delta micro optimization

My kernel work habit made me look at the generated assembly for the
delta code, and one obvious albeit small improvement is this patch.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Junio C Hamano <junkio@cox.net>

diff --git a/delta.h b/delta.h
index 31d1820..a15350d 100644 (file)
--- a/delta.h
+++ b/delta.h
@@ -19,14 +19,14 @@ extern void *patch_delta(void *src_buf, unsigned long src_size,
 static inline unsigned long get_delta_hdr_size(const unsigned char **datap)
 {
        const unsigned char *data = *datap;
-       unsigned char cmd = *data++;
-       unsigned long size = cmd & ~0x80;
-       int i = 7;
-       while (cmd & 0x80) {
+       unsigned char cmd;
+       unsigned long size = 0;
+       int i = 0;
+       do {
                cmd = *data++;
                size |= (cmd & ~0x80) << i;
                i += 7;
-       }
+       } while (cmd & 0x80);
        *datap = data;
        return size;
 }