libarchive: treat one "FIXME: avoid seek"

function                                             old     new   delta
xmalloc_read_with_initial_buf                          -     205    +205
setup_transformer_on_fd                              154     150      -4
xmalloc_open_zipped_read_close                       143     135      -8
xmalloc_read                                         201      10    -191
------------------------------------------------------------------------------
(add/remove: 1/0 grow/shrink: 0/3 up/down: 205/-203)            Total: 2 bytes

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

2 files changed, 7 insertions, 0 deletions

diff --git a/include/bb_archive.h b/include/bb_archive.h
index 561dd0c9d..9b1db5b3e 100644
--- a/include/bb_archive.h
+++ b/include/bb_archive.h
@@ -235,6 +235,12 @@ typedef struct transformer_state_t {
         off_t    bytes_in;  /* used in unzip code only: needs to know packed size */
         uint32_t crc32;
         time_t   mtime;     /* gunzip code may set this on exit */
+
+        union {             /* if we read magic, it's saved here */
+                uint8_t b[8];
+                uint16_t b16[4];
+                uint32_t b32[2];
+        } magic;
 } transformer_state_t;
 
 void init_transformer_state(transformer_state_t *xstate) FAST_FUNC;
diff --git a/include/libbb.h b/include/libbb.h
index 57cfce385..33766e989 100644
--- a/include/libbb.h
+++ b/include/libbb.h
@@ -881,6 +881,7 @@ extern ssize_t open_read_close(const char *filename, void *buf, size_t maxsz) FA
 extern char *xmalloc_reads(int fd, size_t *maxsz_p) FAST_FUNC;
 /* Reads block up to *maxsz_p (default: INT_MAX - 4095) */
 extern void *xmalloc_read(int fd, size_t *maxsz_p) FAST_FUNC RETURNS_MALLOC;
+extern void *xmalloc_read_with_initial_buf(int fd, size_t *maxsz_p, char *buf, size_t total) FAST_FUNC;
 /* Returns NULL if file can't be opened (default max size: INT_MAX - 4095) */
 extern void *xmalloc_open_read_close(const char *filename, size_t *maxsz_p) FAST_FUNC RETURNS_MALLOC;
 /* Never returns NULL */