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1 | /* enough.c -- determine the maximum size of inflate's Huffman code tables over |
2 | * all possible valid and complete Huffman codes, subject to a length limit. | |
3 | * Copyright (C) 2007, 2008 Mark Adler | |
4 | * Version 1.3 17 February 2008 Mark Adler | |
5 | */ | |
6 | ||
7 | /* Version history: | |
8 | 1.0 3 Jan 2007 First version (derived from codecount.c version 1.4) | |
9 | 1.1 4 Jan 2007 Use faster incremental table usage computation | |
10 | Prune examine() search on previously visited states | |
11 | 1.2 5 Jan 2007 Comments clean up | |
12 | As inflate does, decrease root for short codes | |
13 | Refuse cases where inflate would increase root | |
14 | 1.3 17 Feb 2008 Add argument for initial root table size | |
15 | Fix bug for initial root table size == max - 1 | |
16 | Use a macro to compute the history index | |
17 | */ | |
18 | ||
19 | /* | |
20 | Examine all possible Huffman codes for a given number of symbols and a | |
21 | maximum code length in bits to determine the maximum table size for zilb's | |
22 | inflate. Only complete Huffman codes are counted. | |
23 | ||
24 | Two codes are considered distinct if the vectors of the number of codes per | |
25 | length are not identical. So permutations of the symbol assignments result | |
26 | in the same code for the counting, as do permutations of the assignments of | |
27 | the bit values to the codes (i.e. only canonical codes are counted). | |
28 | ||
29 | We build a code from shorter to longer lengths, determining how many symbols | |
30 | are coded at each length. At each step, we have how many symbols remain to | |
31 | be coded, what the last code length used was, and how many bit patterns of | |
32 | that length remain unused. Then we add one to the code length and double the | |
33 | number of unused patterns to graduate to the next code length. We then | |
34 | assign all portions of the remaining symbols to that code length that | |
35 | preserve the properties of a correct and eventually complete code. Those | |
36 | properties are: we cannot use more bit patterns than are available; and when | |
37 | all the symbols are used, there are exactly zero possible bit patterns | |
38 | remaining. | |
39 | ||
40 | The inflate Huffman decoding algorithm uses two-level lookup tables for | |
41 | speed. There is a single first-level table to decode codes up to root bits | |
42 | in length (root == 9 in the current inflate implementation). The table | |
43 | has 1 << root entries and is indexed by the next root bits of input. Codes | |
44 | shorter than root bits have replicated table entries, so that the correct | |
45 | entry is pointed to regardless of the bits that follow the short code. If | |
46 | the code is longer than root bits, then the table entry points to a second- | |
47 | level table. The size of that table is determined by the longest code with | |
48 | that root-bit prefix. If that longest code has length len, then the table | |
49 | has size 1 << (len - root), to index the remaining bits in that set of | |
50 | codes. Each subsequent root-bit prefix then has its own sub-table. The | |
51 | total number of table entries required by the code is calculated | |
52 | incrementally as the number of codes at each bit length is populated. When | |
53 | all of the codes are shorter than root bits, then root is reduced to the | |
54 | longest code length, resulting in a single, smaller, one-level table. | |
55 | ||
56 | The inflate algorithm also provides for small values of root (relative to | |
57 | the log2 of the number of symbols), where the shortest code has more bits | |
58 | than root. In that case, root is increased to the length of the shortest | |
59 | code. This program, by design, does not handle that case, so it is verified | |
60 | that the number of symbols is less than 2^(root + 1). | |
61 | ||
62 | In order to speed up the examination (by about ten orders of magnitude for | |
63 | the default arguments), the intermediate states in the build-up of a code | |
64 | are remembered and previously visited branches are pruned. The memory | |
65 | required for this will increase rapidly with the total number of symbols and | |
66 | the maximum code length in bits. However this is a very small price to pay | |
67 | for the vast speedup. | |
68 | ||
69 | First, all of the possible Huffman codes are counted, and reachable | |
70 | intermediate states are noted by a non-zero count in a saved-results array. | |
71 | Second, the intermediate states that lead to (root + 1) bit or longer codes | |
72 | are used to look at all sub-codes from those junctures for their inflate | |
73 | memory usage. (The amount of memory used is not affected by the number of | |
74 | codes of root bits or less in length.) Third, the visited states in the | |
75 | construction of those sub-codes and the associated calculation of the table | |
76 | size is recalled in order to avoid recalculating from the same juncture. | |
77 | Beginning the code examination at (root + 1) bit codes, which is enabled by | |
78 | identifying the reachable nodes, accounts for about six of the orders of | |
79 | magnitude of improvement for the default arguments. About another four | |
80 | orders of magnitude come from not revisiting previous states. Out of | |
81 | approximately 2x10^16 possible Huffman codes, only about 2x10^6 sub-codes | |
82 | need to be examined to cover all of the possible table memory usage cases | |
83 | for the default arguments of 286 symbols limited to 15-bit codes. | |
84 | ||
85 | Note that an unsigned long long type is used for counting. It is quite easy | |
86 | to exceed the capacity of an eight-byte integer with a large number of | |
87 | symbols and a large maximum code length, so multiple-precision arithmetic | |
88 | would need to replace the unsigned long long arithmetic in that case. This | |
89 | program will abort if an overflow occurs. The big_t type identifies where | |
90 | the counting takes place. | |
91 | ||
92 | An unsigned long long type is also used for calculating the number of | |
93 | possible codes remaining at the maximum length. This limits the maximum | |
94 | code length to the number of bits in a long long minus the number of bits | |
95 | needed to represent the symbols in a flat code. The code_t type identifies | |
96 | where the bit pattern counting takes place. | |
97 | */ | |
98 | ||
99 | #include <stdio.h> | |
100 | #include <stdlib.h> | |
101 | #include <string.h> | |
102 | #include <assert.h> | |
103 | ||
104 | #define local static | |
105 | ||
106 | /* special data types */ | |
107 | typedef unsigned long long big_t; /* type for code counting */ | |
108 | typedef unsigned long long code_t; /* type for bit pattern counting */ | |
109 | struct tab { /* type for been here check */ | |
110 | size_t len; /* length of bit vector in char's */ | |
111 | char *vec; /* allocated bit vector */ | |
112 | }; | |
113 | ||
114 | /* The array for saving results, num[], is indexed with this triplet: | |
115 | ||
116 | syms: number of symbols remaining to code | |
117 | left: number of available bit patterns at length len | |
118 | len: number of bits in the codes currently being assigned | |
119 | ||
120 | Those indices are constrained thusly when saving results: | |
121 | ||
122 | syms: 3..totsym (totsym == total symbols to code) | |
123 | left: 2..syms - 1, but only the evens (so syms == 8 -> 2, 4, 6) | |
124 | len: 1..max - 1 (max == maximum code length in bits) | |
125 | ||
126 | syms == 2 is not saved since that immediately leads to a single code. left | |
127 | must be even, since it represents the number of available bit patterns at | |
128 | the current length, which is double the number at the previous length. | |
129 | left ends at syms-1 since left == syms immediately results in a single code. | |
130 | (left > sym is not allowed since that would result in an incomplete code.) | |
131 | len is less than max, since the code completes immediately when len == max. | |
132 | ||
133 | The offset into the array is calculated for the three indices with the | |
134 | first one (syms) being outermost, and the last one (len) being innermost. | |
135 | We build the array with length max-1 lists for the len index, with syms-3 | |
136 | of those for each symbol. There are totsym-2 of those, with each one | |
137 | varying in length as a function of sym. See the calculation of index in | |
138 | count() for the index, and the calculation of size in main() for the size | |
139 | of the array. | |
140 | ||
141 | For the deflate example of 286 symbols limited to 15-bit codes, the array | |
142 | has 284,284 entries, taking up 2.17 MB for an 8-byte big_t. More than | |
143 | half of the space allocated for saved results is actually used -- not all | |
144 | possible triplets are reached in the generation of valid Huffman codes. | |
145 | */ | |
146 | ||
147 | /* The array for tracking visited states, done[], is itself indexed identically | |
148 | to the num[] array as described above for the (syms, left, len) triplet. | |
149 | Each element in the array is further indexed by the (mem, rem) doublet, | |
150 | where mem is the amount of inflate table space used so far, and rem is the | |
151 | remaining unused entries in the current inflate sub-table. Each indexed | |
152 | element is simply one bit indicating whether the state has been visited or | |
153 | not. Since the ranges for mem and rem are not known a priori, each bit | |
154 | vector is of a variable size, and grows as needed to accommodate the visited | |
155 | states. mem and rem are used to calculate a single index in a triangular | |
156 | array. Since the range of mem is expected in the default case to be about | |
157 | ten times larger than the range of rem, the array is skewed to reduce the | |
158 | memory usage, with eight times the range for mem than for rem. See the | |
159 | calculations for offset and bit in beenhere() for the details. | |
160 | ||
161 | For the deflate example of 286 symbols limited to 15-bit codes, the bit | |
162 | vectors grow to total approximately 21 MB, in addition to the 4.3 MB done[] | |
163 | array itself. | |
164 | */ | |
165 | ||
166 | /* Globals to avoid propagating constants or constant pointers recursively */ | |
167 | local int max; /* maximum allowed bit length for the codes */ | |
168 | local int root; /* size of base code table in bits */ | |
169 | local int large; /* largest code table so far */ | |
170 | local size_t size; /* number of elements in num and done */ | |
171 | local int *code; /* number of symbols assigned to each bit length */ | |
172 | local big_t *num; /* saved results array for code counting */ | |
173 | local struct tab *done; /* states already evaluated array */ | |
174 | ||
175 | /* Index function for num[] and done[] */ | |
176 | #define INDEX(i,j,k) (((size_t)((i-1)>>1)*((i-2)>>1)+(j>>1)-1)*(max-1)+k-1) | |
177 | ||
178 | /* Free allocated space. Uses globals code, num, and done. */ | |
179 | local void cleanup(void) | |
180 | { | |
181 | size_t n; | |
182 | ||
183 | if (done != NULL) { | |
184 | for (n = 0; n < size; n++) | |
185 | if (done[n].len) | |
186 | free(done[n].vec); | |
187 | free(done); | |
188 | } | |
189 | if (num != NULL) | |
190 | free(num); | |
191 | if (code != NULL) | |
192 | free(code); | |
193 | } | |
194 | ||
195 | /* Return the number of possible Huffman codes using bit patterns of lengths | |
196 | len through max inclusive, coding syms symbols, with left bit patterns of | |
197 | length len unused -- return -1 if there is an overflow in the counting. | |
198 | Keep a record of previous results in num to prevent repeating the same | |
199 | calculation. Uses the globals max and num. */ | |
200 | local big_t count(int syms, int len, int left) | |
201 | { | |
202 | big_t sum; /* number of possible codes from this juncture */ | |
203 | big_t got; /* value returned from count() */ | |
204 | int least; /* least number of syms to use at this juncture */ | |
205 | int most; /* most number of syms to use at this juncture */ | |
206 | int use; /* number of bit patterns to use in next call */ | |
207 | size_t index; /* index of this case in *num */ | |
208 | ||
209 | /* see if only one possible code */ | |
210 | if (syms == left) | |
211 | return 1; | |
212 | ||
213 | /* note and verify the expected state */ | |
214 | assert(syms > left && left > 0 && len < max); | |
215 | ||
216 | /* see if we've done this one already */ | |
217 | index = INDEX(syms, left, len); | |
218 | got = num[index]; | |
219 | if (got) | |
220 | return got; /* we have -- return the saved result */ | |
221 | ||
222 | /* we need to use at least this many bit patterns so that the code won't be | |
223 | incomplete at the next length (more bit patterns than symbols) */ | |
224 | least = (left << 1) - syms; | |
225 | if (least < 0) | |
226 | least = 0; | |
227 | ||
228 | /* we can use at most this many bit patterns, lest there not be enough | |
229 | available for the remaining symbols at the maximum length (if there were | |
230 | no limit to the code length, this would become: most = left - 1) */ | |
231 | most = (((code_t)left << (max - len)) - syms) / | |
232 | (((code_t)1 << (max - len)) - 1); | |
233 | ||
234 | /* count all possible codes from this juncture and add them up */ | |
235 | sum = 0; | |
236 | for (use = least; use <= most; use++) { | |
237 | got = count(syms - use, len + 1, (left - use) << 1); | |
238 | sum += got; | |
239 | if (got == -1 || sum < got) /* overflow */ | |
240 | return -1; | |
241 | } | |
242 | ||
243 | /* verify that all recursive calls are productive */ | |
244 | assert(sum != 0); | |
245 | ||
246 | /* save the result and return it */ | |
247 | num[index] = sum; | |
248 | return sum; | |
249 | } | |
250 | ||
251 | /* Return true if we've been here before, set to true if not. Set a bit in a | |
252 | bit vector to indicate visiting this state. Each (syms,len,left) state | |
253 | has a variable size bit vector indexed by (mem,rem). The bit vector is | |
254 | lengthened if needed to allow setting the (mem,rem) bit. */ | |
255 | local int beenhere(int syms, int len, int left, int mem, int rem) | |
256 | { | |
257 | size_t index; /* index for this state's bit vector */ | |
258 | size_t offset; /* offset in this state's bit vector */ | |
259 | int bit; /* mask for this state's bit */ | |
260 | size_t length; /* length of the bit vector in bytes */ | |
261 | char *vector; /* new or enlarged bit vector */ | |
262 | ||
263 | /* point to vector for (syms,left,len), bit in vector for (mem,rem) */ | |
264 | index = INDEX(syms, left, len); | |
265 | mem -= 1 << root; | |
266 | offset = (mem >> 3) + rem; | |
267 | offset = ((offset * (offset + 1)) >> 1) + rem; | |
268 | bit = 1 << (mem & 7); | |
269 | ||
270 | /* see if we've been here */ | |
271 | length = done[index].len; | |
272 | if (offset < length && (done[index].vec[offset] & bit) != 0) | |
273 | return 1; /* done this! */ | |
274 | ||
275 | /* we haven't been here before -- set the bit to show we have now */ | |
276 | ||
277 | /* see if we need to lengthen the vector in order to set the bit */ | |
278 | if (length <= offset) { | |
279 | /* if we have one already, enlarge it, zero out the appended space */ | |
280 | if (length) { | |
281 | do { | |
282 | length <<= 1; | |
283 | } while (length <= offset); | |
284 | vector = realloc(done[index].vec, length); | |
285 | if (vector != NULL) | |
286 | memset(vector + done[index].len, 0, length - done[index].len); | |
287 | } | |
288 | ||
289 | /* otherwise we need to make a new vector and zero it out */ | |
290 | else { | |
291 | length = 1 << (len - root); | |
292 | while (length <= offset) | |
293 | length <<= 1; | |
294 | vector = calloc(length, sizeof(char)); | |
295 | } | |
296 | ||
297 | /* in either case, bail if we can't get the memory */ | |
298 | if (vector == NULL) { | |
299 | fputs("abort: unable to allocate enough memory\n", stderr); | |
300 | cleanup(); | |
301 | exit(1); | |
302 | } | |
303 | ||
304 | /* install the new vector */ | |
305 | done[index].len = length; | |
306 | done[index].vec = vector; | |
307 | } | |
308 | ||
309 | /* set the bit */ | |
310 | done[index].vec[offset] |= bit; | |
311 | return 0; | |
312 | } | |
313 | ||
314 | /* Examine all possible codes from the given node (syms, len, left). Compute | |
315 | the amount of memory required to build inflate's decoding tables, where the | |
316 | number of code structures used so far is mem, and the number remaining in | |
317 | the current sub-table is rem. Uses the globals max, code, root, large, and | |
318 | done. */ | |
319 | local void examine(int syms, int len, int left, int mem, int rem) | |
320 | { | |
321 | int least; /* least number of syms to use at this juncture */ | |
322 | int most; /* most number of syms to use at this juncture */ | |
323 | int use; /* number of bit patterns to use in next call */ | |
324 | ||
325 | /* see if we have a complete code */ | |
326 | if (syms == left) { | |
327 | /* set the last code entry */ | |
328 | code[len] = left; | |
329 | ||
330 | /* complete computation of memory used by this code */ | |
331 | while (rem < left) { | |
332 | left -= rem; | |
333 | rem = 1 << (len - root); | |
334 | mem += rem; | |
335 | } | |
336 | assert(rem == left); | |
337 | ||
338 | /* if this is a new maximum, show the entries used and the sub-code */ | |
339 | if (mem > large) { | |
340 | large = mem; | |
341 | printf("max %d: ", mem); | |
342 | for (use = root + 1; use <= max; use++) | |
343 | if (code[use]) | |
344 | printf("%d[%d] ", code[use], use); | |
345 | putchar('\n'); | |
346 | fflush(stdout); | |
347 | } | |
348 | ||
349 | /* remove entries as we drop back down in the recursion */ | |
350 | code[len] = 0; | |
351 | return; | |
352 | } | |
353 | ||
354 | /* prune the tree if we can */ | |
355 | if (beenhere(syms, len, left, mem, rem)) | |
356 | return; | |
357 | ||
358 | /* we need to use at least this many bit patterns so that the code won't be | |
359 | incomplete at the next length (more bit patterns than symbols) */ | |
360 | least = (left << 1) - syms; | |
361 | if (least < 0) | |
362 | least = 0; | |
363 | ||
364 | /* we can use at most this many bit patterns, lest there not be enough | |
365 | available for the remaining symbols at the maximum length (if there were | |
366 | no limit to the code length, this would become: most = left - 1) */ | |
367 | most = (((code_t)left << (max - len)) - syms) / | |
368 | (((code_t)1 << (max - len)) - 1); | |
369 | ||
370 | /* occupy least table spaces, creating new sub-tables as needed */ | |
371 | use = least; | |
372 | while (rem < use) { | |
373 | use -= rem; | |
374 | rem = 1 << (len - root); | |
375 | mem += rem; | |
376 | } | |
377 | rem -= use; | |
378 | ||
379 | /* examine codes from here, updating table space as we go */ | |
380 | for (use = least; use <= most; use++) { | |
381 | code[len] = use; | |
382 | examine(syms - use, len + 1, (left - use) << 1, | |
383 | mem + (rem ? 1 << (len - root) : 0), rem << 1); | |
384 | if (rem == 0) { | |
385 | rem = 1 << (len - root); | |
386 | mem += rem; | |
387 | } | |
388 | rem--; | |
389 | } | |
390 | ||
391 | /* remove entries as we drop back down in the recursion */ | |
392 | code[len] = 0; | |
393 | } | |
394 | ||
395 | /* Look at all sub-codes starting with root + 1 bits. Look at only the valid | |
396 | intermediate code states (syms, left, len). For each completed code, | |
397 | calculate the amount of memory required by inflate to build the decoding | |
398 | tables. Find the maximum amount of memory required and show the code that | |
399 | requires that maximum. Uses the globals max, root, and num. */ | |
400 | local void enough(int syms) | |
401 | { | |
402 | int n; /* number of remaing symbols for this node */ | |
403 | int left; /* number of unused bit patterns at this length */ | |
404 | size_t index; /* index of this case in *num */ | |
405 | ||
406 | /* clear code */ | |
407 | for (n = 0; n <= max; n++) | |
408 | code[n] = 0; | |
409 | ||
410 | /* look at all (root + 1) bit and longer codes */ | |
411 | large = 1 << root; /* base table */ | |
412 | if (root < max) /* otherwise, there's only a base table */ | |
413 | for (n = 3; n <= syms; n++) | |
414 | for (left = 2; left < n; left += 2) | |
415 | { | |
416 | /* look at all reachable (root + 1) bit nodes, and the | |
417 | resulting codes (complete at root + 2 or more) */ | |
418 | index = INDEX(n, left, root + 1); | |
419 | if (root + 1 < max && num[index]) /* reachable node */ | |
420 | examine(n, root + 1, left, 1 << root, 0); | |
421 | ||
422 | /* also look at root bit codes with completions at root + 1 | |
423 | bits (not saved in num, since complete), just in case */ | |
424 | if (num[index - 1] && n <= left << 1) | |
425 | examine((n - left) << 1, root + 1, (n - left) << 1, | |
426 | 1 << root, 0); | |
427 | } | |
428 | ||
429 | /* done */ | |
430 | printf("done: maximum of %d table entries\n", large); | |
431 | } | |
432 | ||
433 | /* | |
434 | Examine and show the total number of possible Huffman codes for a given | |
435 | maximum number of symbols, initial root table size, and maximum code length | |
436 | in bits -- those are the command arguments in that order. The default | |
437 | values are 286, 9, and 15 respectively, for the deflate literal/length code. | |
438 | The possible codes are counted for each number of coded symbols from two to | |
439 | the maximum. The counts for each of those and the total number of codes are | |
440 | shown. The maximum number of inflate table entires is then calculated | |
441 | across all possible codes. Each new maximum number of table entries and the | |
442 | associated sub-code (starting at root + 1 == 10 bits) is shown. | |
443 | ||
444 | To count and examine Huffman codes that are not length-limited, provide a | |
445 | maximum length equal to the number of symbols minus one. | |
446 | ||
447 | For the deflate literal/length code, use "enough". For the deflate distance | |
448 | code, use "enough 30 6". | |
449 | ||
450 | This uses the %llu printf format to print big_t numbers, which assumes that | |
451 | big_t is an unsigned long long. If the big_t type is changed (for example | |
452 | to a multiple precision type), the method of printing will also need to be | |
453 | updated. | |
454 | */ | |
455 | int main(int argc, char **argv) | |
456 | { | |
457 | int syms; /* total number of symbols to code */ | |
458 | int n; /* number of symbols to code for this run */ | |
459 | big_t got; /* return value of count() */ | |
460 | big_t sum; /* accumulated number of codes over n */ | |
461 | ||
462 | /* set up globals for cleanup() */ | |
463 | code = NULL; | |
464 | num = NULL; | |
465 | done = NULL; | |
466 | ||
467 | /* get arguments -- default to the deflate literal/length code */ | |
468 | syms = 286; | |
469 | root = 9; | |
470 | max = 15; | |
471 | if (argc > 1) { | |
472 | syms = atoi(argv[1]); | |
473 | if (argc > 2) { | |
474 | root = atoi(argv[2]); | |
475 | if (argc > 3) | |
476 | max = atoi(argv[3]); | |
477 | } | |
478 | } | |
479 | if (argc > 4 || syms < 2 || root < 1 || max < 1) { | |
480 | fputs("invalid arguments, need: [sym >= 2 [root >= 1 [max >= 1]]]\n", | |
481 | stderr); | |
482 | return 1; | |
483 | } | |
484 | ||
485 | /* if not restricting the code length, the longest is syms - 1 */ | |
486 | if (max > syms - 1) | |
487 | max = syms - 1; | |
488 | ||
489 | /* determine the number of bits in a code_t */ | |
490 | n = 0; | |
491 | while (((code_t)1 << n) != 0) | |
492 | n++; | |
493 | ||
494 | /* make sure that the calculation of most will not overflow */ | |
495 | if (max > n || syms - 2 >= (((code_t)0 - 1) >> (max - 1))) { | |
496 | fputs("abort: code length too long for internal types\n", stderr); | |
497 | return 1; | |
498 | } | |
499 | ||
500 | /* reject impossible code requests */ | |
501 | if (syms - 1 > ((code_t)1 << max) - 1) { | |
502 | fprintf(stderr, "%d symbols cannot be coded in %d bits\n", | |
503 | syms, max); | |
504 | return 1; | |
505 | } | |
506 | ||
507 | /* allocate code vector */ | |
508 | code = calloc(max + 1, sizeof(int)); | |
509 | if (code == NULL) { | |
510 | fputs("abort: unable to allocate enough memory\n", stderr); | |
511 | return 1; | |
512 | } | |
513 | ||
514 | /* determine size of saved results array, checking for overflows, | |
515 | allocate and clear the array (set all to zero with calloc()) */ | |
516 | if (syms == 2) /* iff max == 1 */ | |
517 | num = NULL; /* won't be saving any results */ | |
518 | else { | |
519 | size = syms >> 1; | |
520 | if (size > ((size_t)0 - 1) / (n = (syms - 1) >> 1) || | |
521 | (size *= n, size > ((size_t)0 - 1) / (n = max - 1)) || | |
522 | (size *= n, size > ((size_t)0 - 1) / sizeof(big_t)) || | |
523 | (num = calloc(size, sizeof(big_t))) == NULL) { | |
524 | fputs("abort: unable to allocate enough memory\n", stderr); | |
525 | cleanup(); | |
526 | return 1; | |
527 | } | |
528 | } | |
529 | ||
530 | /* count possible codes for all numbers of symbols, add up counts */ | |
531 | sum = 0; | |
532 | for (n = 2; n <= syms; n++) { | |
533 | got = count(n, 1, 2); | |
534 | sum += got; | |
535 | if (got == -1 || sum < got) { /* overflow */ | |
536 | fputs("abort: can't count that high!\n", stderr); | |
537 | cleanup(); | |
538 | return 1; | |
539 | } | |
540 | printf("%llu %d-codes\n", got, n); | |
541 | } | |
542 | printf("%llu total codes for 2 to %d symbols", sum, syms); | |
543 | if (max < syms - 1) | |
544 | printf(" (%d-bit length limit)\n", max); | |
545 | else | |
546 | puts(" (no length limit)"); | |
547 | ||
548 | /* allocate and clear done array for beenhere() */ | |
549 | if (syms == 2) | |
550 | done = NULL; | |
551 | else if (size > ((size_t)0 - 1) / sizeof(struct tab) || | |
552 | (done = calloc(size, sizeof(struct tab))) == NULL) { | |
553 | fputs("abort: unable to allocate enough memory\n", stderr); | |
554 | cleanup(); | |
555 | return 1; | |
556 | } | |
557 | ||
558 | /* find and show maximum inflate table usage */ | |
559 | if (root > max) /* reduce root to max length */ | |
560 | root = max; | |
561 | if (syms < ((code_t)1 << (root + 1))) | |
562 | enough(syms); | |
563 | else | |
564 | puts("cannot handle minimum code lengths > root"); | |
565 | ||
566 | /* done */ | |
567 | cleanup(); | |
568 | return 0; | |
569 | } |