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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 13:14:23 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-28 13:14:23 +0000
commit73df946d56c74384511a194dd01dbe099584fd1a (patch)
treefd0bcea490dd81327ddfbb31e215439672c9a068 /src/io/example_test.go
parentInitial commit. (diff)
downloadgolang-1.16-upstream.tar.xz
golang-1.16-upstream.zip
Adding upstream version 1.16.10.upstream/1.16.10upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'src/io/example_test.go')
-rw-r--r--src/io/example_test.go256
1 files changed, 256 insertions, 0 deletions
diff --git a/src/io/example_test.go b/src/io/example_test.go
new file mode 100644
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--- /dev/null
+++ b/src/io/example_test.go
@@ -0,0 +1,256 @@
+// Copyright 2015 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 io_test
+
+import (
+ "bytes"
+ "fmt"
+ "io"
+ "log"
+ "os"
+ "strings"
+)
+
+func ExampleCopy() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+
+ if _, err := io.Copy(os.Stdout, r); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // some io.Reader stream to be read
+}
+
+func ExampleCopyBuffer() {
+ r1 := strings.NewReader("first reader\n")
+ r2 := strings.NewReader("second reader\n")
+ buf := make([]byte, 8)
+
+ // buf is used here...
+ if _, err := io.CopyBuffer(os.Stdout, r1, buf); err != nil {
+ log.Fatal(err)
+ }
+
+ // ... reused here also. No need to allocate an extra buffer.
+ if _, err := io.CopyBuffer(os.Stdout, r2, buf); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // first reader
+ // second reader
+}
+
+func ExampleCopyN() {
+ r := strings.NewReader("some io.Reader stream to be read")
+
+ if _, err := io.CopyN(os.Stdout, r, 4); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // some
+}
+
+func ExampleReadAtLeast() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+
+ buf := make([]byte, 14)
+ if _, err := io.ReadAtLeast(r, buf, 4); err != nil {
+ log.Fatal(err)
+ }
+ fmt.Printf("%s\n", buf)
+
+ // buffer smaller than minimal read size.
+ shortBuf := make([]byte, 3)
+ if _, err := io.ReadAtLeast(r, shortBuf, 4); err != nil {
+ fmt.Println("error:", err)
+ }
+
+ // minimal read size bigger than io.Reader stream
+ longBuf := make([]byte, 64)
+ if _, err := io.ReadAtLeast(r, longBuf, 64); err != nil {
+ fmt.Println("error:", err)
+ }
+
+ // Output:
+ // some io.Reader
+ // error: short buffer
+ // error: unexpected EOF
+}
+
+func ExampleReadFull() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+
+ buf := make([]byte, 4)
+ if _, err := io.ReadFull(r, buf); err != nil {
+ log.Fatal(err)
+ }
+ fmt.Printf("%s\n", buf)
+
+ // minimal read size bigger than io.Reader stream
+ longBuf := make([]byte, 64)
+ if _, err := io.ReadFull(r, longBuf); err != nil {
+ fmt.Println("error:", err)
+ }
+
+ // Output:
+ // some
+ // error: unexpected EOF
+}
+
+func ExampleWriteString() {
+ io.WriteString(os.Stdout, "Hello World")
+
+ // Output: Hello World
+}
+
+func ExampleLimitReader() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+ lr := io.LimitReader(r, 4)
+
+ if _, err := io.Copy(os.Stdout, lr); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // some
+}
+
+func ExampleMultiReader() {
+ r1 := strings.NewReader("first reader ")
+ r2 := strings.NewReader("second reader ")
+ r3 := strings.NewReader("third reader\n")
+ r := io.MultiReader(r1, r2, r3)
+
+ if _, err := io.Copy(os.Stdout, r); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // first reader second reader third reader
+}
+
+func ExampleTeeReader() {
+ var r io.Reader = strings.NewReader("some io.Reader stream to be read\n")
+
+ r = io.TeeReader(r, os.Stdout)
+
+ // Everything read from r will be copied to stdout.
+ io.ReadAll(r)
+
+ // Output:
+ // some io.Reader stream to be read
+}
+
+func ExampleSectionReader() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+ s := io.NewSectionReader(r, 5, 17)
+
+ if _, err := io.Copy(os.Stdout, s); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // io.Reader stream
+}
+
+func ExampleSectionReader_ReadAt() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+ s := io.NewSectionReader(r, 5, 17)
+
+ buf := make([]byte, 6)
+ if _, err := s.ReadAt(buf, 10); err != nil {
+ log.Fatal(err)
+ }
+
+ fmt.Printf("%s\n", buf)
+
+ // Output:
+ // stream
+}
+
+func ExampleSectionReader_Seek() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+ s := io.NewSectionReader(r, 5, 17)
+
+ if _, err := s.Seek(10, io.SeekStart); err != nil {
+ log.Fatal(err)
+ }
+
+ if _, err := io.Copy(os.Stdout, s); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // stream
+}
+
+func ExampleSeeker_Seek() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+
+ r.Seek(5, io.SeekStart) // move to the 5th char from the start
+ if _, err := io.Copy(os.Stdout, r); err != nil {
+ log.Fatal(err)
+ }
+
+ r.Seek(-5, io.SeekEnd)
+ if _, err := io.Copy(os.Stdout, r); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // io.Reader stream to be read
+ // read
+}
+
+func ExampleMultiWriter() {
+ r := strings.NewReader("some io.Reader stream to be read\n")
+
+ var buf1, buf2 bytes.Buffer
+ w := io.MultiWriter(&buf1, &buf2)
+
+ if _, err := io.Copy(w, r); err != nil {
+ log.Fatal(err)
+ }
+
+ fmt.Print(buf1.String())
+ fmt.Print(buf2.String())
+
+ // Output:
+ // some io.Reader stream to be read
+ // some io.Reader stream to be read
+}
+
+func ExamplePipe() {
+ r, w := io.Pipe()
+
+ go func() {
+ fmt.Fprint(w, "some io.Reader stream to be read\n")
+ w.Close()
+ }()
+
+ if _, err := io.Copy(os.Stdout, r); err != nil {
+ log.Fatal(err)
+ }
+
+ // Output:
+ // some io.Reader stream to be read
+}
+
+func ExampleReadAll() {
+ r := strings.NewReader("Go is a general-purpose language designed with systems programming in mind.")
+
+ b, err := io.ReadAll(r)
+ if err != nil {
+ log.Fatal(err)
+ }
+
+ fmt.Printf("%s", b)
+
+ // Output:
+ // Go is a general-purpose language designed with systems programming in mind.
+}