Merge pull request #789 from devlights/add-unsafe-example

Author: devlights

examples/basic/unsafes/README.md

@@ -2,7 +2,8 @@
 
 このディレクトリには以下のサンプルがあります。
 
-| file             | example name  | note                                    |
-| ---------------- | ------------- | --------------------------------------- |
-| unsafe_sizeof.go | unsafe_sizeof | unsafe.Sizeof() についてのサンプルです. |
-
+| file                 | example name      | note                                    |
+| -------------------- | ----------------- | --------------------------------------- |
+| unsafe_sizeof.go     | unsafe_sizeof     | unsafe.Sizeof() についてのサンプルです. |
+| unsafe_string.go     | unsafe_string     | unsafe.String() のサンプルです.         |
+| unsafe_stringdata.go | unsafe_stringdata | unsafe.StringData() のサンプルです.     |

examples/basic/unsafes/examples.go

@@ -14,4 +14,6 @@ func NewRegister() mapping.Register {
 // Regist -- 登録します.
 func (r *register) Regist(m mapping.ExampleMapping) {
 	m["unsafe_sizeof"] = Sizeof
+	m["unsafe_string"] = UnsafeString
+	m["unsafe_stringdata"] = UnsafeStringData
 }

examples/basic/unsafes/unsafe_string.go

@@ -0,0 +1,57 @@
+package unsafes
+
+import (
+	"syscall"
+	"unsafe"
+
+	"github.com/devlights/gomy/output"
+)
+
+// UnsafeString は、unsafe.String() のサンプルです.
+//
+// # REFERENCES
+//
+//   - https://pkg.go.dev/unsafe@go1.22.2#String
+//   - https://mattn.kaoriya.net/software/lang/go/20220907112622.htm
+func UnsafeString() error {
+	const str = "hello world"
+
+	//
+	// *byte を作成
+	//
+	var (
+		buf *byte
+		err error
+	)
+
+	buf, err = syscall.BytePtrFromString(str)
+	if err != nil {
+		return err
+	}
+
+	//
+	// unsafe.String() で、Goのstring型に変換
+	//
+	str2 := unsafe.String(buf, len(str))
+
+	output.Stdoutl("[str ]", str)
+	output.Stdoutl("[str2]", str2)
+
+	return nil
+
+	/*
+	   $ task
+	   task: [build] go build .
+	   task: [run] ./try-golang -onetime
+
+	   ENTER EXAMPLE NAME: unsafe_string
+
+	   [Name] "unsafe_string"
+	   [str ]               hello world
+	   [str2]               hello world
+
+
+	   [Elapsed] 12.471µs
+	*/
+
+}

examples/basic/unsafes/unsafe_stringdata.go

@@ -0,0 +1,38 @@
+package unsafes
+
+import (
+	"unsafe"
+
+	"github.com/devlights/gomy/output"
+)
+
+// UnsafeStringData は、unsafe.StringData() のサンプルです.
+//
+// # REFERENCES
+//   - https://pkg.go.dev/unsafe@go1.22.2#StringData
+//   - https://mattn.kaoriya.net/software/lang/go/20220907112622.htm
+func UnsafeStringData() error {
+	const str = "hello world"
+
+	buf := unsafe.StringData(str)
+	str2 := unsafe.String(buf, len(str))
+
+	output.Stdoutl("[str2]", str2)
+
+	return nil
+
+	/*
+	   $ task
+	   task: [build] go build .
+	   task: [run] ./try-golang -onetime
+
+	   ENTER EXAMPLE NAME: unsafe_stringdata
+
+	   [Name] "unsafe_stringdata"
+	   [str2]               hello world
+
+
+	   [Elapsed] 10.99µs
+	*/
+
+}