lbry.go/uint8.go
2016-09-07 21:33:21 +10:00

147 lines
3.4 KiB
Go

package null
import (
"database/sql/driver"
"encoding/json"
"fmt"
"reflect"
"strconv"
"gopkg.in/nullbio/null.v5/convert"
)
// NullUint8 is a replica of sql.NullInt64 for uint8 types.
type NullUint8 struct {
Uint8 uint8
Valid bool
}
// Uint8 is an nullable uint8.
// It does not consider zero values to be null.
// It will decode to null, not zero, if null.
type Uint8 struct {
NullUint8
}
// NewUint8 creates a new Uint8
func NewUint8(i uint8, valid bool) Uint8 {
return Uint8{
NullUint8: NullUint8{
Uint8: i,
Valid: valid,
},
}
}
// Uint8From creates a new Uint8 that will always be valid.
func Uint8From(i uint8) Uint8 {
return NewUint8(i, true)
}
// Uint8FromPtr creates a new Uint8 that be null if i is nil.
func Uint8FromPtr(i *uint8) Uint8 {
if i == nil {
return NewUint8(0, false)
}
return NewUint8(*i, true)
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will not be considered a null Uint8.
// It also supports unmarshalling a sql.NullUint8.
func (i *Uint8) 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 uint8, to avoid intermediate float64
err = json.Unmarshal(data, &i.Uint8)
case map[string]interface{}:
err = json.Unmarshal(data, &i.NullUint8)
case nil:
i.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Uint8", reflect.TypeOf(v).Name())
}
i.Valid = err == nil
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Uint8 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 *Uint8) UnmarshalText(text []byte) error {
str := string(text)
if str == "" || str == "null" {
i.Valid = false
return nil
}
var err error
res, err := strconv.ParseUint(string(text), 10, 8)
i.Valid = err == nil
if i.Valid {
i.Uint8 = uint8(res)
}
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Uint8 is null.
func (i Uint8) MarshalJSON() ([]byte, error) {
if !i.Valid {
return []byte("null"), nil
}
return []byte(strconv.FormatUint(uint64(i.Uint8), 10)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a blank string if this Uint8 is null.
func (i Uint8) MarshalText() ([]byte, error) {
if !i.Valid {
return []byte{}, nil
}
return []byte(strconv.FormatUint(uint64(i.Uint8), 10)), nil
}
// SetValid changes this Uint8's value and also sets it to be non-null.
func (i *Uint8) SetValid(n uint8) {
i.Uint8 = n
i.Valid = true
}
// Ptr returns a pointer to this Uint8's value, or a nil pointer if this Uint8 is null.
func (i Uint8) Ptr() *uint8 {
if !i.Valid {
return nil
}
return &i.Uint8
}
// IsZero returns true for invalid Uint8's, for future omitempty support (Go 1.4?)
// A non-null Uint8 with a 0 value will not be considered zero.
func (i Uint8) IsZero() bool {
return !i.Valid
}
// Scan implements the Scanner interface.
func (n *NullUint8) Scan(value interface{}) error {
if value == nil {
n.Uint8, n.Valid = 0, false
return nil
}
n.Valid = true
return convert.ConvertAssign(&n.Uint8, value)
}
// Value implements the driver Valuer interface.
func (n NullUint8) Value() (driver.Value, error) {
if !n.Valid {
return nil, nil
}
return int64(n.Uint8), nil
}