添加md5流式计算

md5x/md5x.go

@@ -22,7 +22,15 @@ func Md5File(path string) (string, error) {
 	}
 	defer file.Close()
 
+	return Md5Stream(file)
+}
+
+// 流式的md5
+func Md5Stream(reader io.Reader) (string, error) {
 	hash := md5.New()
-	io.Copy(hash, file)
+	_, err := io.Copy(hash, reader)
+	if err != nil {
+		return "", err
+	}
 	return hex.EncodeToString(hash.Sum(nil)), nil
 }