feat: add int64 methods (#12)

iid.go

@@ -60,6 +60,11 @@ func FromUint64(i uint64) (Iid) {
 	return Iid(b)
 }
 
+// FromInt imports an existing Iid from its int64 representation.
+func FromInt(i int64) (Iid) {
+	return FromUint64(uint64(i))
+}
+
 // Iid represents time sortable ID which can be exported as a base64url encoded string or uint64.
 type Iid []byte
 
@@ -72,3 +77,8 @@ func (i Iid) String() string {
 func (i Iid) Uint64() uint64 {
 	return binary.BigEndian.Uint64(i)
 }
+
+// Int returns a int64 representing the Iid.
+func (i Iid) Int() int64 {
+	return int64(i.Uint64())
+}

iid_test.go

@@ -84,6 +84,23 @@ func ExampleFromUint64() {
 	// Output: 6711382541547442289
 }
 
+func TestFromInt(t *testing.T) {
+	ex := New()
+	i := int64(binary.BigEndian.Uint64(ex))
+
+	id := FromInt(i)
+
+	assert.Equal(t, ex, id)
+}
+
+func ExampleFromInt() {
+	var i int64 = 6711382541547442289
+	id := FromInt(i)
+
+	fmt.Println(id.Int())
+	// Output: 6711382541547442289
+}
+
 func TestIid_String(t *testing.T) {
 	ex := New()
 
@@ -102,3 +119,12 @@ func TestIid_Uint64(t *testing.T) {
 	id := FromUint64(i)
 	assert.Equal(t, ex, id)
 }
+
+func TestIid_Int(t *testing.T) {
+	ex := New()
+
+	i := ex.Int()
+
+	id := FromInt(i)
+	assert.Equal(t, ex, id)
+}