support-convert-slice-to-int64

cast.go

@@ -169,6 +169,12 @@ func ToIntSlice(i interface{}) []int {
 	return v
 }
 
+// ToInt64Slice casts an interface to a []int64 type.
+func ToInt64Slice(i interface{}) []int64 {
+	v, _ := ToInt64SliceE(i)
+	return v
+}
+
 // ToDurationSlice casts an interface to a []time.Duration type.
 func ToDurationSlice(i interface{}) []time.Duration {
 	v, _ := ToDurationSliceE(i)

cast_test.go

@@ -1014,6 +1014,40 @@ func TestToIntSliceE(t *testing.T) {
 	}
 }
 
+func TestToInt64SliceE(t *testing.T) {
+	tests := []struct {
+		input  interface{}
+		expect []int64
+		iserr  bool
+	}{
+		{[]int{1, 3}, []int64{1, 3}, false},
+		{[]interface{}{1.2, 3.2}, []int64{1, 3}, false},
+		{[]string{"2", "3"}, []int64{2, 3}, false},
+		{[2]string{"2", "3"}, []int64{2, 3}, false},
+		// errors
+		{nil, nil, true},
+		{testing.T{}, nil, true},
+		{[]string{"foo", "bar"}, nil, true},
+	}
+
+	for i, test := range tests {
+		errmsg := fmt.Sprintf("i = %d", i) // assert helper message
+
+		v, err := ToInt64SliceE(test.input)
+		if test.iserr {
+			assert.Error(t, err, errmsg)
+			continue
+		}
+
+		assert.NoError(t, err, errmsg)
+		assert.Equal(t, test.expect, v, errmsg)
+
+		// Non-E test
+		v = ToInt64Slice(test.input)
+		assert.Equal(t, test.expect, v, errmsg)
+	}
+}
+
 func TestToSliceE(t *testing.T) {
 	tests := []struct {
 		input  interface{}

caste.go

@@ -1184,6 +1184,35 @@ func ToStringSliceE(i interface{}) ([]string, error) {
 	}
 }
 
+// ToIntSliceE casts an interface to a []int64 type.
+func ToInt64SliceE(i interface{}) ([]int64, error) {
+	if i == nil {
+		return []int64{}, fmt.Errorf("unable to cast %#v of type %T to []int", i, i)
+	}
+
+	switch v := i.(type) {
+	case []int64:
+		return v, nil
+	}
+
+	kind := reflect.TypeOf(i).Kind()
+	switch kind {
+	case reflect.Slice, reflect.Array:
+		s := reflect.ValueOf(i)
+		a := make([]int64, s.Len())
+		for j := 0; j < s.Len(); j++ {
+			val, err := ToInt64E(s.Index(j).Interface())
+			if err != nil {
+				return []int64{}, fmt.Errorf("unable to cast %#v of type %T to []int", i, i)
+			}
+			a[j] = val
+		}
+		return a, nil
+	default:
+		return []int64{}, fmt.Errorf("unable to cast %#v of type %T to []int", i, i)
+	}
+}
+
 // ToIntSliceE casts an interface to a []int type.
 func ToIntSliceE(i interface{}) ([]int, error) {
 	if i == nil {