rpm: code shrink. Now uses open_zipped's logic (factored out into setup_unzip_on_fd())

function                                             old     new   delta
setup_unzip_on_fd                                      -      80     +80
open_zipped                                          176     113     -63
rpm_main                                            1672    1355    -317
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/2 up/down: 80/-380)          Total: -300 bytes

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

1 files changed, 55 insertions, 42 deletions

diff --git a/libbb/read.c b/libbb/read.c
index 06ce29718..503216eb5 100644
--- a/libbb/read.c
+++ b/libbb/read.c
@@ -6,7 +6,6 @@
  *
  * Licensed under GPLv2 or later, see file LICENSE in this tarball for details.
  */
-
 #include "libbb.h"
 
 #define ZIPPED (ENABLE_FEATURE_SEAMLESS_LZMA \
@@ -16,7 +15,7 @@
 )
 
 #if ZIPPED
-#include "unarchive.h"
+# include "unarchive.h"
 #endif
 
 ssize_t FAST_FUNC safe_read(int fd, void *buf, size_t count)
@@ -306,14 +305,11 @@ void* FAST_FUNC xmalloc_xopen_read_close(const char *filename, size_t *maxsz_p)
         return buf;
 }
 
-int FAST_FUNC open_zipped(const char *fname)
+#if ZIPPED
+int FAST_FUNC setup_unzip_on_fd(int fd /*, int fail_if_not_detected*/)
 {
-#if !ZIPPED
-        return open(fname, O_RDONLY);
-#else
+        const int fail_if_not_detected = 1;
         unsigned char magic[2];
-        char *sfx;
-        int fd;
 #if BB_MMU
         IF_DESKTOP(long long) int FAST_FUNC (*xformer)(int src_fd, int dst_fd);
         enum { xformer_prog = 0 };
@@ -322,6 +318,56 @@ int FAST_FUNC open_zipped(const char *fname)
         const char *xformer_prog;
 #endif
 
+        /* .gz and .bz2 both have 2-byte signature, and their
+         * unpack_XXX_stream wants this header skipped. */
+        xread(fd, &magic, 2);
+#if ENABLE_FEATURE_SEAMLESS_GZ
+# if BB_MMU
+        xformer = unpack_gz_stream;
+# else
+        xformer_prog = "gunzip";
+# endif
+#endif
+        if (!ENABLE_FEATURE_SEAMLESS_GZ
+         || magic[0] != 0x1f || magic[1] != 0x8b
+        ) {
+                if (!ENABLE_FEATURE_SEAMLESS_BZ2
+                 || magic[0] != 'B' || magic[1] != 'Z'
+                ) {
+                        if (fail_if_not_detected)
+                                bb_error_msg_and_die("no gzip"
+                                        IF_FEATURE_SEAMLESS_BZ2("/bzip2")
+                                        " magic");
+                        xlseek(fd, -2, SEEK_CUR);
+                        return fd;
+                }
+#if BB_MMU
+                xformer = unpack_bz2_stream;
+#else
+                xformer_prog = "bunzip2";
+#endif
+        } else {
+#if !BB_MMU
+                /* NOMMU version of open_transformer execs
+                 * an external unzipper that wants
+                 * file position at the start of the file */
+                xlseek(fd, -2, SEEK_CUR);
+#endif
+        }
+        open_transformer(fd, xformer, xformer_prog);
+
+        return fd;
+}
+#endif /* ZIPPED */
+
+int FAST_FUNC open_zipped(const char *fname)
+{
+#if !ZIPPED
+        return open(fname, O_RDONLY);
+#else
+        char *sfx;
+        int fd;
+
         fd = open(fname, O_RDONLY);
         if (fd < 0)
                 return fd;
@@ -335,40 +381,7 @@ int FAST_FUNC open_zipped(const char *fname)
                 if ((ENABLE_FEATURE_SEAMLESS_GZ && strcmp(sfx, ".gz") == 0)
                  || (ENABLE_FEATURE_SEAMLESS_BZ2 && strcmp(sfx, ".bz2") == 0)
                 ) {
-                        /* .gz and .bz2 both have 2-byte signature, and their
-                         * unpack_XXX_stream wants this header skipped. */
-                        xread(fd, &magic, 2);
-#if ENABLE_FEATURE_SEAMLESS_GZ
-#if BB_MMU
-                        xformer = unpack_gz_stream;
-#else
-                        xformer_prog = "gunzip";
-#endif
-#endif
-                        if (!ENABLE_FEATURE_SEAMLESS_GZ
-                         || magic[0] != 0x1f || magic[1] != 0x8b
-                        ) {
-                                if (!ENABLE_FEATURE_SEAMLESS_BZ2
-                                 || magic[0] != 'B' || magic[1] != 'Z'
-                                ) {
-                                        bb_error_msg_and_die("no gzip"
-                                                IF_FEATURE_SEAMLESS_BZ2("/bzip2")
-                                                " magic");
-                                }
-#if BB_MMU
-                                xformer = unpack_bz2_stream;
-#else
-                                xformer_prog = "bunzip2";
-#endif
-                        } else {
-#if !BB_MMU
-                                /* NOMMU version of open_transformer execs
-                                 * an external unzipper that wants
-                                 * file position at the start of the file */
-                                xlseek(fd, 0, SEEK_SET);
-#endif
-                        }
-                        open_transformer(fd, xformer, xformer_prog);
+                        setup_unzip_on_fd(fd /*, fail_if_not_detected: 1*/);
                 }
         }