有没有一种在Go语言中使用unsafe.Pointer实现整数转换函数的方法？

huangapple
go评论112阅读模式
英文:

Is there a way to implement this integer casting function with unsafe Pointer in golang?

问题

我在想是否可以实现一个更简洁的函数版本，并且性能更好会很棒。

  1. func AnyIntToInt(x interface{}) (int, error) {
  2. 	switch val := x.(type) {
  3. 	case int8:
  4. 		return int(val), nil
  5. 	case int16:
  6. 		return int(val), nil
  7. 	case int32:
  8. 		return int(val), nil
  9. 	case int64:
  10. 		return int(val), nil
  11. 	case uint8:
  12. 		return int(val), nil
  13. 	case uint16:
  14. 		return int(val), nil
  15. 	case uint32:
  16. 		return int(val), nil
  17. 	case uint64:
  18. 		return int(val), nil
  19. 	}
  20. 	return 0, ErrNotInteger
  21. }

我尝试了下面这个版本，但是它产生了意外的结果。

  1. func AnyIntToInt(x interface{}) (int, error) {
  2. 	return *(*int)(unsafe.Pointer(&x))
  3. }
英文:

I was wondering if I could implement a less verbose version of this function. It would be great if it had better performance.

  1. func AnyIntToInt(x interface{}) (int, error) {
  2. 	switch val := x.(type) {
  3. 	case int8:
  4. 		return int(val), nil
  5. 	case int16:
  6. 		return int(val), nil
  7. 	case int32:
  8. 		return int(val), nil
  9. 	case int64:
  10. 		return int(val), nil
  11. 	case uint8:
  12. 		return int(val), nil
  13. 	case uint16:
  14. 		return int(val), nil
  15. 	case uint32:
  16. 		return int(val), nil
  17. 	case uint64:
  18. 		return int(val), nil
  19. 	}
  20. 	return 0, ErrNotInteger
  21. }

I have been trying with this one, however it yields unexpected results.

  1. func AnyIntToInt(x interface{}) (int, error) {
  2. 	return *(*int)(unsafe.Pointer(&x))
  3. }

答案1

得分: 1

问题中的代码是正确的方法，但是你可以使用reflect包来减少代码行数：

  1. func AnyIntToInt(x interface{}) (int, error) {
  2.     v := reflect.ValueOf(x)
  3.     switch v.Kind() {
  4.     case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
  5.         return int(v.Int()), nil
  6.     case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
  7.         return int(v.Uint()), nil
  8.     }
  9.     return 0, ErrNotInteger
  10. }

https://go.dev/play/p/gJ4ASo7AeyN

英文:

The code in the question is the way to go, but you can reduce lines of code using the reflect package:

  1. func AnyIntToInt(x interface{}) (int, error) {
  2. 	v := reflect.ValueOf(x)
  3. 	switch v.Kind() {
  4. 	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
  5. 		return int(v.Int()), nil
  6. 	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32, reflect.Uint64:
  7. 		return int(v.Uint()), nil
  8. 	}
  9. 	return 0, ErrNotInteger
  10. }

https://go.dev/play/p/gJ4ASo7AeyN

huangapple
  • 本文由 发表于 2021年12月12日 08:08:10
  • 转载请务必保留本文链接：https://go.coder-hub.com/70319995.html
  • casting
  • go
  • unsafe
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定