[821] | 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 tarball for details.
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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_unzip() 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 | I would ask that anyone benefiting from this work, especially those
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| 24 | using it in commercial products, consider making a donation to my local
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| 25 | non-profit hospice organization (www.hospiceacadiana.com) in the name of
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| 26 | the woman I loved, Toni W. Hagan, who passed away Feb. 12, 2003.
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| 27 |
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| 28 | Manuel
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| 29 | */
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| 30 |
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| 31 | #include "libbb.h"
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| 32 | #include "unarchive.h"
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| 33 |
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| 34 | /* Constants for Huffman coding */
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[1770] | 35 | #define MAX_GROUPS 6
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| 36 | #define GROUP_SIZE 50 /* 64 would have been more efficient */
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| 37 | #define MAX_HUFCODE_BITS 20 /* Longest Huffman code allowed */
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| 38 | #define MAX_SYMBOLS 258 /* 256 literals + RUNA + RUNB */
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| 39 | #define SYMBOL_RUNA 0
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| 40 | #define SYMBOL_RUNB 1
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[821] | 41 |
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| 42 | /* Status return values */
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[1770] | 43 | #define RETVAL_OK 0
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| 44 | #define RETVAL_LAST_BLOCK (-1)
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| 45 | #define RETVAL_NOT_BZIP_DATA (-2)
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| 46 | #define RETVAL_UNEXPECTED_INPUT_EOF (-3)
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| 47 | #define RETVAL_UNEXPECTED_OUTPUT_EOF (-4)
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| 48 | #define RETVAL_DATA_ERROR (-5)
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| 49 | #define RETVAL_OUT_OF_MEMORY (-6)
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| 50 | #define RETVAL_OBSOLETE_INPUT (-7)
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[821] | 51 |
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| 52 | /* Other housekeeping constants */
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[1770] | 53 | #define IOBUF_SIZE 4096
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[821] | 54 |
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| 55 | /* This is what we know about each Huffman coding group */
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| 56 | struct group_data {
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| 57 | /* We have an extra slot at the end of limit[] for a sentinal value. */
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[1770] | 58 | int limit[MAX_HUFCODE_BITS+1], base[MAX_HUFCODE_BITS], permute[MAX_SYMBOLS];
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[821] | 59 | int minLen, maxLen;
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| 60 | };
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| 61 |
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| 62 | /* Structure holding all the housekeeping data, including IO buffers and
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| 63 | memory that persists between calls to bunzip */
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| 64 |
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[1770] | 65 | struct bunzip_data {
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[821] | 66 | /* State for interrupting output loop */
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[1770] | 67 | int writeCopies, writePos, writeRunCountdown, writeCount, writeCurrent;
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[821] | 68 |
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| 69 | /* I/O tracking data (file handles, buffers, positions, etc.) */
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[1770] | 70 | int in_fd, out_fd, inbufCount, inbufPos /*, outbufPos*/;
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[821] | 71 | unsigned char *inbuf /*,*outbuf*/;
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[1770] | 72 | unsigned inbufBitCount, inbufBits;
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[821] | 73 |
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| 74 | /* The CRC values stored in the block header and calculated from the data */
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[1770] | 75 | uint32_t headerCRC, totalCRC, writeCRC;
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[821] | 76 |
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| 77 | /* Intermediate buffer and its size (in bytes) */
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[1770] | 78 | unsigned *dbuf, dbufSize;
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[821] | 79 |
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[1770] | 80 | /* For I/O error handling */
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| 81 | jmp_buf jmpbuf;
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[821] | 82 |
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[1770] | 83 | /* Big things go last (register-relative addressing can be larger for big offsets */
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| 84 | uint32_t crc32Table[256];
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[821] | 85 | unsigned char selectors[32768]; /* nSelectors=15 bits */
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| 86 | struct group_data groups[MAX_GROUPS]; /* Huffman coding tables */
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[1770] | 87 | };
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| 88 | /* typedef struct bunzip_data bunzip_data; -- done in .h file */
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[821] | 89 |
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| 90 |
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| 91 | /* Return the next nnn bits of input. All reads from the compressed input
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| 92 | are done through this function. All reads are big endian */
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| 93 |
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[1770] | 94 | static unsigned get_bits(bunzip_data *bd, char bits_wanted)
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[821] | 95 | {
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[1770] | 96 | unsigned bits = 0;
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[821] | 97 |
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| 98 | /* If we need to get more data from the byte buffer, do so. (Loop getting
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| 99 | one byte at a time to enforce endianness and avoid unaligned access.) */
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| 100 |
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[1770] | 101 | while (bd->inbufBitCount < bits_wanted) {
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[821] | 102 |
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| 103 | /* If we need to read more data from file into byte buffer, do so */
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| 104 |
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[1770] | 105 | if (bd->inbufPos == bd->inbufCount) {
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| 106 | /* if "no input fd" case: in_fd == -1, read fails, we jump */
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| 107 | bd->inbufCount = read(bd->in_fd, bd->inbuf, IOBUF_SIZE);
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| 108 | if (bd->inbufCount <= 0)
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| 109 | longjmp(bd->jmpbuf, RETVAL_UNEXPECTED_INPUT_EOF);
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| 110 | bd->inbufPos = 0;
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[821] | 111 | }
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| 112 |
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| 113 | /* Avoid 32-bit overflow (dump bit buffer to top of output) */
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| 114 |
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[1770] | 115 | if (bd->inbufBitCount >= 24) {
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| 116 | bits = bd->inbufBits & ((1 << bd->inbufBitCount) - 1);
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| 117 | bits_wanted -= bd->inbufBitCount;
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| 118 | bits <<= bits_wanted;
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| 119 | bd->inbufBitCount = 0;
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[821] | 120 | }
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| 121 |
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| 122 | /* Grab next 8 bits of input from buffer. */
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| 123 |
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[1770] | 124 | bd->inbufBits = (bd->inbufBits<<8) | bd->inbuf[bd->inbufPos++];
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| 125 | bd->inbufBitCount += 8;
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[821] | 126 | }
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| 127 |
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| 128 | /* Calculate result */
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| 129 |
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[1770] | 130 | bd->inbufBitCount -= bits_wanted;
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| 131 | bits |= (bd->inbufBits >> bd->inbufBitCount) & ((1 << bits_wanted) - 1);
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[821] | 132 |
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| 133 | return bits;
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| 134 | }
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| 135 |
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| 136 | /* Unpacks the next block and sets up for the inverse burrows-wheeler step. */
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| 137 |
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| 138 | static int get_next_block(bunzip_data *bd)
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| 139 | {
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| 140 | struct group_data *hufGroup;
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[1770] | 141 | int dbufCount, nextSym, dbufSize, groupCount, *base, *limit, selector,
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| 142 | i, j, k, t, runPos, symCount, symTotal, nSelectors, byteCount[256];
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[821] | 143 | unsigned char uc, symToByte[256], mtfSymbol[256], *selectors;
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[1770] | 144 | unsigned *dbuf, origPtr;
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[821] | 145 |
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[1770] | 146 | dbuf = bd->dbuf;
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| 147 | dbufSize = bd->dbufSize;
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| 148 | selectors = bd->selectors;
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[821] | 149 |
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| 150 | /* Reset longjmp I/O error handling */
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| 151 |
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[1770] | 152 | i = setjmp(bd->jmpbuf);
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| 153 | if (i) return i;
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[821] | 154 |
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| 155 | /* Read in header signature and CRC, then validate signature.
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| 156 | (last block signature means CRC is for whole file, return now) */
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| 157 |
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[1770] | 158 | i = get_bits(bd, 24);
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| 159 | j = get_bits(bd, 24);
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| 160 | bd->headerCRC = get_bits(bd, 32);
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[821] | 161 | if ((i == 0x177245) && (j == 0x385090)) return RETVAL_LAST_BLOCK;
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| 162 | if ((i != 0x314159) || (j != 0x265359)) return RETVAL_NOT_BZIP_DATA;
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| 163 |
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| 164 | /* We can add support for blockRandomised if anybody complains. There was
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| 165 | some code for this in busybox 1.0.0-pre3, but nobody ever noticed that
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| 166 | it didn't actually work. */
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| 167 |
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[1770] | 168 | if (get_bits(bd, 1)) return RETVAL_OBSOLETE_INPUT;
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| 169 | origPtr = get_bits(bd, 24);
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| 170 | if (origPtr > dbufSize) return RETVAL_DATA_ERROR;
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[821] | 171 |
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| 172 | /* mapping table: if some byte values are never used (encoding things
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| 173 | like ascii text), the compression code removes the gaps to have fewer
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| 174 | symbols to deal with, and writes a sparse bitfield indicating which
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| 175 | values were present. We make a translation table to convert the symbols
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| 176 | back to the corresponding bytes. */
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| 177 |
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[1770] | 178 | t = get_bits(bd, 16);
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| 179 | symTotal = 0;
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| 180 | for (i = 0; i < 16; i++) {
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| 181 | if (t & (1 << (15-i))) {
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| 182 | k = get_bits(bd, 16);
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| 183 | for (j = 0; j < 16; j++)
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| 184 | if (k & (1 << (15-j)))
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| 185 | symToByte[symTotal++] = (16*i) + j;
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[821] | 186 | }
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| 187 | }
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| 188 |
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| 189 | /* How many different Huffman coding groups does this block use? */
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| 190 |
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[1770] | 191 | groupCount = get_bits(bd, 3);
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| 192 | if (groupCount < 2 || groupCount > MAX_GROUPS)
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| 193 | return RETVAL_DATA_ERROR;
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[821] | 194 |
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| 195 | /* nSelectors: Every GROUP_SIZE many symbols we select a new Huffman coding
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| 196 | group. Read in the group selector list, which is stored as MTF encoded
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| 197 | bit runs. (MTF=Move To Front, as each value is used it's moved to the
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| 198 | start of the list.) */
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| 199 |
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[1770] | 200 | nSelectors = get_bits(bd, 15);
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| 201 | if (!nSelectors) return RETVAL_DATA_ERROR;
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| 202 | for (i = 0; i < groupCount; i++) mtfSymbol[i] = i;
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| 203 | for (i = 0; i < nSelectors; i++) {
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[821] | 204 |
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| 205 | /* Get next value */
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| 206 |
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[1770] | 207 | for (j = 0; get_bits(bd, 1); j++)
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| 208 | if (j>=groupCount) return RETVAL_DATA_ERROR;
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[821] | 209 |
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| 210 | /* Decode MTF to get the next selector */
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| 211 |
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| 212 | uc = mtfSymbol[j];
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[1770] | 213 | for (;j;j--) mtfSymbol[j] = mtfSymbol[j-1];
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| 214 | mtfSymbol[0] = selectors[i] = uc;
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[821] | 215 | }
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| 216 |
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| 217 | /* Read the Huffman coding tables for each group, which code for symTotal
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| 218 | literal symbols, plus two run symbols (RUNA, RUNB) */
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| 219 |
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[1770] | 220 | symCount = symTotal + 2;
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| 221 | for (j = 0; j < groupCount; j++) {
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| 222 | unsigned char length[MAX_SYMBOLS], temp[MAX_HUFCODE_BITS+1];
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| 223 | int minLen, maxLen, pp;
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[821] | 224 |
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| 225 | /* Read Huffman code lengths for each symbol. They're stored in
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| 226 | a way similar to mtf; record a starting value for the first symbol,
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| 227 | and an offset from the previous value for everys symbol after that.
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| 228 | (Subtracting 1 before the loop and then adding it back at the end is
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| 229 | an optimization that makes the test inside the loop simpler: symbol
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| 230 | length 0 becomes negative, so an unsigned inequality catches it.) */
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| 231 |
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[1770] | 232 | t = get_bits(bd, 5) - 1;
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[821] | 233 | for (i = 0; i < symCount; i++) {
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[1770] | 234 | for (;;) {
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| 235 | if ((unsigned)t > (MAX_HUFCODE_BITS-1))
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[821] | 236 | return RETVAL_DATA_ERROR;
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| 237 |
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| 238 | /* If first bit is 0, stop. Else second bit indicates whether
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| 239 | to increment or decrement the value. Optimization: grab 2
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| 240 | bits and unget the second if the first was 0. */
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| 241 |
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[1770] | 242 | k = get_bits(bd, 2);
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[821] | 243 | if (k < 2) {
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| 244 | bd->inbufBitCount++;
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| 245 | break;
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| 246 | }
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| 247 |
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| 248 | /* Add one if second bit 1, else subtract 1. Avoids if/else */
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| 249 |
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[1770] | 250 | t += (((k+1) & 2) - 1);
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[821] | 251 | }
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| 252 |
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| 253 | /* Correct for the initial -1, to get the final symbol length */
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| 254 |
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[1770] | 255 | length[i] = t + 1;
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[821] | 256 | }
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| 257 |
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| 258 | /* Find largest and smallest lengths in this group */
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| 259 |
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[1770] | 260 | minLen = maxLen = length[0];
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| 261 | for (i = 1; i < symCount; i++) {
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| 262 | if (length[i] > maxLen) maxLen = length[i];
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| 263 | else if (length[i] < minLen) minLen = length[i];
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[821] | 264 | }
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| 265 |
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| 266 | /* Calculate permute[], base[], and limit[] tables from length[].
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| 267 | *
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| 268 | * permute[] is the lookup table for converting Huffman coded symbols
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| 269 | * into decoded symbols. base[] is the amount to subtract from the
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| 270 | * value of a Huffman symbol of a given length when using permute[].
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| 271 | *
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| 272 | * limit[] indicates the largest numerical value a symbol with a given
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| 273 | * number of bits can have. This is how the Huffman codes can vary in
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| 274 | * length: each code with a value>limit[length] needs another bit.
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| 275 | */
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| 276 |
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[1770] | 277 | hufGroup = bd->groups + j;
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[821] | 278 | hufGroup->minLen = minLen;
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| 279 | hufGroup->maxLen = maxLen;
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| 280 |
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| 281 | /* Note that minLen can't be smaller than 1, so we adjust the base
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| 282 | and limit array pointers so we're not always wasting the first
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| 283 | entry. We do this again when using them (during symbol decoding).*/
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| 284 |
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[1770] | 285 | base = hufGroup->base - 1;
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| 286 | limit = hufGroup->limit - 1;
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[821] | 287 |
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| 288 | /* Calculate permute[]. Concurently, initialize temp[] and limit[]. */
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| 289 |
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[1770] | 290 | pp = 0;
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| 291 | for (i = minLen; i <= maxLen; i++) {
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| 292 | temp[i] = limit[i] = 0;
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| 293 | for (t = 0; t < symCount; t++)
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| 294 | if (length[t] == i)
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| 295 | hufGroup->permute[pp++] = t;
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[821] | 296 | }
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| 297 |
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| 298 | /* Count symbols coded for at each bit length */
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| 299 |
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[1770] | 300 | for (i = 0; i < symCount; i++) temp[length[i]]++;
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[821] | 301 |
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| 302 | /* Calculate limit[] (the largest symbol-coding value at each bit
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| 303 | * length, which is (previous limit<<1)+symbols at this level), and
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| 304 | * base[] (number of symbols to ignore at each bit length, which is
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| 305 | * limit minus the cumulative count of symbols coded for already). */
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| 306 |
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[1770] | 307 | pp = t = 0;
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| 308 | for (i = minLen; i < maxLen; i++) {
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| 309 | pp += temp[i];
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[821] | 310 |
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| 311 | /* We read the largest possible symbol size and then unget bits
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| 312 | after determining how many we need, and those extra bits could
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| 313 | be set to anything. (They're noise from future symbols.) At
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| 314 | each level we're really only interested in the first few bits,
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| 315 | so here we set all the trailing to-be-ignored bits to 1 so they
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| 316 | don't affect the value>limit[length] comparison. */
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| 317 |
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[1770] | 318 | limit[i] = (pp << (maxLen - i)) - 1;
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| 319 | pp <<= 1;
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| 320 | t += temp[i];
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| 321 | base[i+1] = pp - t;
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[821] | 322 | }
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| 323 | limit[maxLen+1] = INT_MAX; /* Sentinal value for reading next sym. */
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[1770] | 324 | limit[maxLen] = pp + temp[maxLen] - 1;
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| 325 | base[minLen] = 0;
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[821] | 326 | }
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| 327 |
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| 328 | /* We've finished reading and digesting the block header. Now read this
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| 329 | block's Huffman coded symbols from the file and undo the Huffman coding
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| 330 | and run length encoding, saving the result into dbuf[dbufCount++]=uc */
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| 331 |
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| 332 | /* Initialize symbol occurrence counters and symbol Move To Front table */
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| 333 |
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[1770] | 334 | for (i = 0; i < 256; i++) {
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[821] | 335 | byteCount[i] = 0;
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[1770] | 336 | mtfSymbol[i] = (unsigned char)i;
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[821] | 337 | }
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| 338 |
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| 339 | /* Loop through compressed symbols. */
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| 340 |
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[1770] | 341 | runPos = dbufCount = selector = 0;
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| 342 | for (;;) {
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[821] | 343 |
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| 344 | /* fetch next Huffman coding group from list. */
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| 345 |
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[1770] | 346 | symCount = GROUP_SIZE - 1;
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| 347 | if (selector >= nSelectors) return RETVAL_DATA_ERROR;
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| 348 | hufGroup = bd->groups + selectors[selector++];
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| 349 | base = hufGroup->base - 1;
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| 350 | limit = hufGroup->limit - 1;
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| 351 | continue_this_group:
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[821] | 352 |
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| 353 | /* Read next Huffman-coded symbol. */
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| 354 |
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| 355 | /* Note: It is far cheaper to read maxLen bits and back up than it is
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| 356 | to read minLen bits and then an additional bit at a time, testing
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| 357 | as we go. Because there is a trailing last block (with file CRC),
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| 358 | there is no danger of the overread causing an unexpected EOF for a
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| 359 | valid compressed file. As a further optimization, we do the read
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| 360 | inline (falling back to a call to get_bits if the buffer runs
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| 361 | dry). The following (up to got_huff_bits:) is equivalent to
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[1770] | 362 | j = get_bits(bd, hufGroup->maxLen);
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[821] | 363 | */
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| 364 |
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[1770] | 365 | while (bd->inbufBitCount < hufGroup->maxLen) {
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| 366 | if (bd->inbufPos == bd->inbufCount) {
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| 367 | j = get_bits(bd, hufGroup->maxLen);
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[821] | 368 | goto got_huff_bits;
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| 369 | }
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[1770] | 370 | bd->inbufBits = (bd->inbufBits << 8) | bd->inbuf[bd->inbufPos++];
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| 371 | bd->inbufBitCount += 8;
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[821] | 372 | };
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[1770] | 373 | bd->inbufBitCount -= hufGroup->maxLen;
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| 374 | j = (bd->inbufBits >> bd->inbufBitCount) & ((1 << hufGroup->maxLen) - 1);
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[821] | 375 |
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[1770] | 376 | got_huff_bits:
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[821] | 377 |
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| 378 | /* Figure how how many bits are in next symbol and unget extras */
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| 379 |
|
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[1770] | 380 | i = hufGroup->minLen;
|
---|
| 381 | while (j > limit[i]) ++i;
|
---|
[821] | 382 | bd->inbufBitCount += (hufGroup->maxLen - i);
|
---|
| 383 |
|
---|
| 384 | /* Huffman decode value to get nextSym (with bounds checking) */
|
---|
| 385 |
|
---|
[1770] | 386 | if (i > hufGroup->maxLen)
|
---|
[821] | 387 | return RETVAL_DATA_ERROR;
|
---|
[1770] | 388 | j = (j >> (hufGroup->maxLen - i)) - base[i];
|
---|
| 389 | if ((unsigned)j >= MAX_SYMBOLS)
|
---|
| 390 | return RETVAL_DATA_ERROR;
|
---|
[821] | 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 |
|
---|
[1770] | 398 | if ((unsigned)nextSym <= SYMBOL_RUNB) { /* RUNA or RUNB */
|
---|
[821] | 399 |
|
---|
| 400 | /* If this is the start of a new run, zero out counter */
|
---|
| 401 |
|
---|
[1770] | 402 | if (!runPos) {
|
---|
[821] | 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 */
|
---|
[1770] | 416 | if (runPos < dbufSize) runPos <<= 1;
|
---|
[821] | 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 |
|
---|
[1770] | 425 | if (runPos) {
|
---|
| 426 | runPos = 0;
|
---|
| 427 | if (dbufCount + t >= dbufSize) return RETVAL_DATA_ERROR;
|
---|
[821] | 428 |
|
---|
| 429 | uc = symToByte[mtfSymbol[0]];
|
---|
| 430 | byteCount[uc] += t;
|
---|
[1770] | 431 | while (t--) dbuf[dbufCount++] = uc;
|
---|
[821] | 432 | }
|
---|
| 433 |
|
---|
| 434 | /* Is this the terminating symbol? */
|
---|
| 435 |
|
---|
[1770] | 436 | if (nextSym > symTotal) break;
|
---|
[821] | 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 |
|
---|
[1770] | 446 | if (dbufCount >= dbufSize) return RETVAL_DATA_ERROR;
|
---|
[821] | 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;
|
---|
[1770] | 459 | uc = symToByte[uc];
|
---|
[821] | 460 |
|
---|
| 461 | /* We have our literal byte. Save it into dbuf. */
|
---|
| 462 |
|
---|
| 463 | byteCount[uc]++;
|
---|
[1770] | 464 | dbuf[dbufCount++] = (unsigned)uc;
|
---|
[821] | 465 |
|
---|
| 466 | /* Skip group initialization if we're not done with this group. Done
|
---|
| 467 | * this way to avoid compiler warning. */
|
---|
| 468 |
|
---|
[1770] | 469 | end_of_huffman_loop:
|
---|
| 470 | if (symCount--) goto continue_this_group;
|
---|
[821] | 471 | }
|
---|
| 472 |
|
---|
| 473 | /* At this point, we've read all the Huffman-coded symbols (and repeated
|
---|
[1770] | 474 | runs) for this block from the input stream, and decoded them into the
|
---|
[821] | 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 |
|
---|
[1770] | 482 | j = 0;
|
---|
| 483 | for (i = 0; i < 256; i++) {
|
---|
| 484 | k = j + byteCount[i];
|
---|
[821] | 485 | byteCount[i] = j;
|
---|
[1770] | 486 | j = k;
|
---|
[821] | 487 | }
|
---|
| 488 |
|
---|
| 489 | /* Figure out what order dbuf would be in if we sorted it. */
|
---|
| 490 |
|
---|
[1770] | 491 | for (i = 0; i < dbufCount; i++) {
|
---|
| 492 | uc = (unsigned char)(dbuf[i] & 0xff);
|
---|
[821] | 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 |
|
---|
[1770] | 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;
|
---|
[821] | 507 | }
|
---|
[1770] | 508 | bd->writeCount = dbufCount;
|
---|
[821] | 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 |
|
---|
[1770] | 520 | int read_bunzip(bunzip_data *bd, char *outbuf, int len)
|
---|
[821] | 521 | {
|
---|
[1770] | 522 | const unsigned *dbuf;
|
---|
| 523 | int pos, current, previous, gotcount;
|
---|
[821] | 524 |
|
---|
| 525 | /* If last read was short due to end of file, return last block now */
|
---|
[1770] | 526 | if (bd->writeCount < 0) return bd->writeCount;
|
---|
[821] | 527 |
|
---|
| 528 | gotcount = 0;
|
---|
[1770] | 529 | dbuf = bd->dbuf;
|
---|
| 530 | pos = bd->writePos;
|
---|
| 531 | current = bd->writeCurrent;
|
---|
[821] | 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 |
|
---|
[1770] | 545 | for (;;) {
|
---|
[821] | 546 |
|
---|
| 547 | /* If the output buffer is full, snapshot state and return */
|
---|
| 548 |
|
---|
[1770] | 549 | if (gotcount >= len) {
|
---|
| 550 | bd->writePos =pos;
|
---|
| 551 | bd->writeCurrent = current;
|
---|
[821] | 552 | bd->writeCopies++;
|
---|
| 553 | return len;
|
---|
| 554 | }
|
---|
| 555 |
|
---|
| 556 | /* Write next byte into output buffer, updating CRC */
|
---|
| 557 |
|
---|
| 558 | outbuf[gotcount++] = current;
|
---|
[1770] | 559 | bd->writeCRC = (bd->writeCRC << 8)
|
---|
| 560 | ^ bd->crc32Table[(bd->writeCRC >> 24) ^ current];
|
---|
[821] | 561 |
|
---|
| 562 | /* Loop now if we're outputting multiple copies of this byte */
|
---|
| 563 |
|
---|
| 564 | if (bd->writeCopies) {
|
---|
| 565 | --bd->writeCopies;
|
---|
| 566 | continue;
|
---|
| 567 | }
|
---|
[1770] | 568 | decode_next_byte:
|
---|
[821] | 569 | if (!bd->writeCount--) break;
|
---|
| 570 | /* Follow sequence vector to undo Burrows-Wheeler transform */
|
---|
[1770] | 571 | previous = current;
|
---|
| 572 | pos = dbuf[pos];
|
---|
| 573 | current = pos & 0xff;
|
---|
| 574 | pos >>= 8;
|
---|
[821] | 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 |
|
---|
[1770] | 580 | if (--bd->writeRunCountdown) {
|
---|
| 581 | if (current != previous)
|
---|
| 582 | bd->writeRunCountdown = 4;
|
---|
[821] | 583 | } else {
|
---|
| 584 |
|
---|
| 585 | /* We have a repeated run, this byte indicates the count */
|
---|
| 586 |
|
---|
[1770] | 587 | bd->writeCopies = current;
|
---|
| 588 | current = previous;
|
---|
| 589 | bd->writeRunCountdown = 5;
|
---|
[821] | 590 |
|
---|
| 591 | /* Sometimes there are just 3 bytes (run length 0) */
|
---|
| 592 |
|
---|
[1770] | 593 | if (!bd->writeCopies) goto decode_next_byte;
|
---|
[821] | 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 |
|
---|
[1770] | 603 | bd->writeCRC = ~bd->writeCRC;
|
---|
| 604 | bd->totalCRC = ((bd->totalCRC << 1) | (bd->totalCRC >> 31)) ^ bd->writeCRC;
|
---|
[821] | 605 |
|
---|
| 606 | /* If this block had a CRC error, force file level CRC error. */
|
---|
| 607 |
|
---|
[1770] | 608 | if (bd->writeCRC != bd->headerCRC) {
|
---|
| 609 | bd->totalCRC = bd->headerCRC+1;
|
---|
[821] | 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 |
|
---|
[1770] | 617 | previous = get_next_block(bd);
|
---|
| 618 | if (previous) {
|
---|
| 619 | bd->writeCount = previous;
|
---|
| 620 | return (previous != RETVAL_LAST_BLOCK) ? previous : gotcount;
|
---|
[821] | 621 | }
|
---|
[1770] | 622 | bd->writeCRC = ~0;
|
---|
| 623 | pos = bd->writePos;
|
---|
| 624 | current = bd->writeCurrent;
|
---|
[821] | 625 | goto decode_next_byte;
|
---|
| 626 | }
|
---|
| 627 |
|
---|
[1770] | 628 |
|
---|
[821] | 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 |
|
---|
[1770] | 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,
|
---|
[821] | 638 | int len)
|
---|
| 639 | {
|
---|
| 640 | bunzip_data *bd;
|
---|
[1770] | 641 | unsigned i;
|
---|
| 642 | enum {
|
---|
| 643 | BZh0 = ('B' << 24) + ('Z' << 16) + ('h' << 8) + '0'
|
---|
| 644 | };
|
---|
[821] | 645 |
|
---|
| 646 | /* Figure out how much data to allocate */
|
---|
| 647 |
|
---|
[1770] | 648 | i = sizeof(bunzip_data);
|
---|
| 649 | if (in_fd != -1) i += IOBUF_SIZE;
|
---|
[821] | 650 |
|
---|
| 651 | /* Allocate bunzip_data. Most fields initialize to zero. */
|
---|
| 652 |
|
---|
[1770] | 653 | bd = *bdp = xzalloc(i);
|
---|
[821] | 654 |
|
---|
| 655 | /* Setup input buffer */
|
---|
| 656 |
|
---|
[1770] | 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);
|
---|
[821] | 664 |
|
---|
| 665 | /* Init the CRC32 table (big endian) */
|
---|
| 666 |
|
---|
[1770] | 667 | crc32_filltable(bd->crc32Table, 1);
|
---|
[821] | 668 |
|
---|
| 669 | /* Setup for I/O error handling via longjmp */
|
---|
| 670 |
|
---|
[1770] | 671 | i = setjmp(bd->jmpbuf);
|
---|
| 672 | if (i) return i;
|
---|
[821] | 673 |
|
---|
| 674 | /* Ensure that file starts with "BZh['1'-'9']." */
|
---|
| 675 |
|
---|
[1770] | 676 | i = get_bits(bd, 32);
|
---|
| 677 | if ((unsigned)(i - BZh0 - 1) >= 9) return RETVAL_NOT_BZIP_DATA;
|
---|
[821] | 678 |
|
---|
| 679 | /* Fourth byte (ascii '1'-'9'), indicates block size in units of 100k of
|
---|
| 680 | uncompressed data. Allocate intermediate buffer for block. */
|
---|
| 681 |
|
---|
[1770] | 682 | bd->dbufSize = 100000 * (i - BZh0);
|
---|
[821] | 683 |
|
---|
[1770] | 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 | }
|
---|
[821] | 690 | return RETVAL_OK;
|
---|
| 691 | }
|
---|
| 692 |
|
---|
[1770] | 693 | void dealloc_bunzip(bunzip_data *bd)
|
---|
| 694 | {
|
---|
| 695 | free(bd->dbuf);
|
---|
| 696 | free(bd);
|
---|
| 697 | }
|
---|
[821] | 698 |
|
---|
[1770] | 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)
|
---|
[821] | 704 | {
|
---|
[1770] | 705 | USE_DESKTOP(long long total_written = 0;)
|
---|
[821] | 706 | char *outbuf;
|
---|
| 707 | bunzip_data *bd;
|
---|
| 708 | int i;
|
---|
| 709 |
|
---|
[1770] | 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;
|
---|
[821] | 718 | break;
|
---|
| 719 | }
|
---|
[1770] | 720 | USE_DESKTOP(total_written += i;)
|
---|
[821] | 721 | }
|
---|
| 722 | }
|
---|
| 723 |
|
---|
| 724 | /* Check CRC and release memory */
|
---|
| 725 |
|
---|
[1770] | 726 | if (i == RETVAL_LAST_BLOCK) {
|
---|
| 727 | if (bd->headerCRC != bd->totalCRC) {
|
---|
| 728 | bb_error_msg("data integrity error when decompressing");
|
---|
[821] | 729 | } else {
|
---|
[1770] | 730 | i = RETVAL_OK;
|
---|
[821] | 731 | }
|
---|
[1770] | 732 | } else if (i == RETVAL_UNEXPECTED_OUTPUT_EOF) {
|
---|
| 733 | bb_error_msg("compressed file ends unexpectedly");
|
---|
[821] | 734 | } else {
|
---|
[1770] | 735 | bb_error_msg("decompression failed");
|
---|
[821] | 736 | }
|
---|
[1770] | 737 | dealloc_bunzip(bd);
|
---|
[821] | 738 | free(outbuf);
|
---|
| 739 |
|
---|
[1770] | 740 | return i ? i : USE_DESKTOP(total_written) + 0;
|
---|
[821] | 741 | }
|
---|
| 742 |
|
---|
| 743 | #ifdef TESTING
|
---|
| 744 |
|
---|
[1770] | 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 | };
|
---|
[821] | 750 |
|
---|
| 751 | /* Dumb little test thing, decompress stdin to stdout */
|
---|
[1770] | 752 | int main(int argc, char **argv)
|
---|
[821] | 753 | {
|
---|
[1770] | 754 | int i = unpack_bz2_stream(0, 1);
|
---|
[821] | 755 | char c;
|
---|
| 756 |
|
---|
[1770] | 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");
|
---|
[821] | 761 | return -i;
|
---|
| 762 | }
|
---|
| 763 | #endif
|
---|