libgo/go/bytes/example_test.go

   1 // Copyright 2011 The Go Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style
   3 // license that can be found in the LICENSE file.
   4
   5 package bytes_test
   6
   7 import (
   8         "bytes"
   9         "encoding/base64"
  10         "fmt"
  11         "io"
  12         "os"
  13         "sort"
  14 )
  15
  16 func ExampleBuffer() {
  17         var b bytes.Buffer // A Buffer needs no initialization.
  18         b.Write([]byte("Hello "))
  19         fmt.Fprintf(&b, "world!")
  20         b.WriteTo(os.Stdout)
  21         // Output: Hello world!
  22 }
  23
  24 func ExampleBuffer_reader() {
  25         // A Buffer can turn a string or a []byte into an io.Reader.
  26         buf := bytes.NewBufferString("R29waGVycyBydWxlIQ==")
  27         dec := base64.NewDecoder(base64.StdEncoding, buf)
  28         io.Copy(os.Stdout, dec)
  29         // Output: Gophers rule!
  30 }
  31
  32 func ExampleCompare() {
  33         // Interpret Compare's result by comparing it to zero.
  34         var a, b []byte
  35         if bytes.Compare(a, b) < 0 {
  36                 // a less b
  37         }
  38         if bytes.Compare(a, b) <= 0 {
  39                 // a less or equal b
  40         }
  41         if bytes.Compare(a, b) > 0 {
  42                 // a greater b
  43         }
  44         if bytes.Compare(a, b) >= 0 {
  45                 // a greater or equal b
  46         }
  47
  48         // Prefer Equal to Compare for equality comparisons.
  49         if bytes.Equal(a, b) {
  50                 // a equal b
  51         }
  52         if !bytes.Equal(a, b) {
  53                 // a not equal b
  54         }
  55 }
  56
  57 func ExampleCompare_search() {
  58         // Binary search to find a matching byte slice.
  59         var needle []byte
  60         var haystack [][]byte // Assume sorted
  61         i := sort.Search(len(haystack), func(i int) bool {
  62                 // Return haystack[i] >= needle.
  63                 return bytes.Compare(haystack[i], needle) >= 0
  64         })
  65         if i < len(haystack) && bytes.Equal(haystack[i], needle) {
  66                 // Found it!
  67         }
  68 }
  69
  70 func ExampleTrimSuffix() {
  71         var b = []byte("Hello, goodbye, etc!")
  72         b = bytes.TrimSuffix(b, []byte("goodbye, etc!"))
  73         b = bytes.TrimSuffix(b, []byte("gopher"))
  74         b = append(b, bytes.TrimSuffix([]byte("world!"), []byte("x!"))...)
  75         os.Stdout.Write(b)
  76         // Output: Hello, world!
  77 }
  78
  79 func ExampleTrimPrefix() {
  80         var b = []byte("Goodbye,, world!")
  81         b = bytes.TrimPrefix(b, []byte("Goodbye,"))
  82         b = bytes.TrimPrefix(b, []byte("See ya,"))
  83         fmt.Printf("Hello%s", b)
  84         // Output: Hello, world!
  85 }