Commit Graph

12 Commits

Author SHA1 Message Date
Denys Vlasenko
590402bb55 unlzma: expand comments, no code changes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-01-09 14:28:25 +01:00
Denys Vlasenko
3989e5adf4 unlzma: fix erroneous "while" instead of "if". Closes 4682
These parts of the code essentially check whether
stepping back by rep0 goes negative or not.

LZMA SDK from lzma1604.7z has the following in the corresponding places:

... = dic[dicPos - rep0 + (dicPos < rep0 ? dicBufSize : 0)]

Clearly, not loop here.

Technically, "while" here works: if condition is false (because pos
underflowed), it iterates once, adds header.dict_size (a.k.a. dicBufSize),
this makes pos positive but smaller than header.dict_size, and loop exits.

Now we'll just check for negative result of subtraction, which is less code:

function                                             old     new   delta
unpack_lzma_stream                                  2659    2641     -18

(I hope 2 Gbyte+ dictionaries won't be in use soon).

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2017-01-09 14:02:55 +01:00
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
Denys Vlasenko
e7800f351a Rename transformer_aux_data_t -> transformer_state_t
No code changes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2014-12-07 00:42:49 +01:00
Denys Vlasenko
81071e6872 unlzma: add comments about possible bug from BZ 2689
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2014-02-28 15:42:10 +01:00
Denys Vlasenko
2108a6f0b5 unlzma: move some variables in "more local" scope
No code changes as verified by objdump

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2014-02-28 15:05:43 +01:00
Denys Vlasenko
507f6ea6d2 decompress_unlzma: move function, no code changes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2013-03-01 14:48:10 +01:00
Denys Vlasenko
a2d04e0702 decompress_unlzma: 10% speedup in "small" code
text	   data	    bss	    dec	    hex	filename
   1796	      0	      0	   1796	    704	decompress_unlzma.o
   1801	      0	      0	   1801	    709	decompress_unlzma.o

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2013-03-01 14:43:07 +01:00
Denys Vlasenko
c09fd27c0a decompress_unlzma: make "fast" version a bit smaller
It is not slower. In fact it seems a tiny bit faster too.

   text	   data	    bss	    dec	    hex	filename
   2827	      0	      0	   2827	    b0b	decompress_unlzma.o
   2797	      0	      0	   2797	    aed	decompress_unlzma.o

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2013-03-01 14:37:58 +01:00
Denys Vlasenko
8a6a2f9c9c update seamless uncompression code
This change makes "tar tf hello_world.txz" work without
adding special-casing for ".txz" extension. It also removes
ever-growing magic checking code in rpm2cpio and get_header_tar -
we reuse one which lives in setup_unzip_on_fd.

function                                             old     new   delta
unpack_gz_stream                                       7     566    +559
check_signature16                                      -      70     +70
setup_unzip_on_fd                                     99     142     +43
handle_SIGCHLD                                         -      41     +41
unpack_bz2_stream                                    342     376     +34
unzip_main                                          2352    2385     +33
bbunpack                                             503     533     +30
open_transformer                                      74     102     +28
unpack_Z_stream                                     1278    1304     +26
unpack_gunzip                                        101     123     +22
init_transformer_aux_data                              -      18     +18
unpack_xz_stream                                    2388    2402     +14
open_zipped                                          131     141     +10
rpm_main                                            1358    1363      +5
get_header_tar_lzma                                   52      57      +5
get_header_tar_bz2                                    52      57      +5
unpack_lzma_stream                                  2698    2702      +4
hash_find                                            234     233      -1
get_header_tar                                      1759    1733     -26
get_header_tar_gz                                     92      57     -35
unpack_uncompress                                     51      12     -39
rpm2cpio_main                                        201     147     -54
unpack_unxz                                           67      12     -55
unpack_bz2_stream_prime                               55       -     -55
get_header_tar_Z                                      86       -     -86
unpack_gz_stream_with_info                           539       -    -539
------------------------------------------------------------------------------
(add/remove: 3/3 grow/shrink: 14/6 up/down: 947/-890)          Total: 57 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2012-03-06 16:27:48 +01:00
Denys Vlasenko
d184a728cf rename archive.h to bb_archive.h. no code changes
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2011-09-22 12:45:14 +02:00
Denys Vlasenko
833d4e7f84 rename archival/libunarchive -> archival/libarchive; move bz/ into it
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
2010-11-03 02:38:31 +01:00