diff options
Diffstat (limited to 'src/pkg/compress/lzw/reader_test.go')
-rw-r--r-- | src/pkg/compress/lzw/reader_test.go | 132 |
1 files changed, 132 insertions, 0 deletions
diff --git a/src/pkg/compress/lzw/reader_test.go b/src/pkg/compress/lzw/reader_test.go new file mode 100644 index 000000000..7795a4c14 --- /dev/null +++ b/src/pkg/compress/lzw/reader_test.go @@ -0,0 +1,132 @@ +// Copyright 2011 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 lzw + +import ( + "bytes" + "io" + "io/ioutil" + "os" + "strconv" + "strings" + "testing" +) + +type lzwTest struct { + desc string + raw string + compressed string + err os.Error +} + +var lzwTests = []lzwTest{ + { + "empty;LSB;8", + "", + "\x01\x01", + nil, + }, + { + "empty;MSB;8", + "", + "\x80\x80", + nil, + }, + { + "tobe;LSB;7", + "TOBEORNOTTOBEORTOBEORNOT", + "\x54\x4f\x42\x45\x4f\x52\x4e\x4f\x54\x82\x84\x86\x8b\x85\x87\x89\x81", + nil, + }, + { + "tobe;LSB;8", + "TOBEORNOTTOBEORTOBEORNOT", + "\x54\x9e\x08\x29\xf2\x44\x8a\x93\x27\x54\x04\x12\x34\xb8\xb0\xe0\xc1\x84\x01\x01", + nil, + }, + { + "tobe;MSB;7", + "TOBEORNOTTOBEORTOBEORNOT", + "\x54\x4f\x42\x45\x4f\x52\x4e\x4f\x54\x82\x84\x86\x8b\x85\x87\x89\x81", + nil, + }, + { + "tobe;MSB;8", + "TOBEORNOTTOBEORTOBEORNOT", + "\x2a\x13\xc8\x44\x52\x79\x48\x9c\x4f\x2a\x40\xa0\x90\x68\x5c\x16\x0f\x09\x80\x80", + nil, + }, + { + "tobe-truncated;LSB;8", + "TOBEORNOTTOBEORTOBEORNOT", + "\x54\x9e\x08\x29\xf2\x44\x8a\x93\x27\x54\x04", + io.ErrUnexpectedEOF, + }, + // This example comes from http://en.wikipedia.org/wiki/Graphics_Interchange_Format. + { + "gif;LSB;8", + "\x28\xff\xff\xff\x28\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff", + "\x00\x51\xfc\x1b\x28\x70\xa0\xc1\x83\x01\x01", + nil, + }, + // This example comes from http://compgroups.net/comp.lang.ruby/Decompressing-LZW-compression-from-PDF-file + { + "pdf;MSB;8", + "-----A---B", + "\x80\x0b\x60\x50\x22\x0c\x0c\x85\x01", + nil, + }, +} + +func TestReader(t *testing.T) { + b := bytes.NewBuffer(nil) + for _, tt := range lzwTests { + d := strings.Split(tt.desc, ";", -1) + var order Order + switch d[1] { + case "LSB": + order = LSB + case "MSB": + order = MSB + default: + t.Errorf("%s: bad order %q", tt.desc, d[1]) + } + litWidth, _ := strconv.Atoi(d[2]) + rc := NewReader(strings.NewReader(tt.compressed), order, litWidth) + defer rc.Close() + b.Reset() + n, err := io.Copy(b, rc) + if err != nil { + if err != tt.err { + t.Errorf("%s: io.Copy: %v want %v", tt.desc, err, tt.err) + } + continue + } + s := b.String() + if s != tt.raw { + t.Errorf("%s: got %d-byte %q want %d-byte %q", tt.desc, n, s, len(tt.raw), tt.raw) + } + } +} + +type devNull struct{} + +func (devNull) Write(p []byte) (int, os.Error) { + return len(p), nil +} + +func BenchmarkDecoder(b *testing.B) { + b.StopTimer() + buf0, _ := ioutil.ReadFile("../testdata/e.txt") + compressed := bytes.NewBuffer(nil) + w := NewWriter(compressed, LSB, 8) + io.Copy(w, bytes.NewBuffer(buf0)) + w.Close() + buf1 := compressed.Bytes() + b.StartTimer() + for i := 0; i < b.N; i++ { + io.Copy(devNull{}, NewReader(bytes.NewBuffer(buf1), LSB, 8)) + } +} |