mirror of
https://github.com/autc04/Retro68.git
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145 lines
2.9 KiB
Go
145 lines
2.9 KiB
Go
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// Copyright 2011 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package lzw
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import (
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"bytes"
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"io"
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"io/ioutil"
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"runtime"
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"strconv"
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"strings"
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"testing"
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)
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type lzwTest struct {
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desc string
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raw string
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compressed string
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err error
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}
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var lzwTests = []lzwTest{
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{
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"empty;LSB;8",
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"",
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"\x01\x01",
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nil,
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},
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{
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"empty;MSB;8",
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"",
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"\x80\x80",
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nil,
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},
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{
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"tobe;LSB;7",
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"TOBEORNOTTOBEORTOBEORNOT",
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"\x54\x4f\x42\x45\x4f\x52\x4e\x4f\x54\x82\x84\x86\x8b\x85\x87\x89\x81",
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nil,
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},
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{
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"tobe;LSB;8",
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"TOBEORNOTTOBEORTOBEORNOT",
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"\x54\x9e\x08\x29\xf2\x44\x8a\x93\x27\x54\x04\x12\x34\xb8\xb0\xe0\xc1\x84\x01\x01",
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nil,
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},
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{
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"tobe;MSB;7",
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"TOBEORNOTTOBEORTOBEORNOT",
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"\x54\x4f\x42\x45\x4f\x52\x4e\x4f\x54\x82\x84\x86\x8b\x85\x87\x89\x81",
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nil,
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},
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{
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"tobe;MSB;8",
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"TOBEORNOTTOBEORTOBEORNOT",
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"\x2a\x13\xc8\x44\x52\x79\x48\x9c\x4f\x2a\x40\xa0\x90\x68\x5c\x16\x0f\x09\x80\x80",
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nil,
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},
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{
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"tobe-truncated;LSB;8",
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"TOBEORNOTTOBEORTOBEORNOT",
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"\x54\x9e\x08\x29\xf2\x44\x8a\x93\x27\x54\x04",
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io.ErrUnexpectedEOF,
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},
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// This example comes from http://en.wikipedia.org/wiki/Graphics_Interchange_Format.
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{
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"gif;LSB;8",
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"\x28\xff\xff\xff\x28\xff\xff\xff\xff\xff\xff\xff\xff\xff\xff",
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"\x00\x51\xfc\x1b\x28\x70\xa0\xc1\x83\x01\x01",
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nil,
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},
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// This example comes from http://compgroups.net/comp.lang.ruby/Decompressing-LZW-compression-from-PDF-file
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{
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"pdf;MSB;8",
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"-----A---B",
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"\x80\x0b\x60\x50\x22\x0c\x0c\x85\x01",
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nil,
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},
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}
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func TestReader(t *testing.T) {
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var b bytes.Buffer
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for _, tt := range lzwTests {
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d := strings.Split(tt.desc, ";")
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var order Order
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switch d[1] {
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case "LSB":
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order = LSB
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case "MSB":
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order = MSB
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default:
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t.Errorf("%s: bad order %q", tt.desc, d[1])
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}
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litWidth, _ := strconv.Atoi(d[2])
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rc := NewReader(strings.NewReader(tt.compressed), order, litWidth)
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defer rc.Close()
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b.Reset()
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n, err := io.Copy(&b, rc)
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if err != nil {
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if err != tt.err {
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t.Errorf("%s: io.Copy: %v want %v", tt.desc, err, tt.err)
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}
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continue
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}
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s := b.String()
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if s != tt.raw {
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t.Errorf("%s: got %d-byte %q want %d-byte %q", tt.desc, n, s, len(tt.raw), tt.raw)
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}
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}
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}
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func benchmarkDecoder(b *testing.B, n int) {
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b.StopTimer()
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b.SetBytes(int64(n))
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buf0, _ := ioutil.ReadFile("../testdata/e.txt")
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buf0 = buf0[:10000]
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compressed := new(bytes.Buffer)
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w := NewWriter(compressed, LSB, 8)
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for i := 0; i < n; i += len(buf0) {
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io.Copy(w, bytes.NewBuffer(buf0))
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}
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w.Close()
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buf1 := compressed.Bytes()
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buf0, compressed, w = nil, nil, nil
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runtime.GC()
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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io.Copy(ioutil.Discard, NewReader(bytes.NewBuffer(buf1), LSB, 8))
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}
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}
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func BenchmarkDecoder1e4(b *testing.B) {
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benchmarkDecoder(b, 1e4)
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}
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func BenchmarkDecoder1e5(b *testing.B) {
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benchmarkDecoder(b, 1e5)
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}
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func BenchmarkDecoder1e6(b *testing.B) {
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benchmarkDecoder(b, 1e6)
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}
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