree_desc *)desc); 702*e9a128d8SLei Wen 703*e9a128d8SLei Wen /* The field len is now set, we can generate the bit codes */ 704*e9a128d8SLei Wen gen_codes ((ct_data *)tree, max_code, s->bl_count); 705*e9a128d8SLei Wen } 706*e9a128d8SLei Wen 707*e9a128d8SLei Wen /* =========================================================================== 708*e9a128d8SLei Wen * Scan a literal or distance tree to determine the frequencies of the codes 709*e9a128d8SLei Wen * in the bit length tree. 710*e9a128d8SLei Wen */ 711*e9a128d8SLei Wen local void scan_tree (s, tree, max_code) 712*e9a128d8SLei Wen deflate_state *s; 713*e9a128d8SLei Wen ct_data *tree; /* the tree to be scanned */ 714*e9a128d8SLei Wen int max_code; /* and its largest code of non zero frequency */ 715*e9a128d8SLei Wen { 716*e9a128d8SLei Wen int n; /* iterates over all tree elements */ 717*e9a128d8SLei Wen int prevlen = -1; /* last emitted length */ 718*e9a128d8SLei Wen int curlen; /* length of current code */ 719*e9a128d8SLei Wen int nextlen = tree[0].Len; /* length of next code */ 720*e9a128d8SLei Wen int count = 0; /* repeat count of the current code */ 721*e9a128d8SLei Wen int max_count = 7; /* max repeat count */ 722*e9a128d8SLei Wen int min_count = 4; /* min repeat count */ 723*e9a128d8SLei Wen 724*e9a128d8SLei Wen if (nextlen == 0) max_count = 138, min_count = 3; 725*e9a128d8SLei Wen tree[max_code+1].Len = (ush)0xffff; /* guard */ 726*e9a128d8SLei Wen 727*e9a128d8SLei Wen for (n = 0; n <= max_code; n++) { 728*e9a128d8SLei Wen curlen = nextlen; nextlen = tree[n+1].Len; 729*e9a128d8SLei Wen if (++count < max_count && curlen == nextlen) { 730*e9a128d8SLei Wen continue; 731*e9a128d8SLei Wen } else if (count < min_count) { 732*e9a128d8SLei Wen s->bl_tree[curlen].Freq += count; 733*e9a128d8SLei Wen } else if (curlen != 0) { 734*e9a128d8SLei Wen if (curlen != prevlen) s->bl_tree[curlen].Freq++; 735*e9a128d8SLei Wen s->bl_tree[REP_3_6].Freq++; 736*e9a128d8SLei Wen } else if (count <= 10) { 737*e9a128d8SLei Wen s->bl_tree[REPZ_3_10].Freq++; 738*e9a128d8SLei Wen } else { 739*e9a128d8SLei Wen s->bl_tree[REPZ_11_138].Freq++; 740*e9a128d8SLei Wen } 741*e9a128d8SLei Wen count = 0; prevlen = curlen; 742*e9a128d8SLei Wen if (nextlen == 0) { 743*e9a128d8SLei Wen max_count = 138, min_count = 3; 744*e9a128d8SLei Wen } else if (curlen == nextlen) { 745*e9a128d8SLei Wen max_count = 6, min_count = 3; 746*e9a128d8SLei Wen } else { 747*e9a128d8SLei Wen max_count = 7, min_count = 4; 748*e9a128d8SLei Wen } 749*e9a128d8SLei Wen } 750*e9a128d8SLei Wen } 751*e9a128d8SLei Wen 752*e9a128d8SLei Wen /* =========================================================================== 753*e9a128d8SLei Wen * Send a literal or distance tree in compressed form, using the codes in 754*e9a128d8SLei Wen * bl_tree. 755*e9a128d8SLei Wen */ 756*e9a128d8SLei Wen local void send_tree (s, tree, max_code) 757*e9a128d8SLei Wen deflate_state *s; 758*e9a128d8SLei Wen ct_data *tree; /* the tree to be scanned */ 759*e9a128d8SLei Wen int max_code; /* and its largest code of non zero frequency */ 760*e9a128d8SLei Wen { 761*e9a128d8SLei Wen int n; /* iterates over all tree elements */ 762*e9a128d8SLei Wen int prevlen = -1; /* last emitted length */ 763*e9a128d8SLei Wen int curlen; /* length of current code */ 764*e9a128d8SLei Wen int nextlen = tree[0].Len; /* length of next code */ 765*e9a128d8SLei Wen int count = 0; /* repeat count of the current code */ 766*e9a128d8SLei Wen int max_count = 7; /* max repeat count */ 767*e9a128d8SLei Wen int min_count = 4; /* min repeat count */ 768*e9a128d8SLei Wen 769*e9a128d8SLei Wen /* tree[max_code+1].Len = -1; */ /* guard already set */ 770*e9a128d8SLei Wen if (nextlen == 0) max_count = 138, min_count = 3; 771*e9a128d8SLei Wen 772*e9a128d8SLei Wen for (n = 0; n <= max_code; n++) { 773*e9a128d8SLei Wen curlen = nextlen; nextlen = tree[n+1].Len; 774*e9a128d8SLei Wen if (++count < max_count && curlen == nextlen) { 775*e9a128d8SLei Wen continue; 776*e9a128d8SLei Wen } else if (count < min_count) { 777*e9a128d8SLei Wen do { send_code(s, curlen, s->bl_tree); } while (--count != 0); 778*e9a128d8SLei Wen 779*e9a128d8SLei Wen } else if (curlen != 0) { 780*e9a128d8SLei Wen if (curlen != prevlen) { 781*e9a128d8SLei Wen send_code(s, curlen, s->bl_tree); count--; 782*e9a128d8SLei Wen } 783*e9a128d8SLei Wen Assert(count >= 3 && count <= 6, " 3_6?"); 784*e9a128d8SLei Wen send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); 785*e9a128d8SLei Wen 786*e9a128d8SLei Wen } else if (count <= 10) { 787*e9a128d8SLei Wen send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); 788*e9a128d8SLei Wen 789*e9a128d8SLei Wen } else { 790*e9a128d8SLei Wen send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); 791*e9a128d8SLei Wen } 792*e9a128d8SLei Wen count = 0; prevlen = curlen; 793*e9a128d8SLei Wen if (nextlen == 0) { 794*e9a128d8SLei Wen max_count = 138, min_count = 3; 795*e9a128d8SLei Wen } else if (curlen == nextlen) { 796*e9a128d8SLei Wen max_count = 6, min_count = 3; 797*e9a128d8SLei Wen } else { 798*e9a128d8SLei Wen max_count = 7, min_count = 4; 799*e9a128d8SLei Wen } 800*e9a128d8SLei Wen } 801*e9a128d8SLei Wen } 802*e9a128d8SLei Wen 803*e9a128d8SLei Wen /* =========================================================================== 804*e9a128d8SLei Wen * Construct the Huffman tree for the bit lengths and return the index in 805*e9a128d8SLei Wen * bl_order of the last bit length code to send. 806*e9a128d8SLei Wen */ 807*e9a128d8SLei Wen local int build_bl_tree(s) 808*e9a128d8SLei Wen deflate_state *s; 809*e9a128d8SLei Wen { 810*e9a128d8SLei Wen int max_blindex; /* index of last bit length code of non zero freq */ 811*e9a128d8SLei Wen 812*e9a128d8SLei Wen /* Determine the bit length frequencies for literal and distance trees */ 813*e9a128d8SLei Wen scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); 814*e9a128d8SLei Wen scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); 815*e9a128d8SLei Wen 816*e9a128d8SLei Wen /* Build the bit length tree: */ 817*e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->bl_desc))); 818*e9a128d8SLei Wen /* opt_len now includes the length of the tree representations, except 819*e9a128d8SLei Wen * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. 820*e9a128d8SLei Wen */ 821*e9a128d8SLei Wen 822*e9a128d8SLei Wen /* Determine the number of bit length codes to send. The pkzip format 823*e9a128d8SLei Wen * requires that at least 4 bit length codes be sent. (appnote.txt says 824*e9a128d8SLei Wen * 3 but the actual value used is 4.) 825*e9a128d8SLei Wen */ 826*e9a128d8SLei Wen for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { 827*e9a128d8SLei Wen if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; 828*e9a128d8SLei Wen } 829*e9a128d8SLei Wen /* Update opt_len to include the bit length tree and counts */ 830*e9a128d8SLei Wen s->opt_len += 3*(max_blindex+1) + 5+5+4; 831*e9a128d8SLei Wen Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", 832*e9a128d8SLei Wen s->opt_len, s->static_len)); 833*e9a128d8SLei Wen 834*e9a128d8SLei Wen return max_blindex; 835*e9a128d8SLei Wen } 836*e9a128d8SLei Wen 837*e9a128d8SLei Wen /* =========================================================================== 838*e9a128d8SLei Wen * Send the header for a block using dynamic Huffman trees: the counts, the 839*e9a128d8SLei Wen * lengths of the bit length codes, the literal tree and the distance tree. 840*e9a128d8SLei Wen * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. 841*e9a128d8SLei Wen */ 842*e9a128d8SLei Wen local void send_all_trees(s, lcodes, dcodes, blcodes) 843*e9a128d8SLei Wen deflate_state *s; 844*e9a128d8SLei Wen int lcodes, dcodes, blcodes; /* number of codes for each tree */ 845*e9a128d8SLei Wen { 846*e9a128d8SLei Wen int rank; /* index in bl_order */ 847*e9a128d8SLei Wen 848*e9a128d8SLei Wen Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); 849*e9a128d8SLei Wen Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, 850*e9a128d8SLei Wen "too many codes"); 851*e9a128d8SLei Wen Tracev((stderr, "\nbl counts: ")); 852*e9a128d8SLei Wen send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ 853*e9a128d8SLei Wen send_bits(s, dcodes-1, 5); 854*e9a128d8SLei Wen send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ 855*e9a128d8SLei Wen for (rank = 0; rank < blcodes; rank++) { 856*e9a128d8SLei Wen Tracev((stderr, "\nbl code %2d ", bl_order[rank])); 857*e9a128d8SLei Wen send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); 858*e9a128d8SLei Wen } 859*e9a128d8SLei Wen Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); 860*e9a128d8SLei Wen 861*e9a128d8SLei Wen send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ 862*e9a128d8SLei Wen Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); 863*e9a128d8SLei Wen 864*e9a128d8SLei Wen send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ 865*e9a128d8SLei Wen Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); 866*e9a128d8SLei Wen } 867*e9a128d8SLei Wen 868*e9a128d8SLei Wen /* =========================================================================== 869*e9a128d8SLei Wen * Send a stored block 870*e9a128d8SLei Wen */ 871*e9a128d8SLei Wen void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last) 872*e9a128d8SLei Wen deflate_state *s; 873*e9a128d8SLei Wen charf *buf; /* input block */ 874*e9a128d8SLei Wen ulg stored_len; /* length of input block */ 875*e9a128d8SLei Wen int last; /* one if this is the last block for a file */ 876*e9a128d8SLei Wen { 877*e9a128d8SLei Wen send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */ 878*e9a128d8SLei Wen #ifdef DEBUG 879*e9a128d8SLei Wen s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; 880*e9a128d8SLei Wen s->compressed_len += (stored_len + 4) << 3; 881*e9a128d8SLei Wen #endif 882*e9a128d8SLei Wen copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ 883*e9a128d8SLei Wen } 884*e9a128d8SLei Wen 885*e9a128d8SLei Wen /* =========================================================================== 886*e9a128d8SLei Wen * Send one empty static block to give enough lookahead for inflate. 887*e9a128d8SLei Wen * This takes 10 bits, of which 7 may remain in the bit buffer. 888*e9a128d8SLei Wen * The current inflate code requires 9 bits of lookahead. If the 889*e9a128d8SLei Wen * last two codes for the previous block (real code plus EOB) were coded 890*e9a128d8SLei Wen * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode 891*e9a128d8SLei Wen * the last real code. In this case we send two empty static blocks instead 892*e9a128d8SLei Wen * of one. (There are no problems if the previous block is stored or fixed.) 893*e9a128d8SLei Wen * To simplify the code, we assume the worst case of last real code encoded 894*e9a128d8SLei Wen * on one bit only. 895*e9a128d8SLei Wen */ 896*e9a128d8SLei Wen void ZLIB_INTERNAL _tr_align(s) 897*e9a128d8SLei Wen deflate_state *s; 898*e9a128d8SLei Wen { 899*e9a128d8SLei Wen send_bits(s, STATIC_TREES<<1, 3); 900*e9a128d8SLei Wen send_code(s, END_BLOCK, static_ltree); 901*e9a128d8SLei Wen #ifdef DEBUG 902*e9a128d8SLei Wen s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ 903*e9a128d8SLei Wen #endif 904*e9a128d8SLei Wen bi_flush(s); 905*e9a128d8SLei Wen /* Of the 10 bits for the empty block, we have already sent 906*e9a128d8SLei Wen * (10 - bi_valid) bits. The lookahead for the last real code (before 907*e9a128d8SLei Wen * the EOB of the previous block) was thus at least one plus the length 908*e9a128d8SLei Wen * of the EOB plus what we have just sent of the empty static block. 909*e9a128d8SLei Wen */ 910*e9a128d8SLei Wen if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { 911*e9a128d8SLei Wen send_bits(s, STATIC_TREES<<1, 3); 912*e9a128d8SLei Wen send_code(s, END_BLOCK, static_ltree); 913*e9a128d8SLei Wen #ifdef DEBUG 914*e9a128d8SLei Wen s->compressed_len += 10L; 915*e9a128d8SLei Wen #endif 916*e9a128d8SLei Wen bi_flush(s); 917*e9a128d8SLei Wen } 918*e9a128d8SLei Wen s->last_eob_len = 7; 919*e9a128d8SLei Wen } 920*e9a128d8SLei Wen 921*e9a128d8SLei Wen /* =========================================================================== 922*e9a128d8SLei Wen * Determine the best encoding for the current block: dynamic trees, static 923*e9a128d8SLei Wen * trees or store, and output the encoded block to the zip file. 924*e9a128d8SLei Wen */ 925*e9a128d8SLei Wen void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) 926*e9a128d8SLei Wen deflate_state *s; 927*e9a128d8SLei Wen charf *buf; /* input block, or NULL if too old */ 928*e9a128d8SLei Wen ulg stored_len; /* length of input block */ 929*e9a128d8SLei Wen int last; /* one if this is the last block for a file */ 930*e9a128d8SLei Wen { 931*e9a128d8SLei Wen ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ 932*e9a128d8SLei Wen int max_blindex = 0; /* index of last bit length code of non zero freq */ 933*e9a128d8SLei Wen 934*e9a128d8SLei Wen /* Build the Huffman trees unless a stored block is forced */ 935*e9a128d8SLei Wen if (s->level > 0) { 936*e9a128d8SLei Wen 937*e9a128d8SLei Wen /* Check if the file is binary or text */ 938*e9a128d8SLei Wen if (s->strm->data_type == Z_UNKNOWN) 939*e9a128d8SLei Wen s->strm->data_type = detect_data_type(s); 940*e9a128d8SLei Wen 941*e9a128d8SLei Wen /* Construct the literal and distance trees */ 942*e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->l_desc))); 943*e9a128d8SLei Wen Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, 944*e9a128d8SLei Wen s->static_len)); 945*e9a128d8SLei Wen 946*e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->d_desc))); 947*e9a128d8SLei Wen Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, 948*e9a128d8SLei Wen s->static_len)); 949*e9a128d8SLei Wen /* At this point, opt_len and static_len are the total bit lengths of 950*e9a128d8SLei Wen * the compressed block data, excluding the tree representations. 951*e9a128d8SLei Wen */ 952*e9a128d8SLei Wen 953*e9a128d8SLei Wen /* Build the bit length tree for the above two trees, and get the index 954*e9a128d8SLei Wen * in bl_order of the last bit length code to send. 955*e9a128d8SLei Wen */ 956*e9a128d8SLei Wen max_blindex = build_bl_tree(s); 957*e9a128d8SLei Wen 958*e9a128d8SLei Wen /* Determine the best encoding. Compute the block lengths in bytes. */ 959*e9a128d8SLei Wen opt_lenb = (s->opt_len+3+7)>>3; 960*e9a128d8SLei Wen static_lenb = (s->static_len+3+7)>>3; 961*e9a128d8SLei Wen 962*e9a128d8SLei Wen Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", 963*e9a128d8SLei Wen opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, 964*e9a128d8SLei Wen s->last_lit)); 965*e9a128d8SLei Wen 966*e9a128d8SLei Wen if (static_lenb <= opt_lenb) opt_lenb = static_lenb; 967*e9a128d8SLei Wen 968*e9a128d8SLei Wen } else { 969*e9a128d8SLei Wen Assert(buf != (char*)0, "lost buf"); 970*e9a128d8SLei Wen opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ 971*e9a128d8SLei Wen } 972*e9a128d8SLei Wen 973*e9a128d8SLei Wen #ifdef FORCE_STORED 974*e9a128d8SLei Wen if (buf != (char*)0) { /* force stored block */ 975*e9a128d8SLei Wen #else 976*e9a128d8SLei Wen if (stored_len+4 <= opt_lenb && buf != (char*)0) { 977*e9a128d8SLei Wen /* 4: two words for the lengths */ 978*e9a128d8SLei Wen #endif 979*e9a128d8SLei Wen /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. 980*e9a128d8SLei Wen * Otherwise we can't have processed more than WSIZE input bytes since 981*e9a128d8SLei Wen * the last block flush, because compression would have been 982*e9a128d8SLei Wen * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to 983*e9a128d8SLei Wen * transform a block into a stored block. 984*e9a128d8SLei Wen */ 985*e9a128d8SLei Wen _tr_stored_block(s, buf, stored_len, last); 986*e9a128d8SLei Wen 987*e9a128d8SLei Wen #ifdef FORCE_STATIC 988*e9a128d8SLei Wen } else if (static_lenb >= 0) { /* force static trees */ 989*e9a128d8SLei Wen #else 990*e9a128d8SLei Wen } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { 991*e9a128d8SLei Wen #endif 992*e9a128d8SLei Wen send_bits(s, (STATIC_TREES<<1)+last, 3); 993*e9a128d8SLei Wen compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); 994*e9a128d8SLei Wen #ifdef DEBUG 995*e9a128d8SLei Wen s->compressed_len += 3 + s->static_len; 996*e9a128d8SLei Wen #endif 997*e9a128d8SLei Wen } else { 998*e9a128d8SLei Wen send_bits(s, (DYN_TREES<<1)+last, 3); 999*e9a128d8SLei Wen send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, 1000*e9a128d8SLei Wen max_blindex+1); 1001*e9a128d8SLei Wen compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); 1002*e9a128d8SLei Wen #ifdef DEBUG 1003*e9a128d8SLei Wen s->compressed_len += 3 + s->opt_len; 1004*e9a128d8SLei Wen #endif 1005*e9a128d8SLei Wen } 1006*e9a128d8SLei Wen Assert (s->compressed_len == s->bits_sent, "bad compressed size"); 1007*e9a128d8SLei Wen /* The above check is made mod 2^32, for files larger than 512 MB 1008*e9a128d8SLei Wen * and uLong implemented on 32 bits. 1009*e9a128d8SLei Wen */ 1010*e9a128d8SLei Wen init_block(s); 1011*e9a128d8SLei Wen 1012*e9a128d8SLei Wen if (last) { 1013*e9a128d8SLei Wen bi_windup(s); 1014*e9a128d8SLei Wen #ifdef DEBUG 1015*e9a128d8SLei Wen s->compressed_len += 7; /* align on byte boundary */ 1016*e9a128d8SLei Wen #endif 1017*e9a128d8SLei Wen } 1018*e9a128d8SLei Wen Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, 1019*e9a128d8SLei Wen s->compressed_len-7*last)); 1020*e9a128d8SLei Wen } 1021*e9a128d8SLei Wen 1022*e9a128d8SLei Wen /* =========================================================================== 1023*e9a128d8SLei Wen * Save the match info and tally the frequency counts. Return true if 1024*e9a128d8SLei Wen * the current block must be flushed. 1025*e9a128d8SLei Wen */ 1026*e9a128d8SLei Wen int ZLIB_INTERNAL _tr_tally (s, dist, lc) 1027*e9a128d8SLei Wen deflate_state *s; 1028*e9a128d8SLei Wen unsigned dist; /* distance of matched string */ 1029*e9a128d8SLei Wen unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ 1030*e9a128d8SLei Wen { 1031*e9a128d8SLei Wen s->d_buf[s->last_lit] = (ush)dist; 1032*e9a128d8SLei Wen s->l_buf[s->last_lit++] = (uch)lc; 1033*e9a128d8SLei Wen if (dist == 0) { 1034*e9a128d8SLei Wen /* lc is the unmatched char */ 1035*e9a128d8SLei Wen s->dyn_ltree[lc].Freq++; 1036*e9a128d8SLei Wen } else { 1037*e9a128d8SLei Wen s->matches++; 1038*e9a128d8SLei Wen /* Here, lc is the match length - MIN_MATCH */ 1039*e9a128d8SLei Wen dist--; /* dist = match distance - 1 */ 1040*e9a128d8SLei Wen Assert((ush)dist < (ush)MAX_DIST(s) && 1041*e9a128d8SLei Wen (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && 1042*e9a128d8SLei Wen (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); 1043*e9a128d8SLei Wen 1044*e9a128d8SLei Wen s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; 1045*e9a128d8SLei Wen s->dyn_dtree[d_code(dist)].Freq++; 1046*e9a128d8SLei Wen } 1047*e9a128d8SLei Wen 1048*e9a128d8SLei Wen #ifdef TRUNCATE_BLOCK 1049*e9a128d8SLei Wen /* Try to guess if it is profitable to stop the current block here */ 1050*e9a128d8SLei Wen if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { 1051*e9a128d8SLei Wen /* Compute an upper bound for the compressed length */ 1052*e9a128d8SLei Wen ulg out_length = (ulg)s->last_lit*8L; 1053*e9a128d8SLei Wen ulg in_length = (ulg)((long)s->strstart - s->block_start); 1054*e9a128d8SLei Wen int dcode; 1055*e9a128d8SLei Wen for (dcode = 0; dcode < D_CODES; dcode++) { 1056*e9a128d8SLei Wen out_length += (ulg)s->dyn_dtree[dcode].Freq * 1057*e9a128d8SLei Wen (5L+extra_dbits[dcode]); 1058*e9a128d8SLei Wen } 1059*e9a128d8SLei Wen out_length >>= 3; 1060*e9a128d8SLei Wen Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", 1061*e9a128d8SLei Wen s->last_lit, in_length, out_length, 1062*e9a128d8SLei Wen 100L - out_length*100L/in_length)); 1063*e9a128d8SLei Wen if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; 1064*e9a128d8SLei Wen } 1065*e9a128d8SLei Wen #endif 1066*e9a128d8SLei Wen return (s->last_lit == s->lit_bufsize-1); 1067*e9a128d8SLei Wen /* We avoid equality with lit_bufsize because of wraparound at 64K 1068*e9a128d8SLei Wen * on 16 bit machines and because stored blocks are restricted to 1069*e9a128d8SLei Wen * 64K-1 bytes. 1070*e9a128d8SLei Wen */ 1071*e9a128d8SLei Wen } 1072*e9a128d8SLei Wen 1073*e9a128d8SLei Wen /* =========================================================================== 1074*e9a128d8SLei Wen * Send the block data compressed using the given Huffman trees 1075*e9a128d8SLei Wen */ 1076*e9a128d8SLei Wen local void compress_block(s, ltree, dtree) 1077*e9a128d8SLei Wen deflate_state *s; 1078*e9a128d8SLei Wen ct_data *ltree; /* literal tree */ 1079*e9a128d8SLei Wen ct_data *dtree; /* distance tree */ 1080*e9a128d8SLei Wen { 1081*e9a128d8SLei Wen unsigned dist; /* distance of matched string */ 1082*e9a128d8SLei Wen int lc; /* match length or unmatched char (if dist == 0) */ 1083*e9a128d8SLei Wen unsigned lx = 0; /* running index in l_buf */ 1084*e9a128d8SLei Wen unsigned code; /* the code to send */ 1085*e9a128d8SLei Wen int extra; /* number of extra bits to send */ 1086*e9a128d8SLei Wen 1087*e9a128d8SLei Wen if (s->last_lit != 0) do { 1088*e9a128d8SLei Wen dist = s->d_buf[lx]; 1089*e9a128d8SLei Wen lc = s->l_buf[lx++]; 1090*e9a128d8SLei Wen if (dist == 0) { 1091*e9a128d8SLei Wen send_code(s, lc, ltree); /* send a literal byte */ 1092*e9a128d8SLei Wen Tracecv(isgraph(lc), (stderr," '%c' ", lc)); 1093*e9a128d8SLei Wen } else { 1094*e9a128d8SLei Wen /* Here, lc is the match length - MIN_MATCH */ 1095*e9a128d8SLei Wen code = _length_code[lc]; 1096*e9a128d8SLei Wen send_code(s, code+LITERALS+1, ltree); /* send the length code */ 1097*e9a128d8SLei Wen extra = extra_lbits[code]; 1098*e9a128d8SLei Wen if (extra != 0) { 1099*e9a128d8SLei Wen lc -= base_length[code]; 1100*e9a128d8SLei Wen send_bits(s, lc, extra); /* send the extra length bits */ 1101*e9a128d8SLei Wen } 1102*e9a128d8SLei Wen dist--; /* dist is now the match distance - 1 */ 1103*e9a128d8SLei Wen code = d_code(dist); 1104*e9a128d8SLei Wen Assert (code < D_CODES, "bad d_code"); 1105*e9a128d8SLei Wen 1106*e9a128d8SLei Wen send_code(s, code, dtree); /* send the distance code */ 1107*e9a128d8SLei Wen extra = extra_dbits[code]; 1108*e9a128d8SLei Wen if (extra != 0) { 1109*e9a128d8SLei Wen dist -= base_dist[code]; 1110*e9a128d8SLei Wen send_bits(s, dist, extra); /* send the extra distance bits */ 1111*e9a128d8SLei Wen } 1112*e9a128d8SLei Wen } /* literal or match pair ? */ 1113*e9a128d8SLei Wen 1114*e9a128d8SLei Wen /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ 1115*e9a128d8SLei Wen Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, 1116*e9a128d8SLei Wen "pendingBuf overflow"); 1117*e9a128d8SLei Wen 1118*e9a128d8SLei Wen } while (lx < s->last_lit); 1119*e9a128d8SLei Wen 1120*e9a128d8SLei Wen send_code(s, END_BLOCK, ltree); 1121*e9a128d8SLei Wen s->last_eob_len = ltree[END_BLOCK].Len; 1122*e9a128d8SLei Wen } 1123*e9a128d8SLei Wen 1124*e9a128d8SLei Wen /* =========================================================================== 1125*e9a128d8SLei Wen * Check if the data type is TEXT or BINARY, using the following algorithm: 1126*e9a128d8SLei Wen * - TEXT if the two conditions below are satisfied: 1127*e9a128d8SLei Wen * a) There are no non-portable control characters belonging to the 1128*e9a128d8SLei Wen * "black list" (0..6, 14..25, 28..31). 1129*e9a128d8SLei Wen * b) There is at least one printable character belonging to the 1130*e9a128d8SLei Wen * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). 1131*e9a128d8SLei Wen * - BINARY otherwise. 1132*e9a128d8SLei Wen * - The following partially-portable control characters form a 1133*e9a128d8SLei Wen * "gray list" that is ignored in this detection algorithm: 1134*e9a128d8SLei Wen * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). 1135*e9a128d8SLei Wen * IN assertion: the fields Freq of dyn_ltree are set. 1136*e9a128d8SLei Wen */ 1137*e9a128d8SLei Wen local int detect_data_type(s) 1138*e9a128d8SLei Wen deflate_state *s; 1139*e9a128d8SLei Wen { 1140*e9a128d8SLei Wen /* black_mask is the bit mask of black-listed bytes 1141*e9a128d8SLei Wen * set bits 0..6, 14..25, and 28..31 1142*e9a128d8SLei Wen * 0xf3ffc07f = binary 11110011111111111100000001111111 1143*e9a128d8SLei Wen */ 1144*e9a128d8SLei Wen unsigned long black_mask = 0xf3ffc07fUL; 1145*e9a128d8SLei Wen int n; 1146*e9a128d8SLei Wen 1147*e9a128d8SLei Wen /* Check for non-textual ("black-listed") bytes. */ 1148*e9a128d8SLei Wen for (n = 0; n <= 31; n++, black_mask >>= 1) 1149*e9a128d8SLei Wen if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0)) 1150*e9a128d8SLei Wen return Z_BINARY; 1151*e9a128d8SLei Wen 1152*e9a128d8SLei Wen /* Check for textual ("white-listed") bytes. */ 1153*e9a128d8SLei Wen if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0 1154*e9a128d8SLei Wen || s->dyn_ltree[13].Freq != 0) 1155*e9a128d8SLei Wen return Z_TEXT; 1156*e9a128d8SLei Wen for (n = 32; n < LITERALS; n++) 1157*e9a128d8SLei Wen if (s->dyn_ltree[n].Freq != 0) 1158*e9a128d8SLei Wen return Z_TEXT; 1159*e9a128d8SLei Wen 1160*e9a128d8SLei Wen /* There are no "black-listed" or "white-listed" bytes: 1161*e9a128d8SLei Wen * this stream either is empty or has tolerated ("gray-listed") bytes only. 1162*e9a128d8SLei Wen */ 1163*e9a128d8SLei Wen return Z_BINARY; 1164*e9a128d8SLei Wen } 1165*e9a128d8SLei Wen 1166*e9a128d8SLei Wen /* =========================================================================== 1167*e9a128d8SLei Wen * Reverse the first len bits of a code, using straightforward code (a faster 1168*e9a128d8SLei Wen * method would use a table) 1169*e9a128d8SLei Wen * IN assertion: 1 <= len <= 15 1170*e9a128d8SLei Wen */ 1171*e9a128d8SLei Wen local unsigned bi_reverse(code, len) 1172*e9a128d8SLei Wen unsigned code; /* the value to invert */ 1173*e9a128d8SLei Wen int len; /* its bit length */ 1174*e9a128d8SLei Wen { 1175*e9a128d8SLei Wen register unsigned res = 0; 1176*e9a128d8SLei Wen do { 1177*e9a128d8SLei Wen res |= code & 1; 1178*e9a128d8SLei Wen code >>= 1, res <<= 1; 1179*e9a128d8SLei Wen } while (--len > 0); 1180*e9a128d8SLei Wen return res >> 1; 1181*e9a128d8SLei Wen } 1182*e9a128d8SLei Wen 1183*e9a128d8SLei Wen /* =========================================================================== 1184*e9a128d8SLei Wen * Flush the bit buffer, keeping at most 7 bits in it. 1185*e9a128d8SLei Wen */ 1186*e9a128d8SLei Wen local void bi_flush(s) 1187*e9a128d8SLei Wen deflate_state *s; 1188*e9a128d8SLei Wen { 1189*e9a128d8SLei Wen if (s->bi_valid == 16) { 1190*e9a128d8SLei Wen put_short(s, s->bi_buf); 1191*e9a128d8SLei Wen s->bi_buf = 0; 1192*e9a128d8SLei Wen s->bi_valid = 0; 1193*e9a128d8SLei Wen } else if (s->bi_valid >= 8) { 1194*e9a128d8SLei Wen put_byte(s, (Byte)s->bi_buf); 1195*e9a128d8SLei Wen s->bi_buf >>= 8; 1196*e9a128d8SLei Wen s->bi_valid -= 8; 1197*e9a128d8SLei Wen } 1198*e9a128d8SLei Wen } 1199*e9a128d8SLei Wen 1200*e9a128d8SLei Wen /* =========================================================================== 1201*e9a128d8SLei Wen * Flush the bit buffer and align the output on a byte boundary 1202*e9a128d8SLei Wen */ 1203*e9a128d8SLei Wen local void bi_windup(s) 1204*e9a128d8SLei Wen deflate_state *s; 1205*e9a128d8SLei Wen { 1206*e9a128d8SLei Wen if (s->bi_valid > 8) { 1207*e9a128d8SLei Wen put_short(s, s->bi_buf); 1208*e9a128d8SLei Wen } else if (s->bi_valid > 0) { 1209*e9a128d8SLei Wen put_byte(s, (Byte)s->bi_buf); 1210*e9a128d8SLei Wen } 1211*e9a128d8SLei Wen s->bi_buf = 0; 1212*e9a128d8SLei Wen s->bi_valid = 0; 1213*e9a128d8SLei Wen #ifdef DEBUG 1214*e9a128d8SLei Wen s->bits_sent = (s->bits_sent+7) & ~7; 1215*e9a128d8SLei Wen #endif 1216*e9a128d8SLei Wen } 1217*e9a128d8SLei Wen 1218*e9a128d8SLei Wen /* =========================================================================== 1219*e9a128d8SLei Wen * Copy a stored block, storing first the length and its 1220*e9a128d8SLei Wen * one's complement if requested. 1221*e9a128d8SLei Wen */ 1222*e9a128d8SLei Wen local void copy_block(s, buf, len, header) 1223*e9a128d8SLei Wen deflate_state *s; 1224*e9a128d8SLei Wen charf *buf; /* the input data */ 1225*e9a128d8SLei Wen unsigned len; /* its length */ 1226*e9a128d8SLei Wen int header; /* true if block header must be written */ 1227*e9a128d8SLei Wen { 1228*e9a128d8SLei Wen bi_windup(s); /* align on byte boundary */ 1229*e9a128d8SLei Wen s->last_eob_len = 8; /* enough lookahead for inflate */ 1230*e9a128d8SLei Wen 1231*e9a128d8SLei Wen if (header) { 1232*e9a128d8SLei Wen put_short(s, (ush)len); 1233*e9a128d8SLei Wen put_short(s, (ush)~len); 1234*e9a128d8SLei Wen #ifdef DEBUG 1235*e9a128d8SLei Wen s->bits_sent += 2*16; 1236*e9a128d8SLei Wen #endif 1237*e9a128d8SLei Wen } 1238*e9a128d8SLei Wen #ifdef DEBUG 1239*e9a128d8SLei Wen s->bits_sent += (ulg)len<<3; 1240*e9a128d8SLei Wen #endif 1241*e9a128d8SLei Wen while (len--) { 1242*e9a128d8SLei Wen put_byte(s, *buf++); 1243*e9a128d8SLei Wen } 1244*e9a128d8SLei Wen } 1245