From 754c23a560f3d7aa194863fe0bcdab0001a19d13 Mon Sep 17 00:00:00 2001
From: Fedor Korotkiy <prime@yandex-team.ru>
Date: Wed, 14 Apr 2021 18:41:01 +0300
Subject: [PATCH] Add illegal task

---
 illegal/README.md          |  6 ++++++
 illegal/field.go           |  6 ++++++
 illegal/field_test.go      | 18 ++++++++++++++++++
 illegal/internal/struct.go | 14 ++++++++++++++
 illegal/string.go          |  7 +++++++
 illegal/string_test.go     | 17 +++++++++++++++++
 6 files changed, 68 insertions(+)
 create mode 100644 illegal/README.md
 create mode 100644 illegal/field.go
 create mode 100644 illegal/field_test.go
 create mode 100644 illegal/internal/struct.go
 create mode 100644 illegal/string.go
 create mode 100644 illegal/string_test.go

diff --git a/illegal/README.md b/illegal/README.md
new file mode 100644
index 0000000..4940565
--- /dev/null
+++ b/illegal/README.md
@@ -0,0 +1,6 @@
+# illegal
+
+Используя пакет unsafe, реализуйте "незаконные" функции:
+
+- `SetPrivateField` меняет приватное поле структуры
+- `StringFromBytes` создаёт строку из `[]byte` без доп. аллокаций
diff --git a/illegal/field.go b/illegal/field.go
new file mode 100644
index 0000000..daf0040
--- /dev/null
+++ b/illegal/field.go
@@ -0,0 +1,6 @@
+// +build !solution
+
+package illegal
+
+func SetPrivateField(obj interface{}, name string, value interface{}) {
+}
diff --git a/illegal/field_test.go b/illegal/field_test.go
new file mode 100644
index 0000000..d542de1
--- /dev/null
+++ b/illegal/field_test.go
@@ -0,0 +1,18 @@
+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())
+}
diff --git a/illegal/internal/struct.go b/illegal/internal/struct.go
new file mode 100644
index 0000000..4bfe525
--- /dev/null
+++ b/illegal/internal/struct.go
@@ -0,0 +1,14 @@
+// +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)
+}
diff --git a/illegal/string.go b/illegal/string.go
new file mode 100644
index 0000000..92451ba
--- /dev/null
+++ b/illegal/string.go
@@ -0,0 +1,7 @@
+// +build !solution
+
+package illegal
+
+func StringFromBytes(b []byte) string {
+	panic("implement me")
+}
diff --git a/illegal/string_test.go b/illegal/string_test.go
new file mode 100644
index 0000000..bfd1014
--- /dev/null
+++ b/illegal/string_test.go
@@ -0,0 +1,17 @@
+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)))
+}