Add method: (c *Cid) Cmp(o *Cid) int

Author: gagliardetto

cid.go

@@ -410,6 +410,20 @@ func (c Cid) Bytes() []byte {
 	return []byte(c.str)
 }
 
+// Cmp compares two Cids for binary sorting order.
+func (c *Cid) Cmp(o *Cid) int {
+	switch {
+	case c == o:
+		return 0
+	case c == nil:
+		return -1
+	case o == nil:
+		return 1
+	default:
+		return strings.Compare(c.str, o.str)
+	}
+}
+
 // ByteLen returns the length of the CID in bytes.
 // It's equivalent to `len(c.Bytes())`, but works without an allocation,
 // and should therefore be preferred.