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1 | // |
2 | // Copyright (c) 2013-2017 Vinnie Falco (vinnie dot falco at gmail dot com) | |
3 | // | |
4 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
5 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) | |
6 | // | |
7 | // This is a derivative work based on Zlib, copyright below: | |
8 | /* | |
9 | Copyright (C) 1995-2013 Jean-loup Gailly and Mark Adler | |
10 | ||
11 | This software is provided 'as-is', without any express or implied | |
12 | warranty. In no event will the authors be held liable for any damages | |
13 | arising from the use of this software. | |
14 | ||
15 | Permission is granted to anyone to use this software for any purpose, | |
16 | including commercial applications, and to alter it and redistribute it | |
17 | freely, subject to the following restrictions: | |
18 | ||
19 | 1. The origin of this software must not be misrepresented; you must not | |
20 | claim that you wrote the original software. If you use this software | |
21 | in a product, an acknowledgment in the product documentation would be | |
22 | appreciated but is not required. | |
23 | 2. Altered source versions must be plainly marked as such, and must not be | |
24 | misrepresented as being the original software. | |
25 | 3. This notice may not be removed or altered from any source distribution. | |
26 | ||
27 | Jean-loup Gailly Mark Adler | |
28 | jloup@gzip.org madler@alumni.caltech.edu | |
29 | ||
30 | The data format used by the zlib library is described by RFCs (Request for | |
31 | Comments) 1950 to 1952 in the files http://tools.ietf.org/html/rfc1950 | |
32 | (zlib format), rfc1951 (deflate format) and rfc1952 (gzip format). | |
33 | */ | |
34 | ||
35 | #ifndef BEAST_ZLIB_DETAIL_DEFLATE_STREAM_HPP | |
36 | #define BEAST_ZLIB_DETAIL_DEFLATE_STREAM_HPP | |
37 | ||
38 | #include <beast/zlib/zlib.hpp> | |
39 | #include <beast/zlib/detail/ranges.hpp> | |
40 | #include <beast/core/detail/type_traits.hpp> | |
41 | #include <boost/assert.hpp> | |
42 | #include <boost/optional.hpp> | |
43 | #include <cstdint> | |
44 | #include <cstdlib> | |
45 | #include <cstring> | |
46 | #include <memory> | |
47 | #include <stdexcept> | |
48 | #include <type_traits> | |
49 | ||
50 | namespace beast { | |
51 | namespace zlib { | |
52 | namespace detail { | |
53 | ||
54 | /* | |
55 | * ALGORITHM | |
56 | * | |
57 | * The "deflation" process depends on being able to identify portions | |
58 | * of the input text which are identical to earlier input (within a | |
59 | * sliding window trailing behind the input currently being processed). | |
60 | * | |
61 | * Each code tree is stored in a compressed form which is itself | |
62 | * a Huffman encoding of the lengths of all the code strings (in | |
63 | * ascending order by source values). The actual code strings are | |
64 | * reconstructed from the lengths in the inflate process, as described | |
65 | * in the deflate specification. | |
66 | * | |
67 | * The most straightforward technique turns out to be the fastest for | |
68 | * most input files: try all possible matches and select the longest. | |
69 | * The key feature of this algorithm is that insertions into the string | |
70 | * dictionary are very simple and thus fast, and deletions are avoided | |
71 | * completely. Insertions are performed at each input character, whereas | |
72 | * string matches are performed only when the previous match ends. So it | |
73 | * is preferable to spend more time in matches to allow very fast string | |
74 | * insertions and avoid deletions. The matching algorithm for small | |
75 | * strings is inspired from that of Rabin & Karp. A brute force approach | |
76 | * is used to find longer strings when a small match has been found. | |
77 | * A similar algorithm is used in comic (by Jan-Mark Wams) and freeze | |
78 | * (by Leonid Broukhis). | |
79 | * A previous version of this file used a more sophisticated algorithm | |
80 | * (by Fiala and Greene) which is guaranteed to run in linear amortized | |
81 | * time, but has a larger average cost, uses more memory and is patented. | |
82 | * However the F&G algorithm may be faster for some highly redundant | |
83 | * files if the parameter max_chain_length (described below) is too large. | |
84 | * | |
85 | * ACKNOWLEDGEMENTS | |
86 | * | |
87 | * The idea of lazy evaluation of matches is due to Jan-Mark Wams, and | |
88 | * I found it in 'freeze' written by Leonid Broukhis. | |
89 | * Thanks to many people for bug reports and testing. | |
90 | * | |
91 | * REFERENCES | |
92 | * | |
93 | * Deutsch, L.P.,"DEFLATE Compressed Data Format Specification". | |
94 | * Available in http://tools.ietf.org/html/rfc1951 | |
95 | * | |
96 | * A description of the Rabin and Karp algorithm is given in the book | |
97 | * "Algorithms" by R. Sedgewick, Addison-Wesley, p252. | |
98 | * | |
99 | * Fiala,E.R., and Greene,D.H. | |
100 | * Data Compression with Finite Windows, Comm.ACM, 32,4 (1989) 490-595 | |
101 | * | |
102 | */ | |
103 | ||
104 | class deflate_stream | |
105 | { | |
106 | protected: | |
107 | // Upper limit on code length | |
108 | static std::uint8_t constexpr maxBits = 15; | |
109 | ||
110 | // Number of length codes, not counting the special END_BLOCK code | |
111 | static std::uint16_t constexpr lengthCodes = 29; | |
112 | ||
113 | // Number of literal bytes 0..255 | |
114 | static std::uint16_t constexpr literals = 256; | |
115 | ||
116 | // Number of Literal or Length codes, including the END_BLOCK code | |
117 | static std::uint16_t constexpr lCodes = literals + 1 + lengthCodes; | |
118 | ||
119 | // Number of distance code lengths | |
120 | static std::uint16_t constexpr dCodes = 30; | |
121 | ||
122 | // Number of codes used to transfer the bit lengths | |
123 | static std::uint16_t constexpr blCodes = 19; | |
124 | ||
125 | // Number of distance codes | |
126 | static std::uint16_t constexpr distCodeLen = 512; | |
127 | ||
128 | // Size limit on bit length codes | |
129 | static std::uint8_t constexpr maxBlBits= 7; | |
130 | ||
131 | static std::uint16_t constexpr minMatch = 3; | |
132 | static std::uint16_t constexpr maxMatch = 258; | |
133 | ||
134 | // Can't change minMatch without also changing code, see original zlib | |
135 | static_assert(minMatch==3, ""); | |
136 | ||
137 | // end of block literal code | |
138 | static std::uint16_t constexpr END_BLOCK = 256; | |
139 | ||
140 | // repeat previous bit length 3-6 times (2 bits of repeat count) | |
141 | static std::uint8_t constexpr REP_3_6 = 16; | |
142 | ||
143 | // repeat a zero length 3-10 times (3 bits of repeat count) | |
144 | static std::uint8_t constexpr REPZ_3_10 = 17; | |
145 | ||
146 | // repeat a zero length 11-138 times (7 bits of repeat count) | |
147 | static std::uint8_t constexpr REPZ_11_138 = 18; | |
148 | ||
149 | // The three kinds of block type | |
150 | static std::uint8_t constexpr STORED_BLOCK = 0; | |
151 | static std::uint8_t constexpr STATIC_TREES = 1; | |
152 | static std::uint8_t constexpr DYN_TREES = 2; | |
153 | ||
154 | // Maximum value for memLevel in deflateInit2 | |
155 | static std::uint8_t constexpr MAX_MEM_LEVEL = 9; | |
156 | ||
157 | // Default memLevel | |
158 | static std::uint8_t constexpr DEF_MEM_LEVEL = MAX_MEM_LEVEL; | |
159 | ||
160 | /* Note: the deflate() code requires max_lazy >= minMatch and max_chain >= 4 | |
161 | For deflate_fast() (levels <= 3) good is ignored and lazy has a different | |
162 | meaning. | |
163 | */ | |
164 | ||
165 | // maximum heap size | |
166 | static std::uint16_t constexpr HEAP_SIZE = 2 * lCodes + 1; | |
167 | ||
168 | // size of bit buffer in bi_buf | |
169 | static std::uint8_t constexpr Buf_size = 16; | |
170 | ||
171 | // Matches of length 3 are discarded if their distance exceeds kTooFar | |
172 | static std::size_t constexpr kTooFar = 4096; | |
173 | ||
174 | /* Minimum amount of lookahead, except at the end of the input file. | |
175 | See deflate.c for comments about the minMatch+1. | |
176 | */ | |
177 | static std::size_t constexpr kMinLookahead = maxMatch + minMatch+1; | |
178 | ||
179 | /* Number of bytes after end of data in window to initialize in order | |
180 | to avoid memory checker errors from longest match routines | |
181 | */ | |
182 | static std::size_t constexpr kWinInit = maxMatch; | |
183 | ||
184 | // Describes a single value and its code string. | |
185 | struct ct_data | |
186 | { | |
187 | std::uint16_t fc; // frequency count or bit string | |
188 | std::uint16_t dl; // parent node in tree or length of bit string | |
189 | ||
190 | bool | |
191 | operator==(ct_data const& rhs) const | |
192 | { | |
193 | return fc == rhs.fc && dl == rhs.dl; | |
194 | } | |
195 | }; | |
196 | ||
197 | struct static_desc | |
198 | { | |
199 | ct_data const* static_tree;// static tree or NULL | |
200 | std::uint8_t const* extra_bits; // extra bits for each code or NULL | |
201 | std::uint16_t extra_base; // base index for extra_bits | |
202 | std::uint16_t elems; // max number of elements in the tree | |
203 | std::uint8_t max_length; // max bit length for the codes | |
204 | }; | |
205 | ||
206 | struct lut_type | |
207 | { | |
208 | // Number of extra bits for each length code | |
209 | std::uint8_t const extra_lbits[lengthCodes] = { | |
210 | 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 | |
211 | }; | |
212 | ||
213 | // Number of extra bits for each distance code | |
214 | std::uint8_t const extra_dbits[dCodes] = { | |
215 | 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 | |
216 | }; | |
217 | ||
218 | // Number of extra bits for each bit length code | |
219 | std::uint8_t const extra_blbits[blCodes] = { | |
220 | 0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,2,3,7 | |
221 | }; | |
222 | ||
223 | // The lengths of the bit length codes are sent in order | |
224 | // of decreasing probability, to avoid transmitting the | |
225 | // lengths for unused bit length codes. | |
226 | std::uint8_t const bl_order[blCodes] = { | |
227 | 16,17,18,0,8,7,9,6,10,5,11,4,12,3,13,2,14,1,15 | |
228 | }; | |
229 | ||
230 | ct_data ltree[lCodes + 2]; | |
231 | ||
232 | ct_data dtree[dCodes]; | |
233 | ||
234 | // Distance codes. The first 256 values correspond to the distances | |
235 | // 3 .. 258, the last 256 values correspond to the top 8 bits of | |
236 | // the 15 bit distances. | |
237 | std::uint8_t dist_code[distCodeLen]; | |
238 | ||
239 | std::uint8_t length_code[maxMatch-minMatch+1]; | |
240 | ||
241 | std::uint8_t base_length[lengthCodes]; | |
242 | ||
243 | std::uint16_t base_dist[dCodes]; | |
244 | ||
245 | static_desc l_desc = { | |
246 | ltree, extra_lbits, literals+1, lCodes, maxBits | |
247 | }; | |
248 | ||
249 | static_desc d_desc = { | |
250 | dtree, extra_dbits, 0, dCodes, maxBits | |
251 | }; | |
252 | ||
253 | static_desc bl_desc = | |
254 | { | |
255 | nullptr, extra_blbits, 0, blCodes, maxBlBits | |
256 | }; | |
257 | }; | |
258 | ||
259 | struct tree_desc | |
260 | { | |
261 | ct_data *dyn_tree; /* the dynamic tree */ | |
262 | int max_code; /* largest code with non zero frequency */ | |
263 | static_desc const* stat_desc; /* the corresponding static tree */ | |
264 | }; | |
265 | ||
266 | enum block_state | |
267 | { | |
268 | need_more, /* block not completed, need more input or more output */ | |
269 | block_done, /* block flush performed */ | |
270 | finish_started, /* finish started, need only more output at next deflate */ | |
271 | finish_done /* finish done, accept no more input or output */ | |
272 | }; | |
273 | ||
274 | // VFALCO This might not be needed, e.g. for zip/gzip | |
275 | enum StreamStatus | |
276 | { | |
277 | EXTRA_STATE = 69, | |
278 | NAME_STATE = 73, | |
279 | COMMENT_STATE = 91, | |
280 | HCRC_STATE = 103, | |
281 | BUSY_STATE = 113, | |
282 | FINISH_STATE = 666 | |
283 | }; | |
284 | ||
285 | /* A std::uint16_t is an index in the character window. We use short instead of int to | |
286 | * save space in the various tables. IPos is used only for parameter passing. | |
287 | */ | |
288 | using IPos = unsigned; | |
289 | ||
290 | using self = deflate_stream; | |
291 | typedef block_state(self::*compress_func)(z_params& zs, Flush flush); | |
292 | ||
293 | //-------------------------------------------------------------------------- | |
294 | ||
295 | lut_type const& lut_; | |
296 | ||
297 | bool inited_ = false; | |
298 | std::size_t buf_size_; | |
299 | std::unique_ptr<std::uint8_t[]> buf_; | |
300 | ||
301 | int status_; // as the name implies | |
302 | Byte* pending_buf_; // output still pending | |
303 | std::uint32_t | |
304 | pending_buf_size_; // size of pending_buf | |
305 | Byte* pending_out_; // next pending byte to output to the stream | |
306 | uInt pending_; // nb of bytes in the pending buffer | |
307 | boost::optional<Flush> | |
308 | last_flush_; // value of flush param for previous deflate call | |
309 | ||
310 | uInt w_size_; // LZ77 window size (32K by default) | |
311 | uInt w_bits_; // log2(w_size) (8..16) | |
312 | uInt w_mask_; // w_size - 1 | |
313 | ||
314 | /* Sliding window. Input bytes are read into the second half of the window, | |
315 | and move to the first half later to keep a dictionary of at least wSize | |
316 | bytes. With this organization, matches are limited to a distance of | |
317 | wSize-maxMatch bytes, but this ensures that IO is always | |
318 | performed with a length multiple of the block size. Also, it limits | |
319 | the window size to 64K. | |
320 | To do: use the user input buffer as sliding window. | |
321 | */ | |
322 | Byte *window_ = nullptr; | |
323 | ||
324 | /* Actual size of window: 2*wSize, except when the user input buffer | |
325 | is directly used as sliding window. | |
326 | */ | |
327 | std::uint32_t window_size_; | |
328 | ||
329 | /* Link to older string with same hash index. To limit the size of this | |
330 | array to 64K, this link is maintained only for the last 32K strings. | |
331 | An index in this array is thus a window index modulo 32K. | |
332 | */ | |
333 | std::uint16_t* prev_; | |
334 | ||
335 | std::uint16_t* head_; // Heads of the hash chains or 0 | |
336 | ||
337 | uInt ins_h_; // hash index of string to be inserted | |
338 | uInt hash_size_; // number of elements in hash table | |
339 | uInt hash_bits_; // log2(hash_size) | |
340 | uInt hash_mask_; // hash_size-1 | |
341 | ||
342 | /* Number of bits by which ins_h must be shifted at each input | |
343 | step. It must be such that after minMatch steps, | |
344 | the oldest byte no longer takes part in the hash key, that is: | |
345 | hash_shift * minMatch >= hash_bits | |
346 | */ | |
347 | uInt hash_shift_; | |
348 | ||
349 | /* Window position at the beginning of the current output block. | |
350 | Gets negative when the window is moved backwards. | |
351 | */ | |
352 | long block_start_; | |
353 | ||
354 | uInt match_length_; // length of best match | |
355 | IPos prev_match_; // previous match | |
356 | int match_available_; // set if previous match exists | |
357 | uInt strstart_; // start of string to insert | |
358 | uInt match_start_; // start of matching string | |
359 | uInt lookahead_; // number of valid bytes ahead in window | |
360 | ||
361 | /* Length of the best match at previous step. Matches not greater | |
362 | than this are discarded. This is used in the lazy match evaluation. | |
363 | */ | |
364 | uInt prev_length_; | |
365 | ||
366 | /* To speed up deflation, hash chains are never searched beyond | |
367 | this length. A higher limit improves compression ratio but | |
368 | degrades the speed. | |
369 | */ | |
370 | uInt max_chain_length_; | |
371 | ||
372 | /* Attempt to find a better match only when the current match is strictly | |
373 | smaller than this value. This mechanism is used only for compression | |
374 | levels >= 4. | |
375 | ||
376 | OR Insert new strings in the hash table only if the match length is not | |
377 | greater than this length. This saves time but degrades compression. | |
378 | used only for compression levels <= 3. | |
379 | */ | |
380 | uInt max_lazy_match_; | |
381 | ||
382 | int level_; // compression level (1..9) | |
383 | Strategy strategy_; // favor or force Huffman coding | |
384 | ||
385 | // Use a faster search when the previous match is longer than this | |
386 | uInt good_match_; | |
387 | ||
388 | int nice_match_; // Stop searching when current match exceeds this | |
389 | ||
390 | ct_data dyn_ltree_[ | |
391 | HEAP_SIZE]; // literal and length tree | |
392 | ct_data dyn_dtree_[ | |
393 | 2*dCodes+1]; // distance tree | |
394 | ct_data bl_tree_[ | |
395 | 2*blCodes+1]; // Huffman tree for bit lengths | |
396 | ||
397 | tree_desc l_desc_; // desc. for literal tree | |
398 | tree_desc d_desc_; // desc. for distance tree | |
399 | tree_desc bl_desc_; // desc. for bit length tree | |
400 | ||
401 | // number of codes at each bit length for an optimal tree | |
402 | std::uint16_t bl_count_[maxBits+1]; | |
403 | ||
404 | // Index within the heap array of least frequent node in the Huffman tree | |
405 | static std::size_t constexpr kSmallest = 1; | |
406 | ||
407 | /* The sons of heap[n] are heap[2*n] and heap[2*n+1]. | |
408 | heap[0] is not used. The same heap array is used to build all trees. | |
409 | */ | |
410 | ||
411 | int heap_[2*lCodes+1]; // heap used to build the Huffman trees | |
412 | int heap_len_; // number of elements in the heap | |
413 | int heap_max_; // element of largest frequency | |
414 | ||
415 | // Depth of each subtree used as tie breaker for trees of equal frequency | |
416 | std::uint8_t depth_[2*lCodes+1]; | |
417 | ||
418 | std::uint8_t *l_buf_; // buffer for literals or lengths | |
419 | ||
420 | /* Size of match buffer for literals/lengths. | |
421 | There are 4 reasons for limiting lit_bufsize to 64K: | |
422 | - frequencies can be kept in 16 bit counters | |
423 | - if compression is not successful for the first block, all input | |
424 | data is still in the window so we can still emit a stored block even | |
425 | when input comes from standard input. (This can also be done for | |
426 | all blocks if lit_bufsize is not greater than 32K.) | |
427 | - if compression is not successful for a file smaller than 64K, we can | |
428 | even emit a stored file instead of a stored block (saving 5 bytes). | |
429 | This is applicable only for zip (not gzip or zlib). | |
430 | - creating new Huffman trees less frequently may not provide fast | |
431 | adaptation to changes in the input data statistics. (Take for | |
432 | example a binary file with poorly compressible code followed by | |
433 | a highly compressible string table.) Smaller buffer sizes give | |
434 | fast adaptation but have of course the overhead of transmitting | |
435 | trees more frequently. | |
436 | - I can't count above 4 | |
437 | */ | |
438 | uInt lit_bufsize_; | |
439 | uInt last_lit_; // running index in l_buf_ | |
440 | ||
441 | /* Buffer for distances. To simplify the code, d_buf_ and l_buf_ | |
442 | have the same number of elements. To use different lengths, an | |
443 | extra flag array would be necessary. | |
444 | */ | |
445 | std::uint16_t* d_buf_; | |
446 | ||
447 | std::uint32_t opt_len_; // bit length of current block with optimal trees | |
448 | std::uint32_t static_len_; // bit length of current block with static trees | |
449 | uInt matches_; // number of string matches in current block | |
450 | uInt insert_; // bytes at end of window left to insert | |
451 | ||
452 | /* Output buffer. | |
453 | Bits are inserted starting at the bottom (least significant bits). | |
454 | */ | |
455 | std::uint16_t bi_buf_; | |
456 | ||
457 | /* Number of valid bits in bi_buf._ All bits above the last valid | |
458 | bit are always zero. | |
459 | */ | |
460 | int bi_valid_; | |
461 | ||
462 | /* High water mark offset in window for initialized bytes -- bytes | |
463 | above this are set to zero in order to avoid memory check warnings | |
464 | when longest match routines access bytes past the input. This is | |
465 | then updated to the new high water mark. | |
466 | */ | |
467 | std::uint32_t high_water_; | |
468 | ||
469 | //-------------------------------------------------------------------------- | |
470 | ||
471 | deflate_stream() | |
472 | : lut_(get_lut()) | |
473 | { | |
474 | } | |
475 | ||
476 | /* In order to simplify the code, particularly on 16 bit machines, match | |
477 | distances are limited to MAX_DIST instead of WSIZE. | |
478 | */ | |
479 | std::size_t | |
480 | max_dist() const | |
481 | { | |
482 | return w_size_ - kMinLookahead; | |
483 | } | |
484 | ||
485 | void | |
486 | put_byte(std::uint8_t c) | |
487 | { | |
488 | pending_buf_[pending_++] = c; | |
489 | } | |
490 | ||
491 | void | |
492 | put_short(std::uint16_t w) | |
493 | { | |
494 | put_byte(w & 0xff); | |
495 | put_byte(w >> 8); | |
496 | } | |
497 | ||
498 | /* Send a value on a given number of bits. | |
499 | IN assertion: length <= 16 and value fits in length bits. | |
500 | */ | |
501 | void | |
502 | send_bits(int value, int length) | |
503 | { | |
504 | if(bi_valid_ > (int)Buf_size - length) | |
505 | { | |
506 | bi_buf_ |= (std::uint16_t)value << bi_valid_; | |
507 | put_short(bi_buf_); | |
508 | bi_buf_ = (std::uint16_t)value >> (Buf_size - bi_valid_); | |
509 | bi_valid_ += length - Buf_size; | |
510 | } | |
511 | else | |
512 | { | |
513 | bi_buf_ |= (std::uint16_t)(value) << bi_valid_; | |
514 | bi_valid_ += length; | |
515 | } | |
516 | } | |
517 | ||
518 | // Send a code of the given tree | |
519 | void | |
520 | send_code(int value, ct_data const* tree) | |
521 | { | |
522 | send_bits(tree[value].fc, tree[value].dl); | |
523 | } | |
524 | ||
525 | /* Mapping from a distance to a distance code. dist is the | |
526 | distance - 1 and must not have side effects. _dist_code[256] | |
527 | and _dist_code[257] are never used. | |
528 | */ | |
529 | std::uint8_t | |
530 | d_code(unsigned dist) | |
531 | { | |
532 | if(dist < 256) | |
533 | return lut_.dist_code[dist]; | |
534 | return lut_.dist_code[256+(dist>>7)]; | |
535 | } | |
536 | ||
537 | /* Update a hash value with the given input byte | |
538 | IN assertion: all calls to to update_hash are made with | |
539 | consecutive input characters, so that a running hash | |
540 | key can be computed from the previous key instead of | |
541 | complete recalculation each time. | |
542 | */ | |
543 | void | |
544 | update_hash(uInt& h, std::uint8_t c) | |
545 | { | |
546 | h = ((h << hash_shift_) ^ c) & hash_mask_; | |
547 | } | |
548 | ||
549 | /* Initialize the hash table (avoiding 64K overflow for 16 | |
550 | bit systems). prev[] will be initialized on the fly. | |
551 | */ | |
552 | void | |
553 | clear_hash() | |
554 | { | |
555 | head_[hash_size_-1] = 0; | |
556 | std::memset((Byte *)head_, 0, | |
557 | (unsigned)(hash_size_-1)*sizeof(*head_)); | |
558 | } | |
559 | ||
560 | /* Compares two subtrees, using the tree depth as tie breaker | |
561 | when the subtrees have equal frequency. This minimizes the | |
562 | worst case length. | |
563 | */ | |
564 | bool | |
565 | smaller(ct_data const* tree, int n, int m) | |
566 | { | |
567 | return tree[n].fc < tree[m].fc || | |
568 | (tree[n].fc == tree[m].fc && | |
569 | depth_[n] <= depth_[m]); | |
570 | } | |
571 | ||
572 | /* Insert string str in the dictionary and set match_head to the | |
573 | previous head of the hash chain (the most recent string with | |
574 | same hash key). Return the previous length of the hash chain. | |
575 | If this file is compiled with -DFASTEST, the compression level | |
576 | is forced to 1, and no hash chains are maintained. | |
577 | IN assertion: all calls to to INSERT_STRING are made with | |
578 | consecutive input characters and the first minMatch | |
579 | bytes of str are valid (except for the last minMatch-1 | |
580 | bytes of the input file). | |
581 | */ | |
582 | void | |
583 | insert_string(IPos& hash_head) | |
584 | { | |
585 | update_hash(ins_h_, window_[strstart_ + (minMatch-1)]); | |
586 | hash_head = prev_[strstart_ & w_mask_] = head_[ins_h_]; | |
587 | head_[ins_h_] = (std::uint16_t)strstart_; | |
588 | } | |
589 | ||
590 | //-------------------------------------------------------------------------- | |
591 | ||
592 | /* Values for max_lazy_match, good_match and max_chain_length, depending on | |
593 | * the desired pack level (0..9). The values given below have been tuned to | |
594 | * exclude worst case performance for pathological files. Better values may be | |
595 | * found for specific files. | |
596 | */ | |
597 | struct config | |
598 | { | |
599 | std::uint16_t good_length; /* reduce lazy search above this match length */ | |
600 | std::uint16_t max_lazy; /* do not perform lazy search above this match length */ | |
601 | std::uint16_t nice_length; /* quit search above this match length */ | |
602 | std::uint16_t max_chain; | |
603 | compress_func func; | |
604 | ||
605 | config( | |
606 | std::uint16_t good_length_, | |
607 | std::uint16_t max_lazy_, | |
608 | std::uint16_t nice_length_, | |
609 | std::uint16_t max_chain_, | |
610 | compress_func func_) | |
611 | : good_length(good_length_) | |
612 | , max_lazy(max_lazy_) | |
613 | , nice_length(nice_length_) | |
614 | , max_chain(max_chain_) | |
615 | , func(func_) | |
616 | { | |
617 | } | |
618 | }; | |
619 | ||
620 | static | |
621 | config | |
622 | get_config(std::size_t level) | |
623 | { | |
624 | switch(level) | |
625 | { | |
626 | // good lazy nice chain | |
627 | case 0: return { 0, 0, 0, 0, &self::deflate_stored}; // store only | |
628 | case 1: return { 4, 4, 8, 4, &self::deflate_fast}; // max speed, no lazy matches | |
629 | case 2: return { 4, 5, 16, 8, &self::deflate_fast}; | |
630 | case 3: return { 4, 6, 32, 32, &self::deflate_fast}; | |
631 | case 4: return { 4, 4, 16, 16, &self::deflate_slow}; // lazy matches | |
632 | case 5: return { 8, 16, 32, 32, &self::deflate_slow}; | |
633 | case 6: return { 8, 16, 128, 128, &self::deflate_slow}; | |
634 | case 7: return { 8, 32, 128, 256, &self::deflate_slow}; | |
635 | case 8: return { 32, 128, 258, 1024, &self::deflate_slow}; | |
636 | default: | |
637 | case 9: return { 32, 258, 258, 4096, &self::deflate_slow}; // max compression | |
638 | } | |
639 | } | |
640 | ||
641 | void | |
642 | maybe_init() | |
643 | { | |
644 | if(! inited_) | |
645 | init(); | |
646 | } | |
647 | ||
648 | static | |
649 | unsigned | |
650 | bi_reverse(unsigned code, int len); | |
651 | ||
652 | template<class = void> | |
653 | static | |
654 | void | |
655 | gen_codes(ct_data *tree, int max_code, std::uint16_t *bl_count); | |
656 | ||
657 | template<class = void> | |
658 | static | |
659 | lut_type const& | |
660 | get_lut(); | |
661 | ||
662 | template<class = void> void doReset (int level, int windowBits, int memLevel, Strategy strategy); | |
663 | template<class = void> void doReset (); | |
664 | template<class = void> void doClear (); | |
665 | template<class = void> std::size_t doUpperBound (std::size_t sourceLen) const; | |
666 | template<class = void> void doTune (int good_length, int max_lazy, int nice_length, int max_chain); | |
667 | template<class = void> void doParams (z_params& zs, int level, Strategy strategy, error_code& ec); | |
668 | template<class = void> void doWrite (z_params& zs, Flush flush, error_code& ec); | |
669 | template<class = void> void doDictionary (Byte const* dict, uInt dictLength, error_code& ec); | |
670 | template<class = void> void doPrime (int bits, int value, error_code& ec); | |
671 | template<class = void> void doPending (unsigned* value, int* bits); | |
672 | ||
673 | template<class = void> void init (); | |
674 | template<class = void> void lm_init (); | |
675 | template<class = void> void init_block (); | |
676 | template<class = void> void pqdownheap (ct_data const* tree, int k); | |
677 | template<class = void> void pqremove (ct_data const* tree, int& top); | |
678 | template<class = void> void gen_bitlen (tree_desc *desc); | |
679 | template<class = void> void build_tree (tree_desc *desc); | |
680 | template<class = void> void scan_tree (ct_data *tree, int max_code); | |
681 | template<class = void> void send_tree (ct_data *tree, int max_code); | |
682 | template<class = void> int build_bl_tree (); | |
683 | template<class = void> void send_all_trees (int lcodes, int dcodes, int blcodes); | |
684 | template<class = void> void compress_block (ct_data const* ltree, ct_data const* dtree); | |
685 | template<class = void> int detect_data_type (); | |
686 | template<class = void> void bi_windup (); | |
687 | template<class = void> void bi_flush (); | |
688 | template<class = void> void copy_block (char *buf, unsigned len, int header); | |
689 | ||
690 | template<class = void> void tr_init (); | |
691 | template<class = void> void tr_align (); | |
692 | template<class = void> void tr_flush_bits (); | |
693 | template<class = void> void tr_stored_block (char *bu, std::uint32_t stored_len, int last); | |
694 | template<class = void> void tr_tally_dist (std::uint16_t dist, std::uint8_t len, bool& flush); | |
695 | template<class = void> void tr_tally_lit (std::uint8_t c, bool& flush); | |
696 | ||
697 | template<class = void> void tr_flush_block (z_params& zs, char *buf, std::uint32_t stored_len, int last); | |
698 | template<class = void> void fill_window (z_params& zs); | |
699 | template<class = void> void flush_pending (z_params& zs); | |
700 | template<class = void> void flush_block (z_params& zs, bool last); | |
701 | template<class = void> int read_buf (z_params& zs, Byte *buf, unsigned size); | |
702 | template<class = void> uInt longest_match (IPos cur_match); | |
703 | ||
704 | template<class = void> block_state f_stored (z_params& zs, Flush flush); | |
705 | template<class = void> block_state f_fast (z_params& zs, Flush flush); | |
706 | template<class = void> block_state f_slow (z_params& zs, Flush flush); | |
707 | template<class = void> block_state f_rle (z_params& zs, Flush flush); | |
708 | template<class = void> block_state f_huff (z_params& zs, Flush flush); | |
709 | ||
710 | block_state | |
711 | deflate_stored(z_params& zs, Flush flush) | |
712 | { | |
713 | return f_stored(zs, flush); | |
714 | } | |
715 | ||
716 | block_state | |
717 | deflate_fast(z_params& zs, Flush flush) | |
718 | { | |
719 | return f_fast(zs, flush); | |
720 | } | |
721 | ||
722 | block_state | |
723 | deflate_slow(z_params& zs, Flush flush) | |
724 | { | |
725 | return f_slow(zs, flush); | |
726 | } | |
727 | ||
728 | block_state | |
729 | deflate_rle(z_params& zs, Flush flush) | |
730 | { | |
731 | return f_rle(zs, flush); | |
732 | } | |
733 | ||
734 | block_state | |
735 | deflate_huff(z_params& zs, Flush flush) | |
736 | { | |
737 | return f_huff(zs, flush); | |
738 | } | |
739 | }; | |
740 | ||
741 | //-------------------------------------------------------------------------- | |
742 | ||
743 | // Reverse the first len bits of a code | |
744 | inline | |
745 | unsigned | |
746 | deflate_stream:: | |
747 | bi_reverse(unsigned code, int len) | |
748 | { | |
749 | unsigned res = 0; | |
750 | do | |
751 | { | |
752 | res |= code & 1; | |
753 | code >>= 1; | |
754 | res <<= 1; | |
755 | } | |
756 | while(--len > 0); | |
757 | return res >> 1; | |
758 | } | |
759 | ||
760 | /* Generate the codes for a given tree and bit counts (which need not be optimal). | |
761 | IN assertion: the array bl_count contains the bit length statistics for | |
762 | the given tree and the field len is set for all tree elements. | |
763 | OUT assertion: the field code is set for all tree elements of non | |
764 | zero code length. | |
765 | */ | |
766 | template<class> | |
767 | void | |
768 | deflate_stream:: | |
769 | gen_codes(ct_data *tree, int max_code, std::uint16_t *bl_count) | |
770 | { | |
771 | std::uint16_t next_code[maxBits+1]; /* next code value for each bit length */ | |
772 | std::uint16_t code = 0; /* running code value */ | |
773 | int bits; /* bit index */ | |
774 | int n; /* code index */ | |
775 | ||
776 | // The distribution counts are first used to | |
777 | // generate the code values without bit reversal. | |
778 | for(bits = 1; bits <= maxBits; bits++) | |
779 | { | |
780 | code = (code + bl_count[bits-1]) << 1; | |
781 | next_code[bits] = code; | |
782 | } | |
783 | // Check that the bit counts in bl_count are consistent. | |
784 | // The last code must be all ones. | |
785 | BOOST_ASSERT(code + bl_count[maxBits]-1 == (1<<maxBits)-1); | |
786 | for(n = 0; n <= max_code; n++) | |
787 | { | |
788 | int len = tree[n].dl; | |
789 | if(len == 0) | |
790 | continue; | |
791 | tree[n].fc = bi_reverse(next_code[len]++, len); | |
792 | } | |
793 | } | |
794 | ||
795 | template<class> | |
796 | auto | |
797 | deflate_stream::get_lut() -> | |
798 | lut_type const& | |
799 | { | |
800 | struct init | |
801 | { | |
802 | lut_type tables; | |
803 | ||
804 | init() | |
805 | { | |
806 | // number of codes at each bit length for an optimal tree | |
807 | //std::uint16_t bl_count[maxBits+1]; | |
808 | ||
809 | // Initialize the mapping length (0..255) -> length code (0..28) | |
810 | int length = 0; | |
811 | for(std::uint8_t code = 0; code < lengthCodes-1; ++code) | |
812 | { | |
813 | tables.base_length[code] = length; | |
814 | auto const run = 1U << tables.extra_lbits[code]; | |
815 | for(unsigned n = 0; n < run; ++n) | |
816 | tables.length_code[length++] = code; | |
817 | } | |
818 | BOOST_ASSERT(length == 256); | |
819 | // Note that the length 255 (match length 258) can be represented | |
820 | // in two different ways: code 284 + 5 bits or code 285, so we | |
821 | // overwrite length_code[255] to use the best encoding: | |
822 | tables.length_code[255] = lengthCodes-1; | |
823 | ||
824 | // Initialize the mapping dist (0..32K) -> dist code (0..29) | |
825 | { | |
826 | std::uint8_t code; | |
827 | std::uint16_t dist = 0; | |
828 | for(code = 0; code < 16; code++) | |
829 | { | |
830 | tables.base_dist[code] = dist; | |
831 | auto const run = 1U << tables.extra_dbits[code]; | |
832 | for(unsigned n = 0; n < run; ++n) | |
833 | tables.dist_code[dist++] = code; | |
834 | } | |
835 | BOOST_ASSERT(dist == 256); | |
836 | // from now on, all distances are divided by 128 | |
837 | dist >>= 7; | |
838 | for(; code < dCodes; ++code) | |
839 | { | |
840 | tables.base_dist[code] = dist << 7; | |
841 | auto const run = 1U << (tables.extra_dbits[code]-7); | |
842 | for(std::size_t n = 0; n < run; ++n) | |
843 | tables.dist_code[256 + dist++] = code; | |
844 | } | |
845 | BOOST_ASSERT(dist == 256); | |
846 | } | |
847 | ||
848 | // Construct the codes of the static literal tree | |
849 | std::uint16_t bl_count[maxBits+1]; | |
850 | std::memset(bl_count, 0, sizeof(bl_count)); | |
851 | unsigned n = 0; | |
852 | while (n <= 143) | |
853 | tables.ltree[n++].dl = 8; | |
854 | bl_count[8] += 144; | |
855 | while (n <= 255) | |
856 | tables.ltree[n++].dl = 9; | |
857 | bl_count[9] += 112; | |
858 | while (n <= 279) | |
859 | tables.ltree[n++].dl = 7; | |
860 | bl_count[7] += 24; | |
861 | while (n <= 287) | |
862 | tables.ltree[n++].dl = 8; | |
863 | bl_count[8] += 8; | |
864 | // Codes 286 and 287 do not exist, but we must include them in the tree | |
865 | // construction to get a canonical Huffman tree (longest code all ones) | |
866 | gen_codes(tables.ltree, lCodes+1, bl_count); | |
867 | ||
868 | for(n = 0; n < dCodes; ++n) | |
869 | { | |
870 | tables.dtree[n].dl = 5; | |
871 | tables.dtree[n].fc = | |
872 | static_cast<std::uint16_t>(bi_reverse(n, 5)); | |
873 | } | |
874 | } | |
875 | }; | |
876 | static init const data; | |
877 | return data.tables; | |
878 | } | |
879 | ||
880 | template<class> | |
881 | void | |
882 | deflate_stream:: | |
883 | doReset( | |
884 | int level, | |
885 | int windowBits, | |
886 | int memLevel, | |
887 | Strategy strategy) | |
888 | { | |
889 | if(level == Z_DEFAULT_COMPRESSION) | |
890 | level = 6; | |
891 | ||
892 | // VFALCO What do we do about this? | |
893 | // until 256-byte window bug fixed | |
894 | if(windowBits == 8) | |
895 | windowBits = 9; | |
896 | ||
897 | using beast::detail::make_exception; | |
898 | ||
899 | if(level < 0 || level > 9) | |
900 | throw make_exception<std::invalid_argument>( | |
901 | "invalid level", __FILE__, __LINE__); | |
902 | ||
903 | if(windowBits < 8 || windowBits > 15) | |
904 | throw make_exception<std::invalid_argument>( | |
905 | "invalid windowBits", __FILE__, __LINE__); | |
906 | ||
907 | if(memLevel < 1 || memLevel > MAX_MEM_LEVEL) | |
908 | throw make_exception<std::invalid_argument>( | |
909 | "invalid memLevel", __FILE__, __LINE__); | |
910 | ||
911 | w_bits_ = windowBits; | |
912 | ||
913 | hash_bits_ = memLevel + 7; | |
914 | ||
915 | // 16K elements by default | |
916 | lit_bufsize_ = 1 << (memLevel + 6); | |
917 | ||
918 | level_ = level; | |
919 | strategy_ = strategy; | |
920 | inited_ = false; | |
921 | } | |
922 | ||
923 | template<class> | |
924 | void | |
925 | deflate_stream:: | |
926 | doReset() | |
927 | { | |
928 | inited_ = false; | |
929 | } | |
930 | ||
931 | template<class> | |
932 | void | |
933 | deflate_stream:: | |
934 | doClear() | |
935 | { | |
936 | inited_ = false; | |
937 | buf_.reset(); | |
938 | } | |
939 | ||
940 | template<class> | |
941 | std::size_t | |
942 | deflate_stream:: | |
943 | doUpperBound(std::size_t sourceLen) const | |
944 | { | |
945 | std::size_t complen; | |
946 | std::size_t wraplen; | |
947 | ||
948 | /* conservative upper bound for compressed data */ | |
949 | complen = sourceLen + | |
950 | ((sourceLen + 7) >> 3) + ((sourceLen + 63) >> 6) + 5; | |
951 | ||
952 | /* compute wrapper length */ | |
953 | wraplen = 0; | |
954 | ||
955 | /* if not default parameters, return conservative bound */ | |
956 | if(w_bits_ != 15 || hash_bits_ != 8 + 7) | |
957 | return complen + wraplen; | |
958 | ||
959 | /* default settings: return tight bound for that case */ | |
960 | return sourceLen + (sourceLen >> 12) + (sourceLen >> 14) + | |
961 | (sourceLen >> 25) + 13 - 6 + wraplen; | |
962 | } | |
963 | ||
964 | template<class> | |
965 | void | |
966 | deflate_stream:: | |
967 | doTune( | |
968 | int good_length, | |
969 | int max_lazy, | |
970 | int nice_length, | |
971 | int max_chain) | |
972 | { | |
973 | good_match_ = good_length; | |
974 | nice_match_ = nice_length; | |
975 | max_lazy_match_ = max_lazy; | |
976 | max_chain_length_ = max_chain; | |
977 | } | |
978 | ||
979 | template<class> | |
980 | void | |
981 | deflate_stream:: | |
982 | doParams(z_params& zs, int level, Strategy strategy, error_code& ec) | |
983 | { | |
984 | compress_func func; | |
985 | ||
986 | if(level == Z_DEFAULT_COMPRESSION) | |
987 | level = 6; | |
988 | if(level < 0 || level > 9) | |
989 | { | |
990 | ec = error::stream_error; | |
991 | return; | |
992 | } | |
993 | func = get_config(level_).func; | |
994 | ||
995 | if((strategy != strategy_ || func != get_config(level).func) && | |
996 | zs.total_in != 0) | |
997 | { | |
998 | // Flush the last buffer: | |
999 | doWrite(zs, Flush::block, ec); | |
1000 | if(ec == error::need_buffers && pending_ == 0) | |
1001 | ec = {}; | |
1002 | } | |
1003 | if(level_ != level) | |
1004 | { | |
1005 | level_ = level; | |
1006 | max_lazy_match_ = get_config(level).max_lazy; | |
1007 | good_match_ = get_config(level).good_length; | |
1008 | nice_match_ = get_config(level).nice_length; | |
1009 | max_chain_length_ = get_config(level).max_chain; | |
1010 | } | |
1011 | strategy_ = strategy; | |
1012 | } | |
1013 | ||
1014 | template<class> | |
1015 | void | |
1016 | deflate_stream:: | |
1017 | doWrite(z_params& zs, Flush flush, error_code& ec) | |
1018 | { | |
1019 | maybe_init(); | |
1020 | ||
1021 | if(zs.next_out == 0 || (zs.next_in == 0 && zs.avail_in != 0) || | |
1022 | (status_ == FINISH_STATE && flush != Flush::finish)) | |
1023 | { | |
1024 | ec = error::stream_error; | |
1025 | return; | |
1026 | } | |
1027 | if(zs.avail_out == 0) | |
1028 | { | |
1029 | ec = error::need_buffers; | |
1030 | return; | |
1031 | } | |
1032 | ||
1033 | // value of flush param for previous deflate call | |
1034 | boost::optional<Flush> old_flush = last_flush_; | |
1035 | last_flush_ = flush; | |
1036 | ||
1037 | // Flush as much pending output as possible | |
1038 | if(pending_ != 0) | |
1039 | { | |
1040 | flush_pending(zs); | |
1041 | if(zs.avail_out == 0) | |
1042 | { | |
1043 | /* Since avail_out is 0, deflate will be called again with | |
1044 | * more output space, but possibly with both pending and | |
1045 | * avail_in equal to zero. There won't be anything to do, | |
1046 | * but this is not an error situation so make sure we | |
1047 | * return OK instead of BUF_ERROR at next call of deflate: | |
1048 | */ | |
1049 | last_flush_ = boost::none; | |
1050 | return; | |
1051 | } | |
1052 | } | |
1053 | else if(zs.avail_in == 0 && flush <= old_flush && | |
1054 | flush != Flush::finish) | |
1055 | { | |
1056 | /* Make sure there is something to do and avoid duplicate consecutive | |
1057 | * flushes. For repeated and useless calls with Flush::finish, we keep | |
1058 | * returning Z_STREAM_END instead of Z_BUF_ERROR. | |
1059 | */ | |
1060 | ec = error::need_buffers; | |
1061 | return; | |
1062 | } | |
1063 | ||
1064 | // User must not provide more input after the first FINISH: | |
1065 | if(status_ == FINISH_STATE && zs.avail_in != 0) | |
1066 | { | |
1067 | ec = error::need_buffers; | |
1068 | return; | |
1069 | } | |
1070 | ||
1071 | /* Start a new block or continue the current one. | |
1072 | */ | |
1073 | if(zs.avail_in != 0 || lookahead_ != 0 || | |
1074 | (flush != Flush::none && status_ != FINISH_STATE)) | |
1075 | { | |
1076 | block_state bstate; | |
1077 | ||
1078 | switch(strategy_) | |
1079 | { | |
1080 | case Strategy::huffman: | |
1081 | bstate = deflate_huff(zs, flush); | |
1082 | break; | |
1083 | case Strategy::rle: | |
1084 | bstate = deflate_rle(zs, flush); | |
1085 | break; | |
1086 | default: | |
1087 | { | |
1088 | bstate = (this->*(get_config(level_).func))(zs, flush); | |
1089 | break; | |
1090 | } | |
1091 | } | |
1092 | ||
1093 | if(bstate == finish_started || bstate == finish_done) | |
1094 | { | |
1095 | status_ = FINISH_STATE; | |
1096 | } | |
1097 | if(bstate == need_more || bstate == finish_started) | |
1098 | { | |
1099 | if(zs.avail_out == 0) | |
1100 | { | |
1101 | last_flush_ = boost::none; /* avoid BUF_ERROR next call, see above */ | |
1102 | } | |
1103 | return; | |
1104 | /* If flush != Flush::none && avail_out == 0, the next call | |
1105 | of deflate should use the same flush parameter to make sure | |
1106 | that the flush is complete. So we don't have to output an | |
1107 | empty block here, this will be done at next call. This also | |
1108 | ensures that for a very small output buffer, we emit at most | |
1109 | one empty block. | |
1110 | */ | |
1111 | } | |
1112 | if(bstate == block_done) | |
1113 | { | |
1114 | if(flush == Flush::partial) | |
1115 | { | |
1116 | tr_align(); | |
1117 | } | |
1118 | else if(flush != Flush::block) | |
1119 | { | |
1120 | /* FULL_FLUSH or SYNC_FLUSH */ | |
1121 | tr_stored_block((char*)0, 0L, 0); | |
1122 | /* For a full flush, this empty block will be recognized | |
1123 | * as a special marker by inflate_sync(). | |
1124 | */ | |
1125 | if(flush == Flush::full) | |
1126 | { | |
1127 | clear_hash(); // forget history | |
1128 | if(lookahead_ == 0) | |
1129 | { | |
1130 | strstart_ = 0; | |
1131 | block_start_ = 0L; | |
1132 | insert_ = 0; | |
1133 | } | |
1134 | } | |
1135 | } | |
1136 | flush_pending(zs); | |
1137 | if(zs.avail_out == 0) | |
1138 | { | |
1139 | last_flush_ = boost::none; /* avoid BUF_ERROR at next call, see above */ | |
1140 | return; | |
1141 | } | |
1142 | } | |
1143 | } | |
1144 | ||
1145 | if(flush == Flush::finish) | |
1146 | { | |
1147 | ec = error::end_of_stream; | |
1148 | return; | |
1149 | } | |
1150 | } | |
1151 | ||
1152 | // VFALCO Warning: untested | |
1153 | template<class> | |
1154 | void | |
1155 | deflate_stream:: | |
1156 | doDictionary(Byte const* dict, uInt dictLength, error_code& ec) | |
1157 | { | |
1158 | if(lookahead_) | |
1159 | { | |
1160 | ec = error::stream_error; | |
1161 | return; | |
1162 | } | |
1163 | ||
1164 | maybe_init(); | |
1165 | ||
1166 | /* if dict would fill window, just replace the history */ | |
1167 | if(dictLength >= w_size_) | |
1168 | { | |
1169 | clear_hash(); | |
1170 | strstart_ = 0; | |
1171 | block_start_ = 0L; | |
1172 | insert_ = 0; | |
1173 | dict += dictLength - w_size_; /* use the tail */ | |
1174 | dictLength = w_size_; | |
1175 | } | |
1176 | ||
1177 | /* insert dict into window and hash */ | |
1178 | z_params zs; | |
1179 | zs.avail_in = dictLength; | |
1180 | zs.next_in = (const Byte *)dict; | |
1181 | zs.avail_out = 0; | |
1182 | zs.next_out = 0; | |
1183 | fill_window(zs); | |
1184 | while(lookahead_ >= minMatch) | |
1185 | { | |
1186 | uInt str = strstart_; | |
1187 | uInt n = lookahead_ - (minMatch-1); | |
1188 | do | |
1189 | { | |
1190 | update_hash(ins_h_, window_[str + minMatch-1]); | |
1191 | prev_[str & w_mask_] = head_[ins_h_]; | |
1192 | head_[ins_h_] = (std::uint16_t)str; | |
1193 | str++; | |
1194 | } | |
1195 | while(--n); | |
1196 | strstart_ = str; | |
1197 | lookahead_ = minMatch-1; | |
1198 | fill_window(zs); | |
1199 | } | |
1200 | strstart_ += lookahead_; | |
1201 | block_start_ = (long)strstart_; | |
1202 | insert_ = lookahead_; | |
1203 | lookahead_ = 0; | |
1204 | match_length_ = prev_length_ = minMatch-1; | |
1205 | match_available_ = 0; | |
1206 | } | |
1207 | ||
1208 | template<class> | |
1209 | void | |
1210 | deflate_stream:: | |
1211 | doPrime(int bits, int value, error_code& ec) | |
1212 | { | |
1213 | maybe_init(); | |
1214 | ||
1215 | if((Byte *)(d_buf_) < pending_out_ + ((Buf_size + 7) >> 3)) | |
1216 | { | |
1217 | ec = error::need_buffers; | |
1218 | return; | |
1219 | } | |
1220 | ||
1221 | do | |
1222 | { | |
1223 | int put = Buf_size - bi_valid_; | |
1224 | if(put > bits) | |
1225 | put = bits; | |
1226 | bi_buf_ |= (std::uint16_t)((value & ((1 << put) - 1)) << bi_valid_); | |
1227 | bi_valid_ += put; | |
1228 | tr_flush_bits(); | |
1229 | value >>= put; | |
1230 | bits -= put; | |
1231 | } | |
1232 | while(bits); | |
1233 | } | |
1234 | ||
1235 | template<class> | |
1236 | void | |
1237 | deflate_stream:: | |
1238 | doPending(unsigned* value, int* bits) | |
1239 | { | |
1240 | if(value != 0) | |
1241 | *value = pending_; | |
1242 | if(bits != 0) | |
1243 | *bits = bi_valid_; | |
1244 | } | |
1245 | ||
1246 | //-------------------------------------------------------------------------- | |
1247 | ||
1248 | // Do lazy initialization | |
1249 | template<class> | |
1250 | void | |
1251 | deflate_stream:: | |
1252 | init() | |
1253 | { | |
1254 | // Caller must set these: | |
1255 | // w_bits_ | |
1256 | // hash_bits_ | |
1257 | // lit_bufsize_ | |
1258 | // level_ | |
1259 | // strategy_ | |
1260 | ||
1261 | w_size_ = 1 << w_bits_; | |
1262 | w_mask_ = w_size_ - 1; | |
1263 | ||
1264 | hash_size_ = 1 << hash_bits_; | |
1265 | hash_mask_ = hash_size_ - 1; | |
1266 | hash_shift_ = ((hash_bits_+minMatch-1)/minMatch); | |
1267 | ||
1268 | auto const nwindow = w_size_ * 2*sizeof(Byte); | |
1269 | auto const nprev = w_size_ * sizeof(std::uint16_t); | |
1270 | auto const nhead = hash_size_ * sizeof(std::uint16_t); | |
1271 | auto const noverlay = lit_bufsize_ * (sizeof(std::uint16_t)+2); | |
1272 | auto const needed = nwindow + nprev + nhead + noverlay; | |
1273 | ||
1274 | if(! buf_ || buf_size_ != needed) | |
1275 | { | |
1276 | buf_.reset(new std::uint8_t[needed]); | |
1277 | buf_size_ = needed; | |
1278 | } | |
1279 | ||
1280 | window_ = reinterpret_cast<Byte*>(buf_.get()); | |
1281 | prev_ = reinterpret_cast<std::uint16_t*>(buf_.get() + nwindow); | |
1282 | head_ = reinterpret_cast<std::uint16_t*>(buf_.get() + nwindow + nprev); | |
1283 | ||
1284 | /* We overlay pending_buf_ and d_buf_ + l_buf_. This works | |
1285 | since the average output size for(length, distance) | |
1286 | codes is <= 24 bits. | |
1287 | */ | |
1288 | auto overlay = reinterpret_cast<std::uint16_t*>( | |
1289 | buf_.get() + nwindow + nprev + nhead); | |
1290 | ||
1291 | // nothing written to window_ yet | |
1292 | high_water_ = 0; | |
1293 | ||
1294 | pending_buf_ = | |
1295 | reinterpret_cast<std::uint8_t*>(overlay); | |
1296 | pending_buf_size_ = | |
1297 | static_cast<std::uint32_t>(lit_bufsize_) * | |
1298 | (sizeof(std::uint16_t) + 2L); | |
1299 | ||
1300 | d_buf_ = overlay + lit_bufsize_ / sizeof(std::uint16_t); | |
1301 | l_buf_ = pending_buf_ + (1 + sizeof(std::uint16_t)) * lit_bufsize_; | |
1302 | ||
1303 | pending_ = 0; | |
1304 | pending_out_ = pending_buf_; | |
1305 | ||
1306 | status_ = BUSY_STATE; | |
1307 | last_flush_ = Flush::none; | |
1308 | ||
1309 | tr_init(); | |
1310 | lm_init(); | |
1311 | ||
1312 | inited_ = true; | |
1313 | } | |
1314 | ||
1315 | /* Initialize the "longest match" routines for a new zlib stream | |
1316 | */ | |
1317 | template<class> | |
1318 | void | |
1319 | deflate_stream:: | |
1320 | lm_init() | |
1321 | { | |
1322 | window_size_ = (std::uint32_t)2L*w_size_; | |
1323 | ||
1324 | clear_hash(); | |
1325 | ||
1326 | /* Set the default configuration parameters: | |
1327 | */ | |
1328 | // VFALCO TODO just copy the config struct | |
1329 | max_lazy_match_ = get_config(level_).max_lazy; | |
1330 | good_match_ = get_config(level_).good_length; | |
1331 | nice_match_ = get_config(level_).nice_length; | |
1332 | max_chain_length_ = get_config(level_).max_chain; | |
1333 | ||
1334 | strstart_ = 0; | |
1335 | block_start_ = 0L; | |
1336 | lookahead_ = 0; | |
1337 | insert_ = 0; | |
1338 | match_length_ = prev_length_ = minMatch-1; | |
1339 | match_available_ = 0; | |
1340 | ins_h_ = 0; | |
1341 | } | |
1342 | ||
1343 | // Initialize a new block. | |
1344 | // | |
1345 | template<class> | |
1346 | void | |
1347 | deflate_stream:: | |
1348 | init_block() | |
1349 | { | |
1350 | for(int n = 0; n < lCodes; n++) | |
1351 | dyn_ltree_[n].fc = 0; | |
1352 | for(int n = 0; n < dCodes; n++) | |
1353 | dyn_dtree_[n].fc = 0; | |
1354 | for(int n = 0; n < blCodes; n++) | |
1355 | bl_tree_[n].fc = 0; | |
1356 | dyn_ltree_[END_BLOCK].fc = 1; | |
1357 | opt_len_ = 0L; | |
1358 | static_len_ = 0L; | |
1359 | last_lit_ = 0; | |
1360 | matches_ = 0; | |
1361 | } | |
1362 | ||
1363 | /* Restore the heap property by moving down the tree starting at node k, | |
1364 | exchanging a node with the smallest of its two sons if necessary, | |
1365 | stopping when the heap property is re-established (each father smaller | |
1366 | than its two sons). | |
1367 | */ | |
1368 | template<class> | |
1369 | void | |
1370 | deflate_stream:: | |
1371 | pqdownheap( | |
1372 | ct_data const* tree, // the tree to restore | |
1373 | int k) // node to move down | |
1374 | { | |
1375 | int v = heap_[k]; | |
1376 | int j = k << 1; // left son of k | |
1377 | while(j <= heap_len_) | |
1378 | { | |
1379 | // Set j to the smallest of the two sons: | |
1380 | if(j < heap_len_ && | |
1381 | smaller(tree, heap_[j+1], heap_[j])) | |
1382 | j++; | |
1383 | // Exit if v is smaller than both sons | |
1384 | if(smaller(tree, v, heap_[j])) | |
1385 | break; | |
1386 | ||
1387 | // Exchange v with the smallest son | |
1388 | heap_[k] = heap_[j]; | |
1389 | k = j; | |
1390 | ||
1391 | // And continue down the tree, | |
1392 | // setting j to the left son of k | |
1393 | j <<= 1; | |
1394 | } | |
1395 | heap_[k] = v; | |
1396 | } | |
1397 | ||
1398 | /* Remove the smallest element from the heap and recreate the heap | |
1399 | with one less element. Updates heap and heap_len. | |
1400 | */ | |
1401 | template<class> | |
1402 | inline | |
1403 | void | |
1404 | deflate_stream:: | |
1405 | pqremove(ct_data const* tree, int& top) | |
1406 | { | |
1407 | top = heap_[kSmallest]; | |
1408 | heap_[kSmallest] = heap_[heap_len_--]; | |
1409 | pqdownheap(tree, kSmallest); | |
1410 | } | |
1411 | ||
1412 | /* Compute the optimal bit lengths for a tree and update the total bit length | |
1413 | for the current block. | |
1414 | IN assertion: the fields freq and dad are set, heap[heap_max] and | |
1415 | above are the tree nodes sorted by increasing frequency. | |
1416 | OUT assertions: the field len is set to the optimal bit length, the | |
1417 | array bl_count contains the frequencies for each bit length. | |
1418 | The length opt_len is updated; static_len is also updated if stree is | |
1419 | not null. | |
1420 | */ | |
1421 | template<class> | |
1422 | void | |
1423 | deflate_stream:: | |
1424 | gen_bitlen(tree_desc *desc) | |
1425 | { | |
1426 | ct_data *tree = desc->dyn_tree; | |
1427 | int max_code = desc->max_code; | |
1428 | ct_data const* stree = desc->stat_desc->static_tree; | |
1429 | std::uint8_t const *extra = desc->stat_desc->extra_bits; | |
1430 | int base = desc->stat_desc->extra_base; | |
1431 | int max_length = desc->stat_desc->max_length; | |
1432 | int h; // heap index | |
1433 | int n, m; // iterate over the tree elements | |
1434 | int bits; // bit length | |
1435 | int xbits; // extra bits | |
1436 | std::uint16_t f; // frequency | |
1437 | int overflow = 0; // number of elements with bit length too large | |
1438 | ||
1439 | std::fill(&bl_count_[0], &bl_count_[maxBits+1], 0); | |
1440 | ||
1441 | /* In a first pass, compute the optimal bit lengths (which may | |
1442 | * overflow in the case of the bit length tree). | |
1443 | */ | |
1444 | tree[heap_[heap_max_]].dl = 0; // root of the heap | |
1445 | ||
1446 | for(h = heap_max_+1; h < HEAP_SIZE; h++) { | |
1447 | n = heap_[h]; | |
1448 | bits = tree[tree[n].dl].dl + 1; | |
1449 | if(bits > max_length) bits = max_length, overflow++; | |
1450 | // We overwrite tree[n].dl which is no longer needed | |
1451 | tree[n].dl = (std::uint16_t)bits; | |
1452 | ||
1453 | if(n > max_code) | |
1454 | continue; // not a leaf node | |
1455 | ||
1456 | bl_count_[bits]++; | |
1457 | xbits = 0; | |
1458 | if(n >= base) | |
1459 | xbits = extra[n-base]; | |
1460 | f = tree[n].fc; | |
1461 | opt_len_ += (std::uint32_t)f * (bits + xbits); | |
1462 | if(stree) | |
1463 | static_len_ += (std::uint32_t)f * (stree[n].dl + xbits); | |
1464 | } | |
1465 | if(overflow == 0) | |
1466 | return; | |
1467 | ||
1468 | // Find the first bit length which could increase: | |
1469 | do | |
1470 | { | |
1471 | bits = max_length-1; | |
1472 | while(bl_count_[bits] == 0) | |
1473 | bits--; | |
1474 | bl_count_[bits]--; // move one leaf down the tree | |
1475 | bl_count_[bits+1] += 2; // move one overflow item as its brother | |
1476 | bl_count_[max_length]--; | |
1477 | /* The brother of the overflow item also moves one step up, | |
1478 | * but this does not affect bl_count[max_length] | |
1479 | */ | |
1480 | overflow -= 2; | |
1481 | } | |
1482 | while(overflow > 0); | |
1483 | ||
1484 | /* Now recompute all bit lengths, scanning in increasing frequency. | |
1485 | * h is still equal to HEAP_SIZE. (It is simpler to reconstruct all | |
1486 | * lengths instead of fixing only the wrong ones. This idea is taken | |
1487 | * from 'ar' written by Haruhiko Okumura.) | |
1488 | */ | |
1489 | for(bits = max_length; bits != 0; bits--) | |
1490 | { | |
1491 | n = bl_count_[bits]; | |
1492 | while(n != 0) | |
1493 | { | |
1494 | m = heap_[--h]; | |
1495 | if(m > max_code) | |
1496 | continue; | |
1497 | if((unsigned) tree[m].dl != (unsigned) bits) | |
1498 | { | |
1499 | opt_len_ += ((long)bits - (long)tree[m].dl) *(long)tree[m].fc; | |
1500 | tree[m].dl = (std::uint16_t)bits; | |
1501 | } | |
1502 | n--; | |
1503 | } | |
1504 | } | |
1505 | } | |
1506 | ||
1507 | /* Construct one Huffman tree and assigns the code bit strings and lengths. | |
1508 | Update the total bit length for the current block. | |
1509 | IN assertion: the field freq is set for all tree elements. | |
1510 | OUT assertions: the fields len and code are set to the optimal bit length | |
1511 | and corresponding code. The length opt_len is updated; static_len is | |
1512 | also updated if stree is not null. The field max_code is set. | |
1513 | */ | |
1514 | template<class> | |
1515 | void | |
1516 | deflate_stream:: | |
1517 | build_tree(tree_desc *desc) | |
1518 | { | |
1519 | ct_data *tree = desc->dyn_tree; | |
1520 | ct_data const* stree = desc->stat_desc->static_tree; | |
1521 | int elems = desc->stat_desc->elems; | |
1522 | int n, m; // iterate over heap elements | |
1523 | int max_code = -1; // largest code with non zero frequency | |
1524 | int node; // new node being created | |
1525 | ||
1526 | /* Construct the initial heap, with least frequent element in | |
1527 | * heap[kSmallest]. The sons of heap[n] are heap[2*n] and heap[2*n+1]. | |
1528 | * heap[0] is not used. | |
1529 | */ | |
1530 | heap_len_ = 0; | |
1531 | heap_max_ = HEAP_SIZE; | |
1532 | ||
1533 | for(n = 0; n < elems; n++) | |
1534 | { | |
1535 | if(tree[n].fc != 0) | |
1536 | { | |
1537 | heap_[++(heap_len_)] = max_code = n; | |
1538 | depth_[n] = 0; | |
1539 | } | |
1540 | else | |
1541 | { | |
1542 | tree[n].dl = 0; | |
1543 | } | |
1544 | } | |
1545 | ||
1546 | /* The pkzip format requires that at least one distance code exists, | |
1547 | * and that at least one bit should be sent even if there is only one | |
1548 | * possible code. So to avoid special checks later on we force at least | |
1549 | * two codes of non zero frequency. | |
1550 | */ | |
1551 | while(heap_len_ < 2) | |
1552 | { | |
1553 | node = heap_[++(heap_len_)] = (max_code < 2 ? ++max_code : 0); | |
1554 | tree[node].fc = 1; | |
1555 | depth_[node] = 0; | |
1556 | opt_len_--; | |
1557 | if(stree) | |
1558 | static_len_ -= stree[node].dl; | |
1559 | // node is 0 or 1 so it does not have extra bits | |
1560 | } | |
1561 | desc->max_code = max_code; | |
1562 | ||
1563 | /* The elements heap[heap_len/2+1 .. heap_len] are leaves of the tree, | |
1564 | * establish sub-heaps of increasing lengths: | |
1565 | */ | |
1566 | for(n = heap_len_/2; n >= 1; n--) | |
1567 | pqdownheap(tree, n); | |
1568 | ||
1569 | /* Construct the Huffman tree by repeatedly combining the least two | |
1570 | * frequent nodes. | |
1571 | */ | |
1572 | node = elems; /* next internal node of the tree */ | |
1573 | do | |
1574 | { | |
1575 | pqremove(tree, n); /* n = node of least frequency */ | |
1576 | m = heap_[kSmallest]; /* m = node of next least frequency */ | |
1577 | ||
1578 | heap_[--(heap_max_)] = n; /* keep the nodes sorted by frequency */ | |
1579 | heap_[--(heap_max_)] = m; | |
1580 | ||
1581 | /* Create a new node father of n and m */ | |
1582 | tree[node].fc = tree[n].fc + tree[m].fc; | |
1583 | depth_[node] = (std::uint8_t)((depth_[n] >= depth_[m] ? | |
1584 | depth_[n] : depth_[m]) + 1); | |
1585 | tree[n].dl = tree[m].dl = (std::uint16_t)node; | |
1586 | /* and insert the new node in the heap */ | |
1587 | heap_[kSmallest] = node++; | |
1588 | pqdownheap(tree, kSmallest); | |
1589 | ||
1590 | } | |
1591 | while(heap_len_ >= 2); | |
1592 | ||
1593 | heap_[--(heap_max_)] = heap_[kSmallest]; | |
1594 | ||
1595 | /* At this point, the fields freq and dad are set. We can now | |
1596 | * generate the bit lengths. | |
1597 | */ | |
1598 | gen_bitlen((tree_desc *)desc); | |
1599 | ||
1600 | /* The field len is now set, we can generate the bit codes */ | |
1601 | gen_codes(tree, max_code, bl_count_); | |
1602 | } | |
1603 | ||
1604 | /* Scan a literal or distance tree to determine the frequencies | |
1605 | of the codes in the bit length tree. | |
1606 | */ | |
1607 | template<class> | |
1608 | void | |
1609 | deflate_stream:: | |
1610 | scan_tree( | |
1611 | ct_data *tree, // the tree to be scanned | |
1612 | int max_code) // and its largest code of non zero frequency | |
1613 | { | |
1614 | int n; // iterates over all tree elements | |
1615 | int prevlen = -1; // last emitted length | |
1616 | int curlen; // length of current code | |
1617 | int nextlen = tree[0].dl; // length of next code | |
1618 | int count = 0; // repeat count of the current code | |
1619 | int max_count = 7; // max repeat count | |
1620 | int min_count = 4; // min repeat count | |
1621 | ||
1622 | if(nextlen == 0) | |
1623 | { | |
1624 | max_count = 138; | |
1625 | min_count = 3; | |
1626 | } | |
1627 | tree[max_code+1].dl = (std::uint16_t)0xffff; // guard | |
1628 | ||
1629 | for(n = 0; n <= max_code; n++) | |
1630 | { | |
1631 | curlen = nextlen; nextlen = tree[n+1].dl; | |
1632 | if(++count < max_count && curlen == nextlen) | |
1633 | { | |
1634 | continue; | |
1635 | } | |
1636 | else if(count < min_count) | |
1637 | { | |
1638 | bl_tree_[curlen].fc += count; | |
1639 | } | |
1640 | else if(curlen != 0) | |
1641 | { | |
1642 | if(curlen != prevlen) bl_tree_[curlen].fc++; | |
1643 | bl_tree_[REP_3_6].fc++; | |
1644 | } | |
1645 | else if(count <= 10) | |
1646 | { | |
1647 | bl_tree_[REPZ_3_10].fc++; | |
1648 | } | |
1649 | else | |
1650 | { | |
1651 | bl_tree_[REPZ_11_138].fc++; | |
1652 | } | |
1653 | count = 0; | |
1654 | prevlen = curlen; | |
1655 | if(nextlen == 0) | |
1656 | { | |
1657 | max_count = 138; | |
1658 | min_count = 3; | |
1659 | } | |
1660 | else if(curlen == nextlen) | |
1661 | { | |
1662 | max_count = 6; | |
1663 | min_count = 3; | |
1664 | } | |
1665 | else | |
1666 | { | |
1667 | max_count = 7; | |
1668 | min_count = 4; | |
1669 | } | |
1670 | } | |
1671 | } | |
1672 | ||
1673 | /* Send a literal or distance tree in compressed form, | |
1674 | using the codes in bl_tree. | |
1675 | */ | |
1676 | template<class> | |
1677 | void | |
1678 | deflate_stream:: | |
1679 | send_tree( | |
1680 | ct_data *tree, // the tree to be scanned | |
1681 | int max_code) // and its largest code of non zero frequency | |
1682 | { | |
1683 | int n; // iterates over all tree elements | |
1684 | int prevlen = -1; // last emitted length | |
1685 | int curlen; // length of current code | |
1686 | int nextlen = tree[0].dl; // length of next code | |
1687 | int count = 0; // repeat count of the current code | |
1688 | int max_count = 7; // max repeat count | |
1689 | int min_count = 4; // min repeat count | |
1690 | ||
1691 | // tree[max_code+1].dl = -1; // guard already set | |
1692 | if(nextlen == 0) | |
1693 | { | |
1694 | max_count = 138; | |
1695 | min_count = 3; | |
1696 | } | |
1697 | ||
1698 | for(n = 0; n <= max_code; n++) | |
1699 | { | |
1700 | curlen = nextlen; | |
1701 | nextlen = tree[n+1].dl; | |
1702 | if(++count < max_count && curlen == nextlen) | |
1703 | { | |
1704 | continue; | |
1705 | } | |
1706 | else if(count < min_count) | |
1707 | { | |
1708 | do | |
1709 | { | |
1710 | send_code(curlen, bl_tree_); | |
1711 | } | |
1712 | while (--count != 0); | |
1713 | } | |
1714 | else if(curlen != 0) | |
1715 | { | |
1716 | if(curlen != prevlen) | |
1717 | { | |
1718 | send_code(curlen, bl_tree_); | |
1719 | count--; | |
1720 | } | |
1721 | BOOST_ASSERT(count >= 3 && count <= 6); | |
1722 | send_code(REP_3_6, bl_tree_); | |
1723 | send_bits(count-3, 2); | |
1724 | } | |
1725 | else if(count <= 10) | |
1726 | { | |
1727 | send_code(REPZ_3_10, bl_tree_); | |
1728 | send_bits(count-3, 3); | |
1729 | } | |
1730 | else | |
1731 | { | |
1732 | send_code(REPZ_11_138, bl_tree_); | |
1733 | send_bits(count-11, 7); | |
1734 | } | |
1735 | count = 0; | |
1736 | prevlen = curlen; | |
1737 | if(nextlen == 0) | |
1738 | { | |
1739 | max_count = 138; | |
1740 | min_count = 3; | |
1741 | } | |
1742 | else if(curlen == nextlen) | |
1743 | { | |
1744 | max_count = 6; | |
1745 | min_count = 3; | |
1746 | } | |
1747 | else | |
1748 | { | |
1749 | max_count = 7; | |
1750 | min_count = 4; | |
1751 | } | |
1752 | } | |
1753 | } | |
1754 | ||
1755 | /* Construct the Huffman tree for the bit lengths and return | |
1756 | the index in bl_order of the last bit length code to send. | |
1757 | */ | |
1758 | template<class> | |
1759 | int | |
1760 | deflate_stream:: | |
1761 | build_bl_tree() | |
1762 | { | |
1763 | int max_blindex; // index of last bit length code of non zero freq | |
1764 | ||
1765 | // Determine the bit length frequencies for literal and distance trees | |
1766 | scan_tree((ct_data *)dyn_ltree_, l_desc_.max_code); | |
1767 | scan_tree((ct_data *)dyn_dtree_, d_desc_.max_code); | |
1768 | ||
1769 | // Build the bit length tree: | |
1770 | build_tree((tree_desc *)(&(bl_desc_))); | |
1771 | /* opt_len now includes the length of the tree representations, except | |
1772 | * the lengths of the bit lengths codes and the 5+5+4 bits for the counts. | |
1773 | */ | |
1774 | ||
1775 | /* Determine the number of bit length codes to send. The pkzip format | |
1776 | * requires that at least 4 bit length codes be sent. (appnote.txt says | |
1777 | * 3 but the actual value used is 4.) | |
1778 | */ | |
1779 | for(max_blindex = blCodes-1; max_blindex >= 3; max_blindex--) | |
1780 | { | |
1781 | if(bl_tree_[lut_.bl_order[max_blindex]].dl != 0) | |
1782 | break; | |
1783 | } | |
1784 | // Update opt_len to include the bit length tree and counts | |
1785 | opt_len_ += 3*(max_blindex+1) + 5+5+4; | |
1786 | return max_blindex; | |
1787 | } | |
1788 | ||
1789 | /* Send the header for a block using dynamic Huffman trees: the counts, | |
1790 | the lengths of the bit length codes, the literal tree and the distance | |
1791 | tree. | |
1792 | IN assertion: lcodes >= 257, dcodes >= 1, blcodes >= 4. | |
1793 | */ | |
1794 | template<class> | |
1795 | void | |
1796 | deflate_stream:: | |
1797 | send_all_trees( | |
1798 | int lcodes, | |
1799 | int dcodes, | |
1800 | int blcodes) // number of codes for each tree | |
1801 | { | |
1802 | int rank; // index in bl_order | |
1803 | ||
1804 | BOOST_ASSERT(lcodes >= 257 && dcodes >= 1 && blcodes >= 4); | |
1805 | BOOST_ASSERT(lcodes <= lCodes && dcodes <= dCodes && blcodes <= blCodes); | |
1806 | send_bits(lcodes-257, 5); // not +255 as stated in appnote.txt | |
1807 | send_bits(dcodes-1, 5); | |
1808 | send_bits(blcodes-4, 4); // not -3 as stated in appnote.txt | |
1809 | for(rank = 0; rank < blcodes; rank++) | |
1810 | send_bits(bl_tree_[lut_.bl_order[rank]].dl, 3); | |
1811 | send_tree((ct_data *)dyn_ltree_, lcodes-1); // literal tree | |
1812 | send_tree((ct_data *)dyn_dtree_, dcodes-1); // distance tree | |
1813 | } | |
1814 | ||
1815 | /* Send the block data compressed using the given Huffman trees | |
1816 | */ | |
1817 | template<class> | |
1818 | void | |
1819 | deflate_stream:: | |
1820 | compress_block( | |
1821 | ct_data const* ltree, // literal tree | |
1822 | ct_data const* dtree) // distance tree | |
1823 | { | |
1824 | unsigned dist; /* distance of matched string */ | |
1825 | int lc; /* match length or unmatched char (if dist == 0) */ | |
1826 | unsigned lx = 0; /* running index in l_buf */ | |
1827 | unsigned code; /* the code to send */ | |
1828 | int extra; /* number of extra bits to send */ | |
1829 | ||
1830 | if(last_lit_ != 0) | |
1831 | { | |
1832 | do | |
1833 | { | |
1834 | dist = d_buf_[lx]; | |
1835 | lc = l_buf_[lx++]; | |
1836 | if(dist == 0) | |
1837 | { | |
1838 | send_code(lc, ltree); /* send a literal byte */ | |
1839 | } | |
1840 | else | |
1841 | { | |
1842 | /* Here, lc is the match length - minMatch */ | |
1843 | code = lut_.length_code[lc]; | |
1844 | send_code(code+literals+1, ltree); /* send the length code */ | |
1845 | extra = lut_.extra_lbits[code]; | |
1846 | if(extra != 0) | |
1847 | { | |
1848 | lc -= lut_.base_length[code]; | |
1849 | send_bits(lc, extra); /* send the extra length bits */ | |
1850 | } | |
1851 | dist--; /* dist is now the match distance - 1 */ | |
1852 | code = d_code(dist); | |
1853 | BOOST_ASSERT(code < dCodes); | |
1854 | ||
1855 | send_code(code, dtree); /* send the distance code */ | |
1856 | extra = lut_.extra_dbits[code]; | |
1857 | if(extra != 0) | |
1858 | { | |
1859 | dist -= lut_.base_dist[code]; | |
1860 | send_bits(dist, extra); /* send the extra distance bits */ | |
1861 | } | |
1862 | } /* literal or match pair ? */ | |
1863 | ||
1864 | /* Check that the overlay between pending_buf and d_buf+l_buf is ok: */ | |
1865 | BOOST_ASSERT((uInt)(pending_) < lit_bufsize_ + 2*lx); | |
1866 | } | |
1867 | while(lx < last_lit_); | |
1868 | } | |
1869 | ||
1870 | send_code(END_BLOCK, ltree); | |
1871 | } | |
1872 | ||
1873 | /* Check if the data type is TEXT or BINARY, using the following algorithm: | |
1874 | - TEXT if the two conditions below are satisfied: | |
1875 | a) There are no non-portable control characters belonging to the | |
1876 | "black list" (0..6, 14..25, 28..31). | |
1877 | b) There is at least one printable character belonging to the | |
1878 | "white list" (9 {TAB}, 10 {LF}, 13 {CR}, 32..255). | |
1879 | - BINARY otherwise. | |
1880 | - The following partially-portable control characters form a | |
1881 | "gray list" that is ignored in this detection algorithm: | |
1882 | (7 {BEL}, 8 {BS}, 11 {VT}, 12 {FF}, 26 {SUB}, 27 {ESC}). | |
1883 | IN assertion: the fields fc of dyn_ltree are set. | |
1884 | */ | |
1885 | template<class> | |
1886 | int | |
1887 | deflate_stream:: | |
1888 | detect_data_type() | |
1889 | { | |
1890 | /* black_mask is the bit mask of black-listed bytes | |
1891 | * set bits 0..6, 14..25, and 28..31 | |
1892 | * 0xf3ffc07f = binary 11110011111111111100000001111111 | |
1893 | */ | |
1894 | unsigned long black_mask = 0xf3ffc07fUL; | |
1895 | int n; | |
1896 | ||
1897 | // Check for non-textual ("black-listed") bytes. | |
1898 | for(n = 0; n <= 31; n++, black_mask >>= 1) | |
1899 | if((black_mask & 1) && (dyn_ltree_[n].fc != 0)) | |
1900 | return Z_BINARY; | |
1901 | ||
1902 | // Check for textual ("white-listed") bytes. */ | |
1903 | if(dyn_ltree_[9].fc != 0 || dyn_ltree_[10].fc != 0 | |
1904 | || dyn_ltree_[13].fc != 0) | |
1905 | return Z_TEXT; | |
1906 | for(n = 32; n < literals; n++) | |
1907 | if(dyn_ltree_[n].fc != 0) | |
1908 | return Z_TEXT; | |
1909 | ||
1910 | /* There are no "black-listed" or "white-listed" bytes: | |
1911 | * this stream either is empty or has tolerated ("gray-listed") bytes only. | |
1912 | */ | |
1913 | return Z_BINARY; | |
1914 | } | |
1915 | ||
1916 | /* Flush the bit buffer and align the output on a byte boundary | |
1917 | */ | |
1918 | template<class> | |
1919 | void | |
1920 | deflate_stream:: | |
1921 | bi_windup() | |
1922 | { | |
1923 | if(bi_valid_ > 8) | |
1924 | put_short(bi_buf_); | |
1925 | else if(bi_valid_ > 0) | |
1926 | put_byte((Byte)bi_buf_); | |
1927 | bi_buf_ = 0; | |
1928 | bi_valid_ = 0; | |
1929 | } | |
1930 | ||
1931 | /* Flush the bit buffer, keeping at most 7 bits in it. | |
1932 | */ | |
1933 | template<class> | |
1934 | void | |
1935 | deflate_stream:: | |
1936 | bi_flush() | |
1937 | { | |
1938 | if(bi_valid_ == 16) | |
1939 | { | |
1940 | put_short(bi_buf_); | |
1941 | bi_buf_ = 0; | |
1942 | bi_valid_ = 0; | |
1943 | } | |
1944 | else if(bi_valid_ >= 8) | |
1945 | { | |
1946 | put_byte((Byte)bi_buf_); | |
1947 | bi_buf_ >>= 8; | |
1948 | bi_valid_ -= 8; | |
1949 | } | |
1950 | } | |
1951 | ||
1952 | /* Copy a stored block, storing first the length and its | |
1953 | one's complement if requested. | |
1954 | */ | |
1955 | template<class> | |
1956 | void | |
1957 | deflate_stream:: | |
1958 | copy_block( | |
1959 | char *buf, // the input data | |
1960 | unsigned len, // its length | |
1961 | int header) // true if block header must be written | |
1962 | { | |
1963 | bi_windup(); // align on byte boundary | |
1964 | ||
1965 | if(header) | |
1966 | { | |
1967 | put_short((std::uint16_t)len); | |
1968 | put_short((std::uint16_t)~len); | |
1969 | } | |
1970 | // VFALCO Use memcpy? | |
1971 | while (len--) | |
1972 | put_byte(*buf++); | |
1973 | } | |
1974 | ||
1975 | //------------------------------------------------------------------------------ | |
1976 | ||
1977 | /* Initialize the tree data structures for a new zlib stream. | |
1978 | */ | |
1979 | template<class> | |
1980 | void | |
1981 | deflate_stream:: | |
1982 | tr_init() | |
1983 | { | |
1984 | l_desc_.dyn_tree = dyn_ltree_; | |
1985 | l_desc_.stat_desc = &lut_.l_desc; | |
1986 | ||
1987 | d_desc_.dyn_tree = dyn_dtree_; | |
1988 | d_desc_.stat_desc = &lut_.d_desc; | |
1989 | ||
1990 | bl_desc_.dyn_tree = bl_tree_; | |
1991 | bl_desc_.stat_desc = &lut_.bl_desc; | |
1992 | ||
1993 | bi_buf_ = 0; | |
1994 | bi_valid_ = 0; | |
1995 | ||
1996 | // Initialize the first block of the first file: | |
1997 | init_block(); | |
1998 | } | |
1999 | ||
2000 | /* Send one empty static block to give enough lookahead for inflate. | |
2001 | This takes 10 bits, of which 7 may remain in the bit buffer. | |
2002 | */ | |
2003 | template<class> | |
2004 | void | |
2005 | deflate_stream:: | |
2006 | tr_align() | |
2007 | { | |
2008 | send_bits(STATIC_TREES<<1, 3); | |
2009 | send_code(END_BLOCK, lut_.ltree); | |
2010 | bi_flush(); | |
2011 | } | |
2012 | ||
2013 | /* Flush the bits in the bit buffer to pending output (leaves at most 7 bits) | |
2014 | */ | |
2015 | template<class> | |
2016 | void | |
2017 | deflate_stream:: | |
2018 | tr_flush_bits() | |
2019 | { | |
2020 | bi_flush(); | |
2021 | } | |
2022 | ||
2023 | /* Send a stored block | |
2024 | */ | |
2025 | template<class> | |
2026 | void | |
2027 | deflate_stream:: | |
2028 | tr_stored_block( | |
2029 | char *buf, // input block | |
2030 | std::uint32_t stored_len, // length of input block | |
2031 | int last) // one if this is the last block for a file | |
2032 | { | |
2033 | send_bits((STORED_BLOCK<<1)+last, 3); // send block type | |
2034 | copy_block(buf, (unsigned)stored_len, 1); // with header | |
2035 | } | |
2036 | ||
2037 | template<class> | |
2038 | inline | |
2039 | void | |
2040 | deflate_stream:: | |
2041 | tr_tally_dist(std::uint16_t dist, std::uint8_t len, bool& flush) | |
2042 | { | |
2043 | d_buf_[last_lit_] = dist; | |
2044 | l_buf_[last_lit_++] = len; | |
2045 | dist--; | |
2046 | dyn_ltree_[lut_.length_code[len]+literals+1].fc++; | |
2047 | dyn_dtree_[d_code(dist)].fc++; | |
2048 | flush = (last_lit_ == lit_bufsize_-1); | |
2049 | } | |
2050 | ||
2051 | template<class> | |
2052 | inline | |
2053 | void | |
2054 | deflate_stream:: | |
2055 | tr_tally_lit(std::uint8_t c, bool& flush) | |
2056 | { | |
2057 | d_buf_[last_lit_] = 0; | |
2058 | l_buf_[last_lit_++] = c; | |
2059 | dyn_ltree_[c].fc++; | |
2060 | flush = (last_lit_ == lit_bufsize_-1); | |
2061 | } | |
2062 | ||
2063 | //------------------------------------------------------------------------------ | |
2064 | ||
2065 | /* Determine the best encoding for the current block: dynamic trees, | |
2066 | static trees or store, and output the encoded block to the zip file. | |
2067 | */ | |
2068 | template<class> | |
2069 | void | |
2070 | deflate_stream:: | |
2071 | tr_flush_block( | |
2072 | z_params& zs, | |
2073 | char *buf, // input block, or NULL if too old | |
2074 | std::uint32_t stored_len, // length of input block | |
2075 | int last) // one if this is the last block for a file | |
2076 | { | |
2077 | std::uint32_t opt_lenb; | |
2078 | std::uint32_t static_lenb; // opt_len and static_len in bytes | |
2079 | int max_blindex = 0; // index of last bit length code of non zero freq | |
2080 | ||
2081 | // Build the Huffman trees unless a stored block is forced | |
2082 | if(level_ > 0) | |
2083 | { | |
2084 | // Check if the file is binary or text | |
2085 | if(zs.data_type == Z_UNKNOWN) | |
2086 | zs.data_type = detect_data_type(); | |
2087 | ||
2088 | // Construct the literal and distance trees | |
2089 | build_tree((tree_desc *)(&(l_desc_))); | |
2090 | ||
2091 | build_tree((tree_desc *)(&(d_desc_))); | |
2092 | /* At this point, opt_len and static_len are the total bit lengths of | |
2093 | * the compressed block data, excluding the tree representations. | |
2094 | */ | |
2095 | ||
2096 | /* Build the bit length tree for the above two trees, and get the index | |
2097 | * in bl_order of the last bit length code to send. | |
2098 | */ | |
2099 | max_blindex = build_bl_tree(); | |
2100 | ||
2101 | /* Determine the best encoding. Compute the block lengths in bytes. */ | |
2102 | opt_lenb = (opt_len_+3+7)>>3; | |
2103 | static_lenb = (static_len_+3+7)>>3; | |
2104 | ||
2105 | if(static_lenb <= opt_lenb) | |
2106 | opt_lenb = static_lenb; | |
2107 | } | |
2108 | else | |
2109 | { | |
2110 | // VFALCO This assertion fails even in the original ZLib, | |
2111 | // happens with strategy == Z_HUFFMAN_ONLY, see: | |
2112 | // https://github.com/madler/zlib/issues/172 | |
2113 | ||
2114 | #if 0 | |
2115 | BOOST_ASSERT(buf); | |
2116 | #endif | |
2117 | opt_lenb = static_lenb = stored_len + 5; // force a stored block | |
2118 | } | |
2119 | ||
2120 | #ifdef FORCE_STORED | |
2121 | if(buf != (char*)0) { /* force stored block */ | |
2122 | #else | |
2123 | if(stored_len+4 <= opt_lenb && buf != (char*)0) { | |
2124 | /* 4: two words for the lengths */ | |
2125 | #endif | |
2126 | /* The test buf != NULL is only necessary if LIT_BUFSIZE > WSIZE. | |
2127 | * Otherwise we can't have processed more than WSIZE input bytes since | |
2128 | * the last block flush, because compression would have been | |
2129 | * successful. If LIT_BUFSIZE <= WSIZE, it is never too late to | |
2130 | * transform a block into a stored block. | |
2131 | */ | |
2132 | tr_stored_block(buf, stored_len, last); | |
2133 | ||
2134 | #ifdef FORCE_STATIC | |
2135 | } | |
2136 | else if(static_lenb >= 0) | |
2137 | { | |
2138 | // force static trees | |
2139 | #else | |
2140 | } | |
2141 | else if(strategy_ == Strategy::fixed || static_lenb == opt_lenb) | |
2142 | { | |
2143 | #endif | |
2144 | send_bits((STATIC_TREES<<1)+last, 3); | |
2145 | compress_block(lut_.ltree, lut_.dtree); | |
2146 | } | |
2147 | else | |
2148 | { | |
2149 | send_bits((DYN_TREES<<1)+last, 3); | |
2150 | send_all_trees(l_desc_.max_code+1, d_desc_.max_code+1, | |
2151 | max_blindex+1); | |
2152 | compress_block((const ct_data *)dyn_ltree_, | |
2153 | (const ct_data *)dyn_dtree_); | |
2154 | } | |
2155 | /* The above check is made mod 2^32, for files larger than 512 MB | |
2156 | * and std::size_t implemented on 32 bits. | |
2157 | */ | |
2158 | init_block(); | |
2159 | ||
2160 | if(last) | |
2161 | bi_windup(); | |
2162 | } | |
2163 | ||
2164 | template<class> | |
2165 | void | |
2166 | deflate_stream:: | |
2167 | fill_window(z_params& zs) | |
2168 | { | |
2169 | unsigned n, m; | |
2170 | unsigned more; // Amount of free space at the end of the window. | |
2171 | std::uint16_t *p; | |
2172 | uInt wsize = w_size_; | |
2173 | ||
2174 | do | |
2175 | { | |
2176 | more = (unsigned)(window_size_ - | |
2177 | (std::uint32_t)lookahead_ -(std::uint32_t)strstart_); | |
2178 | ||
2179 | // VFALCO We don't support systems below 32-bit | |
2180 | #if 0 | |
2181 | // Deal with !@#$% 64K limit: | |
2182 | if(sizeof(int) <= 2) | |
2183 | { | |
2184 | if(more == 0 && strstart_ == 0 && lookahead_ == 0) | |
2185 | { | |
2186 | more = wsize; | |
2187 | } | |
2188 | else if(more == (unsigned)(-1)) | |
2189 | { | |
2190 | /* Very unlikely, but possible on 16 bit machine if | |
2191 | * strstart == 0 && lookahead == 1 (input done a byte at time) | |
2192 | */ | |
2193 | more--; | |
2194 | } | |
2195 | } | |
2196 | #endif | |
2197 | ||
2198 | /* If the window is almost full and there is insufficient lookahead, | |
2199 | move the upper half to the lower one to make room in the upper half. | |
2200 | */ | |
2201 | if(strstart_ >= wsize+max_dist()) | |
2202 | { | |
2203 | std::memcpy(window_, window_+wsize, (unsigned)wsize); | |
2204 | match_start_ -= wsize; | |
2205 | strstart_ -= wsize; // we now have strstart >= max_dist | |
2206 | block_start_ -= (long) wsize; | |
2207 | ||
2208 | /* Slide the hash table (could be avoided with 32 bit values | |
2209 | at the expense of memory usage). We slide even when level == 0 | |
2210 | to keep the hash table consistent if we switch back to level > 0 | |
2211 | later. (Using level 0 permanently is not an optimal usage of | |
2212 | zlib, so we don't care about this pathological case.) | |
2213 | */ | |
2214 | n = hash_size_; | |
2215 | p = &head_[n]; | |
2216 | do | |
2217 | { | |
2218 | m = *--p; | |
2219 | *p = (std::uint16_t)(m >= wsize ? m-wsize : 0); | |
2220 | } | |
2221 | while(--n); | |
2222 | ||
2223 | n = wsize; | |
2224 | p = &prev_[n]; | |
2225 | do | |
2226 | { | |
2227 | m = *--p; | |
2228 | *p = (std::uint16_t)(m >= wsize ? m-wsize : 0); | |
2229 | /* If n is not on any hash chain, prev[n] is garbage but | |
2230 | its value will never be used. | |
2231 | */ | |
2232 | } | |
2233 | while(--n); | |
2234 | more += wsize; | |
2235 | } | |
2236 | if(zs.avail_in == 0) | |
2237 | break; | |
2238 | ||
2239 | /* If there was no sliding: | |
2240 | strstart <= WSIZE+max_dist-1 && lookahead <= kMinLookahead - 1 && | |
2241 | more == window_size - lookahead - strstart | |
2242 | => more >= window_size - (kMinLookahead-1 + WSIZE + max_dist-1) | |
2243 | => more >= window_size - 2*WSIZE + 2 | |
2244 | In the BIG_MEM or MMAP case (not yet supported), | |
2245 | window_size == input_size + kMinLookahead && | |
2246 | strstart + lookahead_ <= input_size => more >= kMinLookahead. | |
2247 | Otherwise, window_size == 2*WSIZE so more >= 2. | |
2248 | If there was sliding, more >= WSIZE. So in all cases, more >= 2. | |
2249 | */ | |
2250 | n = read_buf(zs, window_ + strstart_ + lookahead_, more); | |
2251 | lookahead_ += n; | |
2252 | ||
2253 | // Initialize the hash value now that we have some input: | |
2254 | if(lookahead_ + insert_ >= minMatch) | |
2255 | { | |
2256 | uInt str = strstart_ - insert_; | |
2257 | ins_h_ = window_[str]; | |
2258 | update_hash(ins_h_, window_[str + 1]); | |
2259 | while(insert_) | |
2260 | { | |
2261 | update_hash(ins_h_, window_[str + minMatch-1]); | |
2262 | prev_[str & w_mask_] = head_[ins_h_]; | |
2263 | head_[ins_h_] = (std::uint16_t)str; | |
2264 | str++; | |
2265 | insert_--; | |
2266 | if(lookahead_ + insert_ < minMatch) | |
2267 | break; | |
2268 | } | |
2269 | } | |
2270 | /* If the whole input has less than minMatch bytes, ins_h is garbage, | |
2271 | but this is not important since only literal bytes will be emitted. | |
2272 | */ | |
2273 | } | |
2274 | while(lookahead_ < kMinLookahead && zs.avail_in != 0); | |
2275 | ||
2276 | /* If the kWinInit bytes after the end of the current data have never been | |
2277 | written, then zero those bytes in order to avoid memory check reports of | |
2278 | the use of uninitialized (or uninitialised as Julian writes) bytes by | |
2279 | the longest match routines. Update the high water mark for the next | |
2280 | time through here. kWinInit is set to maxMatch since the longest match | |
2281 | routines allow scanning to strstart + maxMatch, ignoring lookahead. | |
2282 | */ | |
2283 | if(high_water_ < window_size_) | |
2284 | { | |
2285 | std::uint32_t curr = strstart_ + (std::uint32_t)(lookahead_); | |
2286 | std::uint32_t init; | |
2287 | ||
2288 | if(high_water_ < curr) | |
2289 | { | |
2290 | /* Previous high water mark below current data -- zero kWinInit | |
2291 | bytes or up to end of window, whichever is less. | |
2292 | */ | |
2293 | init = window_size_ - curr; | |
2294 | if(init > kWinInit) | |
2295 | init = kWinInit; | |
2296 | std::memset(window_ + curr, 0, (unsigned)init); | |
2297 | high_water_ = curr + init; | |
2298 | } | |
2299 | else if(high_water_ < (std::uint32_t)curr + kWinInit) | |
2300 | { | |
2301 | /* High water mark at or above current data, but below current data | |
2302 | plus kWinInit -- zero out to current data plus kWinInit, or up | |
2303 | to end of window, whichever is less. | |
2304 | */ | |
2305 | init = (std::uint32_t)curr + kWinInit - high_water_; | |
2306 | if(init > window_size_ - high_water_) | |
2307 | init = window_size_ - high_water_; | |
2308 | std::memset(window_ + high_water_, 0, (unsigned)init); | |
2309 | high_water_ += init; | |
2310 | } | |
2311 | } | |
2312 | } | |
2313 | ||
2314 | /* Flush as much pending output as possible. All write() output goes | |
2315 | through this function so some applications may wish to modify it | |
2316 | to avoid allocating a large strm->next_out buffer and copying into it. | |
2317 | (See also read_buf()). | |
2318 | */ | |
2319 | template<class> | |
2320 | void | |
2321 | deflate_stream:: | |
2322 | flush_pending(z_params& zs) | |
2323 | { | |
2324 | tr_flush_bits(); | |
2325 | auto len = clamp(pending_, zs.avail_out); | |
2326 | if(len == 0) | |
2327 | return; | |
2328 | ||
2329 | std::memcpy(zs.next_out, pending_out_, len); | |
2330 | zs.next_out = | |
2331 | static_cast<std::uint8_t*>(zs.next_out) + len; | |
2332 | pending_out_ += len; | |
2333 | zs.total_out += len; | |
2334 | zs.avail_out -= len; | |
2335 | pending_ -= len; | |
2336 | if(pending_ == 0) | |
2337 | pending_out_ = pending_buf_; | |
2338 | } | |
2339 | ||
2340 | /* Flush the current block, with given end-of-file flag. | |
2341 | IN assertion: strstart is set to the end of the current match. | |
2342 | */ | |
2343 | template<class> | |
2344 | inline | |
2345 | void | |
2346 | deflate_stream:: | |
2347 | flush_block(z_params& zs, bool last) | |
2348 | { | |
2349 | tr_flush_block(zs, | |
2350 | (block_start_ >= 0L ? | |
2351 | (char *)&window_[(unsigned)block_start_] : | |
2352 | (char *)0), | |
2353 | (std::uint32_t)((long)strstart_ - block_start_), | |
2354 | last); | |
2355 | block_start_ = strstart_; | |
2356 | flush_pending(zs); | |
2357 | } | |
2358 | ||
2359 | /* Read a new buffer from the current input stream, update the adler32 | |
2360 | and total number of bytes read. All write() input goes through | |
2361 | this function so some applications may wish to modify it to avoid | |
2362 | allocating a large strm->next_in buffer and copying from it. | |
2363 | (See also flush_pending()). | |
2364 | */ | |
2365 | template<class> | |
2366 | int | |
2367 | deflate_stream:: | |
2368 | read_buf(z_params& zs, Byte *buf, unsigned size) | |
2369 | { | |
2370 | auto len = clamp(zs.avail_in, size); | |
2371 | if(len == 0) | |
2372 | return 0; | |
2373 | ||
2374 | zs.avail_in -= len; | |
2375 | ||
2376 | std::memcpy(buf, zs.next_in, len); | |
2377 | zs.next_in = static_cast< | |
2378 | std::uint8_t const*>(zs.next_in) + len; | |
2379 | zs.total_in += len; | |
2380 | return (int)len; | |
2381 | } | |
2382 | ||
2383 | /* Set match_start to the longest match starting at the given string and | |
2384 | return its length. Matches shorter or equal to prev_length are discarded, | |
2385 | in which case the result is equal to prev_length and match_start is | |
2386 | garbage. | |
2387 | IN assertions: cur_match is the head of the hash chain for the current | |
2388 | string (strstart) and its distance is <= max_dist, and prev_length >= 1 | |
2389 | OUT assertion: the match length is not greater than s->lookahead_. | |
2390 | ||
2391 | For 80x86 and 680x0, an optimized version will be provided in match.asm or | |
2392 | match.S. The code will be functionally equivalent. | |
2393 | */ | |
2394 | template<class> | |
2395 | uInt | |
2396 | deflate_stream:: | |
2397 | longest_match(IPos cur_match) | |
2398 | { | |
2399 | unsigned chain_length = max_chain_length_;/* max hash chain length */ | |
2400 | Byte *scan = window_ + strstart_; /* current string */ | |
2401 | Byte *match; /* matched string */ | |
2402 | int len; /* length of current match */ | |
2403 | int best_len = prev_length_; /* best match length so far */ | |
2404 | int nice_match = nice_match_; /* stop if match long enough */ | |
2405 | IPos limit = strstart_ > (IPos)max_dist() ? | |
2406 | strstart_ - (IPos)max_dist() : 0; | |
2407 | /* Stop when cur_match becomes <= limit. To simplify the code, | |
2408 | * we prevent matches with the string of window index 0. | |
2409 | */ | |
2410 | std::uint16_t *prev = prev_; | |
2411 | uInt wmask = w_mask_; | |
2412 | ||
2413 | Byte *strend = window_ + strstart_ + maxMatch; | |
2414 | Byte scan_end1 = scan[best_len-1]; | |
2415 | Byte scan_end = scan[best_len]; | |
2416 | ||
2417 | /* The code is optimized for HASH_BITS >= 8 and maxMatch-2 multiple of 16. | |
2418 | * It is easy to get rid of this optimization if necessary. | |
2419 | */ | |
2420 | BOOST_ASSERT(hash_bits_ >= 8 && maxMatch == 258); | |
2421 | ||
2422 | /* Do not waste too much time if we already have a good match: */ | |
2423 | if(prev_length_ >= good_match_) { | |
2424 | chain_length >>= 2; | |
2425 | } | |
2426 | /* Do not look for matches beyond the end of the input. This is necessary | |
2427 | * to make deflate deterministic. | |
2428 | */ | |
2429 | if((uInt)nice_match > lookahead_) | |
2430 | nice_match = lookahead_; | |
2431 | ||
2432 | BOOST_ASSERT((std::uint32_t)strstart_ <= window_size_-kMinLookahead); | |
2433 | ||
2434 | do { | |
2435 | BOOST_ASSERT(cur_match < strstart_); | |
2436 | match = window_ + cur_match; | |
2437 | ||
2438 | /* Skip to next match if the match length cannot increase | |
2439 | * or if the match length is less than 2. Note that the checks below | |
2440 | * for insufficient lookahead only occur occasionally for performance | |
2441 | * reasons. Therefore uninitialized memory will be accessed, and | |
2442 | * conditional jumps will be made that depend on those values. | |
2443 | * However the length of the match is limited to the lookahead, so | |
2444 | * the output of deflate is not affected by the uninitialized values. | |
2445 | */ | |
2446 | if( match[best_len] != scan_end || | |
2447 | match[best_len-1] != scan_end1 || | |
2448 | *match != *scan || | |
2449 | *++match != scan[1]) | |
2450 | continue; | |
2451 | ||
2452 | /* The check at best_len-1 can be removed because it will be made | |
2453 | * again later. (This heuristic is not always a win.) | |
2454 | * It is not necessary to compare scan[2] and match[2] since they | |
2455 | * are always equal when the other bytes match, given that | |
2456 | * the hash keys are equal and that HASH_BITS >= 8. | |
2457 | */ | |
2458 | scan += 2, match++; | |
2459 | BOOST_ASSERT(*scan == *match); | |
2460 | ||
2461 | /* We check for insufficient lookahead only every 8th comparison; | |
2462 | * the 256th check will be made at strstart+258. | |
2463 | */ | |
2464 | do | |
2465 | { | |
2466 | } | |
2467 | while( *++scan == *++match && *++scan == *++match && | |
2468 | *++scan == *++match && *++scan == *++match && | |
2469 | *++scan == *++match && *++scan == *++match && | |
2470 | *++scan == *++match && *++scan == *++match && | |
2471 | scan < strend); | |
2472 | ||
2473 | BOOST_ASSERT(scan <= window_+(unsigned)(window_size_-1)); | |
2474 | ||
2475 | len = maxMatch - (int)(strend - scan); | |
2476 | scan = strend - maxMatch; | |
2477 | ||
2478 | if(len > best_len) { | |
2479 | match_start_ = cur_match; | |
2480 | best_len = len; | |
2481 | if(len >= nice_match) break; | |
2482 | scan_end1 = scan[best_len-1]; | |
2483 | scan_end = scan[best_len]; | |
2484 | } | |
2485 | } | |
2486 | while((cur_match = prev[cur_match & wmask]) > limit | |
2487 | && --chain_length != 0); | |
2488 | ||
2489 | if((uInt)best_len <= lookahead_) | |
2490 | return (uInt)best_len; | |
2491 | return lookahead_; | |
2492 | } | |
2493 | ||
2494 | //------------------------------------------------------------------------------ | |
2495 | ||
2496 | /* Copy without compression as much as possible from the input stream, return | |
2497 | the current block state. | |
2498 | This function does not insert new strings in the dictionary since | |
2499 | uncompressible data is probably not useful. This function is used | |
2500 | only for the level=0 compression option. | |
2501 | NOTE: this function should be optimized to avoid extra copying from | |
2502 | window to pending_buf. | |
2503 | */ | |
2504 | template<class> | |
2505 | inline | |
2506 | auto | |
2507 | deflate_stream:: | |
2508 | f_stored(z_params& zs, Flush flush) -> | |
2509 | block_state | |
2510 | { | |
2511 | /* Stored blocks are limited to 0xffff bytes, pending_buf is limited | |
2512 | * to pending_buf_size, and each stored block has a 5 byte header: | |
2513 | */ | |
2514 | std::uint32_t max_block_size = 0xffff; | |
2515 | std::uint32_t max_start; | |
2516 | ||
2517 | if(max_block_size > pending_buf_size_ - 5) { | |
2518 | max_block_size = pending_buf_size_ - 5; | |
2519 | } | |
2520 | ||
2521 | /* Copy as much as possible from input to output: */ | |
2522 | for(;;) { | |
2523 | /* Fill the window as much as possible: */ | |
2524 | if(lookahead_ <= 1) { | |
2525 | ||
2526 | BOOST_ASSERT(strstart_ < w_size_+max_dist() || | |
2527 | block_start_ >= (long)w_size_); | |
2528 | ||
2529 | fill_window(zs); | |
2530 | if(lookahead_ == 0 && flush == Flush::none) | |
2531 | return need_more; | |
2532 | ||
2533 | if(lookahead_ == 0) break; /* flush the current block */ | |
2534 | } | |
2535 | BOOST_ASSERT(block_start_ >= 0L); | |
2536 | ||
2537 | strstart_ += lookahead_; | |
2538 | lookahead_ = 0; | |
2539 | ||
2540 | /* Emit a stored block if pending_buf will be full: */ | |
2541 | max_start = block_start_ + max_block_size; | |
2542 | if(strstart_ == 0 || (std::uint32_t)strstart_ >= max_start) { | |
2543 | /* strstart == 0 is possible when wraparound on 16-bit machine */ | |
2544 | lookahead_ = (uInt)(strstart_ - max_start); | |
2545 | strstart_ = (uInt)max_start; | |
2546 | flush_block(zs, false); | |
2547 | if(zs.avail_out == 0) | |
2548 | return need_more; | |
2549 | } | |
2550 | /* Flush if we may have to slide, otherwise block_start may become | |
2551 | * negative and the data will be gone: | |
2552 | */ | |
2553 | if(strstart_ - (uInt)block_start_ >= max_dist()) { | |
2554 | flush_block(zs, false); | |
2555 | if(zs.avail_out == 0) | |
2556 | return need_more; | |
2557 | } | |
2558 | } | |
2559 | insert_ = 0; | |
2560 | if(flush == Flush::finish) | |
2561 | { | |
2562 | flush_block(zs, true); | |
2563 | if(zs.avail_out == 0) | |
2564 | return finish_started; | |
2565 | return finish_done; | |
2566 | } | |
2567 | if((long)strstart_ > block_start_) | |
2568 | { | |
2569 | flush_block(zs, false); | |
2570 | if(zs.avail_out == 0) | |
2571 | return need_more; | |
2572 | } | |
2573 | return block_done; | |
2574 | } | |
2575 | ||
2576 | /* Compress as much as possible from the input stream, return the current | |
2577 | block state. | |
2578 | This function does not perform lazy evaluation of matches and inserts | |
2579 | new strings in the dictionary only for unmatched strings or for short | |
2580 | matches. It is used only for the fast compression options. | |
2581 | */ | |
2582 | template<class> | |
2583 | inline | |
2584 | auto | |
2585 | deflate_stream:: | |
2586 | f_fast(z_params& zs, Flush flush) -> | |
2587 | block_state | |
2588 | { | |
2589 | IPos hash_head; /* head of the hash chain */ | |
2590 | bool bflush; /* set if current block must be flushed */ | |
2591 | ||
2592 | for(;;) | |
2593 | { | |
2594 | /* Make sure that we always have enough lookahead, except | |
2595 | * at the end of the input file. We need maxMatch bytes | |
2596 | * for the next match, plus minMatch bytes to insert the | |
2597 | * string following the next match. | |
2598 | */ | |
2599 | if(lookahead_ < kMinLookahead) | |
2600 | { | |
2601 | fill_window(zs); | |
2602 | if(lookahead_ < kMinLookahead && flush == Flush::none) | |
2603 | return need_more; | |
2604 | if(lookahead_ == 0) | |
2605 | break; /* flush the current block */ | |
2606 | } | |
2607 | ||
2608 | /* Insert the string window[strstart .. strstart+2] in the | |
2609 | * dictionary, and set hash_head to the head of the hash chain: | |
2610 | */ | |
2611 | hash_head = 0; | |
2612 | if(lookahead_ >= minMatch) { | |
2613 | insert_string(hash_head); | |
2614 | } | |
2615 | ||
2616 | /* Find the longest match, discarding those <= prev_length. | |
2617 | * At this point we have always match_length < minMatch | |
2618 | */ | |
2619 | if(hash_head != 0 && strstart_ - hash_head <= max_dist()) { | |
2620 | /* To simplify the code, we prevent matches with the string | |
2621 | * of window index 0 (in particular we have to avoid a match | |
2622 | * of the string with itself at the start of the input file). | |
2623 | */ | |
2624 | match_length_ = longest_match (hash_head); | |
2625 | /* longest_match() sets match_start */ | |
2626 | } | |
2627 | if(match_length_ >= minMatch) | |
2628 | { | |
2629 | tr_tally_dist(strstart_ - match_start_, | |
2630 | match_length_ - minMatch, bflush); | |
2631 | ||
2632 | lookahead_ -= match_length_; | |
2633 | ||
2634 | /* Insert new strings in the hash table only if the match length | |
2635 | * is not too large. This saves time but degrades compression. | |
2636 | */ | |
2637 | if(match_length_ <= max_lazy_match_ && | |
2638 | lookahead_ >= minMatch) { | |
2639 | match_length_--; /* string at strstart already in table */ | |
2640 | do | |
2641 | { | |
2642 | strstart_++; | |
2643 | insert_string(hash_head); | |
2644 | /* strstart never exceeds WSIZE-maxMatch, so there are | |
2645 | * always minMatch bytes ahead. | |
2646 | */ | |
2647 | } | |
2648 | while(--match_length_ != 0); | |
2649 | strstart_++; | |
2650 | } | |
2651 | else | |
2652 | { | |
2653 | strstart_ += match_length_; | |
2654 | match_length_ = 0; | |
2655 | ins_h_ = window_[strstart_]; | |
2656 | update_hash(ins_h_, window_[strstart_+1]); | |
2657 | /* If lookahead < minMatch, ins_h is garbage, but it does not | |
2658 | * matter since it will be recomputed at next deflate call. | |
2659 | */ | |
2660 | } | |
2661 | } | |
2662 | else | |
2663 | { | |
2664 | /* No match, output a literal byte */ | |
2665 | tr_tally_lit(window_[strstart_], bflush); | |
2666 | lookahead_--; | |
2667 | strstart_++; | |
2668 | } | |
2669 | if(bflush) | |
2670 | { | |
2671 | flush_block(zs, false); | |
2672 | if(zs.avail_out == 0) | |
2673 | return need_more; | |
2674 | } | |
2675 | } | |
2676 | insert_ = strstart_ < minMatch-1 ? strstart_ : minMatch-1; | |
2677 | if(flush == Flush::finish) | |
2678 | { | |
2679 | flush_block(zs, true); | |
2680 | if(zs.avail_out == 0) | |
2681 | return finish_started; | |
2682 | return finish_done; | |
2683 | } | |
2684 | if(last_lit_) | |
2685 | { | |
2686 | flush_block(zs, false); | |
2687 | if(zs.avail_out == 0) | |
2688 | return need_more; | |
2689 | } | |
2690 | return block_done; | |
2691 | } | |
2692 | ||
2693 | /* Same as above, but achieves better compression. We use a lazy | |
2694 | evaluation for matches: a match is finally adopted only if there is | |
2695 | no better match at the next window position. | |
2696 | */ | |
2697 | template<class> | |
2698 | inline | |
2699 | auto | |
2700 | deflate_stream:: | |
2701 | f_slow(z_params& zs, Flush flush) -> | |
2702 | block_state | |
2703 | { | |
2704 | IPos hash_head; /* head of hash chain */ | |
2705 | bool bflush; /* set if current block must be flushed */ | |
2706 | ||
2707 | /* Process the input block. */ | |
2708 | for(;;) | |
2709 | { | |
2710 | /* Make sure that we always have enough lookahead, except | |
2711 | * at the end of the input file. We need maxMatch bytes | |
2712 | * for the next match, plus minMatch bytes to insert the | |
2713 | * string following the next match. | |
2714 | */ | |
2715 | if(lookahead_ < kMinLookahead) | |
2716 | { | |
2717 | fill_window(zs); | |
2718 | if(lookahead_ < kMinLookahead && flush == Flush::none) | |
2719 | return need_more; | |
2720 | if(lookahead_ == 0) | |
2721 | break; /* flush the current block */ | |
2722 | } | |
2723 | ||
2724 | /* Insert the string window[strstart .. strstart+2] in the | |
2725 | * dictionary, and set hash_head to the head of the hash chain: | |
2726 | */ | |
2727 | hash_head = 0; | |
2728 | if(lookahead_ >= minMatch) | |
2729 | insert_string(hash_head); | |
2730 | ||
2731 | /* Find the longest match, discarding those <= prev_length. | |
2732 | */ | |
2733 | prev_length_ = match_length_, prev_match_ = match_start_; | |
2734 | match_length_ = minMatch-1; | |
2735 | ||
2736 | if(hash_head != 0 && prev_length_ < max_lazy_match_ && | |
2737 | strstart_ - hash_head <= max_dist()) | |
2738 | { | |
2739 | /* To simplify the code, we prevent matches with the string | |
2740 | * of window index 0 (in particular we have to avoid a match | |
2741 | * of the string with itself at the start of the input file). | |
2742 | */ | |
2743 | match_length_ = longest_match(hash_head); | |
2744 | /* longest_match() sets match_start */ | |
2745 | ||
2746 | if(match_length_ <= 5 && (strategy_ == Strategy::filtered | |
2747 | || (match_length_ == minMatch && | |
2748 | strstart_ - match_start_ > kTooFar) | |
2749 | )) | |
2750 | { | |
2751 | /* If prev_match is also minMatch, match_start is garbage | |
2752 | * but we will ignore the current match anyway. | |
2753 | */ | |
2754 | match_length_ = minMatch-1; | |
2755 | } | |
2756 | } | |
2757 | /* If there was a match at the previous step and the current | |
2758 | * match is not better, output the previous match: | |
2759 | */ | |
2760 | if(prev_length_ >= minMatch && match_length_ <= prev_length_) | |
2761 | { | |
2762 | /* Do not insert strings in hash table beyond this. */ | |
2763 | uInt max_insert = strstart_ + lookahead_ - minMatch; | |
2764 | ||
2765 | tr_tally_dist(strstart_ -1 - prev_match_, | |
2766 | prev_length_ - minMatch, bflush); | |
2767 | ||
2768 | /* Insert in hash table all strings up to the end of the match. | |
2769 | * strstart-1 and strstart are already inserted. If there is not | |
2770 | * enough lookahead, the last two strings are not inserted in | |
2771 | * the hash table. | |
2772 | */ | |
2773 | lookahead_ -= prev_length_-1; | |
2774 | prev_length_ -= 2; | |
2775 | do { | |
2776 | if(++strstart_ <= max_insert) | |
2777 | insert_string(hash_head); | |
2778 | } | |
2779 | while(--prev_length_ != 0); | |
2780 | match_available_ = 0; | |
2781 | match_length_ = minMatch-1; | |
2782 | strstart_++; | |
2783 | ||
2784 | if(bflush) | |
2785 | { | |
2786 | flush_block(zs, false); | |
2787 | if(zs.avail_out == 0) | |
2788 | return need_more; | |
2789 | } | |
2790 | ||
2791 | } | |
2792 | else if(match_available_) | |
2793 | { | |
2794 | /* If there was no match at the previous position, output a | |
2795 | * single literal. If there was a match but the current match | |
2796 | * is longer, truncate the previous match to a single literal. | |
2797 | */ | |
2798 | tr_tally_lit(window_[strstart_-1], bflush); | |
2799 | if(bflush) | |
2800 | flush_block(zs, false); | |
2801 | strstart_++; | |
2802 | lookahead_--; | |
2803 | if(zs.avail_out == 0) | |
2804 | return need_more; | |
2805 | } | |
2806 | else | |
2807 | { | |
2808 | /* There is no previous match to compare with, wait for | |
2809 | * the next step to decide. | |
2810 | */ | |
2811 | match_available_ = 1; | |
2812 | strstart_++; | |
2813 | lookahead_--; | |
2814 | } | |
2815 | } | |
2816 | BOOST_ASSERT(flush != Flush::none); | |
2817 | if(match_available_) | |
2818 | { | |
2819 | tr_tally_lit(window_[strstart_-1], bflush); | |
2820 | match_available_ = 0; | |
2821 | } | |
2822 | insert_ = strstart_ < minMatch-1 ? strstart_ : minMatch-1; | |
2823 | if(flush == Flush::finish) | |
2824 | { | |
2825 | flush_block(zs, true); | |
2826 | if(zs.avail_out == 0) | |
2827 | return finish_started; | |
2828 | return finish_done; | |
2829 | } | |
2830 | if(last_lit_) | |
2831 | { | |
2832 | flush_block(zs, false); | |
2833 | if(zs.avail_out == 0) | |
2834 | return need_more; | |
2835 | } | |
2836 | return block_done; | |
2837 | } | |
2838 | ||
2839 | /* For Strategy::rle, simply look for runs of bytes, generate matches only of distance | |
2840 | one. Do not maintain a hash table. (It will be regenerated if this run of | |
2841 | deflate switches away from Strategy::rle.) | |
2842 | */ | |
2843 | template<class> | |
2844 | inline | |
2845 | auto | |
2846 | deflate_stream:: | |
2847 | f_rle(z_params& zs, Flush flush) -> | |
2848 | block_state | |
2849 | { | |
2850 | bool bflush; // set if current block must be flushed | |
2851 | uInt prev; // byte at distance one to match | |
2852 | Byte *scan, *strend; // scan goes up to strend for length of run | |
2853 | ||
2854 | for(;;) | |
2855 | { | |
2856 | /* Make sure that we always have enough lookahead, except | |
2857 | * at the end of the input file. We need maxMatch bytes | |
2858 | * for the longest run, plus one for the unrolled loop. | |
2859 | */ | |
2860 | if(lookahead_ <= maxMatch) { | |
2861 | fill_window(zs); | |
2862 | if(lookahead_ <= maxMatch && flush == Flush::none) { | |
2863 | return need_more; | |
2864 | } | |
2865 | if(lookahead_ == 0) break; /* flush the current block */ | |
2866 | } | |
2867 | ||
2868 | /* See how many times the previous byte repeats */ | |
2869 | match_length_ = 0; | |
2870 | if(lookahead_ >= minMatch && strstart_ > 0) { | |
2871 | scan = window_ + strstart_ - 1; | |
2872 | prev = *scan; | |
2873 | if(prev == *++scan && prev == *++scan && prev == *++scan) { | |
2874 | strend = window_ + strstart_ + maxMatch; | |
2875 | do { | |
2876 | } while(prev == *++scan && prev == *++scan && | |
2877 | prev == *++scan && prev == *++scan && | |
2878 | prev == *++scan && prev == *++scan && | |
2879 | prev == *++scan && prev == *++scan && | |
2880 | scan < strend); | |
2881 | match_length_ = maxMatch - (int)(strend - scan); | |
2882 | if(match_length_ > lookahead_) | |
2883 | match_length_ = lookahead_; | |
2884 | } | |
2885 | BOOST_ASSERT(scan <= window_+(uInt)(window_size_-1)); | |
2886 | } | |
2887 | ||
2888 | /* Emit match if have run of minMatch or longer, else emit literal */ | |
2889 | if(match_length_ >= minMatch) { | |
2890 | tr_tally_dist(1, match_length_ - minMatch, bflush); | |
2891 | ||
2892 | lookahead_ -= match_length_; | |
2893 | strstart_ += match_length_; | |
2894 | match_length_ = 0; | |
2895 | } else { | |
2896 | /* No match, output a literal byte */ | |
2897 | tr_tally_lit(window_[strstart_], bflush); | |
2898 | lookahead_--; | |
2899 | strstart_++; | |
2900 | } | |
2901 | if(bflush) | |
2902 | { | |
2903 | flush_block(zs, false); | |
2904 | if(zs.avail_out == 0) | |
2905 | return need_more; | |
2906 | } | |
2907 | } | |
2908 | insert_ = 0; | |
2909 | if(flush == Flush::finish) | |
2910 | { | |
2911 | flush_block(zs, true); | |
2912 | if(zs.avail_out == 0) | |
2913 | return finish_started; | |
2914 | return finish_done; | |
2915 | } | |
2916 | if(last_lit_) | |
2917 | { | |
2918 | flush_block(zs, false); | |
2919 | if(zs.avail_out == 0) | |
2920 | return need_more; | |
2921 | } | |
2922 | return block_done; | |
2923 | } | |
2924 | ||
2925 | /* =========================================================================== | |
2926 | * For Strategy::huffman, do not look for matches. Do not maintain a hash table. | |
2927 | * (It will be regenerated if this run of deflate switches away from Huffman.) | |
2928 | */ | |
2929 | template<class> | |
2930 | inline | |
2931 | auto | |
2932 | deflate_stream:: | |
2933 | f_huff(z_params& zs, Flush flush) -> | |
2934 | block_state | |
2935 | { | |
2936 | bool bflush; // set if current block must be flushed | |
2937 | ||
2938 | for(;;) | |
2939 | { | |
2940 | // Make sure that we have a literal to write. | |
2941 | if(lookahead_ == 0) | |
2942 | { | |
2943 | fill_window(zs); | |
2944 | if(lookahead_ == 0) | |
2945 | { | |
2946 | if(flush == Flush::none) | |
2947 | return need_more; | |
2948 | break; // flush the current block | |
2949 | } | |
2950 | } | |
2951 | ||
2952 | // Output a literal byte | |
2953 | match_length_ = 0; | |
2954 | tr_tally_lit(window_[strstart_], bflush); | |
2955 | lookahead_--; | |
2956 | strstart_++; | |
2957 | if(bflush) | |
2958 | { | |
2959 | flush_block(zs, false); | |
2960 | if(zs.avail_out == 0) | |
2961 | return need_more; | |
2962 | } | |
2963 | } | |
2964 | insert_ = 0; | |
2965 | if(flush == Flush::finish) | |
2966 | { | |
2967 | flush_block(zs, true); | |
2968 | if(zs.avail_out == 0) | |
2969 | return finish_started; | |
2970 | return finish_done; | |
2971 | } | |
2972 | if(last_lit_) | |
2973 | { | |
2974 | flush_block(zs, false); | |
2975 | if(zs.avail_out == 0) | |
2976 | return need_more; | |
2977 | } | |
2978 | return block_done; | |
2979 | } | |
2980 | ||
2981 | } // detail | |
2982 | } // zlib | |
2983 | } // beast | |
2984 | ||
2985 | #endif |