Root/
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 | This code is licensed under the LGPLv2: |
10 | LGPL (http://www.gnu.org/copyleft/lgpl.html |
11 | */ |
12 | |
13 | /* |
14 | Size and speed optimizations by Manuel Novoa III (mjn3@codepoet.org). |
15 | |
16 | More efficient reading of Huffman codes, a streamlined read_bunzip() |
17 | function, and various other tweaks. In (limited) tests, approximately |
18 | 20% faster than bzcat on x86 and about 10% faster on arm. |
19 | |
20 | Note that about 2/3 of the time is spent in read_unzip() reversing |
21 | the Burrows-Wheeler transformation. Much of that time is delay |
22 | resulting from cache misses. |
23 | |
24 | I would ask that anyone benefiting from this work, especially those |
25 | using it in commercial products, consider making a donation to my local |
26 | non-profit hospice organization in the name of the woman I loved, who |
27 | passed away Feb. 12, 2003. |
28 | |
29 | In memory of Toni W. Hagan |
30 | |
31 | Hospice of Acadiana, Inc. |
32 | 2600 Johnston St., Suite 200 |
33 | Lafayette, LA 70503-3240 |
34 | |
35 | Phone (337) 232-1234 or 1-800-738-2226 |
36 | Fax (337) 232-1297 |
37 | |
38 | http://www.hospiceacadiana.com/ |
39 | |
40 | Manuel |
41 | */ |
42 | |
43 | /* |
44 | Made it fit for running in Linux Kernel by Alain Knaff (alain@knaff.lu) |
45 | */ |
46 | |
47 | |
48 | #ifdef STATIC |
49 | #define PREBOOT |
50 | #else |
51 | #include <linux/decompress/bunzip2.h> |
52 | #include <linux/slab.h> |
53 | #endif /* STATIC */ |
54 | |
55 | #include <linux/decompress/mm.h> |
56 | |
57 | #ifndef INT_MAX |
58 | #define INT_MAX 0x7fffffff |
59 | #endif |
60 | |
61 | /* Constants for Huffman coding */ |
62 | #define MAX_GROUPS 6 |
63 | #define GROUP_SIZE 50 /* 64 would have been more efficient */ |
64 | #define MAX_HUFCODE_BITS 20 /* Longest Huffman code allowed */ |
65 | #define MAX_SYMBOLS 258 /* 256 literals + RUNA + RUNB */ |
66 | #define SYMBOL_RUNA 0 |
67 | #define SYMBOL_RUNB 1 |
68 | |
69 | /* Status return values */ |
70 | #define RETVAL_OK 0 |
71 | #define RETVAL_LAST_BLOCK (-1) |
72 | #define RETVAL_NOT_BZIP_DATA (-2) |
73 | #define RETVAL_UNEXPECTED_INPUT_EOF (-3) |
74 | #define RETVAL_UNEXPECTED_OUTPUT_EOF (-4) |
75 | #define RETVAL_DATA_ERROR (-5) |
76 | #define RETVAL_OUT_OF_MEMORY (-6) |
77 | #define RETVAL_OBSOLETE_INPUT (-7) |
78 | |
79 | /* Other housekeeping constants */ |
80 | #define BZIP2_IOBUF_SIZE 4096 |
81 | |
82 | /* This is what we know about each Huffman coding group */ |
83 | struct group_data { |
84 | /* We have an extra slot at the end of limit[] for a sentinal value. */ |
85 | int limit[MAX_HUFCODE_BITS+1]; |
86 | int base[MAX_HUFCODE_BITS]; |
87 | int permute[MAX_SYMBOLS]; |
88 | int minLen, maxLen; |
89 | }; |
90 | |
91 | /* Structure holding all the housekeeping data, including IO buffers and |
92 | memory that persists between calls to bunzip */ |
93 | struct bunzip_data { |
94 | /* State for interrupting output loop */ |
95 | int writeCopies, writePos, writeRunCountdown, writeCount, writeCurrent; |
96 | /* I/O tracking data (file handles, buffers, positions, etc.) */ |
97 | int (*fill)(void*, unsigned int); |
98 | int inbufCount, inbufPos /*, outbufPos*/; |
99 | unsigned char *inbuf /*,*outbuf*/; |
100 | unsigned int inbufBitCount, inbufBits; |
101 | /* The CRC values stored in the block header and calculated from the |
102 | data */ |
103 | unsigned int crc32Table[256], headerCRC, totalCRC, writeCRC; |
104 | /* Intermediate buffer and its size (in bytes) */ |
105 | unsigned int *dbuf, dbufSize; |
106 | /* These things are a bit too big to go on the stack */ |
107 | unsigned char selectors[32768]; /* nSelectors = 15 bits */ |
108 | struct group_data groups[MAX_GROUPS]; /* Huffman coding tables */ |
109 | int io_error; /* non-zero if we have IO error */ |
110 | int byteCount[256]; |
111 | unsigned char symToByte[256], mtfSymbol[256]; |
112 | }; |
113 | |
114 | |
115 | /* Return the next nnn bits of input. All reads from the compressed input |
116 | are done through this function. All reads are big endian */ |
117 | static unsigned int INIT get_bits(struct bunzip_data *bd, char bits_wanted) |
118 | { |
119 | unsigned int bits = 0; |
120 | |
121 | /* If we need to get more data from the byte buffer, do so. |
122 | (Loop getting one byte at a time to enforce endianness and avoid |
123 | unaligned access.) */ |
124 | while (bd->inbufBitCount < bits_wanted) { |
125 | /* If we need to read more data from file into byte buffer, do |
126 | so */ |
127 | if (bd->inbufPos == bd->inbufCount) { |
128 | if (bd->io_error) |
129 | return 0; |
130 | bd->inbufCount = bd->fill(bd->inbuf, BZIP2_IOBUF_SIZE); |
131 | if (bd->inbufCount <= 0) { |
132 | bd->io_error = RETVAL_UNEXPECTED_INPUT_EOF; |
133 | return 0; |
134 | } |
135 | bd->inbufPos = 0; |
136 | } |
137 | /* Avoid 32-bit overflow (dump bit buffer to top of output) */ |
138 | if (bd->inbufBitCount >= 24) { |
139 | bits = bd->inbufBits&((1 << bd->inbufBitCount)-1); |
140 | bits_wanted -= bd->inbufBitCount; |
141 | bits <<= bits_wanted; |
142 | bd->inbufBitCount = 0; |
143 | } |
144 | /* Grab next 8 bits of input from buffer. */ |
145 | bd->inbufBits = (bd->inbufBits << 8)|bd->inbuf[bd->inbufPos++]; |
146 | bd->inbufBitCount += 8; |
147 | } |
148 | /* Calculate result */ |
149 | bd->inbufBitCount -= bits_wanted; |
150 | bits |= (bd->inbufBits >> bd->inbufBitCount)&((1 << bits_wanted)-1); |
151 | |
152 | return bits; |
153 | } |
154 | |
155 | /* Unpacks the next block and sets up for the inverse burrows-wheeler step. */ |
156 | |
157 | static int INIT get_next_block(struct bunzip_data *bd) |
158 | { |
159 | struct group_data *hufGroup = NULL; |
160 | int *base = NULL; |
161 | int *limit = NULL; |
162 | int dbufCount, nextSym, dbufSize, groupCount, selector, |
163 | i, j, k, t, runPos, symCount, symTotal, nSelectors, *byteCount; |
164 | unsigned char uc, *symToByte, *mtfSymbol, *selectors; |
165 | unsigned int *dbuf, origPtr; |
166 | |
167 | dbuf = bd->dbuf; |
168 | dbufSize = bd->dbufSize; |
169 | selectors = bd->selectors; |
170 | byteCount = bd->byteCount; |
171 | symToByte = bd->symToByte; |
172 | mtfSymbol = bd->mtfSymbol; |
173 | |
174 | /* Read in header signature and CRC, then validate signature. |
175 | (last block signature means CRC is for whole file, return now) */ |
176 | i = get_bits(bd, 24); |
177 | j = get_bits(bd, 24); |
178 | bd->headerCRC = get_bits(bd, 32); |
179 | if ((i == 0x177245) && (j == 0x385090)) |
180 | return RETVAL_LAST_BLOCK; |
181 | if ((i != 0x314159) || (j != 0x265359)) |
182 | return RETVAL_NOT_BZIP_DATA; |
183 | /* We can add support for blockRandomised if anybody complains. |
184 | There was some code for this in busybox 1.0.0-pre3, but nobody ever |
185 | noticed that it didn't actually work. */ |
186 | if (get_bits(bd, 1)) |
187 | return RETVAL_OBSOLETE_INPUT; |
188 | origPtr = get_bits(bd, 24); |
189 | if (origPtr > dbufSize) |
190 | return RETVAL_DATA_ERROR; |
191 | /* mapping table: if some byte values are never used (encoding things |
192 | like ascii text), the compression code removes the gaps to have fewer |
193 | symbols to deal with, and writes a sparse bitfield indicating which |
194 | values were present. We make a translation table to convert the |
195 | symbols back to the corresponding bytes. */ |
196 | t = get_bits(bd, 16); |
197 | symTotal = 0; |
198 | for (i = 0; i < 16; i++) { |
199 | if (t&(1 << (15-i))) { |
200 | k = get_bits(bd, 16); |
201 | for (j = 0; j < 16; j++) |
202 | if (k&(1 << (15-j))) |
203 | symToByte[symTotal++] = (16*i)+j; |
204 | } |
205 | } |
206 | /* How many different Huffman coding groups does this block use? */ |
207 | groupCount = get_bits(bd, 3); |
208 | if (groupCount < 2 || groupCount > MAX_GROUPS) |
209 | return RETVAL_DATA_ERROR; |
210 | /* nSelectors: Every GROUP_SIZE many symbols we select a new |
211 | Huffman coding group. Read in the group selector list, |
212 | which is stored as MTF encoded bit runs. (MTF = Move To |
213 | Front, as each value is used it's moved to the start of the |
214 | list.) */ |
215 | nSelectors = get_bits(bd, 15); |
216 | if (!nSelectors) |
217 | return RETVAL_DATA_ERROR; |
218 | for (i = 0; i < groupCount; i++) |
219 | mtfSymbol[i] = i; |
220 | for (i = 0; i < nSelectors; i++) { |
221 | /* Get next value */ |
222 | for (j = 0; get_bits(bd, 1); j++) |
223 | if (j >= groupCount) |
224 | return RETVAL_DATA_ERROR; |
225 | /* Decode MTF to get the next selector */ |
226 | uc = mtfSymbol[j]; |
227 | for (; j; j--) |
228 | mtfSymbol[j] = mtfSymbol[j-1]; |
229 | mtfSymbol[0] = selectors[i] = uc; |
230 | } |
231 | /* Read the Huffman coding tables for each group, which code |
232 | for symTotal literal symbols, plus two run symbols (RUNA, |
233 | RUNB) */ |
234 | symCount = symTotal+2; |
235 | for (j = 0; j < groupCount; j++) { |
236 | unsigned char length[MAX_SYMBOLS], temp[MAX_HUFCODE_BITS+1]; |
237 | int minLen, maxLen, pp; |
238 | /* Read Huffman code lengths for each symbol. They're |
239 | stored in a way similar to mtf; record a starting |
240 | value for the first symbol, and an offset from the |
241 | previous value for everys symbol after that. |
242 | (Subtracting 1 before the loop and then adding it |
243 | back at the end is an optimization that makes the |
244 | test inside the loop simpler: symbol length 0 |
245 | becomes negative, so an unsigned inequality catches |
246 | it.) */ |
247 | t = get_bits(bd, 5)-1; |
248 | for (i = 0; i < symCount; i++) { |
249 | for (;;) { |
250 | if (((unsigned)t) > (MAX_HUFCODE_BITS-1)) |
251 | return RETVAL_DATA_ERROR; |
252 | |
253 | /* If first bit is 0, stop. Else |
254 | second bit indicates whether to |
255 | increment or decrement the value. |
256 | Optimization: grab 2 bits and unget |
257 | the second if the first was 0. */ |
258 | |
259 | k = get_bits(bd, 2); |
260 | if (k < 2) { |
261 | bd->inbufBitCount++; |
262 | break; |
263 | } |
264 | /* Add one if second bit 1, else |
265 | * subtract 1. Avoids if/else */ |
266 | t += (((k+1)&2)-1); |
267 | } |
268 | /* Correct for the initial -1, to get the |
269 | * final symbol length */ |
270 | length[i] = t+1; |
271 | } |
272 | /* Find largest and smallest lengths in this group */ |
273 | minLen = maxLen = length[0]; |
274 | |
275 | for (i = 1; i < symCount; i++) { |
276 | if (length[i] > maxLen) |
277 | maxLen = length[i]; |
278 | else if (length[i] < minLen) |
279 | minLen = length[i]; |
280 | } |
281 | |
282 | /* Calculate permute[], base[], and limit[] tables from |
283 | * length[]. |
284 | * |
285 | * permute[] is the lookup table for converting |
286 | * Huffman coded symbols into decoded symbols. base[] |
287 | * is the amount to subtract from the value of a |
288 | * Huffman symbol of a given length when using |
289 | * permute[]. |
290 | * |
291 | * limit[] indicates the largest numerical value a |
292 | * symbol with a given number of bits can have. This |
293 | * is how the Huffman codes can vary in length: each |
294 | * code with a value > limit[length] needs another |
295 | * bit. |
296 | */ |
297 | hufGroup = bd->groups+j; |
298 | hufGroup->minLen = minLen; |
299 | hufGroup->maxLen = maxLen; |
300 | /* Note that minLen can't be smaller than 1, so we |
301 | adjust the base and limit array pointers so we're |
302 | not always wasting the first entry. We do this |
303 | again when using them (during symbol decoding).*/ |
304 | base = hufGroup->base-1; |
305 | limit = hufGroup->limit-1; |
306 | /* Calculate permute[]. Concurrently, initialize |
307 | * temp[] and limit[]. */ |
308 | pp = 0; |
309 | for (i = minLen; i <= maxLen; i++) { |
310 | temp[i] = limit[i] = 0; |
311 | for (t = 0; t < symCount; t++) |
312 | if (length[t] == i) |
313 | hufGroup->permute[pp++] = t; |
314 | } |
315 | /* Count symbols coded for at each bit length */ |
316 | for (i = 0; i < symCount; i++) |
317 | temp[length[i]]++; |
318 | /* Calculate limit[] (the largest symbol-coding value |
319 | *at each bit length, which is (previous limit << |
320 | *1)+symbols at this level), and base[] (number of |
321 | *symbols to ignore at each bit length, which is limit |
322 | *minus the cumulative count of symbols coded for |
323 | *already). */ |
324 | pp = t = 0; |
325 | for (i = minLen; i < maxLen; i++) { |
326 | pp += temp[i]; |
327 | /* We read the largest possible symbol size |
328 | and then unget bits after determining how |
329 | many we need, and those extra bits could be |
330 | set to anything. (They're noise from |
331 | future symbols.) At each level we're |
332 | really only interested in the first few |
333 | bits, so here we set all the trailing |
334 | to-be-ignored bits to 1 so they don't |
335 | affect the value > limit[length] |
336 | comparison. */ |
337 | limit[i] = (pp << (maxLen - i)) - 1; |
338 | pp <<= 1; |
339 | base[i+1] = pp-(t += temp[i]); |
340 | } |
341 | limit[maxLen+1] = INT_MAX; /* Sentinal value for |
342 | * reading next sym. */ |
343 | limit[maxLen] = pp+temp[maxLen]-1; |
344 | base[minLen] = 0; |
345 | } |
346 | /* We've finished reading and digesting the block header. Now |
347 | read this block's Huffman coded symbols from the file and |
348 | undo the Huffman coding and run length encoding, saving the |
349 | result into dbuf[dbufCount++] = uc */ |
350 | |
351 | /* Initialize symbol occurrence counters and symbol Move To |
352 | * Front table */ |
353 | for (i = 0; i < 256; i++) { |
354 | byteCount[i] = 0; |
355 | mtfSymbol[i] = (unsigned char)i; |
356 | } |
357 | /* Loop through compressed symbols. */ |
358 | runPos = dbufCount = symCount = selector = 0; |
359 | for (;;) { |
360 | /* Determine which Huffman coding group to use. */ |
361 | if (!(symCount--)) { |
362 | symCount = GROUP_SIZE-1; |
363 | if (selector >= nSelectors) |
364 | return RETVAL_DATA_ERROR; |
365 | hufGroup = bd->groups+selectors[selector++]; |
366 | base = hufGroup->base-1; |
367 | limit = hufGroup->limit-1; |
368 | } |
369 | /* Read next Huffman-coded symbol. */ |
370 | /* Note: It is far cheaper to read maxLen bits and |
371 | back up than it is to read minLen bits and then an |
372 | additional bit at a time, testing as we go. |
373 | Because there is a trailing last block (with file |
374 | CRC), there is no danger of the overread causing an |
375 | unexpected EOF for a valid compressed file. As a |
376 | further optimization, we do the read inline |
377 | (falling back to a call to get_bits if the buffer |
378 | runs dry). The following (up to got_huff_bits:) is |
379 | equivalent to j = get_bits(bd, hufGroup->maxLen); |
380 | */ |
381 | while (bd->inbufBitCount < hufGroup->maxLen) { |
382 | if (bd->inbufPos == bd->inbufCount) { |
383 | j = get_bits(bd, hufGroup->maxLen); |
384 | goto got_huff_bits; |
385 | } |
386 | bd->inbufBits = |
387 | (bd->inbufBits << 8)|bd->inbuf[bd->inbufPos++]; |
388 | bd->inbufBitCount += 8; |
389 | }; |
390 | bd->inbufBitCount -= hufGroup->maxLen; |
391 | j = (bd->inbufBits >> bd->inbufBitCount)& |
392 | ((1 << hufGroup->maxLen)-1); |
393 | got_huff_bits: |
394 | /* Figure how how many bits are in next symbol and |
395 | * unget extras */ |
396 | i = hufGroup->minLen; |
397 | while (j > limit[i]) |
398 | ++i; |
399 | bd->inbufBitCount += (hufGroup->maxLen - i); |
400 | /* Huffman decode value to get nextSym (with bounds checking) */ |
401 | if ((i > hufGroup->maxLen) |
402 | || (((unsigned)(j = (j>>(hufGroup->maxLen-i))-base[i])) |
403 | >= MAX_SYMBOLS)) |
404 | return RETVAL_DATA_ERROR; |
405 | nextSym = hufGroup->permute[j]; |
406 | /* We have now decoded the symbol, which indicates |
407 | either a new literal byte, or a repeated run of the |
408 | most recent literal byte. First, check if nextSym |
409 | indicates a repeated run, and if so loop collecting |
410 | how many times to repeat the last literal. */ |
411 | if (((unsigned)nextSym) <= SYMBOL_RUNB) { /* RUNA or RUNB */ |
412 | /* If this is the start of a new run, zero out |
413 | * counter */ |
414 | if (!runPos) { |
415 | runPos = 1; |
416 | t = 0; |
417 | } |
418 | /* Neat trick that saves 1 symbol: instead of |
419 | or-ing 0 or 1 at each bit position, add 1 |
420 | or 2 instead. For example, 1011 is 1 << 0 |
421 | + 1 << 1 + 2 << 2. 1010 is 2 << 0 + 2 << 1 |
422 | + 1 << 2. You can make any bit pattern |
423 | that way using 1 less symbol than the basic |
424 | or 0/1 method (except all bits 0, which |
425 | would use no symbols, but a run of length 0 |
426 | doesn't mean anything in this context). |
427 | Thus space is saved. */ |
428 | t += (runPos << nextSym); |
429 | /* +runPos if RUNA; +2*runPos if RUNB */ |
430 | |
431 | runPos <<= 1; |
432 | continue; |
433 | } |
434 | /* When we hit the first non-run symbol after a run, |
435 | we now know how many times to repeat the last |
436 | literal, so append that many copies to our buffer |
437 | of decoded symbols (dbuf) now. (The last literal |
438 | used is the one at the head of the mtfSymbol |
439 | array.) */ |
440 | if (runPos) { |
441 | runPos = 0; |
442 | if (dbufCount+t >= dbufSize) |
443 | return RETVAL_DATA_ERROR; |
444 | |
445 | uc = symToByte[mtfSymbol[0]]; |
446 | byteCount[uc] += t; |
447 | while (t--) |
448 | dbuf[dbufCount++] = uc; |
449 | } |
450 | /* Is this the terminating symbol? */ |
451 | if (nextSym > symTotal) |
452 | break; |
453 | /* At this point, nextSym indicates a new literal |
454 | character. Subtract one to get the position in the |
455 | MTF array at which this literal is currently to be |
456 | found. (Note that the result can't be -1 or 0, |
457 | because 0 and 1 are RUNA and RUNB. But another |
458 | instance of the first symbol in the mtf array, |
459 | position 0, would have been handled as part of a |
460 | run above. Therefore 1 unused mtf position minus 2 |
461 | non-literal nextSym values equals -1.) */ |
462 | if (dbufCount >= dbufSize) |
463 | return RETVAL_DATA_ERROR; |
464 | i = nextSym - 1; |
465 | uc = mtfSymbol[i]; |
466 | /* Adjust the MTF array. Since we typically expect to |
467 | *move only a small number of symbols, and are bound |
468 | *by 256 in any case, using memmove here would |
469 | *typically be bigger and slower due to function call |
470 | *overhead and other assorted setup costs. */ |
471 | do { |
472 | mtfSymbol[i] = mtfSymbol[i-1]; |
473 | } while (--i); |
474 | mtfSymbol[0] = uc; |
475 | uc = symToByte[uc]; |
476 | /* We have our literal byte. Save it into dbuf. */ |
477 | byteCount[uc]++; |
478 | dbuf[dbufCount++] = (unsigned int)uc; |
479 | } |
480 | /* At this point, we've read all the Huffman-coded symbols |
481 | (and repeated runs) for this block from the input stream, |
482 | and decoded them into the intermediate buffer. There are |
483 | dbufCount many decoded bytes in dbuf[]. Now undo the |
484 | Burrows-Wheeler transform on dbuf. See |
485 | http://dogma.net/markn/articles/bwt/bwt.htm |
486 | */ |
487 | /* Turn byteCount into cumulative occurrence counts of 0 to n-1. */ |
488 | j = 0; |
489 | for (i = 0; i < 256; i++) { |
490 | k = j+byteCount[i]; |
491 | byteCount[i] = j; |
492 | j = k; |
493 | } |
494 | /* Figure out what order dbuf would be in if we sorted it. */ |
495 | for (i = 0; i < dbufCount; i++) { |
496 | uc = (unsigned char)(dbuf[i] & 0xff); |
497 | dbuf[byteCount[uc]] |= (i << 8); |
498 | byteCount[uc]++; |
499 | } |
500 | /* Decode first byte by hand to initialize "previous" byte. |
501 | Note that it doesn't get output, and if the first three |
502 | characters are identical it doesn't qualify as a run (hence |
503 | writeRunCountdown = 5). */ |
504 | if (dbufCount) { |
505 | if (origPtr >= dbufCount) |
506 | return RETVAL_DATA_ERROR; |
507 | bd->writePos = dbuf[origPtr]; |
508 | bd->writeCurrent = (unsigned char)(bd->writePos&0xff); |
509 | bd->writePos >>= 8; |
510 | bd->writeRunCountdown = 5; |
511 | } |
512 | bd->writeCount = dbufCount; |
513 | |
514 | return RETVAL_OK; |
515 | } |
516 | |
517 | /* Undo burrows-wheeler transform on intermediate buffer to produce output. |
518 | If start_bunzip was initialized with out_fd =-1, then up to len bytes of |
519 | data are written to outbuf. Return value is number of bytes written or |
520 | error (all errors are negative numbers). If out_fd!=-1, outbuf and len |
521 | are ignored, data is written to out_fd and return is RETVAL_OK or error. |
522 | */ |
523 | |
524 | static int INIT read_bunzip(struct bunzip_data *bd, char *outbuf, int len) |
525 | { |
526 | const unsigned int *dbuf; |
527 | int pos, xcurrent, previous, gotcount; |
528 | |
529 | /* If last read was short due to end of file, return last block now */ |
530 | if (bd->writeCount < 0) |
531 | return bd->writeCount; |
532 | |
533 | gotcount = 0; |
534 | dbuf = bd->dbuf; |
535 | pos = bd->writePos; |
536 | xcurrent = bd->writeCurrent; |
537 | |
538 | /* We will always have pending decoded data to write into the output |
539 | buffer unless this is the very first call (in which case we haven't |
540 | Huffman-decoded a block into the intermediate buffer yet). */ |
541 | |
542 | if (bd->writeCopies) { |
543 | /* Inside the loop, writeCopies means extra copies (beyond 1) */ |
544 | --bd->writeCopies; |
545 | /* Loop outputting bytes */ |
546 | for (;;) { |
547 | /* If the output buffer is full, snapshot |
548 | * state and return */ |
549 | if (gotcount >= len) { |
550 | bd->writePos = pos; |
551 | bd->writeCurrent = xcurrent; |
552 | bd->writeCopies++; |
553 | return len; |
554 | } |
555 | /* Write next byte into output buffer, updating CRC */ |
556 | outbuf[gotcount++] = xcurrent; |
557 | bd->writeCRC = (((bd->writeCRC) << 8) |
558 | ^bd->crc32Table[((bd->writeCRC) >> 24) |
559 | ^xcurrent]); |
560 | /* Loop now if we're outputting multiple |
561 | * copies of this byte */ |
562 | if (bd->writeCopies) { |
563 | --bd->writeCopies; |
564 | continue; |
565 | } |
566 | decode_next_byte: |
567 | if (!bd->writeCount--) |
568 | break; |
569 | /* Follow sequence vector to undo |
570 | * Burrows-Wheeler transform */ |
571 | previous = xcurrent; |
572 | pos = dbuf[pos]; |
573 | xcurrent = pos&0xff; |
574 | pos >>= 8; |
575 | /* After 3 consecutive copies of the same |
576 | byte, the 4th is a repeat count. We count |
577 | down from 4 instead *of counting up because |
578 | testing for non-zero is faster */ |
579 | if (--bd->writeRunCountdown) { |
580 | if (xcurrent != previous) |
581 | bd->writeRunCountdown = 4; |
582 | } else { |
583 | /* We have a repeated run, this byte |
584 | * indicates the count */ |
585 | bd->writeCopies = xcurrent; |
586 | xcurrent = previous; |
587 | bd->writeRunCountdown = 5; |
588 | /* Sometimes there are just 3 bytes |
589 | * (run length 0) */ |
590 | if (!bd->writeCopies) |
591 | goto decode_next_byte; |
592 | /* Subtract the 1 copy we'd output |
593 | * anyway to get extras */ |
594 | --bd->writeCopies; |
595 | } |
596 | } |
597 | /* Decompression of this block completed successfully */ |
598 | bd->writeCRC = ~bd->writeCRC; |
599 | bd->totalCRC = ((bd->totalCRC << 1) | |
600 | (bd->totalCRC >> 31)) ^ bd->writeCRC; |
601 | /* If this block had a CRC error, force file level CRC error. */ |
602 | if (bd->writeCRC != bd->headerCRC) { |
603 | bd->totalCRC = bd->headerCRC+1; |
604 | return RETVAL_LAST_BLOCK; |
605 | } |
606 | } |
607 | |
608 | /* Refill the intermediate buffer by Huffman-decoding next |
609 | * block of input */ |
610 | /* (previous is just a convenient unused temp variable here) */ |
611 | previous = get_next_block(bd); |
612 | if (previous) { |
613 | bd->writeCount = previous; |
614 | return (previous != RETVAL_LAST_BLOCK) ? previous : gotcount; |
615 | } |
616 | bd->writeCRC = 0xffffffffUL; |
617 | pos = bd->writePos; |
618 | xcurrent = bd->writeCurrent; |
619 | goto decode_next_byte; |
620 | } |
621 | |
622 | static int INIT nofill(void *buf, unsigned int len) |
623 | { |
624 | return -1; |
625 | } |
626 | |
627 | /* Allocate the structure, read file header. If in_fd ==-1, inbuf must contain |
628 | a complete bunzip file (len bytes long). If in_fd!=-1, inbuf and len are |
629 | ignored, and data is read from file handle into temporary buffer. */ |
630 | static int INIT start_bunzip(struct bunzip_data **bdp, void *inbuf, int len, |
631 | int (*fill)(void*, unsigned int)) |
632 | { |
633 | struct bunzip_data *bd; |
634 | unsigned int i, j, c; |
635 | const unsigned int BZh0 = |
636 | (((unsigned int)'B') << 24)+(((unsigned int)'Z') << 16) |
637 | +(((unsigned int)'h') << 8)+(unsigned int)'0'; |
638 | |
639 | /* Figure out how much data to allocate */ |
640 | i = sizeof(struct bunzip_data); |
641 | |
642 | /* Allocate bunzip_data. Most fields initialize to zero. */ |
643 | bd = *bdp = malloc(i); |
644 | if (!bd) |
645 | return RETVAL_OUT_OF_MEMORY; |
646 | memset(bd, 0, sizeof(struct bunzip_data)); |
647 | /* Setup input buffer */ |
648 | bd->inbuf = inbuf; |
649 | bd->inbufCount = len; |
650 | if (fill != NULL) |
651 | bd->fill = fill; |
652 | else |
653 | bd->fill = nofill; |
654 | |
655 | /* Init the CRC32 table (big endian) */ |
656 | for (i = 0; i < 256; i++) { |
657 | c = i << 24; |
658 | for (j = 8; j; j--) |
659 | c = c&0x80000000 ? (c << 1)^0x04c11db7 : (c << 1); |
660 | bd->crc32Table[i] = c; |
661 | } |
662 | |
663 | /* Ensure that file starts with "BZh['1'-'9']." */ |
664 | i = get_bits(bd, 32); |
665 | if (((unsigned int)(i-BZh0-1)) >= 9) |
666 | return RETVAL_NOT_BZIP_DATA; |
667 | |
668 | /* Fourth byte (ascii '1'-'9'), indicates block size in units of 100k of |
669 | uncompressed data. Allocate intermediate buffer for block. */ |
670 | bd->dbufSize = 100000*(i-BZh0); |
671 | |
672 | bd->dbuf = large_malloc(bd->dbufSize * sizeof(int)); |
673 | if (!bd->dbuf) |
674 | return RETVAL_OUT_OF_MEMORY; |
675 | return RETVAL_OK; |
676 | } |
677 | |
678 | /* Example usage: decompress src_fd to dst_fd. (Stops at end of bzip2 data, |
679 | not end of file.) */ |
680 | STATIC int INIT bunzip2(unsigned char *buf, int len, |
681 | int(*fill)(void*, unsigned int), |
682 | int(*flush)(void*, unsigned int), |
683 | unsigned char *outbuf, |
684 | int *pos, |
685 | void(*error_fn)(char *x)) |
686 | { |
687 | struct bunzip_data *bd; |
688 | int i = -1; |
689 | unsigned char *inbuf; |
690 | |
691 | set_error_fn(error_fn); |
692 | if (flush) |
693 | outbuf = malloc(BZIP2_IOBUF_SIZE); |
694 | |
695 | if (!outbuf) { |
696 | error("Could not allocate output bufer"); |
697 | return RETVAL_OUT_OF_MEMORY; |
698 | } |
699 | if (buf) |
700 | inbuf = buf; |
701 | else |
702 | inbuf = malloc(BZIP2_IOBUF_SIZE); |
703 | if (!inbuf) { |
704 | error("Could not allocate input bufer"); |
705 | i = RETVAL_OUT_OF_MEMORY; |
706 | goto exit_0; |
707 | } |
708 | i = start_bunzip(&bd, inbuf, len, fill); |
709 | if (!i) { |
710 | for (;;) { |
711 | i = read_bunzip(bd, outbuf, BZIP2_IOBUF_SIZE); |
712 | if (i <= 0) |
713 | break; |
714 | if (!flush) |
715 | outbuf += i; |
716 | else |
717 | if (i != flush(outbuf, i)) { |
718 | i = RETVAL_UNEXPECTED_OUTPUT_EOF; |
719 | break; |
720 | } |
721 | } |
722 | } |
723 | /* Check CRC and release memory */ |
724 | if (i == RETVAL_LAST_BLOCK) { |
725 | if (bd->headerCRC != bd->totalCRC) |
726 | error("Data integrity error when decompressing."); |
727 | else |
728 | i = RETVAL_OK; |
729 | } else if (i == RETVAL_UNEXPECTED_OUTPUT_EOF) { |
730 | error("Compressed file ends unexpectedly"); |
731 | } |
732 | if (!bd) |
733 | goto exit_1; |
734 | if (bd->dbuf) |
735 | large_free(bd->dbuf); |
736 | if (pos) |
737 | *pos = bd->inbufPos; |
738 | free(bd); |
739 | exit_1: |
740 | if (!buf) |
741 | free(inbuf); |
742 | exit_0: |
743 | if (flush) |
744 | free(outbuf); |
745 | return i; |
746 | } |
747 | |
748 | #ifdef PREBOOT |
749 | STATIC int INIT decompress(unsigned char *buf, int len, |
750 | int(*fill)(void*, unsigned int), |
751 | int(*flush)(void*, unsigned int), |
752 | unsigned char *outbuf, |
753 | int *pos, |
754 | void(*error_fn)(char *x)) |
755 | { |
756 | return bunzip2(buf, len - 4, fill, flush, outbuf, pos, error_fn); |
757 | } |
758 | #endif |
759 |
Branches:
ben-wpan
ben-wpan-stefan
javiroman/ks7010
jz-2.6.34
jz-2.6.34-rc5
jz-2.6.34-rc6
jz-2.6.34-rc7
jz-2.6.35
jz-2.6.36
jz-2.6.37
jz-2.6.38
jz-2.6.39
jz-3.0
jz-3.1
jz-3.11
jz-3.12
jz-3.13
jz-3.15
jz-3.16
jz-3.18-dt
jz-3.2
jz-3.3
jz-3.4
jz-3.5
jz-3.6
jz-3.6-rc2-pwm
jz-3.9
jz-3.9-clk
jz-3.9-rc8
jz47xx
jz47xx-2.6.38
master
Tags:
od-2011-09-04
od-2011-09-18
v2.6.34-rc5
v2.6.34-rc6
v2.6.34-rc7
v3.9