X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=count-delta.c;h=058a2aadb1475801ea7573837867fa79bf1766c1;hb=b0d08a504bee17dfc46f761e166ff2c20c59a91a;hp=8901034188c4d17be6676dd1fd532a23384cb5cb;hpb=69a2d426f0d249bca2c6f754b3c1283c0fa72fd4;p=git.git

diff --git a/count-delta.c b/count-delta.c
index 89010341..058a2aad 100644
--- a/count-delta.c
+++ b/count-delta.c
@@ -6,23 +6,9 @@
 #include <stdlib.h>
 #include <string.h>
 #include <limits.h>
+#include "delta.h"
 #include "count-delta.h"
 
-static unsigned long get_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) {
-		cmd = *data++;
-		size |= (cmd & ~0x80) << i;
-		i += 7;
-	}
-	*datap = data;
-	return size;
-}
-
 /*
  * NOTE.  We do not _interpret_ delta fully.  As an approximation, we
  * just count the number of bytes that are copied from the source, and
@@ -30,11 +16,7 @@ static unsigned long get_hdr_size(const unsigned char **datap)
  *
  * Number of bytes that are _not_ copied from the source is deletion,
  * and number of inserted literal bytes are addition, so sum of them
- * is the extent of damage.  xdelta can express an edit that copies
- * data inside of the destination which originally came from the
- * source.  We do not count that in the following routine, so we are
- * undercounting the source material that remains in the final output
- * that way.
+ * is the extent of damage.
  */
 int count_delta(void *delta_buf, unsigned long delta_size,
 		unsigned long *src_copied, unsigned long *literal_added)
@@ -44,15 +26,14 @@ int count_delta(void *delta_buf, unsigned long delta_size,
 	unsigned char cmd;
 	unsigned long src_size, dst_size, out;
 
-	/* the smallest delta size possible is 4 bytes */
-	if (delta_size < 4)
+	if (delta_size < DELTA_SIZE_MIN)
 		return -1;
 
 	data = delta_buf;
 	top = delta_buf + delta_size;
 
-	src_size = get_hdr_size(&data);
-	dst_size = get_hdr_size(&data);
+	src_size = get_delta_hdr_size(&data);
+	dst_size = get_delta_hdr_size(&data);
 
 	added_literal = copied_from_source = out = 0;
 	while (data < top) {
@@ -65,13 +46,10 @@ int count_delta(void *delta_buf, unsigned long delta_size,
 			if (cmd & 0x08) cp_off |= (*data++ << 24);
 			if (cmd & 0x10) cp_size = *data++;
 			if (cmd & 0x20) cp_size |= (*data++ << 8);
+			if (cmd & 0x40) cp_size |= (*data++ << 16);
 			if (cp_size == 0) cp_size = 0x10000;
 
-			if (cmd & 0x40)
-				/* copy from dst */
-				;
-			else
-				copied_from_source += cp_size;
+			copied_from_source += cp_size;
 			out += cp_size;
 		} else {
 			/* write literal into dst */