Add illegal task

This commit is contained in:
Fedor Korotkiy 2021-04-14 18:41:01 +03:00
parent 8c0112889f
commit 754c23a560
6 changed files with 68 additions and 0 deletions

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illegal/README.md Normal file
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# illegal
Используя пакет unsafe, реализуйте "незаконные" функции:
- `SetPrivateField` меняет приватное поле структуры
- `StringFromBytes` создаёт строку из `[]byte` без доп. аллокаций

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illegal/field.go Normal file
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// +build !solution
package illegal
func SetPrivateField(obj interface{}, name string, value interface{}) {
}

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illegal/field_test.go Normal file
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package illegal_test
import (
"testing"
"github.com/stretchr/testify/assert"
"gitlab.com/slon/shad-go/illegal"
"gitlab.com/slon/shad-go/illegal/internal"
)
func TestIllegalField(t *testing.T) {
var s internal.Struct
illegal.SetPrivateField(&s, "a", 10)
illegal.SetPrivateField(&s, "b", "foo")
assert.Equal(t, "10 foo", s.String())
}

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// +build !change
package internal
import "fmt"
type Struct struct {
a int
b string
}
func (s *Struct) String() string {
return fmt.Sprintf("%d %s", s.a, s.b)
}

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illegal/string.go Normal file
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// +build !solution
package illegal
func StringFromBytes(b []byte) string {
panic("implement me")
}

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illegal/string_test.go Normal file
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package illegal_test
import (
"testing"
"unsafe"
"github.com/stretchr/testify/assert"
"gitlab.com/slon/shad-go/illegal"
)
func TestStringFromBytes(t *testing.T) {
b := []byte{'a', 'b', 'c'}
s := illegal.StringFromBytes(b)
assert.Equal(t, "abc", s)
assert.Equal(t, **(**uintptr)(unsafe.Pointer(&b)), **(**uintptr)(unsafe.Pointer(&s)))
}