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unsafe_go1.17.go
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unsafe_go1.17.go
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//go:build go1.17
// +build go1.17
// Package unsafe provides wrapper of standard library unsafe package to be imported natively in Yaegi.
package unsafe
import (
"errors"
"reflect"
"unsafe"
)
func init() {
// Add builtin functions to unsafe.
Symbols["unsafe/unsafe"]["Add"] = reflect.ValueOf(add)
Symbols["unsafe/unsafe"]["Slice"] = reflect.ValueOf(slice)
}
func add(ptr unsafe.Pointer, l int) unsafe.Pointer {
return unsafe.Pointer(uintptr(ptr) + uintptr(l))
}
type emptyInterface struct {
_ uintptr
data unsafe.Pointer
}
func slice(i interface{}, l int) interface{} {
if l == 0 {
return nil
}
v := reflect.ValueOf(i)
if v.Kind() != reflect.Ptr {
panic(errors.New("first argument to unsafe.Slice must be pointer"))
}
if v.IsNil() {
panic(errors.New("unsafe.Slice: ptr is nil and len is not zero"))
}
if l < 0 {
panic(errors.New("unsafe.Slice: len out of range"))
}
ih := *(*emptyInterface)(unsafe.Pointer(&i))
inter := reflect.MakeSlice(reflect.SliceOf(v.Type().Elem()), l, l).Interface()
ptr := (*emptyInterface)(unsafe.Pointer(&inter)).data
sh := (*reflect.SliceHeader)(ptr)
sh.Data = uintptr(ih.data)
sh.Len = l
sh.Cap = l
return inter
}