Commit 8564a0224abe09beaacb2d2e7a54b16f8fcea7d1
2013-04-29T08:51:24
Fix fragile git_oid_ncmp git_oid_ncmp was making some assumptions about the length of the data - this shifts the check to the top of the loop so it will work more robustly, limits the max, and adds some tests to verify the functionality.
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diff --git a/src/oid.c b/src/oid.c
index 59c1546..4b66990 100644
--- a/src/oid.c
+++ b/src/oid.c
@@ -176,13 +176,16 @@ int git_oid_ncmp(const git_oid *oid_a, const git_oid *oid_b, size_t len)
const unsigned char *a = oid_a->id;
const unsigned char *b = oid_b->id;
- do {
+ if (len > GIT_OID_HEXSZ)
+ len = GIT_OID_HEXSZ;
+
+ while (len > 1) {
if (*a != *b)
return 1;
a++;
b++;
len -= 2;
- } while (len > 1);
+ };
if (len)
if ((*a ^ *b) & 0xf0)
diff --git a/tests-clar/core/oid.c b/tests-clar/core/oid.c
index 08791cc..d863a3e 100644
--- a/tests-clar/core/oid.c
+++ b/tests-clar/core/oid.c
@@ -27,4 +27,22 @@ void test_core_oid__streq(void)
cl_assert(git_oid_streq(&idp, "deadbeef") == -1);
cl_assert(git_oid_streq(&idp, "I'm not an oid.... :)") == -1);
+
+void test_core_oid__ncmp(void)
+{
+ cl_assert(!git_oid_ncmp(&id, &idp, 0));
+ cl_assert(!git_oid_ncmp(&id, &idp, 1));
+ cl_assert(!git_oid_ncmp(&id, &idp, 2));
+ cl_assert(!git_oid_ncmp(&id, &idp, 17));
+ cl_assert(!git_oid_ncmp(&id, &idp, 18));
+ cl_assert(git_oid_ncmp(&id, &idp, 19));
+ cl_assert(git_oid_ncmp(&id, &idp, 40));
+ cl_assert(git_oid_ncmp(&id, &idp, 41));
+ cl_assert(git_oid_ncmp(&id, &idp, 42));
+
+ cl_assert(!git_oid_ncmp(&id, &id, 0));
+ cl_assert(!git_oid_ncmp(&id, &id, 1));
+ cl_assert(!git_oid_ncmp(&id, &id, 39));
+ cl_assert(!git_oid_ncmp(&id, &id, 40));
+ cl_assert(!git_oid_ncmp(&id, &id, 41));
}