Refactored Hash -> Sum and fixed infinite loop issue with SumAtoms

sum/sum.go

@@ -0,0 +1,37 @@
+// Copyright 2015, David Howden
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+/*
+The sum tool constructs a checksum of a media file exluding any metadata
+(as recognised by the tag library).
+*/
+package main
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/dhowden/tag"
+)
+
+func main() {
+	if len(os.Args) != 2 {
+		fmt.Printf("usage: %v filename\n", os.Args[0])
+		return
+	}
+
+	f, err := os.Open(os.Args[1])
+	if err != nil {
+		fmt.Printf("error loading file: %v", err)
+		os.Exit(1)
+	}
+	defer f.Close()
+
+	h, err := tag.Sum(f)
+	if err != nil {
+		fmt.Printf("error constructing checksum: %v\n", err)
+		os.Exit(1)
+	}
+	fmt.Println(h)
+}