*: 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>

1 files changed, 16 insertions, 0 deletions

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;