1 | /* vi: set sw=4 ts=4: */ |
---|
2 | /* Small bzip2 deflate implementation, by Rob Landley (rob@landley.net). |
---|
3 | |
---|
4 | Based on bzip2 decompression code by Julian R Seward (jseward@acm.org), |
---|
5 | which also acknowledges contributions by Mike Burrows, David Wheeler, |
---|
6 | Peter Fenwick, Alistair Moffat, Radford Neal, Ian H. Witten, |
---|
7 | Robert Sedgewick, and Jon L. Bentley. |
---|
8 | |
---|
9 | Licensed under GPLv2 or later, see file LICENSE in this source tree. |
---|
10 | */ |
---|
11 | |
---|
12 | /* |
---|
13 | Size and speed optimizations by Manuel Novoa III (mjn3@codepoet.org). |
---|
14 | |
---|
15 | More efficient reading of Huffman codes, a streamlined read_bunzip() |
---|
16 | function, and various other tweaks. In (limited) tests, approximately |
---|
17 | 20% faster than bzcat on x86 and about 10% faster on arm. |
---|
18 | |
---|
19 | Note that about 2/3 of the time is spent in read_bunzip() reversing |
---|
20 | the Burrows-Wheeler transformation. Much of that time is delay |
---|
21 | resulting from cache misses. |
---|
22 | |
---|
23 | (2010 update by vda: profiled "bzcat <84mbyte.bz2 >/dev/null" |
---|
24 | on x86-64 CPU with L2 > 1M: get_next_block is hotter than read_bunzip: |
---|
25 | %time seconds calls function |
---|
26 | 71.01 12.69 444 get_next_block |
---|
27 | 28.65 5.12 93065 read_bunzip |
---|
28 | 00.22 0.04 7736490 get_bits |
---|
29 | 00.11 0.02 47 dealloc_bunzip |
---|
30 | 00.00 0.00 93018 full_write |
---|
31 | ...) |
---|
32 | |
---|
33 | |
---|
34 | I would ask that anyone benefiting from this work, especially those |
---|
35 | using it in commercial products, consider making a donation to my local |
---|
36 | non-profit hospice organization (www.hospiceacadiana.com) in the name of |
---|
37 | the woman I loved, Toni W. Hagan, who passed away Feb. 12, 2003. |
---|
38 | |
---|
39 | Manuel |
---|
40 | */ |
---|
41 | |
---|
42 | #include "libbb.h" |
---|
43 | #include "bb_archive.h" |
---|
44 | |
---|
45 | /* Constants for Huffman coding */ |
---|
46 | #define MAX_GROUPS 6 |
---|
47 | #define GROUP_SIZE 50 /* 64 would have been more efficient */ |
---|
48 | #define MAX_HUFCODE_BITS 20 /* Longest Huffman code allowed */ |
---|
49 | #define MAX_SYMBOLS 258 /* 256 literals + RUNA + RUNB */ |
---|
50 | #define SYMBOL_RUNA 0 |
---|
51 | #define SYMBOL_RUNB 1 |
---|
52 | |
---|
53 | /* Status return values */ |
---|
54 | #define RETVAL_OK 0 |
---|
55 | #define RETVAL_LAST_BLOCK (-1) |
---|
56 | #define RETVAL_NOT_BZIP_DATA (-2) |
---|
57 | #define RETVAL_UNEXPECTED_INPUT_EOF (-3) |
---|
58 | #define RETVAL_SHORT_WRITE (-4) |
---|
59 | #define RETVAL_DATA_ERROR (-5) |
---|
60 | #define RETVAL_OUT_OF_MEMORY (-6) |
---|
61 | #define RETVAL_OBSOLETE_INPUT (-7) |
---|
62 | |
---|
63 | /* Other housekeeping constants */ |
---|
64 | #define IOBUF_SIZE 4096 |
---|
65 | |
---|
66 | /* This is what we know about each Huffman coding group */ |
---|
67 | struct group_data { |
---|
68 | /* We have an extra slot at the end of limit[] for a sentinel value. */ |
---|
69 | int limit[MAX_HUFCODE_BITS+1], base[MAX_HUFCODE_BITS], permute[MAX_SYMBOLS]; |
---|
70 | int minLen, maxLen; |
---|
71 | }; |
---|
72 | |
---|
73 | /* Structure holding all the housekeeping data, including IO buffers and |
---|
74 | * memory that persists between calls to bunzip |
---|
75 | * Found the most used member: |
---|
76 | * cat this_file.c | sed -e 's/"/ /g' -e "s/'/ /g" | xargs -n1 \ |
---|
77 | * | grep 'bd->' | sed 's/^.*bd->/bd->/' | sort | $PAGER |
---|
78 | * and moved it (inbufBitCount) to offset 0. |
---|
79 | */ |
---|
80 | struct bunzip_data { |
---|
81 | /* I/O tracking data (file handles, buffers, positions, etc.) */ |
---|
82 | unsigned inbufBitCount, inbufBits; |
---|
83 | int in_fd, out_fd, inbufCount, inbufPos /*, outbufPos*/; |
---|
84 | uint8_t *inbuf /*,*outbuf*/; |
---|
85 | |
---|
86 | /* State for interrupting output loop */ |
---|
87 | int writeCopies, writePos, writeRunCountdown, writeCount; |
---|
88 | int writeCurrent; /* actually a uint8_t */ |
---|
89 | |
---|
90 | /* The CRC values stored in the block header and calculated from the data */ |
---|
91 | uint32_t headerCRC, totalCRC, writeCRC; |
---|
92 | |
---|
93 | /* Intermediate buffer and its size (in bytes) */ |
---|
94 | uint32_t *dbuf; |
---|
95 | unsigned dbufSize; |
---|
96 | |
---|
97 | /* For I/O error handling */ |
---|
98 | jmp_buf jmpbuf; |
---|
99 | |
---|
100 | /* Big things go last (register-relative addressing can be larger for big offsets) */ |
---|
101 | uint32_t crc32Table[256]; |
---|
102 | uint8_t selectors[32768]; /* nSelectors=15 bits */ |
---|
103 | struct group_data groups[MAX_GROUPS]; /* Huffman coding tables */ |
---|
104 | }; |
---|
105 | /* typedef struct bunzip_data bunzip_data; -- done in .h file */ |
---|
106 | |
---|
107 | |
---|
108 | /* Return the next nnn bits of input. All reads from the compressed input |
---|
109 | are done through this function. All reads are big endian */ |
---|
110 | static unsigned get_bits(bunzip_data *bd, int bits_wanted) |
---|
111 | { |
---|
112 | unsigned bits = 0; |
---|
113 | /* Cache bd->inbufBitCount in a CPU register (hopefully): */ |
---|
114 | int bit_count = bd->inbufBitCount; |
---|
115 | |
---|
116 | /* If we need to get more data from the byte buffer, do so. (Loop getting |
---|
117 | one byte at a time to enforce endianness and avoid unaligned access.) */ |
---|
118 | while (bit_count < bits_wanted) { |
---|
119 | |
---|
120 | /* If we need to read more data from file into byte buffer, do so */ |
---|
121 | if (bd->inbufPos == bd->inbufCount) { |
---|
122 | /* if "no input fd" case: in_fd == -1, read fails, we jump */ |
---|
123 | bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE); |
---|
124 | if (bd->inbufCount <= 0) |
---|
125 | longjmp(bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF); |
---|
126 | bd->inbufPos = 0; |
---|
127 | } |
---|
128 | |
---|
129 | /* Avoid 32-bit overflow (dump bit buffer to top of output) */ |
---|
130 | if (bit_count >= 24) { |
---|
131 | bits = bd->inbufBits & ((1 << bit_count) - 1); |
---|
132 | bits_wanted -= bit_count; |
---|
133 | bits <<= bits_wanted; |
---|
134 | bit_count = 0; |
---|
135 | } |
---|
136 | |
---|
137 | /* Grab next 8 bits of input from buffer. */ |
---|
138 | bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++]; |
---|
139 | bit_count += 8; |
---|
140 | } |
---|
141 | |
---|
142 | /* Calculate result */ |
---|
143 | bit_count -= bits_wanted; |
---|
144 | bd->inbufBitCount = bit_count; |
---|
145 | bits |= (bd->inbufBits >> bit_count) & ((1 << bits_wanted) - 1); |
---|
146 | |
---|
147 | return bits; |
---|
148 | } |
---|
149 | |
---|
150 | /* Unpacks the next block and sets up for the inverse Burrows-Wheeler step. */ |
---|
151 | static int get_next_block(bunzip_data *bd) |
---|
152 | { |
---|
153 | struct group_data *hufGroup; |
---|
154 | int dbufCount, dbufSize, groupCount, *base, *limit, selector, |
---|
155 | i, j, t, runPos, symCount, symTotal, nSelectors, byteCount[256]; |
---|
156 | int runCnt = runCnt; /* for compiler */ |
---|
157 | uint8_t uc, symToByte[256], mtfSymbol[256], *selectors; |
---|
158 | uint32_t *dbuf; |
---|
159 | unsigned origPtr; |
---|
160 | |
---|
161 | dbuf = bd->dbuf; |
---|
162 | dbufSize = bd->dbufSize; |
---|
163 | selectors = bd->selectors; |
---|
164 | |
---|
165 | /* In bbox, we are ok with aborting through setjmp which is set up in start_bunzip */ |
---|
166 | #if 0 |
---|
167 | /* Reset longjmp I/O error handling */ |
---|
168 | i = setjmp(bd->jmpbuf); |
---|
169 | if (i) return i; |
---|
170 | #endif |
---|
171 | |
---|
172 | /* Read in header signature and CRC, then validate signature. |
---|
173 | (last block signature means CRC is for whole file, return now) */ |
---|
174 | i = get_bits(bd, 24); |
---|
175 | j = get_bits(bd, 24); |
---|
176 | bd->headerCRC = get_bits(bd, 32); |
---|
177 | if ((i == 0x177245) && (j == 0x385090)) return RETVAL_LAST_BLOCK; |
---|
178 | if ((i != 0x314159) || (j != 0x265359)) return RETVAL_NOT_BZIP_DATA; |
---|
179 | |
---|
180 | /* We can add support for blockRandomised if anybody complains. There was |
---|
181 | some code for this in busybox 1.0.0-pre3, but nobody ever noticed that |
---|
182 | it didn't actually work. */ |
---|
183 | if (get_bits(bd, 1)) return RETVAL_OBSOLETE_INPUT; |
---|
184 | origPtr = get_bits(bd, 24); |
---|
185 | if ((int)origPtr > dbufSize) return RETVAL_DATA_ERROR; |
---|
186 | |
---|
187 | /* mapping table: if some byte values are never used (encoding things |
---|
188 | like ascii text), the compression code removes the gaps to have fewer |
---|
189 | symbols to deal with, and writes a sparse bitfield indicating which |
---|
190 | values were present. We make a translation table to convert the symbols |
---|
191 | back to the corresponding bytes. */ |
---|
192 | symTotal = 0; |
---|
193 | i = 0; |
---|
194 | t = get_bits(bd, 16); |
---|
195 | do { |
---|
196 | if (t & (1 << 15)) { |
---|
197 | unsigned inner_map = get_bits(bd, 16); |
---|
198 | do { |
---|
199 | if (inner_map & (1 << 15)) |
---|
200 | symToByte[symTotal++] = i; |
---|
201 | inner_map <<= 1; |
---|
202 | i++; |
---|
203 | } while (i & 15); |
---|
204 | i -= 16; |
---|
205 | } |
---|
206 | t <<= 1; |
---|
207 | i += 16; |
---|
208 | } while (i < 256); |
---|
209 | |
---|
210 | /* How many different Huffman coding groups does this block use? */ |
---|
211 | groupCount = get_bits(bd, 3); |
---|
212 | if (groupCount < 2 || groupCount > MAX_GROUPS) |
---|
213 | return RETVAL_DATA_ERROR; |
---|
214 | |
---|
215 | /* nSelectors: Every GROUP_SIZE many symbols we select a new Huffman coding |
---|
216 | group. Read in the group selector list, which is stored as MTF encoded |
---|
217 | bit runs. (MTF=Move To Front, as each value is used it's moved to the |
---|
218 | start of the list.) */ |
---|
219 | for (i = 0; i < groupCount; i++) |
---|
220 | mtfSymbol[i] = i; |
---|
221 | nSelectors = get_bits(bd, 15); |
---|
222 | if (!nSelectors) |
---|
223 | return RETVAL_DATA_ERROR; |
---|
224 | for (i = 0; i < nSelectors; i++) { |
---|
225 | uint8_t tmp_byte; |
---|
226 | /* Get next value */ |
---|
227 | int n = 0; |
---|
228 | while (get_bits(bd, 1)) { |
---|
229 | if (n >= groupCount) return RETVAL_DATA_ERROR; |
---|
230 | n++; |
---|
231 | } |
---|
232 | /* Decode MTF to get the next selector */ |
---|
233 | tmp_byte = mtfSymbol[n]; |
---|
234 | while (--n >= 0) |
---|
235 | mtfSymbol[n + 1] = mtfSymbol[n]; |
---|
236 | mtfSymbol[0] = selectors[i] = tmp_byte; |
---|
237 | } |
---|
238 | |
---|
239 | /* Read the Huffman coding tables for each group, which code for symTotal |
---|
240 | literal symbols, plus two run symbols (RUNA, RUNB) */ |
---|
241 | symCount = symTotal + 2; |
---|
242 | for (j = 0; j < groupCount; j++) { |
---|
243 | uint8_t length[MAX_SYMBOLS]; |
---|
244 | /* 8 bits is ALMOST enough for temp[], see below */ |
---|
245 | unsigned temp[MAX_HUFCODE_BITS+1]; |
---|
246 | int minLen, maxLen, pp, len_m1; |
---|
247 | |
---|
248 | /* Read Huffman code lengths for each symbol. They're stored in |
---|
249 | a way similar to mtf; record a starting value for the first symbol, |
---|
250 | and an offset from the previous value for every symbol after that. |
---|
251 | (Subtracting 1 before the loop and then adding it back at the end is |
---|
252 | an optimization that makes the test inside the loop simpler: symbol |
---|
253 | length 0 becomes negative, so an unsigned inequality catches it.) */ |
---|
254 | len_m1 = get_bits(bd, 5) - 1; |
---|
255 | for (i = 0; i < symCount; i++) { |
---|
256 | for (;;) { |
---|
257 | int two_bits; |
---|
258 | if ((unsigned)len_m1 > (MAX_HUFCODE_BITS-1)) |
---|
259 | return RETVAL_DATA_ERROR; |
---|
260 | |
---|
261 | /* If first bit is 0, stop. Else second bit indicates whether |
---|
262 | to increment or decrement the value. Optimization: grab 2 |
---|
263 | bits and unget the second if the first was 0. */ |
---|
264 | two_bits = get_bits(bd, 2); |
---|
265 | if (two_bits < 2) { |
---|
266 | bd->inbufBitCount++; |
---|
267 | break; |
---|
268 | } |
---|
269 | |
---|
270 | /* Add one if second bit 1, else subtract 1. Avoids if/else */ |
---|
271 | len_m1 += (((two_bits+1) & 2) - 1); |
---|
272 | } |
---|
273 | |
---|
274 | /* Correct for the initial -1, to get the final symbol length */ |
---|
275 | length[i] = len_m1 + 1; |
---|
276 | } |
---|
277 | |
---|
278 | /* Find largest and smallest lengths in this group */ |
---|
279 | minLen = maxLen = length[0]; |
---|
280 | for (i = 1; i < symCount; i++) { |
---|
281 | if (length[i] > maxLen) maxLen = length[i]; |
---|
282 | else if (length[i] < minLen) minLen = length[i]; |
---|
283 | } |
---|
284 | |
---|
285 | /* Calculate permute[], base[], and limit[] tables from length[]. |
---|
286 | * |
---|
287 | * permute[] is the lookup table for converting Huffman coded symbols |
---|
288 | * into decoded symbols. base[] is the amount to subtract from the |
---|
289 | * value of a Huffman symbol of a given length when using permute[]. |
---|
290 | * |
---|
291 | * limit[] indicates the largest numerical value a symbol with a given |
---|
292 | * number of bits can have. This is how the Huffman codes can vary in |
---|
293 | * length: each code with a value>limit[length] needs another bit. |
---|
294 | */ |
---|
295 | hufGroup = bd->groups + j; |
---|
296 | hufGroup->minLen = minLen; |
---|
297 | hufGroup->maxLen = maxLen; |
---|
298 | |
---|
299 | /* Note that minLen can't be smaller than 1, so we adjust the base |
---|
300 | and limit array pointers so we're not always wasting the first |
---|
301 | entry. We do this again when using them (during symbol decoding). */ |
---|
302 | base = hufGroup->base - 1; |
---|
303 | limit = hufGroup->limit - 1; |
---|
304 | |
---|
305 | /* Calculate permute[]. Concurently, initialize temp[] and limit[]. */ |
---|
306 | pp = 0; |
---|
307 | for (i = minLen; i <= maxLen; i++) { |
---|
308 | int k; |
---|
309 | temp[i] = limit[i] = 0; |
---|
310 | for (k = 0; k < symCount; k++) |
---|
311 | if (length[k] == i) |
---|
312 | hufGroup->permute[pp++] = k; |
---|
313 | } |
---|
314 | |
---|
315 | /* Count symbols coded for at each bit length */ |
---|
316 | /* NB: in pathological cases, temp[8] can end ip being 256. |
---|
317 | * That's why uint8_t is too small for temp[]. */ |
---|
318 | for (i = 0; i < symCount; i++) temp[length[i]]++; |
---|
319 | |
---|
320 | /* Calculate limit[] (the largest symbol-coding value at each bit |
---|
321 | * length, which is (previous limit<<1)+symbols at this level), and |
---|
322 | * base[] (number of symbols to ignore at each bit length, which is |
---|
323 | * limit minus the cumulative count of symbols coded for already). */ |
---|
324 | pp = t = 0; |
---|
325 | for (i = minLen; i < maxLen;) { |
---|
326 | unsigned temp_i = temp[i]; |
---|
327 | |
---|
328 | pp += temp_i; |
---|
329 | |
---|
330 | /* We read the largest possible symbol size and then unget bits |
---|
331 | after determining how many we need, and those extra bits could |
---|
332 | be set to anything. (They're noise from future symbols.) At |
---|
333 | each level we're really only interested in the first few bits, |
---|
334 | so here we set all the trailing to-be-ignored bits to 1 so they |
---|
335 | don't affect the value>limit[length] comparison. */ |
---|
336 | limit[i] = (pp << (maxLen - i)) - 1; |
---|
337 | pp <<= 1; |
---|
338 | t += temp_i; |
---|
339 | base[++i] = pp - t; |
---|
340 | } |
---|
341 | limit[maxLen] = pp + temp[maxLen] - 1; |
---|
342 | limit[maxLen+1] = INT_MAX; /* Sentinel value for reading next sym. */ |
---|
343 | base[minLen] = 0; |
---|
344 | } |
---|
345 | |
---|
346 | /* We've finished reading and digesting the block header. Now read this |
---|
347 | block's Huffman coded symbols from the file and undo the Huffman coding |
---|
348 | and run length encoding, saving the result into dbuf[dbufCount++] = uc */ |
---|
349 | |
---|
350 | /* Initialize symbol occurrence counters and symbol Move To Front table */ |
---|
351 | /*memset(byteCount, 0, sizeof(byteCount)); - smaller, but slower */ |
---|
352 | for (i = 0; i < 256; i++) { |
---|
353 | byteCount[i] = 0; |
---|
354 | mtfSymbol[i] = (uint8_t)i; |
---|
355 | } |
---|
356 | |
---|
357 | /* Loop through compressed symbols. */ |
---|
358 | |
---|
359 | runPos = dbufCount = selector = 0; |
---|
360 | for (;;) { |
---|
361 | int nextSym; |
---|
362 | |
---|
363 | /* Fetch next Huffman coding group from list. */ |
---|
364 | symCount = GROUP_SIZE - 1; |
---|
365 | if (selector >= nSelectors) return RETVAL_DATA_ERROR; |
---|
366 | hufGroup = bd->groups + selectors[selector++]; |
---|
367 | base = hufGroup->base - 1; |
---|
368 | limit = hufGroup->limit - 1; |
---|
369 | |
---|
370 | continue_this_group: |
---|
371 | /* Read next Huffman-coded symbol. */ |
---|
372 | |
---|
373 | /* Note: It is far cheaper to read maxLen bits and back up than it is |
---|
374 | to read minLen bits and then add additional bit at a time, testing |
---|
375 | as we go. Because there is a trailing last block (with file CRC), |
---|
376 | there is no danger of the overread causing an unexpected EOF for a |
---|
377 | valid compressed file. |
---|
378 | */ |
---|
379 | if (1) { |
---|
380 | /* As a further optimization, we do the read inline |
---|
381 | (falling back to a call to get_bits if the buffer runs dry). |
---|
382 | */ |
---|
383 | int new_cnt; |
---|
384 | while ((new_cnt = bd->inbufBitCount - hufGroup->maxLen) < 0) { |
---|
385 | /* bd->inbufBitCount < hufGroup->maxLen */ |
---|
386 | if (bd->inbufPos == bd->inbufCount) { |
---|
387 | nextSym = get_bits(bd, hufGroup->maxLen); |
---|
388 | goto got_huff_bits; |
---|
389 | } |
---|
390 | bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++]; |
---|
391 | bd->inbufBitCount += 8; |
---|
392 | }; |
---|
393 | bd->inbufBitCount = new_cnt; /* "bd->inbufBitCount -= hufGroup->maxLen;" */ |
---|
394 | nextSym = (bd->inbufBits >> new_cnt) & ((1 << hufGroup->maxLen) - 1); |
---|
395 | got_huff_bits: ; |
---|
396 | } else { /* unoptimized equivalent */ |
---|
397 | nextSym = get_bits(bd, hufGroup->maxLen); |
---|
398 | } |
---|
399 | /* Figure how many bits are in next symbol and unget extras */ |
---|
400 | i = hufGroup->minLen; |
---|
401 | while (nextSym > limit[i]) ++i; |
---|
402 | j = hufGroup->maxLen - i; |
---|
403 | if (j < 0) |
---|
404 | return RETVAL_DATA_ERROR; |
---|
405 | bd->inbufBitCount += j; |
---|
406 | |
---|
407 | /* Huffman decode value to get nextSym (with bounds checking) */ |
---|
408 | nextSym = (nextSym >> j) - base[i]; |
---|
409 | if ((unsigned)nextSym >= MAX_SYMBOLS) |
---|
410 | return RETVAL_DATA_ERROR; |
---|
411 | nextSym = hufGroup->permute[nextSym]; |
---|
412 | |
---|
413 | /* We have now decoded the symbol, which indicates either a new literal |
---|
414 | byte, or a repeated run of the most recent literal byte. First, |
---|
415 | check if nextSym indicates a repeated run, and if so loop collecting |
---|
416 | how many times to repeat the last literal. */ |
---|
417 | if ((unsigned)nextSym <= SYMBOL_RUNB) { /* RUNA or RUNB */ |
---|
418 | |
---|
419 | /* If this is the start of a new run, zero out counter */ |
---|
420 | if (runPos == 0) { |
---|
421 | runPos = 1; |
---|
422 | runCnt = 0; |
---|
423 | } |
---|
424 | |
---|
425 | /* Neat trick that saves 1 symbol: instead of or-ing 0 or 1 at |
---|
426 | each bit position, add 1 or 2 instead. For example, |
---|
427 | 1011 is 1<<0 + 1<<1 + 2<<2. 1010 is 2<<0 + 2<<1 + 1<<2. |
---|
428 | You can make any bit pattern that way using 1 less symbol than |
---|
429 | the basic or 0/1 method (except all bits 0, which would use no |
---|
430 | symbols, but a run of length 0 doesn't mean anything in this |
---|
431 | context). Thus space is saved. */ |
---|
432 | runCnt += (runPos << nextSym); /* +runPos if RUNA; +2*runPos if RUNB */ |
---|
433 | if (runPos < dbufSize) runPos <<= 1; |
---|
434 | goto end_of_huffman_loop; |
---|
435 | } |
---|
436 | |
---|
437 | /* When we hit the first non-run symbol after a run, we now know |
---|
438 | how many times to repeat the last literal, so append that many |
---|
439 | copies to our buffer of decoded symbols (dbuf) now. (The last |
---|
440 | literal used is the one at the head of the mtfSymbol array.) */ |
---|
441 | if (runPos != 0) { |
---|
442 | uint8_t tmp_byte; |
---|
443 | if (dbufCount + runCnt >= dbufSize) return RETVAL_DATA_ERROR; |
---|
444 | tmp_byte = symToByte[mtfSymbol[0]]; |
---|
445 | byteCount[tmp_byte] += runCnt; |
---|
446 | while (--runCnt >= 0) dbuf[dbufCount++] = (uint32_t)tmp_byte; |
---|
447 | runPos = 0; |
---|
448 | } |
---|
449 | |
---|
450 | /* Is this the terminating symbol? */ |
---|
451 | if (nextSym > symTotal) break; |
---|
452 | |
---|
453 | /* At this point, nextSym indicates a new literal character. Subtract |
---|
454 | one to get the position in the MTF array at which this literal is |
---|
455 | currently to be found. (Note that the result can't be -1 or 0, |
---|
456 | because 0 and 1 are RUNA and RUNB. But another instance of the |
---|
457 | first symbol in the mtf array, position 0, would have been handled |
---|
458 | as part of a run above. Therefore 1 unused mtf position minus |
---|
459 | 2 non-literal nextSym values equals -1.) */ |
---|
460 | if (dbufCount >= dbufSize) return RETVAL_DATA_ERROR; |
---|
461 | i = nextSym - 1; |
---|
462 | uc = mtfSymbol[i]; |
---|
463 | |
---|
464 | /* Adjust the MTF array. Since we typically expect to move only a |
---|
465 | * small number of symbols, and are bound by 256 in any case, using |
---|
466 | * memmove here would typically be bigger and slower due to function |
---|
467 | * call overhead and other assorted setup costs. */ |
---|
468 | do { |
---|
469 | mtfSymbol[i] = mtfSymbol[i-1]; |
---|
470 | } while (--i); |
---|
471 | mtfSymbol[0] = uc; |
---|
472 | uc = symToByte[uc]; |
---|
473 | |
---|
474 | /* We have our literal byte. Save it into dbuf. */ |
---|
475 | byteCount[uc]++; |
---|
476 | dbuf[dbufCount++] = (uint32_t)uc; |
---|
477 | |
---|
478 | /* Skip group initialization if we're not done with this group. Done |
---|
479 | * this way to avoid compiler warning. */ |
---|
480 | end_of_huffman_loop: |
---|
481 | if (--symCount >= 0) goto continue_this_group; |
---|
482 | } |
---|
483 | |
---|
484 | /* At this point, we've read all the Huffman-coded symbols (and repeated |
---|
485 | runs) for this block from the input stream, and decoded them into the |
---|
486 | intermediate buffer. There are dbufCount many decoded bytes in dbuf[]. |
---|
487 | Now undo the Burrows-Wheeler transform on dbuf. |
---|
488 | See http://dogma.net/markn/articles/bwt/bwt.htm |
---|
489 | */ |
---|
490 | |
---|
491 | /* Turn byteCount into cumulative occurrence counts of 0 to n-1. */ |
---|
492 | j = 0; |
---|
493 | for (i = 0; i < 256; i++) { |
---|
494 | int tmp_count = j + byteCount[i]; |
---|
495 | byteCount[i] = j; |
---|
496 | j = tmp_count; |
---|
497 | } |
---|
498 | |
---|
499 | /* Figure out what order dbuf would be in if we sorted it. */ |
---|
500 | for (i = 0; i < dbufCount; i++) { |
---|
501 | uint8_t tmp_byte = (uint8_t)dbuf[i]; |
---|
502 | int tmp_count = byteCount[tmp_byte]; |
---|
503 | dbuf[tmp_count] |= (i << 8); |
---|
504 | byteCount[tmp_byte] = tmp_count + 1; |
---|
505 | } |
---|
506 | |
---|
507 | /* Decode first byte by hand to initialize "previous" byte. Note that it |
---|
508 | doesn't get output, and if the first three characters are identical |
---|
509 | it doesn't qualify as a run (hence writeRunCountdown=5). */ |
---|
510 | if (dbufCount) { |
---|
511 | uint32_t tmp; |
---|
512 | if ((int)origPtr >= dbufCount) return RETVAL_DATA_ERROR; |
---|
513 | tmp = dbuf[origPtr]; |
---|
514 | bd->writeCurrent = (uint8_t)tmp; |
---|
515 | bd->writePos = (tmp >> 8); |
---|
516 | bd->writeRunCountdown = 5; |
---|
517 | } |
---|
518 | bd->writeCount = dbufCount; |
---|
519 | |
---|
520 | return RETVAL_OK; |
---|
521 | } |
---|
522 | |
---|
523 | /* Undo Burrows-Wheeler transform on intermediate buffer to produce output. |
---|
524 | If start_bunzip was initialized with out_fd=-1, then up to len bytes of |
---|
525 | data are written to outbuf. Return value is number of bytes written or |
---|
526 | error (all errors are negative numbers). If out_fd!=-1, outbuf and len |
---|
527 | are ignored, data is written to out_fd and return is RETVAL_OK or error. |
---|
528 | |
---|
529 | NB: read_bunzip returns < 0 on error, or the number of *unfilled* bytes |
---|
530 | in outbuf. IOW: on EOF returns len ("all bytes are not filled"), not 0. |
---|
531 | (Why? This allows to get rid of one local variable) |
---|
532 | */ |
---|
533 | int FAST_FUNC read_bunzip(bunzip_data *bd, char *outbuf, int len) |
---|
534 | { |
---|
535 | const uint32_t *dbuf; |
---|
536 | int pos, current, previous; |
---|
537 | uint32_t CRC; |
---|
538 | |
---|
539 | /* If we already have error/end indicator, return it */ |
---|
540 | if (bd->writeCount < 0) |
---|
541 | return bd->writeCount; |
---|
542 | |
---|
543 | dbuf = bd->dbuf; |
---|
544 | |
---|
545 | /* Register-cached state (hopefully): */ |
---|
546 | pos = bd->writePos; |
---|
547 | current = bd->writeCurrent; |
---|
548 | CRC = bd->writeCRC; /* small loss on x86-32 (not enough regs), win on x86-64 */ |
---|
549 | |
---|
550 | /* We will always have pending decoded data to write into the output |
---|
551 | buffer unless this is the very first call (in which case we haven't |
---|
552 | Huffman-decoded a block into the intermediate buffer yet). */ |
---|
553 | if (bd->writeCopies) { |
---|
554 | |
---|
555 | dec_writeCopies: |
---|
556 | /* Inside the loop, writeCopies means extra copies (beyond 1) */ |
---|
557 | --bd->writeCopies; |
---|
558 | |
---|
559 | /* Loop outputting bytes */ |
---|
560 | for (;;) { |
---|
561 | |
---|
562 | /* If the output buffer is full, save cached state and return */ |
---|
563 | if (--len < 0) { |
---|
564 | /* Unlikely branch. |
---|
565 | * Use of "goto" instead of keeping code here |
---|
566 | * helps compiler to realize this. */ |
---|
567 | goto outbuf_full; |
---|
568 | } |
---|
569 | |
---|
570 | /* Write next byte into output buffer, updating CRC */ |
---|
571 | *outbuf++ = current; |
---|
572 | CRC = (CRC << 8) ^ bd->crc32Table[(CRC >> 24) ^ current]; |
---|
573 | |
---|
574 | /* Loop now if we're outputting multiple copies of this byte */ |
---|
575 | if (bd->writeCopies) { |
---|
576 | /* Unlikely branch */ |
---|
577 | /*--bd->writeCopies;*/ |
---|
578 | /*continue;*/ |
---|
579 | /* Same, but (ab)using other existing --writeCopies operation |
---|
580 | * (and this if() compiles into just test+branch pair): */ |
---|
581 | goto dec_writeCopies; |
---|
582 | } |
---|
583 | decode_next_byte: |
---|
584 | if (--bd->writeCount < 0) |
---|
585 | break; /* input block is fully consumed, need next one */ |
---|
586 | |
---|
587 | /* Follow sequence vector to undo Burrows-Wheeler transform */ |
---|
588 | previous = current; |
---|
589 | pos = dbuf[pos]; |
---|
590 | current = (uint8_t)pos; |
---|
591 | pos >>= 8; |
---|
592 | |
---|
593 | /* After 3 consecutive copies of the same byte, the 4th |
---|
594 | * is a repeat count. We count down from 4 instead |
---|
595 | * of counting up because testing for non-zero is faster */ |
---|
596 | if (--bd->writeRunCountdown != 0) { |
---|
597 | if (current != previous) |
---|
598 | bd->writeRunCountdown = 4; |
---|
599 | } else { |
---|
600 | /* Unlikely branch */ |
---|
601 | /* We have a repeated run, this byte indicates the count */ |
---|
602 | bd->writeCopies = current; |
---|
603 | current = previous; |
---|
604 | bd->writeRunCountdown = 5; |
---|
605 | |
---|
606 | /* Sometimes there are just 3 bytes (run length 0) */ |
---|
607 | if (!bd->writeCopies) goto decode_next_byte; |
---|
608 | |
---|
609 | /* Subtract the 1 copy we'd output anyway to get extras */ |
---|
610 | --bd->writeCopies; |
---|
611 | } |
---|
612 | } /* for(;;) */ |
---|
613 | |
---|
614 | /* Decompression of this input block completed successfully */ |
---|
615 | bd->writeCRC = CRC = ~CRC; |
---|
616 | bd->totalCRC = ((bd->totalCRC << 1) | (bd->totalCRC >> 31)) ^ CRC; |
---|
617 | |
---|
618 | /* If this block had a CRC error, force file level CRC error */ |
---|
619 | if (CRC != bd->headerCRC) { |
---|
620 | bd->totalCRC = bd->headerCRC + 1; |
---|
621 | return RETVAL_LAST_BLOCK; |
---|
622 | } |
---|
623 | } |
---|
624 | |
---|
625 | /* Refill the intermediate buffer by Huffman-decoding next block of input */ |
---|
626 | { |
---|
627 | int r = get_next_block(bd); |
---|
628 | if (r) { /* error/end */ |
---|
629 | bd->writeCount = r; |
---|
630 | return (r != RETVAL_LAST_BLOCK) ? r : len; |
---|
631 | } |
---|
632 | } |
---|
633 | |
---|
634 | CRC = ~0; |
---|
635 | pos = bd->writePos; |
---|
636 | current = bd->writeCurrent; |
---|
637 | goto decode_next_byte; |
---|
638 | |
---|
639 | outbuf_full: |
---|
640 | /* Output buffer is full, save cached state and return */ |
---|
641 | bd->writePos = pos; |
---|
642 | bd->writeCurrent = current; |
---|
643 | bd->writeCRC = CRC; |
---|
644 | |
---|
645 | bd->writeCopies++; |
---|
646 | |
---|
647 | return 0; |
---|
648 | } |
---|
649 | |
---|
650 | /* Allocate the structure, read file header. If in_fd==-1, inbuf must contain |
---|
651 | a complete bunzip file (len bytes long). If in_fd!=-1, inbuf and len are |
---|
652 | ignored, and data is read from file handle into temporary buffer. */ |
---|
653 | |
---|
654 | /* Because bunzip2 is used for help text unpacking, and because bb_show_usage() |
---|
655 | should work for NOFORK applets too, we must be extremely careful to not leak |
---|
656 | any allocations! */ |
---|
657 | int FAST_FUNC start_bunzip(bunzip_data **bdp, int in_fd, |
---|
658 | const void *inbuf, int len) |
---|
659 | { |
---|
660 | bunzip_data *bd; |
---|
661 | unsigned i; |
---|
662 | enum { |
---|
663 | BZh0 = ('B' << 24) + ('Z' << 16) + ('h' << 8) + '0', |
---|
664 | h0 = ('h' << 8) + '0', |
---|
665 | }; |
---|
666 | |
---|
667 | /* Figure out how much data to allocate */ |
---|
668 | i = sizeof(bunzip_data); |
---|
669 | if (in_fd != -1) i += IOBUF_SIZE; |
---|
670 | |
---|
671 | /* Allocate bunzip_data. Most fields initialize to zero. */ |
---|
672 | bd = *bdp = xzalloc(i); |
---|
673 | |
---|
674 | /* Setup input buffer */ |
---|
675 | bd->in_fd = in_fd; |
---|
676 | if (-1 == in_fd) { |
---|
677 | /* in this case, bd->inbuf is read-only */ |
---|
678 | bd->inbuf = (void*)inbuf; /* cast away const-ness */ |
---|
679 | } else { |
---|
680 | bd->inbuf = (uint8_t*)(bd + 1); |
---|
681 | memcpy(bd->inbuf, inbuf, len); |
---|
682 | } |
---|
683 | bd->inbufCount = len; |
---|
684 | |
---|
685 | /* Init the CRC32 table (big endian) */ |
---|
686 | crc32_filltable(bd->crc32Table, 1); |
---|
687 | |
---|
688 | /* Setup for I/O error handling via longjmp */ |
---|
689 | i = setjmp(bd->jmpbuf); |
---|
690 | if (i) return i; |
---|
691 | |
---|
692 | /* Ensure that file starts with "BZh['1'-'9']." */ |
---|
693 | /* Update: now caller verifies 1st two bytes, makes .gz/.bz2 |
---|
694 | * integration easier */ |
---|
695 | /* was: */ |
---|
696 | /* i = get_bits(bd, 32); */ |
---|
697 | /* if ((unsigned)(i - BZh0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA; */ |
---|
698 | i = get_bits(bd, 16); |
---|
699 | if ((unsigned)(i - h0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA; |
---|
700 | |
---|
701 | /* Fourth byte (ascii '1'-'9') indicates block size in units of 100k of |
---|
702 | uncompressed data. Allocate intermediate buffer for block. */ |
---|
703 | /* bd->dbufSize = 100000 * (i - BZh0); */ |
---|
704 | bd->dbufSize = 100000 * (i - h0); |
---|
705 | |
---|
706 | /* Cannot use xmalloc - may leak bd in NOFORK case! */ |
---|
707 | bd->dbuf = malloc_or_warn(bd->dbufSize * sizeof(bd->dbuf[0])); |
---|
708 | if (!bd->dbuf) { |
---|
709 | free(bd); |
---|
710 | xfunc_die(); |
---|
711 | } |
---|
712 | return RETVAL_OK; |
---|
713 | } |
---|
714 | |
---|
715 | void FAST_FUNC dealloc_bunzip(bunzip_data *bd) |
---|
716 | { |
---|
717 | free(bd->dbuf); |
---|
718 | free(bd); |
---|
719 | } |
---|
720 | |
---|
721 | |
---|
722 | /* Decompress src_fd to dst_fd. Stops at end of bzip data, not end of file. */ |
---|
723 | IF_DESKTOP(long long) int FAST_FUNC |
---|
724 | unpack_bz2_stream(transformer_aux_data_t *aux, int src_fd, int dst_fd) |
---|
725 | { |
---|
726 | IF_DESKTOP(long long total_written = 0;) |
---|
727 | bunzip_data *bd; |
---|
728 | char *outbuf; |
---|
729 | int i; |
---|
730 | unsigned len; |
---|
731 | |
---|
732 | if (check_signature16(aux, src_fd, BZIP2_MAGIC)) |
---|
733 | return -1; |
---|
734 | |
---|
735 | outbuf = xmalloc(IOBUF_SIZE); |
---|
736 | len = 0; |
---|
737 | while (1) { /* "Process one BZ... stream" loop */ |
---|
738 | |
---|
739 | i = start_bunzip(&bd, src_fd, outbuf + 2, len); |
---|
740 | |
---|
741 | if (i == 0) { |
---|
742 | while (1) { /* "Produce some output bytes" loop */ |
---|
743 | i = read_bunzip(bd, outbuf, IOBUF_SIZE); |
---|
744 | if (i < 0) /* error? */ |
---|
745 | break; |
---|
746 | i = IOBUF_SIZE - i; /* number of bytes produced */ |
---|
747 | if (i == 0) /* EOF? */ |
---|
748 | break; |
---|
749 | if (i != full_write(dst_fd, outbuf, i)) { |
---|
750 | bb_error_msg("short write"); |
---|
751 | i = RETVAL_SHORT_WRITE; |
---|
752 | goto release_mem; |
---|
753 | } |
---|
754 | IF_DESKTOP(total_written += i;) |
---|
755 | } |
---|
756 | } |
---|
757 | |
---|
758 | if (i != RETVAL_LAST_BLOCK |
---|
759 | /* Observed case when i == RETVAL_OK: |
---|
760 | * "bzcat z.bz2", where "z.bz2" is a bzipped zero-length file |
---|
761 | * (to be exact, z.bz2 is exactly these 14 bytes: |
---|
762 | * 42 5a 68 39 17 72 45 38 50 90 00 00 00 00). |
---|
763 | */ |
---|
764 | && i != RETVAL_OK |
---|
765 | ) { |
---|
766 | bb_error_msg("bunzip error %d", i); |
---|
767 | break; |
---|
768 | } |
---|
769 | if (bd->headerCRC != bd->totalCRC) { |
---|
770 | bb_error_msg("CRC error"); |
---|
771 | break; |
---|
772 | } |
---|
773 | |
---|
774 | /* Successfully unpacked one BZ stream */ |
---|
775 | i = RETVAL_OK; |
---|
776 | |
---|
777 | /* Do we have "BZ..." after last processed byte? |
---|
778 | * pbzip2 (parallelized bzip2) produces such files. |
---|
779 | */ |
---|
780 | len = bd->inbufCount - bd->inbufPos; |
---|
781 | memcpy(outbuf, &bd->inbuf[bd->inbufPos], len); |
---|
782 | if (len < 2) { |
---|
783 | if (safe_read(src_fd, outbuf + len, 2 - len) != 2 - len) |
---|
784 | break; |
---|
785 | len = 2; |
---|
786 | } |
---|
787 | if (*(uint16_t*)outbuf != BZIP2_MAGIC) /* "BZ"? */ |
---|
788 | break; |
---|
789 | dealloc_bunzip(bd); |
---|
790 | len -= 2; |
---|
791 | } |
---|
792 | |
---|
793 | release_mem: |
---|
794 | dealloc_bunzip(bd); |
---|
795 | free(outbuf); |
---|
796 | |
---|
797 | return i ? i : IF_DESKTOP(total_written) + 0; |
---|
798 | } |
---|
799 | |
---|
800 | #ifdef TESTING |
---|
801 | |
---|
802 | static char *const bunzip_errors[] = { |
---|
803 | NULL, "Bad file checksum", "Not bzip data", |
---|
804 | "Unexpected input EOF", "Unexpected output EOF", "Data error", |
---|
805 | "Out of memory", "Obsolete (pre 0.9.5) bzip format not supported" |
---|
806 | }; |
---|
807 | |
---|
808 | /* Dumb little test thing, decompress stdin to stdout */ |
---|
809 | int main(int argc, char **argv) |
---|
810 | { |
---|
811 | int i; |
---|
812 | char c; |
---|
813 | |
---|
814 | int i = unpack_bz2_stream(0, 1); |
---|
815 | if (i < 0) |
---|
816 | fprintf(stderr, "%s\n", bunzip_errors[-i]); |
---|
817 | else if (read(STDIN_FILENO, &c, 1)) |
---|
818 | fprintf(stderr, "Trailing garbage ignored\n"); |
---|
819 | return -i; |
---|
820 | } |
---|
821 | #endif |
---|