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int.go
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int.go
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package zero
import (
"database/sql"
"encoding/json"
"fmt"
"reflect"
"strconv"
)
// Int is a nullable int64.
// JSON marshals to zero if null.
// Considered null to SQL if zero.
type Int struct {
sql.NullInt64
}
// NewInt creates a new Int
func NewInt(i int64, valid bool) Int {
return Int{
NullInt64: sql.NullInt64{
Int64: i,
Valid: valid,
},
}
}
// IntFrom creates a new Int that will be null if zero.
func IntFrom(i int64) Int {
return NewInt(i, i != 0)
}
// IntFromPtr creates a new Int that be null if i is nil.
func IntFromPtr(i *int64) Int {
if i == nil {
return NewInt(0, false)
}
n := NewInt(*i, true)
return n
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will be considered a null Int.
// It also supports unmarshalling a sql.NullInt64.
func (i *Int) UnmarshalJSON(data []byte) error {
var err error
var v interface{}
if err = json.Unmarshal(data, &v); err != nil {
return err
}
switch x := v.(type) {
case float64:
// Unmarshal again, directly to int64, to avoid intermediate float64
err = json.Unmarshal(data, &i.Int64)
case string:
str := string(x)
if len(str) == 0 {
i.Valid = false
return nil
}
i.Int64, err = strconv.ParseInt(str, 10, 64)
case map[string]interface{}:
err = json.Unmarshal(data, &i.NullInt64)
case nil:
i.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type zero.Int", reflect.TypeOf(v).Name())
}
i.Valid = (err == nil) && (i.Int64 != 0)
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Int if the input is a blank, zero, or not an integer.
// It will return an error if the input is not an integer, blank, or "null".
func (i *Int) UnmarshalText(text []byte) error {
str := string(text)
if str == "" || str == "null" {
i.Valid = false
return nil
}
var err error
i.Int64, err = strconv.ParseInt(string(text), 10, 64)
i.Valid = (err == nil) && (i.Int64 != 0)
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode 0 if this Int is null.
func (i Int) MarshalJSON() ([]byte, error) {
n := i.Int64
if !i.Valid {
n = 0
}
return []byte(strconv.FormatInt(n, 10)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a zero if this Int is null.
func (i Int) MarshalText() ([]byte, error) {
n := i.Int64
if !i.Valid {
n = 0
}
return []byte(strconv.FormatInt(n, 10)), nil
}
// SetValid changes this Int's value and also sets it to be non-null.
func (i *Int) SetValid(n int64) {
i.Int64 = n
i.Valid = true
}
// Ptr returns a pointer to this Int's value, or a nil pointer if this Int is null.
func (i Int) Ptr() *int64 {
if !i.Valid {
return nil
}
return &i.Int64
}
// IsZero returns true for null or zero Ints, for future omitempty support (Go 1.4?)
func (i Int) IsZero() bool {
return !i.Valid || i.Int64 == 0
}