example_test.go

Documentation: compress/gzip

     1  // Copyright 2016 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 gzip_test
     6  
     7  import (
     8  	"bytes"
     9  	"compress/gzip"
    10  	"fmt"
    11  	"io"
    12  	"log"
    13  	"os"
    14  	"time"
    15  )
    16  
    17  func Example_writerReader() {
    18  	var buf bytes.Buffer
    19  	zw := gzip.NewWriter(&buf)
    20  
    21  	// Setting the Header fields is optional.
    22  	zw.Name = "a-new-hope.txt"
    23  	zw.Comment = "an epic space opera by George Lucas"
    24  	zw.ModTime = time.Date(1977, time.May, 25, 0, 0, 0, 0, time.UTC)
    25  
    26  	_, err := zw.Write([]byte("A long time ago in a galaxy far, far away..."))
    27  	if err != nil {
    28  		log.Fatal(err)
    29  	}
    30  
    31  	if err := zw.Close(); err != nil {
    32  		log.Fatal(err)
    33  	}
    34  
    35  	zr, err := gzip.NewReader(&buf)
    36  	if err != nil {
    37  		log.Fatal(err)
    38  	}
    39  
    40  	fmt.Printf("Name: %s\nComment: %s\nModTime: %s\n\n", zr.Name, zr.Comment, zr.ModTime.UTC())
    41  
    42  	if _, err := io.Copy(os.Stdout, zr); err != nil {
    43  		log.Fatal(err)
    44  	}
    45  
    46  	if err := zr.Close(); err != nil {
    47  		log.Fatal(err)
    48  	}
    49  
    50  	// Output:
    51  	// Name: a-new-hope.txt
    52  	// Comment: an epic space opera by George Lucas
    53  	// ModTime: 1977-05-25 00:00:00 +0000 UTC
    54  	//
    55  	// A long time ago in a galaxy far, far away...
    56  }
    57  
    58  func ExampleReader_Multistream() {
    59  	var buf bytes.Buffer
    60  	zw := gzip.NewWriter(&buf)
    61  
    62  	var files = []struct {
    63  		name    string
    64  		comment string
    65  		modTime time.Time
    66  		data    string
    67  	}{
    68  		{"file-1.txt", "file-header-1", time.Date(2006, time.February, 1, 3, 4, 5, 0, time.UTC), "Hello Gophers - 1"},
    69  		{"file-2.txt", "file-header-2", time.Date(2007, time.March, 2, 4, 5, 6, 1, time.UTC), "Hello Gophers - 2"},
    70  	}
    71  
    72  	for _, file := range files {
    73  		zw.Name = file.name
    74  		zw.Comment = file.comment
    75  		zw.ModTime = file.modTime
    76  
    77  		if _, err := zw.Write([]byte(file.data)); err != nil {
    78  			log.Fatal(err)
    79  		}
    80  
    81  		if err := zw.Close(); err != nil {
    82  			log.Fatal(err)
    83  		}
    84  
    85  		zw.Reset(&buf)
    86  	}
    87  
    88  	zr, err := gzip.NewReader(&buf)
    89  	if err != nil {
    90  		log.Fatal(err)
    91  	}
    92  
    93  	for {
    94  		zr.Multistream(false)
    95  		fmt.Printf("Name: %s\nComment: %s\nModTime: %s\n\n", zr.Name, zr.Comment, zr.ModTime.UTC())
    96  
    97  		if _, err := io.Copy(os.Stdout, zr); err != nil {
    98  			log.Fatal(err)
    99  		}
   100  
   101  		fmt.Print("\n\n")
   102  
   103  		err = zr.Reset(&buf)
   104  		if err == io.EOF {
   105  			break
   106  		}
   107  		if err != nil {
   108  			log.Fatal(err)
   109  		}
   110  	}
   111  
   112  	if err := zr.Close(); err != nil {
   113  		log.Fatal(err)
   114  	}
   115  
   116  	// Output:
   117  	// Name: file-1.txt
   118  	// Comment: file-header-1
   119  	// ModTime: 2006-02-01 03:04:05 +0000 UTC
   120  	//
   121  	// Hello Gophers - 1
   122  	//
   123  	// Name: file-2.txt
   124  	// Comment: file-header-2
   125  	// ModTime: 2007-03-02 04:05:06 +0000 UTC
   126  	//
   127  	// Hello Gophers - 2
   128  }
   129
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