trees.c (46c3d7fc) trees.c (a04ea15d)
1/* trees.c -- output deflated data using Huffman coding
2 * Copyright (C) 1995-2021 Jean-loup Gailly
3 * detect_data_type() function provided freely by Cosmin Truta, 2006
4 * For conditions of distribution and use, see copyright notice in zlib.h
5 */
6
7/*
8 * ALGORITHM

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115struct static_tree_desc_s {
116 const ct_data *static_tree; /* static tree or NULL */
117 const intf *extra_bits; /* extra bits for each code or NULL */
118 int extra_base; /* base index for extra_bits */
119 int elems; /* max number of elements in the tree */
120 int max_length; /* max bit length for the codes */
121};
122
1/* trees.c -- output deflated data using Huffman coding
2 * Copyright (C) 1995-2021 Jean-loup Gailly
3 * detect_data_type() function provided freely by Cosmin Truta, 2006
4 * For conditions of distribution and use, see copyright notice in zlib.h
5 */
6
7/*
8 * ALGORITHM

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115struct static_tree_desc_s {
116 const ct_data *static_tree; /* static tree or NULL */
117 const intf *extra_bits; /* extra bits for each code or NULL */
118 int extra_base; /* base index for extra_bits */
119 int elems; /* max number of elements in the tree */
120 int max_length; /* max bit length for the codes */
121};
122
123local const static_tree_desc static_l_desc =
123#ifdef NO_INIT_GLOBAL_POINTERS
124# define TCONST
125#else
126# define TCONST const
127#endif
128
129local TCONST static_tree_desc static_l_desc =
124{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
125
130{static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS};
131
126local const static_tree_desc static_d_desc =
132local TCONST static_tree_desc static_d_desc =
127{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
128
133{static_dtree, extra_dbits, 0, D_CODES, MAX_BITS};
134
129local const static_tree_desc static_bl_desc =
135local TCONST static_tree_desc static_bl_desc =
130{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
131
132/* ===========================================================================
136{(const ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS};
137
138/* ===========================================================================
133 * Local (static) routines in this file.
139 * Output a short LSB first on the stream.
140 * IN assertion: there is enough room in pendingBuf.
134 */
141 */
142#define put_short(s, w) { \
143 put_byte(s, (uch)((w) & 0xff)); \
144 put_byte(s, (uch)((ush)(w) >> 8)); \
145}
135
146
136local void tr_static_init OF((void));
137local void init_block OF((deflate_state *s));
138local void pqdownheap OF((deflate_state *s, ct_data *tree, int k));
139local void gen_bitlen OF((deflate_state *s, tree_desc *desc));
140local void gen_codes OF((ct_data *tree, int max_code, ushf *bl_count));
141local void build_tree OF((deflate_state *s, tree_desc *desc));
142local void scan_tree OF((deflate_state *s, ct_data *tree, int max_code));
143local void send_tree OF((deflate_state *s, ct_data *tree, int max_code));
144local int build_bl_tree OF((deflate_state *s));
145local void send_all_trees OF((deflate_state *s, int lcodes, int dcodes,
146 int blcodes));
147local void compress_block OF((deflate_state *s, const ct_data *ltree,
148 const ct_data *dtree));
149local int detect_data_type OF((deflate_state *s));
150local unsigned bi_reverse OF((unsigned code, int len));
151local void bi_windup OF((deflate_state *s));
152local void bi_flush OF((deflate_state *s));
147/* ===========================================================================
148 * Reverse the first len bits of a code, using straightforward code (a faster
149 * method would use a table)
150 * IN assertion: 1 <= len <= 15
151 */
152local unsigned bi_reverse(unsigned code, int len) {
153 register unsigned res = 0;
154 do {
155 res |= code & 1;
156 code >>= 1, res <<= 1;
157 } while (--len > 0);
158 return res >> 1;
159}
153
160
161/* ===========================================================================
162 * Flush the bit buffer, keeping at most 7 bits in it.
163 */
164local void bi_flush(deflate_state *s) {
165 if (s->bi_valid == 16) {
166 put_short(s, s->bi_buf);
167 s->bi_buf = 0;
168 s->bi_valid = 0;
169 } else if (s->bi_valid >= 8) {
170 put_byte(s, (Byte)s->bi_buf);
171 s->bi_buf >>= 8;
172 s->bi_valid -= 8;
173 }
174}
175
176/* ===========================================================================
177 * Flush the bit buffer and align the output on a byte boundary
178 */
179local void bi_windup(deflate_state *s) {
180 if (s->bi_valid > 8) {
181 put_short(s, s->bi_buf);
182 } else if (s->bi_valid > 0) {
183 put_byte(s, (Byte)s->bi_buf);
184 }
185 s->bi_buf = 0;
186 s->bi_valid = 0;
187#ifdef ZLIB_DEBUG
188 s->bits_sent = (s->bits_sent + 7) & ~7;
189#endif
190}
191
192/* ===========================================================================
193 * Generate the codes for a given tree and bit counts (which need not be
194 * optimal).
195 * IN assertion: the array bl_count contains the bit length statistics for
196 * the given tree and the field len is set for all tree elements.
197 * OUT assertion: the field code is set for all tree elements of non
198 * zero code length.
199 */
200local void gen_codes(ct_data *tree, int max_code, ushf *bl_count) {
201 ush next_code[MAX_BITS+1]; /* next code value for each bit length */
202 unsigned code = 0; /* running code value */
203 int bits; /* bit index */
204 int n; /* code index */
205
206 /* The distribution counts are first used to generate the code values
207 * without bit reversal.
208 */
209 for (bits = 1; bits <= MAX_BITS; bits++) {
210 code = (code + bl_count[bits - 1]) << 1;
211 next_code[bits] = (ush)code;
212 }
213 /* Check that the bit counts in bl_count are consistent. The last code
214 * must be all ones.
215 */
216 Assert (code + bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1,
217 "inconsistent bit counts");
218 Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
219
220 for (n = 0; n <= max_code; n++) {
221 int len = tree[n].Len;
222 if (len == 0) continue;
223 /* Now reverse the bits */
224 tree[n].Code = (ush)bi_reverse(next_code[len]++, len);
225
226 Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
227 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len] - 1));
228 }
229}
230
154#ifdef GEN_TREES_H
231#ifdef GEN_TREES_H
155local void gen_trees_header OF((void));
232local void gen_trees_header(void);
156#endif
157
158#ifndef ZLIB_DEBUG
159# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
160 /* Send a code of the given tree. c and tree must not have side effects */
161
162#else /* !ZLIB_DEBUG */
163# define send_code(s, c, tree) \
164 { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
165 send_bits(s, tree[c].Code, tree[c].Len); }
166#endif
167
168/* ===========================================================================
233#endif
234
235#ifndef ZLIB_DEBUG
236# define send_code(s, c, tree) send_bits(s, tree[c].Code, tree[c].Len)
237 /* Send a code of the given tree. c and tree must not have side effects */
238
239#else /* !ZLIB_DEBUG */
240# define send_code(s, c, tree) \
241 { if (z_verbose>2) fprintf(stderr,"\ncd %3d ",(c)); \
242 send_bits(s, tree[c].Code, tree[c].Len); }
243#endif
244
245/* ===========================================================================
169 * Output a short LSB first on the stream.
170 * IN assertion: there is enough room in pendingBuf.
171 */
172#define put_short(s, w) { \
173 put_byte(s, (uch)((w) & 0xff)); \
174 put_byte(s, (uch)((ush)(w) >> 8)); \
175}
176
177/* ===========================================================================
178 * Send a value on a given number of bits.
179 * IN assertion: length <= 16 and value fits in length bits.
180 */
181#ifdef ZLIB_DEBUG
246 * Send a value on a given number of bits.
247 * IN assertion: length <= 16 and value fits in length bits.
248 */
249#ifdef ZLIB_DEBUG
182local void send_bits OF((deflate_state *s, int value, int length));
183
184local void send_bits(s, value, length)
185 deflate_state *s;
186 int value; /* value to send */
187 int length; /* number of bits */
188{
250local void send_bits(deflate_state *s, int value, int length) {
189 Tracevv((stderr," l %2d v %4x ", length, value));
190 Assert(length > 0 && length <= 15, "invalid length");
191 s->bits_sent += (ulg)length;
192
193 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
194 * (16 - bi_valid) bits from value, leaving (width - (16 - bi_valid))
195 * unused bits in value.
196 */

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222#endif /* ZLIB_DEBUG */
223
224
225/* the arguments must not have side effects */
226
227/* ===========================================================================
228 * Initialize the various 'constant' tables.
229 */
251 Tracevv((stderr," l %2d v %4x ", length, value));
252 Assert(length > 0 && length <= 15, "invalid length");
253 s->bits_sent += (ulg)length;
254
255 /* If not enough room in bi_buf, use (valid) bits from bi_buf and
256 * (16 - bi_valid) bits from value, leaving (width - (16 - bi_valid))
257 * unused bits in value.
258 */

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284#endif /* ZLIB_DEBUG */
285
286
287/* the arguments must not have side effects */
288
289/* ===========================================================================
290 * Initialize the various 'constant' tables.
291 */
230local void tr_static_init()
231{
292local void tr_static_init(void) {
232#if defined(GEN_TREES_H) || !defined(STDC)
233 static int static_init_done = 0;
234 int n; /* iterates over tree elements */
235 int bits; /* bit counter */
236 int length; /* length value */
237 int code; /* code value */
238 int dist; /* distance index */
239 ush bl_count[MAX_BITS+1];

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316# ifndef ZLIB_DEBUG
317# include <stdio.h>
318# endif
319
320# define SEPARATOR(i, last, width) \
321 ((i) == (last)? "\n};\n\n" : \
322 ((i) % (width) == (width) - 1 ? ",\n" : ", "))
323
293#if defined(GEN_TREES_H) || !defined(STDC)
294 static int static_init_done = 0;
295 int n; /* iterates over tree elements */
296 int bits; /* bit counter */
297 int length; /* length value */
298 int code; /* code value */
299 int dist; /* distance index */
300 ush bl_count[MAX_BITS+1];

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377# ifndef ZLIB_DEBUG
378# include <stdio.h>
379# endif
380
381# define SEPARATOR(i, last, width) \
382 ((i) == (last)? "\n};\n\n" : \
383 ((i) % (width) == (width) - 1 ? ",\n" : ", "))
384
324void gen_trees_header()
325{
385void gen_trees_header(void) {
326 FILE *header = fopen("trees.h", "w");
327 int i;
328
329 Assert (header != NULL, "Can't open trees.h");
330 fprintf(header,
331 "/* header created automatically with -DGEN_TREES_H */\n\n");
332
333 fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");

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367 SEPARATOR(i, D_CODES-1, 10));
368 }
369
370 fclose(header);
371}
372#endif /* GEN_TREES_H */
373
374/* ===========================================================================
386 FILE *header = fopen("trees.h", "w");
387 int i;
388
389 Assert (header != NULL, "Can't open trees.h");
390 fprintf(header,
391 "/* header created automatically with -DGEN_TREES_H */\n\n");
392
393 fprintf(header, "local const ct_data static_ltree[L_CODES+2] = {\n");

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427 SEPARATOR(i, D_CODES-1, 10));
428 }
429
430 fclose(header);
431}
432#endif /* GEN_TREES_H */
433
434/* ===========================================================================
435 * Initialize a new block.
436 */
437local void init_block(deflate_state *s) {
438 int n; /* iterates over tree elements */
439
440 /* Initialize the trees. */
441 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
442 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
443 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
444
445 s->dyn_ltree[END_BLOCK].Freq = 1;
446 s->opt_len = s->static_len = 0L;
447 s->sym_next = s->matches = 0;
448}
449
450/* ===========================================================================
375 * Initialize the tree data structures for a new zlib stream.
376 */
451 * Initialize the tree data structures for a new zlib stream.
452 */
377void ZLIB_INTERNAL _tr_init(s)
378 deflate_state *s;
379{
453void ZLIB_INTERNAL _tr_init(deflate_state *s) {
380 tr_static_init();
381
382 s->l_desc.dyn_tree = s->dyn_ltree;
383 s->l_desc.stat_desc = &static_l_desc;
384
385 s->d_desc.dyn_tree = s->dyn_dtree;
386 s->d_desc.stat_desc = &static_d_desc;
387

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394 s->compressed_len = 0L;
395 s->bits_sent = 0L;
396#endif
397
398 /* Initialize the first block of the first file: */
399 init_block(s);
400}
401
454 tr_static_init();
455
456 s->l_desc.dyn_tree = s->dyn_ltree;
457 s->l_desc.stat_desc = &static_l_desc;
458
459 s->d_desc.dyn_tree = s->dyn_dtree;
460 s->d_desc.stat_desc = &static_d_desc;
461

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468 s->compressed_len = 0L;
469 s->bits_sent = 0L;
470#endif
471
472 /* Initialize the first block of the first file: */
473 init_block(s);
474}
475
402/* ===========================================================================
403 * Initialize a new block.
404 */
405local void init_block(s)
406 deflate_state *s;
407{
408 int n; /* iterates over tree elements */
409
410 /* Initialize the trees. */
411 for (n = 0; n < L_CODES; n++) s->dyn_ltree[n].Freq = 0;
412 for (n = 0; n < D_CODES; n++) s->dyn_dtree[n].Freq = 0;
413 for (n = 0; n < BL_CODES; n++) s->bl_tree[n].Freq = 0;
414
415 s->dyn_ltree[END_BLOCK].Freq = 1;
416 s->opt_len = s->static_len = 0L;
417 s->sym_next = s->matches = 0;
418}
419
420#define SMALLEST 1
421/* Index within the heap array of least frequent node in the Huffman tree */
422
423
424/* ===========================================================================
425 * Remove the smallest element from the heap and recreate the heap with
426 * one less element. Updates heap and heap_len.
427 */

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441 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
442
443/* ===========================================================================
444 * Restore the heap property by moving down the tree starting at node k,
445 * exchanging a node with the smallest of its two sons if necessary, stopping
446 * when the heap property is re-established (each father smaller than its
447 * two sons).
448 */
476#define SMALLEST 1
477/* Index within the heap array of least frequent node in the Huffman tree */
478
479
480/* ===========================================================================
481 * Remove the smallest element from the heap and recreate the heap with
482 * one less element. Updates heap and heap_len.
483 */

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497 (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m]))
498
499/* ===========================================================================
500 * Restore the heap property by moving down the tree starting at node k,
501 * exchanging a node with the smallest of its two sons if necessary, stopping
502 * when the heap property is re-established (each father smaller than its
503 * two sons).
504 */
449local void pqdownheap(s, tree, k)
450 deflate_state *s;
451 ct_data *tree; /* the tree to restore */
452 int k; /* node to move down */
453{
505local void pqdownheap(deflate_state *s, ct_data *tree, int k) {
454 int v = s->heap[k];
455 int j = k << 1; /* left son of k */
456 while (j <= s->heap_len) {
457 /* Set j to the smallest of the two sons: */
458 if (j < s->heap_len &&
459 smaller(tree, s->heap[j + 1], s->heap[j], s->depth)) {
460 j++;
461 }

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476 * for the current block.
477 * IN assertion: the fields freq and dad are set, heap[heap_max] and
478 * above are the tree nodes sorted by increasing frequency.
479 * OUT assertions: the field len is set to the optimal bit length, the
480 * array bl_count contains the frequencies for each bit length.
481 * The length opt_len is updated; static_len is also updated if stree is
482 * not null.
483 */
506 int v = s->heap[k];
507 int j = k << 1; /* left son of k */
508 while (j <= s->heap_len) {
509 /* Set j to the smallest of the two sons: */
510 if (j < s->heap_len &&
511 smaller(tree, s->heap[j + 1], s->heap[j], s->depth)) {
512 j++;
513 }

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528 * for the current block.
529 * IN assertion: the fields freq and dad are set, heap[heap_max] and
530 * above are the tree nodes sorted by increasing frequency.
531 * OUT assertions: the field len is set to the optimal bit length, the
532 * array bl_count contains the frequencies for each bit length.
533 * The length opt_len is updated; static_len is also updated if stree is
534 * not null.
535 */
484local void gen_bitlen(s, desc)
485 deflate_state *s;
486 tree_desc *desc; /* the tree descriptor */
487{
536local void gen_bitlen(deflate_state *s, tree_desc *desc) {
488 ct_data *tree = desc->dyn_tree;
489 int max_code = desc->max_code;
490 const ct_data *stree = desc->stat_desc->static_tree;
491 const intf *extra = desc->stat_desc->extra_bits;
492 int base = desc->stat_desc->extra_base;
493 int max_length = desc->stat_desc->max_length;
494 int h; /* heap index */
495 int n, m; /* iterate over the tree elements */

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554 s->opt_len += ((ulg)bits - tree[m].Len) * tree[m].Freq;
555 tree[m].Len = (ush)bits;
556 }
557 n--;
558 }
559 }
560}
561
537 ct_data *tree = desc->dyn_tree;
538 int max_code = desc->max_code;
539 const ct_data *stree = desc->stat_desc->static_tree;
540 const intf *extra = desc->stat_desc->extra_bits;
541 int base = desc->stat_desc->extra_base;
542 int max_length = desc->stat_desc->max_length;
543 int h; /* heap index */
544 int n, m; /* iterate over the tree elements */

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603 s->opt_len += ((ulg)bits - tree[m].Len) * tree[m].Freq;
604 tree[m].Len = (ush)bits;
605 }
606 n--;
607 }
608 }
609}
610
562/* ===========================================================================
563 * Generate the codes for a given tree and bit counts (which need not be
564 * optimal).
565 * IN assertion: the array bl_count contains the bit length statistics for
566 * the given tree and the field len is set for all tree elements.
567 * OUT assertion: the field code is set for all tree elements of non
568 * zero code length.
569 */
570local void gen_codes(tree, max_code, bl_count)
571 ct_data *tree; /* the tree to decorate */
572 int max_code; /* largest code with non zero frequency */
573 ushf *bl_count; /* number of codes at each bit length */
574{
575 ush next_code[MAX_BITS+1]; /* next code value for each bit length */
576 unsigned code = 0; /* running code value */
577 int bits; /* bit index */
578 int n; /* code index */
611#ifdef DUMP_BL_TREE
612# include <stdio.h>
613#endif
579
614
580 /* The distribution counts are first used to generate the code values
581 * without bit reversal.
582 */
583 for (bits = 1; bits <= MAX_BITS; bits++) {
584 code = (code + bl_count[bits - 1]) << 1;
585 next_code[bits] = (ush)code;
586 }
587 /* Check that the bit counts in bl_count are consistent. The last code
588 * must be all ones.
589 */
590 Assert (code + bl_count[MAX_BITS] - 1 == (1 << MAX_BITS) - 1,
591 "inconsistent bit counts");
592 Tracev((stderr,"\ngen_codes: max_code %d ", max_code));
593
594 for (n = 0; n <= max_code; n++) {
595 int len = tree[n].Len;
596 if (len == 0) continue;
597 /* Now reverse the bits */
598 tree[n].Code = (ush)bi_reverse(next_code[len]++, len);
599
600 Tracecv(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ",
601 n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len] - 1));
602 }
603}
604
605/* ===========================================================================
606 * Construct one Huffman tree and assigns the code bit strings and lengths.
607 * Update the total bit length for the current block.
608 * IN assertion: the field freq is set for all tree elements.
609 * OUT assertions: the fields len and code are set to the optimal bit length
610 * and corresponding code. The length opt_len is updated; static_len is
611 * also updated if stree is not null. The field max_code is set.
612 */
615/* ===========================================================================
616 * Construct one Huffman tree and assigns the code bit strings and lengths.
617 * Update the total bit length for the current block.
618 * IN assertion: the field freq is set for all tree elements.
619 * OUT assertions: the fields len and code are set to the optimal bit length
620 * and corresponding code. The length opt_len is updated; static_len is
621 * also updated if stree is not null. The field max_code is set.
622 */
613local void build_tree(s, desc)
614 deflate_state *s;
615 tree_desc *desc; /* the tree descriptor */
616{
623local void build_tree(deflate_state *s, tree_desc *desc) {
617 ct_data *tree = desc->dyn_tree;
618 const ct_data *stree = desc->stat_desc->static_tree;
619 int elems = desc->stat_desc->elems;
620 int n, m; /* iterate over heap elements */
621 int max_code = -1; /* largest code with non zero frequency */
622 int node; /* new node being created */
623
624 /* Construct the initial heap, with least frequent element in

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693 /* The field len is now set, we can generate the bit codes */
694 gen_codes ((ct_data *)tree, max_code, s->bl_count);
695}
696
697/* ===========================================================================
698 * Scan a literal or distance tree to determine the frequencies of the codes
699 * in the bit length tree.
700 */
624 ct_data *tree = desc->dyn_tree;
625 const ct_data *stree = desc->stat_desc->static_tree;
626 int elems = desc->stat_desc->elems;
627 int n, m; /* iterate over heap elements */
628 int max_code = -1; /* largest code with non zero frequency */
629 int node; /* new node being created */
630
631 /* Construct the initial heap, with least frequent element in

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700 /* The field len is now set, we can generate the bit codes */
701 gen_codes ((ct_data *)tree, max_code, s->bl_count);
702}
703
704/* ===========================================================================
705 * Scan a literal or distance tree to determine the frequencies of the codes
706 * in the bit length tree.
707 */
701local void scan_tree(s, tree, max_code)
702 deflate_state *s;
703 ct_data *tree; /* the tree to be scanned */
704 int max_code; /* and its largest code of non zero frequency */
705{
708local void scan_tree(deflate_state *s, ct_data *tree, int max_code) {
706 int n; /* iterates over all tree elements */
707 int prevlen = -1; /* last emitted length */
708 int curlen; /* length of current code */
709 int nextlen = tree[0].Len; /* length of next code */
710 int count = 0; /* repeat count of the current code */
711 int max_count = 7; /* max repeat count */
712 int min_count = 4; /* min repeat count */
713

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738 }
739 }
740}
741
742/* ===========================================================================
743 * Send a literal or distance tree in compressed form, using the codes in
744 * bl_tree.
745 */
709 int n; /* iterates over all tree elements */
710 int prevlen = -1; /* last emitted length */
711 int curlen; /* length of current code */
712 int nextlen = tree[0].Len; /* length of next code */
713 int count = 0; /* repeat count of the current code */
714 int max_count = 7; /* max repeat count */
715 int min_count = 4; /* min repeat count */
716

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741 }
742 }
743}
744
745/* ===========================================================================
746 * Send a literal or distance tree in compressed form, using the codes in
747 * bl_tree.
748 */
746local void send_tree(s, tree, max_code)
747 deflate_state *s;
748 ct_data *tree; /* the tree to be scanned */
749 int max_code; /* and its largest code of non zero frequency */
750{
749local void send_tree(deflate_state *s, ct_data *tree, int max_code) {
751 int n; /* iterates over all tree elements */
752 int prevlen = -1; /* last emitted length */
753 int curlen; /* length of current code */
754 int nextlen = tree[0].Len; /* length of next code */
755 int count = 0; /* repeat count of the current code */
756 int max_count = 7; /* max repeat count */
757 int min_count = 4; /* min repeat count */
758

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789 }
790 }
791}
792
793/* ===========================================================================
794 * Construct the Huffman tree for the bit lengths and return the index in
795 * bl_order of the last bit length code to send.
796 */
750 int n; /* iterates over all tree elements */
751 int prevlen = -1; /* last emitted length */
752 int curlen; /* length of current code */
753 int nextlen = tree[0].Len; /* length of next code */
754 int count = 0; /* repeat count of the current code */
755 int max_count = 7; /* max repeat count */
756 int min_count = 4; /* min repeat count */
757

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788 }
789 }
790}
791
792/* ===========================================================================
793 * Construct the Huffman tree for the bit lengths and return the index in
794 * bl_order of the last bit length code to send.
795 */
797local int build_bl_tree(s)
798 deflate_state *s;
799{
796local int build_bl_tree(deflate_state *s) {
800 int max_blindex; /* index of last bit length code of non zero freq */
801
802 /* Determine the bit length frequencies for literal and distance trees */
803 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
804 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
805
806 /* Build the bit length tree: */
807 build_tree(s, (tree_desc *)(&(s->bl_desc)));

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824 return max_blindex;
825}
826
827/* ===========================================================================
828 * Send the header for a block using dynamic Huffman trees: the counts, the
829 * lengths of the bit length codes, the literal tree and the distance tree.
830 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
831 */
797 int max_blindex; /* index of last bit length code of non zero freq */
798
799 /* Determine the bit length frequencies for literal and distance trees */
800 scan_tree(s, (ct_data *)s->dyn_ltree, s->l_desc.max_code);
801 scan_tree(s, (ct_data *)s->dyn_dtree, s->d_desc.max_code);
802
803 /* Build the bit length tree: */
804 build_tree(s, (tree_desc *)(&(s->bl_desc)));

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821 return max_blindex;
822}
823
824/* ===========================================================================
825 * Send the header for a block using dynamic Huffman trees: the counts, the
826 * lengths of the bit length codes, the literal tree and the distance tree.
827 * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4.
828 */
832local void send_all_trees(s, lcodes, dcodes, blcodes)
833 deflate_state *s;
834 int lcodes, dcodes, blcodes; /* number of codes for each tree */
835{
829local void send_all_trees(deflate_state *s, int lcodes, int dcodes,
830 int blcodes) {
836 int rank; /* index in bl_order */
837
838 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
839 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
840 "too many codes");
841 Tracev((stderr, "\nbl counts: "));
842 send_bits(s, lcodes - 257, 5); /* not +255 as stated in appnote.txt */
843 send_bits(s, dcodes - 1, 5);

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853
854 send_tree(s, (ct_data *)s->dyn_dtree, dcodes - 1); /* distance tree */
855 Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
856}
857
858/* ===========================================================================
859 * Send a stored block
860 */
831 int rank; /* index in bl_order */
832
833 Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes");
834 Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES,
835 "too many codes");
836 Tracev((stderr, "\nbl counts: "));
837 send_bits(s, lcodes - 257, 5); /* not +255 as stated in appnote.txt */
838 send_bits(s, dcodes - 1, 5);

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848
849 send_tree(s, (ct_data *)s->dyn_dtree, dcodes - 1); /* distance tree */
850 Tracev((stderr, "\ndist tree: sent %ld", s->bits_sent));
851}
852
853/* ===========================================================================
854 * Send a stored block
855 */
861void ZLIB_INTERNAL _tr_stored_block(s, buf, stored_len, last)
862 deflate_state *s;
863 charf *buf; /* input block */
864 ulg stored_len; /* length of input block */
865 int last; /* one if this is the last block for a file */
866{
856void ZLIB_INTERNAL _tr_stored_block(deflate_state *s, charf *buf,
857 ulg stored_len, int last) {
867 send_bits(s, (STORED_BLOCK<<1) + last, 3); /* send block type */
868 bi_windup(s); /* align on byte boundary */
869 put_short(s, (ush)stored_len);
870 put_short(s, (ush)~stored_len);
871 if (stored_len)
872 zmemcpy(s->pending_buf + s->pending, (Bytef *)buf, stored_len);
873 s->pending += stored_len;
874#ifdef ZLIB_DEBUG
875 s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
876 s->compressed_len += (stored_len + 4) << 3;
877 s->bits_sent += 2*16;
878 s->bits_sent += stored_len << 3;
879#endif
880}
881
882/* ===========================================================================
883 * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
884 */
858 send_bits(s, (STORED_BLOCK<<1) + last, 3); /* send block type */
859 bi_windup(s); /* align on byte boundary */
860 put_short(s, (ush)stored_len);
861 put_short(s, (ush)~stored_len);
862 if (stored_len)
863 zmemcpy(s->pending_buf + s->pending, (Bytef *)buf, stored_len);
864 s->pending += stored_len;
865#ifdef ZLIB_DEBUG
866 s->compressed_len = (s->compressed_len + 3 + 7) & (ulg)~7L;
867 s->compressed_len += (stored_len + 4) << 3;
868 s->bits_sent += 2*16;
869 s->bits_sent += stored_len << 3;
870#endif
871}
872
873/* ===========================================================================
874 * Flush the bits in the bit buffer to pending output (leaves at most 7 bits)
875 */
885void ZLIB_INTERNAL _tr_flush_bits(s)
886 deflate_state *s;
887{
876void ZLIB_INTERNAL _tr_flush_bits(deflate_state *s) {
888 bi_flush(s);
889}
890
891/* ===========================================================================
892 * Send one empty static block to give enough lookahead for inflate.
893 * This takes 10 bits, of which 7 may remain in the bit buffer.
894 */
877 bi_flush(s);
878}
879
880/* ===========================================================================
881 * Send one empty static block to give enough lookahead for inflate.
882 * This takes 10 bits, of which 7 may remain in the bit buffer.
883 */
895void ZLIB_INTERNAL _tr_align(s)
896 deflate_state *s;
897{
884void ZLIB_INTERNAL _tr_align(deflate_state *s) {
898 send_bits(s, STATIC_TREES<<1, 3);
899 send_code(s, END_BLOCK, static_ltree);
900#ifdef ZLIB_DEBUG
901 s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
902#endif
903 bi_flush(s);
904}
905
906/* ===========================================================================
885 send_bits(s, STATIC_TREES<<1, 3);
886 send_code(s, END_BLOCK, static_ltree);
887#ifdef ZLIB_DEBUG
888 s->compressed_len += 10L; /* 3 for block type, 7 for EOB */
889#endif
890 bi_flush(s);
891}
892
893/* ===========================================================================
894 * Send the block data compressed using the given Huffman trees
895 */
896local void compress_block(deflate_state *s, const ct_data *ltree,
897 const ct_data *dtree) {
898 unsigned dist; /* distance of matched string */
899 int lc; /* match length or unmatched char (if dist == 0) */
900 unsigned sx = 0; /* running index in sym_buf */
901 unsigned code; /* the code to send */
902 int extra; /* number of extra bits to send */
903
904 if (s->sym_next != 0) do {
905 dist = s->sym_buf[sx++] & 0xff;
906 dist += (unsigned)(s->sym_buf[sx++] & 0xff) << 8;
907 lc = s->sym_buf[sx++];
908 if (dist == 0) {
909 send_code(s, lc, ltree); /* send a literal byte */
910 Tracecv(isgraph(lc), (stderr," '%c' ", lc));
911 } else {
912 /* Here, lc is the match length - MIN_MATCH */
913 code = _length_code[lc];
914 send_code(s, code + LITERALS + 1, ltree); /* send length code */
915 extra = extra_lbits[code];
916 if (extra != 0) {
917 lc -= base_length[code];
918 send_bits(s, lc, extra); /* send the extra length bits */
919 }
920 dist--; /* dist is now the match distance - 1 */
921 code = d_code(dist);
922 Assert (code < D_CODES, "bad d_code");
923
924 send_code(s, code, dtree); /* send the distance code */
925 extra = extra_dbits[code];
926 if (extra != 0) {
927 dist -= (unsigned)base_dist[code];
928 send_bits(s, dist, extra); /* send the extra distance bits */
929 }
930 } /* literal or match pair ? */
931
932 /* Check that the overlay between pending_buf and sym_buf is ok: */
933 Assert(s->pending < s->lit_bufsize + sx, "pendingBuf overflow");
934
935 } while (sx < s->sym_next);
936
937 send_code(s, END_BLOCK, ltree);
938}
939
940/* ===========================================================================
941 * Check if the data type is TEXT or BINARY, using the following algorithm:
942 * - TEXT if the two conditions below are satisfied:
943 * a) There are no non-portable control characters belonging to the
944 * "block list" (0..6, 14..25, 28..31).
945 * b) There is at least one printable character belonging to the
946 * "allow list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
947 * - BINARY otherwise.
948 * - The following partially-portable control characters form a
949 * "gray list" that is ignored in this detection algorithm:
950 * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
951 * IN assertion: the fields Freq of dyn_ltree are set.
952 */
953local int detect_data_type(deflate_state *s) {
954 /* block_mask is the bit mask of block-listed bytes
955 * set bits 0..6, 14..25, and 28..31
956 * 0xf3ffc07f = binary 11110011111111111100000001111111
957 */
958 unsigned long block_mask = 0xf3ffc07fUL;
959 int n;
960
961 /* Check for non-textual ("block-listed") bytes. */
962 for (n = 0; n <= 31; n++, block_mask >>= 1)
963 if ((block_mask & 1) && (s->dyn_ltree[n].Freq != 0))
964 return Z_BINARY;
965
966 /* Check for textual ("allow-listed") bytes. */
967 if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
968 || s->dyn_ltree[13].Freq != 0)
969 return Z_TEXT;
970 for (n = 32; n < LITERALS; n++)
971 if (s->dyn_ltree[n].Freq != 0)
972 return Z_TEXT;
973
974 /* There are no "block-listed" or "allow-listed" bytes:
975 * this stream either is empty or has tolerated ("gray-listed") bytes only.
976 */
977 return Z_BINARY;
978}
979
980/* ===========================================================================
907 * Determine the best encoding for the current block: dynamic trees, static
908 * trees or store, and write out the encoded block.
909 */
981 * Determine the best encoding for the current block: dynamic trees, static
982 * trees or store, and write out the encoded block.
983 */
910void ZLIB_INTERNAL _tr_flush_block(s, buf, stored_len, last)
911 deflate_state *s;
912 charf *buf; /* input block, or NULL if too old */
913 ulg stored_len; /* length of input block */
914 int last; /* one if this is the last block for a file */
915{
984void ZLIB_INTERNAL _tr_flush_block(deflate_state *s, charf *buf,
985 ulg stored_len, int last) {
916 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
917 int max_blindex = 0; /* index of last bit length code of non zero freq */
918
919 /* Build the Huffman trees unless a stored block is forced */
920 if (s->level > 0) {
921
922 /* Check if the file is binary or text */
923 if (s->strm->data_type == Z_UNKNOWN)

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1004 Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len >> 3,
1005 s->compressed_len - 7*last));
1006}
1007
1008/* ===========================================================================
1009 * Save the match info and tally the frequency counts. Return true if
1010 * the current block must be flushed.
1011 */
986 ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */
987 int max_blindex = 0; /* index of last bit length code of non zero freq */
988
989 /* Build the Huffman trees unless a stored block is forced */
990 if (s->level > 0) {
991
992 /* Check if the file is binary or text */
993 if (s->strm->data_type == Z_UNKNOWN)

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1074 Tracev((stderr,"\ncomprlen %lu(%lu) ", s->compressed_len >> 3,
1075 s->compressed_len - 7*last));
1076}
1077
1078/* ===========================================================================
1079 * Save the match info and tally the frequency counts. Return true if
1080 * the current block must be flushed.
1081 */
1012int ZLIB_INTERNAL _tr_tally(s, dist, lc)
1013 deflate_state *s;
1014 unsigned dist; /* distance of matched string */
1015 unsigned lc; /* match length - MIN_MATCH or unmatched char (dist==0) */
1016{
1082int ZLIB_INTERNAL _tr_tally(deflate_state *s, unsigned dist, unsigned lc) {
1017 s->sym_buf[s->sym_next++] = (uch)dist;
1018 s->sym_buf[s->sym_next++] = (uch)(dist >> 8);
1019 s->sym_buf[s->sym_next++] = (uch)lc;
1020 if (dist == 0) {
1021 /* lc is the unmatched char */
1022 s->dyn_ltree[lc].Freq++;
1023 } else {
1024 s->matches++;
1025 /* Here, lc is the match length - MIN_MATCH */
1026 dist--; /* dist = match distance - 1 */
1027 Assert((ush)dist < (ush)MAX_DIST(s) &&
1028 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
1029 (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
1030
1031 s->dyn_ltree[_length_code[lc] + LITERALS + 1].Freq++;
1032 s->dyn_dtree[d_code(dist)].Freq++;
1033 }
1034 return (s->sym_next == s->sym_end);
1035}
1083 s->sym_buf[s->sym_next++] = (uch)dist;
1084 s->sym_buf[s->sym_next++] = (uch)(dist >> 8);
1085 s->sym_buf[s->sym_next++] = (uch)lc;
1086 if (dist == 0) {
1087 /* lc is the unmatched char */
1088 s->dyn_ltree[lc].Freq++;
1089 } else {
1090 s->matches++;
1091 /* Here, lc is the match length - MIN_MATCH */
1092 dist--; /* dist = match distance - 1 */
1093 Assert((ush)dist < (ush)MAX_DIST(s) &&
1094 (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) &&
1095 (ush)d_code(dist) < (ush)D_CODES, "_tr_tally: bad match");
1096
1097 s->dyn_ltree[_length_code[lc] + LITERALS + 1].Freq++;
1098 s->dyn_dtree[d_code(dist)].Freq++;
1099 }
1100 return (s->sym_next == s->sym_end);
1101}
1036
1037/* ===========================================================================
1038 * Send the block data compressed using the given Huffman trees
1039 */
1040local void compress_block(s, ltree, dtree)
1041 deflate_state *s;
1042 const ct_data *ltree; /* literal tree */
1043 const ct_data *dtree; /* distance tree */
1044{
1045 unsigned dist; /* distance of matched string */
1046 int lc; /* match length or unmatched char (if dist == 0) */
1047 unsigned sx = 0; /* running index in sym_buf */
1048 unsigned code; /* the code to send */
1049 int extra; /* number of extra bits to send */
1050
1051 if (s->sym_next != 0) do {
1052 dist = s->sym_buf[sx++] & 0xff;
1053 dist += (unsigned)(s->sym_buf[sx++] & 0xff) << 8;
1054 lc = s->sym_buf[sx++];
1055 if (dist == 0) {
1056 send_code(s, lc, ltree); /* send a literal byte */
1057 Tracecv(isgraph(lc), (stderr," '%c' ", lc));
1058 } else {
1059 /* Here, lc is the match length - MIN_MATCH */
1060 code = _length_code[lc];
1061 send_code(s, code + LITERALS + 1, ltree); /* send length code */
1062 extra = extra_lbits[code];
1063 if (extra != 0) {
1064 lc -= base_length[code];
1065 send_bits(s, lc, extra); /* send the extra length bits */
1066 }
1067 dist--; /* dist is now the match distance - 1 */
1068 code = d_code(dist);
1069 Assert (code < D_CODES, "bad d_code");
1070
1071 send_code(s, code, dtree); /* send the distance code */
1072 extra = extra_dbits[code];
1073 if (extra != 0) {
1074 dist -= (unsigned)base_dist[code];
1075 send_bits(s, dist, extra); /* send the extra distance bits */
1076 }
1077 } /* literal or match pair ? */
1078
1079 /* Check that the overlay between pending_buf and sym_buf is ok: */
1080 Assert(s->pending < s->lit_bufsize + sx, "pendingBuf overflow");
1081
1082 } while (sx < s->sym_next);
1083
1084 send_code(s, END_BLOCK, ltree);
1085}
1086
1087/* ===========================================================================
1088 * Check if the data type is TEXT or BINARY, using the following algorithm:
1089 * - TEXT if the two conditions below are satisfied:
1090 * a) There are no non-portable control characters belonging to the
1091 * "block list" (0..6, 14..25, 28..31).
1092 * b) There is at least one printable character belonging to the
1093 * "allow list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255).
1094 * - BINARY otherwise.
1095 * - The following partially-portable control characters form a
1096 * "gray list" that is ignored in this detection algorithm:
1097 * (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}).
1098 * IN assertion: the fields Freq of dyn_ltree are set.
1099 */
1100local int detect_data_type(s)
1101 deflate_state *s;
1102{
1103 /* block_mask is the bit mask of block-listed bytes
1104 * set bits 0..6, 14..25, and 28..31
1105 * 0xf3ffc07f = binary 11110011111111111100000001111111
1106 */
1107 unsigned long block_mask = 0xf3ffc07fUL;
1108 int n;
1109
1110 /* Check for non-textual ("block-listed") bytes. */
1111 for (n = 0; n <= 31; n++, block_mask >>= 1)
1112 if ((block_mask & 1) && (s->dyn_ltree[n].Freq != 0))
1113 return Z_BINARY;
1114
1115 /* Check for textual ("allow-listed") bytes. */
1116 if (s->dyn_ltree[9].Freq != 0 || s->dyn_ltree[10].Freq != 0
1117 || s->dyn_ltree[13].Freq != 0)
1118 return Z_TEXT;
1119 for (n = 32; n < LITERALS; n++)
1120 if (s->dyn_ltree[n].Freq != 0)
1121 return Z_TEXT;
1122
1123 /* There are no "block-listed" or "allow-listed" bytes:
1124 * this stream either is empty or has tolerated ("gray-listed") bytes only.
1125 */
1126 return Z_BINARY;
1127}
1128
1129/* ===========================================================================
1130 * Reverse the first len bits of a code, using straightforward code (a faster
1131 * method would use a table)
1132 * IN assertion: 1 <= len <= 15
1133 */
1134local unsigned bi_reverse(code, len)
1135 unsigned code; /* the value to invert */
1136 int len; /* its bit length */
1137{
1138 register unsigned res = 0;
1139 do {
1140 res |= code & 1;
1141 code >>= 1, res <<= 1;
1142 } while (--len > 0);
1143 return res >> 1;
1144}
1145
1146/* ===========================================================================
1147 * Flush the bit buffer, keeping at most 7 bits in it.
1148 */
1149local void bi_flush(s)
1150 deflate_state *s;
1151{
1152 if (s->bi_valid == 16) {
1153 put_short(s, s->bi_buf);
1154 s->bi_buf = 0;
1155 s->bi_valid = 0;
1156 } else if (s->bi_valid >= 8) {
1157 put_byte(s, (Byte)s->bi_buf);
1158 s->bi_buf >>= 8;
1159 s->bi_valid -= 8;
1160 }
1161}
1162
1163/* ===========================================================================
1164 * Flush the bit buffer and align the output on a byte boundary
1165 */
1166local void bi_windup(s)
1167 deflate_state *s;
1168{
1169 if (s->bi_valid > 8) {
1170 put_short(s, s->bi_buf);
1171 } else if (s->bi_valid > 0) {
1172 put_byte(s, (Byte)s->bi_buf);
1173 }
1174 s->bi_buf = 0;
1175 s->bi_valid = 0;
1176#ifdef ZLIB_DEBUG
1177 s->bits_sent = (s->bits_sent + 7) & ~7;
1178#endif
1179}