1e9a128d8SLei Wen /* trees.c -- output deflated data using Huffman coding 2e9a128d8SLei Wen * Copyright (C) 1995-2010 Jean-loup Gailly 3e9a128d8SLei Wen * detect_data_type() function provided freely by Cosmin Truta, 2006 4e9a128d8SLei Wen * For conditions of distribution and use, see copyright notice in zlib.h 5e9a128d8SLei Wen */ 6e9a128d8SLei Wen 7e9a128d8SLei Wen /* 8e9a128d8SLei Wen * ALGORITHM 9e9a128d8SLei Wen * 10e9a128d8SLei Wen * The "deflation" process uses several Huffman trees. The more 11e9a128d8SLei Wen * common source values are represented by shorter bit sequences. 12e9a128d8SLei Wen * 13e9a128d8SLei Wen * Each code tree is stored in a compressed form which is itself 14e9a128d8SLei Wen * a Huffman encoding of the lengths of all the code strings (in 15e9a128d8SLei Wen * ascending order by source values). The actual code strings are 16e9a128d8SLei Wen * reconstructed from the lengths in the inflate process, as described 17e9a128d8SLei Wen * in the deflate specification. 18e9a128d8SLei Wen * 19e9a128d8SLei Wen * REFERENCES 20e9a128d8SLei Wen * 21e9a128d8SLei Wen * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification". 22e9a128d8SLei Wen * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc 23e9a128d8SLei Wen * 24e9a128d8SLei Wen * Storer, James A. 25e9a128d8SLei Wen * Data Compression: Methods and Theory, pp. 49-50. 26e9a128d8SLei Wen * Computer Science Press, 1988. ISBN 0-7167-8156-5. 27e9a128d8SLei Wen * 28e9a128d8SLei Wen * Sedgewick, R. 29e9a128d8SLei Wen * Algorithms, p290. 30e9a128d8SLei Wen * Addison-Wesley, 1983. ISBN 0-201-06672-6. 31e9a128d8SLei Wen */ 32e9a128d8SLei Wen 33e9a128d8SLei Wen /* @(#) $Id$ */ 34e9a128d8SLei Wen 35e9a128d8SLei Wen /* #define GEN_TREES_H */ 36e9a128d8SLei Wen 37e9a128d8SLei Wen #include "deflate.h" 38e9a128d8SLei Wen 39e9a128d8SLei Wen #ifdef DEBUG 40e9a128d8SLei Wen # include <ctype.h> 41e9a128d8SLei Wen #endif 42e9a128d8SLei Wen 43e9a128d8SLei Wen /* =========================================================================== 44e9a128d8SLei Wen * Constants 45e9a128d8SLei Wen */ 46e9a128d8SLei Wen 47e9a128d8SLei Wen #define MAX_BL_BITS 7 48e9a128d8SLei Wen /* Bit length codes must not exceed MAX_BL_BITS bits */ 49e9a128d8SLei Wen 50e9a128d8SLei Wen #define END_BLOCK 256 51e9a128d8SLei Wen /* end of block literal code */ 52e9a128d8SLei Wen 53e9a128d8SLei Wen #define REP_3_6 16 54e9a128d8SLei Wen /* repeat previous bit length 3-6 times (2 bits of repeat count) */ 55e9a128d8SLei Wen 56e9a128d8SLei Wen #define REPZ_3_10 17 57e9a128d8SLei Wen /* repeat a zero length 3-10 times (3 bits of repeat count) */ 58e9a128d8SLei Wen 59e9a128d8SLei Wen #define REPZ_11_138 18 60e9a128d8SLei Wen /* repeat a zero length 11-138 times (7 bits of repeat count) */ 61e9a128d8SLei Wen 62e9a128d8SLei Wen local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ 63e9a128d8SLei 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}; 64e9a128d8SLei Wen 65e9a128d8SLei Wen local const int extra_dbits[D_CODES] /* extra bits for each distance code */ 66e9a128d8SLei 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}; 67e9a128d8SLei Wen 68e9a128d8SLei Wen local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */ 69e9a128d8SLei Wen = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; 70e9a128d8SLei Wen 71e9a128d8SLei Wen local const uch bl_order[BL_CODES] 72e9a128d8SLei Wen = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; 73e9a128d8SLei Wen /* The lengths of the bit length codes are sent in order of decreasing 74e9a128d8SLei Wen * probability, to avoid transmitting the lengths for unused bit length codes. 75e9a128d8SLei Wen */ 76e9a128d8SLei Wen 77e9a128d8SLei Wen #define Buf_size (8 * 2*sizeof(char)) 78e9a128d8SLei Wen /* Number of bits used within bi_buf. (bi_buf might be implemented on 79e9a128d8SLei Wen * more than 16 bits on some systems.) 80e9a128d8SLei Wen */ 81e9a128d8SLei Wen 82e9a128d8SLei Wen /* =========================================================================== 83e9a128d8SLei Wen * Local data. These are initialized only once. 84e9a128d8SLei Wen */ 85e9a128d8SLei Wen 86e9a128d8SLei Wen #define DIST_CODE_LEN 512 /* see definition of array dist_code below */ 87e9a128d8SLei Wen 88e9a128d8SLei Wen #if defined(GEN_TREES_H) || !defined(STDC) 89e9a128d8SLei Wen /* non ANSI compilers may not accept trees.h */ 90e9a128d8SLei Wen 91e9a128d8SLei Wen local ct_data static_ltree[L_CODES+2]; 92e9a128d8SLei Wen /* The static literal tree. Since the bit lengths are imposed, there is no 93e9a128d8SLei Wen * need for the L_CODES extra codes used during heap construction. However 94e9a128d8SLei Wen * The codes 286 and 287 are needed to build a canonical tree (see _tr_init 95e9a128d8SLei Wen * below). 96e9a128d8SLei Wen */ 97e9a128d8SLei Wen 98e9a128d8SLei Wen local ct_data static_dtree[D_CODES]; 99e9a128d8SLei Wen /* The static distance tree. (Actually a trivial tree since all codes use 100e9a128d8SLei Wen * 5 bits.) 101e9a128d8SLei Wen */ 102e9a128d8SLei Wen 103e9a128d8SLei Wen uch _dist_code[DIST_CODE_LEN]; 104e9a128d8SLei Wen /* Distance codes. The first 256 values correspond to the distances 105e9a128d8SLei Wen * 3 .. 258, the last 256 values correspond to the top 8 bits of 106e9a128d8SLei Wen * the 15 bit distances. 107e9a128d8SLei Wen */ 108e9a128d8SLei Wen 109e9a128d8SLei Wen uch _length_code[MAX_MATCH-MIN_MATCH+1]; 110e9a128d8SLei Wen /* length code for each normalized match length (0 == MIN_MATCH) */ 111e9a128d8SLei Wen 112e9a128d8SLei Wen local int base_length[LENGTH_CODES]; 113e9a128d8SLei Wen /* First normalized length for each code (0 = MIN_MATCH) */ 114e9a128d8SLei Wen 115e9a128d8SLei Wen local int base_dist[D_CODES]; 116e9a128d8SLei Wen /* First normalized distance for each code (0 = distance of 1) */ 117e9a128d8SLei Wen 118e9a128d8SLei Wen #else 119e9a128d8SLei Wen # include "trees.h" 120e9a128d8SLei Wen #endif /* GEN_TREES_H */ 121e9a128d8SLei Wen 122e9a128d8SLei Wen struct static_tree_desc_s { 123e9a128d8SLei Wen const ct_data *static_tree; /* static tree or NULL */ 124e9a128d8SLei Wen const intf *extra_bits; /* extra bits for each code or NULL */ 125e9a128d8SLei Wen int extra_base; /* base index for extra_bits */ 126e9a128d8SLei Wen int elems; /* max number of elements in the tree */ 127e9a128d8SLei Wen int max_length; /* max bit length for the codes */ 128e9a128d8SLei Wen }; 129e9a128d8SLei Wen 130e9a128d8SLei Wen local static_tree_desc static_l_desc = 131e9a128d8SLei Wen {static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS}; 132e9a128d8SLei Wen 133e9a128d8SLei Wen local static_tree_desc static_d_desc = 134e9a128d8SLei Wen {static_dtree, extra_dbits, 0, D_CODES, MAX_BITS}; 135e9a128d8SLei Wen 136e9a128d8SLei Wen local static_tree_desc static_bl_desc = 137e9a128d8SLei Wen {(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS}; 138e9a128d8SLei Wen 139e9a128d8SLei Wen /* =========================================================================== 140e9a128d8SLei Wen * Local (static) routines in this file. 141e9a128d8SLei Wen */ 142e9a128d8SLei Wen 143e9a128d8SLei Wen local void tr_static_init OF((void)); 144e9a128d8SLei Wen local void init_block OF((deflate_state *s)); 145e9a128d8SLei Wen local void pqdownheap OF((deflate_state *s, ct_data *tree, int k)); 146e9a128d8SLei Wen local void gen_bitlen OF((deflate_state *s, tree_desc *desc)); 147e9a128d8SLei Wen local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count)); 148e9a128d8SLei Wen local void build_tree OF((deflate_state *s, tree_desc *desc)); 149e9a128d8SLei Wen local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code)); 150e9a128d8SLei Wen local void send_tree OF((deflate_state *s, ct_data *tree, int max_code)); 151e9a128d8SLei Wen local int build_bl_tree OF((deflate_state *s)); 152e9a128d8SLei Wen local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes, 153e9a128d8SLei Wen int blcodes)); 154e9a128d8SLei Wen local void compress_block OF((deflate_state *s, ct_data *ltree, 155e9a128d8SLei Wen ct_data *dtree)); 156e9a128d8SLei Wen local int detect_data_type OF((deflate_state *s)); 157e9a128d8SLei Wen local unsigned bi_reverse OF((unsigned value, int length)); 158e9a128d8SLei Wen local void bi_windup OF((deflate_state *s)); 159e9a128d8SLei Wen local void bi_flush OF((deflate_state *s)); 160e9a128d8SLei Wen local void copy_block OF((deflate_state *s, charf *buf, unsigned len, 161e9a128d8SLei Wen int header)); 162e9a128d8SLei Wen 163e9a128d8SLei Wen #ifdef GEN_TREES_H 164e9a128d8SLei Wen local void gen_trees_header OF((void)); 165e9a128d8SLei Wen #endif 166e9a128d8SLei Wen 167e9a128d8SLei Wen #ifndef DEBUG 168e9a128d8SLei Wen # define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len) 169e9a128d8SLei Wen /* Send a code of the given tree. c and tree must not have side effects */ 170e9a128d8SLei Wen 171e9a128d8SLei Wen #else /* DEBUG */ 172e9a128d8SLei Wen # define send_code(s, c, tree) \ 173e9a128d8SLei Wen { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \ 174e9a128d8SLei Wen send_bits(s, tree[c].Code, tree[c].Len); } 175e9a128d8SLei Wen #endif 176e9a128d8SLei Wen 177e9a128d8SLei Wen /* =========================================================================== 178e9a128d8SLei Wen * Output a short LSB first on the stream. 179e9a128d8SLei Wen * IN assertion: there is enough room in pendingBuf. 180e9a128d8SLei Wen */ 181e9a128d8SLei Wen #define put_short(s, w) { \ 182e9a128d8SLei Wen put_byte(s, (uch)((w) & 0xff)); \ 183e9a128d8SLei Wen put_byte(s, (uch)((ush)(w) >> 8)); \ 184e9a128d8SLei Wen } 185e9a128d8SLei Wen 186e9a128d8SLei Wen /* =========================================================================== 187e9a128d8SLei Wen * Send a value on a given number of bits. 188e9a128d8SLei Wen * IN assertion: length <= 16 and value fits in length bits. 189e9a128d8SLei Wen */ 190e9a128d8SLei Wen #ifdef DEBUG 191e9a128d8SLei Wen local void send_bits OF((deflate_state *s, int value, int length)); 192e9a128d8SLei Wen 193e9a128d8SLei Wen local void send_bits(s, value, length) 194e9a128d8SLei Wen deflate_state *s; 195e9a128d8SLei Wen int value; /* value to send */ 196e9a128d8SLei Wen int length; /* number of bits */ 197e9a128d8SLei Wen { 198e9a128d8SLei Wen Tracevv((stderr," l %2d v %4x ", length, value)); 199e9a128d8SLei Wen Assert(length > 0 && length <= 15, "invalid length"); 200e9a128d8SLei Wen s->bits_sent += (ulg)length; 201e9a128d8SLei Wen 202e9a128d8SLei Wen /* If not enough room in bi_buf, use (valid) bits from bi_buf and 203e9a128d8SLei Wen * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid)) 204e9a128d8SLei Wen * unused bits in value. 205e9a128d8SLei Wen */ 206e9a128d8SLei Wen if (s->bi_valid > (int)Buf_size - length) { 207e9a128d8SLei Wen s->bi_buf |= (ush)value << s->bi_valid; 208e9a128d8SLei Wen put_short(s, s->bi_buf); 209e9a128d8SLei Wen s->bi_buf = (ush)value >> (Buf_size - s->bi_valid); 210e9a128d8SLei Wen s->bi_valid += length - Buf_size; 211e9a128d8SLei Wen } else { 212e9a128d8SLei Wen s->bi_buf |= (ush)value << s->bi_valid; 213e9a128d8SLei Wen s->bi_valid += length; 214e9a128d8SLei Wen } 215e9a128d8SLei Wen } 216e9a128d8SLei Wen #else /* !DEBUG */ 217e9a128d8SLei Wen 218e9a128d8SLei Wen #define send_bits(s, value, length) \ 219e9a128d8SLei Wen { int len = length;\ 220e9a128d8SLei Wen if (s->bi_valid > (int)Buf_size - len) {\ 221e9a128d8SLei Wen int val = value;\ 222e9a128d8SLei Wen s->bi_buf |= (ush)val << s->bi_valid;\ 223e9a128d8SLei Wen put_short(s, s->bi_buf);\ 224e9a128d8SLei Wen s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\ 225e9a128d8SLei Wen s->bi_valid += len - Buf_size;\ 226e9a128d8SLei Wen } else {\ 227e9a128d8SLei Wen s->bi_buf |= (ush)(value) << s->bi_valid;\ 228e9a128d8SLei Wen s->bi_valid += len;\ 229e9a128d8SLei Wen }\ 230e9a128d8SLei Wen } 231e9a128d8SLei Wen #endif /* DEBUG */ 232e9a128d8SLei Wen 233e9a128d8SLei Wen 234e9a128d8SLei Wen /* the arguments must not have side effects */ 235e9a128d8SLei Wen 236e9a128d8SLei Wen /* =========================================================================== 237e9a128d8SLei Wen * Initialize the various 'constant' tables. 238e9a128d8SLei Wen */ 239e9a128d8SLei Wen local void tr_static_init() 240e9a128d8SLei Wen { 241e9a128d8SLei Wen #if defined(GEN_TREES_H) || !defined(STDC) 242e9a128d8SLei Wen static int static_init_done = 0; 243e9a128d8SLei Wen int n; /* iterates over tree elements */ 244e9a128d8SLei Wen int bits; /* bit counter */ 245e9a128d8SLei Wen int length; /* length value */ 246e9a128d8SLei Wen int code; /* code value */ 247e9a128d8SLei Wen int dist; /* distance index */ 248e9a128d8SLei Wen ush bl_count[MAX_BITS+1]; 249e9a128d8SLei Wen /* number of codes at each bit length for an optimal tree */ 250e9a128d8SLei Wen 251e9a128d8SLei Wen if (static_init_done) return; 252e9a128d8SLei Wen 253e9a128d8SLei Wen /* For some embedded targets, global variables are not initialized: */ 254e9a128d8SLei Wen #ifdef NO_INIT_GLOBAL_POINTERS 255e9a128d8SLei Wen static_l_desc.static_tree = static_ltree; 256e9a128d8SLei Wen static_l_desc.extra_bits = extra_lbits; 257e9a128d8SLei Wen static_d_desc.static_tree = static_dtree; 258e9a128d8SLei Wen static_d_desc.extra_bits = extra_dbits; 259e9a128d8SLei Wen static_bl_desc.extra_bits = extra_blbits; 260e9a128d8SLei Wen #endif 261e9a128d8SLei Wen 262e9a128d8SLei Wen /* Initialize the mapping length (0..255) -> length code (0..28) */ 263e9a128d8SLei Wen length = 0; 264e9a128d8SLei Wen for (code = 0; code < LENGTH_CODES-1; code++) { 265e9a128d8SLei Wen base_length[code] = length; 266e9a128d8SLei Wen for (n = 0; n < (1<<extra_lbits[code]); n++) { 267e9a128d8SLei Wen _length_code[length++] = (uch)code; 268e9a128d8SLei Wen } 269e9a128d8SLei Wen } 270e9a128d8SLei Wen Assert (length == 256, "tr_static_init: length != 256"); 271e9a128d8SLei Wen /* Note that the length 255 (match length 258) can be represented 272e9a128d8SLei Wen * in two different ways: code 284 + 5 bits or code 285, so we 273e9a128d8SLei Wen * overwrite length_code[255] to use the best encoding: 274e9a128d8SLei Wen */ 275e9a128d8SLei Wen _length_code[length-1] = (uch)code; 276e9a128d8SLei Wen 277e9a128d8SLei Wen /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ 278e9a128d8SLei Wen dist = 0; 279e9a128d8SLei Wen for (code = 0 ; code < 16; code++) { 280e9a128d8SLei Wen base_dist[code] = dist; 281e9a128d8SLei Wen for (n = 0; n < (1<<extra_dbits[code]); n++) { 282e9a128d8SLei Wen _dist_code[dist++] = (uch)code; 283e9a128d8SLei Wen } 284e9a128d8SLei Wen } 285e9a128d8SLei Wen Assert (dist == 256, "tr_static_init: dist != 256"); 286e9a128d8SLei Wen dist >>= 7; /* from now on, all distances are divided by 128 */ 287e9a128d8SLei Wen for ( ; code < D_CODES; code++) { 288e9a128d8SLei Wen base_dist[code] = dist << 7; 289e9a128d8SLei Wen for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { 290e9a128d8SLei Wen _dist_code[256 + dist++] = (uch)code; 291e9a128d8SLei Wen } 292e9a128d8SLei Wen } 293e9a128d8SLei Wen Assert (dist == 256, "tr_static_init: 256+dist != 512"); 294e9a128d8SLei Wen 295e9a128d8SLei Wen /* Construct the codes of the static literal tree */ 296e9a128d8SLei Wen for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; 297e9a128d8SLei Wen n = 0; 298e9a128d8SLei Wen while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; 299e9a128d8SLei Wen while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; 300e9a128d8SLei Wen while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; 301e9a128d8SLei Wen while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; 302e9a128d8SLei Wen /* Codes 286 and 287 do not exist, but we must include them in the 303e9a128d8SLei Wen * tree construction to get a canonical Huffman tree (longest code 304e9a128d8SLei Wen * all ones) 305e9a128d8SLei Wen */ 306e9a128d8SLei Wen gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count); 307e9a128d8SLei Wen 308e9a128d8SLei Wen /* The static distance tree is trivial: */ 309e9a128d8SLei Wen for (n = 0; n < D_CODES; n++) { 310e9a128d8SLei Wen static_dtree[n].Len = 5; 311e9a128d8SLei Wen static_dtree[n].Code = bi_reverse((unsigned)n, 5); 312e9a128d8SLei Wen } 313e9a128d8SLei Wen static_init_done = 1; 314e9a128d8SLei Wen 315e9a128d8SLei Wen # ifdef GEN_TREES_H 316e9a128d8SLei Wen gen_trees_header(); 317e9a128d8SLei Wen # endif 318e9a128d8SLei Wen #endif /* defined(GEN_TREES_H) || !defined(STDC) */ 319e9a128d8SLei Wen } 320e9a128d8SLei Wen 321e9a128d8SLei Wen /* =========================================================================== 322e9a128d8SLei Wen * Genererate the file trees.h describing the static trees. 323e9a128d8SLei Wen */ 324e9a128d8SLei Wen #ifdef GEN_TREES_H 325e9a128d8SLei Wen # ifndef DEBUG 326e9a128d8SLei Wen # include <stdio.h> 327e9a128d8SLei Wen # endif 328e9a128d8SLei Wen 329e9a128d8SLei Wen # define SEPARATOR(i, last, width) \ 330e9a128d8SLei Wen ((i) == (last)? "\n};\n\n" : \ 331e9a128d8SLei Wen ((i) % (width) == (width)-1 ? ",\n" : ", ")) 332e9a128d8SLei Wen 333e9a128d8SLei Wen void gen_trees_header() 334e9a128d8SLei Wen { 335e9a128d8SLei Wen FILE *header = fopen("trees.h", "w"); 336e9a128d8SLei Wen int i; 337e9a128d8SLei Wen 338e9a128d8SLei Wen Assert (header != NULL, "Can't open trees.h"); 339e9a128d8SLei Wen fprintf(header, 340e9a128d8SLei Wen "/* header created automatically with -DGEN_TREES_H */\n\n"); 341e9a128d8SLei Wen 342e9a128d8SLei Wen fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n"); 343e9a128d8SLei Wen for (i = 0; i < L_CODES+2; i++) { 344e9a128d8SLei Wen fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code, 345e9a128d8SLei Wen static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5)); 346e9a128d8SLei Wen } 347e9a128d8SLei Wen 348e9a128d8SLei Wen fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n"); 349e9a128d8SLei Wen for (i = 0; i < D_CODES; i++) { 350e9a128d8SLei Wen fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code, 351e9a128d8SLei Wen static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5)); 352e9a128d8SLei Wen } 353e9a128d8SLei Wen 354e9a128d8SLei Wen fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n"); 355e9a128d8SLei Wen for (i = 0; i < DIST_CODE_LEN; i++) { 356e9a128d8SLei Wen fprintf(header, "%2u%s", _dist_code[i], 357e9a128d8SLei Wen SEPARATOR(i, DIST_CODE_LEN-1, 20)); 358e9a128d8SLei Wen } 359e9a128d8SLei Wen 360e9a128d8SLei Wen fprintf(header, 361e9a128d8SLei Wen "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n"); 362e9a128d8SLei Wen for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) { 363e9a128d8SLei Wen fprintf(header, "%2u%s", _length_code[i], 364e9a128d8SLei Wen SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20)); 365e9a128d8SLei Wen } 366e9a128d8SLei Wen 367e9a128d8SLei Wen fprintf(header, "local const int base_length[LENGTH_CODES] = {\n"); 368e9a128d8SLei Wen for (i = 0; i < LENGTH_CODES; i++) { 369e9a128d8SLei Wen fprintf(header, "%1u%s", base_length[i], 370e9a128d8SLei Wen SEPARATOR(i, LENGTH_CODES-1, 20)); 371e9a128d8SLei Wen } 372e9a128d8SLei Wen 373e9a128d8SLei Wen fprintf(header, "local const int base_dist[D_CODES] = {\n"); 374e9a128d8SLei Wen for (i = 0; i < D_CODES; i++) { 375e9a128d8SLei Wen fprintf(header, "%5u%s", base_dist[i], 376e9a128d8SLei Wen SEPARATOR(i, D_CODES-1, 10)); 377e9a128d8SLei Wen } 378e9a128d8SLei Wen 379e9a128d8SLei Wen fclose(header); 380e9a128d8SLei Wen } 381e9a128d8SLei Wen #endif /* GEN_TREES_H */ 382e9a128d8SLei Wen 383e9a128d8SLei Wen /* =========================================================================== 384e9a128d8SLei Wen * Initialize the tree data structures for a new zlib stream. 385e9a128d8SLei Wen */ 386e9a128d8SLei Wen void ZLIB_INTERNAL _tr_init(s) 387e9a128d8SLei Wen deflate_state *s; 388e9a128d8SLei Wen { 389e9a128d8SLei Wen tr_static_init(); 390e9a128d8SLei Wen 391e9a128d8SLei Wen s->l_desc.dyn_tree = s->dyn_ltree; 392e9a128d8SLei Wen s->l_desc.stat_desc = &static_l_desc; 393e9a128d8SLei Wen 394e9a128d8SLei Wen s->d_desc.dyn_tree = s->dyn_dtree; 395e9a128d8SLei Wen s->d_desc.stat_desc = &static_d_desc; 396e9a128d8SLei Wen 397e9a128d8SLei Wen s->bl_desc.dyn_tree = s->bl_tree; 398e9a128d8SLei Wen s->bl_desc.stat_desc = &static_bl_desc; 399e9a128d8SLei Wen 400e9a128d8SLei Wen s->bi_buf = 0; 401e9a128d8SLei Wen s->bi_valid = 0; 402e9a128d8SLei Wen s->last_eob_len = 8; /* enough lookahead for inflate */ 403e9a128d8SLei Wen #ifdef DEBUG 404e9a128d8SLei Wen s->compressed_len = 0L; 405e9a128d8SLei Wen s->bits_sent = 0L; 406e9a128d8SLei Wen #endif 407e9a128d8SLei Wen 408e9a128d8SLei Wen /* Initialize the first block of the first file: */ 409e9a128d8SLei Wen init_block(s); 410e9a128d8SLei Wen } 411e9a128d8SLei Wen 412e9a128d8SLei Wen /* =========================================================================== 413e9a128d8SLei Wen * Initialize a new block. 414e9a128d8SLei Wen */ 415e9a128d8SLei Wen local void init_block(s) 416e9a128d8SLei Wen deflate_state *s; 417e9a128d8SLei Wen { 418e9a128d8SLei Wen int n; /* iterates over tree elements */ 419e9a128d8SLei Wen 420e9a128d8SLei Wen /* Initialize the trees. */ 421e9a128d8SLei Wen for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0; 422e9a128d8SLei Wen for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0; 423e9a128d8SLei Wen for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0; 424e9a128d8SLei Wen 425e9a128d8SLei Wen s->dyn_ltree[END_BLOCK].Freq = 1; 426e9a128d8SLei Wen s->opt_len = s->static_len = 0L; 427e9a128d8SLei Wen s->last_lit = s->matches = 0; 428e9a128d8SLei Wen } 429e9a128d8SLei Wen 430e9a128d8SLei Wen #define SMALLEST 1 431e9a128d8SLei Wen /* Index within the heap array of least frequent node in the Huffman tree */ 432e9a128d8SLei Wen 433e9a128d8SLei Wen 434e9a128d8SLei Wen /* =========================================================================== 435e9a128d8SLei Wen * Remove the smallest element from the heap and recreate the heap with 436e9a128d8SLei Wen * one less element. Updates heap and heap_len. 437e9a128d8SLei Wen */ 438e9a128d8SLei Wen #define pqremove(s, tree, top) \ 439e9a128d8SLei Wen {\ 440e9a128d8SLei Wen top = s->heap[SMALLEST]; \ 441e9a128d8SLei Wen s->heap[SMALLEST] = s->heap[s->heap_len--]; \ 442e9a128d8SLei Wen pqdownheap(s, tree, SMALLEST); \ 443e9a128d8SLei Wen } 444e9a128d8SLei Wen 445e9a128d8SLei Wen /* =========================================================================== 446e9a128d8SLei Wen * Compares to subtrees, using the tree depth as tie breaker when 447e9a128d8SLei Wen * the subtrees have equal frequency. This minimizes the worst case length. 448e9a128d8SLei Wen */ 449e9a128d8SLei Wen #define smaller(tree, n, m, depth) \ 450e9a128d8SLei Wen (tree[n].Freq < tree[m].Freq || \ 451e9a128d8SLei Wen (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) 452e9a128d8SLei Wen 453e9a128d8SLei Wen /* =========================================================================== 454e9a128d8SLei Wen * Restore the heap property by moving down the tree starting at node k, 455e9a128d8SLei Wen * exchanging a node with the smallest of its two sons if necessary, stopping 456e9a128d8SLei Wen * when the heap property is re-established (each father smaller than its 457e9a128d8SLei Wen * two sons). 458e9a128d8SLei Wen */ 459e9a128d8SLei Wen local void pqdownheap(s, tree, k) 460e9a128d8SLei Wen deflate_state *s; 461e9a128d8SLei Wen ct_data *tree; /* the tree to restore */ 462e9a128d8SLei Wen int k; /* node to move down */ 463e9a128d8SLei Wen { 464e9a128d8SLei Wen int v = s->heap[k]; 465e9a128d8SLei Wen int j = k << 1; /* left son of k */ 466e9a128d8SLei Wen while (j <= s->heap_len) { 467e9a128d8SLei Wen /* Set j to the smallest of the two sons: */ 468e9a128d8SLei Wen if (j < s->heap_len && 469e9a128d8SLei Wen smaller(tree, s->heap[j+1], s->heap[j], s->depth)) { 470e9a128d8SLei Wen j++; 471e9a128d8SLei Wen } 472e9a128d8SLei Wen /* Exit if v is smaller than both sons */ 473e9a128d8SLei Wen if (smaller(tree, v, s->heap[j], s->depth)) break; 474e9a128d8SLei Wen 475e9a128d8SLei Wen /* Exchange v with the smallest son */ 476e9a128d8SLei Wen s->heap[k] = s->heap[j]; k = j; 477e9a128d8SLei Wen 478e9a128d8SLei Wen /* And continue down the tree, setting j to the left son of k */ 479e9a128d8SLei Wen j <<= 1; 480e9a128d8SLei Wen } 481e9a128d8SLei Wen s->heap[k] = v; 482e9a128d8SLei Wen } 483e9a128d8SLei Wen 484e9a128d8SLei Wen /* =========================================================================== 485e9a128d8SLei Wen * Compute the optimal bit lengths for a tree and update the total bit length 486e9a128d8SLei Wen * for the current block. 487e9a128d8SLei Wen * IN assertion: the fields freq and dad are set, heap[heap_max] and 488e9a128d8SLei Wen * above are the tree nodes sorted by increasing frequency. 489e9a128d8SLei Wen * OUT assertions: the field len is set to the optimal bit length, the 490e9a128d8SLei Wen * array bl_count contains the frequencies for each bit length. 491e9a128d8SLei Wen * The length opt_len is updated; static_len is also updated if stree is 492e9a128d8SLei Wen * not null. 493e9a128d8SLei Wen */ 494e9a128d8SLei Wen local void gen_bitlen(s, desc) 495e9a128d8SLei Wen deflate_state *s; 496e9a128d8SLei Wen tree_desc *desc; /* the tree descriptor */ 497e9a128d8SLei Wen { 498e9a128d8SLei Wen ct_data *tree = desc->dyn_tree; 499e9a128d8SLei Wen int max_code = desc->max_code; 500e9a128d8SLei Wen const ct_data *stree = desc->stat_desc->static_tree; 501e9a128d8SLei Wen const intf *extra = desc->stat_desc->extra_bits; 502e9a128d8SLei Wen int base = desc->stat_desc->extra_base; 503e9a128d8SLei Wen int max_length = desc->stat_desc->max_length; 504e9a128d8SLei Wen int h; /* heap index */ 505e9a128d8SLei Wen int n, m; /* iterate over the tree elements */ 506e9a128d8SLei Wen int bits; /* bit length */ 507e9a128d8SLei Wen int xbits; /* extra bits */ 508e9a128d8SLei Wen ush f; /* frequency */ 509e9a128d8SLei Wen int overflow = 0; /* number of elements with bit length too large */ 510e9a128d8SLei Wen 511e9a128d8SLei Wen for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0; 512e9a128d8SLei Wen 513e9a128d8SLei Wen /* In a first pass, compute the optimal bit lengths (which may 514e9a128d8SLei Wen * overflow in the case of the bit length tree). 515e9a128d8SLei Wen */ 516e9a128d8SLei Wen tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */ 517e9a128d8SLei Wen 518e9a128d8SLei Wen for (h = s->heap_max+1; h < HEAP_SIZE; h++) { 519e9a128d8SLei Wen n = s->heap[h]; 520e9a128d8SLei Wen bits = tree[tree[n].Dad].Len + 1; 521e9a128d8SLei Wen if (bits > max_length) bits = max_length, overflow++; 522e9a128d8SLei Wen tree[n].Len = (ush)bits; 523e9a128d8SLei Wen /* We overwrite tree[n].Dad which is no longer needed */ 524e9a128d8SLei Wen 525e9a128d8SLei Wen if (n > max_code) continue; /* not a leaf node */ 526e9a128d8SLei Wen 527e9a128d8SLei Wen s->bl_count[bits]++; 528e9a128d8SLei Wen xbits = 0; 529e9a128d8SLei Wen if (n >= base) xbits = extra[n-base]; 530e9a128d8SLei Wen f = tree[n].Freq; 531e9a128d8SLei Wen s->opt_len += (ulg)f * (bits + xbits); 532e9a128d8SLei Wen if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits); 533e9a128d8SLei Wen } 534e9a128d8SLei Wen if (overflow == 0) return; 535e9a128d8SLei Wen 536e9a128d8SLei Wen Trace((stderr,"\nbit length overflow\n")); 537e9a128d8SLei Wen /* This happens for example on obj2 and pic of the Calgary corpus */ 538e9a128d8SLei Wen 539e9a128d8SLei Wen /* Find the first bit length which could increase: */ 540e9a128d8SLei Wen do { 541e9a128d8SLei Wen bits = max_length-1; 542e9a128d8SLei Wen while (s->bl_count[bits] == 0) bits--; 543e9a128d8SLei Wen s->bl_count[bits]--; /* move one leaf down the tree */ 544e9a128d8SLei Wen s->bl_count[bits+1] += 2; /* move one overflow item as its brother */ 545e9a128d8SLei Wen s->bl_count[max_length]--; 546e9a128d8SLei Wen /* The brother of the overflow item also moves one step up, 547e9a128d8SLei Wen * but this does not affect bl_count[max_length] 548e9a128d8SLei Wen */ 549e9a128d8SLei Wen overflow -= 2; 550e9a128d8SLei Wen } while (overflow > 0); 551e9a128d8SLei Wen 552e9a128d8SLei Wen /* Now recompute all bit lengths, scanning in increasing frequency. 553e9a128d8SLei Wen * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all 554e9a128d8SLei Wen * lengths instead of fixing only the wrong ones. This idea is taken 555e9a128d8SLei Wen * from 'ar' written by Haruhiko Okumura.) 556e9a128d8SLei Wen */ 557e9a128d8SLei Wen for (bits = max_length; bits != 0; bits--) { 558e9a128d8SLei Wen n = s->bl_count[bits]; 559e9a128d8SLei Wen while (n != 0) { 560e9a128d8SLei Wen m = s->heap[--h]; 561e9a128d8SLei Wen if (m > max_code) continue; 562e9a128d8SLei Wen if ((unsigned) tree[m].Len != (unsigned) bits) { 563e9a128d8SLei Wen Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); 564e9a128d8SLei Wen s->opt_len += ((long)bits - (long)tree[m].Len) 565e9a128d8SLei Wen *(long)tree[m].Freq; 566e9a128d8SLei Wen tree[m].Len = (ush)bits; 567e9a128d8SLei Wen } 568e9a128d8SLei Wen n--; 569e9a128d8SLei Wen } 570e9a128d8SLei Wen } 571e9a128d8SLei Wen } 572e9a128d8SLei Wen 573e9a128d8SLei Wen /* =========================================================================== 574e9a128d8SLei Wen * Generate the codes for a given tree and bit counts (which need not be 575e9a128d8SLei Wen * optimal). 576e9a128d8SLei Wen * IN assertion: the array bl_count contains the bit length statistics for 577e9a128d8SLei Wen * the given tree and the field len is set for all tree elements. 578e9a128d8SLei Wen * OUT assertion: the field code is set for all tree elements of non 579e9a128d8SLei Wen * zero code length. 580e9a128d8SLei Wen */ 581e9a128d8SLei Wen local void gen_codes (tree, max_code, bl_count) 582e9a128d8SLei Wen ct_data *tree; /* the tree to decorate */ 583e9a128d8SLei Wen int max_code; /* largest code with non zero frequency */ 584e9a128d8SLei Wen ushf *bl_count; /* number of codes at each bit length */ 585e9a128d8SLei Wen { 586e9a128d8SLei Wen ush next_code[MAX_BITS+1]; /* next code value for each bit length */ 587e9a128d8SLei Wen ush code = 0; /* running code value */ 588e9a128d8SLei Wen int bits; /* bit index */ 589e9a128d8SLei Wen int n; /* code index */ 590e9a128d8SLei Wen 591e9a128d8SLei Wen /* The distribution counts are first used to generate the code values 592e9a128d8SLei Wen * without bit reversal. 593e9a128d8SLei Wen */ 594e9a128d8SLei Wen for (bits = 1; bits <= MAX_BITS; bits++) { 595e9a128d8SLei Wen next_code[bits] = code = (code + bl_count[bits-1]) << 1; 596e9a128d8SLei Wen } 597e9a128d8SLei Wen /* Check that the bit counts in bl_count are consistent. The last code 598e9a128d8SLei Wen * must be all ones. 599e9a128d8SLei Wen */ 600e9a128d8SLei Wen Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, 601e9a128d8SLei Wen "inconsistent bit counts"); 602e9a128d8SLei Wen Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); 603e9a128d8SLei Wen 604e9a128d8SLei Wen for (n = 0; n <= max_code; n++) { 605e9a128d8SLei Wen int len = tree[n].Len; 606e9a128d8SLei Wen if (len == 0) continue; 607e9a128d8SLei Wen /* Now reverse the bits */ 608e9a128d8SLei Wen tree[n].Code = bi_reverse(next_code[len]++, len); 609e9a128d8SLei Wen 610e9a128d8SLei Wen Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", 611e9a128d8SLei Wen n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); 612e9a128d8SLei Wen } 613e9a128d8SLei Wen } 614e9a128d8SLei Wen 615e9a128d8SLei Wen /* =========================================================================== 616e9a128d8SLei Wen * Construct one Huffman tree and assigns the code bit strings and lengths. 617e9a128d8SLei Wen * Update the total bit length for the current block. 618e9a128d8SLei Wen * IN assertion: the field freq is set for all tree elements. 619e9a128d8SLei Wen * OUT assertions: the fields len and code are set to the optimal bit length 620e9a128d8SLei Wen * and corresponding code. The length opt_len is updated; static_len is 621e9a128d8SLei Wen * also updated if stree is not null. The field max_code is set. 622e9a128d8SLei Wen */ 623e9a128d8SLei Wen local void build_tree(s, desc) 624e9a128d8SLei Wen deflate_state *s; 625e9a128d8SLei Wen tree_desc *desc; /* the tree descriptor */ 626e9a128d8SLei Wen { 627e9a128d8SLei Wen ct_data *tree = desc->dyn_tree; 628e9a128d8SLei Wen const ct_data *stree = desc->stat_desc->static_tree; 629e9a128d8SLei Wen int elems = desc->stat_desc->elems; 630e9a128d8SLei Wen int n, m; /* iterate over heap elements */ 631e9a128d8SLei Wen int max_code = -1; /* largest code with non zero frequency */ 632e9a128d8SLei Wen int node; /* new node being created */ 633e9a128d8SLei Wen 634e9a128d8SLei Wen /* Construct the initial heap, with least frequent element in 635e9a128d8SLei Wen * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. 636e9a128d8SLei Wen * heap[0] is not used. 637e9a128d8SLei Wen */ 638e9a128d8SLei Wen s->heap_len = 0, s->heap_max = HEAP_SIZE; 639e9a128d8SLei Wen 640e9a128d8SLei Wen for (n = 0; n < elems; n++) { 641e9a128d8SLei Wen if (tree[n].Freq != 0) { 642e9a128d8SLei Wen s->heap[++(s->heap_len)] = max_code = n; 643e9a128d8SLei Wen s->depth[n] = 0; 644e9a128d8SLei Wen } else { 645e9a128d8SLei Wen tree[n].Len = 0; 646e9a128d8SLei Wen } 647e9a128d8SLei Wen } 648e9a128d8SLei Wen 649e9a128d8SLei Wen /* The pkzip format requires that at least one distance code exists, 650e9a128d8SLei Wen * and that at least one bit should be sent even if there is only one 651e9a128d8SLei Wen * possible code. So to avoid special checks later on we force at least 652e9a128d8SLei Wen * two codes of non zero frequency. 653e9a128d8SLei Wen */ 654e9a128d8SLei Wen while (s->heap_len < 2) { 655e9a128d8SLei Wen node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0); 656e9a128d8SLei Wen tree[node].Freq = 1; 657e9a128d8SLei Wen s->depth[node] = 0; 658e9a128d8SLei Wen s->opt_len--; if (stree) s->static_len -= stree[node].Len; 659e9a128d8SLei Wen /* node is 0 or 1 so it does not have extra bits */ 660e9a128d8SLei Wen } 661e9a128d8SLei Wen desc->max_code = max_code; 662e9a128d8SLei Wen 663e9a128d8SLei Wen /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, 664e9a128d8SLei Wen * establish sub-heaps of increasing lengths: 665e9a128d8SLei Wen */ 666e9a128d8SLei Wen for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n); 667e9a128d8SLei Wen 668e9a128d8SLei Wen /* Construct the Huffman tree by repeatedly combining the least two 669e9a128d8SLei Wen * frequent nodes. 670e9a128d8SLei Wen */ 671e9a128d8SLei Wen node = elems; /* next internal node of the tree */ 672e9a128d8SLei Wen do { 673e9a128d8SLei Wen pqremove(s, tree, n); /* n = node of least frequency */ 674e9a128d8SLei Wen m = s->heap[SMALLEST]; /* m = node of next least frequency */ 675e9a128d8SLei Wen 676e9a128d8SLei Wen s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */ 677e9a128d8SLei Wen s->heap[--(s->heap_max)] = m; 678e9a128d8SLei Wen 679e9a128d8SLei Wen /* Create a new node father of n and m */ 680e9a128d8SLei Wen tree[node].Freq = tree[n].Freq + tree[m].Freq; 681e9a128d8SLei Wen s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ? 682e9a128d8SLei Wen s->depth[n] : s->depth[m]) + 1); 683e9a128d8SLei Wen tree[n].Dad = tree[m].Dad = (ush)node; 684e9a128d8SLei Wen #ifdef DUMP_BL_TREE 685e9a128d8SLei Wen if (tree == s->bl_tree) { 686e9a128d8SLei Wen fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", 687e9a128d8SLei Wen node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); 688e9a128d8SLei Wen } 689e9a128d8SLei Wen #endif 690e9a128d8SLei Wen /* and insert the new node in the heap */ 691e9a128d8SLei Wen s->heap[SMALLEST] = node++; 692e9a128d8SLei Wen pqdownheap(s, tree, SMALLEST); 693e9a128d8SLei Wen 694e9a128d8SLei Wen } while (s->heap_len >= 2); 695e9a128d8SLei Wen 696e9a128d8SLei Wen s->heap[--(s->heap_max)] = s->heap[SMALLEST]; 697e9a128d8SLei Wen 698e9a128d8SLei Wen /* At this point, the fields freq and dad are set. We can now 699e9a128d8SLei Wen * generate the bit lengths. 700e9a128d8SLei Wen */ 701e9a128d8SLei Wen gen_bitlen(s, (tree_desc *)desc); 702e9a128d8SLei Wen 703e9a128d8SLei Wen /* The field len is now set, we can generate the bit codes */ 704e9a128d8SLei Wen gen_codes ((ct_data *)tree, max_code, s->bl_count); 705e9a128d8SLei Wen } 706e9a128d8SLei Wen 707e9a128d8SLei Wen /* =========================================================================== 708e9a128d8SLei Wen * Scan a literal or distance tree to determine the frequencies of the codes 709e9a128d8SLei Wen * in the bit length tree. 710e9a128d8SLei Wen */ 711e9a128d8SLei Wen local void scan_tree (s, tree, max_code) 712e9a128d8SLei Wen deflate_state *s; 713e9a128d8SLei Wen ct_data *tree; /* the tree to be scanned */ 714e9a128d8SLei Wen int max_code; /* and its largest code of non zero frequency */ 715e9a128d8SLei Wen { 716e9a128d8SLei Wen int n; /* iterates over all tree elements */ 717e9a128d8SLei Wen int prevlen = -1; /* last emitted length */ 718e9a128d8SLei Wen int curlen; /* length of current code */ 719e9a128d8SLei Wen int nextlen = tree[0].Len; /* length of next code */ 720e9a128d8SLei Wen int count = 0; /* repeat count of the current code */ 721e9a128d8SLei Wen int max_count = 7; /* max repeat count */ 722e9a128d8SLei Wen int min_count = 4; /* min repeat count */ 723e9a128d8SLei Wen 724e9a128d8SLei Wen if (nextlen == 0) max_count = 138, min_count = 3; 725e9a128d8SLei Wen tree[max_code+1].Len = (ush)0xffff; /* guard */ 726e9a128d8SLei Wen 727e9a128d8SLei Wen for (n = 0; n <= max_code; n++) { 728e9a128d8SLei Wen curlen = nextlen; nextlen = tree[n+1].Len; 729e9a128d8SLei Wen if (++count < max_count && curlen == nextlen) { 730e9a128d8SLei Wen continue; 731e9a128d8SLei Wen } else if (count < min_count) { 732e9a128d8SLei Wen s->bl_tree[curlen].Freq += count; 733e9a128d8SLei Wen } else if (curlen != 0) { 734e9a128d8SLei Wen if (curlen != prevlen) s->bl_tree[curlen].Freq++; 735e9a128d8SLei Wen s->bl_tree[REP_3_6].Freq++; 736e9a128d8SLei Wen } else if (count <= 10) { 737e9a128d8SLei Wen s->bl_tree[REPZ_3_10].Freq++; 738e9a128d8SLei Wen } else { 739e9a128d8SLei Wen s->bl_tree[REPZ_11_138].Freq++; 740e9a128d8SLei Wen } 741e9a128d8SLei Wen count = 0; prevlen = curlen; 742e9a128d8SLei Wen if (nextlen == 0) { 743e9a128d8SLei Wen max_count = 138, min_count = 3; 744e9a128d8SLei Wen } else if (curlen == nextlen) { 745e9a128d8SLei Wen max_count = 6, min_count = 3; 746e9a128d8SLei Wen } else { 747e9a128d8SLei Wen max_count = 7, min_count = 4; 748e9a128d8SLei Wen } 749e9a128d8SLei Wen } 750e9a128d8SLei Wen } 751e9a128d8SLei Wen 752e9a128d8SLei Wen /* =========================================================================== 753e9a128d8SLei Wen * Send a literal or distance tree in compressed form, using the codes in 754e9a128d8SLei Wen * bl_tree. 755e9a128d8SLei Wen */ 756e9a128d8SLei Wen local void send_tree (s, tree, max_code) 757e9a128d8SLei Wen deflate_state *s; 758e9a128d8SLei Wen ct_data *tree; /* the tree to be scanned */ 759e9a128d8SLei Wen int max_code; /* and its largest code of non zero frequency */ 760e9a128d8SLei Wen { 761e9a128d8SLei Wen int n; /* iterates over all tree elements */ 762e9a128d8SLei Wen int prevlen = -1; /* last emitted length */ 763e9a128d8SLei Wen int curlen; /* length of current code */ 764e9a128d8SLei Wen int nextlen = tree[0].Len; /* length of next code */ 765e9a128d8SLei Wen int count = 0; /* repeat count of the current code */ 766e9a128d8SLei Wen int max_count = 7; /* max repeat count */ 767e9a128d8SLei Wen int min_count = 4; /* min repeat count */ 768e9a128d8SLei Wen 769e9a128d8SLei Wen /* tree[max_code+1].Len = -1; */ /* guard already set */ 770e9a128d8SLei Wen if (nextlen == 0) max_count = 138, min_count = 3; 771e9a128d8SLei Wen 772e9a128d8SLei Wen for (n = 0; n <= max_code; n++) { 773e9a128d8SLei Wen curlen = nextlen; nextlen = tree[n+1].Len; 774e9a128d8SLei Wen if (++count < max_count && curlen == nextlen) { 775e9a128d8SLei Wen continue; 776e9a128d8SLei Wen } else if (count < min_count) { 777e9a128d8SLei Wen do { send_code(s, curlen, s->bl_tree); } while (--count != 0); 778e9a128d8SLei Wen 779e9a128d8SLei Wen } else if (curlen != 0) { 780e9a128d8SLei Wen if (curlen != prevlen) { 781e9a128d8SLei Wen send_code(s, curlen, s->bl_tree); count--; 782e9a128d8SLei Wen } 783e9a128d8SLei Wen Assert(count >= 3 && count <= 6, " 3_6?"); 784e9a128d8SLei Wen send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2); 785e9a128d8SLei Wen 786e9a128d8SLei Wen } else if (count <= 10) { 787e9a128d8SLei Wen send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3); 788e9a128d8SLei Wen 789e9a128d8SLei Wen } else { 790e9a128d8SLei Wen send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7); 791e9a128d8SLei Wen } 792e9a128d8SLei Wen count = 0; prevlen = curlen; 793e9a128d8SLei Wen if (nextlen == 0) { 794e9a128d8SLei Wen max_count = 138, min_count = 3; 795e9a128d8SLei Wen } else if (curlen == nextlen) { 796e9a128d8SLei Wen max_count = 6, min_count = 3; 797e9a128d8SLei Wen } else { 798e9a128d8SLei Wen max_count = 7, min_count = 4; 799e9a128d8SLei Wen } 800e9a128d8SLei Wen } 801e9a128d8SLei Wen } 802e9a128d8SLei Wen 803e9a128d8SLei Wen /* =========================================================================== 804e9a128d8SLei Wen * Construct the Huffman tree for the bit lengths and return the index in 805e9a128d8SLei Wen * bl_order of the last bit length code to send. 806e9a128d8SLei Wen */ 807e9a128d8SLei Wen local int build_bl_tree(s) 808e9a128d8SLei Wen deflate_state *s; 809e9a128d8SLei Wen { 810e9a128d8SLei Wen int max_blindex; /* index of last bit length code of non zero freq */ 811e9a128d8SLei Wen 812e9a128d8SLei Wen /* Determine the bit length frequencies for literal and distance trees */ 813e9a128d8SLei Wen scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code); 814e9a128d8SLei Wen scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code); 815e9a128d8SLei Wen 816e9a128d8SLei Wen /* Build the bit length tree: */ 817e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->bl_desc))); 818e9a128d8SLei Wen /* opt_len now includes the length of the tree representations, except 819e9a128d8SLei Wen * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. 820e9a128d8SLei Wen */ 821e9a128d8SLei Wen 822e9a128d8SLei Wen /* Determine the number of bit length codes to send. The pkzip format 823e9a128d8SLei Wen * requires that at least 4 bit length codes be sent. (appnote.txt says 824e9a128d8SLei Wen * 3 but the actual value used is 4.) 825e9a128d8SLei Wen */ 826e9a128d8SLei Wen for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { 827e9a128d8SLei Wen if (s->bl_tree[bl_order[max_blindex]].Len != 0) break; 828e9a128d8SLei Wen } 829e9a128d8SLei Wen /* Update opt_len to include the bit length tree and counts */ 830e9a128d8SLei Wen s->opt_len += 3*(max_blindex+1) + 5+5+4; 831e9a128d8SLei Wen Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", 832e9a128d8SLei Wen s->opt_len, s->static_len)); 833e9a128d8SLei Wen 834e9a128d8SLei Wen return max_blindex; 835e9a128d8SLei Wen } 836e9a128d8SLei Wen 837e9a128d8SLei Wen /* =========================================================================== 838e9a128d8SLei Wen * Send the header for a block using dynamic Huffman trees: the counts, the 839e9a128d8SLei Wen * lengths of the bit length codes, the literal tree and the distance tree. 840e9a128d8SLei Wen * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. 841e9a128d8SLei Wen */ 842e9a128d8SLei Wen local void send_all_trees(s, lcodes, dcodes, blcodes) 843e9a128d8SLei Wen deflate_state *s; 844e9a128d8SLei Wen int lcodes, dcodes, blcodes; /* number of codes for each tree */ 845e9a128d8SLei Wen { 846e9a128d8SLei Wen int rank; /* index in bl_order */ 847e9a128d8SLei Wen 848e9a128d8SLei Wen Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); 849e9a128d8SLei Wen Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, 850e9a128d8SLei Wen "too many codes"); 851e9a128d8SLei Wen Tracev((stderr, "\nbl counts: ")); 852e9a128d8SLei Wen send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */ 853e9a128d8SLei Wen send_bits(s, dcodes-1, 5); 854e9a128d8SLei Wen send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */ 855e9a128d8SLei Wen for (rank = 0; rank < blcodes; rank++) { 856e9a128d8SLei Wen Tracev((stderr, "\nbl code %2d ", bl_order[rank])); 857e9a128d8SLei Wen send_bits(s, s->bl_tree[bl_order[rank]].Len, 3); 858e9a128d8SLei Wen } 859e9a128d8SLei Wen Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent)); 860e9a128d8SLei Wen 861e9a128d8SLei Wen send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */ 862e9a128d8SLei Wen Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent)); 863e9a128d8SLei Wen 864e9a128d8SLei Wen send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */ 865e9a128d8SLei Wen Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent)); 866e9a128d8SLei Wen } 867e9a128d8SLei Wen 868e9a128d8SLei Wen /* =========================================================================== 869e9a128d8SLei Wen * Send a stored block 870e9a128d8SLei Wen */ 871e9a128d8SLei Wen void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last) 872e9a128d8SLei Wen deflate_state *s; 873e9a128d8SLei Wen charf *buf; /* input block */ 874e9a128d8SLei Wen ulg stored_len; /* length of input block */ 875e9a128d8SLei Wen int last; /* one if this is the last block for a file */ 876e9a128d8SLei Wen { 877e9a128d8SLei Wen send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */ 878e9a128d8SLei Wen #ifdef DEBUG 879e9a128d8SLei Wen s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L; 880e9a128d8SLei Wen s->compressed_len += (stored_len + 4) << 3; 881e9a128d8SLei Wen #endif 882e9a128d8SLei Wen copy_block(s, buf, (unsigned)stored_len, 1); /* with header */ 883e9a128d8SLei Wen } 884e9a128d8SLei Wen 885e9a128d8SLei Wen /* =========================================================================== 886e9a128d8SLei Wen * Send one empty static block to give enough lookahead for inflate. 887e9a128d8SLei Wen * This takes 10 bits, of which 7 may remain in the bit buffer. 888e9a128d8SLei Wen * The current inflate code requires 9 bits of lookahead. If the 889e9a128d8SLei Wen * last two codes for the previous block (real code plus EOB) were coded 890e9a128d8SLei Wen * on 5 bits or less, inflate may have only 5+3 bits of lookahead to decode 891e9a128d8SLei Wen * the last real code. In this case we send two empty static blocks instead 892e9a128d8SLei Wen * of one. (There are no problems if the previous block is stored or fixed.) 893e9a128d8SLei Wen * To simplify the code, we assume the worst case of last real code encoded 894e9a128d8SLei Wen * on one bit only. 895e9a128d8SLei Wen */ 896e9a128d8SLei Wen void ZLIB_INTERNAL _tr_align(s) 897e9a128d8SLei Wen deflate_state *s; 898e9a128d8SLei Wen { 899e9a128d8SLei Wen send_bits(s, STATIC_TREES<<1, 3); 900e9a128d8SLei Wen send_code(s, END_BLOCK, static_ltree); 901e9a128d8SLei Wen #ifdef DEBUG 902e9a128d8SLei Wen s->compressed_len += 10L; /* 3 for block type, 7 for EOB */ 903e9a128d8SLei Wen #endif 904e9a128d8SLei Wen bi_flush(s); 905e9a128d8SLei Wen /* Of the 10 bits for the empty block, we have already sent 906e9a128d8SLei Wen * (10 - bi_valid) bits. The lookahead for the last real code (before 907e9a128d8SLei Wen * the EOB of the previous block) was thus at least one plus the length 908e9a128d8SLei Wen * of the EOB plus what we have just sent of the empty static block. 909e9a128d8SLei Wen */ 910e9a128d8SLei Wen if (1 + s->last_eob_len + 10 - s->bi_valid < 9) { 911e9a128d8SLei Wen send_bits(s, STATIC_TREES<<1, 3); 912e9a128d8SLei Wen send_code(s, END_BLOCK, static_ltree); 913e9a128d8SLei Wen #ifdef DEBUG 914e9a128d8SLei Wen s->compressed_len += 10L; 915e9a128d8SLei Wen #endif 916e9a128d8SLei Wen bi_flush(s); 917e9a128d8SLei Wen } 918e9a128d8SLei Wen s->last_eob_len = 7; 919e9a128d8SLei Wen } 920e9a128d8SLei Wen 921e9a128d8SLei Wen /* =========================================================================== 922e9a128d8SLei Wen * Determine the best encoding for the current block: dynamic trees, static 923e9a128d8SLei Wen * trees or store, and output the encoded block to the zip file. 924e9a128d8SLei Wen */ 925e9a128d8SLei Wen void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last) 926e9a128d8SLei Wen deflate_state *s; 927e9a128d8SLei Wen charf *buf; /* input block, or NULL if too old */ 928e9a128d8SLei Wen ulg stored_len; /* length of input block */ 929e9a128d8SLei Wen int last; /* one if this is the last block for a file */ 930e9a128d8SLei Wen { 931e9a128d8SLei Wen ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ 932e9a128d8SLei Wen int max_blindex = 0; /* index of last bit length code of non zero freq */ 933e9a128d8SLei Wen 934e9a128d8SLei Wen /* Build the Huffman trees unless a stored block is forced */ 935e9a128d8SLei Wen if (s->level > 0) { 936e9a128d8SLei Wen 937e9a128d8SLei Wen /* Check if the file is binary or text */ 938e9a128d8SLei Wen if (s->strm->data_type == Z_UNKNOWN) 939e9a128d8SLei Wen s->strm->data_type = detect_data_type(s); 940e9a128d8SLei Wen 941e9a128d8SLei Wen /* Construct the literal and distance trees */ 942e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->l_desc))); 943e9a128d8SLei Wen Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len, 944e9a128d8SLei Wen s->static_len)); 945e9a128d8SLei Wen 946e9a128d8SLei Wen build_tree(s, (tree_desc *)(&(s->d_desc))); 947e9a128d8SLei Wen Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len, 948e9a128d8SLei Wen s->static_len)); 949e9a128d8SLei Wen /* At this point, opt_len and static_len are the total bit lengths of 950e9a128d8SLei Wen * the compressed block data, excluding the tree representations. 951e9a128d8SLei Wen */ 952e9a128d8SLei Wen 953e9a128d8SLei Wen /* Build the bit length tree for the above two trees, and get the index 954e9a128d8SLei Wen * in bl_order of the last bit length code to send. 955e9a128d8SLei Wen */ 956e9a128d8SLei Wen max_blindex = build_bl_tree(s); 957e9a128d8SLei Wen 958e9a128d8SLei Wen /* Determine the best encoding. Compute the block lengths in bytes. */ 959e9a128d8SLei Wen opt_lenb = (s->opt_len+3+7)>>3; 960e9a128d8SLei Wen static_lenb = (s->static_len+3+7)>>3; 961e9a128d8SLei Wen 962e9a128d8SLei Wen Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ", 963e9a128d8SLei Wen opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len, 964e9a128d8SLei Wen s->last_lit)); 965e9a128d8SLei Wen 966e9a128d8SLei Wen if (static_lenb <= opt_lenb) opt_lenb = static_lenb; 967e9a128d8SLei Wen 968e9a128d8SLei Wen } else { 969e9a128d8SLei Wen Assert(buf != (char*)0, "lost buf"); 970e9a128d8SLei Wen opt_lenb = static_lenb = stored_len + 5; /* force a stored block */ 971e9a128d8SLei Wen } 972e9a128d8SLei Wen 973e9a128d8SLei Wen #ifdef FORCE_STORED 974e9a128d8SLei Wen if (buf != (char*)0) { /* force stored block */ 975e9a128d8SLei Wen #else 976e9a128d8SLei Wen if (stored_len+4 <= opt_lenb && buf != (char*)0) { 977e9a128d8SLei Wen /* 4: two words for the lengths */ 978e9a128d8SLei Wen #endif 979e9a128d8SLei Wen /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. 980e9a128d8SLei Wen * Otherwise we can't have processed more than WSIZE input bytes since 981e9a128d8SLei Wen * the last block flush, because compression would have been 982e9a128d8SLei Wen * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to 983e9a128d8SLei Wen * transform a block into a stored block. 984e9a128d8SLei Wen */ 985e9a128d8SLei Wen _tr_stored_block(s, buf, stored_len, last); 986e9a128d8SLei Wen 987e9a128d8SLei Wen #ifdef FORCE_STATIC 988e9a128d8SLei Wen } else if (static_lenb >= 0) { /* force static trees */ 989e9a128d8SLei Wen #else 990e9a128d8SLei Wen } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) { 991e9a128d8SLei Wen #endif 992e9a128d8SLei Wen send_bits(s, (STATIC_TREES<<1)+last, 3); 993e9a128d8SLei Wen compress_block(s, (ct_data *)static_ltree, (ct_data *)static_dtree); 994e9a128d8SLei Wen #ifdef DEBUG 995e9a128d8SLei Wen s->compressed_len += 3 + s->static_len; 996e9a128d8SLei Wen #endif 997e9a128d8SLei Wen } else { 998e9a128d8SLei Wen send_bits(s, (DYN_TREES<<1)+last, 3); 999e9a128d8SLei Wen send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1, 1000e9a128d8SLei Wen max_blindex+1); 1001e9a128d8SLei Wen compress_block(s, (ct_data *)s->dyn_ltree, (ct_data *)s->dyn_dtree); 1002e9a128d8SLei Wen #ifdef DEBUG 1003e9a128d8SLei Wen s->compressed_len += 3 + s->opt_len; 1004e9a128d8SLei Wen #endif 1005e9a128d8SLei Wen } 1006e9a128d8SLei Wen Assert (s->compressed_len == s->bits_sent, "bad compressed size"); 1007e9a128d8SLei Wen /* The above check is made mod 2^32, for files larger than 512 MB 1008e9a128d8SLei Wen * and uLong implemented on 32 bits. 1009e9a128d8SLei Wen */ 1010e9a128d8SLei Wen init_block(s); 1011e9a128d8SLei Wen 1012e9a128d8SLei Wen if (last) { 1013e9a128d8SLei Wen bi_windup(s); 1014e9a128d8SLei Wen #ifdef DEBUG 1015e9a128d8SLei Wen s->compressed_len += 7; /* align on byte boundary */ 1016e9a128d8SLei Wen #endif 1017e9a128d8SLei Wen } 1018e9a128d8SLei Wen Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3, 1019e9a128d8SLei Wen s->compressed_len-7*last)); 1020e9a128d8SLei Wen } 1021e9a128d8SLei Wen 1022e9a128d8SLei Wen /* =========================================================================== 1023e9a128d8SLei Wen * Save the match info and tally the frequency counts. Return true if 1024e9a128d8SLei Wen * the current block must be flushed. 1025e9a128d8SLei Wen */ 1026e9a128d8SLei Wen int ZLIB_INTERNAL _tr_tally (s, dist, lc) 1027e9a128d8SLei Wen deflate_state *s; 1028e9a128d8SLei Wen unsigned dist; /* distance of matched string */ 1029e9a128d8SLei Wen unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ 1030e9a128d8SLei Wen { 1031e9a128d8SLei Wen s->d_buf[s->last_lit] = (ush)dist; 1032e9a128d8SLei Wen s->l_buf[s->last_lit++] = (uch)lc; 1033e9a128d8SLei Wen if (dist == 0) { 1034e9a128d8SLei Wen /* lc is the unmatched char */ 1035e9a128d8SLei Wen s->dyn_ltree[lc].Freq++; 1036e9a128d8SLei Wen } else { 1037e9a128d8SLei Wen s->matches++; 1038e9a128d8SLei Wen /* Here, lc is the match length - MIN_MATCH */ 1039e9a128d8SLei Wen dist--; /* dist = match distance - 1 */ 1040e9a128d8SLei Wen Assert((ush)dist < (ush)MAX_DIST(s) && 1041e9a128d8SLei Wen (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && 1042e9a128d8SLei Wen (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match"); 1043e9a128d8SLei Wen 1044e9a128d8SLei Wen s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++; 1045e9a128d8SLei Wen s->dyn_dtree[d_code(dist)].Freq++; 1046e9a128d8SLei Wen } 1047e9a128d8SLei Wen 1048e9a128d8SLei Wen #ifdef TRUNCATE_BLOCK 1049e9a128d8SLei Wen /* Try to guess if it is profitable to stop the current block here */ 1050e9a128d8SLei Wen if ((s->last_lit & 0x1fff) == 0 && s->level > 2) { 1051e9a128d8SLei Wen /* Compute an upper bound for the compressed length */ 1052e9a128d8SLei Wen ulg out_length = (ulg)s->last_lit*8L; 1053e9a128d8SLei Wen ulg in_length = (ulg)((long)s->strstart - s->block_start); 1054e9a128d8SLei Wen int dcode; 1055e9a128d8SLei Wen for (dcode = 0; dcode < D_CODES; dcode++) { 1056e9a128d8SLei Wen out_length += (ulg)s->dyn_dtree[dcode].Freq * 1057e9a128d8SLei Wen (5L+extra_dbits[dcode]); 1058e9a128d8SLei Wen } 1059e9a128d8SLei Wen out_length >>= 3; 1060e9a128d8SLei Wen Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ", 1061e9a128d8SLei Wen s->last_lit, in_length, out_length, 1062e9a128d8SLei Wen 100L - out_length*100L/in_length)); 1063e9a128d8SLei Wen if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1; 1064e9a128d8SLei Wen } 1065e9a128d8SLei Wen #endif 1066e9a128d8SLei Wen return (s->last_lit == s->lit_bufsize-1); 1067e9a128d8SLei Wen /* We avoid equality with lit_bufsize because of wraparound at 64K 1068e9a128d8SLei Wen * on 16 bit machines and because stored blocks are restricted to 1069e9a128d8SLei Wen * 64K-1 bytes. 1070e9a128d8SLei Wen */ 1071e9a128d8SLei Wen } 1072e9a128d8SLei Wen 1073e9a128d8SLei Wen /* =========================================================================== 1074e9a128d8SLei Wen * Send the block data compressed using the given Huffman trees 1075e9a128d8SLei Wen */ 1076e9a128d8SLei Wen local void compress_block(s, ltree, dtree) 1077e9a128d8SLei Wen deflate_state *s; 1078e9a128d8SLei Wen ct_data *ltree; /* literal tree */ 1079e9a128d8SLei Wen ct_data *dtree; /* distance tree */ 1080e9a128d8SLei Wen { 1081e9a128d8SLei Wen unsigned dist; /* distance of matched string */ 1082e9a128d8SLei Wen int lc; /* match length or unmatched char (if dist == 0) */ 1083e9a128d8SLei Wen unsigned lx = 0; /* running index in l_buf */ 1084e9a128d8SLei Wen unsigned code; /* the code to send */ 1085e9a128d8SLei Wen int extra; /* number of extra bits to send */ 1086e9a128d8SLei Wen 1087e9a128d8SLei Wen if (s->last_lit != 0) do { 1088e9a128d8SLei Wen dist = s->d_buf[lx]; 1089e9a128d8SLei Wen lc = s->l_buf[lx++]; 1090e9a128d8SLei Wen if (dist == 0) { 1091e9a128d8SLei Wen send_code(s, lc, ltree); /* send a literal byte */ 1092e9a128d8SLei Wen Tracecv(isgraph(lc), (stderr," '%c' ", lc)); 1093e9a128d8SLei Wen } else { 1094e9a128d8SLei Wen /* Here, lc is the match length - MIN_MATCH */ 1095e9a128d8SLei Wen code = _length_code[lc]; 1096e9a128d8SLei Wen send_code(s, code+LITERALS+1, ltree); /* send the length code */ 1097e9a128d8SLei Wen extra = extra_lbits[code]; 1098e9a128d8SLei Wen if (extra != 0) { 1099e9a128d8SLei Wen lc -= base_length[code]; 1100e9a128d8SLei Wen send_bits(s, lc, extra); /* send the extra length bits */ 1101e9a128d8SLei Wen } 1102e9a128d8SLei Wen dist--; /* dist is now the match distance - 1 */ 1103e9a128d8SLei Wen code = d_code(dist); 1104e9a128d8SLei Wen Assert (code < D_CODES, "bad d_code"); 1105e9a128d8SLei Wen 1106e9a128d8SLei Wen send_code(s, code, dtree); /* send the distance code */ 1107e9a128d8SLei Wen extra = extra_dbits[code]; 1108e9a128d8SLei Wen if (extra != 0) { 1109e9a128d8SLei Wen dist -= base_dist[code]; 1110e9a128d8SLei Wen send_bits(s, dist, extra); /* send the extra distance bits */ 1111e9a128d8SLei Wen } 1112e9a128d8SLei Wen } /* literal or match pair ? */ 1113e9a128d8SLei Wen 1114e9a128d8SLei Wen /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ 1115e9a128d8SLei Wen Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx, 1116e9a128d8SLei Wen "pendingBuf overflow"); 1117e9a128d8SLei Wen 1118e9a128d8SLei Wen } while (lx < s->last_lit); 1119e9a128d8SLei Wen 1120e9a128d8SLei Wen send_code(s, END_BLOCK, ltree); 1121e9a128d8SLei Wen s->last_eob_len = ltree[END_BLOCK].Len; 1122e9a128d8SLei Wen } 1123e9a128d8SLei Wen 1124e9a128d8SLei Wen /* =========================================================================== 1125e9a128d8SLei Wen * Check if the data type is TEXT or BINARY, using the following algorithm: 1126e9a128d8SLei Wen * - TEXT if the two conditions below are satisfied: 1127e9a128d8SLei Wen * a) There are no non-portable control characters belonging to the 1128e9a128d8SLei Wen * "black list" (0..6, 14..25, 28..31). 1129e9a128d8SLei Wen * b) There is at least one printable character belonging to the 1130e9a128d8SLei Wen * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). 1131e9a128d8SLei Wen * - BINARY otherwise. 1132e9a128d8SLei Wen * - The following partially-portable control characters form a 1133e9a128d8SLei Wen * "gray list" that is ignored in this detection algorithm: 1134e9a128d8SLei Wen * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). 1135e9a128d8SLei Wen * IN assertion: the fields Freq of dyn_ltree are set. 1136e9a128d8SLei Wen */ 1137e9a128d8SLei Wen local int detect_data_type(s) 1138e9a128d8SLei Wen deflate_state *s; 1139e9a128d8SLei Wen { 1140e9a128d8SLei Wen /* black_mask is the bit mask of black-listed bytes 1141e9a128d8SLei Wen * set bits 0..6, 14..25, and 28..31 1142e9a128d8SLei Wen * 0xf3ffc07f = binary 11110011111111111100000001111111 1143e9a128d8SLei Wen */ 1144e9a128d8SLei Wen unsigned long black_mask = 0xf3ffc07fUL; 1145e9a128d8SLei Wen int n; 1146e9a128d8SLei Wen 1147e9a128d8SLei Wen /* Check for non-textual ("black-listed") bytes. */ 1148e9a128d8SLei Wen for (n = 0; n <= 31; n++, black_mask >>= 1) 1149e9a128d8SLei Wen if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0)) 1150e9a128d8SLei Wen return Z_BINARY; 1151e9a128d8SLei Wen 1152e9a128d8SLei Wen /* Check for textual ("white-listed") bytes. */ 1153e9a128d8SLei Wen if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0 1154e9a128d8SLei Wen || s->dyn_ltree[13].Freq != 0) 1155e9a128d8SLei Wen return Z_TEXT; 1156e9a128d8SLei Wen for (n = 32; n < LITERALS; n++) 1157e9a128d8SLei Wen if (s->dyn_ltree[n].Freq != 0) 1158e9a128d8SLei Wen return Z_TEXT; 1159e9a128d8SLei Wen 1160e9a128d8SLei Wen /* There are no "black-listed" or "white-listed" bytes: 1161e9a128d8SLei Wen * this stream either is empty or has tolerated ("gray-listed") bytes only. 1162e9a128d8SLei Wen */ 1163e9a128d8SLei Wen return Z_BINARY; 1164e9a128d8SLei Wen } 1165e9a128d8SLei Wen 1166e9a128d8SLei Wen /* =========================================================================== 1167e9a128d8SLei Wen * Reverse the first len bits of a code, using straightforward code (a faster 1168e9a128d8SLei Wen * method would use a table) 1169e9a128d8SLei Wen * IN assertion: 1 <= len <= 15 1170e9a128d8SLei Wen */ 1171*7a32b98dSLei Wen local unsigned bi_reverse(value, len) 1172*7a32b98dSLei Wen unsigned value; /* the value to invert */ 1173e9a128d8SLei Wen int len; /* its bit length */ 1174e9a128d8SLei Wen { 1175e9a128d8SLei Wen register unsigned res = 0; 1176e9a128d8SLei Wen do { 1177*7a32b98dSLei Wen res |= value & 1; 1178*7a32b98dSLei Wen value >>= 1, res <<= 1; 1179e9a128d8SLei Wen } while (--len > 0); 1180e9a128d8SLei Wen return res >> 1; 1181e9a128d8SLei Wen } 1182e9a128d8SLei Wen 1183e9a128d8SLei Wen /* =========================================================================== 1184e9a128d8SLei Wen * Flush the bit buffer, keeping at most 7 bits in it. 1185e9a128d8SLei Wen */ 1186e9a128d8SLei Wen local void bi_flush(s) 1187e9a128d8SLei Wen deflate_state *s; 1188e9a128d8SLei Wen { 1189e9a128d8SLei Wen if (s->bi_valid == 16) { 1190e9a128d8SLei Wen put_short(s, s->bi_buf); 1191e9a128d8SLei Wen s->bi_buf = 0; 1192e9a128d8SLei Wen s->bi_valid = 0; 1193e9a128d8SLei Wen } else if (s->bi_valid >= 8) { 1194e9a128d8SLei Wen put_byte(s, (Byte)s->bi_buf); 1195e9a128d8SLei Wen s->bi_buf >>= 8; 1196e9a128d8SLei Wen s->bi_valid -= 8; 1197e9a128d8SLei Wen } 1198e9a128d8SLei Wen } 1199e9a128d8SLei Wen 1200e9a128d8SLei Wen /* =========================================================================== 1201e9a128d8SLei Wen * Flush the bit buffer and align the output on a byte boundary 1202e9a128d8SLei Wen */ 1203e9a128d8SLei Wen local void bi_windup(s) 1204e9a128d8SLei Wen deflate_state *s; 1205e9a128d8SLei Wen { 1206e9a128d8SLei Wen if (s->bi_valid > 8) { 1207e9a128d8SLei Wen put_short(s, s->bi_buf); 1208e9a128d8SLei Wen } else if (s->bi_valid > 0) { 1209e9a128d8SLei Wen put_byte(s, (Byte)s->bi_buf); 1210e9a128d8SLei Wen } 1211e9a128d8SLei Wen s->bi_buf = 0; 1212e9a128d8SLei Wen s->bi_valid = 0; 1213e9a128d8SLei Wen #ifdef DEBUG 1214e9a128d8SLei Wen s->bits_sent = (s->bits_sent+7) & ~7; 1215e9a128d8SLei Wen #endif 1216e9a128d8SLei Wen } 1217e9a128d8SLei Wen 1218e9a128d8SLei Wen /* =========================================================================== 1219e9a128d8SLei Wen * Copy a stored block, storing first the length and its 1220e9a128d8SLei Wen * one's complement if requested. 1221e9a128d8SLei Wen */ 1222e9a128d8SLei Wen local void copy_block(s, buf, len, header) 1223e9a128d8SLei Wen deflate_state *s; 1224e9a128d8SLei Wen charf *buf; /* the input data */ 1225e9a128d8SLei Wen unsigned len; /* its length */ 1226e9a128d8SLei Wen int header; /* true if block header must be written */ 1227e9a128d8SLei Wen { 1228e9a128d8SLei Wen bi_windup(s); /* align on byte boundary */ 1229e9a128d8SLei Wen s->last_eob_len = 8; /* enough lookahead for inflate */ 1230e9a128d8SLei Wen 1231e9a128d8SLei Wen if (header) { 1232e9a128d8SLei Wen put_short(s, (ush)len); 1233e9a128d8SLei Wen put_short(s, (ush)~len); 1234e9a128d8SLei Wen #ifdef DEBUG 1235e9a128d8SLei Wen s->bits_sent += 2*16; 1236e9a128d8SLei Wen #endif 1237e9a128d8SLei Wen } 1238e9a128d8SLei Wen #ifdef DEBUG 1239e9a128d8SLei Wen s->bits_sent += (ulg)len<<3; 1240e9a128d8SLei Wen #endif 1241e9a128d8SLei Wen while (len--) { 1242e9a128d8SLei Wen put_byte(s, *buf++); 1243e9a128d8SLei Wen } 1244e9a128d8SLei Wen } 1245