Pragya Arya | 324337e | 2020-02-20 14:35:08 +0530 | [diff] [blame] | 1 | // Copyright 2017, The Go Authors. All rights reserved. |
| 2 | // Use of this source code is governed by a BSD-style |
| 3 | // license that can be found in the LICENSE.md file. |
| 4 | |
| 5 | package value |
| 6 | |
| 7 | import ( |
| 8 | "math" |
| 9 | "reflect" |
| 10 | ) |
| 11 | |
| 12 | // IsZero reports whether v is the zero value. |
| 13 | // This does not rely on Interface and so can be used on unexported fields. |
| 14 | func IsZero(v reflect.Value) bool { |
| 15 | switch v.Kind() { |
| 16 | case reflect.Bool: |
| 17 | return v.Bool() == false |
| 18 | case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64: |
| 19 | return v.Int() == 0 |
| 20 | case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64, reflect.Uintptr: |
| 21 | return v.Uint() == 0 |
| 22 | case reflect.Float32, reflect.Float64: |
| 23 | return math.Float64bits(v.Float()) == 0 |
| 24 | case reflect.Complex64, reflect.Complex128: |
| 25 | return math.Float64bits(real(v.Complex())) == 0 && math.Float64bits(imag(v.Complex())) == 0 |
| 26 | case reflect.String: |
| 27 | return v.String() == "" |
| 28 | case reflect.UnsafePointer: |
| 29 | return v.Pointer() == 0 |
| 30 | case reflect.Chan, reflect.Func, reflect.Interface, reflect.Ptr, reflect.Map, reflect.Slice: |
| 31 | return v.IsNil() |
| 32 | case reflect.Array: |
| 33 | for i := 0; i < v.Len(); i++ { |
| 34 | if !IsZero(v.Index(i)) { |
| 35 | return false |
| 36 | } |
| 37 | } |
| 38 | return true |
| 39 | case reflect.Struct: |
| 40 | for i := 0; i < v.NumField(); i++ { |
| 41 | if !IsZero(v.Field(i)) { |
| 42 | return false |
| 43 | } |
| 44 | } |
| 45 | return true |
| 46 | } |
| 47 | return false |
| 48 | } |