Contents of /trunk/mkinitrd-magellan/klibc/usr/gzip/trees.c
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Fri Apr 24 18:32:46 2009 UTC (15 years, 1 month ago) by niro
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File size: 40390 byte(s)
-updated to klibc-1.5.15
1 | /* trees.c -- output deflated data using Huffman coding |
2 | * Copyright (C) 1992-1993 Jean-loup Gailly |
3 | * This is free software; you can redistribute it and/or modify it under the |
4 | * terms of the GNU General Public License, see the file COPYING. |
5 | */ |
6 | |
7 | /* |
8 | * PURPOSE |
9 | * |
10 | * Encode various sets of source values using variable-length |
11 | * binary code trees. |
12 | * |
13 | * DISCUSSION |
14 | * |
15 | * The PKZIP "deflation" process uses several Huffman trees. The more |
16 | * common source values are represented by shorter bit sequences. |
17 | * |
18 | * Each code tree is stored in the ZIP file in a compressed form |
19 | * which is itself a Huffman encoding of the lengths of |
20 | * all the code strings (in ascending order by source values). |
21 | * The actual code strings are reconstructed from the lengths in |
22 | * the UNZIP process, as described in the "application note" |
23 | * (APPNOTE.TXT) distributed as part of PKWARE's PKZIP program. |
24 | * |
25 | * REFERENCES |
26 | * |
27 | * Lynch, Thomas J. |
28 | * Data Compression: Techniques and Applications, pp. 53-55. |
29 | * Lifetime Learning Publications, 1985. ISBN 0-534-03418-7. |
30 | * |
31 | * Storer, James A. |
32 | * Data Compression: Methods and Theory, pp. 49-50. |
33 | * Computer Science Press, 1988. ISBN 0-7167-8156-5. |
34 | * |
35 | * Sedgewick, R. |
36 | * Algorithms, p290. |
37 | * Addison-Wesley, 1983. ISBN 0-201-06672-6. |
38 | * |
39 | * INTERFACE |
40 | * |
41 | * void ct_init (ush *attr, int *methodp) |
42 | * Allocate the match buffer, initialize the various tables and save |
43 | * the location of the internal file attribute (ascii/binary) and |
44 | * method (DEFLATE/STORE) |
45 | * |
46 | * void ct_tally (int dist, int lc); |
47 | * Save the match info and tally the frequency counts. |
48 | * |
49 | * long flush_block (char *buf, ulg stored_len, int eof) |
50 | * Determine the best encoding for the current block: dynamic trees, |
51 | * static trees or store, and output the encoded block to the zip |
52 | * file. Returns the total compressed length for the file so far. |
53 | * |
54 | */ |
55 | |
56 | #include <ctype.h> |
57 | |
58 | #include "tailor.h" |
59 | #include "gzip.h" |
60 | |
61 | #ifdef RCSID |
62 | static char rcsid[] = "$Id: trees.c,v 1.1 2002/08/18 00:59:21 hpa Exp $"; |
63 | #endif |
64 | |
65 | /* =========================================================================== |
66 | * Constants |
67 | */ |
68 | |
69 | #define MAX_BITS 15 |
70 | /* All codes must not exceed MAX_BITS bits */ |
71 | |
72 | #define MAX_BL_BITS 7 |
73 | /* Bit length codes must not exceed MAX_BL_BITS bits */ |
74 | |
75 | #define LENGTH_CODES 29 |
76 | /* number of length codes, not counting the special END_BLOCK code */ |
77 | |
78 | #define LITERALS 256 |
79 | /* number of literal bytes 0..255 */ |
80 | |
81 | #define END_BLOCK 256 |
82 | /* end of block literal code */ |
83 | |
84 | #define L_CODES (LITERALS+1+LENGTH_CODES) |
85 | /* number of Literal or Length codes, including the END_BLOCK code */ |
86 | |
87 | #define D_CODES 30 |
88 | /* number of distance codes */ |
89 | |
90 | #define BL_CODES 19 |
91 | /* number of codes used to transfer the bit lengths */ |
92 | |
93 | |
94 | local int extra_lbits[LENGTH_CODES] /* extra bits for each length code */ |
95 | = {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}; |
96 | |
97 | local int extra_dbits[D_CODES] /* extra bits for each distance code */ |
98 | = {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}; |
99 | |
100 | local int extra_blbits[BL_CODES]/* extra bits for each bit length code */ |
101 | = {0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7}; |
102 | |
103 | #define STORED_BLOCK 0 |
104 | #define STATIC_TREES 1 |
105 | #define DYN_TREES 2 |
106 | /* The three kinds of block type */ |
107 | |
108 | #ifndef LIT_BUFSIZE |
109 | # ifdef SMALL_MEM |
110 | # define LIT_BUFSIZE 0x2000 |
111 | # else |
112 | # ifdef MEDIUM_MEM |
113 | # define LIT_BUFSIZE 0x4000 |
114 | # else |
115 | # define LIT_BUFSIZE 0x8000 |
116 | # endif |
117 | # endif |
118 | #endif |
119 | #ifndef DIST_BUFSIZE |
120 | # define DIST_BUFSIZE LIT_BUFSIZE |
121 | #endif |
122 | /* Sizes of match buffers for literals/lengths and distances. There are |
123 | * 4 reasons for limiting LIT_BUFSIZE to 64K: |
124 | * - frequencies can be kept in 16 bit counters |
125 | * - if compression is not successful for the first block, all input data is |
126 | * still in the window so we can still emit a stored block even when input |
127 | * comes from standard input. (This can also be done for all blocks if |
128 | * LIT_BUFSIZE is not greater than 32K.) |
129 | * - if compression is not successful for a file smaller than 64K, we can |
130 | * even emit a stored file instead of a stored block (saving 5 bytes). |
131 | * - creating new Huffman trees less frequently may not provide fast |
132 | * adaptation to changes in the input data statistics. (Take for |
133 | * example a binary file with poorly compressible code followed by |
134 | * a highly compressible string table.) Smaller buffer sizes give |
135 | * fast adaptation but have of course the overhead of transmitting trees |
136 | * more frequently. |
137 | * - I can't count above 4 |
138 | * The current code is general and allows DIST_BUFSIZE < LIT_BUFSIZE (to save |
139 | * memory at the expense of compression). Some optimizations would be possible |
140 | * if we rely on DIST_BUFSIZE == LIT_BUFSIZE. |
141 | */ |
142 | #if LIT_BUFSIZE > INBUFSIZ |
143 | error cannot overlay l_buf and inbuf |
144 | #endif |
145 | |
146 | #define REP_3_6 16 |
147 | /* repeat previous bit length 3-6 times (2 bits of repeat count) */ |
148 | |
149 | #define REPZ_3_10 17 |
150 | /* repeat a zero length 3-10 times (3 bits of repeat count) */ |
151 | |
152 | #define REPZ_11_138 18 |
153 | /* repeat a zero length 11-138 times (7 bits of repeat count) */ |
154 | |
155 | /* =========================================================================== |
156 | * Local data |
157 | */ |
158 | |
159 | /* Data structure describing a single value and its code string. */ |
160 | typedef struct ct_data { |
161 | union { |
162 | ush freq; /* frequency count */ |
163 | ush code; /* bit string */ |
164 | } fc; |
165 | union { |
166 | ush dad; /* father node in Huffman tree */ |
167 | ush len; /* length of bit string */ |
168 | } dl; |
169 | } ct_data; |
170 | |
171 | #define Freq fc.freq |
172 | #define Code fc.code |
173 | #define Dad dl.dad |
174 | #define Len dl.len |
175 | |
176 | #define HEAP_SIZE (2*L_CODES+1) |
177 | /* maximum heap size */ |
178 | |
179 | local ct_data dyn_ltree[HEAP_SIZE]; /* literal and length tree */ |
180 | local ct_data dyn_dtree[2*D_CODES+1]; /* distance tree */ |
181 | |
182 | local ct_data static_ltree[L_CODES+2]; |
183 | /* The static literal tree. Since the bit lengths are imposed, there is no |
184 | * need for the L_CODES extra codes used during heap construction. However |
185 | * The codes 286 and 287 are needed to build a canonical tree (see ct_init |
186 | * below). |
187 | */ |
188 | |
189 | local ct_data static_dtree[D_CODES]; |
190 | /* The static distance tree. (Actually a trivial tree since all codes use |
191 | * 5 bits.) |
192 | */ |
193 | |
194 | local ct_data bl_tree[2*BL_CODES+1]; |
195 | /* Huffman tree for the bit lengths */ |
196 | |
197 | typedef struct tree_desc { |
198 | ct_data *dyn_tree; /* the dynamic tree */ |
199 | ct_data *static_tree; /* corresponding static tree or NULL */ |
200 | int *extra_bits; /* extra bits for each code or NULL */ |
201 | int extra_base; /* base index for extra_bits */ |
202 | int elems; /* max number of elements in the tree */ |
203 | int max_length; /* max bit length for the codes */ |
204 | int max_code; /* largest code with non zero frequency */ |
205 | } tree_desc; |
206 | |
207 | local tree_desc l_desc = |
208 | {dyn_ltree, static_ltree, extra_lbits, LITERALS+1, L_CODES, MAX_BITS, 0}; |
209 | |
210 | local tree_desc d_desc = |
211 | {dyn_dtree, static_dtree, extra_dbits, 0, D_CODES, MAX_BITS, 0}; |
212 | |
213 | local tree_desc bl_desc = |
214 | {bl_tree, (ct_data *)0, extra_blbits, 0, BL_CODES, MAX_BL_BITS, 0}; |
215 | |
216 | |
217 | local ush bl_count[MAX_BITS+1]; |
218 | /* number of codes at each bit length for an optimal tree */ |
219 | |
220 | local uch bl_order[BL_CODES] |
221 | = {16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15}; |
222 | /* The lengths of the bit length codes are sent in order of decreasing |
223 | * probability, to avoid transmitting the lengths for unused bit length codes. |
224 | */ |
225 | |
226 | local int heap[2*L_CODES+1]; /* heap used to build the Huffman trees */ |
227 | local int heap_len; /* number of elements in the heap */ |
228 | local int heap_max; /* element of largest frequency */ |
229 | /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. heap[0] is not used. |
230 | * The same heap array is used to build all trees. |
231 | */ |
232 | |
233 | local uch depth[2*L_CODES+1]; |
234 | /* Depth of each subtree used as tie breaker for trees of equal frequency */ |
235 | |
236 | local uch length_code[MAX_MATCH-MIN_MATCH+1]; |
237 | /* length code for each normalized match length (0 == MIN_MATCH) */ |
238 | |
239 | local uch dist_code[512]; |
240 | /* distance codes. The first 256 values correspond to the distances |
241 | * 3 .. 258, the last 256 values correspond to the top 8 bits of |
242 | * the 15 bit distances. |
243 | */ |
244 | |
245 | local int base_length[LENGTH_CODES]; |
246 | /* First normalized length for each code (0 = MIN_MATCH) */ |
247 | |
248 | local int base_dist[D_CODES]; |
249 | /* First normalized distance for each code (0 = distance of 1) */ |
250 | |
251 | #define l_buf inbuf |
252 | /* DECLARE(uch, l_buf, LIT_BUFSIZE); buffer for literals or lengths */ |
253 | |
254 | /* DECLARE(ush, d_buf, DIST_BUFSIZE); buffer for distances */ |
255 | |
256 | local uch flag_buf[(LIT_BUFSIZE/8)]; |
257 | /* flag_buf is a bit array distinguishing literals from lengths in |
258 | * l_buf, thus indicating the presence or absence of a distance. |
259 | */ |
260 | |
261 | local unsigned last_lit; /* running index in l_buf */ |
262 | local unsigned last_dist; /* running index in d_buf */ |
263 | local unsigned last_flags; /* running index in flag_buf */ |
264 | local uch flags; /* current flags not yet saved in flag_buf */ |
265 | local uch flag_bit; /* current bit used in flags */ |
266 | /* bits are filled in flags starting at bit 0 (least significant). |
267 | * Note: these flags are overkill in the current code since we don't |
268 | * take advantage of DIST_BUFSIZE == LIT_BUFSIZE. |
269 | */ |
270 | |
271 | local ulg opt_len; /* bit length of current block with optimal trees */ |
272 | local ulg static_len; /* bit length of current block with static trees */ |
273 | |
274 | local ulg compressed_len; /* total bit length of compressed file */ |
275 | |
276 | local ulg input_len; /* total byte length of input file */ |
277 | /* input_len is for debugging only since we can get it by other means. */ |
278 | |
279 | ush *file_type; /* pointer to UNKNOWN, BINARY or ASCII */ |
280 | int *file_method; /* pointer to DEFLATE or STORE */ |
281 | |
282 | #ifdef DEBUG |
283 | extern ulg bits_sent; /* bit length of the compressed data */ |
284 | extern long isize; /* byte length of input file */ |
285 | #endif |
286 | |
287 | extern long block_start; /* window offset of current block */ |
288 | extern unsigned strstart; /* window offset of current string */ |
289 | |
290 | /* =========================================================================== |
291 | * Local (static) routines in this file. |
292 | */ |
293 | |
294 | local void init_block OF((void)); |
295 | local void pqdownheap OF((ct_data *tree, int k)); |
296 | local void gen_bitlen OF((tree_desc *desc)); |
297 | local void gen_codes OF((ct_data *tree, int max_code)); |
298 | local void build_tree OF((tree_desc *desc)); |
299 | local void scan_tree OF((ct_data *tree, int max_code)); |
300 | local void send_tree OF((ct_data *tree, int max_code)); |
301 | local int build_bl_tree OF((void)); |
302 | local void send_all_trees OF((int lcodes, int dcodes, int blcodes)); |
303 | local void compress_block OF((ct_data *ltree, ct_data *dtree)); |
304 | local void set_file_type OF((void)); |
305 | |
306 | |
307 | #ifndef DEBUG |
308 | # define send_code(c, tree) send_bits(tree[c].Code, tree[c].Len) |
309 | /* Send a code of the given tree. c and tree must not have side effects */ |
310 | |
311 | #else /* DEBUG */ |
312 | # define send_code(c, tree) \ |
313 | { if (verbose>1) fprintf(stderr,"\ncd %3d ",(c)); \ |
314 | send_bits(tree[c].Code, tree[c].Len); } |
315 | #endif |
316 | |
317 | #define d_code(dist) \ |
318 | ((dist) < 256 ? dist_code[dist] : dist_code[256+((dist)>>7)]) |
319 | /* Mapping from a distance to a distance code. dist is the distance - 1 and |
320 | * must not have side effects. dist_code[256] and dist_code[257] are never |
321 | * used. |
322 | */ |
323 | |
324 | #define MAX(a,b) (a >= b ? a : b) |
325 | /* the arguments must not have side effects */ |
326 | |
327 | /* =========================================================================== |
328 | * Allocate the match buffer, initialize the various tables and save the |
329 | * location of the internal file attribute (ascii/binary) and method |
330 | * (DEFLATE/STORE). |
331 | */ |
332 | void ct_init(attr, methodp) |
333 | ush *attr; /* pointer to internal file attribute */ |
334 | int *methodp; /* pointer to compression method */ |
335 | { |
336 | int n; /* iterates over tree elements */ |
337 | int bits; /* bit counter */ |
338 | int length; /* length value */ |
339 | int code; /* code value */ |
340 | int dist; /* distance index */ |
341 | |
342 | file_type = attr; |
343 | file_method = methodp; |
344 | compressed_len = input_len = 0L; |
345 | |
346 | if (static_dtree[0].Len != 0) return; /* ct_init already called */ |
347 | |
348 | /* Initialize the mapping length (0..255) -> length code (0..28) */ |
349 | length = 0; |
350 | for (code = 0; code < LENGTH_CODES-1; code++) { |
351 | base_length[code] = length; |
352 | for (n = 0; n < (1<<extra_lbits[code]); n++) { |
353 | length_code[length++] = (uch)code; |
354 | } |
355 | } |
356 | Assert (length == 256, "ct_init: length != 256"); |
357 | /* Note that the length 255 (match length 258) can be represented |
358 | * in two different ways: code 284 + 5 bits or code 285, so we |
359 | * overwrite length_code[255] to use the best encoding: |
360 | */ |
361 | length_code[length-1] = (uch)code; |
362 | |
363 | /* Initialize the mapping dist (0..32K) -> dist code (0..29) */ |
364 | dist = 0; |
365 | for (code = 0 ; code < 16; code++) { |
366 | base_dist[code] = dist; |
367 | for (n = 0; n < (1<<extra_dbits[code]); n++) { |
368 | dist_code[dist++] = (uch)code; |
369 | } |
370 | } |
371 | Assert (dist == 256, "ct_init: dist != 256"); |
372 | dist >>= 7; /* from now on, all distances are divided by 128 */ |
373 | for ( ; code < D_CODES; code++) { |
374 | base_dist[code] = dist << 7; |
375 | for (n = 0; n < (1<<(extra_dbits[code]-7)); n++) { |
376 | dist_code[256 + dist++] = (uch)code; |
377 | } |
378 | } |
379 | Assert (dist == 256, "ct_init: 256+dist != 512"); |
380 | |
381 | /* Construct the codes of the static literal tree */ |
382 | for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; |
383 | n = 0; |
384 | while (n <= 143) static_ltree[n++].Len = 8, bl_count[8]++; |
385 | while (n <= 255) static_ltree[n++].Len = 9, bl_count[9]++; |
386 | while (n <= 279) static_ltree[n++].Len = 7, bl_count[7]++; |
387 | while (n <= 287) static_ltree[n++].Len = 8, bl_count[8]++; |
388 | /* Codes 286 and 287 do not exist, but we must include them in the |
389 | * tree construction to get a canonical Huffman tree (longest code |
390 | * all ones) |
391 | */ |
392 | gen_codes((ct_data *)static_ltree, L_CODES+1); |
393 | |
394 | /* The static distance tree is trivial: */ |
395 | for (n = 0; n < D_CODES; n++) { |
396 | static_dtree[n].Len = 5; |
397 | static_dtree[n].Code = bi_reverse(n, 5); |
398 | } |
399 | |
400 | /* Initialize the first block of the first file: */ |
401 | init_block(); |
402 | } |
403 | |
404 | /* =========================================================================== |
405 | * Initialize a new block. |
406 | */ |
407 | local void init_block() |
408 | { |
409 | int n; /* iterates over tree elements */ |
410 | |
411 | /* Initialize the trees. */ |
412 | for (n = 0; n < L_CODES; n++) dyn_ltree[n].Freq = 0; |
413 | for (n = 0; n < D_CODES; n++) dyn_dtree[n].Freq = 0; |
414 | for (n = 0; n < BL_CODES; n++) bl_tree[n].Freq = 0; |
415 | |
416 | dyn_ltree[END_BLOCK].Freq = 1; |
417 | opt_len = static_len = 0L; |
418 | last_lit = last_dist = last_flags = 0; |
419 | flags = 0; flag_bit = 1; |
420 | } |
421 | |
422 | #define SMALLEST 1 |
423 | /* Index within the heap array of least frequent node in the Huffman tree */ |
424 | |
425 | |
426 | /* =========================================================================== |
427 | * Remove the smallest element from the heap and recreate the heap with |
428 | * one less element. Updates heap and heap_len. |
429 | */ |
430 | #define pqremove(tree, top) \ |
431 | {\ |
432 | top = heap[SMALLEST]; \ |
433 | heap[SMALLEST] = heap[heap_len--]; \ |
434 | pqdownheap(tree, SMALLEST); \ |
435 | } |
436 | |
437 | /* =========================================================================== |
438 | * Compares to subtrees, using the tree depth as tie breaker when |
439 | * the subtrees have equal frequency. This minimizes the worst case length. |
440 | */ |
441 | #define smaller(tree, n, m) \ |
442 | (tree[n].Freq < tree[m].Freq || \ |
443 | (tree[n].Freq == tree[m].Freq && depth[n] <= depth[m])) |
444 | |
445 | /* =========================================================================== |
446 | * Restore the heap property by moving down the tree starting at node k, |
447 | * exchanging a node with the smallest of its two sons if necessary, stopping |
448 | * when the heap property is re-established (each father smaller than its |
449 | * two sons). |
450 | */ |
451 | local void pqdownheap(tree, k) |
452 | ct_data *tree; /* the tree to restore */ |
453 | int k; /* node to move down */ |
454 | { |
455 | int v = heap[k]; |
456 | int j = k << 1; /* left son of k */ |
457 | while (j <= heap_len) { |
458 | /* Set j to the smallest of the two sons: */ |
459 | if (j < heap_len && smaller(tree, heap[j+1], heap[j])) j++; |
460 | |
461 | /* Exit if v is smaller than both sons */ |
462 | if (smaller(tree, v, heap[j])) break; |
463 | |
464 | /* Exchange v with the smallest son */ |
465 | heap[k] = heap[j]; k = j; |
466 | |
467 | /* And continue down the tree, setting j to the left son of k */ |
468 | j <<= 1; |
469 | } |
470 | heap[k] = v; |
471 | } |
472 | |
473 | /* =========================================================================== |
474 | * Compute the optimal bit lengths for a tree and update the total bit length |
475 | * for the current block. |
476 | * IN assertion: the fields freq and dad are set, heap[heap_max] and |
477 | * above are the tree nodes sorted by increasing frequency. |
478 | * OUT assertions: the field len is set to the optimal bit length, the |
479 | * array bl_count contains the frequencies for each bit length. |
480 | * The length opt_len is updated; static_len is also updated if stree is |
481 | * not null. |
482 | */ |
483 | local void gen_bitlen(desc) |
484 | tree_desc *desc; /* the tree descriptor */ |
485 | { |
486 | ct_data *tree = desc->dyn_tree; |
487 | int *extra = desc->extra_bits; |
488 | int base = desc->extra_base; |
489 | int max_code = desc->max_code; |
490 | int max_length = desc->max_length; |
491 | ct_data *stree = desc->static_tree; |
492 | int h; /* heap index */ |
493 | int n, m; /* iterate over the tree elements */ |
494 | int bits; /* bit length */ |
495 | int xbits; /* extra bits */ |
496 | ush f; /* frequency */ |
497 | int overflow = 0; /* number of elements with bit length too large */ |
498 | |
499 | for (bits = 0; bits <= MAX_BITS; bits++) bl_count[bits] = 0; |
500 | |
501 | /* In a first pass, compute the optimal bit lengths (which may |
502 | * overflow in the case of the bit length tree). |
503 | */ |
504 | tree[heap[heap_max]].Len = 0; /* root of the heap */ |
505 | |
506 | for (h = heap_max+1; h < HEAP_SIZE; h++) { |
507 | n = heap[h]; |
508 | bits = tree[tree[n].Dad].Len + 1; |
509 | if (bits > max_length) bits = max_length, overflow++; |
510 | tree[n].Len = (ush)bits; |
511 | /* We overwrite tree[n].Dad which is no longer needed */ |
512 | |
513 | if (n > max_code) continue; /* not a leaf node */ |
514 | |
515 | bl_count[bits]++; |
516 | xbits = 0; |
517 | if (n >= base) xbits = extra[n-base]; |
518 | f = tree[n].Freq; |
519 | opt_len += (ulg)f * (bits + xbits); |
520 | if (stree) static_len += (ulg)f * (stree[n].Len + xbits); |
521 | } |
522 | if (overflow == 0) return; |
523 | |
524 | Trace((stderr,"\nbit length overflow\n")); |
525 | /* This happens for example on obj2 and pic of the Calgary corpus */ |
526 | |
527 | /* Find the first bit length which could increase: */ |
528 | do { |
529 | bits = max_length-1; |
530 | while (bl_count[bits] == 0) bits--; |
531 | bl_count[bits]--; /* move one leaf down the tree */ |
532 | bl_count[bits+1] += 2; /* move one overflow item as its brother */ |
533 | bl_count[max_length]--; |
534 | /* The brother of the overflow item also moves one step up, |
535 | * but this does not affect bl_count[max_length] |
536 | */ |
537 | overflow -= 2; |
538 | } while (overflow > 0); |
539 | |
540 | /* Now recompute all bit lengths, scanning in increasing frequency. |
541 | * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all |
542 | * lengths instead of fixing only the wrong ones. This idea is taken |
543 | * from 'ar' written by Haruhiko Okumura.) |
544 | */ |
545 | for (bits = max_length; bits != 0; bits--) { |
546 | n = bl_count[bits]; |
547 | while (n != 0) { |
548 | m = heap[--h]; |
549 | if (m > max_code) continue; |
550 | if (tree[m].Len != (unsigned) bits) { |
551 | Trace((stderr,"code %d bits %d->%d\n", m, tree[m].Len, bits)); |
552 | opt_len += ((long)bits-(long)tree[m].Len)*(long)tree[m].Freq; |
553 | tree[m].Len = (ush)bits; |
554 | } |
555 | n--; |
556 | } |
557 | } |
558 | } |
559 | |
560 | /* =========================================================================== |
561 | * Generate the codes for a given tree and bit counts (which need not be |
562 | * optimal). |
563 | * IN assertion: the array bl_count contains the bit length statistics for |
564 | * the given tree and the field len is set for all tree elements. |
565 | * OUT assertion: the field code is set for all tree elements of non |
566 | * zero code length. |
567 | */ |
568 | local void gen_codes (tree, max_code) |
569 | ct_data *tree; /* the tree to decorate */ |
570 | int max_code; /* largest code with non zero frequency */ |
571 | { |
572 | ush next_code[MAX_BITS+1]; /* next code value for each bit length */ |
573 | ush code = 0; /* running code value */ |
574 | int bits; /* bit index */ |
575 | int n; /* code index */ |
576 | |
577 | /* The distribution counts are first used to generate the code values |
578 | * without bit reversal. |
579 | */ |
580 | for (bits = 1; bits <= MAX_BITS; bits++) { |
581 | next_code[bits] = code = (code + bl_count[bits-1]) << 1; |
582 | } |
583 | /* Check that the bit counts in bl_count are consistent. The last code |
584 | * must be all ones. |
585 | */ |
586 | Assert (code + bl_count[MAX_BITS]-1 == (1<<MAX_BITS)-1, |
587 | "inconsistent bit counts"); |
588 | Tracev((stderr,"\ngen_codes: max_code %d ", max_code)); |
589 | |
590 | for (n = 0; n <= max_code; n++) { |
591 | int len = tree[n].Len; |
592 | if (len == 0) continue; |
593 | /* Now reverse the bits */ |
594 | tree[n].Code = bi_reverse(next_code[len]++, len); |
595 | |
596 | Tracec(tree != static_ltree, (stderr,"\nn %3d %c l %2d c %4x (%x) ", |
597 | n, (isgraph(n) ? n : ' '), len, tree[n].Code, next_code[len]-1)); |
598 | } |
599 | } |
600 | |
601 | /* =========================================================================== |
602 | * Construct one Huffman tree and assigns the code bit strings and lengths. |
603 | * Update the total bit length for the current block. |
604 | * IN assertion: the field freq is set for all tree elements. |
605 | * OUT assertions: the fields len and code are set to the optimal bit length |
606 | * and corresponding code. The length opt_len is updated; static_len is |
607 | * also updated if stree is not null. The field max_code is set. |
608 | */ |
609 | local void build_tree(desc) |
610 | tree_desc *desc; /* the tree descriptor */ |
611 | { |
612 | ct_data *tree = desc->dyn_tree; |
613 | ct_data *stree = desc->static_tree; |
614 | int elems = desc->elems; |
615 | int n, m; /* iterate over heap elements */ |
616 | int max_code = -1; /* largest code with non zero frequency */ |
617 | int node = elems; /* next internal node of the tree */ |
618 | |
619 | /* Construct the initial heap, with least frequent element in |
620 | * heap[SMALLEST]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. |
621 | * heap[0] is not used. |
622 | */ |
623 | heap_len = 0, heap_max = HEAP_SIZE; |
624 | |
625 | for (n = 0; n < elems; n++) { |
626 | if (tree[n].Freq != 0) { |
627 | heap[++heap_len] = max_code = n; |
628 | depth[n] = 0; |
629 | } else { |
630 | tree[n].Len = 0; |
631 | } |
632 | } |
633 | |
634 | /* The pkzip format requires that at least one distance code exists, |
635 | * and that at least one bit should be sent even if there is only one |
636 | * possible code. So to avoid special checks later on we force at least |
637 | * two codes of non zero frequency. |
638 | */ |
639 | while (heap_len < 2) { |
640 | int new = heap[++heap_len] = (max_code < 2 ? ++max_code : 0); |
641 | tree[new].Freq = 1; |
642 | depth[new] = 0; |
643 | opt_len--; if (stree) static_len -= stree[new].Len; |
644 | /* new is 0 or 1 so it does not have extra bits */ |
645 | } |
646 | desc->max_code = max_code; |
647 | |
648 | /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, |
649 | * establish sub-heaps of increasing lengths: |
650 | */ |
651 | for (n = heap_len/2; n >= 1; n--) pqdownheap(tree, n); |
652 | |
653 | /* Construct the Huffman tree by repeatedly combining the least two |
654 | * frequent nodes. |
655 | */ |
656 | do { |
657 | pqremove(tree, n); /* n = node of least frequency */ |
658 | m = heap[SMALLEST]; /* m = node of next least frequency */ |
659 | |
660 | heap[--heap_max] = n; /* keep the nodes sorted by frequency */ |
661 | heap[--heap_max] = m; |
662 | |
663 | /* Create a new node father of n and m */ |
664 | tree[node].Freq = tree[n].Freq + tree[m].Freq; |
665 | depth[node] = (uch) (MAX(depth[n], depth[m]) + 1); |
666 | tree[n].Dad = tree[m].Dad = (ush)node; |
667 | #ifdef DUMP_BL_TREE |
668 | if (tree == bl_tree) { |
669 | fprintf(stderr,"\nnode %d(%d), sons %d(%d) %d(%d)", |
670 | node, tree[node].Freq, n, tree[n].Freq, m, tree[m].Freq); |
671 | } |
672 | #endif |
673 | /* and insert the new node in the heap */ |
674 | heap[SMALLEST] = node++; |
675 | pqdownheap(tree, SMALLEST); |
676 | |
677 | } while (heap_len >= 2); |
678 | |
679 | heap[--heap_max] = heap[SMALLEST]; |
680 | |
681 | /* At this point, the fields freq and dad are set. We can now |
682 | * generate the bit lengths. |
683 | */ |
684 | gen_bitlen((tree_desc *)desc); |
685 | |
686 | /* The field len is now set, we can generate the bit codes */ |
687 | gen_codes ((ct_data *)tree, max_code); |
688 | } |
689 | |
690 | /* =========================================================================== |
691 | * Scan a literal or distance tree to determine the frequencies of the codes |
692 | * in the bit length tree. Updates opt_len to take into account the repeat |
693 | * counts. (The contribution of the bit length codes will be added later |
694 | * during the construction of bl_tree.) |
695 | */ |
696 | local void scan_tree (tree, max_code) |
697 | ct_data *tree; /* the tree to be scanned */ |
698 | int max_code; /* and its largest code of non zero frequency */ |
699 | { |
700 | int n; /* iterates over all tree elements */ |
701 | int prevlen = -1; /* last emitted length */ |
702 | int curlen; /* length of current code */ |
703 | int nextlen = tree[0].Len; /* length of next code */ |
704 | int count = 0; /* repeat count of the current code */ |
705 | int max_count = 7; /* max repeat count */ |
706 | int min_count = 4; /* min repeat count */ |
707 | |
708 | if (nextlen == 0) max_count = 138, min_count = 3; |
709 | tree[max_code+1].Len = (ush)0xffff; /* guard */ |
710 | |
711 | for (n = 0; n <= max_code; n++) { |
712 | curlen = nextlen; nextlen = tree[n+1].Len; |
713 | if (++count < max_count && curlen == nextlen) { |
714 | continue; |
715 | } else if (count < min_count) { |
716 | bl_tree[curlen].Freq += count; |
717 | } else if (curlen != 0) { |
718 | if (curlen != prevlen) bl_tree[curlen].Freq++; |
719 | bl_tree[REP_3_6].Freq++; |
720 | } else if (count <= 10) { |
721 | bl_tree[REPZ_3_10].Freq++; |
722 | } else { |
723 | bl_tree[REPZ_11_138].Freq++; |
724 | } |
725 | count = 0; prevlen = curlen; |
726 | if (nextlen == 0) { |
727 | max_count = 138, min_count = 3; |
728 | } else if (curlen == nextlen) { |
729 | max_count = 6, min_count = 3; |
730 | } else { |
731 | max_count = 7, min_count = 4; |
732 | } |
733 | } |
734 | } |
735 | |
736 | /* =========================================================================== |
737 | * Send a literal or distance tree in compressed form, using the codes in |
738 | * bl_tree. |
739 | */ |
740 | local void send_tree (tree, max_code) |
741 | ct_data *tree; /* the tree to be scanned */ |
742 | int max_code; /* and its largest code of non zero frequency */ |
743 | { |
744 | int n; /* iterates over all tree elements */ |
745 | int prevlen = -1; /* last emitted length */ |
746 | int curlen; /* length of current code */ |
747 | int nextlen = tree[0].Len; /* length of next code */ |
748 | int count = 0; /* repeat count of the current code */ |
749 | int max_count = 7; /* max repeat count */ |
750 | int min_count = 4; /* min repeat count */ |
751 | |
752 | /* tree[max_code+1].Len = -1; */ /* guard already set */ |
753 | if (nextlen == 0) max_count = 138, min_count = 3; |
754 | |
755 | for (n = 0; n <= max_code; n++) { |
756 | curlen = nextlen; nextlen = tree[n+1].Len; |
757 | if (++count < max_count && curlen == nextlen) { |
758 | continue; |
759 | } else if (count < min_count) { |
760 | do { send_code(curlen, bl_tree); } while (--count != 0); |
761 | |
762 | } else if (curlen != 0) { |
763 | if (curlen != prevlen) { |
764 | send_code(curlen, bl_tree); count--; |
765 | } |
766 | Assert(count >= 3 && count <= 6, " 3_6?"); |
767 | send_code(REP_3_6, bl_tree); send_bits(count-3, 2); |
768 | |
769 | } else if (count <= 10) { |
770 | send_code(REPZ_3_10, bl_tree); send_bits(count-3, 3); |
771 | |
772 | } else { |
773 | send_code(REPZ_11_138, bl_tree); send_bits(count-11, 7); |
774 | } |
775 | count = 0; prevlen = curlen; |
776 | if (nextlen == 0) { |
777 | max_count = 138, min_count = 3; |
778 | } else if (curlen == nextlen) { |
779 | max_count = 6, min_count = 3; |
780 | } else { |
781 | max_count = 7, min_count = 4; |
782 | } |
783 | } |
784 | } |
785 | |
786 | /* =========================================================================== |
787 | * Construct the Huffman tree for the bit lengths and return the index in |
788 | * bl_order of the last bit length code to send. |
789 | */ |
790 | local int build_bl_tree() |
791 | { |
792 | int max_blindex; /* index of last bit length code of non zero freq */ |
793 | |
794 | /* Determine the bit length frequencies for literal and distance trees */ |
795 | scan_tree((ct_data *)dyn_ltree, l_desc.max_code); |
796 | scan_tree((ct_data *)dyn_dtree, d_desc.max_code); |
797 | |
798 | /* Build the bit length tree: */ |
799 | build_tree((tree_desc *)(&bl_desc)); |
800 | /* opt_len now includes the length of the tree representations, except |
801 | * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. |
802 | */ |
803 | |
804 | /* Determine the number of bit length codes to send. The pkzip format |
805 | * requires that at least 4 bit length codes be sent. (appnote.txt says |
806 | * 3 but the actual value used is 4.) |
807 | */ |
808 | for (max_blindex = BL_CODES-1; max_blindex >= 3; max_blindex--) { |
809 | if (bl_tree[bl_order[max_blindex]].Len != 0) break; |
810 | } |
811 | /* Update opt_len to include the bit length tree and counts */ |
812 | opt_len += 3*(max_blindex+1) + 5+5+4; |
813 | Tracev((stderr, "\ndyn trees: dyn %ld, stat %ld", opt_len, static_len)); |
814 | |
815 | return max_blindex; |
816 | } |
817 | |
818 | /* =========================================================================== |
819 | * Send the header for a block using dynamic Huffman trees: the counts, the |
820 | * lengths of the bit length codes, the literal tree and the distance tree. |
821 | * IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. |
822 | */ |
823 | local void send_all_trees(lcodes, dcodes, blcodes) |
824 | int lcodes, dcodes, blcodes; /* number of codes for each tree */ |
825 | { |
826 | int rank; /* index in bl_order */ |
827 | |
828 | Assert (lcodes >= 257 && dcodes >= 1 && blcodes >= 4, "not enough codes"); |
829 | Assert (lcodes <= L_CODES && dcodes <= D_CODES && blcodes <= BL_CODES, |
830 | "too many codes"); |
831 | Tracev((stderr, "\nbl counts: ")); |
832 | send_bits(lcodes-257, 5); /* not +255 as stated in appnote.txt */ |
833 | send_bits(dcodes-1, 5); |
834 | send_bits(blcodes-4, 4); /* not -3 as stated in appnote.txt */ |
835 | for (rank = 0; rank < blcodes; rank++) { |
836 | Tracev((stderr, "\nbl code %2d ", bl_order[rank])); |
837 | send_bits(bl_tree[bl_order[rank]].Len, 3); |
838 | } |
839 | Tracev((stderr, "\nbl tree: sent %ld", bits_sent)); |
840 | |
841 | send_tree((ct_data *)dyn_ltree, lcodes-1); /* send the literal tree */ |
842 | Tracev((stderr, "\nlit tree: sent %ld", bits_sent)); |
843 | |
844 | send_tree((ct_data *)dyn_dtree, dcodes-1); /* send the distance tree */ |
845 | Tracev((stderr, "\ndist tree: sent %ld", bits_sent)); |
846 | } |
847 | |
848 | /* =========================================================================== |
849 | * Determine the best encoding for the current block: dynamic trees, static |
850 | * trees or store, and output the encoded block to the zip file. This function |
851 | * returns the total compressed length for the file so far. |
852 | */ |
853 | ulg flush_block(buf, stored_len, eof) |
854 | char *buf; /* input block, or NULL if too old */ |
855 | ulg stored_len; /* length of input block */ |
856 | int eof; /* true if this is the last block for a file */ |
857 | { |
858 | ulg opt_lenb, static_lenb; /* opt_len and static_len in bytes */ |
859 | int max_blindex; /* index of last bit length code of non zero freq */ |
860 | |
861 | flag_buf[last_flags] = flags; /* Save the flags for the last 8 items */ |
862 | |
863 | /* Check if the file is ascii or binary */ |
864 | if (*file_type == (ush)UNKNOWN) set_file_type(); |
865 | |
866 | /* Construct the literal and distance trees */ |
867 | build_tree((tree_desc *)(&l_desc)); |
868 | Tracev((stderr, "\nlit data: dyn %ld, stat %ld", opt_len, static_len)); |
869 | |
870 | build_tree((tree_desc *)(&d_desc)); |
871 | Tracev((stderr, "\ndist data: dyn %ld, stat %ld", opt_len, static_len)); |
872 | /* At this point, opt_len and static_len are the total bit lengths of |
873 | * the compressed block data, excluding the tree representations. |
874 | */ |
875 | |
876 | /* Build the bit length tree for the above two trees, and get the index |
877 | * in bl_order of the last bit length code to send. |
878 | */ |
879 | max_blindex = build_bl_tree(); |
880 | |
881 | /* Determine the best encoding. Compute first the block length in bytes */ |
882 | opt_lenb = (opt_len+3+7)>>3; |
883 | static_lenb = (static_len+3+7)>>3; |
884 | input_len += stored_len; /* for debugging only */ |
885 | |
886 | Trace((stderr, "\nopt %lu(%lu) stat %lu(%lu) stored %lu lit %u dist %u ", |
887 | opt_lenb, opt_len, static_lenb, static_len, stored_len, |
888 | last_lit, last_dist)); |
889 | |
890 | if (static_lenb <= opt_lenb) opt_lenb = static_lenb; |
891 | |
892 | /* If compression failed and this is the first and last block, |
893 | * and if the zip file can be seeked (to rewrite the local header), |
894 | * the whole file is transformed into a stored file: |
895 | */ |
896 | #ifdef FORCE_METHOD |
897 | if (level == 1 && eof && compressed_len == 0L) { /* force stored file */ |
898 | #else |
899 | if (stored_len <= opt_lenb && eof && compressed_len == 0L && seekable()) { |
900 | #endif |
901 | /* Since LIT_BUFSIZE <= 2*WSIZE, the input data must be there: */ |
902 | if (buf == (char*)0) error ("block vanished"); |
903 | |
904 | copy_block(buf, (unsigned)stored_len, 0); /* without header */ |
905 | compressed_len = stored_len << 3; |
906 | *file_method = STORED; |
907 | |
908 | #ifdef FORCE_METHOD |
909 | } else if (level == 2 && buf != (char*)0) { /* force stored block */ |
910 | #else |
911 | } else if (stored_len+4 <= opt_lenb && buf != (char*)0) { |
912 | /* 4: two words for the lengths */ |
913 | #endif |
914 | /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. |
915 | * Otherwise we can't have processed more than WSIZE input bytes since |
916 | * the last block flush, because compression would have been |
917 | * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to |
918 | * transform a block into a stored block. |
919 | */ |
920 | send_bits((STORED_BLOCK<<1)+eof, 3); /* send block type */ |
921 | compressed_len = (compressed_len + 3 + 7) & ~7L; |
922 | compressed_len += (stored_len + 4) << 3; |
923 | |
924 | copy_block(buf, (unsigned)stored_len, 1); /* with header */ |
925 | |
926 | #ifdef FORCE_METHOD |
927 | } else if (level == 3) { /* force static trees */ |
928 | #else |
929 | } else if (static_lenb == opt_lenb) { |
930 | #endif |
931 | send_bits((STATIC_TREES<<1)+eof, 3); |
932 | compress_block((ct_data *)static_ltree, (ct_data *)static_dtree); |
933 | compressed_len += 3 + static_len; |
934 | } else { |
935 | send_bits((DYN_TREES<<1)+eof, 3); |
936 | send_all_trees(l_desc.max_code+1, d_desc.max_code+1, max_blindex+1); |
937 | compress_block((ct_data *)dyn_ltree, (ct_data *)dyn_dtree); |
938 | compressed_len += 3 + opt_len; |
939 | } |
940 | Assert (compressed_len == bits_sent, "bad compressed size"); |
941 | init_block(); |
942 | |
943 | if (eof) { |
944 | Assert (input_len == isize, "bad input size"); |
945 | bi_windup(); |
946 | compressed_len += 7; /* align on byte boundary */ |
947 | } |
948 | Tracev((stderr,"\ncomprlen %lu(%lu) ", compressed_len>>3, |
949 | compressed_len-7*eof)); |
950 | |
951 | return compressed_len >> 3; |
952 | } |
953 | |
954 | /* =========================================================================== |
955 | * Save the match info and tally the frequency counts. Return true if |
956 | * the current block must be flushed. |
957 | */ |
958 | int ct_tally (dist, lc) |
959 | int dist; /* distance of matched string */ |
960 | int lc; /* match length-MIN_MATCH or unmatched char (if dist==0) */ |
961 | { |
962 | l_buf[last_lit++] = (uch)lc; |
963 | if (dist == 0) { |
964 | /* lc is the unmatched char */ |
965 | dyn_ltree[lc].Freq++; |
966 | } else { |
967 | /* Here, lc is the match length - MIN_MATCH */ |
968 | dist--; /* dist = match distance - 1 */ |
969 | Assert((ush)dist < (ush)MAX_DIST && |
970 | (ush)lc <= (ush)(MAX_MATCH-MIN_MATCH) && |
971 | (ush)d_code(dist) < (ush)D_CODES, "ct_tally: bad match"); |
972 | |
973 | dyn_ltree[length_code[lc]+LITERALS+1].Freq++; |
974 | dyn_dtree[d_code(dist)].Freq++; |
975 | |
976 | d_buf[last_dist++] = (ush)dist; |
977 | flags |= flag_bit; |
978 | } |
979 | flag_bit <<= 1; |
980 | |
981 | /* Output the flags if they fill a byte: */ |
982 | if ((last_lit & 7) == 0) { |
983 | flag_buf[last_flags++] = flags; |
984 | flags = 0, flag_bit = 1; |
985 | } |
986 | /* Try to guess if it is profitable to stop the current block here */ |
987 | if (level > 2 && (last_lit & 0xfff) == 0) { |
988 | /* Compute an upper bound for the compressed length */ |
989 | ulg out_length = (ulg)last_lit*8L; |
990 | ulg in_length = (ulg)strstart-block_start; |
991 | int dcode; |
992 | for (dcode = 0; dcode < D_CODES; dcode++) { |
993 | out_length += (ulg)dyn_dtree[dcode].Freq*(5L+extra_dbits[dcode]); |
994 | } |
995 | out_length >>= 3; |
996 | Trace((stderr,"\nlast_lit %u, last_dist %u, in %ld, out ~%ld(%ld%%) ", |
997 | last_lit, last_dist, in_length, out_length, |
998 | 100L - out_length*100L/in_length)); |
999 | if (last_dist < last_lit/2 && out_length < in_length/2) return 1; |
1000 | } |
1001 | return (last_lit == LIT_BUFSIZE-1 || last_dist == DIST_BUFSIZE); |
1002 | /* We avoid equality with LIT_BUFSIZE because of wraparound at 64K |
1003 | * on 16 bit machines and because stored blocks are restricted to |
1004 | * 64K-1 bytes. |
1005 | */ |
1006 | } |
1007 | |
1008 | /* =========================================================================== |
1009 | * Send the block data compressed using the given Huffman trees |
1010 | */ |
1011 | local void compress_block(ltree, dtree) |
1012 | ct_data *ltree; /* literal tree */ |
1013 | ct_data *dtree; /* distance tree */ |
1014 | { |
1015 | unsigned dist; /* distance of matched string */ |
1016 | int lc; /* match length or unmatched char (if dist == 0) */ |
1017 | unsigned lx = 0; /* running index in l_buf */ |
1018 | unsigned dx = 0; /* running index in d_buf */ |
1019 | unsigned fx = 0; /* running index in flag_buf */ |
1020 | uch flag = 0; /* current flags */ |
1021 | unsigned code; /* the code to send */ |
1022 | int extra; /* number of extra bits to send */ |
1023 | |
1024 | if (last_lit != 0) do { |
1025 | if ((lx & 7) == 0) flag = flag_buf[fx++]; |
1026 | lc = l_buf[lx++]; |
1027 | if ((flag & 1) == 0) { |
1028 | send_code(lc, ltree); /* send a literal byte */ |
1029 | Tracecv(isgraph(lc), (stderr," '%c' ", lc)); |
1030 | } else { |
1031 | /* Here, lc is the match length - MIN_MATCH */ |
1032 | code = length_code[lc]; |
1033 | send_code(code+LITERALS+1, ltree); /* send the length code */ |
1034 | extra = extra_lbits[code]; |
1035 | if (extra != 0) { |
1036 | lc -= base_length[code]; |
1037 | send_bits(lc, extra); /* send the extra length bits */ |
1038 | } |
1039 | dist = d_buf[dx++]; |
1040 | /* Here, dist is the match distance - 1 */ |
1041 | code = d_code(dist); |
1042 | Assert (code < D_CODES, "bad d_code"); |
1043 | |
1044 | send_code(code, dtree); /* send the distance code */ |
1045 | extra = extra_dbits[code]; |
1046 | if (extra != 0) { |
1047 | dist -= base_dist[code]; |
1048 | send_bits(dist, extra); /* send the extra distance bits */ |
1049 | } |
1050 | } /* literal or match pair ? */ |
1051 | flag >>= 1; |
1052 | } while (lx < last_lit); |
1053 | |
1054 | send_code(END_BLOCK, ltree); |
1055 | } |
1056 | |
1057 | /* =========================================================================== |
1058 | * Set the file type to ASCII or BINARY, using a crude approximation: |
1059 | * binary if more than 20% of the bytes are <= 6 or >= 128, ascii otherwise. |
1060 | * IN assertion: the fields freq of dyn_ltree are set and the total of all |
1061 | * frequencies does not exceed 64K (to fit in an int on 16 bit machines). |
1062 | */ |
1063 | local void set_file_type() |
1064 | { |
1065 | int n = 0; |
1066 | unsigned ascii_freq = 0; |
1067 | unsigned bin_freq = 0; |
1068 | while (n < 7) bin_freq += dyn_ltree[n++].Freq; |
1069 | while (n < 128) ascii_freq += dyn_ltree[n++].Freq; |
1070 | while (n < LITERALS) bin_freq += dyn_ltree[n++].Freq; |
1071 | *file_type = bin_freq > (ascii_freq >> 2) ? BINARY : ASCII; |
1072 | if (*file_type == BINARY && translate_eol) { |
1073 | warn("-l used on binary file", ""); |
1074 | } |
1075 | } |