memzap

commit bb2230c5eaf520f3103555e4580bb8b78661925a
parent 03ed1051952b9238cf96d94635cc1af71f7d0e41
Author: sin <sin@2f30.org>
Date:   Mon,  4 Mar 2013 14:11:32 +0000

mem: Handle things properly when the blocksize is less than the diff pattern

Diffstat:
M
mdiff.c
 | 
2
+-
M
mem.c
 | 
18
+++++++++++++-----
M
memzap.c
 | 
3
+--

3 files changed, 15 insertions(+), 8 deletions(-)
diff --git a/mdiff.c b/mdiff.c
@@ -164,7 +164,7 @@ mdiff_append_rdiff(int fd, struct mem_region_diff *rdiff)
 		if (ret != (ssize_t)md->len)
 			err(1, "write");
 	}
-	return 0;
+	return i;
 }
 
 void
diff --git a/mem.c b/mem.c
@@ -256,16 +256,24 @@ diff_mem_region(struct mem_tree *dst,
 		find.weak_sum = mb->weak_sum;
 		me = RB_FIND(mem_tree, dst, &find);
 		if (me) {
-			/* We might have a weak sum collision
-			 * so check the strong sum as well */
 			for (j = 0; j < me->nmblks; j++) {
-				if (!memcmp(me->mblks[j]->digest,
-					    mb->digest,
-					    MD5_DIGEST_LENGTH)) {
+				if (me->mblks[j]->offset == mb->offset) {
 					found = true;
 					break;
 				}
 			}
+			if (found) {
+				/* We might have a weak sum collision
+				 * so check the strong sum as well */
+				for (j = 0; j < me->nmblks; j++) {
+					if (!memcmp(me->mblks[j]->digest,
+						    mb->digest,
+						    MD5_DIGEST_LENGTH)) {
+						found = true;
+						break;
+					}
+				}
+			}
 		}
 		if (!found) {
 			/* Cool, this is a modified block - update the rdiff */
diff --git a/memzap.c b/memzap.c
@@ -160,8 +160,7 @@ main(int argc, char *argv[])
 		rdiff = diff_mem_region(mt_old, mr_new);
 		if (rdiff->nmrdiffs) {
 			apply_diff(mr_old, rdiff);
-			mdiff_append_rdiff(fd, rdiff);
-			hdr.nregions++;
+			hdr.nregions += mdiff_append_rdiff(fd, rdiff);
 		}
 
 		free_mem_region(mr_old);