From 26b6ccf340243ec3acd594c6928b18e95d3deea9 Mon Sep 17 00:00:00 2001 From: Denys Vlasenko Date: Wed, 2 Jun 2010 14:14:48 +0200 Subject: [PATCH] *: 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 --- archival/rpm2cpio.c | 19 ++++++++++++------- include/unarchive.h | 16 ++++++++++++++++ libbb/read.c | 21 +++++++++++++-------- 3 files changed, 41 insertions(+), 15 deletions(-) diff --git a/archival/rpm2cpio.c b/archival/rpm2cpio.c index 598ec8670..1c67dcc6e 100644 --- a/archival/rpm2cpio.c +++ b/archival/rpm2cpio.c @@ -68,26 +68,31 @@ int rpm2cpio_main(int argc UNUSED_PARAM, char **argv) #else /* BLOAT */ { - unsigned char magic[8]; + union { + uint8_t b[4]; + uint16_t b16[2]; + uint32_t b32[1]; + } magic; IF_DESKTOP(long long) int FAST_FUNC (*unpack)(int src_fd, int dst_fd); - xread(rpm_fd, &magic, 2); - if (magic[0] == 0x1f && magic[1] == 0x8b) { + xread(rpm_fd, magic.b16, sizeof(magic.b16)); + if (magic.b16[0] == GZIP_MAGIC) { unpack = unpack_gz_stream; } else if (ENABLE_FEATURE_SEAMLESS_BZ2 - && magic[0] == 'B' && magic[1] == 'Z' + && magic.b16[0] == BZIP2_MAGIC ) { unpack = unpack_bz2_stream; } else 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 */ - xread(rpm_fd, magic + 2, 4); - if (strcmp((char*)magic + 2, "zXZ") != 0) + xread(rpm_fd, magic.b32, sizeof(magic.b32)); + if (magic.b32[0] != XZ_MAGIC2) goto no_magic; + /* unpack_xz_stream wants fd at position 0 */ xlseek(rpm_fd, -6, SEEK_CUR); unpack = unpack_xz_stream; } else { diff --git a/include/unarchive.h b/include/unarchive.h index aa7ecec55..8009de282 100644 --- a/include/unarchive.h +++ b/include/unarchive.h @@ -4,6 +4,22 @@ PUSH_AND_SET_FUNCTION_VISIBILITY_TO_HIDDEN +enum { +#if BB_BIG_ENDIAN + COMPRESS_MAGIC = 0x1f9d, + GZIP_MAGIC = 0x1f8b, + BZIP2_MAGIC = ('B'<<8) + 'Z', + XZ_MAGIC1 = (0xfd<<8) + '7', + XZ_MAGIC2 = ((((('z'<<8) + 'X')<<8) + 'Z')<<8) + 0, +#else + COMPRESS_MAGIC = 0x9d1f, + GZIP_MAGIC = 0x8b1f, + BZIP2_MAGIC = ('Z'<<8) + 'B', + XZ_MAGIC1 = ('7'<<8) + 0xfd, + XZ_MAGIC2 = (((((0<<8) + 'Z')<<8) + 'X')<<8) + 'z', +#endif +}; + typedef struct file_header_t { char *name; char *link_target; diff --git a/libbb/read.c b/libbb/read.c index cd6bbeb13..b1eb3f24b 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; } } -- 2.25.1