Files
bt/bencode/iszero_go1.12.go
2023-05-14 19:19:52 +00:00

64 lines
1.8 KiB
Go

// Copyright 2020 xgfone, 2023 idk
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
//go:build !go1.13
// +build !go1.13
package bencode
import (
"math"
"reflect"
)
func isZero(v reflect.Value) bool {
switch v.Kind() {
case reflect.Bool:
return !v.Bool()
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:
c := v.Complex()
return math.Float64bits(real(c)) == 0 && math.Float64bits(imag(c)) == 0
case reflect.Array:
for i := 0; i < v.Len(); i++ {
if !isZero(v.Index(i)) {
return false
}
}
return true
case reflect.Chan, reflect.Func, reflect.Interface, reflect.Map,
reflect.Ptr, reflect.Slice, reflect.UnsafePointer:
return v.IsNil()
case reflect.String:
return v.Len() == 0
case reflect.Struct:
for i := 0; i < v.NumField(); i++ {
if !isZero(v.Field(i)) {
return false
}
}
return true
default:
// This should never happens, but will act as a safeguard for
// later, as a default value doesn't makes sense here.
panic(&reflect.ValueError{Method: "reflect.Value.IsZero", Kind: v.Kind()})
}
}