source: MondoRescue/branches/3.3/mindi-busybox/archival/libarchive/decompress_unxz.c@ 3884

/*
 * This file uses XZ Embedded library code which is written
 * by Lasse Collin <lasse.collin@tukaani.org>
 * and Igor Pavlov <http://7-zip.org/>
 *
 * See README file in unxz/ directory for more information.
 *
 * This file is:
 * Copyright (C) 2010 Denys Vlasenko <vda.linux@googlemail.com>
 * Licensed under GPLv2, see file LICENSE in this source tree.
 */
#include "libbb.h"
#include "bb_archive.h"

#define XZ_FUNC FAST_FUNC
#define XZ_EXTERN static

#define XZ_DEC_DYNALLOC

/* Skip check (rather than fail) of unsupported hash functions */
#define XZ_DEC_ANY_CHECK  1

/* We use our own crc32 function */
#define XZ_INTERNAL_CRC32 0
static uint32_t xz_crc32(const uint8_t *buf, size_t size, uint32_t crc)
{
    return ~crc32_block_endian0(~crc, buf, size, global_crc32_table);
}

/* We use arch-optimized unaligned accessors */
#define get_unaligned_le32(buf) ({ uint32_t v; move_from_unaligned32(v, buf); SWAP_LE32(v); })
#define get_unaligned_be32(buf) ({ uint32_t v; move_from_unaligned32(v, buf); SWAP_BE32(v); })
#define put_unaligned_le32(val, buf) move_to_unaligned32(buf, SWAP_LE32(val))
#define put_unaligned_be32(val, buf) move_to_unaligned32(buf, SWAP_BE32(val))

#include "unxz/xz_dec_bcj.c"
#include "unxz/xz_dec_lzma2.c"
#include "unxz/xz_dec_stream.c"

IF_DESKTOP(long long) int FAST_FUNC
unpack_xz_stream(transformer_state_t *xstate)
{
    enum xz_ret xz_result;
    struct xz_buf iobuf;
    struct xz_dec *state;
    unsigned char *membuf;
    IF_DESKTOP(long long) int total = 0;

    if (!global_crc32_table)
        global_crc32_table = crc32_filltable(NULL, /*endian:*/ 0);

    memset(&iobuf, 0, sizeof(iobuf));
    membuf = xmalloc(2 * BUFSIZ);
    iobuf.in = membuf;
    iobuf.out = membuf + BUFSIZ;
    iobuf.out_size = BUFSIZ;

    if (!xstate || xstate->signature_skipped) {
        /* Preload XZ file signature */
        strcpy((char*)membuf, HEADER_MAGIC);
        iobuf.in_size = HEADER_MAGIC_SIZE;
    } /* else: let xz code read & check it */

    /* Limit memory usage to about 64 MiB. */
    state = xz_dec_init(XZ_DYNALLOC, 64*1024*1024);

    xz_result = X_OK;
    while (1) {
        if (iobuf.in_pos == iobuf.in_size) {
            int rd = safe_read(xstate->src_fd, membuf, BUFSIZ);
            if (rd < 0) {
                bb_error_msg(bb_msg_read_error);
                total = -1;
                break;
            }
            if (rd == 0 && xz_result == XZ_STREAM_END)
                break;
            iobuf.in_size = rd;
            iobuf.in_pos = 0;
        }
        if (xz_result == XZ_STREAM_END) {
            /*
             * Try to start decoding next concatenated stream.
             * Stream padding must always be a multiple of four
             * bytes to preserve four-byte alignment. To keep the
             * code slightly smaller, we aren't as strict here as
             * the .xz spec requires. We just skip all zero-bytes
             * without checking the alignment and thus can accept
             * files that aren't valid, e.g. the XZ utils test
             * files bad-0pad-empty.xz and bad-0catpad-empty.xz.
             */
            do {
                if (membuf[iobuf.in_pos] != 0) {
                    xz_dec_reset(state);
                    goto do_run;
                }
                iobuf.in_pos++;
            } while (iobuf.in_pos < iobuf.in_size);
        }
 do_run:
//      bb_error_msg(">in pos:%d size:%d out pos:%d size:%d",
//              iobuf.in_pos, iobuf.in_size, iobuf.out_pos, iobuf.out_size);
        xz_result = xz_dec_run(state, &iobuf);
//      bb_error_msg("<in pos:%d size:%d out pos:%d size:%d r:%d",
//              iobuf.in_pos, iobuf.in_size, iobuf.out_pos, iobuf.out_size, xz_result);
        if (iobuf.out_pos) {
            xtransformer_write(xstate, iobuf.out, iobuf.out_pos);
            IF_DESKTOP(total += iobuf.out_pos;)
            iobuf.out_pos = 0;
        }
        if (xz_result == XZ_STREAM_END) {
            /*
             * Can just "break;" here, if not for concatenated
             * .xz streams.
             * Checking for padding may require buffer
             * replenishment. Can't do it here.
             */
            continue;
        }
        if (xz_result != XZ_OK && xz_result != XZ_UNSUPPORTED_CHECK) {
            bb_error_msg("corrupted data");
            total = -1;
            break;
        }
    }

    xz_dec_end(state);
    free(membuf);

    return total;
}