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