diff options
Diffstat (limited to 'archival/libarchive/decompress_bunzip2.c')
| -rw-r--r-- | archival/libarchive/decompress_bunzip2.c | 822 |
1 files changed, 822 insertions, 0 deletions
diff --git a/archival/libarchive/decompress_bunzip2.c b/archival/libarchive/decompress_bunzip2.c new file mode 100644 index 000000000..4e46e6849 --- /dev/null +++ b/archival/libarchive/decompress_bunzip2.c @@ -0,0 +1,822 @@ +/* vi: set sw=4 ts=4: */ +/* Small bzip2 deflate implementation, by Rob Landley (rob@landley.net). + + Based on bzip2 decompression code by Julian R Seward (jseward@acm.org), + which also acknowledges contributions by Mike Burrows, David Wheeler, + Peter Fenwick, Alistair Moffat, Radford Neal, Ian H. Witten, + Robert Sedgewick, and Jon L. Bentley. + + Licensed under GPLv2 or later, see file LICENSE in this source tree. +*/ + +/* + Size and speed optimizations by Manuel Novoa III (mjn3@codepoet.org). + + More efficient reading of Huffman codes, a streamlined read_bunzip() + function, and various other tweaks. In (limited) tests, approximately + 20% faster than bzcat on x86 and about 10% faster on arm. + + Note that about 2/3 of the time is spent in read_bunzip() reversing + the Burrows-Wheeler transformation. Much of that time is delay + resulting from cache misses. + + (2010 update by vda: profiled "bzcat <84mbyte.bz2 >/dev/null" + on x86-64 CPU with L2 > 1M: get_next_block is hotter than read_bunzip: + %time seconds calls function + 71.01 12.69 444 get_next_block + 28.65 5.12 93065 read_bunzip + 00.22 0.04 7736490 get_bits + 00.11 0.02 47 dealloc_bunzip + 00.00 0.00 93018 full_write + ...) + + + I would ask that anyone benefiting from this work, especially those + using it in commercial products, consider making a donation to my local + non-profit hospice organization (www.hospiceacadiana.com) in the name of + the woman I loved, Toni W. Hagan, who passed away Feb. 12, 2003. + + Manuel + */ + +#include "libbb.h" +#include "archive.h" + +/* Constants for Huffman coding */ +#define MAX_GROUPS 6 +#define GROUP_SIZE 50 /* 64 would have been more efficient */ +#define MAX_HUFCODE_BITS 20 /* Longest Huffman code allowed */ +#define MAX_SYMBOLS 258 /* 256 literals + RUNA + RUNB */ +#define SYMBOL_RUNA 0 +#define SYMBOL_RUNB 1 + +/* Status return values */ +#define RETVAL_OK 0 +#define RETVAL_LAST_BLOCK (-1) +#define RETVAL_NOT_BZIP_DATA (-2) +#define RETVAL_UNEXPECTED_INPUT_EOF (-3) +#define RETVAL_SHORT_WRITE (-4) +#define RETVAL_DATA_ERROR (-5) +#define RETVAL_OUT_OF_MEMORY (-6) +#define RETVAL_OBSOLETE_INPUT (-7) + +/* Other housekeeping constants */ +#define IOBUF_SIZE 4096 + +/* This is what we know about each Huffman coding group */ +struct group_data { + /* We have an extra slot at the end of limit[] for a sentinel value. */ + int limit[MAX_HUFCODE_BITS+1], base[MAX_HUFCODE_BITS], permute[MAX_SYMBOLS]; + int minLen, maxLen; +}; + +/* Structure holding all the housekeeping data, including IO buffers and + * memory that persists between calls to bunzip + * Found the most used member: + * cat this_file.c | sed -e 's/"/ /g' -e "s/'/ /g" | xargs -n1 \ + * | grep 'bd->' | sed 's/^.*bd->/bd->/' | sort | $PAGER + * and moved it (inbufBitCount) to offset 0. + */ +struct bunzip_data { + /* I/O tracking data (file handles, buffers, positions, etc.) */ + unsigned inbufBitCount, inbufBits; + int in_fd, out_fd, inbufCount, inbufPos /*, outbufPos*/; + uint8_t *inbuf /*,*outbuf*/; + + /* State for interrupting output loop */ + int writeCopies, writePos, writeRunCountdown, writeCount; + int writeCurrent; /* actually a uint8_t */ + + /* The CRC values stored in the block header and calculated from the data */ + uint32_t headerCRC, totalCRC, writeCRC; + + /* Intermediate buffer and its size (in bytes) */ + uint32_t *dbuf; + unsigned dbufSize; + + /* For I/O error handling */ + jmp_buf jmpbuf; + + /* Big things go last (register-relative addressing can be larger for big offsets) */ + uint32_t crc32Table[256]; + uint8_t selectors[32768]; /* nSelectors=15 bits */ + struct group_data groups[MAX_GROUPS]; /* Huffman coding tables */ +}; +/* typedef struct bunzip_data bunzip_data; -- done in .h file */ + + +/* Return the next nnn bits of input. All reads from the compressed input + are done through this function. All reads are big endian */ +static unsigned get_bits(bunzip_data *bd, int bits_wanted) +{ + unsigned bits = 0; + /* Cache bd->inbufBitCount in a CPU register (hopefully): */ + int bit_count = bd->inbufBitCount; + + /* If we need to get more data from the byte buffer, do so. (Loop getting + one byte at a time to enforce endianness and avoid unaligned access.) */ + while (bit_count < bits_wanted) { + + /* If we need to read more data from file into byte buffer, do so */ + if (bd->inbufPos == bd->inbufCount) { + /* if "no input fd" case: in_fd == -1, read fails, we jump */ + bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE); + if (bd->inbufCount <= 0) + longjmp(bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF); + bd->inbufPos = 0; + } + + /* Avoid 32-bit overflow (dump bit buffer to top of output) */ + if (bit_count >= 24) { + bits = bd->inbufBits & ((1 << bit_count) - 1); + bits_wanted -= bit_count; + bits <<= bits_wanted; + bit_count = 0; + } + + /* Grab next 8 bits of input from buffer. */ + bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++]; + bit_count += 8; + } + + /* Calculate result */ + bit_count -= bits_wanted; + bd->inbufBitCount = bit_count; + bits |= (bd->inbufBits >> bit_count) & ((1 << bits_wanted) - 1); + + return bits; +} + +/* Unpacks the next block and sets up for the inverse Burrows-Wheeler step. */ +static int get_next_block(bunzip_data *bd) +{ + struct group_data *hufGroup; + int dbufCount, dbufSize, groupCount, *base, *limit, selector, + i, j, t, runPos, symCount, symTotal, nSelectors, byteCount[256]; + int runCnt = runCnt; /* for compiler */ + uint8_t uc, symToByte[256], mtfSymbol[256], *selectors; + uint32_t *dbuf; + unsigned origPtr; + + dbuf = bd->dbuf; + dbufSize = bd->dbufSize; + selectors = bd->selectors; + +/* In bbox, we are ok with aborting through setjmp which is set up in start_bunzip */ +#if 0 + /* Reset longjmp I/O error handling */ + i = setjmp(bd->jmpbuf); + if (i) return i; +#endif + + /* Read in header signature and CRC, then validate signature. + (last block signature means CRC is for whole file, return now) */ + i = get_bits(bd, 24); + j = get_bits(bd, 24); + bd->headerCRC = get_bits(bd, 32); + if ((i == 0x177245) && (j == 0x385090)) return RETVAL_LAST_BLOCK; + if ((i != 0x314159) || (j != 0x265359)) return RETVAL_NOT_BZIP_DATA; + + /* We can add support for blockRandomised if anybody complains. There was + some code for this in busybox 1.0.0-pre3, but nobody ever noticed that + it didn't actually work. */ + if (get_bits(bd, 1)) return RETVAL_OBSOLETE_INPUT; + origPtr = get_bits(bd, 24); + if ((int)origPtr > dbufSize) return RETVAL_DATA_ERROR; + + /* mapping table: if some byte values are never used (encoding things + like ascii text), the compression code removes the gaps to have fewer + symbols to deal with, and writes a sparse bitfield indicating which + values were present. We make a translation table to convert the symbols + back to the corresponding bytes. */ + symTotal = 0; + i = 0; + t = get_bits(bd, 16); + do { + if (t & (1 << 15)) { + unsigned inner_map = get_bits(bd, 16); + do { + if (inner_map & (1 << 15)) + symToByte[symTotal++] = i; + inner_map <<= 1; + i++; + } while (i & 15); + i -= 16; + } + t <<= 1; + i += 16; + } while (i < 256); + + /* How many different Huffman coding groups does this block use? */ + groupCount = get_bits(bd, 3); + if (groupCount < 2 || groupCount > MAX_GROUPS) + return RETVAL_DATA_ERROR; + + /* nSelectors: Every GROUP_SIZE many symbols we select a new Huffman coding + group. Read in the group selector list, which is stored as MTF encoded + bit runs. (MTF=Move To Front, as each value is used it's moved to the + start of the list.) */ + for (i = 0; i < groupCount; i++) + mtfSymbol[i] = i; + nSelectors = get_bits(bd, 15); + if (!nSelectors) + return RETVAL_DATA_ERROR; + for (i = 0; i < nSelectors; i++) { + uint8_t tmp_byte; + /* Get next value */ + int n = 0; + while (get_bits(bd, 1)) { + if (n >= groupCount) return RETVAL_DATA_ERROR; + n++; + } + /* Decode MTF to get the next selector */ + tmp_byte = mtfSymbol[n]; + while (--n >= 0) + mtfSymbol[n + 1] = mtfSymbol[n]; + mtfSymbol[0] = selectors[i] = tmp_byte; + } + + /* Read the Huffman coding tables for each group, which code for symTotal + literal symbols, plus two run symbols (RUNA, RUNB) */ + symCount = symTotal + 2; + for (j = 0; j < groupCount; j++) { + uint8_t length[MAX_SYMBOLS]; + /* 8 bits is ALMOST enough for temp[], see below */ + unsigned temp[MAX_HUFCODE_BITS+1]; + int minLen, maxLen, pp, len_m1; + + /* Read Huffman code lengths for each symbol. They're stored in + a way similar to mtf; record a starting value for the first symbol, + and an offset from the previous value for every symbol after that. + (Subtracting 1 before the loop and then adding it back at the end is + an optimization that makes the test inside the loop simpler: symbol + length 0 becomes negative, so an unsigned inequality catches it.) */ + len_m1 = get_bits(bd, 5) - 1; + for (i = 0; i < symCount; i++) { + for (;;) { + int two_bits; + if ((unsigned)len_m1 > (MAX_HUFCODE_BITS-1)) + return RETVAL_DATA_ERROR; + + /* If first bit is 0, stop. Else second bit indicates whether + to increment or decrement the value. Optimization: grab 2 + bits and unget the second if the first was 0. */ + two_bits = get_bits(bd, 2); + if (two_bits < 2) { + bd->inbufBitCount++; + break; + } + + /* Add one if second bit 1, else subtract 1. Avoids if/else */ + len_m1 += (((two_bits+1) & 2) - 1); + } + + /* Correct for the initial -1, to get the final symbol length */ + length[i] = len_m1 + 1; + } + + /* Find largest and smallest lengths in this group */ + minLen = maxLen = length[0]; + for (i = 1; i < symCount; i++) { + if (length[i] > maxLen) maxLen = length[i]; + else if (length[i] < minLen) minLen = length[i]; + } + + /* Calculate permute[], base[], and limit[] tables from length[]. + * + * permute[] is the lookup table for converting Huffman coded symbols + * into decoded symbols. base[] is the amount to subtract from the + * value of a Huffman symbol of a given length when using permute[]. + * + * limit[] indicates the largest numerical value a symbol with a given + * number of bits can have. This is how the Huffman codes can vary in + * length: each code with a value>limit[length] needs another bit. + */ + hufGroup = bd->groups + j; + hufGroup->minLen = minLen; + hufGroup->maxLen = maxLen; + + /* Note that minLen can't be smaller than 1, so we adjust the base + and limit array pointers so we're not always wasting the first + entry. We do this again when using them (during symbol decoding). */ + base = hufGroup->base - 1; + limit = hufGroup->limit - 1; + + /* Calculate permute[]. Concurently, initialize temp[] and limit[]. */ + pp = 0; + for (i = minLen; i <= maxLen; i++) { + int k; + temp[i] = limit[i] = 0; + for (k = 0; k < symCount; k++) + if (length[k] == i) + hufGroup->permute[pp++] = k; + } + + /* Count symbols coded for at each bit length */ + /* NB: in pathological cases, temp[8] can end ip being 256. + * That's why uint8_t is too small for temp[]. */ + for (i = 0; i < symCount; i++) temp[length[i]]++; + + /* Calculate limit[] (the largest symbol-coding value at each bit + * length, which is (previous limit<<1)+symbols at this level), and + * base[] (number of symbols to ignore at each bit length, which is + * limit minus the cumulative count of symbols coded for already). */ + pp = t = 0; + for (i = minLen; i < maxLen;) { + unsigned temp_i = temp[i]; + + pp += temp_i; + + /* We read the largest possible symbol size and then unget bits + after determining how many we need, and those extra bits could + be set to anything. (They're noise from future symbols.) At + each level we're really only interested in the first few bits, + so here we set all the trailing to-be-ignored bits to 1 so they + don't affect the value>limit[length] comparison. */ + limit[i] = (pp << (maxLen - i)) - 1; + pp <<= 1; + t += temp_i; + base[++i] = pp - t; + } + limit[maxLen] = pp + temp[maxLen] - 1; + limit[maxLen+1] = INT_MAX; /* Sentinel value for reading next sym. */ + base[minLen] = 0; + } + + /* We've finished reading and digesting the block header. Now read this + block's Huffman coded symbols from the file and undo the Huffman coding + and run length encoding, saving the result into dbuf[dbufCount++] = uc */ + + /* Initialize symbol occurrence counters and symbol Move To Front table */ + /*memset(byteCount, 0, sizeof(byteCount)); - smaller, but slower */ + for (i = 0; i < 256; i++) { + byteCount[i] = 0; + mtfSymbol[i] = (uint8_t)i; + } + + /* Loop through compressed symbols. */ + + runPos = dbufCount = selector = 0; + for (;;) { + int nextSym; + + /* Fetch next Huffman coding group from list. */ + symCount = GROUP_SIZE - 1; + if (selector >= nSelectors) return RETVAL_DATA_ERROR; + hufGroup = bd->groups + selectors[selector++]; + base = hufGroup->base - 1; + limit = hufGroup->limit - 1; + + continue_this_group: + /* Read next Huffman-coded symbol. */ + + /* Note: It is far cheaper to read maxLen bits and back up than it is + to read minLen bits and then add additional bit at a time, testing + as we go. Because there is a trailing last block (with file CRC), + there is no danger of the overread causing an unexpected EOF for a + valid compressed file. + */ + if (1) { + /* As a further optimization, we do the read inline + (falling back to a call to get_bits if the buffer runs dry). + */ + int new_cnt; + while ((new_cnt = bd->inbufBitCount - hufGroup->maxLen) < 0) { + /* bd->inbufBitCount < hufGroup->maxLen */ + if (bd->inbufPos == bd->inbufCount) { + nextSym = get_bits(bd, hufGroup->maxLen); + goto got_huff_bits; + } + bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++]; + bd->inbufBitCount += 8; + }; + bd->inbufBitCount = new_cnt; /* "bd->inbufBitCount -= hufGroup->maxLen;" */ + nextSym = (bd->inbufBits >> new_cnt) & ((1 << hufGroup->maxLen) - 1); + got_huff_bits: ; + } else { /* unoptimized equivalent */ + nextSym = get_bits(bd, hufGroup->maxLen); + } + /* Figure how many bits are in next symbol and unget extras */ + i = hufGroup->minLen; + while (nextSym > limit[i]) ++i; + j = hufGroup->maxLen - i; + if (j < 0) + return RETVAL_DATA_ERROR; + bd->inbufBitCount += j; + + /* Huffman decode value to get nextSym (with bounds checking) */ + nextSym = (nextSym >> j) - base[i]; + if ((unsigned)nextSym >= MAX_SYMBOLS) + return RETVAL_DATA_ERROR; + nextSym = hufGroup->permute[nextSym]; + + /* We have now decoded the symbol, which indicates either a new literal + byte, or a repeated run of the most recent literal byte. First, + check if nextSym indicates a repeated run, and if so loop collecting + how many times to repeat the last literal. */ + if ((unsigned)nextSym <= SYMBOL_RUNB) { /* RUNA or RUNB */ + + /* If this is the start of a new run, zero out counter */ + if (runPos == 0) { + runPos = 1; + runCnt = 0; + } + + /* Neat trick that saves 1 symbol: instead of or-ing 0 or 1 at + each bit position, add 1 or 2 instead. For example, + 1011 is 1<<0 + 1<<1 + 2<<2. 1010 is 2<<0 + 2<<1 + 1<<2. + You can make any bit pattern that way using 1 less symbol than + the basic or 0/1 method (except all bits 0, which would use no + symbols, but a run of length 0 doesn't mean anything in this + context). Thus space is saved. */ + runCnt += (runPos << nextSym); /* +runPos if RUNA; +2*runPos if RUNB */ + if (runPos < dbufSize) runPos <<= 1; + goto end_of_huffman_loop; + } + + /* When we hit the first non-run symbol after a run, we now know + how many times to repeat the last literal, so append that many + copies to our buffer of decoded symbols (dbuf) now. (The last + literal used is the one at the head of the mtfSymbol array.) */ + if (runPos != 0) { + uint8_t tmp_byte; + if (dbufCount + runCnt >= dbufSize) return RETVAL_DATA_ERROR; + tmp_byte = symToByte[mtfSymbol[0]]; + byteCount[tmp_byte] += runCnt; + while (--runCnt >= 0) dbuf[dbufCount++] = (uint32_t)tmp_byte; + runPos = 0; + } + + /* Is this the terminating symbol? */ + if (nextSym > symTotal) break; + + /* At this point, nextSym indicates a new literal character. Subtract + one to get the position in the MTF array at which this literal is + currently to be found. (Note that the result can't be -1 or 0, + because 0 and 1 are RUNA and RUNB. But another instance of the + first symbol in the mtf array, position 0, would have been handled + as part of a run above. Therefore 1 unused mtf position minus + 2 non-literal nextSym values equals -1.) */ + if (dbufCount >= dbufSize) return RETVAL_DATA_ERROR; + i = nextSym - 1; + uc = mtfSymbol[i]; + + /* Adjust the MTF array. Since we typically expect to move only a + * small number of symbols, and are bound by 256 in any case, using + * memmove here would typically be bigger and slower due to function + * call overhead and other assorted setup costs. */ + do { + mtfSymbol[i] = mtfSymbol[i-1]; + } while (--i); + mtfSymbol[0] = uc; + uc = symToByte[uc]; + + /* We have our literal byte. Save it into dbuf. */ + byteCount[uc]++; + dbuf[dbufCount++] = (uint32_t)uc; + + /* Skip group initialization if we're not done with this group. Done + * this way to avoid compiler warning. */ + end_of_huffman_loop: + if (--symCount >= 0) goto continue_this_group; + } + + /* At this point, we've read all the Huffman-coded symbols (and repeated + runs) for this block from the input stream, and decoded them into the + intermediate buffer. There are dbufCount many decoded bytes in dbuf[]. + Now undo the Burrows-Wheeler transform on dbuf. + See http://dogma.net/markn/articles/bwt/bwt.htm + */ + + /* Turn byteCount into cumulative occurrence counts of 0 to n-1. */ + j = 0; + for (i = 0; i < 256; i++) { + int tmp_count = j + byteCount[i]; + byteCount[i] = j; + j = tmp_count; + } + + /* Figure out what order dbuf would be in if we sorted it. */ + for (i = 0; i < dbufCount; i++) { + uint8_t tmp_byte = (uint8_t)dbuf[i]; + int tmp_count = byteCount[tmp_byte]; + dbuf[tmp_count] |= (i << 8); + byteCount[tmp_byte] = tmp_count + 1; + } + + /* Decode first byte by hand to initialize "previous" byte. Note that it + doesn't get output, and if the first three characters are identical + it doesn't qualify as a run (hence writeRunCountdown=5). */ + if (dbufCount) { + uint32_t tmp; + if ((int)origPtr >= dbufCount) return RETVAL_DATA_ERROR; + tmp = dbuf[origPtr]; + bd->writeCurrent = (uint8_t)tmp; + bd->writePos = (tmp >> 8); + bd->writeRunCountdown = 5; + } + bd->writeCount = dbufCount; + + return RETVAL_OK; +} + +/* Undo Burrows-Wheeler transform on intermediate buffer to produce output. + If start_bunzip was initialized with out_fd=-1, then up to len bytes of + data are written to outbuf. Return value is number of bytes written or + error (all errors are negative numbers). If out_fd!=-1, outbuf and len + are ignored, data is written to out_fd and return is RETVAL_OK or error. + + NB: read_bunzip returns < 0 on error, or the number of *unfilled* bytes + in outbuf. IOW: on EOF returns len ("all bytes are not filled"), not 0. + (Why? This allows to get rid of one local variable) +*/ +int FAST_FUNC read_bunzip(bunzip_data *bd, char *outbuf, int len) +{ + const uint32_t *dbuf; + int pos, current, previous; + uint32_t CRC; + + /* If we already have error/end indicator, return it */ + if (bd->writeCount < 0) + return bd->writeCount; + + dbuf = bd->dbuf; + + /* Register-cached state (hopefully): */ + pos = bd->writePos; + current = bd->writeCurrent; + CRC = bd->writeCRC; /* small loss on x86-32 (not enough regs), win on x86-64 */ + + /* We will always have pending decoded data to write into the output + buffer unless this is the very first call (in which case we haven't + Huffman-decoded a block into the intermediate buffer yet). */ + if (bd->writeCopies) { + + dec_writeCopies: + /* Inside the loop, writeCopies means extra copies (beyond 1) */ + --bd->writeCopies; + + /* Loop outputting bytes */ + for (;;) { + + /* If the output buffer is full, save cached state and return */ + if (--len < 0) { + /* Unlikely branch. + * Use of "goto" instead of keeping code here + * helps compiler to realize this. */ + goto outbuf_full; + } + + /* Write next byte into output buffer, updating CRC */ + *outbuf++ = current; + CRC = (CRC << 8) ^ bd->crc32Table[(CRC >> 24) ^ current]; + + /* Loop now if we're outputting multiple copies of this byte */ + if (bd->writeCopies) { + /* Unlikely branch */ + /*--bd->writeCopies;*/ + /*continue;*/ + /* Same, but (ab)using other existing --writeCopies operation + * (and this if() compiles into just test+branch pair): */ + goto dec_writeCopies; + } + decode_next_byte: + if (--bd->writeCount < 0) + break; /* input block is fully consumed, need next one */ + + /* Follow sequence vector to undo Burrows-Wheeler transform */ + previous = current; + pos = dbuf[pos]; + current = (uint8_t)pos; + pos >>= 8; + + /* After 3 consecutive copies of the same byte, the 4th + * is a repeat count. We count down from 4 instead + * of counting up because testing for non-zero is faster */ + if (--bd->writeRunCountdown != 0) { + if (current != previous) + bd->writeRunCountdown = 4; + } else { + /* Unlikely branch */ + /* We have a repeated run, this byte indicates the count */ + bd->writeCopies = current; + current = previous; + bd->writeRunCountdown = 5; + + /* Sometimes there are just 3 bytes (run length 0) */ + if (!bd->writeCopies) goto decode_next_byte; + + /* Subtract the 1 copy we'd output anyway to get extras */ + --bd->writeCopies; + } + } /* for(;;) */ + + /* Decompression of this input block completed successfully */ + bd->writeCRC = CRC = ~CRC; + bd->totalCRC = ((bd->totalCRC << 1) | (bd->totalCRC >> 31)) ^ CRC; + + /* If this block had a CRC error, force file level CRC error */ + if (CRC != bd->headerCRC) { + bd->totalCRC = bd->headerCRC + 1; + return RETVAL_LAST_BLOCK; + } + } + + /* Refill the intermediate buffer by Huffman-decoding next block of input */ + { + int r = get_next_block(bd); + if (r) { /* error/end */ + bd->writeCount = r; + return (r != RETVAL_LAST_BLOCK) ? r : len; + } + } + + CRC = ~0; + pos = bd->writePos; + current = bd->writeCurrent; + goto decode_next_byte; + + outbuf_full: + /* Output buffer is full, save cached state and return */ + bd->writePos = pos; + bd->writeCurrent = current; + bd->writeCRC = CRC; + + bd->writeCopies++; + + return 0; +} + +/* Allocate the structure, read file header. If in_fd==-1, inbuf must contain + a complete bunzip file (len bytes long). If in_fd!=-1, inbuf and len are + ignored, and data is read from file handle into temporary buffer. */ + +/* Because bunzip2 is used for help text unpacking, and because bb_show_usage() + should work for NOFORK applets too, we must be extremely careful to not leak + any allocations! */ +int FAST_FUNC start_bunzip(bunzip_data **bdp, int in_fd, + const void *inbuf, int len) +{ + bunzip_data *bd; + unsigned i; + enum { + BZh0 = ('B' << 24) + ('Z' << 16) + ('h' << 8) + '0', + h0 = ('h' << 8) + '0', + }; + + /* Figure out how much data to allocate */ + i = sizeof(bunzip_data); + if (in_fd != -1) i += IOBUF_SIZE; + + /* Allocate bunzip_data. Most fields initialize to zero. */ + bd = *bdp = xzalloc(i); + + /* Setup input buffer */ + bd->in_fd = in_fd; + if (-1 == in_fd) { + /* in this case, bd->inbuf is read-only */ + bd->inbuf = (void*)inbuf; /* cast away const-ness */ + } else { + bd->inbuf = (uint8_t*)(bd + 1); + memcpy(bd->inbuf, inbuf, len); + } + bd->inbufCount = len; + + /* Init the CRC32 table (big endian) */ + crc32_filltable(bd->crc32Table, 1); + + /* Setup for I/O error handling via longjmp */ + i = setjmp(bd->jmpbuf); + if (i) return i; + + /* Ensure that file starts with "BZh['1'-'9']." */ + /* Update: now caller verifies 1st two bytes, makes .gz/.bz2 + * integration easier */ + /* was: */ + /* i = get_bits(bd, 32); */ + /* if ((unsigned)(i - BZh0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA; */ + i = get_bits(bd, 16); + if ((unsigned)(i - h0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA; + + /* Fourth byte (ascii '1'-'9') indicates block size in units of 100k of + uncompressed data. Allocate intermediate buffer for block. */ + /* bd->dbufSize = 100000 * (i - BZh0); */ + bd->dbufSize = 100000 * (i - h0); + + /* Cannot use xmalloc - may leak bd in NOFORK case! */ + bd->dbuf = malloc_or_warn(bd->dbufSize * sizeof(bd->dbuf[0])); + if (!bd->dbuf) { + free(bd); + xfunc_die(); + } + return RETVAL_OK; +} + +void FAST_FUNC dealloc_bunzip(bunzip_data *bd) +{ + free(bd->dbuf); + free(bd); +} + + +/* Decompress src_fd to dst_fd. Stops at end of bzip data, not end of file. */ +IF_DESKTOP(long long) int FAST_FUNC +unpack_bz2_stream(int src_fd, int dst_fd) +{ + IF_DESKTOP(long long total_written = 0;) + bunzip_data *bd; + char *outbuf; + int i; + unsigned len; + + outbuf = xmalloc(IOBUF_SIZE); + len = 0; + while (1) { /* "Process one BZ... stream" loop */ + + i = start_bunzip(&bd, src_fd, outbuf + 2, len); + + if (i == 0) { + while (1) { /* "Produce some output bytes" loop */ + i = read_bunzip(bd, outbuf, IOBUF_SIZE); + if (i < 0) /* error? */ + break; + i = IOBUF_SIZE - i; /* number of bytes produced */ + if (i == 0) /* EOF? */ + break; + if (i != full_write(dst_fd, outbuf, i)) { + bb_error_msg("short write"); + i = RETVAL_SHORT_WRITE; + goto release_mem; + } + IF_DESKTOP(total_written += i;) + } + } + + if (i != RETVAL_LAST_BLOCK) { + bb_error_msg("bunzip error %d", i); + break; + } + if (bd->headerCRC != bd->totalCRC) { + bb_error_msg("CRC error"); + break; + } + + /* Successfully unpacked one BZ stream */ + i = RETVAL_OK; + + /* Do we have "BZ..." after last processed byte? + * pbzip2 (parallelized bzip2) produces such files. + */ + len = bd->inbufCount - bd->inbufPos; + memcpy(outbuf, &bd->inbuf[bd->inbufPos], len); + if (len < 2) { + if (safe_read(src_fd, outbuf + len, 2 - len) != 2 - len) + break; + len = 2; + } + if (*(uint16_t*)outbuf != BZIP2_MAGIC) /* "BZ"? */ + break; + dealloc_bunzip(bd); + len -= 2; + } + + release_mem: + dealloc_bunzip(bd); + free(outbuf); + + return i ? i : IF_DESKTOP(total_written) + 0; +} + +IF_DESKTOP(long long) int FAST_FUNC +unpack_bz2_stream_prime(int src_fd, int dst_fd) +{ + uint16_t magic2; + xread(src_fd, &magic2, 2); + if (magic2 != BZIP2_MAGIC) { + bb_error_msg_and_die("invalid magic"); + } + return unpack_bz2_stream(src_fd, dst_fd); +} + +#ifdef TESTING + +static char *const bunzip_errors[] = { + NULL, "Bad file checksum", "Not bzip data", + "Unexpected input EOF", "Unexpected output EOF", "Data error", + "Out of memory", "Obsolete (pre 0.9.5) bzip format not supported" +}; + +/* Dumb little test thing, decompress stdin to stdout */ +int main(int argc, char **argv) +{ + int i; + char c; + + int i = unpack_bz2_stream_prime(0, 1); + if (i < 0) + fprintf(stderr, "%s\n", bunzip_errors[-i]); + else if (read(STDIN_FILENO, &c, 1)) + fprintf(stderr, "Trailing garbage ignored\n"); + return -i; +} +#endif |