1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/modules/zlib/src/trees.c Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,1226 @@
1.4 +/* trees.c -- output deflated data using Huffman coding
1.5 + * Copyright (C) 1995-2012 Jean-loup Gailly
1.6 + * detect_data_type() function provided freely by Cosmin Truta, 2006
1.7 + * For conditions of distribution and use, see copyright notice in zlib.h
1.8 + */
1.9 +
1.10 +/*
1.11 + * ALGORITHM
1.12 + *
1.13 + * The "deflation" process uses several Huffman trees. The more
1.14 + * common source values are represented by shorter bit sequences.
1.15 + *
1.16 + * Each code tree is stored in a compressed form which is itself
1.17 + * a Huffman encoding of the lengths of all the code strings (in
1.18 + * ascending order by source values). The actual code strings are
1.19 + * reconstructed from the lengths in the inflate process, as described
1.20 + * in the deflate specification.
1.21 + *
1.22 + * REFERENCES
1.23 + *
1.24 + * Deutsch, L.P.,"'Deflate' Compressed Data Format Specification".
1.25 + * Available in ftp.uu.net:/pub/archiving/zip/doc/deflate-1.1.doc
1.26 + *
1.27 + * Storer, James A.
1.28 + * Data Compression: Methods and Theory, pp. 49-50.
1.29 + * Computer Science Press, 1988. ISBN 0-7167-8156-5.
1.30 + *
1.31 + * Sedgewick, R.
1.32 + * Algorithms, p290.
1.33 + * Addison-Wesley, 1983. ISBN 0-201-06672-6.
1.34 + */
1.35 +
1.36 +/* @(#) $Id$ */
1.37 +
1.38 +/* #define GEN_TREES_H */
1.39 +
1.40 +#include "deflate.h"
1.41 +
1.42 +#ifdef DEBUG
1.43 +# include <ctype.h>
1.44 +#endif
1.45 +
1.46 +/* ===========================================================================
1.47 + * Constants
1.48 + */
1.49 +
1.50 +#define MAX_BL_BITS 7
1.51 +/* Bit length codes must not exceed MAX_BL_BITS bits */
1.52 +
1.53 +#define END_BLOCK 256
1.54 +/* end of block literal code */
1.55 +
1.56 +#define REP_3_6 16
1.57 +/* repeat previous bit length 3-6 times (2 bits of repeat count) */
1.58 +
1.59 +#define REPZ_3_10 17
1.60 +/* repeat a zero length 3-10 times (3 bits of repeat count) */
1.61 +
1.62 +#define REPZ_11_138 18
1.63 +/* repeat a zero length 11-138 times (7 bits of repeat count) */
1.64 +
1.65 +local const int extra_lbits[LENGTH_CODES] /* extra bits for each length code */
1.66 + = {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};
1.67 +
1.68 +local const int extra_dbits[D_CODES] /* extra bits for each distance code */
1.69 + = {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};
1.70 +
1.71 +local const int extra_blbits[BL_CODES]/* extra bits for each bit length code */
1.72 + = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7};
1.73 +
1.74 +local const uch bl_order[BL_CODES]
1.75 + = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15};
1.76 +/* The lengths of the bit length codes are sent in order of decreasing
1.77 + * probability, to avoid transmitting the lengths for unused bit length codes.
1.78 + */
1.79 +
1.80 +/* ===========================================================================
1.81 + * Local data. These are initialized only once.
1.82 + */
1.83 +
1.84 +#define DIST_CODE_LEN 512 /* see definition of array dist_code below */
1.85 +
1.86 +#if defined(GEN_TREES_H) || !defined(STDC)
1.87 +/* non ANSI compilers may not accept trees.h */
1.88 +
1.89 +local ct_data static_ltree[L_CODES+2];
1.90 +/* The static literal tree. Since the bit lengths are imposed, there is no
1.91 + * need for the L_CODES extra codes used during heap construction. However
1.92 + * The codes 286 and 287 are needed to build a canonical tree (see _tr_init
1.93 + * below).
1.94 + */
1.95 +
1.96 +local ct_data static_dtree[D_CODES];
1.97 +/* The static distance tree. (Actually a trivial tree since all codes use
1.98 + * 5 bits.)
1.99 + */
1.100 +
1.101 +uch _dist_code[DIST_CODE_LEN];
1.102 +/* Distance codes. The first 256 values correspond to the distances
1.103 + * 3 .. 258, the last 256 values correspond to the top 8 bits of
1.104 + * the 15 bit distances.
1.105 + */
1.106 +
1.107 +uch _length_code[MAX_MATCH-MIN_MATCH+1];
1.108 +/* length code for each normalized match length (0 == MIN_MATCH) */
1.109 +
1.110 +local int base_length[LENGTH_CODES];
1.111 +/* First normalized length for each code (0 = MIN_MATCH) */
1.112 +
1.113 +local int base_dist[D_CODES];
1.114 +/* First normalized distance for each code (0 = distance of 1) */
1.115 +
1.116 +#else
1.117 +# include "trees.h"
1.118 +#endif /* GEN_TREES_H */
1.119 +
1.120 +struct static_tree_desc_s {
1.121 + const ct_data *static_tree; /* static tree or NULL */
1.122 + const intf *extra_bits; /* extra bits for each code or NULL */
1.123 + int extra_base; /* base index for extra_bits */
1.124 + int elems; /* max number of elements in the tree */
1.125 + int max_length; /* max bit length for the codes */
1.126 +};
1.127 +
1.128 +local static_tree_desc static_l_desc =
1.129 +{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
1.130 +
1.131 +local static_tree_desc static_d_desc =
1.132 +{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
1.133 +
1.134 +local static_tree_desc static_bl_desc =
1.135 +{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
1.136 +
1.137 +/* ===========================================================================
1.138 + * Local (static) routines in this file.
1.139 + */
1.140 +
1.141 +local void tr_static_init OF((void));
1.142 +local void init_block OF((deflate_state *s));
1.143 +local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
1.144 +local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
1.145 +local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
1.146 +local void build_tree OF((deflate_state *s, tree_desc *desc));
1.147 +local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
1.148 +local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
1.149 +local int build_bl_tree OF((deflate_state *s));
1.150 +local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
1.151 + int blcodes));
1.152 +local void compress_block OF((deflate_state *s, const ct_data *ltree,
1.153 + const ct_data *dtree));
1.154 +local int detect_data_type OF((deflate_state *s));
1.155 +local unsigned bi_reverse OF((unsigned value, int length));
1.156 +local void bi_windup OF((deflate_state *s));
1.157 +local void bi_flush OF((deflate_state *s));
1.158 +local void copy_block OF((deflate_state *s, charf *buf, unsigned len,
1.159 + int header));
1.160 +
1.161 +#ifdef GEN_TREES_H
1.162 +local void gen_trees_header OF((void));
1.163 +#endif
1.164 +
1.165 +#ifndef DEBUG
1.166 +# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
1.167 + /* Send a code of the given tree. c and tree must not have side effects */
1.168 +
1.169 +#else /* DEBUG */
1.170 +# define send_code(s, c, tree) \
1.171 + { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
1.172 + send_bits(s, tree[c].Code, tree[c].Len); }
1.173 +#endif
1.174 +
1.175 +/* ===========================================================================
1.176 + * Output a short LSB first on the stream.
1.177 + * IN assertion: there is enough room in pendingBuf.
1.178 + */
1.179 +#define put_short(s, w) { \
1.180 + put_byte(s, (uch)((w) & 0xff)); \
1.181 + put_byte(s, (uch)((ush)(w) >> 8)); \
1.182 +}
1.183 +
1.184 +/* ===========================================================================
1.185 + * Send a value on a given number of bits.
1.186 + * IN assertion: length <= 16 and value fits in length bits.
1.187 + */
1.188 +#ifdef DEBUG
1.189 +local void send_bits OF((deflate_state *s, int value, int length));
1.190 +
1.191 +local void send_bits(s, value, length)
1.192 + deflate_state *s;
1.193 + int value; /* value to send */
1.194 + int length; /* number of bits */
1.195 +{
1.196 + Tracevv((stderr," l %2d v %4x ", length, value));
1.197 + Assert(length > 0 && length <= 15, "invalid length");
1.198 + s->bits_sent += (ulg)length;
1.199 +
1.200 + /* If not enough room in bi_buf, use (valid) bits from bi_buf and
1.201 + * (16 - bi_valid) bits from value, leaving (width - (16-bi_valid))
1.202 + * unused bits in value.
1.203 + */
1.204 + if (s->bi_valid > (int)Buf_size - length) {
1.205 + s->bi_buf |= (ush)value << s->bi_valid;
1.206 + put_short(s, s->bi_buf);
1.207 + s->bi_buf = (ush)value >> (Buf_size - s->bi_valid);
1.208 + s->bi_valid += length - Buf_size;
1.209 + } else {
1.210 + s->bi_buf |= (ush)value << s->bi_valid;
1.211 + s->bi_valid += length;
1.212 + }
1.213 +}
1.214 +#else /* !DEBUG */
1.215 +
1.216 +#define send_bits(s, value, length) \
1.217 +{ int len = length;\
1.218 + if (s->bi_valid > (int)Buf_size - len) {\
1.219 + int val = value;\
1.220 + s->bi_buf |= (ush)val << s->bi_valid;\
1.221 + put_short(s, s->bi_buf);\
1.222 + s->bi_buf = (ush)val >> (Buf_size - s->bi_valid);\
1.223 + s->bi_valid += len - Buf_size;\
1.224 + } else {\
1.225 + s->bi_buf |= (ush)(value) << s->bi_valid;\
1.226 + s->bi_valid += len;\
1.227 + }\
1.228 +}
1.229 +#endif /* DEBUG */
1.230 +
1.231 +
1.232 +/* the arguments must not have side effects */
1.233 +
1.234 +/* ===========================================================================
1.235 + * Initialize the various 'constant' tables.
1.236 + */
1.237 +local void tr_static_init()
1.238 +{
1.239 +#if defined(GEN_TREES_H) || !defined(STDC)
1.240 + static int static_init_done = 0;
1.241 + int n; /* iterates over tree elements */
1.242 + int bits; /* bit counter */
1.243 + int length; /* length value */
1.244 + int code; /* code value */
1.245 + int dist; /* distance index */
1.246 + ush bl_count[MAX_BITS+1];
1.247 + /* number of codes at each bit length for an optimal tree */
1.248 +
1.249 + if (static_init_done) return;
1.250 +
1.251 + /* For some embedded targets, global variables are not initialized: */
1.252 +#ifdef NO_INIT_GLOBAL_POINTERS
1.253 + static_l_desc.static_tree = static_ltree;
1.254 + static_l_desc.extra_bits = extra_lbits;
1.255 + static_d_desc.static_tree = static_dtree;
1.256 + static_d_desc.extra_bits = extra_dbits;
1.257 + static_bl_desc.extra_bits = extra_blbits;
1.258 +#endif
1.259 +
1.260 + /* Initialize the mapping length (0..255) -> length code (0..28) */
1.261 + length = 0;
1.262 + for (code = 0; code < LENGTH_CODES-1; code++) {
1.263 + base_length[code] = length;
1.264 + for (n = 0; n < (1<<extra_lbits[code]); n++) {
1.265 + _length_code[length++] = (uch)code;
1.266 + }
1.267 + }
1.268 + Assert (length == 256, "tr_static_init: length != 256");
1.269 + /* Note that the length 255 (match length 258) can be represented
1.270 + * in two different ways: code 284 + 5 bits or code 285, so we
1.271 + * overwrite length_code[255] to use the best encoding:
1.272 + */
1.273 + _length_code[length-1] = (uch)code;
1.274 +
1.275 + /* Initialize the mapping dist (0..32K) -> dist code (0..29) */
1.276 + dist = 0;
1.277 + for (code = 0 ; code < 16; code++) {
1.278 + base_dist[code] = dist;
1.279 + for (n = 0; n < (1<<extra_dbits[code]); n++) {
1.280 + _dist_code[dist++] = (uch)code;
1.281 + }
1.282 + }
1.283 + Assert (dist == 256, "tr_static_init: dist != 256");
1.284 + dist >>= 7; /* from now on, all distances are divided by 128 */
1.285 + for ( ; code < D_CODES; code++) {
1.286 + base_dist[code] = dist << 7;
1.287 + for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) {
1.288 + _dist_code[256 + dist++] = (uch)code;
1.289 + }
1.290 + }
1.291 + Assert (dist == 256, "tr_static_init: 256+dist != 512");
1.292 +
1.293 + /* Construct the codes of the static literal tree */
1.294 + for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0;
1.295 + n = 0;
1.296 + while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++;
1.297 + while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++;
1.298 + while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++;
1.299 + while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++;
1.300 + /* Codes 286 and 287 do not exist, but we must include them in the
1.301 + * tree construction to get a canonical Huffman tree (longest code
1.302 + * all ones)
1.303 + */
1.304 + gen_codes((ct_data *)static_ltree, L_CODES+1, bl_count);
1.305 +
1.306 + /* The static distance tree is trivial: */
1.307 + for (n = 0; n < D_CODES; n++) {
1.308 + static_dtree[n].Len = 5;
1.309 + static_dtree[n].Code = bi_reverse((unsigned)n, 5);
1.310 + }
1.311 + static_init_done = 1;
1.312 +
1.313 +# ifdef GEN_TREES_H
1.314 + gen_trees_header();
1.315 +# endif
1.316 +#endif /* defined(GEN_TREES_H) || !defined(STDC) */
1.317 +}
1.318 +
1.319 +/* ===========================================================================
1.320 + * Genererate the file trees.h describing the static trees.
1.321 + */
1.322 +#ifdef GEN_TREES_H
1.323 +# ifndef DEBUG
1.324 +# include <stdio.h>
1.325 +# endif
1.326 +
1.327 +# define SEPARATOR(i, last, width) \
1.328 + ((i) == (last)? "\n};\n\n" : \
1.329 + ((i) % (width) == (width)-1 ? ",\n" : ", "))
1.330 +
1.331 +void gen_trees_header()
1.332 +{
1.333 + FILE *header = fopen("trees.h", "w");
1.334 + int i;
1.335 +
1.336 + Assert (header != NULL, "Can't open trees.h");
1.337 + fprintf(header,
1.338 + "/* header created automatically with -DGEN_TREES_H */\n\n");
1.339 +
1.340 + fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");
1.341 + for (i = 0; i < L_CODES+2; i++) {
1.342 + fprintf(header, "{{%3u},{%3u}}%s", static_ltree[i].Code,
1.343 + static_ltree[i].Len, SEPARATOR(i, L_CODES+1, 5));
1.344 + }
1.345 +
1.346 + fprintf(header, "local const ct_data static_dtree[D_CODES] = {\n");
1.347 + for (i = 0; i < D_CODES; i++) {
1.348 + fprintf(header, "{{%2u},{%2u}}%s", static_dtree[i].Code,
1.349 + static_dtree[i].Len, SEPARATOR(i, D_CODES-1, 5));
1.350 + }
1.351 +
1.352 + fprintf(header, "const uch ZLIB_INTERNAL _dist_code[DIST_CODE_LEN] = {\n");
1.353 + for (i = 0; i < DIST_CODE_LEN; i++) {
1.354 + fprintf(header, "%2u%s", _dist_code[i],
1.355 + SEPARATOR(i, DIST_CODE_LEN-1, 20));
1.356 + }
1.357 +
1.358 + fprintf(header,
1.359 + "const uch ZLIB_INTERNAL _length_code[MAX_MATCH-MIN_MATCH+1]= {\n");
1.360 + for (i = 0; i < MAX_MATCH-MIN_MATCH+1; i++) {
1.361 + fprintf(header, "%2u%s", _length_code[i],
1.362 + SEPARATOR(i, MAX_MATCH-MIN_MATCH, 20));
1.363 + }
1.364 +
1.365 + fprintf(header, "local const int base_length[LENGTH_CODES] = {\n");
1.366 + for (i = 0; i < LENGTH_CODES; i++) {
1.367 + fprintf(header, "%1u%s", base_length[i],
1.368 + SEPARATOR(i, LENGTH_CODES-1, 20));
1.369 + }
1.370 +
1.371 + fprintf(header, "local const int base_dist[D_CODES] = {\n");
1.372 + for (i = 0; i < D_CODES; i++) {
1.373 + fprintf(header, "%5u%s", base_dist[i],
1.374 + SEPARATOR(i, D_CODES-1, 10));
1.375 + }
1.376 +
1.377 + fclose(header);
1.378 +}
1.379 +#endif /* GEN_TREES_H */
1.380 +
1.381 +/* ===========================================================================
1.382 + * Initialize the tree data structures for a new zlib stream.
1.383 + */
1.384 +void ZLIB_INTERNAL _tr_init(s)
1.385 + deflate_state *s;
1.386 +{
1.387 + tr_static_init();
1.388 +
1.389 + s->l_desc.dyn_tree = s->dyn_ltree;
1.390 + s->l_desc.stat_desc = &static_l_desc;
1.391 +
1.392 + s->d_desc.dyn_tree = s->dyn_dtree;
1.393 + s->d_desc.stat_desc = &static_d_desc;
1.394 +
1.395 + s->bl_desc.dyn_tree = s->bl_tree;
1.396 + s->bl_desc.stat_desc = &static_bl_desc;
1.397 +
1.398 + s->bi_buf = 0;
1.399 + s->bi_valid = 0;
1.400 +#ifdef DEBUG
1.401 + s->compressed_len = 0L;
1.402 + s->bits_sent = 0L;
1.403 +#endif
1.404 +
1.405 + /* Initialize the first block of the first file: */
1.406 + init_block(s);
1.407 +}
1.408 +
1.409 +/* ===========================================================================
1.410 + * Initialize a new block.
1.411 + */
1.412 +local void init_block(s)
1.413 + deflate_state *s;
1.414 +{
1.415 + int n; /* iterates over tree elements */
1.416 +
1.417 + /* Initialize the trees. */
1.418 + for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
1.419 + for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
1.420 + for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
1.421 +
1.422 + s->dyn_ltree[END_BLOCK].Freq = 1;
1.423 + s->opt_len = s->static_len = 0L;
1.424 + s->last_lit = s->matches = 0;
1.425 +}
1.426 +
1.427 +#define SMALLEST 1
1.428 +/* Index within the heap array of least frequent node in the Huffman tree */
1.429 +
1.430 +
1.431 +/* ===========================================================================
1.432 + * Remove the smallest element from the heap and recreate the heap with
1.433 + * one less element. Updates heap and heap_len.
1.434 + */
1.435 +#define pqremove(s, tree, top) \
1.436 +{\
1.437 + top = s->heap[SMALLEST]; \
1.438 + s->heap[SMALLEST] = s->heap[s->heap_len--]; \
1.439 + pqdownheap(s, tree, SMALLEST); \
1.440 +}
1.441 +
1.442 +/* ===========================================================================
1.443 + * Compares to subtrees, using the tree depth as tie breaker when
1.444 + * the subtrees have equal frequency. This minimizes the worst case length.
1.445 + */
1.446 +#define smaller(tree, n, m, depth) \
1.447 + (tree[n].Freq < tree[m].Freq || \
1.448 + (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
1.449 +
1.450 +/* ===========================================================================
1.451 + * Restore the heap property by moving down the tree starting at node k,
1.452 + * exchanging a node with the smallest of its two sons if necessary, stopping
1.453 + * when the heap property is re-established (each father smaller than its
1.454 + * two sons).
1.455 + */
1.456 +local void pqdownheap(s, tree, k)
1.457 + deflate_state *s;
1.458 + ct_data *tree; /* the tree to restore */
1.459 + int k; /* node to move down */
1.460 +{
1.461 + int v = s->heap[k];
1.462 + int j = k << 1; /* left son of k */
1.463 + while (j <= s->heap_len) {
1.464 + /* Set j to the smallest of the two sons: */
1.465 + if (j < s->heap_len &&
1.466 + smaller(tree, s->heap[j+1], s->heap[j], s->depth)) {
1.467 + j++;
1.468 + }
1.469 + /* Exit if v is smaller than both sons */
1.470 + if (smaller(tree, v, s->heap[j], s->depth)) break;
1.471 +
1.472 + /* Exchange v with the smallest son */
1.473 + s->heap[k] = s->heap[j]; k = j;
1.474 +
1.475 + /* And continue down the tree, setting j to the left son of k */
1.476 + j <<= 1;
1.477 + }
1.478 + s->heap[k] = v;
1.479 +}
1.480 +
1.481 +/* ===========================================================================
1.482 + * Compute the optimal bit lengths for a tree and update the total bit length
1.483 + * for the current block.
1.484 + * IN assertion: the fields freq and dad are set, heap[heap_max] and
1.485 + * above are the tree nodes sorted by increasing frequency.
1.486 + * OUT assertions: the field len is set to the optimal bit length, the
1.487 + * array bl_count contains the frequencies for each bit length.
1.488 + * The length opt_len is updated; static_len is also updated if stree is
1.489 + * not null.
1.490 + */
1.491 +local void gen_bitlen(s, desc)
1.492 + deflate_state *s;
1.493 + tree_desc *desc; /* the tree descriptor */
1.494 +{
1.495 + ct_data *tree = desc->dyn_tree;
1.496 + int max_code = desc->max_code;
1.497 + const ct_data *stree = desc->stat_desc->static_tree;
1.498 + const intf *extra = desc->stat_desc->extra_bits;
1.499 + int base = desc->stat_desc->extra_base;
1.500 + int max_length = desc->stat_desc->max_length;
1.501 + int h; /* heap index */
1.502 + int n, m; /* iterate over the tree elements */
1.503 + int bits; /* bit length */
1.504 + int xbits; /* extra bits */
1.505 + ush f; /* frequency */
1.506 + int overflow = 0; /* number of elements with bit length too large */
1.507 +
1.508 + for (bits = 0; bits <= MAX_BITS; bits++) s->bl_count[bits] = 0;
1.509 +
1.510 + /* In a first pass, compute the optimal bit lengths (which may
1.511 + * overflow in the case of the bit length tree).
1.512 + */
1.513 + tree[s->heap[s->heap_max]].Len = 0; /* root of the heap */
1.514 +
1.515 + for (h = s->heap_max+1; h < HEAP_SIZE; h++) {
1.516 + n = s->heap[h];
1.517 + bits = tree[tree[n].Dad].Len + 1;
1.518 + if (bits > max_length) bits = max_length, overflow++;
1.519 + tree[n].Len = (ush)bits;
1.520 + /* We overwrite tree[n].Dad which is no longer needed */
1.521 +
1.522 + if (n > max_code) continue; /* not a leaf node */
1.523 +
1.524 + s->bl_count[bits]++;
1.525 + xbits = 0;
1.526 + if (n >= base) xbits = extra[n-base];
1.527 + f = tree[n].Freq;
1.528 + s->opt_len += (ulg)f * (bits + xbits);
1.529 + if (stree) s->static_len += (ulg)f * (stree[n].Len + xbits);
1.530 + }
1.531 + if (overflow == 0) return;
1.532 +
1.533 + Trace((stderr,"\nbit length overflow\n"));
1.534 + /* This happens for example on obj2 and pic of the Calgary corpus */
1.535 +
1.536 + /* Find the first bit length which could increase: */
1.537 + do {
1.538 + bits = max_length-1;
1.539 + while (s->bl_count[bits] == 0) bits--;
1.540 + s->bl_count[bits]--; /* move one leaf down the tree */
1.541 + s->bl_count[bits+1] += 2; /* move one overflow item as its brother */
1.542 + s->bl_count[max_length]--;
1.543 + /* The brother of the overflow item also moves one step up,
1.544 + * but this does not affect bl_count[max_length]
1.545 + */
1.546 + overflow -= 2;
1.547 + } while (overflow > 0);
1.548 +
1.549 + /* Now recompute all bit lengths, scanning in increasing frequency.
1.550 + * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all
1.551 + * lengths instead of fixing only the wrong ones. This idea is taken
1.552 + * from 'ar' written by Haruhiko Okumura.)
1.553 + */
1.554 + for (bits = max_length; bits != 0; bits--) {
1.555 + n = s->bl_count[bits];
1.556 + while (n != 0) {
1.557 + m = s->heap[--h];
1.558 + if (m > max_code) continue;
1.559 + if ((unsigned) tree[m].Len != (unsigned) bits) {
1.560 + Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits));
1.561 + s->opt_len += ((long)bits - (long)tree[m].Len)
1.562 + *(long)tree[m].Freq;
1.563 + tree[m].Len = (ush)bits;
1.564 + }
1.565 + n--;
1.566 + }
1.567 + }
1.568 +}
1.569 +
1.570 +/* ===========================================================================
1.571 + * Generate the codes for a given tree and bit counts (which need not be
1.572 + * optimal).
1.573 + * IN assertion: the array bl_count contains the bit length statistics for
1.574 + * the given tree and the field len is set for all tree elements.
1.575 + * OUT assertion: the field code is set for all tree elements of non
1.576 + * zero code length.
1.577 + */
1.578 +local void gen_codes (tree, max_code, bl_count)
1.579 + ct_data *tree; /* the tree to decorate */
1.580 + int max_code; /* largest code with non zero frequency */
1.581 + ushf *bl_count; /* number of codes at each bit length */
1.582 +{
1.583 + ush next_code[MAX_BITS+1]; /* next code value for each bit length */
1.584 + ush code = 0; /* running code value */
1.585 + int bits; /* bit index */
1.586 + int n; /* code index */
1.587 +
1.588 + /* The distribution counts are first used to generate the code values
1.589 + * without bit reversal.
1.590 + */
1.591 + for (bits = 1; bits <= MAX_BITS; bits++) {
1.592 + next_code[bits] = code = (code + bl_count[bits-1]) << 1;
1.593 + }
1.594 + /* Check that the bit counts in bl_count are consistent. The last code
1.595 + * must be all ones.
1.596 + */
1.597 + Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1,
1.598 + "inconsistent bit counts");
1.599 + Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
1.600 +
1.601 + for (n = 0; n <= max_code; n++) {
1.602 + int len = tree[n].Len;
1.603 + if (len == 0) continue;
1.604 + /* Now reverse the bits */
1.605 + tree[n].Code = bi_reverse(next_code[len]++, len);
1.606 +
1.607 + Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
1.608 + n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1));
1.609 + }
1.610 +}
1.611 +
1.612 +/* ===========================================================================
1.613 + * Construct one Huffman tree and assigns the code bit strings and lengths.
1.614 + * Update the total bit length for the current block.
1.615 + * IN assertion: the field freq is set for all tree elements.
1.616 + * OUT assertions: the fields len and code are set to the optimal bit length
1.617 + * and corresponding code. The length opt_len is updated; static_len is
1.618 + * also updated if stree is not null. The field max_code is set.
1.619 + */
1.620 +local void build_tree(s, desc)
1.621 + deflate_state *s;
1.622 + tree_desc *desc; /* the tree descriptor */
1.623 +{
1.624 + ct_data *tree = desc->dyn_tree;
1.625 + const ct_data *stree = desc->stat_desc->static_tree;
1.626 + int elems = desc->stat_desc->elems;
1.627 + int n, m; /* iterate over heap elements */
1.628 + int max_code = -1; /* largest code with non zero frequency */
1.629 + int node; /* new node being created */
1.630 +
1.631 + /* Construct the initial heap, with least frequent element in
1.632 + * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1].
1.633 + * heap[0] is not used.
1.634 + */
1.635 + s->heap_len = 0, s->heap_max = HEAP_SIZE;
1.636 +
1.637 + for (n = 0; n < elems; n++) {
1.638 + if (tree[n].Freq != 0) {
1.639 + s->heap[++(s->heap_len)] = max_code = n;
1.640 + s->depth[n] = 0;
1.641 + } else {
1.642 + tree[n].Len = 0;
1.643 + }
1.644 + }
1.645 +
1.646 + /* The pkzip format requires that at least one distance code exists,
1.647 + * and that at least one bit should be sent even if there is only one
1.648 + * possible code. So to avoid special checks later on we force at least
1.649 + * two codes of non zero frequency.
1.650 + */
1.651 + while (s->heap_len < 2) {
1.652 + node = s->heap[++(s->heap_len)] = (max_code < 2 ? ++max_code : 0);
1.653 + tree[node].Freq = 1;
1.654 + s->depth[node] = 0;
1.655 + s->opt_len--; if (stree) s->static_len -= stree[node].Len;
1.656 + /* node is 0 or 1 so it does not have extra bits */
1.657 + }
1.658 + desc->max_code = max_code;
1.659 +
1.660 + /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree,
1.661 + * establish sub-heaps of increasing lengths:
1.662 + */
1.663 + for (n = s->heap_len/2; n >= 1; n--) pqdownheap(s, tree, n);
1.664 +
1.665 + /* Construct the Huffman tree by repeatedly combining the least two
1.666 + * frequent nodes.
1.667 + */
1.668 + node = elems; /* next internal node of the tree */
1.669 + do {
1.670 + pqremove(s, tree, n); /* n = node of least frequency */
1.671 + m = s->heap[SMALLEST]; /* m = node of next least frequency */
1.672 +
1.673 + s->heap[--(s->heap_max)] = n; /* keep the nodes sorted by frequency */
1.674 + s->heap[--(s->heap_max)] = m;
1.675 +
1.676 + /* Create a new node father of n and m */
1.677 + tree[node].Freq = tree[n].Freq + tree[m].Freq;
1.678 + s->depth[node] = (uch)((s->depth[n] >= s->depth[m] ?
1.679 + s->depth[n] : s->depth[m]) + 1);
1.680 + tree[n].Dad = tree[m].Dad = (ush)node;
1.681 +#ifdef DUMP_BL_TREE
1.682 + if (tree == s->bl_tree) {
1.683 + fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)",
1.684 + node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq);
1.685 + }
1.686 +#endif
1.687 + /* and insert the new node in the heap */
1.688 + s->heap[SMALLEST] = node++;
1.689 + pqdownheap(s, tree, SMALLEST);
1.690 +
1.691 + } while (s->heap_len >= 2);
1.692 +
1.693 + s->heap[--(s->heap_max)] = s->heap[SMALLEST];
1.694 +
1.695 + /* At this point, the fields freq and dad are set. We can now
1.696 + * generate the bit lengths.
1.697 + */
1.698 + gen_bitlen(s, (tree_desc *)desc);
1.699 +
1.700 + /* The field len is now set, we can generate the bit codes */
1.701 + gen_codes ((ct_data *)tree, max_code, s->bl_count);
1.702 +}
1.703 +
1.704 +/* ===========================================================================
1.705 + * Scan a literal or distance tree to determine the frequencies of the codes
1.706 + * in the bit length tree.
1.707 + */
1.708 +local void scan_tree (s, tree, max_code)
1.709 + deflate_state *s;
1.710 + ct_data *tree; /* the tree to be scanned */
1.711 + int max_code; /* and its largest code of non zero frequency */
1.712 +{
1.713 + int n; /* iterates over all tree elements */
1.714 + int prevlen = -1; /* last emitted length */
1.715 + int curlen; /* length of current code */
1.716 + int nextlen = tree[0].Len; /* length of next code */
1.717 + int count = 0; /* repeat count of the current code */
1.718 + int max_count = 7; /* max repeat count */
1.719 + int min_count = 4; /* min repeat count */
1.720 +
1.721 + if (nextlen == 0) max_count = 138, min_count = 3;
1.722 + tree[max_code+1].Len = (ush)0xffff; /* guard */
1.723 +
1.724 + for (n = 0; n <= max_code; n++) {
1.725 + curlen = nextlen; nextlen = tree[n+1].Len;
1.726 + if (++count < max_count && curlen == nextlen) {
1.727 + continue;
1.728 + } else if (count < min_count) {
1.729 + s->bl_tree[curlen].Freq += count;
1.730 + } else if (curlen != 0) {
1.731 + if (curlen != prevlen) s->bl_tree[curlen].Freq++;
1.732 + s->bl_tree[REP_3_6].Freq++;
1.733 + } else if (count <= 10) {
1.734 + s->bl_tree[REPZ_3_10].Freq++;
1.735 + } else {
1.736 + s->bl_tree[REPZ_11_138].Freq++;
1.737 + }
1.738 + count = 0; prevlen = curlen;
1.739 + if (nextlen == 0) {
1.740 + max_count = 138, min_count = 3;
1.741 + } else if (curlen == nextlen) {
1.742 + max_count = 6, min_count = 3;
1.743 + } else {
1.744 + max_count = 7, min_count = 4;
1.745 + }
1.746 + }
1.747 +}
1.748 +
1.749 +/* ===========================================================================
1.750 + * Send a literal or distance tree in compressed form, using the codes in
1.751 + * bl_tree.
1.752 + */
1.753 +local void send_tree (s, tree, max_code)
1.754 + deflate_state *s;
1.755 + ct_data *tree; /* the tree to be scanned */
1.756 + int max_code; /* and its largest code of non zero frequency */
1.757 +{
1.758 + int n; /* iterates over all tree elements */
1.759 + int prevlen = -1; /* last emitted length */
1.760 + int curlen; /* length of current code */
1.761 + int nextlen = tree[0].Len; /* length of next code */
1.762 + int count = 0; /* repeat count of the current code */
1.763 + int max_count = 7; /* max repeat count */
1.764 + int min_count = 4; /* min repeat count */
1.765 +
1.766 + /* tree[max_code+1].Len = -1; */ /* guard already set */
1.767 + if (nextlen == 0) max_count = 138, min_count = 3;
1.768 +
1.769 + for (n = 0; n <= max_code; n++) {
1.770 + curlen = nextlen; nextlen = tree[n+1].Len;
1.771 + if (++count < max_count && curlen == nextlen) {
1.772 + continue;
1.773 + } else if (count < min_count) {
1.774 + do { send_code(s, curlen, s->bl_tree); } while (--count != 0);
1.775 +
1.776 + } else if (curlen != 0) {
1.777 + if (curlen != prevlen) {
1.778 + send_code(s, curlen, s->bl_tree); count--;
1.779 + }
1.780 + Assert(count >= 3 && count <= 6, " 3_6?");
1.781 + send_code(s, REP_3_6, s->bl_tree); send_bits(s, count-3, 2);
1.782 +
1.783 + } else if (count <= 10) {
1.784 + send_code(s, REPZ_3_10, s->bl_tree); send_bits(s, count-3, 3);
1.785 +
1.786 + } else {
1.787 + send_code(s, REPZ_11_138, s->bl_tree); send_bits(s, count-11, 7);
1.788 + }
1.789 + count = 0; prevlen = curlen;
1.790 + if (nextlen == 0) {
1.791 + max_count = 138, min_count = 3;
1.792 + } else if (curlen == nextlen) {
1.793 + max_count = 6, min_count = 3;
1.794 + } else {
1.795 + max_count = 7, min_count = 4;
1.796 + }
1.797 + }
1.798 +}
1.799 +
1.800 +/* ===========================================================================
1.801 + * Construct the Huffman tree for the bit lengths and return the index in
1.802 + * bl_order of the last bit length code to send.
1.803 + */
1.804 +local int build_bl_tree(s)
1.805 + deflate_state *s;
1.806 +{
1.807 + int max_blindex; /* index of last bit length code of non zero freq */
1.808 +
1.809 + /* Determine the bit length frequencies for literal and distance trees */
1.810 + scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
1.811 + scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
1.812 +
1.813 + /* Build the bit length tree: */
1.814 + build_tree(s, (tree_desc *)(&(s->bl_desc)));
1.815 + /* opt_len now includes the length of the tree representations, except
1.816 + * the lengths of the bit lengths codes and the 5+5+4 bits for the counts.
1.817 + */
1.818 +
1.819 + /* Determine the number of bit length codes to send. The pkzip format
1.820 + * requires that at least 4 bit length codes be sent. (appnote.txt says
1.821 + * 3 but the actual value used is 4.)
1.822 + */
1.823 + for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) {
1.824 + if (s->bl_tree[bl_order[max_blindex]].Len != 0) break;
1.825 + }
1.826 + /* Update opt_len to include the bit length tree and counts */
1.827 + s->opt_len += 3*(max_blindex+1) + 5+5+4;
1.828 + Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld",
1.829 + s->opt_len, s->static_len));
1.830 +
1.831 + return max_blindex;
1.832 +}
1.833 +
1.834 +/* ===========================================================================
1.835 + * Send the header for a block using dynamic Huffman trees: the counts, the
1.836 + * lengths of the bit length codes, the literal tree and the distance tree.
1.837 + * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
1.838 + */
1.839 +local void send_all_trees(s, lcodes, dcodes, blcodes)
1.840 + deflate_state *s;
1.841 + int lcodes, dcodes, blcodes; /* number of codes for each tree */
1.842 +{
1.843 + int rank; /* index in bl_order */
1.844 +
1.845 + Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
1.846 + Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
1.847 + "too many codes");
1.848 + Tracev((stderr, "\nbl counts: "));
1.849 + send_bits(s, lcodes-257, 5); /* not +255 as stated in appnote.txt */
1.850 + send_bits(s, dcodes-1, 5);
1.851 + send_bits(s, blcodes-4, 4); /* not -3 as stated in appnote.txt */
1.852 + for (rank = 0; rank < blcodes; rank++) {
1.853 + Tracev((stderr, "\nbl code %2d ", bl_order[rank]));
1.854 + send_bits(s, s->bl_tree[bl_order[rank]].Len, 3);
1.855 + }
1.856 + Tracev((stderr, "\nbl tree: sent %ld", s->bits_sent));
1.857 +
1.858 + send_tree(s, (ct_data *)s->dyn_ltree, lcodes-1); /* literal tree */
1.859 + Tracev((stderr, "\nlit tree: sent %ld", s->bits_sent));
1.860 +
1.861 + send_tree(s, (ct_data *)s->dyn_dtree, dcodes-1); /* distance tree */
1.862 + Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
1.863 +}
1.864 +
1.865 +/* ===========================================================================
1.866 + * Send a stored block
1.867 + */
1.868 +void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)
1.869 + deflate_state *s;
1.870 + charf *buf; /* input block */
1.871 + ulg stored_len; /* length of input block */
1.872 + int last; /* one if this is the last block for a file */
1.873 +{
1.874 + send_bits(s, (STORED_BLOCK<<1)+last, 3); /* send block type */
1.875 +#ifdef DEBUG
1.876 + s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
1.877 + s->compressed_len += (stored_len + 4) << 3;
1.878 +#endif
1.879 + copy_block(s, buf, (unsigned)stored_len, 1); /* with header */
1.880 +}
1.881 +
1.882 +/* ===========================================================================
1.883 + * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
1.884 + */
1.885 +void ZLIB_INTERNAL _tr_flush_bits(s)
1.886 + deflate_state *s;
1.887 +{
1.888 + bi_flush(s);
1.889 +}
1.890 +
1.891 +/* ===========================================================================
1.892 + * Send one empty static block to give enough lookahead for inflate.
1.893 + * This takes 10 bits, of which 7 may remain in the bit buffer.
1.894 + */
1.895 +void ZLIB_INTERNAL _tr_align(s)
1.896 + deflate_state *s;
1.897 +{
1.898 + send_bits(s, STATIC_TREES<<1, 3);
1.899 + send_code(s, END_BLOCK, static_ltree);
1.900 +#ifdef DEBUG
1.901 + s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
1.902 +#endif
1.903 + bi_flush(s);
1.904 +}
1.905 +
1.906 +/* ===========================================================================
1.907 + * Determine the best encoding for the current block: dynamic trees, static
1.908 + * trees or store, and output the encoded block to the zip file.
1.909 + */
1.910 +void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
1.911 + deflate_state *s;
1.912 + charf *buf; /* input block, or NULL if too old */
1.913 + ulg stored_len; /* length of input block */
1.914 + int last; /* one if this is the last block for a file */
1.915 +{
1.916 + ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
1.917 + int max_blindex = 0; /* index of last bit length code of non zero freq */
1.918 +
1.919 + /* Build the Huffman trees unless a stored block is forced */
1.920 + if (s->level > 0) {
1.921 +
1.922 + /* Check if the file is binary or text */
1.923 + if (s->strm->data_type == Z_UNKNOWN)
1.924 + s->strm->data_type = detect_data_type(s);
1.925 +
1.926 + /* Construct the literal and distance trees */
1.927 + build_tree(s, (tree_desc *)(&(s->l_desc)));
1.928 + Tracev((stderr, "\nlit data: dyn %ld, stat %ld", s->opt_len,
1.929 + s->static_len));
1.930 +
1.931 + build_tree(s, (tree_desc *)(&(s->d_desc)));
1.932 + Tracev((stderr, "\ndist data: dyn %ld, stat %ld", s->opt_len,
1.933 + s->static_len));
1.934 + /* At this point, opt_len and static_len are the total bit lengths of
1.935 + * the compressed block data, excluding the tree representations.
1.936 + */
1.937 +
1.938 + /* Build the bit length tree for the above two trees, and get the index
1.939 + * in bl_order of the last bit length code to send.
1.940 + */
1.941 + max_blindex = build_bl_tree(s);
1.942 +
1.943 + /* Determine the best encoding. Compute the block lengths in bytes. */
1.944 + opt_lenb = (s->opt_len+3+7)>>3;
1.945 + static_lenb = (s->static_len+3+7)>>3;
1.946 +
1.947 + Tracev((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u ",
1.948 + opt_lenb, s->opt_len, static_lenb, s->static_len, stored_len,
1.949 + s->last_lit));
1.950 +
1.951 + if (static_lenb <= opt_lenb) opt_lenb = static_lenb;
1.952 +
1.953 + } else {
1.954 + Assert(buf != (char*)0, "lost buf");
1.955 + opt_lenb = static_lenb = stored_len + 5; /* force a stored block */
1.956 + }
1.957 +
1.958 +#ifdef FORCE_STORED
1.959 + if (buf != (char*)0) { /* force stored block */
1.960 +#else
1.961 + if (stored_len+4 <= opt_lenb && buf != (char*)0) {
1.962 + /* 4: two words for the lengths */
1.963 +#endif
1.964 + /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE.
1.965 + * Otherwise we can't have processed more than WSIZE input bytes since
1.966 + * the last block flush, because compression would have been
1.967 + * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to
1.968 + * transform a block into a stored block.
1.969 + */
1.970 + _tr_stored_block(s, buf, stored_len, last);
1.971 +
1.972 +#ifdef FORCE_STATIC
1.973 + } else if (static_lenb >= 0) { /* force static trees */
1.974 +#else
1.975 + } else if (s->strategy == Z_FIXED || static_lenb == opt_lenb) {
1.976 +#endif
1.977 + send_bits(s, (STATIC_TREES<<1)+last, 3);
1.978 + compress_block(s, (const ct_data *)static_ltree,
1.979 + (const ct_data *)static_dtree);
1.980 +#ifdef DEBUG
1.981 + s->compressed_len += 3 + s->static_len;
1.982 +#endif
1.983 + } else {
1.984 + send_bits(s, (DYN_TREES<<1)+last, 3);
1.985 + send_all_trees(s, s->l_desc.max_code+1, s->d_desc.max_code+1,
1.986 + max_blindex+1);
1.987 + compress_block(s, (const ct_data *)s->dyn_ltree,
1.988 + (const ct_data *)s->dyn_dtree);
1.989 +#ifdef DEBUG
1.990 + s->compressed_len += 3 + s->opt_len;
1.991 +#endif
1.992 + }
1.993 + Assert (s->compressed_len == s->bits_sent, "bad compressed size");
1.994 + /* The above check is made mod 2^32, for files larger than 512 MB
1.995 + * and uLong implemented on 32 bits.
1.996 + */
1.997 + init_block(s);
1.998 +
1.999 + if (last) {
1.1000 + bi_windup(s);
1.1001 +#ifdef DEBUG
1.1002 + s->compressed_len += 7; /* align on byte boundary */
1.1003 +#endif
1.1004 + }
1.1005 + Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len>>3,
1.1006 + s->compressed_len-7*last));
1.1007 +}
1.1008 +
1.1009 +/* ===========================================================================
1.1010 + * Save the match info and tally the frequency counts. Return true if
1.1011 + * the current block must be flushed.
1.1012 + */
1.1013 +int ZLIB_INTERNAL _tr_tally (s, dist, lc)
1.1014 + deflate_state *s;
1.1015 + unsigned dist; /* distance of matched string */
1.1016 + unsigned lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */
1.1017 +{
1.1018 + s->d_buf[s->last_lit] = (ush)dist;
1.1019 + s->l_buf[s->last_lit++] = (uch)lc;
1.1020 + if (dist == 0) {
1.1021 + /* lc is the unmatched char */
1.1022 + s->dyn_ltree[lc].Freq++;
1.1023 + } else {
1.1024 + s->matches++;
1.1025 + /* Here, lc is the match length - MIN_MATCH */
1.1026 + dist--; /* dist = match distance - 1 */
1.1027 + Assert((ush)dist < (ush)MAX_DIST(s) &&
1.1028 + (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
1.1029 + (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
1.1030 +
1.1031 + s->dyn_ltree[_length_code[lc]+LITERALS+1].Freq++;
1.1032 + s->dyn_dtree[d_code(dist)].Freq++;
1.1033 + }
1.1034 +
1.1035 +#ifdef TRUNCATE_BLOCK
1.1036 + /* Try to guess if it is profitable to stop the current block here */
1.1037 + if ((s->last_lit & 0x1fff) == 0 && s->level > 2) {
1.1038 + /* Compute an upper bound for the compressed length */
1.1039 + ulg out_length = (ulg)s->last_lit*8L;
1.1040 + ulg in_length = (ulg)((long)s->strstart - s->block_start);
1.1041 + int dcode;
1.1042 + for (dcode = 0; dcode < D_CODES; dcode++) {
1.1043 + out_length += (ulg)s->dyn_dtree[dcode].Freq *
1.1044 + (5L+extra_dbits[dcode]);
1.1045 + }
1.1046 + out_length >>= 3;
1.1047 + Tracev((stderr,"\nlast_lit %u, in %ld, out ~%ld(%ld%%) ",
1.1048 + s->last_lit, in_length, out_length,
1.1049 + 100L - out_length*100L/in_length));
1.1050 + if (s->matches < s->last_lit/2 && out_length < in_length/2) return 1;
1.1051 + }
1.1052 +#endif
1.1053 + return (s->last_lit == s->lit_bufsize-1);
1.1054 + /* We avoid equality with lit_bufsize because of wraparound at 64K
1.1055 + * on 16 bit machines and because stored blocks are restricted to
1.1056 + * 64K-1 bytes.
1.1057 + */
1.1058 +}
1.1059 +
1.1060 +/* ===========================================================================
1.1061 + * Send the block data compressed using the given Huffman trees
1.1062 + */
1.1063 +local void compress_block(s, ltree, dtree)
1.1064 + deflate_state *s;
1.1065 + const ct_data *ltree; /* literal tree */
1.1066 + const ct_data *dtree; /* distance tree */
1.1067 +{
1.1068 + unsigned dist; /* distance of matched string */
1.1069 + int lc; /* match length or unmatched char (if dist == 0) */
1.1070 + unsigned lx = 0; /* running index in l_buf */
1.1071 + unsigned code; /* the code to send */
1.1072 + int extra; /* number of extra bits to send */
1.1073 +
1.1074 + if (s->last_lit != 0) do {
1.1075 + dist = s->d_buf[lx];
1.1076 + lc = s->l_buf[lx++];
1.1077 + if (dist == 0) {
1.1078 + send_code(s, lc, ltree); /* send a literal byte */
1.1079 + Tracecv(isgraph(lc), (stderr," '%c' ", lc));
1.1080 + } else {
1.1081 + /* Here, lc is the match length - MIN_MATCH */
1.1082 + code = _length_code[lc];
1.1083 + send_code(s, code+LITERALS+1, ltree); /* send the length code */
1.1084 + extra = extra_lbits[code];
1.1085 + if (extra != 0) {
1.1086 + lc -= base_length[code];
1.1087 + send_bits(s, lc, extra); /* send the extra length bits */
1.1088 + }
1.1089 + dist--; /* dist is now the match distance - 1 */
1.1090 + code = d_code(dist);
1.1091 + Assert (code < D_CODES, "bad d_code");
1.1092 +
1.1093 + send_code(s, code, dtree); /* send the distance code */
1.1094 + extra = extra_dbits[code];
1.1095 + if (extra != 0) {
1.1096 + dist -= base_dist[code];
1.1097 + send_bits(s, dist, extra); /* send the extra distance bits */
1.1098 + }
1.1099 + } /* literal or match pair ? */
1.1100 +
1.1101 + /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */
1.1102 + Assert((uInt)(s->pending) < s->lit_bufsize + 2*lx,
1.1103 + "pendingBuf overflow");
1.1104 +
1.1105 + } while (lx < s->last_lit);
1.1106 +
1.1107 + send_code(s, END_BLOCK, ltree);
1.1108 +}
1.1109 +
1.1110 +/* ===========================================================================
1.1111 + * Check if the data type is TEXT or BINARY, using the following algorithm:
1.1112 + * - TEXT if the two conditions below are satisfied:
1.1113 + * a) There are no non-portable control characters belonging to the
1.1114 + * "black list" (0..6, 14..25, 28..31).
1.1115 + * b) There is at least one printable character belonging to the
1.1116 + * "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
1.1117 + * - BINARY otherwise.
1.1118 + * - The following partially-portable control characters form a
1.1119 + * "gray list" that is ignored in this detection algorithm:
1.1120 + * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
1.1121 + * IN assertion: the fields Freq of dyn_ltree are set.
1.1122 + */
1.1123 +local int detect_data_type(s)
1.1124 + deflate_state *s;
1.1125 +{
1.1126 + /* black_mask is the bit mask of black-listed bytes
1.1127 + * set bits 0..6, 14..25, and 28..31
1.1128 + * 0xf3ffc07f = binary 11110011111111111100000001111111
1.1129 + */
1.1130 + unsigned long black_mask = 0xf3ffc07fUL;
1.1131 + int n;
1.1132 +
1.1133 + /* Check for non-textual ("black-listed") bytes. */
1.1134 + for (n = 0; n <= 31; n++, black_mask >>= 1)
1.1135 + if ((black_mask & 1) && (s->dyn_ltree[n].Freq != 0))
1.1136 + return Z_BINARY;
1.1137 +
1.1138 + /* Check for textual ("white-listed") bytes. */
1.1139 + if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
1.1140 + || s->dyn_ltree[13].Freq != 0)
1.1141 + return Z_TEXT;
1.1142 + for (n = 32; n < LITERALS; n++)
1.1143 + if (s->dyn_ltree[n].Freq != 0)
1.1144 + return Z_TEXT;
1.1145 +
1.1146 + /* There are no "black-listed" or "white-listed" bytes:
1.1147 + * this stream either is empty or has tolerated ("gray-listed") bytes only.
1.1148 + */
1.1149 + return Z_BINARY;
1.1150 +}
1.1151 +
1.1152 +/* ===========================================================================
1.1153 + * Reverse the first len bits of a code, using straightforward code (a faster
1.1154 + * method would use a table)
1.1155 + * IN assertion: 1 <= len <= 15
1.1156 + */
1.1157 +local unsigned bi_reverse(code, len)
1.1158 + unsigned code; /* the value to invert */
1.1159 + int len; /* its bit length */
1.1160 +{
1.1161 + register unsigned res = 0;
1.1162 + do {
1.1163 + res |= code & 1;
1.1164 + code >>= 1, res <<= 1;
1.1165 + } while (--len > 0);
1.1166 + return res >> 1;
1.1167 +}
1.1168 +
1.1169 +/* ===========================================================================
1.1170 + * Flush the bit buffer, keeping at most 7 bits in it.
1.1171 + */
1.1172 +local void bi_flush(s)
1.1173 + deflate_state *s;
1.1174 +{
1.1175 + if (s->bi_valid == 16) {
1.1176 + put_short(s, s->bi_buf);
1.1177 + s->bi_buf = 0;
1.1178 + s->bi_valid = 0;
1.1179 + } else if (s->bi_valid >= 8) {
1.1180 + put_byte(s, (Byte)s->bi_buf);
1.1181 + s->bi_buf >>= 8;
1.1182 + s->bi_valid -= 8;
1.1183 + }
1.1184 +}
1.1185 +
1.1186 +/* ===========================================================================
1.1187 + * Flush the bit buffer and align the output on a byte boundary
1.1188 + */
1.1189 +local void bi_windup(s)
1.1190 + deflate_state *s;
1.1191 +{
1.1192 + if (s->bi_valid > 8) {
1.1193 + put_short(s, s->bi_buf);
1.1194 + } else if (s->bi_valid > 0) {
1.1195 + put_byte(s, (Byte)s->bi_buf);
1.1196 + }
1.1197 + s->bi_buf = 0;
1.1198 + s->bi_valid = 0;
1.1199 +#ifdef DEBUG
1.1200 + s->bits_sent = (s->bits_sent+7) & ~7;
1.1201 +#endif
1.1202 +}
1.1203 +
1.1204 +/* ===========================================================================
1.1205 + * Copy a stored block, storing first the length and its
1.1206 + * one's complement if requested.
1.1207 + */
1.1208 +local void copy_block(s, buf, len, header)
1.1209 + deflate_state *s;
1.1210 + charf *buf; /* the input data */
1.1211 + unsigned len; /* its length */
1.1212 + int header; /* true if block header must be written */
1.1213 +{
1.1214 + bi_windup(s); /* align on byte boundary */
1.1215 +
1.1216 + if (header) {
1.1217 + put_short(s, (ush)len);
1.1218 + put_short(s, (ush)~len);
1.1219 +#ifdef DEBUG
1.1220 + s->bits_sent += 2*16;
1.1221 +#endif
1.1222 + }
1.1223 +#ifdef DEBUG
1.1224 + s->bits_sent += (ulg)len<<3;
1.1225 +#endif
1.1226 + while (len--) {
1.1227 + put_byte(s, *buf++);
1.1228 + }
1.1229 +}
