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