On Thu, 2009-11-05 at 14:24 +0000, Jan Beulich wrote:
> This matches functionality in the tools already supporting the same for
> DomU-s.
>
> Code taken from Linux 2.6.32-rc and adjusted as little as possible to
> be usable in Xen.
Looks good to me. The new files FOO.c are based on lib/decompress_FOO.c
from Linux? Might be worth a comment in at least the changelog to aid
the next person to come along who wants to resync them. (and why rename
them?)
> The question is whether, particularly for non-Linux Dom0-s, plain ELF
> images compressed by bzip2 or lzma should also be supported.
It should be fairly low cost to do so, so why not?
Is there a reason to treat gzip differently to bzip2/lzma? i.e. why not
route it through decompress.c as well? Perhaps that would involve
updating xen/common/inflate.c but that is already just a fork of what is
now in lib/decompress_inflate.c in Linux so it should be pretty trivial.
> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx>
>
> --- 2009-10-27.orig/xen/arch/x86/bzimage.c 2009-10-07 13:31:36.000000000
> +0200
> +++ 2009-10-27/xen/arch/x86/bzimage.c 2009-11-05 12:23:05.000000000 +0100
> @@ -4,6 +4,7 @@
> #include <xen/mm.h>
> #include <xen/string.h>
> #include <xen/types.h>
> +#include <xen/decompress.h>
> #include <asm/bzimage.h>
>
> #define HEAPORDER 3
> @@ -93,28 +94,38 @@ static __init void flush_window(void)
> outcnt = 0;
> }
>
> -static __init int gzip_length(char *image, unsigned long image_len)
> +static __init unsigned long output_length(char *image, unsigned long
> image_len)
> {
> return *(uint32_t *)&image[image_len - 4];
> }
>
> -static __init int perform_gunzip(char *output, char **_image_start,
> unsigned long *image_len)
> +static __init int gzip_check(char *image, unsigned long image_len)
> {
> - char *image = *_image_start;
> - int rc;
> - unsigned char magic0 = (unsigned char)image[0];
> - unsigned char magic1 = (unsigned char)image[1];
> + unsigned char magic0, magic1;
>
> - if ( magic0 != 0x1f || ( (magic1 != 0x8b) && (magic1 != 0x9e) ) )
> + if ( image_len < 2 )
> return 0;
>
> + magic0 = (unsigned char)image[0];
> + magic1 = (unsigned char)image[1];
> +
> + return (magic0 == 0x1f) && ((magic1 == 0x8b) || (magic1 == 0x9e));
> +}
> +
> +static __init int perform_gunzip(char *output, char *image, unsigned long
> image_len)
> +{
> + int rc;
> +
> + if ( !gzip_check(image, image_len) )
> + return 1;
> +
> window = (unsigned char *)output;
>
> free_mem_ptr = (unsigned long)alloc_xenheap_pages(HEAPORDER, 0);
> free_mem_end_ptr = free_mem_ptr + (PAGE_SIZE << HEAPORDER);
>
> inbuf = (unsigned char *)image;
> - insize = *image_len;
> + insize = image_len;
> inptr = 0;
>
> makecrc();
> @@ -125,8 +136,6 @@ static __init int perform_gunzip(char *
> }
> else
> {
> - *_image_start = (char *)window;
> - *image_len = gzip_length(image, *image_len);
> rc = 0;
> }
>
> @@ -203,9 +212,12 @@ int __init bzimage_headroom(char *image_
> img = image_start + (hdr->setup_sects+1) * 512;
> img += hdr->payload_offset;
>
> - headroom = gzip_length(img, hdr->payload_length);
> - headroom += headroom >> 12; /* Add 8 bytes for every 32K input block */
> - headroom += (32768 + 18); /* Add 32K + 18 bytes of extra headroom */
> + headroom = output_length(img, hdr->payload_length);
> + if (gzip_check(img, hdr->payload_length)) {
> + headroom += headroom >> 12; /* Add 8 bytes for every 32K input block
> */
> + headroom += (32768 + 18); /* Add 32K + 18 bytes of extra headroom */
> + } else
> + headroom += hdr->payload_length;
> headroom = (headroom + 4095) & ~4095;
>
> return headroom;
> @@ -215,6 +227,7 @@ int __init bzimage_parse(char *image_bas
> {
> struct setup_header *hdr = (struct setup_header *)(*image_start);
> int err = bzimage_check(hdr, *image_len);
> + unsigned long output_len;
>
> if (err < 1)
> return err;
> @@ -224,11 +237,18 @@ int __init bzimage_parse(char *image_bas
> *image_start += (hdr->setup_sects+1) * 512;
> *image_start += hdr->payload_offset;
> *image_len = hdr->payload_length;
> + output_len = output_length(*image_start, *image_len);
>
> - if ( (err = perform_gunzip(image_base, image_start, image_len)) < 0 )
> - return err;
> + if ( (err = perform_gunzip(image_base, *image_start, *image_len)) > 0 )
> + err = decompress(*image_start, *image_len, image_base);
> +
> + if ( !err )
> + {
> + *image_start = image_base;
> + *image_len = output_len;
> + }
>
> - return 0;
> + return err > 0 ? 0 : err;
> }
>
> /*
> --- 2009-10-27.orig/xen/common/Makefile 2009-05-27 13:54:07.000000000 +0200
> +++ 2009-10-27/xen/common/Makefile 2009-11-05 12:26:53.000000000 +0100
> @@ -35,6 +35,8 @@ obj-y += radix-tree.o
> obj-y += rbtree.o
> obj-y += lzo.o
>
> +obj-$(CONFIG_X86) += decompress.o bunzip2.o unlzma.o
> +
> obj-$(perfc) += perfc.o
> obj-$(crash_debug) += gdbstub.o
> obj-$(xenoprof) += xenoprof.o
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ 2009-10-27/xen/common/bunzip2.c 2009-11-05 12:44:51.000000000 +0100
> @@ -0,0 +1,726 @@
> +/* vi: set sw = 4 ts = 4: */
> +/* Small bzip2 deflate implementation, by Rob Landley (rob@xxxxxxxxxxx).
> +
> + Based on bzip2 decompression code by Julian R Seward
> (jseward@xxxxxxx),
> + 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@xxxxxxxxxxxx).
> +
> + 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@xxxxxxxx)
> +*/
> +
> +#include "decompress.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, unsigned 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, unsigned int len,
> + int(*fill)(void*, unsigned int),
> + int(*flush)(void*, unsigned int),
> + unsigned char *outbuf,
> + unsigned int *pos,
> + void(*error_fn)(const char *x))
> +{
> + struct bunzip_data *bd;
> + int i = -1;
> + unsigned char *inbuf;
> +
> + set_error_fn(error_fn);
> + if (flush)
> + outbuf = malloc(BZIP2_IOBUF_SIZE);
> +
> + 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;
> +}
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ 2009-10-27/xen/common/decompress.c 2009-11-05 12:27:10.000000000 +0100
> @@ -0,0 +1,27 @@
> +#include <xen/config.h>
> +#include <xen/init.h>
> +#include <xen/lib.h>
> +#include <xen/string.h>
> +#include <xen/decompress.h>
> +
> +static void __init error(const char *msg)
> +{
> + printk("%s\n", msg);
> +}
> +
> +int __init decompress(void *inbuf, unsigned int len, void *outbuf)
> +{
> +#if 0 /* Not needed here yet. */
> + if ( len >= 2 &&
> + (!memcmp(inbuf, "\037\213", 2) || !memcmp(inbuf, "\037\236", 2)) )
> + return gunzip(inbuf, len, NULL, NULL, outbuf, NULL, error);
> +#endif
> +
> + if ( len >= 3 && !memcmp(inbuf, "\x42\x5a\x68", 3) )
> + return bunzip2(inbuf, len, NULL, NULL, outbuf, NULL, error);
> +
> + if ( len >= 2 && !memcmp(inbuf, "\135\000", 2) )
> + return unlzma(inbuf, len, NULL, NULL, outbuf, NULL, error);
> +
> + return 1;
> +}
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ 2009-10-27/xen/common/decompress.h 2009-11-05 15:21:52.000000000 +0100
> @@ -0,0 +1,19 @@
> +#include <xen/config.h>
> +#include <xen/cache.h>
> +#include <xen/decompress.h>
> +#include <xen/init.h>
> +#include <xen/string.h>
> +#include <xen/types.h>
> +#include <xen/xmalloc.h>
> +
> +#define STATIC
> +#define INIT __init
> +
> +static void(*__initdata error)(const char *);
> +#define set_error_fn(x) error = x;
> +
> +#define malloc xmalloc_bytes
> +#define free xfree
> +
> +#define large_malloc xmalloc_bytes
> +#define large_free xfree
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ 2009-10-27/xen/common/unlzma.c 2009-11-05 12:45:37.000000000 +0100
> @@ -0,0 +1,647 @@
> +/* Lzma decompressor for Linux kernel. Shamelessly snarfed
> + * from busybox 1.1.1
> + *
> + * Linux kernel adaptation
> + * Copyright (C) 2006 Alain < alain@xxxxxxxx >
> + *
> + * Based on small lzma deflate implementation/Small range coder
> + * implementation for lzma.
> + * Copyright (C) 2006 Aurelien Jacobs < aurel@xxxxxxxxxx >
> + *
> + * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
> + * Copyright (C) 1999-2005 Igor Pavlov
> + *
> + * Copyrights of the parts, see headers below.
> + *
> + *
> + * This program is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with this library; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
> + */
> +
> +#include "decompress.h"
> +
> +#define MIN(a, b) (((a) < (b)) ? (a) : (b))
> +
> +static long long INIT read_int(unsigned char *ptr, int size)
> +{
> + int i;
> + long long ret = 0;
> +
> + for (i = 0; i < size; i++)
> + ret = (ret << 8) | ptr[size-i-1];
> + return ret;
> +}
> +
> +#define ENDIAN_CONVERT(x) \
> + x = (typeof(x))read_int((unsigned char *)&x, sizeof(x))
> +
> +
> +/* Small range coder implementation for lzma.
> + * Copyright (C) 2006 Aurelien Jacobs < aurel@xxxxxxxxxx >
> + *
> + * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
> + * Copyright (c) 1999-2005 Igor Pavlov
> + */
> +
> +#include <xen/compiler.h>
> +
> +#define LZMA_IOBUF_SIZE 0x10000
> +
> +struct rc {
> + int (*fill)(void*, unsigned int);
> + uint8_t *ptr;
> + uint8_t *buffer;
> + uint8_t *buffer_end;
> + int buffer_size;
> + uint32_t code;
> + uint32_t range;
> + uint32_t bound;
> +};
> +
> +
> +#define RC_TOP_BITS 24
> +#define RC_MOVE_BITS 5
> +#define RC_MODEL_TOTAL_BITS 11
> +
> +
> +static int nofill(void *buffer, unsigned int len)
> +{
> + return -1;
> +}
> +
> +/* Called twice: once at startup and once in rc_normalize() */
> +static void INIT rc_read(struct rc *rc)
> +{
> + rc->buffer_size = rc->fill((char *)rc->buffer, LZMA_IOBUF_SIZE);
> + if (rc->buffer_size <= 0)
> + error("unexpected EOF");
> + rc->ptr = rc->buffer;
> + rc->buffer_end = rc->buffer + rc->buffer_size;
> +}
> +
> +/* Called once */
> +static inline void INIT rc_init(struct rc *rc,
> + int (*fill)(void*, unsigned int),
> + unsigned char *buffer, int buffer_size)
> +{
> + if (fill)
> + rc->fill = fill;
> + else
> + rc->fill = nofill;
> + rc->buffer = (uint8_t *)buffer;
> + rc->buffer_size = buffer_size;
> + rc->buffer_end = rc->buffer + rc->buffer_size;
> + rc->ptr = rc->buffer;
> +
> + rc->code = 0;
> + rc->range = 0xFFFFFFFF;
> +}
> +
> +static inline void INIT rc_init_code(struct rc *rc)
> +{
> + int i;
> +
> + for (i = 0; i < 5; i++) {
> + if (rc->ptr >= rc->buffer_end)
> + rc_read(rc);
> + rc->code = (rc->code << 8) | *rc->ptr++;
> + }
> +}
> +
> +
> +/* Called once. TODO: bb_maybe_free() */
> +static inline void INIT rc_free(struct rc *rc)
> +{
> + free(rc->buffer);
> +}
> +
> +/* Called twice, but one callsite is in inline'd rc_is_bit_0_helper() */
> +static void INIT rc_do_normalize(struct rc *rc)
> +{
> + if (rc->ptr >= rc->buffer_end)
> + rc_read(rc);
> + rc->range <<= 8;
> + rc->code = (rc->code << 8) | *rc->ptr++;
> +}
> +static inline void INIT rc_normalize(struct rc *rc)
> +{
> + if (rc->range < (1 << RC_TOP_BITS))
> + rc_do_normalize(rc);
> +}
> +
> +/* Called 9 times */
> +/* Why rc_is_bit_0_helper exists?
> + *Because we want to always expose (rc->code < rc->bound) to optimizer
> + */
> +static inline uint32_t INIT rc_is_bit_0_helper(struct rc *rc, uint16_t *p)
> +{
> + rc_normalize(rc);
> + rc->bound = *p * (rc->range >> RC_MODEL_TOTAL_BITS);
> + return rc->bound;
> +}
> +static inline int INIT rc_is_bit_0(struct rc *rc, uint16_t *p)
> +{
> + uint32_t t = rc_is_bit_0_helper(rc, p);
> + return rc->code < t;
> +}
> +
> +/* Called ~10 times, but very small, thus inlined */
> +static inline void INIT rc_update_bit_0(struct rc *rc, uint16_t *p)
> +{
> + rc->range = rc->bound;
> + *p += ((1 << RC_MODEL_TOTAL_BITS) - *p) >> RC_MOVE_BITS;
> +}
> +static inline void rc_update_bit_1(struct rc *rc, uint16_t *p)
> +{
> + rc->range -= rc->bound;
> + rc->code -= rc->bound;
> + *p -= *p >> RC_MOVE_BITS;
> +}
> +
> +/* Called 4 times in unlzma loop */
> +static int INIT rc_get_bit(struct rc *rc, uint16_t *p, int *symbol)
> +{
> + if (rc_is_bit_0(rc, p)) {
> + rc_update_bit_0(rc, p);
> + *symbol *= 2;
> + return 0;
> + } else {
> + rc_update_bit_1(rc, p);
> + *symbol = *symbol * 2 + 1;
> + return 1;
> + }
> +}
> +
> +/* Called once */
> +static inline int INIT rc_direct_bit(struct rc *rc)
> +{
> + rc_normalize(rc);
> + rc->range >>= 1;
> + if (rc->code >= rc->range) {
> + rc->code -= rc->range;
> + return 1;
> + }
> + return 0;
> +}
> +
> +/* Called twice */
> +static inline void INIT
> +rc_bit_tree_decode(struct rc *rc, uint16_t *p, int num_levels, int *symbol)
> +{
> + int i = num_levels;
> +
> + *symbol = 1;
> + while (i--)
> + rc_get_bit(rc, p + *symbol, symbol);
> + *symbol -= 1 << num_levels;
> +}
> +
> +
> +/*
> + * Small lzma deflate implementation.
> + * Copyright (C) 2006 Aurelien Jacobs < aurel@xxxxxxxxxx >
> + *
> + * Based on LzmaDecode.c from the LZMA SDK 4.22 (http://www.7-zip.org/)
> + * Copyright (C) 1999-2005 Igor Pavlov
> + */
> +
> +
> +struct lzma_header {
> + uint8_t pos;
> + uint32_t dict_size;
> + uint64_t dst_size;
> +} __attribute__ ((packed)) ;
> +
> +
> +#define LZMA_BASE_SIZE 1846
> +#define LZMA_LIT_SIZE 768
> +
> +#define LZMA_NUM_POS_BITS_MAX 4
> +
> +#define LZMA_LEN_NUM_LOW_BITS 3
> +#define LZMA_LEN_NUM_MID_BITS 3
> +#define LZMA_LEN_NUM_HIGH_BITS 8
> +
> +#define LZMA_LEN_CHOICE 0
> +#define LZMA_LEN_CHOICE_2 (LZMA_LEN_CHOICE + 1)
> +#define LZMA_LEN_LOW (LZMA_LEN_CHOICE_2 + 1)
> +#define LZMA_LEN_MID (LZMA_LEN_LOW \
> + + (1 << (LZMA_NUM_POS_BITS_MAX +
> LZMA_LEN_NUM_LOW_BITS)))
> +#define LZMA_LEN_HIGH (LZMA_LEN_MID \
> + +(1 << (LZMA_NUM_POS_BITS_MAX +
> LZMA_LEN_NUM_MID_BITS)))
> +#define LZMA_NUM_LEN_PROBS (LZMA_LEN_HIGH + (1 << LZMA_LEN_NUM_HIGH_BITS))
> +
> +#define LZMA_NUM_STATES 12
> +#define LZMA_NUM_LIT_STATES 7
> +
> +#define LZMA_START_POS_MODEL_INDEX 4
> +#define LZMA_END_POS_MODEL_INDEX 14
> +#define LZMA_NUM_FULL_DISTANCES (1 << (LZMA_END_POS_MODEL_INDEX >> 1))
> +
> +#define LZMA_NUM_POS_SLOT_BITS 6
> +#define LZMA_NUM_LEN_TO_POS_STATES 4
> +
> +#define LZMA_NUM_ALIGN_BITS 4
> +
> +#define LZMA_MATCH_MIN_LEN 2
> +
> +#define LZMA_IS_MATCH 0
> +#define LZMA_IS_REP (LZMA_IS_MATCH + (LZMA_NUM_STATES <<
> LZMA_NUM_POS_BITS_MAX))
> +#define LZMA_IS_REP_G0 (LZMA_IS_REP + LZMA_NUM_STATES)
> +#define LZMA_IS_REP_G1 (LZMA_IS_REP_G0 + LZMA_NUM_STATES)
> +#define LZMA_IS_REP_G2 (LZMA_IS_REP_G1 + LZMA_NUM_STATES)
> +#define LZMA_IS_REP_0_LONG (LZMA_IS_REP_G2 + LZMA_NUM_STATES)
> +#define LZMA_POS_SLOT (LZMA_IS_REP_0_LONG \
> + + (LZMA_NUM_STATES << LZMA_NUM_POS_BITS_MAX))
> +#define LZMA_SPEC_POS (LZMA_POS_SLOT \
> + +(LZMA_NUM_LEN_TO_POS_STATES <<
> LZMA_NUM_POS_SLOT_BITS))
> +#define LZMA_ALIGN (LZMA_SPEC_POS \
> + + LZMA_NUM_FULL_DISTANCES - LZMA_END_POS_MODEL_INDEX)
> +#define LZMA_LEN_CODER (LZMA_ALIGN + (1 << LZMA_NUM_ALIGN_BITS))
> +#define LZMA_REP_LEN_CODER (LZMA_LEN_CODER + LZMA_NUM_LEN_PROBS)
> +#define LZMA_LITERAL (LZMA_REP_LEN_CODER + LZMA_NUM_LEN_PROBS)
> +
> +
> +struct writer {
> + uint8_t *buffer;
> + uint8_t previous_byte;
> + size_t buffer_pos;
> + int bufsize;
> + size_t global_pos;
> + int(*flush)(void*, unsigned int);
> + struct lzma_header *header;
> +};
> +
> +struct cstate {
> + int state;
> + uint32_t rep0, rep1, rep2, rep3;
> +};
> +
> +static inline size_t INIT get_pos(struct writer *wr)
> +{
> + return
> + wr->global_pos + wr->buffer_pos;
> +}
> +
> +static inline uint8_t INIT peek_old_byte(struct writer *wr,
> + uint32_t offs)
> +{
> + if (!wr->flush) {
> + int32_t pos;
> + while (offs > wr->header->dict_size)
> + offs -= wr->header->dict_size;
> + pos = wr->buffer_pos - offs;
> + return wr->buffer[pos];
> + } else {
> + uint32_t pos = wr->buffer_pos - offs;
> + while (pos >= wr->header->dict_size)
> + pos += wr->header->dict_size;
> + return wr->buffer[pos];
> + }
> +
> +}
> +
> +static inline void INIT write_byte(struct writer *wr, uint8_t byte)
> +{
> + wr->buffer[wr->buffer_pos++] = wr->previous_byte = byte;
> + if (wr->flush && wr->buffer_pos == wr->header->dict_size) {
> + wr->buffer_pos = 0;
> + wr->global_pos += wr->header->dict_size;
> + wr->flush((char *)wr->buffer, wr->header->dict_size);
> + }
> +}
> +
> +
> +static inline void INIT copy_byte(struct writer *wr, uint32_t offs)
> +{
> + write_byte(wr, peek_old_byte(wr, offs));
> +}
> +
> +static inline void INIT copy_bytes(struct writer *wr,
> + uint32_t rep0, int len)
> +{
> + do {
> + copy_byte(wr, rep0);
> + len--;
> + } while (len != 0 && wr->buffer_pos < wr->header->dst_size);
> +}
> +
> +static inline void INIT process_bit0(struct writer *wr, struct rc *rc,
> + struct cstate *cst, uint16_t *p,
> + int pos_state, uint16_t *prob,
> + int lc, uint32_t literal_pos_mask) {
> + int mi = 1;
> + rc_update_bit_0(rc, prob);
> + prob = (p + LZMA_LITERAL +
> + (LZMA_LIT_SIZE
> + * (((get_pos(wr) & literal_pos_mask) << lc)
> + + (wr->previous_byte >> (8 - lc))))
> + );
> +
> + if (cst->state >= LZMA_NUM_LIT_STATES) {
> + int match_byte = peek_old_byte(wr, cst->rep0);
> + do {
> + int bit;
> + uint16_t *prob_lit;
> +
> + match_byte <<= 1;
> + bit = match_byte & 0x100;
> + prob_lit = prob + 0x100 + bit + mi;
> + if (rc_get_bit(rc, prob_lit, &mi)) {
> + if (!bit)
> + break;
> + } else {
> + if (bit)
> + break;
> + }
> + } while (mi < 0x100);
> + }
> + while (mi < 0x100) {
> + uint16_t *prob_lit = prob + mi;
> + rc_get_bit(rc, prob_lit, &mi);
> + }
> + write_byte(wr, mi);
> + if (cst->state < 4)
> + cst->state = 0;
> + else if (cst->state < 10)
> + cst->state -= 3;
> + else
> + cst->state -= 6;
> +}
> +
> +static inline void INIT process_bit1(struct writer *wr, struct rc *rc,
> + struct cstate *cst, uint16_t *p,
> + int pos_state, uint16_t *prob) {
> + int offset;
> + uint16_t *prob_len;
> + int num_bits;
> + int len;
> +
> + rc_update_bit_1(rc, prob);
> + prob = p + LZMA_IS_REP + cst->state;
> + if (rc_is_bit_0(rc, prob)) {
> + rc_update_bit_0(rc, prob);
> + cst->rep3 = cst->rep2;
> + cst->rep2 = cst->rep1;
> + cst->rep1 = cst->rep0;
> + cst->state = cst->state < LZMA_NUM_LIT_STATES ? 0 : 3;
> + prob = p + LZMA_LEN_CODER;
> + } else {
> + rc_update_bit_1(rc, prob);
> + prob = p + LZMA_IS_REP_G0 + cst->state;
> + if (rc_is_bit_0(rc, prob)) {
> + rc_update_bit_0(rc, prob);
> + prob = (p + LZMA_IS_REP_0_LONG
> + + (cst->state <<
> + LZMA_NUM_POS_BITS_MAX) +
> + pos_state);
> + if (rc_is_bit_0(rc, prob)) {
> + rc_update_bit_0(rc, prob);
> +
> + cst->state = cst->state < LZMA_NUM_LIT_STATES
> ?
> + 9 : 11;
> + copy_byte(wr, cst->rep0);
> + return;
> + } else {
> + rc_update_bit_1(rc, prob);
> + }
> + } else {
> + uint32_t distance;
> +
> + rc_update_bit_1(rc, prob);
> + prob = p + LZMA_IS_REP_G1 + cst->state;
> + if (rc_is_bit_0(rc, prob)) {
> + rc_update_bit_0(rc, prob);
> + distance = cst->rep1;
> + } else {
> + rc_update_bit_1(rc, prob);
> + prob = p + LZMA_IS_REP_G2 + cst->state;
> + if (rc_is_bit_0(rc, prob)) {
> + rc_update_bit_0(rc, prob);
> + distance = cst->rep2;
> + } else {
> + rc_update_bit_1(rc, prob);
> + distance = cst->rep3;
> + cst->rep3 = cst->rep2;
> + }
> + cst->rep2 = cst->rep1;
> + }
> + cst->rep1 = cst->rep0;
> + cst->rep0 = distance;
> + }
> + cst->state = cst->state < LZMA_NUM_LIT_STATES ? 8 : 11;
> + prob = p + LZMA_REP_LEN_CODER;
> + }
> +
> + prob_len = prob + LZMA_LEN_CHOICE;
> + if (rc_is_bit_0(rc, prob_len)) {
> + rc_update_bit_0(rc, prob_len);
> + prob_len = (prob + LZMA_LEN_LOW
> + + (pos_state <<
> + LZMA_LEN_NUM_LOW_BITS));
> + offset = 0;
> + num_bits = LZMA_LEN_NUM_LOW_BITS;
> + } else {
> + rc_update_bit_1(rc, prob_len);
> + prob_len = prob + LZMA_LEN_CHOICE_2;
> + if (rc_is_bit_0(rc, prob_len)) {
> + rc_update_bit_0(rc, prob_len);
> + prob_len = (prob + LZMA_LEN_MID
> + + (pos_state <<
> + LZMA_LEN_NUM_MID_BITS));
> + offset = 1 << LZMA_LEN_NUM_LOW_BITS;
> + num_bits = LZMA_LEN_NUM_MID_BITS;
> + } else {
> + rc_update_bit_1(rc, prob_len);
> + prob_len = prob + LZMA_LEN_HIGH;
> + offset = ((1 << LZMA_LEN_NUM_LOW_BITS)
> + + (1 << LZMA_LEN_NUM_MID_BITS));
> + num_bits = LZMA_LEN_NUM_HIGH_BITS;
> + }
> + }
> +
> + rc_bit_tree_decode(rc, prob_len, num_bits, &len);
> + len += offset;
> +
> + if (cst->state < 4) {
> + int pos_slot;
> +
> + cst->state += LZMA_NUM_LIT_STATES;
> + prob =
> + p + LZMA_POS_SLOT +
> + ((len <
> + LZMA_NUM_LEN_TO_POS_STATES ? len :
> + LZMA_NUM_LEN_TO_POS_STATES - 1)
> + << LZMA_NUM_POS_SLOT_BITS);
> + rc_bit_tree_decode(rc, prob,
> + LZMA_NUM_POS_SLOT_BITS,
> + &pos_slot);
> + if (pos_slot >= LZMA_START_POS_MODEL_INDEX) {
> + int i, mi;
> + num_bits = (pos_slot >> 1) - 1;
> + cst->rep0 = 2 | (pos_slot & 1);
> + if (pos_slot < LZMA_END_POS_MODEL_INDEX) {
> + cst->rep0 <<= num_bits;
> + prob = p + LZMA_SPEC_POS +
> + cst->rep0 - pos_slot - 1;
> + } else {
> + num_bits -= LZMA_NUM_ALIGN_BITS;
> + while (num_bits--)
> + cst->rep0 = (cst->rep0 << 1) |
> + rc_direct_bit(rc);
> + prob = p + LZMA_ALIGN;
> + cst->rep0 <<= LZMA_NUM_ALIGN_BITS;
> + num_bits = LZMA_NUM_ALIGN_BITS;
> + }
> + i = 1;
> + mi = 1;
> + while (num_bits--) {
> + if (rc_get_bit(rc, prob + mi, &mi))
> + cst->rep0 |= i;
> + i <<= 1;
> + }
> + } else
> + cst->rep0 = pos_slot;
> + if (++(cst->rep0) == 0)
> + return;
> + }
> +
> + len += LZMA_MATCH_MIN_LEN;
> +
> + copy_bytes(wr, cst->rep0, len);
> +}
> +
> +
> +
> +STATIC inline int INIT unlzma(unsigned char *buf, unsigned int in_len,
> + int(*fill)(void*, unsigned int),
> + int(*flush)(void*, unsigned int),
> + unsigned char *output,
> + unsigned int *posp,
> + void(*error_fn)(const char *x)
> + )
> +{
> + struct lzma_header header;
> + int lc, pb, lp;
> + uint32_t pos_state_mask;
> + uint32_t literal_pos_mask;
> + uint16_t *p;
> + int num_probs;
> + struct rc rc;
> + int i, mi;
> + struct writer wr;
> + struct cstate cst;
> + unsigned char *inbuf;
> + int ret = -1;
> +
> + set_error_fn(error_fn);
> +
> + if (buf)
> + inbuf = buf;
> + else
> + inbuf = malloc(LZMA_IOBUF_SIZE);
> + if (!inbuf) {
> + error("Could not allocate input bufer");
> + goto exit_0;
> + }
> +
> + cst.state = 0;
> + cst.rep0 = cst.rep1 = cst.rep2 = cst.rep3 = 1;
> +
> + wr.header = &header;
> + wr.flush = flush;
> + wr.global_pos = 0;
> + wr.previous_byte = 0;
> + wr.buffer_pos = 0;
> +
> + rc_init(&rc, fill, inbuf, in_len);
> +
> + for (i = 0; i < sizeof(header); i++) {
> + if (rc.ptr >= rc.buffer_end)
> + rc_read(&rc);
> + ((unsigned char *)&header)[i] = *rc.ptr++;
> + }
> +
> + if (header.pos >= (9 * 5 * 5))
> + error("bad header");
> +
> + mi = 0;
> + lc = header.pos;
> + while (lc >= 9) {
> + mi++;
> + lc -= 9;
> + }
> + pb = 0;
> + lp = mi;
> + while (lp >= 5) {
> + pb++;
> + lp -= 5;
> + }
> + pos_state_mask = (1 << pb) - 1;
> + literal_pos_mask = (1 << lp) - 1;
> +
> + ENDIAN_CONVERT(header.dict_size);
> + ENDIAN_CONVERT(header.dst_size);
> +
> + if (header.dict_size == 0)
> + header.dict_size = 1;
> +
> + if (output)
> + wr.buffer = output;
> + else {
> + wr.bufsize = MIN(header.dst_size, header.dict_size);
> + wr.buffer = large_malloc(wr.bufsize);
> + }
> + if (wr.buffer == NULL)
> + goto exit_1;
> +
> + num_probs = LZMA_BASE_SIZE + (LZMA_LIT_SIZE << (lc + lp));
> + p = (uint16_t *) large_malloc(num_probs * sizeof(*p));
> + if (p == 0)
> + goto exit_2;
> + num_probs = LZMA_LITERAL + (LZMA_LIT_SIZE << (lc + lp));
> + for (i = 0; i < num_probs; i++)
> + p[i] = (1 << RC_MODEL_TOTAL_BITS) >> 1;
> +
> + rc_init_code(&rc);
> +
> + while (get_pos(&wr) < header.dst_size) {
> + int pos_state = get_pos(&wr) & pos_state_mask;
> + uint16_t *prob = p + LZMA_IS_MATCH +
> + (cst.state << LZMA_NUM_POS_BITS_MAX) + pos_state;
> + if (rc_is_bit_0(&rc, prob))
> + process_bit0(&wr, &rc, &cst, p, pos_state, prob,
> + lc, literal_pos_mask);
> + else {
> + process_bit1(&wr, &rc, &cst, p, pos_state, prob);
> + if (cst.rep0 == 0)
> + break;
> + }
> + }
> +
> + if (posp)
> + *posp = rc.ptr-rc.buffer;
> + if (wr.flush)
> + wr.flush(wr.buffer, wr.buffer_pos);
> + ret = 0;
> + large_free(p);
> +exit_2:
> + if (!output)
> + large_free(wr.buffer);
> +exit_1:
> + if (!buf)
> + free(inbuf);
> +exit_0:
> + return ret;
> +}
> --- /dev/null 1970-01-01 00:00:00.000000000 +0000
> +++ 2009-10-27/xen/include/xen/decompress.h 2009-11-05 12:27:44.000000000
> +0100
> @@ -0,0 +1,38 @@
> +#ifndef __XEN_GENERIC_H
> +#define __XEN_GENERIC_H
> +
> +typedef int decompress_fn(unsigned char *inbuf, unsigned int len,
> + int (*fill)(void*, unsigned int),
> + int (*flush)(void*, unsigned int),
> + unsigned char *outbuf, unsigned int *posp,
> + void (*error)(const char *x));
> +
> +/* inbuf - input buffer
> + * len - len of pre-read data in inbuf
> + * fill - function to fill inbuf when empty
> + * flush - function to write out outbuf
> + * outbuf - output buffer
> + * posp - if non-null, input position (number of bytes read) will be
> + * returned here
> + * error - error reporting function
> + *
> + * If len != 0, inbuf should contain all the necessary input data, and fill
> + * should be NULL
> + * If len = 0, inbuf can be NULL, in which case the decompressor will
> allocate
> + * the input buffer. If inbuf != NULL it must be at least XXX_IOBUF_SIZE
> bytes.
> + * fill will be called (repeatedly...) to read data, at most XXX_IOBUF_SIZE
> + * bytes should be read per call. Replace XXX with the appropriate
> decompressor
> + * name, i.e. LZMA_IOBUF_SIZE.
> + *
> + * If flush = NULL, outbuf must be large enough to buffer all the expected
> + * output. If flush != NULL, the output buffer will be allocated by the
> + * decompressor (outbuf = NULL), and the flush function will be called to
> + * flush the output buffer at the appropriate time (decompressor and stream
> + * dependent).
> + */
> +
> +decompress_fn bunzip2, unlzma;
> +
> +int decompress(void *inbuf, unsigned int len, void *outbuf);
> +
> +#endif
>
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