49 lines
1.3 KiB
Go
49 lines
1.3 KiB
Go
|
// Copyright 2017, The Go Authors. All rights reserved.
|
||
|
|
// Use of this source code is governed by a BSD-style
|
||
|
|
// license that can be found in the LICENSE.md file.
|
||
|
|
|
||
|
|
package value
|
||
|
|
|
||
|
|
import (
|
||
|
|
"math"
|
||
|
|
"reflect"
|
||
|
|
)
|
||
|
|
|
||
|
|
// IsZero reports whether v is the zero value.
|
||
|
|
// This does not rely on Interface and so can be used on unexported fields.
|
||
|
|
func IsZero(v reflect.Value) bool {
|
||
|
|
switch v.Kind() {
|
||
|
|
case reflect.Bool:
|
||
|
|
return v.Bool() == false
|
||
|
|
case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
|
||
|
|
return v.Int() == 0
|
||
|
|
case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr:
|
||
|
|
return v.Uint() == 0
|
||
|
|
case reflect.Float32, reflect.Float64:
|
||
|
|
return math.Float64bits(v.Float()) == 0
|
||
|
|
case reflect.Complex64, reflect.Complex128:
|
||
|
|
return math.Float64bits(real(v.Complex())) == 0 && math.Float64bits(imag(v.Complex())) == 0
|
||
|
|
case reflect.String:
|
||
|
|
return v.String() == ""
|
||
|
|
case reflect.UnsafePointer:
|
||
|
|
return v.Pointer() == 0
|
||
|
|
case reflect.Chan, reflect.Func, reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice:
|
||
|
|
return v.IsNil()
|
||
|
|
case reflect.Array:
|
||
|
|
for i := 0; i < v.Len(); i++ {
|
||
|
|
if !IsZero(v.Index(i)) {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return true
|
||
|
|
case reflect.Struct:
|
||
|
|
for i := 0; i < v.NumField(); i++ {
|
||
|
|
if !IsZero(v.Field(i)) {
|
||
|
|
return false
|
||
|
|
}
|
||
|
|
}
|
||
|
|
return true
|
||
|
|
}
|
||
|
|
return false
|
||
|
|
}
|