[2725] | 1 | /* vi: set sw=4 ts=4: */
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| 2 | /* Small bzip2 deflate implementation, by Rob Landley (rob@landley.net).
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| 3 |
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| 4 | Based on bzip2 decompression code by Julian R Seward (jseward@acm.org),
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| 5 | which also acknowledges contributions by Mike Burrows, David Wheeler,
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| 6 | Peter Fenwick, Alistair Moffat, Radford Neal, Ian H. Witten,
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| 7 | Robert Sedgewick, and Jon L. Bentley.
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| 8 |
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| 9 | Licensed under GPLv2 or later, see file LICENSE in this source tree.
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| 10 | */
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| 11 |
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| 12 | /*
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| 13 | Size and speed optimizations by Manuel Novoa III (mjn3@codepoet.org).
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| 14 |
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| 15 | More efficient reading of Huffman codes, a streamlined read_bunzip()
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| 16 | function, and various other tweaks. In (limited) tests, approximately
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| 17 | 20% faster than bzcat on x86 and about 10% faster on arm.
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| 18 |
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| 19 | Note that about 2/3 of the time is spent in read_bunzip() reversing
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| 20 | the Burrows-Wheeler transformation. Much of that time is delay
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| 21 | resulting from cache misses.
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| 22 |
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| 23 | (2010 update by vda: profiled "bzcat <84mbyte.bz2 >/dev/null"
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| 24 | on x86-64 CPU with L2 > 1M: get_next_block is hotter than read_bunzip:
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| 25 | %time seconds calls function
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| 26 | 71.01 12.69 444 get_next_block
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| 27 | 28.65 5.12 93065 read_bunzip
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| 28 | 00.22 0.04 7736490 get_bits
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| 29 | 00.11 0.02 47 dealloc_bunzip
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| 30 | 00.00 0.00 93018 full_write
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| 31 | ...)
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| 32 |
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| 33 |
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| 34 | I would ask that anyone benefiting from this work, especially those
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| 35 | using it in commercial products, consider making a donation to my local
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| 36 | non-profit hospice organization (www.hospiceacadiana.com) in the name of
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| 37 | the woman I loved, Toni W. Hagan, who passed away Feb. 12, 2003.
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| 38 |
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| 39 | Manuel
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| 40 | */
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| 41 |
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| 42 | #include "libbb.h"
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[3232] | 43 | #include "bb_archive.h"
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[2725] | 44 |
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[3621] | 45 | #if 0
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| 46 | # define dbg(...) bb_error_msg(__VA_ARGS__)
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| 47 | #else
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| 48 | # define dbg(...) ((void)0)
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| 49 | #endif
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| 50 |
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[2725] | 51 | /* Constants for Huffman coding */
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| 52 | #define MAX_GROUPS 6
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| 53 | #define GROUP_SIZE 50 /* 64 would have been more efficient */
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| 54 | #define MAX_HUFCODE_BITS 20 /* Longest Huffman code allowed */
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| 55 | #define MAX_SYMBOLS 258 /* 256 literals + RUNA + RUNB */
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| 56 | #define SYMBOL_RUNA 0
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| 57 | #define SYMBOL_RUNB 1
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| 58 |
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| 59 | /* Status return values */
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| 60 | #define RETVAL_OK 0
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[3621] | 61 | #define RETVAL_LAST_BLOCK (dbg("%d", __LINE__), -1)
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| 62 | #define RETVAL_NOT_BZIP_DATA (dbg("%d", __LINE__), -2)
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| 63 | #define RETVAL_UNEXPECTED_INPUT_EOF (dbg("%d", __LINE__), -3)
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| 64 | #define RETVAL_SHORT_WRITE (dbg("%d", __LINE__), -4)
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| 65 | #define RETVAL_DATA_ERROR (dbg("%d", __LINE__), -5)
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| 66 | #define RETVAL_OUT_OF_MEMORY (dbg("%d", __LINE__), -6)
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| 67 | #define RETVAL_OBSOLETE_INPUT (dbg("%d", __LINE__), -7)
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[2725] | 68 |
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| 69 | /* Other housekeeping constants */
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| 70 | #define IOBUF_SIZE 4096
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| 71 |
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| 72 | /* This is what we know about each Huffman coding group */
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| 73 | struct group_data {
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| 74 | /* We have an extra slot at the end of limit[] for a sentinel value. */
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| 75 | int limit[MAX_HUFCODE_BITS+1], base[MAX_HUFCODE_BITS], permute[MAX_SYMBOLS];
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| 76 | int minLen, maxLen;
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| 77 | };
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| 78 |
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| 79 | /* Structure holding all the housekeeping data, including IO buffers and
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| 80 | * memory that persists between calls to bunzip
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| 81 | * Found the most used member:
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| 82 | * cat this_file.c | sed -e 's/"/ /g' -e "s/'/ /g" | xargs -n1 \
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| 83 | * | grep 'bd->' | sed 's/^.*bd->/bd->/' | sort | $PAGER
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| 84 | * and moved it (inbufBitCount) to offset 0.
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| 85 | */
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| 86 | struct bunzip_data {
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| 87 | /* I/O tracking data (file handles, buffers, positions, etc.) */
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| 88 | unsigned inbufBitCount, inbufBits;
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| 89 | int in_fd, out_fd, inbufCount, inbufPos /*, outbufPos*/;
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| 90 | uint8_t *inbuf /*,*outbuf*/;
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| 91 |
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| 92 | /* State for interrupting output loop */
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| 93 | int writeCopies, writePos, writeRunCountdown, writeCount;
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| 94 | int writeCurrent; /* actually a uint8_t */
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| 95 |
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| 96 | /* The CRC values stored in the block header and calculated from the data */
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| 97 | uint32_t headerCRC, totalCRC, writeCRC;
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| 98 |
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| 99 | /* Intermediate buffer and its size (in bytes) */
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| 100 | uint32_t *dbuf;
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| 101 | unsigned dbufSize;
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| 102 |
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| 103 | /* For I/O error handling */
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| 104 | jmp_buf jmpbuf;
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| 105 |
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| 106 | /* Big things go last (register-relative addressing can be larger for big offsets) */
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| 107 | uint32_t crc32Table[256];
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| 108 | uint8_t selectors[32768]; /* nSelectors=15 bits */
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| 109 | struct group_data groups[MAX_GROUPS]; /* Huffman coding tables */
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| 110 | };
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| 111 | /* typedef struct bunzip_data bunzip_data; -- done in .h file */
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| 112 |
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| 113 |
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| 114 | /* Return the next nnn bits of input. All reads from the compressed input
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| 115 | are done through this function. All reads are big endian */
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| 116 | static unsigned get_bits(bunzip_data *bd, int bits_wanted)
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| 117 | {
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| 118 | unsigned bits = 0;
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| 119 | /* Cache bd->inbufBitCount in a CPU register (hopefully): */
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| 120 | int bit_count = bd->inbufBitCount;
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| 121 |
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| 122 | /* If we need to get more data from the byte buffer, do so. (Loop getting
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| 123 | one byte at a time to enforce endianness and avoid unaligned access.) */
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| 124 | while (bit_count < bits_wanted) {
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| 125 |
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| 126 | /* If we need to read more data from file into byte buffer, do so */
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| 127 | if (bd->inbufPos == bd->inbufCount) {
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| 128 | /* if "no input fd" case: in_fd == -1, read fails, we jump */
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| 129 | bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE);
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| 130 | if (bd->inbufCount <= 0)
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| 131 | longjmp(bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF);
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| 132 | bd->inbufPos = 0;
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| 133 | }
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| 134 |
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| 135 | /* Avoid 32-bit overflow (dump bit buffer to top of output) */
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| 136 | if (bit_count >= 24) {
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| 137 | bits = bd->inbufBits & ((1 << bit_count) - 1);
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| 138 | bits_wanted -= bit_count;
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| 139 | bits <<= bits_wanted;
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| 140 | bit_count = 0;
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| 141 | }
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| 142 |
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| 143 | /* Grab next 8 bits of input from buffer. */
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| 144 | bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++];
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| 145 | bit_count += 8;
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| 146 | }
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| 147 |
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| 148 | /* Calculate result */
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| 149 | bit_count -= bits_wanted;
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| 150 | bd->inbufBitCount = bit_count;
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| 151 | bits |= (bd->inbufBits >> bit_count) & ((1 << bits_wanted) - 1);
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| 152 |
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| 153 | return bits;
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| 154 | }
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| 155 |
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| 156 | /* Unpacks the next block and sets up for the inverse Burrows-Wheeler step. */
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| 157 | static int get_next_block(bunzip_data *bd)
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| 158 | {
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| 159 | struct group_data *hufGroup;
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| 160 | int dbufCount, dbufSize, groupCount, *base, *limit, selector,
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| 161 | i, j, t, runPos, symCount, symTotal, nSelectors, byteCount[256];
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| 162 | int runCnt = runCnt; /* for compiler */
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| 163 | uint8_t uc, symToByte[256], mtfSymbol[256], *selectors;
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| 164 | uint32_t *dbuf;
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| 165 | unsigned origPtr;
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| 166 |
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| 167 | dbuf = bd->dbuf;
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| 168 | dbufSize = bd->dbufSize;
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| 169 | selectors = bd->selectors;
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| 170 |
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| 171 | /* In bbox, we are ok with aborting through setjmp which is set up in start_bunzip */
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| 172 | #if 0
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| 173 | /* Reset longjmp I/O error handling */
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| 174 | i = setjmp(bd->jmpbuf);
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| 175 | if (i) return i;
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| 176 | #endif
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| 177 |
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| 178 | /* Read in header signature and CRC, then validate signature.
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| 179 | (last block signature means CRC is for whole file, return now) */
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| 180 | i = get_bits(bd, 24);
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| 181 | j = get_bits(bd, 24);
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| 182 | bd->headerCRC = get_bits(bd, 32);
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| 183 | if ((i == 0x177245) && (j == 0x385090)) return RETVAL_LAST_BLOCK;
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| 184 | if ((i != 0x314159) || (j != 0x265359)) return RETVAL_NOT_BZIP_DATA;
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| 185 |
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| 186 | /* We can add support for blockRandomised if anybody complains. There was
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| 187 | some code for this in busybox 1.0.0-pre3, but nobody ever noticed that
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| 188 | it didn't actually work. */
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| 189 | if (get_bits(bd, 1)) return RETVAL_OBSOLETE_INPUT;
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| 190 | origPtr = get_bits(bd, 24);
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| 191 | if ((int)origPtr > dbufSize) return RETVAL_DATA_ERROR;
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| 192 |
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| 193 | /* mapping table: if some byte values are never used (encoding things
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| 194 | like ascii text), the compression code removes the gaps to have fewer
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| 195 | symbols to deal with, and writes a sparse bitfield indicating which
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| 196 | values were present. We make a translation table to convert the symbols
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| 197 | back to the corresponding bytes. */
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| 198 | symTotal = 0;
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| 199 | i = 0;
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| 200 | t = get_bits(bd, 16);
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| 201 | do {
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| 202 | if (t & (1 << 15)) {
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| 203 | unsigned inner_map = get_bits(bd, 16);
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| 204 | do {
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| 205 | if (inner_map & (1 << 15))
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| 206 | symToByte[symTotal++] = i;
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| 207 | inner_map <<= 1;
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| 208 | i++;
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| 209 | } while (i & 15);
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| 210 | i -= 16;
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| 211 | }
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| 212 | t <<= 1;
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| 213 | i += 16;
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| 214 | } while (i < 256);
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| 215 |
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| 216 | /* How many different Huffman coding groups does this block use? */
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| 217 | groupCount = get_bits(bd, 3);
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| 218 | if (groupCount < 2 || groupCount > MAX_GROUPS)
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| 219 | return RETVAL_DATA_ERROR;
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| 220 |
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| 221 | /* nSelectors: Every GROUP_SIZE many symbols we select a new Huffman coding
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| 222 | group. Read in the group selector list, which is stored as MTF encoded
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| 223 | bit runs. (MTF=Move To Front, as each value is used it's moved to the
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| 224 | start of the list.) */
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| 225 | for (i = 0; i < groupCount; i++)
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| 226 | mtfSymbol[i] = i;
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| 227 | nSelectors = get_bits(bd, 15);
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| 228 | if (!nSelectors)
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| 229 | return RETVAL_DATA_ERROR;
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| 230 | for (i = 0; i < nSelectors; i++) {
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| 231 | uint8_t tmp_byte;
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| 232 | /* Get next value */
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| 233 | int n = 0;
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| 234 | while (get_bits(bd, 1)) {
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| 235 | if (n >= groupCount) return RETVAL_DATA_ERROR;
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| 236 | n++;
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| 237 | }
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| 238 | /* Decode MTF to get the next selector */
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| 239 | tmp_byte = mtfSymbol[n];
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| 240 | while (--n >= 0)
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| 241 | mtfSymbol[n + 1] = mtfSymbol[n];
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| 242 | mtfSymbol[0] = selectors[i] = tmp_byte;
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| 243 | }
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| 244 |
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| 245 | /* Read the Huffman coding tables for each group, which code for symTotal
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| 246 | literal symbols, plus two run symbols (RUNA, RUNB) */
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| 247 | symCount = symTotal + 2;
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| 248 | for (j = 0; j < groupCount; j++) {
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| 249 | uint8_t length[MAX_SYMBOLS];
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| 250 | /* 8 bits is ALMOST enough for temp[], see below */
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| 251 | unsigned temp[MAX_HUFCODE_BITS+1];
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| 252 | int minLen, maxLen, pp, len_m1;
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| 253 |
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| 254 | /* Read Huffman code lengths for each symbol. They're stored in
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| 255 | a way similar to mtf; record a starting value for the first symbol,
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| 256 | and an offset from the previous value for every symbol after that.
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| 257 | (Subtracting 1 before the loop and then adding it back at the end is
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| 258 | an optimization that makes the test inside the loop simpler: symbol
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| 259 | length 0 becomes negative, so an unsigned inequality catches it.) */
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| 260 | len_m1 = get_bits(bd, 5) - 1;
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| 261 | for (i = 0; i < symCount; i++) {
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| 262 | for (;;) {
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| 263 | int two_bits;
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| 264 | if ((unsigned)len_m1 > (MAX_HUFCODE_BITS-1))
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| 265 | return RETVAL_DATA_ERROR;
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| 266 |
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| 267 | /* If first bit is 0, stop. Else second bit indicates whether
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| 268 | to increment or decrement the value. Optimization: grab 2
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| 269 | bits and unget the second if the first was 0. */
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| 270 | two_bits = get_bits(bd, 2);
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| 271 | if (two_bits < 2) {
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| 272 | bd->inbufBitCount++;
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| 273 | break;
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| 274 | }
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| 275 |
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| 276 | /* Add one if second bit 1, else subtract 1. Avoids if/else */
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| 277 | len_m1 += (((two_bits+1) & 2) - 1);
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| 278 | }
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| 279 |
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| 280 | /* Correct for the initial -1, to get the final symbol length */
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| 281 | length[i] = len_m1 + 1;
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| 282 | }
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| 283 |
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| 284 | /* Find largest and smallest lengths in this group */
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| 285 | minLen = maxLen = length[0];
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| 286 | for (i = 1; i < symCount; i++) {
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| 287 | if (length[i] > maxLen) maxLen = length[i];
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| 288 | else if (length[i] < minLen) minLen = length[i];
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| 289 | }
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| 290 |
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| 291 | /* Calculate permute[], base[], and limit[] tables from length[].
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| 292 | *
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| 293 | * permute[] is the lookup table for converting Huffman coded symbols
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| 294 | * into decoded symbols. base[] is the amount to subtract from the
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| 295 | * value of a Huffman symbol of a given length when using permute[].
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| 296 | *
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| 297 | * limit[] indicates the largest numerical value a symbol with a given
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| 298 | * number of bits can have. This is how the Huffman codes can vary in
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| 299 | * length: each code with a value>limit[length] needs another bit.
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| 300 | */
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| 301 | hufGroup = bd->groups + j;
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| 302 | hufGroup->minLen = minLen;
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| 303 | hufGroup->maxLen = maxLen;
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| 304 |
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| 305 | /* Note that minLen can't be smaller than 1, so we adjust the base
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| 306 | and limit array pointers so we're not always wasting the first
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| 307 | entry. We do this again when using them (during symbol decoding). */
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| 308 | base = hufGroup->base - 1;
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| 309 | limit = hufGroup->limit - 1;
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| 310 |
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| 311 | /* Calculate permute[]. Concurently, initialize temp[] and limit[]. */
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| 312 | pp = 0;
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| 313 | for (i = minLen; i <= maxLen; i++) {
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| 314 | int k;
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| 315 | temp[i] = limit[i] = 0;
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| 316 | for (k = 0; k < symCount; k++)
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| 317 | if (length[k] == i)
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| 318 | hufGroup->permute[pp++] = k;
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| 319 | }
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| 320 |
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| 321 | /* Count symbols coded for at each bit length */
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| 322 | /* NB: in pathological cases, temp[8] can end ip being 256.
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| 323 | * That's why uint8_t is too small for temp[]. */
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| 324 | for (i = 0; i < symCount; i++) temp[length[i]]++;
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| 325 |
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| 326 | /* Calculate limit[] (the largest symbol-coding value at each bit
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| 327 | * length, which is (previous limit<<1)+symbols at this level), and
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| 328 | * base[] (number of symbols to ignore at each bit length, which is
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| 329 | * limit minus the cumulative count of symbols coded for already). */
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| 330 | pp = t = 0;
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| 331 | for (i = minLen; i < maxLen;) {
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| 332 | unsigned temp_i = temp[i];
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| 333 |
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| 334 | pp += temp_i;
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| 335 |
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| 336 | /* We read the largest possible symbol size and then unget bits
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| 337 | after determining how many we need, and those extra bits could
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| 338 | be set to anything. (They're noise from future symbols.) At
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| 339 | each level we're really only interested in the first few bits,
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| 340 | so here we set all the trailing to-be-ignored bits to 1 so they
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| 341 | don't affect the value>limit[length] comparison. */
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| 342 | limit[i] = (pp << (maxLen - i)) - 1;
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| 343 | pp <<= 1;
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| 344 | t += temp_i;
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| 345 | base[++i] = pp - t;
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| 346 | }
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| 347 | limit[maxLen] = pp + temp[maxLen] - 1;
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| 348 | limit[maxLen+1] = INT_MAX; /* Sentinel value for reading next sym. */
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| 349 | base[minLen] = 0;
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| 350 | }
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| 351 |
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| 352 | /* We've finished reading and digesting the block header. Now read this
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| 353 | block's Huffman coded symbols from the file and undo the Huffman coding
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| 354 | and run length encoding, saving the result into dbuf[dbufCount++] = uc */
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| 355 |
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| 356 | /* Initialize symbol occurrence counters and symbol Move To Front table */
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| 357 | /*memset(byteCount, 0, sizeof(byteCount)); - smaller, but slower */
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| 358 | for (i = 0; i < 256; i++) {
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| 359 | byteCount[i] = 0;
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| 360 | mtfSymbol[i] = (uint8_t)i;
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| 361 | }
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| 362 |
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| 363 | /* Loop through compressed symbols. */
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| 364 |
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| 365 | runPos = dbufCount = selector = 0;
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| 366 | for (;;) {
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| 367 | int nextSym;
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| 368 |
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| 369 | /* Fetch next Huffman coding group from list. */
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| 370 | symCount = GROUP_SIZE - 1;
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| 371 | if (selector >= nSelectors) return RETVAL_DATA_ERROR;
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| 372 | hufGroup = bd->groups + selectors[selector++];
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| 373 | base = hufGroup->base - 1;
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| 374 | limit = hufGroup->limit - 1;
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| 375 |
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| 376 | continue_this_group:
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| 377 | /* Read next Huffman-coded symbol. */
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| 378 |
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| 379 | /* Note: It is far cheaper to read maxLen bits and back up than it is
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| 380 | to read minLen bits and then add additional bit at a time, testing
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| 381 | as we go. Because there is a trailing last block (with file CRC),
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| 382 | there is no danger of the overread causing an unexpected EOF for a
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| 383 | valid compressed file.
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| 384 | */
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| 385 | if (1) {
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| 386 | /* As a further optimization, we do the read inline
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| 387 | (falling back to a call to get_bits if the buffer runs dry).
|
---|
| 388 | */
|
---|
| 389 | int new_cnt;
|
---|
| 390 | while ((new_cnt = bd->inbufBitCount - hufGroup->maxLen) < 0) {
|
---|
| 391 | /* bd->inbufBitCount < hufGroup->maxLen */
|
---|
| 392 | if (bd->inbufPos == bd->inbufCount) {
|
---|
| 393 | nextSym = get_bits(bd, hufGroup->maxLen);
|
---|
| 394 | goto got_huff_bits;
|
---|
| 395 | }
|
---|
| 396 | bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++];
|
---|
| 397 | bd->inbufBitCount += 8;
|
---|
| 398 | };
|
---|
| 399 | bd->inbufBitCount = new_cnt; /* "bd->inbufBitCount -= hufGroup->maxLen;" */
|
---|
| 400 | nextSym = (bd->inbufBits >> new_cnt) & ((1 << hufGroup->maxLen) - 1);
|
---|
| 401 | got_huff_bits: ;
|
---|
| 402 | } else { /* unoptimized equivalent */
|
---|
| 403 | nextSym = get_bits(bd, hufGroup->maxLen);
|
---|
| 404 | }
|
---|
| 405 | /* Figure how many bits are in next symbol and unget extras */
|
---|
| 406 | i = hufGroup->minLen;
|
---|
| 407 | while (nextSym > limit[i]) ++i;
|
---|
| 408 | j = hufGroup->maxLen - i;
|
---|
| 409 | if (j < 0)
|
---|
| 410 | return RETVAL_DATA_ERROR;
|
---|
| 411 | bd->inbufBitCount += j;
|
---|
| 412 |
|
---|
| 413 | /* Huffman decode value to get nextSym (with bounds checking) */
|
---|
| 414 | nextSym = (nextSym >> j) - base[i];
|
---|
| 415 | if ((unsigned)nextSym >= MAX_SYMBOLS)
|
---|
| 416 | return RETVAL_DATA_ERROR;
|
---|
| 417 | nextSym = hufGroup->permute[nextSym];
|
---|
| 418 |
|
---|
| 419 | /* We have now decoded the symbol, which indicates either a new literal
|
---|
| 420 | byte, or a repeated run of the most recent literal byte. First,
|
---|
| 421 | check if nextSym indicates a repeated run, and if so loop collecting
|
---|
| 422 | how many times to repeat the last literal. */
|
---|
| 423 | if ((unsigned)nextSym <= SYMBOL_RUNB) { /* RUNA or RUNB */
|
---|
| 424 |
|
---|
| 425 | /* If this is the start of a new run, zero out counter */
|
---|
| 426 | if (runPos == 0) {
|
---|
| 427 | runPos = 1;
|
---|
| 428 | runCnt = 0;
|
---|
| 429 | }
|
---|
| 430 |
|
---|
| 431 | /* Neat trick that saves 1 symbol: instead of or-ing 0 or 1 at
|
---|
| 432 | each bit position, add 1 or 2 instead. For example,
|
---|
| 433 | 1011 is 1<<0 + 1<<1 + 2<<2. 1010 is 2<<0 + 2<<1 + 1<<2.
|
---|
| 434 | You can make any bit pattern that way using 1 less symbol than
|
---|
| 435 | the basic or 0/1 method (except all bits 0, which would use no
|
---|
| 436 | symbols, but a run of length 0 doesn't mean anything in this
|
---|
| 437 | context). Thus space is saved. */
|
---|
| 438 | runCnt += (runPos << nextSym); /* +runPos if RUNA; +2*runPos if RUNB */
|
---|
| 439 | if (runPos < dbufSize) runPos <<= 1;
|
---|
| 440 | goto end_of_huffman_loop;
|
---|
| 441 | }
|
---|
| 442 |
|
---|
| 443 | /* When we hit the first non-run symbol after a run, we now know
|
---|
| 444 | how many times to repeat the last literal, so append that many
|
---|
| 445 | copies to our buffer of decoded symbols (dbuf) now. (The last
|
---|
| 446 | literal used is the one at the head of the mtfSymbol array.) */
|
---|
| 447 | if (runPos != 0) {
|
---|
| 448 | uint8_t tmp_byte;
|
---|
[3621] | 449 | if (dbufCount + runCnt > dbufSize) {
|
---|
| 450 | dbg("dbufCount:%d+runCnt:%d %d > dbufSize:%d RETVAL_DATA_ERROR",
|
---|
| 451 | dbufCount, runCnt, dbufCount + runCnt, dbufSize);
|
---|
| 452 | return RETVAL_DATA_ERROR;
|
---|
| 453 | }
|
---|
[2725] | 454 | tmp_byte = symToByte[mtfSymbol[0]];
|
---|
| 455 | byteCount[tmp_byte] += runCnt;
|
---|
| 456 | while (--runCnt >= 0) dbuf[dbufCount++] = (uint32_t)tmp_byte;
|
---|
| 457 | runPos = 0;
|
---|
| 458 | }
|
---|
| 459 |
|
---|
| 460 | /* Is this the terminating symbol? */
|
---|
| 461 | if (nextSym > symTotal) break;
|
---|
| 462 |
|
---|
| 463 | /* At this point, nextSym indicates a new literal character. Subtract
|
---|
| 464 | one to get the position in the MTF array at which this literal is
|
---|
| 465 | currently to be found. (Note that the result can't be -1 or 0,
|
---|
| 466 | because 0 and 1 are RUNA and RUNB. But another instance of the
|
---|
| 467 | first symbol in the mtf array, position 0, would have been handled
|
---|
| 468 | as part of a run above. Therefore 1 unused mtf position minus
|
---|
| 469 | 2 non-literal nextSym values equals -1.) */
|
---|
| 470 | if (dbufCount >= dbufSize) return RETVAL_DATA_ERROR;
|
---|
| 471 | i = nextSym - 1;
|
---|
| 472 | uc = mtfSymbol[i];
|
---|
| 473 |
|
---|
| 474 | /* Adjust the MTF array. Since we typically expect to move only a
|
---|
| 475 | * small number of symbols, and are bound by 256 in any case, using
|
---|
| 476 | * memmove here would typically be bigger and slower due to function
|
---|
| 477 | * call overhead and other assorted setup costs. */
|
---|
| 478 | do {
|
---|
| 479 | mtfSymbol[i] = mtfSymbol[i-1];
|
---|
| 480 | } while (--i);
|
---|
| 481 | mtfSymbol[0] = uc;
|
---|
| 482 | uc = symToByte[uc];
|
---|
| 483 |
|
---|
| 484 | /* We have our literal byte. Save it into dbuf. */
|
---|
| 485 | byteCount[uc]++;
|
---|
| 486 | dbuf[dbufCount++] = (uint32_t)uc;
|
---|
| 487 |
|
---|
| 488 | /* Skip group initialization if we're not done with this group. Done
|
---|
| 489 | * this way to avoid compiler warning. */
|
---|
| 490 | end_of_huffman_loop:
|
---|
| 491 | if (--symCount >= 0) goto continue_this_group;
|
---|
| 492 | }
|
---|
| 493 |
|
---|
| 494 | /* At this point, we've read all the Huffman-coded symbols (and repeated
|
---|
| 495 | runs) for this block from the input stream, and decoded them into the
|
---|
| 496 | intermediate buffer. There are dbufCount many decoded bytes in dbuf[].
|
---|
| 497 | Now undo the Burrows-Wheeler transform on dbuf.
|
---|
| 498 | See http://dogma.net/markn/articles/bwt/bwt.htm
|
---|
| 499 | */
|
---|
| 500 |
|
---|
| 501 | /* Turn byteCount into cumulative occurrence counts of 0 to n-1. */
|
---|
| 502 | j = 0;
|
---|
| 503 | for (i = 0; i < 256; i++) {
|
---|
| 504 | int tmp_count = j + byteCount[i];
|
---|
| 505 | byteCount[i] = j;
|
---|
| 506 | j = tmp_count;
|
---|
| 507 | }
|
---|
| 508 |
|
---|
| 509 | /* Figure out what order dbuf would be in if we sorted it. */
|
---|
| 510 | for (i = 0; i < dbufCount; i++) {
|
---|
| 511 | uint8_t tmp_byte = (uint8_t)dbuf[i];
|
---|
| 512 | int tmp_count = byteCount[tmp_byte];
|
---|
| 513 | dbuf[tmp_count] |= (i << 8);
|
---|
| 514 | byteCount[tmp_byte] = tmp_count + 1;
|
---|
| 515 | }
|
---|
| 516 |
|
---|
| 517 | /* Decode first byte by hand to initialize "previous" byte. Note that it
|
---|
| 518 | doesn't get output, and if the first three characters are identical
|
---|
| 519 | it doesn't qualify as a run (hence writeRunCountdown=5). */
|
---|
| 520 | if (dbufCount) {
|
---|
| 521 | uint32_t tmp;
|
---|
| 522 | if ((int)origPtr >= dbufCount) return RETVAL_DATA_ERROR;
|
---|
| 523 | tmp = dbuf[origPtr];
|
---|
| 524 | bd->writeCurrent = (uint8_t)tmp;
|
---|
| 525 | bd->writePos = (tmp >> 8);
|
---|
| 526 | bd->writeRunCountdown = 5;
|
---|
| 527 | }
|
---|
| 528 | bd->writeCount = dbufCount;
|
---|
| 529 |
|
---|
| 530 | return RETVAL_OK;
|
---|
| 531 | }
|
---|
| 532 |
|
---|
| 533 | /* Undo Burrows-Wheeler transform on intermediate buffer to produce output.
|
---|
| 534 | If start_bunzip was initialized with out_fd=-1, then up to len bytes of
|
---|
| 535 | data are written to outbuf. Return value is number of bytes written or
|
---|
| 536 | error (all errors are negative numbers). If out_fd!=-1, outbuf and len
|
---|
| 537 | are ignored, data is written to out_fd and return is RETVAL_OK or error.
|
---|
| 538 |
|
---|
| 539 | NB: read_bunzip returns < 0 on error, or the number of *unfilled* bytes
|
---|
| 540 | in outbuf. IOW: on EOF returns len ("all bytes are not filled"), not 0.
|
---|
| 541 | (Why? This allows to get rid of one local variable)
|
---|
| 542 | */
|
---|
| 543 | int FAST_FUNC read_bunzip(bunzip_data *bd, char *outbuf, int len)
|
---|
| 544 | {
|
---|
| 545 | const uint32_t *dbuf;
|
---|
| 546 | int pos, current, previous;
|
---|
| 547 | uint32_t CRC;
|
---|
| 548 |
|
---|
| 549 | /* If we already have error/end indicator, return it */
|
---|
| 550 | if (bd->writeCount < 0)
|
---|
| 551 | return bd->writeCount;
|
---|
| 552 |
|
---|
| 553 | dbuf = bd->dbuf;
|
---|
| 554 |
|
---|
| 555 | /* Register-cached state (hopefully): */
|
---|
| 556 | pos = bd->writePos;
|
---|
| 557 | current = bd->writeCurrent;
|
---|
| 558 | CRC = bd->writeCRC; /* small loss on x86-32 (not enough regs), win on x86-64 */
|
---|
| 559 |
|
---|
| 560 | /* We will always have pending decoded data to write into the output
|
---|
| 561 | buffer unless this is the very first call (in which case we haven't
|
---|
| 562 | Huffman-decoded a block into the intermediate buffer yet). */
|
---|
| 563 | if (bd->writeCopies) {
|
---|
| 564 |
|
---|
| 565 | dec_writeCopies:
|
---|
| 566 | /* Inside the loop, writeCopies means extra copies (beyond 1) */
|
---|
| 567 | --bd->writeCopies;
|
---|
| 568 |
|
---|
| 569 | /* Loop outputting bytes */
|
---|
| 570 | for (;;) {
|
---|
| 571 |
|
---|
| 572 | /* If the output buffer is full, save cached state and return */
|
---|
| 573 | if (--len < 0) {
|
---|
| 574 | /* Unlikely branch.
|
---|
| 575 | * Use of "goto" instead of keeping code here
|
---|
| 576 | * helps compiler to realize this. */
|
---|
| 577 | goto outbuf_full;
|
---|
| 578 | }
|
---|
| 579 |
|
---|
| 580 | /* Write next byte into output buffer, updating CRC */
|
---|
| 581 | *outbuf++ = current;
|
---|
| 582 | CRC = (CRC << 8) ^ bd->crc32Table[(CRC >> 24) ^ current];
|
---|
| 583 |
|
---|
| 584 | /* Loop now if we're outputting multiple copies of this byte */
|
---|
| 585 | if (bd->writeCopies) {
|
---|
| 586 | /* Unlikely branch */
|
---|
| 587 | /*--bd->writeCopies;*/
|
---|
| 588 | /*continue;*/
|
---|
| 589 | /* Same, but (ab)using other existing --writeCopies operation
|
---|
| 590 | * (and this if() compiles into just test+branch pair): */
|
---|
| 591 | goto dec_writeCopies;
|
---|
| 592 | }
|
---|
| 593 | decode_next_byte:
|
---|
| 594 | if (--bd->writeCount < 0)
|
---|
| 595 | break; /* input block is fully consumed, need next one */
|
---|
| 596 |
|
---|
| 597 | /* Follow sequence vector to undo Burrows-Wheeler transform */
|
---|
| 598 | previous = current;
|
---|
| 599 | pos = dbuf[pos];
|
---|
| 600 | current = (uint8_t)pos;
|
---|
| 601 | pos >>= 8;
|
---|
| 602 |
|
---|
| 603 | /* After 3 consecutive copies of the same byte, the 4th
|
---|
| 604 | * is a repeat count. We count down from 4 instead
|
---|
| 605 | * of counting up because testing for non-zero is faster */
|
---|
| 606 | if (--bd->writeRunCountdown != 0) {
|
---|
| 607 | if (current != previous)
|
---|
| 608 | bd->writeRunCountdown = 4;
|
---|
| 609 | } else {
|
---|
| 610 | /* Unlikely branch */
|
---|
| 611 | /* We have a repeated run, this byte indicates the count */
|
---|
| 612 | bd->writeCopies = current;
|
---|
| 613 | current = previous;
|
---|
| 614 | bd->writeRunCountdown = 5;
|
---|
| 615 |
|
---|
| 616 | /* Sometimes there are just 3 bytes (run length 0) */
|
---|
| 617 | if (!bd->writeCopies) goto decode_next_byte;
|
---|
| 618 |
|
---|
| 619 | /* Subtract the 1 copy we'd output anyway to get extras */
|
---|
| 620 | --bd->writeCopies;
|
---|
| 621 | }
|
---|
| 622 | } /* for(;;) */
|
---|
| 623 |
|
---|
| 624 | /* Decompression of this input block completed successfully */
|
---|
| 625 | bd->writeCRC = CRC = ~CRC;
|
---|
| 626 | bd->totalCRC = ((bd->totalCRC << 1) | (bd->totalCRC >> 31)) ^ CRC;
|
---|
| 627 |
|
---|
| 628 | /* If this block had a CRC error, force file level CRC error */
|
---|
| 629 | if (CRC != bd->headerCRC) {
|
---|
| 630 | bd->totalCRC = bd->headerCRC + 1;
|
---|
| 631 | return RETVAL_LAST_BLOCK;
|
---|
| 632 | }
|
---|
| 633 | }
|
---|
| 634 |
|
---|
| 635 | /* Refill the intermediate buffer by Huffman-decoding next block of input */
|
---|
| 636 | {
|
---|
| 637 | int r = get_next_block(bd);
|
---|
| 638 | if (r) { /* error/end */
|
---|
| 639 | bd->writeCount = r;
|
---|
| 640 | return (r != RETVAL_LAST_BLOCK) ? r : len;
|
---|
| 641 | }
|
---|
| 642 | }
|
---|
| 643 |
|
---|
| 644 | CRC = ~0;
|
---|
| 645 | pos = bd->writePos;
|
---|
| 646 | current = bd->writeCurrent;
|
---|
| 647 | goto decode_next_byte;
|
---|
| 648 |
|
---|
| 649 | outbuf_full:
|
---|
| 650 | /* Output buffer is full, save cached state and return */
|
---|
| 651 | bd->writePos = pos;
|
---|
| 652 | bd->writeCurrent = current;
|
---|
| 653 | bd->writeCRC = CRC;
|
---|
| 654 |
|
---|
| 655 | bd->writeCopies++;
|
---|
| 656 |
|
---|
| 657 | return 0;
|
---|
| 658 | }
|
---|
| 659 |
|
---|
| 660 | /* Allocate the structure, read file header. If in_fd==-1, inbuf must contain
|
---|
| 661 | a complete bunzip file (len bytes long). If in_fd!=-1, inbuf and len are
|
---|
| 662 | ignored, and data is read from file handle into temporary buffer. */
|
---|
| 663 |
|
---|
| 664 | /* Because bunzip2 is used for help text unpacking, and because bb_show_usage()
|
---|
| 665 | should work for NOFORK applets too, we must be extremely careful to not leak
|
---|
| 666 | any allocations! */
|
---|
| 667 | int FAST_FUNC start_bunzip(bunzip_data **bdp, int in_fd,
|
---|
| 668 | const void *inbuf, int len)
|
---|
| 669 | {
|
---|
| 670 | bunzip_data *bd;
|
---|
| 671 | unsigned i;
|
---|
| 672 | enum {
|
---|
| 673 | BZh0 = ('B' << 24) + ('Z' << 16) + ('h' << 8) + '0',
|
---|
| 674 | h0 = ('h' << 8) + '0',
|
---|
| 675 | };
|
---|
| 676 |
|
---|
| 677 | /* Figure out how much data to allocate */
|
---|
| 678 | i = sizeof(bunzip_data);
|
---|
| 679 | if (in_fd != -1) i += IOBUF_SIZE;
|
---|
| 680 |
|
---|
| 681 | /* Allocate bunzip_data. Most fields initialize to zero. */
|
---|
| 682 | bd = *bdp = xzalloc(i);
|
---|
| 683 |
|
---|
| 684 | /* Setup input buffer */
|
---|
| 685 | bd->in_fd = in_fd;
|
---|
| 686 | if (-1 == in_fd) {
|
---|
| 687 | /* in this case, bd->inbuf is read-only */
|
---|
| 688 | bd->inbuf = (void*)inbuf; /* cast away const-ness */
|
---|
| 689 | } else {
|
---|
| 690 | bd->inbuf = (uint8_t*)(bd + 1);
|
---|
| 691 | memcpy(bd->inbuf, inbuf, len);
|
---|
| 692 | }
|
---|
| 693 | bd->inbufCount = len;
|
---|
| 694 |
|
---|
| 695 | /* Init the CRC32 table (big endian) */
|
---|
| 696 | crc32_filltable(bd->crc32Table, 1);
|
---|
| 697 |
|
---|
| 698 | /* Setup for I/O error handling via longjmp */
|
---|
| 699 | i = setjmp(bd->jmpbuf);
|
---|
| 700 | if (i) return i;
|
---|
| 701 |
|
---|
| 702 | /* Ensure that file starts with "BZh['1'-'9']." */
|
---|
| 703 | /* Update: now caller verifies 1st two bytes, makes .gz/.bz2
|
---|
| 704 | * integration easier */
|
---|
| 705 | /* was: */
|
---|
| 706 | /* i = get_bits(bd, 32); */
|
---|
| 707 | /* if ((unsigned)(i - BZh0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA; */
|
---|
| 708 | i = get_bits(bd, 16);
|
---|
| 709 | if ((unsigned)(i - h0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA;
|
---|
| 710 |
|
---|
| 711 | /* Fourth byte (ascii '1'-'9') indicates block size in units of 100k of
|
---|
| 712 | uncompressed data. Allocate intermediate buffer for block. */
|
---|
| 713 | /* bd->dbufSize = 100000 * (i - BZh0); */
|
---|
| 714 | bd->dbufSize = 100000 * (i - h0);
|
---|
| 715 |
|
---|
| 716 | /* Cannot use xmalloc - may leak bd in NOFORK case! */
|
---|
| 717 | bd->dbuf = malloc_or_warn(bd->dbufSize * sizeof(bd->dbuf[0]));
|
---|
| 718 | if (!bd->dbuf) {
|
---|
| 719 | free(bd);
|
---|
| 720 | xfunc_die();
|
---|
| 721 | }
|
---|
| 722 | return RETVAL_OK;
|
---|
| 723 | }
|
---|
| 724 |
|
---|
| 725 | void FAST_FUNC dealloc_bunzip(bunzip_data *bd)
|
---|
| 726 | {
|
---|
| 727 | free(bd->dbuf);
|
---|
| 728 | free(bd);
|
---|
| 729 | }
|
---|
| 730 |
|
---|
| 731 |
|
---|
| 732 | /* Decompress src_fd to dst_fd. Stops at end of bzip data, not end of file. */
|
---|
| 733 | IF_DESKTOP(long long) int FAST_FUNC
|
---|
[3621] | 734 | unpack_bz2_stream(transformer_state_t *xstate)
|
---|
[2725] | 735 | {
|
---|
| 736 | IF_DESKTOP(long long total_written = 0;)
|
---|
| 737 | bunzip_data *bd;
|
---|
| 738 | char *outbuf;
|
---|
| 739 | int i;
|
---|
| 740 | unsigned len;
|
---|
| 741 |
|
---|
[3621] | 742 | if (check_signature16(xstate, BZIP2_MAGIC))
|
---|
[3232] | 743 | return -1;
|
---|
| 744 |
|
---|
[2725] | 745 | outbuf = xmalloc(IOBUF_SIZE);
|
---|
| 746 | len = 0;
|
---|
| 747 | while (1) { /* "Process one BZ... stream" loop */
|
---|
| 748 |
|
---|
[3621] | 749 | i = start_bunzip(&bd, xstate->src_fd, outbuf + 2, len);
|
---|
[2725] | 750 |
|
---|
| 751 | if (i == 0) {
|
---|
| 752 | while (1) { /* "Produce some output bytes" loop */
|
---|
| 753 | i = read_bunzip(bd, outbuf, IOBUF_SIZE);
|
---|
| 754 | if (i < 0) /* error? */
|
---|
| 755 | break;
|
---|
| 756 | i = IOBUF_SIZE - i; /* number of bytes produced */
|
---|
| 757 | if (i == 0) /* EOF? */
|
---|
| 758 | break;
|
---|
[3621] | 759 | if (i != transformer_write(xstate, outbuf, i)) {
|
---|
[2725] | 760 | i = RETVAL_SHORT_WRITE;
|
---|
| 761 | goto release_mem;
|
---|
| 762 | }
|
---|
| 763 | IF_DESKTOP(total_written += i;)
|
---|
| 764 | }
|
---|
| 765 | }
|
---|
| 766 |
|
---|
[3232] | 767 | if (i != RETVAL_LAST_BLOCK
|
---|
| 768 | /* Observed case when i == RETVAL_OK:
|
---|
| 769 | * "bzcat z.bz2", where "z.bz2" is a bzipped zero-length file
|
---|
| 770 | * (to be exact, z.bz2 is exactly these 14 bytes:
|
---|
| 771 | * 42 5a 68 39 17 72 45 38 50 90 00 00 00 00).
|
---|
| 772 | */
|
---|
| 773 | && i != RETVAL_OK
|
---|
| 774 | ) {
|
---|
[2725] | 775 | bb_error_msg("bunzip error %d", i);
|
---|
| 776 | break;
|
---|
| 777 | }
|
---|
| 778 | if (bd->headerCRC != bd->totalCRC) {
|
---|
| 779 | bb_error_msg("CRC error");
|
---|
| 780 | break;
|
---|
| 781 | }
|
---|
| 782 |
|
---|
| 783 | /* Successfully unpacked one BZ stream */
|
---|
| 784 | i = RETVAL_OK;
|
---|
| 785 |
|
---|
| 786 | /* Do we have "BZ..." after last processed byte?
|
---|
| 787 | * pbzip2 (parallelized bzip2) produces such files.
|
---|
| 788 | */
|
---|
| 789 | len = bd->inbufCount - bd->inbufPos;
|
---|
| 790 | memcpy(outbuf, &bd->inbuf[bd->inbufPos], len);
|
---|
| 791 | if (len < 2) {
|
---|
[3621] | 792 | if (safe_read(xstate->src_fd, outbuf + len, 2 - len) != 2 - len)
|
---|
[2725] | 793 | break;
|
---|
| 794 | len = 2;
|
---|
| 795 | }
|
---|
| 796 | if (*(uint16_t*)outbuf != BZIP2_MAGIC) /* "BZ"? */
|
---|
| 797 | break;
|
---|
| 798 | dealloc_bunzip(bd);
|
---|
| 799 | len -= 2;
|
---|
| 800 | }
|
---|
| 801 |
|
---|
| 802 | release_mem:
|
---|
| 803 | dealloc_bunzip(bd);
|
---|
| 804 | free(outbuf);
|
---|
| 805 |
|
---|
| 806 | return i ? i : IF_DESKTOP(total_written) + 0;
|
---|
| 807 | }
|
---|
| 808 |
|
---|
| 809 | #ifdef TESTING
|
---|
| 810 |
|
---|
| 811 | static char *const bunzip_errors[] = {
|
---|
| 812 | NULL, "Bad file checksum", "Not bzip data",
|
---|
| 813 | "Unexpected input EOF", "Unexpected output EOF", "Data error",
|
---|
| 814 | "Out of memory", "Obsolete (pre 0.9.5) bzip format not supported"
|
---|
| 815 | };
|
---|
| 816 |
|
---|
| 817 | /* Dumb little test thing, decompress stdin to stdout */
|
---|
| 818 | int main(int argc, char **argv)
|
---|
| 819 | {
|
---|
| 820 | char c;
|
---|
| 821 |
|
---|
[3232] | 822 | int i = unpack_bz2_stream(0, 1);
|
---|
[2725] | 823 | if (i < 0)
|
---|
| 824 | fprintf(stderr, "%s\n", bunzip_errors[-i]);
|
---|
| 825 | else if (read(STDIN_FILENO, &c, 1))
|
---|
| 826 | fprintf(stderr, "Trailing garbage ignored\n");
|
---|
| 827 | return -i;
|
---|
| 828 | }
|
---|
| 829 | #endif
|
---|