| // 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 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 |
| } |