xz compression detection: avoid the need to seek

function                                             old     new   delta
unpack_unxz                                           12      67     +55
unpack_xz_stream                                    2357    2373     +16
xmalloc_read                                         197     199      +2
setup_unzip_on_fd                                    118      99     -19
rpm2cpio_main                                        222     203     -19
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 3/2 up/down: 73/-38)             Total: 35 bytes

Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/libbb/read_printf.c b/libbb/read_printf.c
index 3aee075c6..6780b94ef 100644
--- a/libbb/read_printf.c
+++ b/libbb/read_printf.c
@@ -296,8 +296,8 @@ void FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
                 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);
+                        /* unpack_xz_stream wants fd at position 6, no need to seek */
+                        //xlseek(fd, offset, SEEK_CUR);
 # else
                         xformer_prog = "unxz";
 # endif