Merge pull request libgit2#28 from Merovius/shorten

Implement ShortenOids

Author: Vicent Martí

git.go

@@ -96,6 +96,26 @@ func (oid *Oid) NCmp(oid2 *Oid, n uint) int {
 	return bytes.Compare(oid.bytes[:n], oid2.bytes[:n])
 }
 
+func ShortenOids(ids []*Oid, minlen int) (int, error) {
+	shorten := C.git_oid_shorten_new(C.size_t(minlen))
+	if shorten == nil {
+		panic("Out of memory")
+	}
+	defer C.git_oid_shorten_free(shorten)
+
+	var ret C.int
+	for _, id := range ids {
+		buf := make([]byte, 41)
+		C.git_oid_fmt((*C.char)(unsafe.Pointer(&buf[0])), id.toC())
+		buf[40] = 0
+		ret = C.git_oid_shorten_add(shorten, (*C.char)(unsafe.Pointer(&buf[0])))
+		if ret < 0 {
+			return int(ret), LastError()
+		}
+	}
+	return int(ret), nil
+}
+
 type GitError struct {
 	Message string
 	Code int