busybox/archival/libarchive/decompress_unxz.c
Denys Vlasenko b4c11c1397 libarchive: add capability to unpack to mem.buffer
The performance and number of processes for a "depmod -a" with gzipped
modules was abysmal. This patch adds a code path without fork,
benefiting all users of xmalloc_open_zipped_read_close.

"modinfo radeon.ko.gz", a single-file reader, got 30% faster.
"depmod -a", which used to fork over 800 times, got 20% faster.

Heavily based on a patch by Lauri Kasanen <curaga@operamail.com>

function                                             old     new   delta
setup_transformer_on_fd                                -     159    +159
transformer_write                                      -     122    +122
fork_transformer                                       -     112    +112
xmalloc_open_zipped_read_close                        63     118     +55
read_bunzip                                         1866    1896     +30
xtransformer_write                                     -      19     +19
unzip_main                                          2449    2462     +13
bbunpack                                             755     766     +11
unpack_lzma_stream                                  2717    2723      +6
unpack_xz_stream                                    2393    2397      +4
unpack_Z_stream                                     1173    1175      +2
inflate_unzip                                        111     105      -6
check_signature16                                     70      63      -7
unpack_bz2_stream                                    359     349     -10
unpack_unxz                                           12       -     -12
unpack_unlzma                                         12       -     -12
unpack_uncompress                                     12       -     -12
unpack_gunzip                                         12       -     -12
unpack_bunzip2                                        12       -     -12
open_transformer                                     106      92     -14
inflate_unzip_internal                              1945    1916     -29
unpack_gz_stream                                     693     655     -38
open_zipped                                           89      47     -42
setup_unzip_on_fd                                    142      53     -89
------------------------------------------------------------------------------
(add/remove: 4/5 grow/shrink: 7/8 up/down: 533/-295)          Total: 238 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2014-12-07 00:44:00 +01:00

132 lines
3.8 KiB
C

/*
* 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->check_signature == 0) {
/* 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;
}