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Source file src/compress/bzip2/bzip2_test.go

Documentation: compress/bzip2

  // 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 bzip2
  
  import (
  	"bytes"
  	"encoding/hex"
  	"fmt"
  	"io"
  	"io/ioutil"
  	"testing"
  )
  
  func mustDecodeHex(s string) []byte {
  	b, err := hex.DecodeString(s)
  	if err != nil {
  		panic(err)
  	}
  	return b
  }
  
  func mustLoadFile(f string) []byte {
  	b, err := ioutil.ReadFile(f)
  	if err != nil {
  		panic(err)
  	}
  	return b
  }
  
  func trim(b []byte) string {
  	const limit = 1024
  	if len(b) < limit {
  		return fmt.Sprintf("%q", b)
  	}
  	return fmt.Sprintf("%q...", b[:limit])
  }
  
  func TestReader(t *testing.T) {
  	var vectors = []struct {
  		desc   string
  		input  []byte
  		output []byte
  		fail   bool
  	}{{
  		desc: "hello world",
  		input: mustDecodeHex("" +
  			"425a68393141592653594eece83600000251800010400006449080200031064c" +
  			"4101a7a9a580bb9431f8bb9229c28482776741b0",
  		),
  		output: []byte("hello world\n"),
  	}, {
  		desc: "concatenated files",
  		input: mustDecodeHex("" +
  			"425a68393141592653594eece83600000251800010400006449080200031064c" +
  			"4101a7a9a580bb9431f8bb9229c28482776741b0425a68393141592653594eec" +
  			"e83600000251800010400006449080200031064c4101a7a9a580bb9431f8bb92" +
  			"29c28482776741b0",
  		),
  		output: []byte("hello world\nhello world\n"),
  	}, {
  		desc: "32B zeros",
  		input: mustDecodeHex("" +
  			"425a6839314159265359b5aa5098000000600040000004200021008283177245" +
  			"385090b5aa5098",
  		),
  		output: make([]byte, 32),
  	}, {
  		desc: "1MiB zeros",
  		input: mustDecodeHex("" +
  			"425a683931415926535938571ce50008084000c0040008200030cc0529a60806" +
  			"c4201e2ee48a70a12070ae39ca",
  		),
  		output: make([]byte, 1<<20),
  	}, {
  		desc:   "random data",
  		input:  mustLoadFile("testdata/pass-random1.bz2"),
  		output: mustLoadFile("testdata/pass-random1.bin"),
  	}, {
  		desc:   "random data - full symbol range",
  		input:  mustLoadFile("testdata/pass-random2.bz2"),
  		output: mustLoadFile("testdata/pass-random2.bin"),
  	}, {
  		desc: "random data - uses RLE1 stage",
  		input: mustDecodeHex("" +
  			"425a6839314159265359d992d0f60000137dfe84020310091c1e280e100e0428" +
  			"01099210094806c0110002e70806402000546034000034000000f28300000320" +
  			"00d3403264049270eb7a9280d308ca06ad28f6981bee1bf8160727c7364510d7" +
  			"3a1e123083421b63f031f63993a0f40051fbf177245385090d992d0f60",
  		),
  		output: mustDecodeHex("" +
  			"92d5652616ac444a4a04af1a8a3964aca0450d43d6cf233bd03233f4ba92f871" +
  			"9e6c2a2bd4f5f88db07ecd0da3a33b263483db9b2c158786ad6363be35d17335" +
  			"ba",
  		),
  	}, {
  		desc:  "1MiB sawtooth",
  		input: mustLoadFile("testdata/pass-sawtooth.bz2"),
  		output: func() []byte {
  			b := make([]byte, 1<<20)
  			for i := range b {
  				b[i] = byte(i)
  			}
  			return b
  		}(),
  	}, {
  		desc:  "RLE2 buffer overrun - issue 5747",
  		input: mustLoadFile("testdata/fail-issue5747.bz2"),
  		fail:  true,
  	}, {
  		desc: "out-of-range selector - issue 8363",
  		input: mustDecodeHex("" +
  			"425a68393141592653594eece83600000251800010400006449080200031064c" +
  			"4101a7a9a580bb943117724538509000000000",
  		),
  		fail: true,
  	}, {
  		desc: "bad block size - issue 13941",
  		input: mustDecodeHex("" +
  			"425a683131415926535936dc55330063ffc0006000200020a40830008b0008b8" +
  			"bb9229c28481b6e2a998",
  		),
  		fail: true,
  	}, {
  		desc: "bad huffman delta",
  		input: mustDecodeHex("" +
  			"425a6836314159265359b1f7404b000000400040002000217d184682ee48a70a" +
  			"12163ee80960",
  		),
  		fail: true,
  	}}
  
  	for i, v := range vectors {
  		rd := NewReader(bytes.NewReader(v.input))
  		buf, err := ioutil.ReadAll(rd)
  
  		if fail := bool(err != nil); fail != v.fail {
  			if fail {
  				t.Errorf("test %d (%s), unexpected failure: %v", i, v.desc, err)
  			} else {
  				t.Errorf("test %d (%s), unexpected success", i, v.desc)
  			}
  		}
  		if !v.fail && !bytes.Equal(buf, v.output) {
  			t.Errorf("test %d (%s), output mismatch:\ngot  %s\nwant %s", i, v.desc, trim(buf), trim(v.output))
  		}
  	}
  }
  
  func TestBitReader(t *testing.T) {
  	var vectors = []struct {
  		nbits uint // Number of bits to read
  		value int  // Expected output value (0 for error)
  		fail  bool // Expected operation failure?
  	}{
  		{nbits: 1, value: 1},
  		{nbits: 1, value: 0},
  		{nbits: 1, value: 1},
  		{nbits: 5, value: 11},
  		{nbits: 32, value: 0x12345678},
  		{nbits: 15, value: 14495},
  		{nbits: 3, value: 6},
  		{nbits: 6, value: 13},
  		{nbits: 1, fail: true},
  	}
  
  	rd := bytes.NewReader([]byte{0xab, 0x12, 0x34, 0x56, 0x78, 0x71, 0x3f, 0x8d})
  	br := newBitReader(rd)
  	for i, v := range vectors {
  		val := br.ReadBits(v.nbits)
  		if fail := bool(br.err != nil); fail != v.fail {
  			if fail {
  				t.Errorf("test %d, unexpected failure: ReadBits(%d) = %v", i, v.nbits, br.err)
  			} else {
  				t.Errorf("test %d, unexpected success: ReadBits(%d) = nil", i, v.nbits)
  			}
  		}
  		if !v.fail && val != v.value {
  			t.Errorf("test %d, mismatching value: ReadBits(%d) = %d, want %d", i, v.nbits, val, v.value)
  		}
  	}
  }
  
  func TestMTF(t *testing.T) {
  	var vectors = []struct {
  		idx int   // Input index
  		sym uint8 // Expected output symbol
  	}{
  		{idx: 1, sym: 1}, // [1 0 2 3 4]
  		{idx: 0, sym: 1}, // [1 0 2 3 4]
  		{idx: 1, sym: 0}, // [0 1 2 3 4]
  		{idx: 4, sym: 4}, // [4 0 1 2 3]
  		{idx: 1, sym: 0}, // [0 4 1 2 3]
  	}
  
  	mtf := newMTFDecoderWithRange(5)
  	for i, v := range vectors {
  		sym := mtf.Decode(v.idx)
  		t.Log(mtf)
  		if sym != v.sym {
  			t.Errorf("test %d, symbol mismatch: Decode(%d) = %d, want %d", i, v.idx, sym, v.sym)
  		}
  	}
  }
  
  var (
  	digits = mustLoadFile("testdata/e.txt.bz2")
  	twain  = mustLoadFile("testdata/Mark.Twain-Tom.Sawyer.txt.bz2")
  	random = mustLoadFile("testdata/random.data.bz2")
  )
  
  func benchmarkDecode(b *testing.B, compressed []byte) {
  	// Determine the uncompressed size of testfile.
  	uncompressedSize, err := io.Copy(ioutil.Discard, NewReader(bytes.NewReader(compressed)))
  	if err != nil {
  		b.Fatal(err)
  	}
  
  	b.SetBytes(uncompressedSize)
  	b.ReportAllocs()
  	b.ResetTimer()
  
  	for i := 0; i < b.N; i++ {
  		r := bytes.NewReader(compressed)
  		io.Copy(ioutil.Discard, NewReader(r))
  	}
  }
  
  func BenchmarkDecodeDigits(b *testing.B) { benchmarkDecode(b, digits) }
  func BenchmarkDecodeTwain(b *testing.B)  { benchmarkDecode(b, twain) }
  func BenchmarkDecodeRand(b *testing.B)   { benchmarkDecode(b, random) }
  

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