lbry.go/int32.go
2016-11-11 01:00:05 +10:00

130 lines
2.5 KiB
Go

package null
import (
"bytes"
"database/sql/driver"
"encoding/json"
"fmt"
"math"
"strconv"
"gopkg.in/nullbio/null.v5/convert"
)
// Int32 is an nullable int32.
type Int32 struct {
Int32 int32
Valid bool
}
// NewInt32 creates a new Int32
func NewInt32(i int32, valid bool) Int32 {
return Int32{
Int32: i,
Valid: valid,
}
}
// Int32From creates a new Int32 that will always be valid.
func Int32From(i int32) Int32 {
return NewInt32(i, true)
}
// Int32FromPtr creates a new Int32 that be null if i is nil.
func Int32FromPtr(i *int32) Int32 {
if i == nil {
return NewInt32(0, false)
}
return NewInt32(*i, true)
}
// UnmarshalJSON implements json.Unmarshaler.
func (i *Int32) UnmarshalJSON(data []byte) error {
if bytes.Equal(data, NullBytes) {
i.Valid = false
i.Int32 = 0
return nil
}
var x int64
if err := json.Unmarshal(data, &x); err != nil {
return err
}
if x > math.MaxInt32 {
return fmt.Errorf("json: %d overflows max int32 value", x)
}
i.Int32 = int32(x)
i.Valid = true
return nil
}
// UnmarshalText implements encoding.TextUnmarshaler.
func (i *Int32) 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, 32)
i.Valid = err == nil
if i.Valid {
i.Int32 = int32(res)
}
return err
}
// MarshalJSON implements json.Marshaler.
func (i Int32) MarshalJSON() ([]byte, error) {
if !i.Valid {
return []byte("null"), nil
}
return []byte(strconv.FormatInt(int64(i.Int32), 10)), nil
}
// MarshalText implements encoding.TextMarshaler.
func (i Int32) MarshalText() ([]byte, error) {
if !i.Valid {
return []byte{}, nil
}
return []byte(strconv.FormatInt(int64(i.Int32), 10)), nil
}
// SetValid changes this Int32's value and also sets it to be non-null.
func (i *Int32) SetValid(n int32) {
i.Int32 = n
i.Valid = true
}
// Ptr returns a pointer to this Int32's value, or a nil pointer if this Int32 is null.
func (i Int32) Ptr() *int32 {
if !i.Valid {
return nil
}
return &i.Int32
}
// IsZero returns true for invalid Int32's, for future omitempty support (Go 1.4?)
func (i Int32) IsZero() bool {
return !i.Valid
}
// Scan implements the Scanner interface.
func (i *Int32) Scan(value interface{}) error {
if value == nil {
i.Int32, i.Valid = 0, false
return nil
}
i.Valid = true
return convert.ConvertAssign(&i.Int32, value)
}
// Value implements the driver Valuer interface.
func (i Int32) Value() (driver.Value, error) {
if !i.Valid {
return nil, nil
}
return int64(i.Int32), nil
}