reader_test.go

Documentation: compress/zlib

     1  // Copyright 2009 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 zlib
     6  
     7  import (
     8  	"bytes"
     9  	"io"
    10  	"testing"
    11  )
    12  
    13  type zlibTest struct {
    14  	desc       string
    15  	raw        string
    16  	compressed []byte
    17  	dict       []byte
    18  	err        error
    19  }
    20  
    21  // Compare-to-golden test data was generated by the ZLIB example program at
    22  // https://www.zlib.net/zpipe.c
    23  
    24  var zlibTests = []zlibTest{
    25  	{
    26  		"truncated empty",
    27  		"",
    28  		[]byte{},
    29  		nil,
    30  		io.ErrUnexpectedEOF,
    31  	},
    32  	{
    33  		"truncated dict",
    34  		"",
    35  		[]byte{0x78, 0xbb},
    36  		[]byte{0x00},
    37  		io.ErrUnexpectedEOF,
    38  	},
    39  	{
    40  		"truncated checksum",
    41  		"",
    42  		[]byte{0x78, 0xbb, 0x00, 0x01, 0x00, 0x01, 0xca, 0x48,
    43  			0xcd, 0xc9, 0xc9, 0xd7, 0x51, 0x28, 0xcf, 0x2f,
    44  			0xca, 0x49, 0x01, 0x04, 0x00, 0x00, 0xff, 0xff,
    45  		},
    46  		[]byte{0x00},
    47  		io.ErrUnexpectedEOF,
    48  	},
    49  	{
    50  		"empty",
    51  		"",
    52  		[]byte{0x78, 0x9c, 0x03, 0x00, 0x00, 0x00, 0x00, 0x01},
    53  		nil,
    54  		nil,
    55  	},
    56  	{
    57  		"goodbye",
    58  		"goodbye, world",
    59  		[]byte{
    60  			0x78, 0x9c, 0x4b, 0xcf, 0xcf, 0x4f, 0x49, 0xaa,
    61  			0x4c, 0xd5, 0x51, 0x28, 0xcf, 0x2f, 0xca, 0x49,
    62  			0x01, 0x00, 0x28, 0xa5, 0x05, 0x5e,
    63  		},
    64  		nil,
    65  		nil,
    66  	},
    67  	{
    68  		"bad header",
    69  		"",
    70  		[]byte{0x78, 0x9f, 0x03, 0x00, 0x00, 0x00, 0x00, 0x01},
    71  		nil,
    72  		ErrHeader,
    73  	},
    74  	{
    75  		"bad checksum",
    76  		"",
    77  		[]byte{0x78, 0x9c, 0x03, 0x00, 0x00, 0x00, 0x00, 0xff},
    78  		nil,
    79  		ErrChecksum,
    80  	},
    81  	{
    82  		"not enough data",
    83  		"",
    84  		[]byte{0x78, 0x9c, 0x03, 0x00, 0x00, 0x00},
    85  		nil,
    86  		io.ErrUnexpectedEOF,
    87  	},
    88  	{
    89  		"excess data is silently ignored",
    90  		"",
    91  		[]byte{
    92  			0x78, 0x9c, 0x03, 0x00, 0x00, 0x00, 0x00, 0x01,
    93  			0x78, 0x9c, 0xff,
    94  		},
    95  		nil,
    96  		nil,
    97  	},
    98  	{
    99  		"dictionary",
   100  		"Hello, World!\n",
   101  		[]byte{
   102  			0x78, 0xbb, 0x1c, 0x32, 0x04, 0x27, 0xf3, 0x00,
   103  			0xb1, 0x75, 0x20, 0x1c, 0x45, 0x2e, 0x00, 0x24,
   104  			0x12, 0x04, 0x74,
   105  		},
   106  		[]byte{
   107  			0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x57, 0x6f, 0x72, 0x6c, 0x64, 0x0a,
   108  		},
   109  		nil,
   110  	},
   111  	{
   112  		"wrong dictionary",
   113  		"",
   114  		[]byte{
   115  			0x78, 0xbb, 0x1c, 0x32, 0x04, 0x27, 0xf3, 0x00,
   116  			0xb1, 0x75, 0x20, 0x1c, 0x45, 0x2e, 0x00, 0x24,
   117  			0x12, 0x04, 0x74,
   118  		},
   119  		[]byte{
   120  			0x48, 0x65, 0x6c, 0x6c,
   121  		},
   122  		ErrDictionary,
   123  	},
   124  	{
   125  		"truncated zlib stream amid raw-block",
   126  		"hello",
   127  		[]byte{
   128  			0x78, 0x9c, 0x00, 0x0c, 0x00, 0xf3, 0xff, 0x68, 0x65, 0x6c, 0x6c, 0x6f,
   129  		},
   130  		nil,
   131  		io.ErrUnexpectedEOF,
   132  	},
   133  	{
   134  		"truncated zlib stream amid fixed-block",
   135  		"He",
   136  		[]byte{
   137  			0x78, 0x9c, 0xf2, 0x48, 0xcd,
   138  		},
   139  		nil,
   140  		io.ErrUnexpectedEOF,
   141  	},
   142  }
   143  
   144  func TestDecompressor(t *testing.T) {
   145  	b := new(bytes.Buffer)
   146  	for _, tt := range zlibTests {
   147  		in := bytes.NewReader(tt.compressed)
   148  		zr, err := NewReaderDict(in, tt.dict)
   149  		if err != nil {
   150  			if err != tt.err {
   151  				t.Errorf("%s: NewReader: %s", tt.desc, err)
   152  			}
   153  			continue
   154  		}
   155  		defer zr.Close()
   156  
   157  		// Read and verify correctness of data.
   158  		b.Reset()
   159  		n, err := io.Copy(b, zr)
   160  		if err != nil {
   161  			if err != tt.err {
   162  				t.Errorf("%s: io.Copy: %v want %v", tt.desc, err, tt.err)
   163  			}
   164  			continue
   165  		}
   166  		s := b.String()
   167  		if s != tt.raw {
   168  			t.Errorf("%s: got %d-byte %q want %d-byte %q", tt.desc, n, s, len(tt.raw), tt.raw)
   169  		}
   170  
   171  		// Check for sticky errors.
   172  		if n, err := zr.Read([]byte{0}); n != 0 || err != io.EOF {
   173  			t.Errorf("%s: Read() = (%d, %v), want (0, io.EOF)", tt.desc, n, err)
   174  		}
   175  		if err := zr.Close(); err != nil {
   176  			t.Errorf("%s: Close() = %v, want nil", tt.desc, err)
   177  		}
   178  	}
   179  }
   180
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