Implement Modrinth pack exporting (fixes #34)

core/hash.go

@@ -5,23 +5,44 @@ import (
 	"crypto/sha1"
 	"crypto/sha256"
 	"crypto/sha512"
-	"errors"
+	"encoding/binary"
+	"encoding/hex"
+	"fmt"
+	"github.com/packwiz/packwiz/curseforge/murmur2"
 	"hash"
+	"strconv"
 	"strings"
 )
 
 // GetHashImpl gets an implementation of hash.Hash for the given hash type string
-func GetHashImpl(hashType string) (hash.Hash, error) {
+func GetHashImpl(hashType string) (hash.Hash, HashStringer, error) {
 	switch strings.ToLower(hashType) {
 	case "sha1":
-		return sha1.New(), nil
+		return sha1.New(), hexStringer{}, nil
 	case "sha256":
-		return sha256.New(), nil
+		return sha256.New(), hexStringer{}, nil
 	case "sha512":
-		return sha512.New(), nil
+		return sha512.New(), hexStringer{}, nil
 	case "md5":
-		return md5.New(), nil
+		return md5.New(), hexStringer{}, nil
+	case "murmur2":
+		return murmur2.New(), numberStringer{}, nil
 	}
-	// TODO: implement murmur2
-	return nil, errors.New("hash implementation not found")
+	return nil, nil, fmt.Errorf("hash implementation %s not found", hashType)
+}
+
+type HashStringer interface {
+	HashToString([]byte) string
+}
+
+type hexStringer struct{}
+
+func (hexStringer) HashToString(data []byte) string {
+	return hex.EncodeToString(data)
+}
+
+type numberStringer struct{}
+
+func (numberStringer) HashToString(data []byte) string {
+	return strconv.FormatUint(uint64(binary.BigEndian.Uint32(data)), 10)
 }