Correct offset for object key

Author: magodo

pointer.go

@@ -398,6 +398,7 @@ func (p *Pointer) Offset(document string) (int64, error) {
 
 func offsetSingleObject(dec *json.Decoder, decodedToken string) (int64, error) {
 	for dec.More() {
+		offset := dec.InputOffset()
 		tk, err := dec.Token()
 		if err != nil {
 			return 0, err
@@ -416,7 +417,7 @@ func offsetSingleObject(dec *json.Decoder, decodedToken string) (int64, error) {
 			}
 		case string:
 			if tk == decodedToken {
-				return dec.InputOffset(), nil
+				return offset, nil
 			}
 		default:
 			return 0, fmt.Errorf("invalid token %#v", tk)

pointer_test.go

@@ -608,13 +608,13 @@ func TestOffset(t *testing.T) {
 			name:   "object key",
 			ptr:    "/foo/bar",
 			input:  `{"foo": {"bar": 21}}`,
-			offset: 14,
+			offset: 9,
 		},
 		{
 			name:   "complex object key",
 			ptr:    "/paths/~1p~1{}/get",
 			input:  `{"paths": {"foo": {"bar": 123, "baz": {}}, "/p/{}": {"get": {}}}}`,
-			offset: 58,
+			offset: 53,
 		},
 		{
 			name:   "array index",