| // 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" |
| "io/ioutil" |
| "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, 5); err != nil { |
| log.Fatal(err) |
| } |
| |
| // Output: |
| // some |
| } |
| |
| func ExampleReadAtLeast() { |
| r := strings.NewReader("some io.Reader stream to be read\n") |
| |
| buf := make([]byte, 33) |
| 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 stream to be read |
| // |
| // error: short buffer |
| // error: 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() { |
| r := strings.NewReader("some io.Reader stream to be read\n") |
| var buf bytes.Buffer |
| tee := io.TeeReader(r, &buf) |
| |
| printall := func(r io.Reader) { |
| b, err := ioutil.ReadAll(r) |
| if err != nil { |
| log.Fatal(err) |
| } |
| |
| fmt.Printf("%s", b) |
| } |
| |
| printall(tee) |
| printall(&buf) |
| |
| // Output: |
| // some io.Reader stream to be read |
| // 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, 16) |
| |
| 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, 16) |
| |
| if _, err := s.Seek(10, io.SeekStart); err != nil { |
| log.Fatal(err) |
| } |
| |
| buf := make([]byte, 6) |
| if _, err := s.Read(buf); err != nil { |
| log.Fatal(err) |
| } |
| |
| fmt.Printf("%s\n", buf) |
| |
| // Output: |
| // stream |
| } |
| |
| func ExampleSeeker_Seek() { |
| r := strings.NewReader("some io.Reader stream to be read\n") |
| if _, err := io.Copy(os.Stdout, r); err != nil { |
| log.Fatal(err) |
| } |
| |
| r.Seek(15, io.SeekStart) |
| 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: |
| // some io.Reader stream to be read |
| // 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 |
| } |