lbry.go/float64.go
Patrick O'brien bbb7b84bb6 Add all int and float null types
* Add Scan and Value methods for non sql.Int64 and sql.Float64 types
* Change NullInt to use int in the code opposed to int64
* Rename Float to Float64
* Add support for all missing key int and float types:
  float32, int8, int16, int32, int64, uint8, uint16, uint32, uint64

* Update README to include new additions/changes
2016-05-17 22:02:36 +10:00

117 lines
2.9 KiB
Go

package null
import (
"database/sql"
"encoding/json"
"fmt"
"reflect"
"strconv"
)
// Float64 is a nullable float64.
// It does not consider zero values to be null.
// It will decode to null, not zero, if null.
type Float64 struct {
sql.NullFloat64
}
// NewFloat64 creates a new Float64
func NewFloat64(f float64, valid bool) Float64 {
return Float64{
NullFloat64: sql.NullFloat64{
Float64: f,
Valid: valid,
},
}
}
// Float64From creates a new Float64 that will always be valid.
func Float64From(f float64) Float64 {
return NewFloat64(f, true)
}
// Float64FromPtr creates a new Float64 that be null if f is nil.
func Float64FromPtr(f *float64) Float64 {
if f == nil {
return NewFloat64(0, false)
}
return NewFloat64(*f, true)
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will not be considered a null Float64.
// It also supports unmarshalling a sql.NullFloat64.
func (f *Float64) 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:
f.Float64 = float64(x)
case map[string]interface{}:
err = json.Unmarshal(data, &f.NullFloat64)
case nil:
f.Valid = false
return nil
default:
err = fmt.Errorf("json: cannot unmarshal %v into Go value of type null.Float64", reflect.TypeOf(v).Name())
}
f.Valid = err == nil
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Float64 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 (f *Float64) UnmarshalText(text []byte) error {
str := string(text)
if str == "" || str == "null" {
f.Valid = false
return nil
}
var err error
f.Float64, err = strconv.ParseFloat(string(text), 64)
f.Valid = err == nil
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Float64 is null.
func (f Float64) MarshalJSON() ([]byte, error) {
if !f.Valid {
return []byte("null"), nil
}
return []byte(strconv.FormatFloat(f.Float64, 'f', -1, 64)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a blank string if this Float64 is null.
func (f Float64) MarshalText() ([]byte, error) {
if !f.Valid {
return []byte{}, nil
}
return []byte(strconv.FormatFloat(f.Float64, 'f', -1, 64)), nil
}
// SetValid changes this Float64's value and also sets it to be non-null.
func (f *Float64) SetValid(n float64) {
f.Float64 = n
f.Valid = true
}
// Ptr returns a pointer to this Float64's value, or a nil pointer if this Float64 is null.
func (f Float64) Ptr() *float64 {
if !f.Valid {
return nil
}
return &f.Float64
}
// IsZero returns true for invalid Float64s, for future omitempty support (Go 1.4?)
// A non-null Float64 with a 0 value will not be considered zero.
func (f Float64) IsZero() bool {
return !f.Valid
}