1 files changed, 48 insertions, 1 deletions
diff --git a/object/id/object_format_ops.go b/object/id/object_format_ops.go
index 76077235..51bcae82 100644
--- a/object/id/object_format_ops.go
+++ b/object/id/object_format_ops.go
@@ -1,6 +1,10 @@
 package id
 
-import "hash"
+import (
+	"encoding/hex"
+	"fmt"
+	"hash"
+)
 
 // HexLen returns the encoded hexadecimal length.
 func (objectFormat ObjectFormat) HexLen() int {
@@ -22,6 +26,49 @@ func (objectFormat ObjectFormat) New() (hash.Hash, error) {
 	return newFn(), nil
 }
 
+// FromBytes builds an object ID from raw bytes for this object format.
+func (objectFormat ObjectFormat) FromBytes(b []byte) (ObjectID, error) {
+	var id ObjectID
+	if objectFormat.Size() == 0 {
+		return id, ErrInvalidObjectFormat
+	}
+
+	if len(b) != objectFormat.Size() {
+		return id, fmt.Errorf("%w: got %d bytes, expected %d", ErrInvalidObjectID, len(b), objectFormat.Size())
+	}
+
+	copy(id.data[:], b)
+	id.objectFormat = objectFormat
+
+	return id, nil
+}
+
+// FromString parses an object ID from its canonical hex representation.
+func (objectFormat ObjectFormat) FromString(s string) (ObjectID, error) {
+	var id ObjectID
+	if objectFormat.Size() == 0 {
+		return id, ErrInvalidObjectFormat
+	}
+
+	if len(s)&1 != 0 {
+		return id, fmt.Errorf("%w: odd hex length %d", ErrInvalidObjectID, len(s))
+	}
+
+	if len(s) != objectFormat.HexLen() {
+		return id, fmt.Errorf("%w: got %d chars, expected %d", ErrInvalidObjectID, len(s), objectFormat.HexLen())
+	}
+
+	decoded, err := hex.DecodeString(s)
+	if err != nil {
+		return id, fmt.Errorf("%w: decode: %w", ErrInvalidObjectID, err)
+	}
+
+	copy(id.data[:], decoded)
+	id.objectFormat = objectFormat
+
+	return id, nil
+}
+
 // String returns the canonical object format name.
 func (objectFormat ObjectFormat) String() string {
 	return objectFormat.details().name