Merge branch 'x86/core' into tracing/textedit

Conflicts:
	arch/x86/Kconfig
	block/blktrace.c
	kernel/irq/handle.c

Semantic conflict:
	kernel/trace/blktrace.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 735 insertions, 0 deletions

diff --git a/lib/decompress_bunzip2.c b/lib/decompress_bunzip2.c
new file mode 100644
index 000000000000..5d3ddb5fcfd9
--- /dev/null
+++ b/lib/decompress_bunzip2.c
@@ -0,0 +1,735 @@
+/* vi: set sw = 4 ts = 4: */
+/*      Small bzip2 deflate implementation, by Rob Landley (rob@landley.net).
+
+        Based on bzip2 decompression code by Julian R Seward (jseward@acm.org),
+        which also acknowledges contributions by Mike Burrows, David Wheeler,
+        Peter Fenwick, Alistair Moffat, Radford Neal, Ian H. Witten,
+        Robert Sedgewick, and Jon L. Bentley.
+
+        This code is licensed under the LGPLv2:
+                LGPL (http://www.gnu.org/copyleft/lgpl.html
+*/
+
+/*
+        Size and speed optimizations by Manuel Novoa III  (mjn3@codepoet.org).
+
+        More efficient reading of Huffman codes, a streamlined read_bunzip()
+        function, and various other tweaks.  In (limited) tests, approximately
+        20% faster than bzcat on x86 and about 10% faster on arm.
+
+        Note that about 2/3 of the time is spent in read_unzip() reversing
+        the Burrows-Wheeler transformation.  Much of that time is delay
+        resulting from cache misses.
+
+        I would ask that anyone benefiting from this work, especially those
+        using it in commercial products, consider making a donation to my local
+        non-profit hospice organization in the name of the woman I loved, who
+        passed away Feb. 12, 2003.
+
+                In memory of Toni W. Hagan
+
+                Hospice of Acadiana, Inc.
+                2600 Johnston St., Suite 200
+                Lafayette, LA 70503-3240
+
+                Phone (337) 232-1234 or 1-800-738-2226
+                Fax   (337) 232-1297
+
+                http://www.hospiceacadiana.com/
+
+        Manuel
+ */
+
+/*
+        Made it fit for running in Linux Kernel by Alain Knaff (alain@knaff.lu)
+*/
+
+
+#ifndef STATIC
+#include <linux/decompress/bunzip2.h>
+#endif /* !STATIC */
+
+#include <linux/decompress/mm.h>
+
+#ifndef INT_MAX
+#define INT_MAX 0x7fffffff
+#endif
+
+/* Constants for Huffman coding */
+#define MAX_GROUPS              6
+#define GROUP_SIZE              50      /* 64 would have been more efficient */
+#define MAX_HUFCODE_BITS        20      /* Longest Huffman code allowed */
+#define MAX_SYMBOLS             258     /* 256 literals + RUNA + RUNB */
+#define SYMBOL_RUNA             0
+#define SYMBOL_RUNB             1
+
+/* Status return values */
+#define RETVAL_OK                       0
+#define RETVAL_LAST_BLOCK               (-1)
+#define RETVAL_NOT_BZIP_DATA            (-2)
+#define RETVAL_UNEXPECTED_INPUT_EOF     (-3)
+#define RETVAL_UNEXPECTED_OUTPUT_EOF    (-4)
+#define RETVAL_DATA_ERROR               (-5)
+#define RETVAL_OUT_OF_MEMORY            (-6)
+#define RETVAL_OBSOLETE_INPUT           (-7)
+
+/* Other housekeeping constants */
+#define BZIP2_IOBUF_SIZE                4096
+
+/* This is what we know about each Huffman coding group */
+struct group_data {
+        /* We have an extra slot at the end of limit[] for a sentinal value. */
+        int limit[MAX_HUFCODE_BITS+1];
+        int base[MAX_HUFCODE_BITS];
+        int permute[MAX_SYMBOLS];
+        int minLen, maxLen;
+};
+
+/* Structure holding all the housekeeping data, including IO buffers and
+   memory that persists between calls to bunzip */
+struct bunzip_data {
+        /* State for interrupting output loop */
+        int writeCopies, writePos, writeRunCountdown, writeCount, writeCurrent;
+        /* I/O tracking data (file handles, buffers, positions, etc.) */
+        int (*fill)(void*, unsigned int);
+        int inbufCount, inbufPos /*, outbufPos*/;
+        unsigned char *inbuf /*,*outbuf*/;
+        unsigned int inbufBitCount, inbufBits;
+        /* The CRC values stored in the block header and calculated from the
+        data */
+        unsigned int crc32Table[256], headerCRC, totalCRC, writeCRC;
+        /* Intermediate buffer and its size (in bytes) */
+        unsigned int *dbuf, dbufSize;
+        /* These things are a bit too big to go on the stack */
+        unsigned char selectors[32768];         /* nSelectors = 15 bits */
+        struct group_data groups[MAX_GROUPS];   /* Huffman coding tables */
+        int io_error;                   /* non-zero if we have IO error */
+};
+
+
+/* Return the next nnn bits of input.  All reads from the compressed input
+   are done through this function.  All reads are big endian */
+static unsigned int INIT get_bits(struct bunzip_data *bd, char bits_wanted)
+{
+        unsigned int bits = 0;
+
+        /* If we need to get more data from the byte buffer, do so.
+           (Loop getting one byte at a time to enforce endianness and avoid
+           unaligned access.) */
+        while (bd->inbufBitCount < bits_wanted) {
+                /* If we need to read more data from file into byte buffer, do
+                   so */
+                if (bd->inbufPos == bd->inbufCount) {
+                        if (bd->io_error)
+                                return 0;
+                        bd->inbufCount = bd->fill(bd->inbuf, BZIP2_IOBUF_SIZE);
+                        if (bd->inbufCount <= 0) {
+                                bd->io_error = RETVAL_UNEXPECTED_INPUT_EOF;
+                                return 0;
+                        }
+                        bd->inbufPos = 0;
+                }
+                /* Avoid 32-bit overflow (dump bit buffer to top of output) */
+                if (bd->inbufBitCount >= 24) {
+                        bits = bd->inbufBits&((1 << bd->inbufBitCount)-1);
+                        bits_wanted -= bd->inbufBitCount;
+                        bits <<= bits_wanted;
+                        bd->inbufBitCount = 0;
+                }
+                /* Grab next 8 bits of input from buffer. */
+                bd->inbufBits = (bd->inbufBits << 8)|bd->inbuf[bd->inbufPos++];
+                bd->inbufBitCount += 8;
+        }
+        /* Calculate result */
+        bd->inbufBitCount -= bits_wanted;
+        bits |= (bd->inbufBits >> bd->inbufBitCount)&((1 << bits_wanted)-1);
+
+        return bits;
+}
+
+/* Unpacks the next block and sets up for the inverse burrows-wheeler step. */
+
+static int INIT get_next_block(struct bunzip_data *bd)
+{
+        struct group_data *hufGroup = NULL;
+        int *base = NULL;
+        int *limit = NULL;
+        int dbufCount, nextSym, dbufSize, groupCount, selector,
+                i, j, k, t, runPos, symCount, symTotal, nSelectors,
+                byteCount[256];
+        unsigned char uc, symToByte[256], mtfSymbol[256], *selectors;
+        unsigned int *dbuf, origPtr;
+
+        dbuf = bd->dbuf;
+        dbufSize = bd->dbufSize;
+        selectors = bd->selectors;
+
+        /* Read in header signature and CRC, then validate signature.
+           (last block signature means CRC is for whole file, return now) */
+        i = get_bits(bd, 24);
+        j = get_bits(bd, 24);
+        bd->headerCRC = get_bits(bd, 32);
+        if ((i == 0x177245) && (j == 0x385090))
+                return RETVAL_LAST_BLOCK;
+        if ((i != 0x314159) || (j != 0x265359))
+                return RETVAL_NOT_BZIP_DATA;
+        /* We can add support for blockRandomised if anybody complains.
+           There was some code for this in busybox 1.0.0-pre3, but nobody ever
+           noticed that it didn't actually work. */
+        if (get_bits(bd, 1))
+                return RETVAL_OBSOLETE_INPUT;
+        origPtr = get_bits(bd, 24);
+        if (origPtr > dbufSize)
+                return RETVAL_DATA_ERROR;
+        /* mapping table: if some byte values are never used (encoding things
+           like ascii text), the compression code removes the gaps to have fewer
+           symbols to deal with, and writes a sparse bitfield indicating which
+           values were present.  We make a translation table to convert the
+           symbols back to the corresponding bytes. */
+        t = get_bits(bd, 16);
+        symTotal = 0;
+        for (i = 0; i < 16; i++) {
+                if (t&(1 << (15-i))) {
+                        k = get_bits(bd, 16);
+                        for (j = 0; j < 16; j++)
+                                if (k&(1 << (15-j)))
+                                        symToByte[symTotal++] = (16*i)+j;
+                }
+        }
+        /* How many different Huffman coding groups does this block use? */
+        groupCount = get_bits(bd, 3);
+        if (groupCount < 2 || groupCount > MAX_GROUPS)
+                return RETVAL_DATA_ERROR;
+        /* nSelectors: Every GROUP_SIZE many symbols we select a new
+           Huffman coding group.  Read in the group selector list,
+           which is stored as MTF encoded bit runs.  (MTF = Move To
+           Front, as each value is used it's moved to the start of the
+           list.) */
+        nSelectors = get_bits(bd, 15);
+        if (!nSelectors)
+                return RETVAL_DATA_ERROR;
+        for (i = 0; i < groupCount; i++)
+                mtfSymbol[i] = i;
+        for (i = 0; i < nSelectors; i++) {
+                /* Get next value */
+                for (j = 0; get_bits(bd, 1); j++)
+                        if (j >= groupCount)
+                                return RETVAL_DATA_ERROR;
+                /* Decode MTF to get the next selector */
+                uc = mtfSymbol[j];
+                for (; j; j--)
+                        mtfSymbol[j] = mtfSymbol[j-1];
+                mtfSymbol[0] = selectors[i] = uc;
+        }
+        /* Read the Huffman coding tables for each group, which code
+           for symTotal literal symbols, plus two run symbols (RUNA,
+           RUNB) */
+        symCount = symTotal+2;
+        for (j = 0; j < groupCount; j++) {
+                unsigned char length[MAX_SYMBOLS], temp[MAX_HUFCODE_BITS+1];
+                int     minLen, maxLen, pp;
+                /* Read Huffman code lengths for each symbol.  They're
+                   stored in a way similar to mtf; record a starting
+                   value for the first symbol, and an offset from the
+                   previous value for everys symbol after that.
+                   (Subtracting 1 before the loop and then adding it
+                   back at the end is an optimization that makes the
+                   test inside the loop simpler: symbol length 0
+                   becomes negative, so an unsigned inequality catches
+                   it.) */
+                t = get_bits(bd, 5)-1;
+                for (i = 0; i < symCount; i++) {
+                        for (;;) {
+                                if (((unsigned)t) > (MAX_HUFCODE_BITS-1))
+                                        return RETVAL_DATA_ERROR;
+
+                                /* If first bit is 0, stop.  Else
+                                   second bit indicates whether to
+                                   increment or decrement the value.
+                                   Optimization: grab 2 bits and unget
+                                   the second if the first was 0. */
+
+                                k = get_bits(bd, 2);
+                                if (k < 2) {
+                                        bd->inbufBitCount++;
+                                        break;
+                                }
+                                /* Add one if second bit 1, else
+                                 * subtract 1.  Avoids if/else */
+                                t += (((k+1)&2)-1);
+                        }
+                        /* Correct for the initial -1, to get the
+                         * final symbol length */
+                        length[i] = t+1;
+                }
+                /* Find largest and smallest lengths in this group */
+                minLen = maxLen = length[0];
+
+                for (i = 1; i < symCount; i++) {
+                        if (length[i] > maxLen)
+                                maxLen = length[i];
+                        else if (length[i] < minLen)
+                                minLen = length[i];
+                }
+
+                /* Calculate permute[], base[], and limit[] tables from
+                 * length[].
+                 *
+                 * permute[] is the lookup table for converting
+                 * Huffman coded symbols into decoded symbols.  base[]
+                 * is the amount to subtract from the value of a
+                 * Huffman symbol of a given length when using
+                 * permute[].
+                 *
+                 * limit[] indicates the largest numerical value a
+                 * symbol with a given number of bits can have.  This
+                 * is how the Huffman codes can vary in length: each
+                 * code with a value > limit[length] needs another
+                 * bit.
+                 */
+                hufGroup = bd->groups+j;
+                hufGroup->minLen = minLen;
+                hufGroup->maxLen = maxLen;
+                /* Note that minLen can't be smaller than 1, so we
+                   adjust the base and limit array pointers so we're
+                   not always wasting the first entry.  We do this
+                   again when using them (during symbol decoding).*/
+                base = hufGroup->base-1;
+                limit = hufGroup->limit-1;
+                /* Calculate permute[].  Concurently, initialize
+                 * temp[] and limit[]. */
+                pp = 0;
+                for (i = minLen; i <= maxLen; i++) {
+                        temp[i] = limit[i] = 0;
+                        for (t = 0; t < symCount; t++)
+                                if (length[t] == i)
+                                        hufGroup->permute[pp++] = t;
+                }
+                /* Count symbols coded for at each bit length */
+                for (i = 0; i < symCount; i++)
+                        temp[length[i]]++;
+                /* Calculate limit[] (the largest symbol-coding value
+                 *at each bit length, which is (previous limit <<
+                 *1)+symbols at this level), and base[] (number of
+                 *symbols to ignore at each bit length, which is limit
+                 *minus the cumulative count of symbols coded for
+                 *already). */
+                pp = t = 0;
+                for (i = minLen; i < maxLen; i++) {
+                        pp += temp[i];
+                        /* We read the largest possible symbol size
+                           and then unget bits after determining how
+                           many we need, and those extra bits could be
+                           set to anything.  (They're noise from
+                           future symbols.)  At each level we're
+                           really only interested in the first few
+                           bits, so here we set all the trailing
+                           to-be-ignored bits to 1 so they don't
+                           affect the value > limit[length]
+                           comparison. */
+                        limit[i] = (pp << (maxLen - i)) - 1;
+                        pp <<= 1;
+                        base[i+1] = pp-(t += temp[i]);
+                }
+                limit[maxLen+1] = INT_MAX; /* Sentinal value for
+                                            * 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