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package zero
import (
"database/sql"
"encoding/json"
"fmt"
"reflect"
"strconv"
)
// Float is a nullable float64. Zero input will be considered null.
// JSON marshals to zero if null.
// Considered null to SQL if zero.
type Float struct {
sql.NullFloat64
}
// NewFloat creates a new Float
func NewFloat(f float64, valid bool) Float {
return Float{
NullFloat64: sql.NullFloat64{
Float64: f,
Valid: valid,
},
}
}
// FloatFrom creates a new Float that will be null if zero.
func FloatFrom(f float64) Float {
return NewFloat(f, f != 0)
}
// FloatFromPtr creates a new Float that be null if f is nil.
func FloatFromPtr(f *float64) Float {
if f == nil {
return NewFloat(0, false)
}
return NewFloat(*f, true)
}
// UnmarshalJSON implements json.Unmarshaler.
// It supports number and null input.
// 0 will be considered a null Float.
// It also supports unmarshalling a sql.NullFloat64.
func (f *Float) 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 = 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 zero.Float", reflect.TypeOf(v).Name())
}
f.Valid = (err == nil) && (f.Float64 != 0)
return err
}
// UnmarshalText implements encoding.TextUnmarshaler.
// It will unmarshal to a null Float if the input is a blank, zero, or not a float.
// It will return an error if the input is not a float, blank, or "null".
func (f *Float) 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) && (f.Float64 != 0)
return err
}
// MarshalJSON implements json.Marshaler.
// It will encode null if this Float is null.
func (f Float) MarshalJSON() ([]byte, error) {
n := f.Float64
if !f.Valid {
n = 0
}
return []byte(strconv.FormatFloat(n, 'f', -1, 64)), nil
}
// MarshalText implements encoding.TextMarshaler.
// It will encode a zero if this Float is null.
func (f Float) MarshalText() ([]byte, error) {
n := f.Float64
if !f.Valid {
n = 0
}
return []byte(strconv.FormatFloat(n, 'f', -1, 64)), nil
}
// SetValid changes this Float's value and also sets it to be non-null.
func (f *Float) SetValid(v float64) {
f.Float64 = v
f.Valid = true
}
// Ptr returns a poFloater to this Float's value, or a nil poFloater if this Float is null.
func (f Float) Ptr() *float64 {
if !f.Valid {
return nil
}
return &f.Float64
}
// IsZero returns true for null or zero Floats, for future omitempty support (Go 1.4?)
func (f Float) IsZero() bool {
return !f.Valid || f.Float64 == 0
}
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