Checksum returns bytes too (#238)

utils/checksum.go

@@ -45,6 +45,25 @@ func GetFileChecksums(filePath string, checksumType ...Algorithm) (checksums map
 
 // CalcChecksums calculates all hashes at once using AsyncMultiWriter. The file is therefore read only once.
 func CalcChecksums(reader io.Reader, checksumType ...Algorithm) (map[Algorithm]string, error) {
+	hashes, err := calcChecksums(reader, checksumType...)
+	if err != nil {
+		return nil, err
+	}
+	results := sumResults(hashes)
+	return results, nil
+}
+
+// CalcChecksumsBytes calculates hashes like `CalcChecksums`, returns result as bytes
+func CalcChecksumsBytes(reader io.Reader, checksumType ...Algorithm) (map[Algorithm][]byte, error) {
+	hashes, err := calcChecksums(reader, checksumType...)
+	if err != nil {
+		return nil, err
+	}
+	results := sumResultsBytes(hashes)
+	return results, nil
+}
+
+func calcChecksums(reader io.Reader, checksumType ...Algorithm) (map[Algorithm]hash.Hash, error) {
 	hashes := getChecksumByAlgorithm(checksumType...)
 	var multiWriter io.Writer
 	pageSize := os.Getpagesize()
@@ -58,8 +77,7 @@ func CalcChecksums(reader io.Reader, checksumType ...Algorithm) (map[Algorithm]s
 	if err != nil {
 		return nil, err
 	}
-	results := sumResults(hashes)
-	return results, nil
+	return hashes, nil
 }
 
 func sumResults(hashes map[Algorithm]hash.Hash) map[Algorithm]string {
@@ -70,6 +88,14 @@ func sumResults(hashes map[Algorithm]hash.Hash) map[Algorithm]string {
 	return results
 }
 
+func sumResultsBytes(hashes map[Algorithm]hash.Hash) map[Algorithm][]byte {
+	results := map[Algorithm][]byte{}
+	for k, v := range hashes {
+		results[k] = v.Sum(nil)
+	}
+	return results
+}
+
 func getChecksumByAlgorithm(checksumType ...Algorithm) map[Algorithm]hash.Hash {
 	hashes := map[Algorithm]hash.Hash{}
 	if len(checksumType) == 0 {