mirror of
https://github.com/golang/go
synced 2024-11-23 03:50:03 -07:00
51 lines
862 B
Go
51 lines
862 B
Go
|
// run
|
||
|
|
|
||
|
|
// Copyright 2023 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 main
|
||
|
|
|
||
|
|
import (
|
||
|
|
"strings"
|
||
|
|
"unsafe"
|
||
|
|
)
|
||
|
|
|
||
|
|
func shift[T any]() int64 {
|
||
|
|
return 1 << unsafe.Sizeof(*new(T))
|
||
|
|
}
|
||
|
|
|
||
|
|
func div[T any]() uintptr {
|
||
|
|
return 1 / unsafe.Sizeof(*new(T))
|
||
|
|
}
|
||
|
|
|
||
|
|
func add[T any]() int64 {
|
||
|
|
return 1<<63 - 1 + int64(unsafe.Sizeof(*new(T)))
|
||
|
|
}
|
||
|
|
|
||
|
|
func main() {
|
||
|
|
shift[[62]byte]()
|
||
|
|
shift[[63]byte]()
|
||
|
|
shift[[64]byte]()
|
||
|
|
shift[[100]byte]()
|
||
|
|
shift[[1e6]byte]()
|
||
|
|
|
||
|
|
add[[1]byte]()
|
||
|
|
shouldPanic("divide by zero", func() { div[[0]byte]() })
|
||
|
|
}
|
||
|
|
|
||
|
|
func shouldPanic(str string, f func()) {
|
||
|
|
defer func() {
|
||
|
|
err := recover()
|
||
|
|
if err == nil {
|
||
|
|
panic("did not panic")
|
||
|
|
}
|
||
|
|
s := err.(error).Error()
|
||
|
|
if !strings.Contains(s, str) {
|
||
|
|
panic("got panic " + s + ", want " + str)
|
||
|
|
}
|
||
|
|
}()
|
||
|
|
|
||
|
|
f()
|
||
|
|
}
|