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![Paul Bolle](/assets/img/avatar_default.png)
Signed-off-by: Paul Bolle <pebolle@tiscali.nl> Signed-off-by: Jiri Kosina <jkosina@suse.cz>
755 lines
23 KiB
C
755 lines
23 KiB
C
/* Small bzip2 deflate implementation, by Rob Landley (rob@landley.net).
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Based on bzip2 decompression code by Julian R Seward (jseward@acm.org),
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which also acknowledges contributions by Mike Burrows, David Wheeler,
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Peter Fenwick, Alistair Moffat, Radford Neal, Ian H. Witten,
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Robert Sedgewick, and Jon L. Bentley.
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This code is licensed under the LGPLv2:
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LGPL (http://www.gnu.org/copyleft/lgpl.html
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*/
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/*
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Size and speed optimizations by Manuel Novoa III (mjn3@codepoet.org).
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More efficient reading of Huffman codes, a streamlined read_bunzip()
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function, and various other tweaks. In (limited) tests, approximately
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20% faster than bzcat on x86 and about 10% faster on arm.
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Note that about 2/3 of the time is spent in read_unzip() reversing
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the Burrows-Wheeler transformation. Much of that time is delay
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resulting from cache misses.
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I would ask that anyone benefiting from this work, especially those
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using it in commercial products, consider making a donation to my local
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non-profit hospice organization in the name of the woman I loved, who
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passed away Feb. 12, 2003.
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In memory of Toni W. Hagan
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Hospice of Acadiana, Inc.
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2600 Johnston St., Suite 200
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Lafayette, LA 70503-3240
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Phone (337) 232-1234 or 1-800-738-2226
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Fax (337) 232-1297
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http://www.hospiceacadiana.com/
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Manuel
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*/
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/*
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Made it fit for running in Linux Kernel by Alain Knaff (alain@knaff.lu)
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*/
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#ifdef STATIC
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#define PREBOOT
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#else
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#include <linux/decompress/bunzip2.h>
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#endif /* STATIC */
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#include <linux/decompress/mm.h>
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#ifndef INT_MAX
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#define INT_MAX 0x7fffffff
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#endif
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/* Constants for Huffman coding */
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#define MAX_GROUPS 6
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#define GROUP_SIZE 50 /* 64 would have been more efficient */
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#define MAX_HUFCODE_BITS 20 /* Longest Huffman code allowed */
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#define MAX_SYMBOLS 258 /* 256 literals + RUNA + RUNB */
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#define SYMBOL_RUNA 0
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#define SYMBOL_RUNB 1
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/* Status return values */
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#define RETVAL_OK 0
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#define RETVAL_LAST_BLOCK (-1)
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#define RETVAL_NOT_BZIP_DATA (-2)
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#define RETVAL_UNEXPECTED_INPUT_EOF (-3)
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#define RETVAL_UNEXPECTED_OUTPUT_EOF (-4)
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#define RETVAL_DATA_ERROR (-5)
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#define RETVAL_OUT_OF_MEMORY (-6)
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#define RETVAL_OBSOLETE_INPUT (-7)
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/* Other housekeeping constants */
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#define BZIP2_IOBUF_SIZE 4096
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/* This is what we know about each Huffman coding group */
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struct group_data {
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/* We have an extra slot at the end of limit[] for a sentinal value. */
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int limit[MAX_HUFCODE_BITS+1];
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int base[MAX_HUFCODE_BITS];
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int permute[MAX_SYMBOLS];
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int minLen, maxLen;
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};
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/* Structure holding all the housekeeping data, including IO buffers and
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memory that persists between calls to bunzip */
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struct bunzip_data {
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/* State for interrupting output loop */
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int writeCopies, writePos, writeRunCountdown, writeCount, writeCurrent;
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/* I/O tracking data (file handles, buffers, positions, etc.) */
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int (*fill)(void*, unsigned int);
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int inbufCount, inbufPos /*, outbufPos*/;
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unsigned char *inbuf /*,*outbuf*/;
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unsigned int inbufBitCount, inbufBits;
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/* The CRC values stored in the block header and calculated from the
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data */
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unsigned int crc32Table[256], headerCRC, totalCRC, writeCRC;
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/* Intermediate buffer and its size (in bytes) */
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unsigned int *dbuf, dbufSize;
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/* These things are a bit too big to go on the stack */
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unsigned char selectors[32768]; /* nSelectors = 15 bits */
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struct group_data groups[MAX_GROUPS]; /* Huffman coding tables */
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int io_error; /* non-zero if we have IO error */
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int byteCount[256];
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unsigned char symToByte[256], mtfSymbol[256];
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};
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/* Return the next nnn bits of input. All reads from the compressed input
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are done through this function. All reads are big endian */
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static unsigned int INIT get_bits(struct bunzip_data *bd, char bits_wanted)
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{
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unsigned int bits = 0;
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/* If we need to get more data from the byte buffer, do so.
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(Loop getting one byte at a time to enforce endianness and avoid
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unaligned access.) */
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while (bd->inbufBitCount < bits_wanted) {
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/* If we need to read more data from file into byte buffer, do
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so */
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if (bd->inbufPos == bd->inbufCount) {
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if (bd->io_error)
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return 0;
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bd->inbufCount = bd->fill(bd->inbuf, BZIP2_IOBUF_SIZE);
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if (bd->inbufCount <= 0) {
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bd->io_error = RETVAL_UNEXPECTED_INPUT_EOF;
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return 0;
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}
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bd->inbufPos = 0;
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}
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/* Avoid 32-bit overflow (dump bit buffer to top of output) */
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if (bd->inbufBitCount >= 24) {
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bits = bd->inbufBits&((1 << bd->inbufBitCount)-1);
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bits_wanted -= bd->inbufBitCount;
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bits <<= bits_wanted;
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bd->inbufBitCount = 0;
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}
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/* Grab next 8 bits of input from buffer. */
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bd->inbufBits = (bd->inbufBits << 8)|bd->inbuf[bd->inbufPos++];
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bd->inbufBitCount += 8;
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}
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/* Calculate result */
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bd->inbufBitCount -= bits_wanted;
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bits |= (bd->inbufBits >> bd->inbufBitCount)&((1 << bits_wanted)-1);
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return bits;
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}
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/* Unpacks the next block and sets up for the inverse burrows-wheeler step. */
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static int INIT get_next_block(struct bunzip_data *bd)
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{
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struct group_data *hufGroup = NULL;
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int *base = NULL;
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int *limit = NULL;
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int dbufCount, nextSym, dbufSize, groupCount, selector,
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i, j, k, t, runPos, symCount, symTotal, nSelectors, *byteCount;
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unsigned char uc, *symToByte, *mtfSymbol, *selectors;
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unsigned int *dbuf, origPtr;
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dbuf = bd->dbuf;
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dbufSize = bd->dbufSize;
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selectors = bd->selectors;
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byteCount = bd->byteCount;
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symToByte = bd->symToByte;
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mtfSymbol = bd->mtfSymbol;
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/* Read in header signature and CRC, then validate signature.
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(last block signature means CRC is for whole file, return now) */
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i = get_bits(bd, 24);
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j = get_bits(bd, 24);
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bd->headerCRC = get_bits(bd, 32);
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if ((i == 0x177245) && (j == 0x385090))
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return RETVAL_LAST_BLOCK;
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if ((i != 0x314159) || (j != 0x265359))
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return RETVAL_NOT_BZIP_DATA;
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/* We can add support for blockRandomised if anybody complains.
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There was some code for this in busybox 1.0.0-pre3, but nobody ever
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noticed that it didn't actually work. */
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if (get_bits(bd, 1))
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return RETVAL_OBSOLETE_INPUT;
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origPtr = get_bits(bd, 24);
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if (origPtr > dbufSize)
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return RETVAL_DATA_ERROR;
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/* mapping table: if some byte values are never used (encoding things
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like ascii text), the compression code removes the gaps to have fewer
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symbols to deal with, and writes a sparse bitfield indicating which
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values were present. We make a translation table to convert the
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symbols back to the corresponding bytes. */
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t = get_bits(bd, 16);
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symTotal = 0;
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for (i = 0; i < 16; i++) {
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if (t&(1 << (15-i))) {
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k = get_bits(bd, 16);
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for (j = 0; j < 16; j++)
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if (k&(1 << (15-j)))
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symToByte[symTotal++] = (16*i)+j;
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}
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}
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/* How many different Huffman coding groups does this block use? */
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groupCount = get_bits(bd, 3);
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if (groupCount < 2 || groupCount > MAX_GROUPS)
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return RETVAL_DATA_ERROR;
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/* nSelectors: Every GROUP_SIZE many symbols we select a new
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Huffman coding group. Read in the group selector list,
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which is stored as MTF encoded bit runs. (MTF = Move To
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Front, as each value is used it's moved to the start of the
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list.) */
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nSelectors = get_bits(bd, 15);
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if (!nSelectors)
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return RETVAL_DATA_ERROR;
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for (i = 0; i < groupCount; i++)
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mtfSymbol[i] = i;
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for (i = 0; i < nSelectors; i++) {
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/* Get next value */
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for (j = 0; get_bits(bd, 1); j++)
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if (j >= groupCount)
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return RETVAL_DATA_ERROR;
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/* Decode MTF to get the next selector */
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uc = mtfSymbol[j];
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for (; j; j--)
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mtfSymbol[j] = mtfSymbol[j-1];
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mtfSymbol[0] = selectors[i] = uc;
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}
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/* Read the Huffman coding tables for each group, which code
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for symTotal literal symbols, plus two run symbols (RUNA,
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RUNB) */
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symCount = symTotal+2;
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for (j = 0; j < groupCount; j++) {
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unsigned char length[MAX_SYMBOLS], temp[MAX_HUFCODE_BITS+1];
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int minLen, maxLen, pp;
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/* Read Huffman code lengths for each symbol. They're
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stored in a way similar to mtf; record a starting
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value for the first symbol, and an offset from the
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previous value for everys symbol after that.
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(Subtracting 1 before the loop and then adding it
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back at the end is an optimization that makes the
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test inside the loop simpler: symbol length 0
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becomes negative, so an unsigned inequality catches
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it.) */
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t = get_bits(bd, 5)-1;
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for (i = 0; i < symCount; i++) {
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for (;;) {
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if (((unsigned)t) > (MAX_HUFCODE_BITS-1))
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return RETVAL_DATA_ERROR;
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/* If first bit is 0, stop. Else
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second bit indicates whether to
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increment or decrement the value.
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Optimization: grab 2 bits and unget
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the second if the first was 0. */
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k = get_bits(bd, 2);
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if (k < 2) {
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bd->inbufBitCount++;
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break;
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}
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/* Add one if second bit 1, else
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* subtract 1. Avoids if/else */
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t += (((k+1)&2)-1);
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}
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/* Correct for the initial -1, to get the
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* final symbol length */
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length[i] = t+1;
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}
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/* Find largest and smallest lengths in this group */
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minLen = maxLen = length[0];
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for (i = 1; i < symCount; i++) {
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if (length[i] > maxLen)
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maxLen = length[i];
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else if (length[i] < minLen)
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minLen = length[i];
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}
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/* Calculate permute[], base[], and limit[] tables from
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* length[].
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*
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* permute[] is the lookup table for converting
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* Huffman coded symbols into decoded symbols. base[]
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* is the amount to subtract from the value of a
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* Huffman symbol of a given length when using
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* permute[].
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*
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* limit[] indicates the largest numerical value a
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* symbol with a given number of bits can have. This
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* is how the Huffman codes can vary in length: each
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* code with a value > limit[length] needs another
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* bit.
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*/
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hufGroup = bd->groups+j;
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hufGroup->minLen = minLen;
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hufGroup->maxLen = maxLen;
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/* Note that minLen can't be smaller than 1, so we
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adjust the base and limit array pointers so we're
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not always wasting the first entry. We do this
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again when using them (during symbol decoding).*/
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base = hufGroup->base-1;
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limit = hufGroup->limit-1;
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/* Calculate permute[]. Concurrently, initialize
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* temp[] and limit[]. */
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pp = 0;
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for (i = minLen; i <= maxLen; i++) {
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temp[i] = limit[i] = 0;
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for (t = 0; t < symCount; t++)
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if (length[t] == i)
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hufGroup->permute[pp++] = t;
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}
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/* Count symbols coded for at each bit length */
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for (i = 0; i < symCount; i++)
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temp[length[i]]++;
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/* Calculate limit[] (the largest symbol-coding value
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*at each bit length, which is (previous limit <<
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*1)+symbols at this level), and base[] (number of
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*symbols to ignore at each bit length, which is limit
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*minus the cumulative count of symbols coded for
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*already). */
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pp = t = 0;
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for (i = minLen; i < maxLen; i++) {
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pp += temp[i];
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/* We read the largest possible symbol size
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and then unget bits after determining how
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many we need, and those extra bits could be
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set to anything. (They're noise from
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future symbols.) At each level we're
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really only interested in the first few
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bits, so here we set all the trailing
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to-be-ignored bits to 1 so they don't
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affect the value > limit[length]
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comparison. */
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limit[i] = (pp << (maxLen - i)) - 1;
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pp <<= 1;
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base[i+1] = pp-(t += temp[i]);
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}
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limit[maxLen+1] = INT_MAX; /* Sentinal value for
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* reading next sym. */
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limit[maxLen] = pp+temp[maxLen]-1;
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base[minLen] = 0;
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}
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/* We've finished reading and digesting the block header. Now
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read this block's Huffman coded symbols from the file and
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undo the Huffman coding and run length encoding, saving the
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result into dbuf[dbufCount++] = uc */
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/* Initialize symbol occurrence counters and symbol Move To
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* Front table */
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for (i = 0; i < 256; i++) {
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byteCount[i] = 0;
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mtfSymbol[i] = (unsigned char)i;
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}
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/* Loop through compressed symbols. */
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runPos = dbufCount = symCount = selector = 0;
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for (;;) {
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/* Determine which Huffman coding group to use. */
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if (!(symCount--)) {
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symCount = GROUP_SIZE-1;
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if (selector >= nSelectors)
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return RETVAL_DATA_ERROR;
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hufGroup = bd->groups+selectors[selector++];
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base = hufGroup->base-1;
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limit = hufGroup->limit-1;
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}
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/* Read next Huffman-coded symbol. */
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/* Note: It is far cheaper to read maxLen bits and
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back up than it is to read minLen bits and then an
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additional bit at a time, testing as we go.
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Because there is a trailing last block (with file
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CRC), there is no danger of the overread causing an
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unexpected EOF for a valid compressed file. As a
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further optimization, we do the read inline
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(falling back to a call to get_bits if the buffer
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runs dry). The following (up to got_huff_bits:) is
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equivalent to j = get_bits(bd, hufGroup->maxLen);
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*/
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while (bd->inbufBitCount < hufGroup->maxLen) {
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if (bd->inbufPos == bd->inbufCount) {
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j = get_bits(bd, hufGroup->maxLen);
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goto got_huff_bits;
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}
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bd->inbufBits =
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(bd->inbufBits << 8)|bd->inbuf[bd->inbufPos++];
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bd->inbufBitCount += 8;
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};
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bd->inbufBitCount -= hufGroup->maxLen;
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j = (bd->inbufBits >> bd->inbufBitCount)&
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((1 << hufGroup->maxLen)-1);
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got_huff_bits:
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/* Figure how how many bits are in next symbol and
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* unget extras */
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i = hufGroup->minLen;
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while (j > limit[i])
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++i;
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bd->inbufBitCount += (hufGroup->maxLen - i);
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/* Huffman decode value to get nextSym (with bounds checking) */
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if ((i > hufGroup->maxLen)
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|| (((unsigned)(j = (j>>(hufGroup->maxLen-i))-base[i]))
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>= MAX_SYMBOLS))
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return RETVAL_DATA_ERROR;
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nextSym = hufGroup->permute[j];
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/* We have now decoded the symbol, which indicates
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either a new literal byte, or a repeated run of the
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most recent literal byte. First, check if nextSym
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indicates a repeated run, and if so loop collecting
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how many times to repeat the last literal. */
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if (((unsigned)nextSym) <= SYMBOL_RUNB) { /* RUNA or RUNB */
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/* If this is the start of a new run, zero out
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* counter */
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if (!runPos) {
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runPos = 1;
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t = 0;
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}
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/* Neat trick that saves 1 symbol: instead of
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or-ing 0 or 1 at each bit position, add 1
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or 2 instead. For example, 1011 is 1 << 0
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+ 1 << 1 + 2 << 2. 1010 is 2 << 0 + 2 << 1
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+ 1 << 2. You can make any bit pattern
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that way using 1 less symbol than the basic
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or 0/1 method (except all bits 0, which
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would use no symbols, but a run of length 0
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doesn't mean anything in this context).
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Thus space is saved. */
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t += (runPos << nextSym);
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/* +runPos if RUNA; +2*runPos if RUNB */
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runPos <<= 1;
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continue;
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}
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/* When we hit the first non-run symbol after a run,
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we now know how many times to repeat the last
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literal, so append that many copies to our buffer
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of decoded symbols (dbuf) now. (The last literal
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used is the one at the head of the mtfSymbol
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array.) */
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if (runPos) {
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runPos = 0;
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if (dbufCount+t >= dbufSize)
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return RETVAL_DATA_ERROR;
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uc = symToByte[mtfSymbol[0]];
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byteCount[uc] += t;
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while (t--)
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dbuf[dbufCount++] = uc;
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}
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/* Is this the terminating symbol? */
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if (nextSym > symTotal)
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break;
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/* At this point, nextSym indicates a new literal
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character. Subtract one to get the position in the
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MTF array at which this literal is currently to be
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found. (Note that the result can't be -1 or 0,
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because 0 and 1 are RUNA and RUNB. But another
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instance of the first symbol in the mtf array,
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position 0, would have been handled as part of a
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run above. Therefore 1 unused mtf position minus 2
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non-literal nextSym values equals -1.) */
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if (dbufCount >= dbufSize)
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return RETVAL_DATA_ERROR;
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i = nextSym - 1;
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uc = mtfSymbol[i];
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/* Adjust the MTF array. Since we typically expect to
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*move only a small number of symbols, and are bound
|
|
*by 256 in any case, using memmove here would
|
|
*typically be bigger and slower due to function call
|
|
*overhead and other assorted setup costs. */
|
|
do {
|
|
mtfSymbol[i] = mtfSymbol[i-1];
|
|
} while (--i);
|
|
mtfSymbol[0] = uc;
|
|
uc = symToByte[uc];
|
|
/* We have our literal byte. Save it into dbuf. */
|
|
byteCount[uc]++;
|
|
dbuf[dbufCount++] = (unsigned int)uc;
|
|
}
|
|
/* At this point, we've read all the Huffman-coded symbols
|
|
(and repeated runs) for this block from the input stream,
|
|
and decoded them into the intermediate buffer. There are
|
|
dbufCount many decoded bytes in dbuf[]. Now undo the
|
|
Burrows-Wheeler transform on dbuf. See
|
|
http://dogma.net/markn/articles/bwt/bwt.htm
|
|
*/
|
|
/* Turn byteCount into cumulative occurrence counts of 0 to n-1. */
|
|
j = 0;
|
|
for (i = 0; i < 256; i++) {
|
|
k = j+byteCount[i];
|
|
byteCount[i] = j;
|
|
j = k;
|
|
}
|
|
/* Figure out what order dbuf would be in if we sorted it. */
|
|
for (i = 0; i < dbufCount; i++) {
|
|
uc = (unsigned char)(dbuf[i] & 0xff);
|
|
dbuf[byteCount[uc]] |= (i << 8);
|
|
byteCount[uc]++;
|
|
}
|
|
/* Decode first byte by hand to initialize "previous" byte.
|
|
Note that it doesn't get output, and if the first three
|
|
characters are identical it doesn't qualify as a run (hence
|
|
writeRunCountdown = 5). */
|
|
if (dbufCount) {
|
|
if (origPtr >= dbufCount)
|
|
return RETVAL_DATA_ERROR;
|
|
bd->writePos = dbuf[origPtr];
|
|
bd->writeCurrent = (unsigned char)(bd->writePos&0xff);
|
|
bd->writePos >>= 8;
|
|
bd->writeRunCountdown = 5;
|
|
}
|
|
bd->writeCount = dbufCount;
|
|
|
|
return RETVAL_OK;
|
|
}
|
|
|
|
/* Undo burrows-wheeler transform on intermediate buffer to produce output.
|
|
If start_bunzip was initialized with out_fd =-1, then up to len bytes of
|
|
data are written to outbuf. Return value is number of bytes written or
|
|
error (all errors are negative numbers). If out_fd!=-1, outbuf and len
|
|
are ignored, data is written to out_fd and return is RETVAL_OK or error.
|
|
*/
|
|
|
|
static int INIT read_bunzip(struct bunzip_data *bd, char *outbuf, int len)
|
|
{
|
|
const unsigned int *dbuf;
|
|
int pos, xcurrent, previous, gotcount;
|
|
|
|
/* If last read was short due to end of file, return last block now */
|
|
if (bd->writeCount < 0)
|
|
return bd->writeCount;
|
|
|
|
gotcount = 0;
|
|
dbuf = bd->dbuf;
|
|
pos = bd->writePos;
|
|
xcurrent = bd->writeCurrent;
|
|
|
|
/* We will always have pending decoded data to write into the output
|
|
buffer unless this is the very first call (in which case we haven't
|
|
Huffman-decoded a block into the intermediate buffer yet). */
|
|
|
|
if (bd->writeCopies) {
|
|
/* Inside the loop, writeCopies means extra copies (beyond 1) */
|
|
--bd->writeCopies;
|
|
/* Loop outputting bytes */
|
|
for (;;) {
|
|
/* If the output buffer is full, snapshot
|
|
* state and return */
|
|
if (gotcount >= len) {
|
|
bd->writePos = pos;
|
|
bd->writeCurrent = xcurrent;
|
|
bd->writeCopies++;
|
|
return len;
|
|
}
|
|
/* Write next byte into output buffer, updating CRC */
|
|
outbuf[gotcount++] = xcurrent;
|
|
bd->writeCRC = (((bd->writeCRC) << 8)
|
|
^bd->crc32Table[((bd->writeCRC) >> 24)
|
|
^xcurrent]);
|
|
/* Loop now if we're outputting multiple
|
|
* copies of this byte */
|
|
if (bd->writeCopies) {
|
|
--bd->writeCopies;
|
|
continue;
|
|
}
|
|
decode_next_byte:
|
|
if (!bd->writeCount--)
|
|
break;
|
|
/* Follow sequence vector to undo
|
|
* Burrows-Wheeler transform */
|
|
previous = xcurrent;
|
|
pos = dbuf[pos];
|
|
xcurrent = pos&0xff;
|
|
pos >>= 8;
|
|
/* After 3 consecutive copies of the same
|
|
byte, the 4th is a repeat count. We count
|
|
down from 4 instead *of counting up because
|
|
testing for non-zero is faster */
|
|
if (--bd->writeRunCountdown) {
|
|
if (xcurrent != previous)
|
|
bd->writeRunCountdown = 4;
|
|
} else {
|
|
/* We have a repeated run, this byte
|
|
* indicates the count */
|
|
bd->writeCopies = xcurrent;
|
|
xcurrent = previous;
|
|
bd->writeRunCountdown = 5;
|
|
/* Sometimes there are just 3 bytes
|
|
* (run length 0) */
|
|
if (!bd->writeCopies)
|
|
goto decode_next_byte;
|
|
/* Subtract the 1 copy we'd output
|
|
* anyway to get extras */
|
|
--bd->writeCopies;
|
|
}
|
|
}
|
|
/* Decompression of this block completed successfully */
|
|
bd->writeCRC = ~bd->writeCRC;
|
|
bd->totalCRC = ((bd->totalCRC << 1) |
|
|
(bd->totalCRC >> 31)) ^ bd->writeCRC;
|
|
/* If this block had a CRC error, force file level CRC error. */
|
|
if (bd->writeCRC != bd->headerCRC) {
|
|
bd->totalCRC = bd->headerCRC+1;
|
|
return RETVAL_LAST_BLOCK;
|
|
}
|
|
}
|
|
|
|
/* Refill the intermediate buffer by Huffman-decoding next
|
|
* block of input */
|
|
/* (previous is just a convenient unused temp variable here) */
|
|
previous = get_next_block(bd);
|
|
if (previous) {
|
|
bd->writeCount = previous;
|
|
return (previous != RETVAL_LAST_BLOCK) ? previous : gotcount;
|
|
}
|
|
bd->writeCRC = 0xffffffffUL;
|
|
pos = bd->writePos;
|
|
xcurrent = bd->writeCurrent;
|
|
goto decode_next_byte;
|
|
}
|
|
|
|
static int INIT nofill(void *buf, unsigned int len)
|
|
{
|
|
return -1;
|
|
}
|
|
|
|
/* Allocate the structure, read file header. If in_fd ==-1, inbuf must contain
|
|
a complete bunzip file (len bytes long). If in_fd!=-1, inbuf and len are
|
|
ignored, and data is read from file handle into temporary buffer. */
|
|
static int INIT start_bunzip(struct bunzip_data **bdp, void *inbuf, int len,
|
|
int (*fill)(void*, unsigned int))
|
|
{
|
|
struct bunzip_data *bd;
|
|
unsigned int i, j, c;
|
|
const unsigned int BZh0 =
|
|
(((unsigned int)'B') << 24)+(((unsigned int)'Z') << 16)
|
|
+(((unsigned int)'h') << 8)+(unsigned int)'0';
|
|
|
|
/* Figure out how much data to allocate */
|
|
i = sizeof(struct bunzip_data);
|
|
|
|
/* Allocate bunzip_data. Most fields initialize to zero. */
|
|
bd = *bdp = malloc(i);
|
|
if (!bd)
|
|
return RETVAL_OUT_OF_MEMORY;
|
|
memset(bd, 0, sizeof(struct bunzip_data));
|
|
/* Setup input buffer */
|
|
bd->inbuf = inbuf;
|
|
bd->inbufCount = len;
|
|
if (fill != NULL)
|
|
bd->fill = fill;
|
|
else
|
|
bd->fill = nofill;
|
|
|
|
/* Init the CRC32 table (big endian) */
|
|
for (i = 0; i < 256; i++) {
|
|
c = i << 24;
|
|
for (j = 8; j; j--)
|
|
c = c&0x80000000 ? (c << 1)^0x04c11db7 : (c << 1);
|
|
bd->crc32Table[i] = c;
|
|
}
|
|
|
|
/* Ensure that file starts with "BZh['1'-'9']." */
|
|
i = get_bits(bd, 32);
|
|
if (((unsigned int)(i-BZh0-1)) >= 9)
|
|
return RETVAL_NOT_BZIP_DATA;
|
|
|
|
/* Fourth byte (ascii '1'-'9'), indicates block size in units of 100k of
|
|
uncompressed data. Allocate intermediate buffer for block. */
|
|
bd->dbufSize = 100000*(i-BZh0);
|
|
|
|
bd->dbuf = large_malloc(bd->dbufSize * sizeof(int));
|
|
if (!bd->dbuf)
|
|
return RETVAL_OUT_OF_MEMORY;
|
|
return RETVAL_OK;
|
|
}
|
|
|
|
/* Example usage: decompress src_fd to dst_fd. (Stops at end of bzip2 data,
|
|
not end of file.) */
|
|
STATIC int INIT bunzip2(unsigned char *buf, int len,
|
|
int(*fill)(void*, unsigned int),
|
|
int(*flush)(void*, unsigned int),
|
|
unsigned char *outbuf,
|
|
int *pos,
|
|
void(*error)(char *x))
|
|
{
|
|
struct bunzip_data *bd;
|
|
int i = -1;
|
|
unsigned char *inbuf;
|
|
|
|
if (flush)
|
|
outbuf = malloc(BZIP2_IOBUF_SIZE);
|
|
|
|
if (!outbuf) {
|
|
error("Could not allocate output buffer");
|
|
return RETVAL_OUT_OF_MEMORY;
|
|
}
|
|
if (buf)
|
|
inbuf = buf;
|
|
else
|
|
inbuf = malloc(BZIP2_IOBUF_SIZE);
|
|
if (!inbuf) {
|
|
error("Could not allocate input buffer");
|
|
i = RETVAL_OUT_OF_MEMORY;
|
|
goto exit_0;
|
|
}
|
|
i = start_bunzip(&bd, inbuf, len, fill);
|
|
if (!i) {
|
|
for (;;) {
|
|
i = read_bunzip(bd, outbuf, BZIP2_IOBUF_SIZE);
|
|
if (i <= 0)
|
|
break;
|
|
if (!flush)
|
|
outbuf += i;
|
|
else
|
|
if (i != flush(outbuf, i)) {
|
|
i = RETVAL_UNEXPECTED_OUTPUT_EOF;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
/* Check CRC and release memory */
|
|
if (i == RETVAL_LAST_BLOCK) {
|
|
if (bd->headerCRC != bd->totalCRC)
|
|
error("Data integrity error when decompressing.");
|
|
else
|
|
i = RETVAL_OK;
|
|
} else if (i == RETVAL_UNEXPECTED_OUTPUT_EOF) {
|
|
error("Compressed file ends unexpectedly");
|
|
}
|
|
if (!bd)
|
|
goto exit_1;
|
|
if (bd->dbuf)
|
|
large_free(bd->dbuf);
|
|
if (pos)
|
|
*pos = bd->inbufPos;
|
|
free(bd);
|
|
exit_1:
|
|
if (!buf)
|
|
free(inbuf);
|
|
exit_0:
|
|
if (flush)
|
|
free(outbuf);
|
|
return i;
|
|
}
|
|
|
|
#ifdef PREBOOT
|
|
STATIC int INIT decompress(unsigned char *buf, int len,
|
|
int(*fill)(void*, unsigned int),
|
|
int(*flush)(void*, unsigned int),
|
|
unsigned char *outbuf,
|
|
int *pos,
|
|
void(*error)(char *x))
|
|
{
|
|
return bunzip2(buf, len - 4, fill, flush, outbuf, pos, error);
|
|
}
|
|
#endif
|