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+/* vi: set sw = 4 ts = 4: */
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+/* Small bzip2 deflate implementation, by Rob Landley (rob@landley.net).
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+
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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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+
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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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+/*
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+ Size and speed optimizations by Manuel Novoa III (mjn3@codepoet.org).
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+
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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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+
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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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+
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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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+
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+ In memory of Toni W. Hagan
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+
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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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+
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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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+
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+ http://www.hospiceacadiana.com/
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+
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+ Manuel
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+ */
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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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+
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+
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+#ifndef STATIC
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+#include <linux/decompress/bunzip2.h>
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+#endif /* !STATIC */
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+
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+#include <linux/decompress/mm.h>
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+
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+#ifndef INT_MAX
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+#define INT_MAX 0x7fffffff
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+#endif
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+
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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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+
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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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+
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+/* Other housekeeping constants */
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+#define BZIP2_IOBUF_SIZE 4096
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+
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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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+
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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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+};
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+
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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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+
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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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+
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+ return bits;
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+}
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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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+
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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,
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+ byteCount[256];
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+ unsigned char uc, symToByte[256], mtfSymbol[256], *selectors;
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+ unsigned int *dbuf, origPtr;
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+
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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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+
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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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+
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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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+
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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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+
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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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+
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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[]. Concurently, 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. */
|
|
|
|
+ limit[maxLen] = pp+temp[maxLen]-1;
|
|
|
|
+ base[minLen] = 0;
|
|
|
|
+ }
|
|
|
|
+ /* We've finished reading and digesting the block header. Now
|
|
|
|
+ read this block's Huffman coded symbols from the file and
|
|
|
|
+ undo the Huffman coding and run length encoding, saving the
|
|
|
|
+ result into dbuf[dbufCount++] = uc */
|
|
|
|
+
|
|
|
|
+ /* Initialize symbol occurrence counters and symbol Move To
|
|
|
|
+ * Front table */
|
|
|
|
+ for (i = 0; i < 256; i++) {
|
|
|
|
+ byteCount[i] = 0;
|
|
|
|
+ mtfSymbol[i] = (unsigned char)i;
|
|
|
|
+ }
|
|
|
|
+ /* Loop through compressed symbols. */
|
|
|
|
+ runPos = dbufCount = symCount = selector = 0;
|
|
|
|
+ for (;;) {
|
|
|
|
+ /* Determine which Huffman coding group to use. */
|
|
|
|
+ if (!(symCount--)) {
|
|
|
|
+ symCount = GROUP_SIZE-1;
|
|
|
|
+ if (selector >= nSelectors)
|
|
|
|
+ return RETVAL_DATA_ERROR;
|
|
|
|
+ hufGroup = bd->groups+selectors[selector++];
|
|
|
|
+ base = hufGroup->base-1;
|
|
|
|
+ limit = hufGroup->limit-1;
|
|
|
|
+ }
|
|
|
|
+ /* Read next Huffman-coded symbol. */
|
|
|
|
+ /* Note: It is far cheaper to read maxLen bits and
|
|
|
|
+ back up than it is to read minLen bits and then an
|
|
|
|
+ additional bit at a time, testing as we go.
|
|
|
|
+ Because there is a trailing last block (with file
|
|
|
|
+ CRC), there is no danger of the overread causing an
|
|
|
|
+ unexpected EOF for a valid compressed file. As a
|
|
|
|
+ further optimization, we do the read inline
|
|
|
|
+ (falling back to a call to get_bits if the buffer
|
|
|
|
+ runs dry). The following (up to got_huff_bits:) is
|
|
|
|
+ equivalent to j = get_bits(bd, hufGroup->maxLen);
|
|
|
|
+ */
|
|
|
|
+ while (bd->inbufBitCount < hufGroup->maxLen) {
|
|
|
|
+ if (bd->inbufPos == bd->inbufCount) {
|
|
|
|
+ j = get_bits(bd, hufGroup->maxLen);
|
|
|
|
+ goto got_huff_bits;
|
|
|
|
+ }
|
|
|
|
+ bd->inbufBits =
|
|
|
|
+ (bd->inbufBits << 8)|bd->inbuf[bd->inbufPos++];
|
|
|
|
+ bd->inbufBitCount += 8;
|
|
|
|
+ };
|
|
|
|
+ bd->inbufBitCount -= hufGroup->maxLen;
|
|
|
|
+ j = (bd->inbufBits >> bd->inbufBitCount)&
|
|
|
|
+ ((1 << hufGroup->maxLen)-1);
|
|
|
|
+got_huff_bits:
|
|
|
|
+ /* Figure how how many bits are in next symbol and
|
|
|
|
+ * unget extras */
|
|
|
|
+ i = hufGroup->minLen;
|
|
|
|
+ while (j > limit[i])
|
|
|
|
+ ++i;
|
|
|
|
+ bd->inbufBitCount += (hufGroup->maxLen - i);
|
|
|
|
+ /* Huffman decode value to get nextSym (with bounds checking) */
|
|
|
|
+ if ((i > hufGroup->maxLen)
|
|
|
|
+ || (((unsigned)(j = (j>>(hufGroup->maxLen-i))-base[i]))
|
|
|
|
+ >= MAX_SYMBOLS))
|
|
|
|
+ return RETVAL_DATA_ERROR;
|
|
|
|
+ nextSym = hufGroup->permute[j];
|
|
|
|
+ /* We have now decoded the symbol, which indicates
|
|
|
|
+ either a new literal byte, or a repeated run of the
|
|
|
|
+ most recent literal byte. First, check if nextSym
|
|
|
|
+ indicates a repeated run, and if so loop collecting
|
|
|
|
+ how many times to repeat the last literal. */
|
|
|
|
+ if (((unsigned)nextSym) <= SYMBOL_RUNB) { /* RUNA or RUNB */
|
|
|
|
+ /* If this is the start of a new run, zero out
|
|
|
|
+ * counter */
|
|
|
|
+ if (!runPos) {
|
|
|
|
+ runPos = 1;
|
|
|
|
+ t = 0;
|
|
|
|
+ }
|
|
|
|
+ /* Neat trick that saves 1 symbol: instead of
|
|
|
|
+ or-ing 0 or 1 at each bit position, add 1
|
|
|
|
+ or 2 instead. For example, 1011 is 1 << 0
|
|
|
|
+ + 1 << 1 + 2 << 2. 1010 is 2 << 0 + 2 << 1
|
|
|
|
+ + 1 << 2. You can make any bit pattern
|
|
|
|
+ that way using 1 less symbol than the basic
|
|
|
|
+ or 0/1 method (except all bits 0, which
|
|
|
|
+ would use no symbols, but a run of length 0
|
|
|
|
+ doesn't mean anything in this context).
|
|
|
|
+ Thus space is saved. */
|
|
|
|
+ t += (runPos << nextSym);
|
|
|
|
+ /* +runPos if RUNA; +2*runPos if RUNB */
|
|
|
|
+
|
|
|
|
+ runPos <<= 1;
|
|
|
|
+ continue;
|
|
|
|
+ }
|
|
|
|
+ /* When we hit the first non-run symbol after a run,
|
|
|
|
+ we now know how many times to repeat the last
|
|
|
|
+ literal, so append that many copies to our buffer
|
|
|
|
+ of decoded symbols (dbuf) now. (The last literal
|
|
|
|
+ used is the one at the head of the mtfSymbol
|
|
|
|
+ array.) */
|
|
|
|
+ if (runPos) {
|
|
|
|
+ runPos = 0;
|
|
|
|
+ if (dbufCount+t >= dbufSize)
|
|
|
|
+ return RETVAL_DATA_ERROR;
|
|
|
|
+
|
|
|
|
+ uc = symToByte[mtfSymbol[0]];
|
|
|
|
+ byteCount[uc] += t;
|
|
|
|
+ while (t--)
|
|
|
|
+ dbuf[dbufCount++] = uc;
|
|
|
|
+ }
|
|
|
|
+ /* Is this the terminating symbol? */
|
|
|
|
+ if (nextSym > symTotal)
|
|
|
|
+ break;
|
|
|
|
+ /* At this point, nextSym indicates a new literal
|
|
|
|
+ character. Subtract one to get the position in the
|
|
|
|
+ MTF array at which this literal is currently to be
|
|
|
|
+ found. (Note that the result can't be -1 or 0,
|
|
|
|
+ because 0 and 1 are RUNA and RUNB. But another
|
|
|
|
+ instance of the first symbol in the mtf array,
|
|
|
|
+ position 0, would have been handled as part of a
|
|
|
|
+ run above. Therefore 1 unused mtf position minus 2
|
|
|
|
+ non-literal nextSym values equals -1.) */
|
|
|
|
+ if (dbufCount >= dbufSize)
|
|
|
|
+ return RETVAL_DATA_ERROR;
|
|
|
|
+ i = nextSym - 1;
|
|
|
|
+ uc = mtfSymbol[i];
|
|
|
|
+ /* Adjust the MTF array. Since we typically expect to
|
|
|
|
+ *move only a small number of symbols, and are bound
|
|
|
|
+ *by 256 in any case, using memmove here would
|
|
|
|
+ *typically be bigger and slower due to function call
|
|
|
|
+ *overhead and other assorted setup costs. */
|
|
|
|
+ do {
|
|
|
|
+ mtfSymbol[i] = mtfSymbol[i-1];
|
|
|
|
+ } while (--i);
|
|
|
|
+ mtfSymbol[0] = uc;
|
|
|
|
+ uc = symToByte[uc];
|
|
|
|
+ /* We have our literal byte. Save it into dbuf. */
|
|
|
|
+ byteCount[uc]++;
|
|
|
|
+ dbuf[dbufCount++] = (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);
|
|
|
|
+ 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));
|
|
|
|
+ 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_fn)(char *x))
|
|
|
|
+{
|
|
|
|
+ struct bunzip_data *bd;
|
|
|
|
+ int i = -1;
|
|
|
|
+ unsigned char *inbuf;
|
|
|
|
+
|
|
|
|
+ set_error_fn(error_fn);
|
|
|
|
+ if (flush)
|
|
|
|
+ outbuf = malloc(BZIP2_IOBUF_SIZE);
|
|
|
|
+ else
|
|
|
|
+ len -= 4; /* Uncompressed size hack active in pre-boot
|
|
|
|
+ environment */
|
|
|
|
+ if (!outbuf) {
|
|
|
|
+ error("Could not allocate output bufer");
|
|
|
|
+ return -1;
|
|
|
|
+ }
|
|
|
|
+ if (buf)
|
|
|
|
+ inbuf = buf;
|
|
|
|
+ else
|
|
|
|
+ inbuf = malloc(BZIP2_IOBUF_SIZE);
|
|
|
|
+ if (!inbuf) {
|
|
|
|
+ error("Could not allocate input bufer");
|
|
|
|
+ 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->dbuf)
|
|
|
|
+ large_free(bd->dbuf);
|
|
|
|
+ if (pos)
|
|
|
|
+ *pos = bd->inbufPos;
|
|
|
|
+ free(bd);
|
|
|
|
+ if (!buf)
|
|
|
|
+ free(inbuf);
|
|
|
|
+exit_0:
|
|
|
|
+ if (flush)
|
|
|
|
+ free(outbuf);
|
|
|
|
+ return i;
|
|
|
|
+}
|
|
|
|
+
|
|
|
|
+#define decompress bunzip2
|