X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=diff-delta.c;h=5bc22047f8715b0b1e628ab5ba93afa68e2ccc9e;hb=42d0ee8302c361a0e3bde7bc59858eda94bc13a4;hp=aaee7be4d20dade99d351f6bdd70632cf249230e;hpb=2593a410e095f89f0eef40edb90b39029574462b;p=git.git

diff --git a/diff-delta.c b/diff-delta.c
index aaee7be4..5bc22047 100644
--- a/diff-delta.c
+++ b/diff-delta.c
@@ -131,12 +131,13 @@ static struct index ** delta_index(const unsigned char *buf,
 /* the maximum size for any opcode */
 #define MAX_OP_SIZE COPYOP_SIZE(0xffffffff, 0xffffffff)
 
-void *diff_delta(void *from_buf, unsigned long from_size,
-		 void *to_buf, unsigned long to_size,
+void *diff_delta(const void *from_buf, unsigned long from_size,
+		 const void *to_buf, unsigned long to_size,
 		 unsigned long *delta_size,
 		 unsigned long max_size)
 {
-	unsigned int i, outpos, outsize, inscnt, hash_shift;
+	unsigned int i, outpos, outsize, hash_shift;
+	int inscnt;
 	const unsigned char *ref_data, *ref_top, *data, *top;
 	unsigned char *out;
 	struct index *entry, **hash;
@@ -222,6 +223,20 @@ void *diff_delta(void *from_buf, unsigned long from_size,
 			unsigned char *op;
 
 			if (inscnt) {
+				while (moff && ref_data[moff-1] == data[-1]) {
+					if (msize == 0x10000)
+						break;
+					/* we can match one byte back */
+					msize++;
+					moff--;
+					data--;
+					outpos--;
+					if (--inscnt)
+						continue;
+					outpos--;  /* remove count slot */
+					inscnt--;  /* make it -1 */
+					break;
+				}
 				out[outpos - inscnt - 1] = inscnt;
 				inscnt = 0;
 			}