package null import ( "database/sql/driver" "encoding/json" "fmt" "reflect" "strconv" ) // NullInt16 is a replica of sql.NullInt64 for int16 types. type NullInt16 struct { Int16 int16 Valid bool } // Int16 is an nullable int16. // It does not consider zero values to be null. // It will decode to null, not zero, if null. type Int16 struct { NullInt16 } // NewInt16 creates a new Int16 func NewInt16(i int16, valid bool) Int16 { return Int16{ NullInt16: NullInt16{ Int16: i, Valid: valid, }, } } // Int16From creates a new Int16 that will always be valid. func Int16From(i int16) Int16 { return NewInt16(i, true) } // Int16FromPtr creates a new Int16 that be null if i is nil. func Int16FromPtr(i *int16) Int16 { if i == nil { return NewInt16(0, false) } return NewInt16(*i, true) } // UnmarshalJSON implements json.Unmarshaler. // It supports number and null input. // 0 will not be considered a null Int16. // It also supports unmarshalling a sql.NullInt16. func (i *Int16) UnmarshalJSON(data []byte) error { var err error var v interface{} if err = json.Unmarshal(data, &v); err != nil { return err } switch v.(type) { case float64: // Unmarshal again, directly to int16, to avoid intermediate float64 err = json.Unmarshal(data, &i.Int16) case map[string]interface{}: err = json.Unmarshal(data, &i.NullInt16) case nil: i.Valid = false return nil default: err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Int16", reflect.TypeOf(v).Name()) } i.Valid = err == nil return err } // UnmarshalText implements encoding.TextUnmarshaler. // It will unmarshal to a null Int16 if the input is a blank or not an integer. // It will return an error if the input is not an integer, blank, or "null". func (i *Int16) UnmarshalText(text []byte) error { str := string(text) if str == "" || str == "null" { i.Valid = false return nil } var err error res, err := strconv.ParseInt(string(text), 10, 16) i.Valid = err == nil if i.Valid { i.Int16 = int16(res) } return err } // MarshalJSON implements json.Marshaler. // It will encode null if this Int16 is null. func (i Int16) MarshalJSON() ([]byte, error) { if !i.Valid { return []byte("null"), nil } return []byte(strconv.FormatInt(int64(i.Int16), 10)), nil } // MarshalText implements encoding.TextMarshaler. // It will encode a blank string if this Int16 is null. func (i Int16) MarshalText() ([]byte, error) { if !i.Valid { return []byte{}, nil } return []byte(strconv.FormatInt(int64(i.Int16), 10)), nil } // SetValid changes this Int16's value and also sets it to be non-null. func (i *Int16) SetValid(n int16) { i.Int16 = n i.Valid = true } // Ptr returns a pointer to this Int16's value, or a nil pointer if this Int16 is null. func (i Int16) Ptr() *int16 { if !i.Valid { return nil } return &i.Int16 } // IsZero returns true for invalid Int16's, for future omitempty support (Go 1.4?) // A non-null Int16 with a 0 value will not be considered zero. func (i Int16) IsZero() bool { return !i.Valid } // Scan implements the Scanner interface. func (n *NullInt16) Scan(value interface{}) error { if value == nil { n.Int16, n.Valid = 0, false return nil } n.Valid = true return convertAssign(&n.Int16, value) } // Value implements the driver Valuer interface. func (n NullInt16) Value() (driver.Value, error) { if !n.Valid { return nil, nil } return n.Int16, nil }