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authorDenys Vlasenko2010-06-02 14:14:48 +0200
committerDenys Vlasenko2010-06-02 14:14:48 +0200
commit26b6ccf340243ec3acd594c6928b18e95d3deea9 (patch)
tree90955d90056adbd8724db164f7cbb3e56833ed8b /libbb
parentabb154ba02f9a9a98465cb1f816f974cca536392 (diff)
downloadbusybox-26b6ccf340243ec3acd594c6928b18e95d3deea9.zip
busybox-26b6ccf340243ec3acd594c6928b18e95d3deea9.tar.gz
*: simplify checks for gz/bz2/xz magic
function old new delta send_tree 360 355 -5 rpm2cpio_main 249 220 -29 setup_unzip_on_fd 150 118 -32 ------------------------------------------------------------------------------ (add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-66) Total: -66 bytes Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Diffstat (limited to 'libbb')
-rw-r--r--libbb/read.c21
1 files changed, 13 insertions, 8 deletions
diff --git a/libbb/read.c b/libbb/read.c
index cd6bbeb..b1eb3f2 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -312,7 +312,11 @@ void* FAST_FUNC xmalloc_xopen_read_close(const char *filename, size_t *maxsz_p)
void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
{
const int fail_if_not_detected = 1;
- unsigned char magic[8];
+ union {
+ uint8_t b[4];
+ uint16_t b16[2];
+ uint32_t b32[1];
+ } magic;
int offset = -2;
# if BB_MMU
IF_DESKTOP(long long) int FAST_FUNC (*xformer)(int src_fd, int dst_fd);
@@ -324,9 +328,9 @@ void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
/* .gz and .bz2 both have 2-byte signature, and their
* unpack_XXX_stream wants this header skipped. */
- xread(fd, magic, 2);
+ xread(fd, magic.b16, sizeof(magic.b16));
if (ENABLE_FEATURE_SEAMLESS_GZ
- && magic[0] == 0x1f && magic[1] == 0x8b
+ && magic.b16[0] == GZIP_MAGIC
) {
# if BB_MMU
xformer = unpack_gz_stream;
@@ -336,7 +340,7 @@ void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
goto found_magic;
}
if (ENABLE_FEATURE_SEAMLESS_BZ2
- && magic[0] == 'B' && magic[1] == 'Z'
+ && magic.b16[0] == BZIP2_MAGIC
) {
# if BB_MMU
xformer = unpack_bz2_stream;
@@ -346,19 +350,20 @@ void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
goto found_magic;
}
if (ENABLE_FEATURE_SEAMLESS_XZ
- && magic[0] == 0xfd && magic[1] == '7'
+ && magic.b16[0] == XZ_MAGIC1
) {
/* .xz signature: 0xfd, '7', 'z', 'X', 'Z', 0x00 */
/* More info at: http://tukaani.org/xz/xz-file-format.txt */
offset = -6;
- xread(fd, magic + 2, 4);
- if (strcmp((char*)magic + 2, "zXZ") == 0) {
+ xread(fd, magic.b32, sizeof(magic.b32));
+ if (magic.b32[0] == XZ_MAGIC2) {
# if BB_MMU
xformer = unpack_xz_stream;
+ /* unpack_xz_stream wants fd at position 0 */
+ xlseek(fd, offset, SEEK_CUR);
# else
xformer_prog = "unxz";
# endif
- xlseek(fd, offset, SEEK_CUR);
goto found_magic;
}
}