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bc22c17e AK |
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 | ||
b1af4315 PL |
48 | #ifdef STATIC |
49 | #define PREBOOT | |
50 | #else | |
bc22c17e | 51 | #include <linux/decompress/bunzip2.h> |
9e5cf0ca | 52 | #include <linux/slab.h> |
b1af4315 | 53 | #endif /* STATIC */ |
bc22c17e AK |
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 */ | |
dd21e9bd PB |
110 | int byteCount[256]; |
111 | unsigned char symToByte[256], mtfSymbol[256]; | |
bc22c17e AK |
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, | |
dd21e9bd PB |
163 | i, j, k, t, runPos, symCount, symTotal, nSelectors, *byteCount; |
164 | unsigned char uc, *symToByte, *mtfSymbol, *selectors; | |
bc22c17e AK |
165 | unsigned int *dbuf, origPtr; |
166 | ||
167 | dbuf = bd->dbuf; | |
168 | dbufSize = bd->dbufSize; | |
169 | selectors = bd->selectors; | |
dd21e9bd PB |
170 | byteCount = bd->byteCount; |
171 | symToByte = bd->symToByte; | |
172 | mtfSymbol = bd->mtfSymbol; | |
bc22c17e AK |
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; | |
af901ca1 | 306 | /* Calculate permute[]. Concurrently, initialize |
bc22c17e AK |
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); | |
d4529862 PL |
644 | if (!bd) |
645 | return RETVAL_OUT_OF_MEMORY; | |
bc22c17e AK |
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)); | |
d4529862 PL |
673 | if (!bd->dbuf) |
674 | return RETVAL_OUT_OF_MEMORY; | |
bc22c17e AK |
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); | |
b1af4315 | 694 | |
bc22c17e AK |
695 | if (!outbuf) { |
696 | error("Could not allocate output bufer"); | |
d4529862 | 697 | return RETVAL_OUT_OF_MEMORY; |
bc22c17e AK |
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"); | |
d4529862 | 705 | i = RETVAL_OUT_OF_MEMORY; |
bc22c17e AK |
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 | } | |
d4529862 PL |
732 | if (!bd) |
733 | goto exit_1; | |
bc22c17e AK |
734 | if (bd->dbuf) |
735 | large_free(bd->dbuf); | |
736 | if (pos) | |
737 | *pos = bd->inbufPos; | |
738 | free(bd); | |
d4529862 | 739 | exit_1: |
bc22c17e AK |
740 | if (!buf) |
741 | free(inbuf); | |
742 | exit_0: | |
743 | if (flush) | |
744 | free(outbuf); | |
745 | return i; | |
746 | } | |
747 | ||
b1af4315 PL |
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 |