github.com/miolini/go@v0.0.0-20160405192216-fca68c8cb408/src/hash/crc32/crc32_test.go (about)

     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 crc32
     6  
     7  import (
     8  	"hash"
     9  	"io"
    10  	"testing"
    11  )
    12  
    13  type test struct {
    14  	ieee, castagnoli uint32
    15  	in               string
    16  }
    17  
    18  var golden = []test{
    19  	{0x0, 0x0, ""},
    20  	{0xe8b7be43, 0xc1d04330, "a"},
    21  	{0x9e83486d, 0xe2a22936, "ab"},
    22  	{0x352441c2, 0x364b3fb7, "abc"},
    23  	{0xed82cd11, 0x92c80a31, "abcd"},
    24  	{0x8587d865, 0xc450d697, "abcde"},
    25  	{0x4b8e39ef, 0x53bceff1, "abcdef"},
    26  	{0x312a6aa6, 0xe627f441, "abcdefg"},
    27  	{0xaeef2a50, 0xa9421b7, "abcdefgh"},
    28  	{0x8da988af, 0x2ddc99fc, "abcdefghi"},
    29  	{0x3981703a, 0xe6599437, "abcdefghij"},
    30  	{0x6b9cdfe7, 0xb2cc01fe, "Discard medicine more than two years old."},
    31  	{0xc90ef73f, 0xe28207f, "He who has a shady past knows that nice guys finish last."},
    32  	{0xb902341f, 0xbe93f964, "I wouldn't marry him with a ten foot pole."},
    33  	{0x42080e8, 0x9e3be0c3, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"},
    34  	{0x154c6d11, 0xf505ef04, "The days of the digital watch are numbered.  -Tom Stoppard"},
    35  	{0x4c418325, 0x85d3dc82, "Nepal premier won't resign."},
    36  	{0x33955150, 0xc5142380, "For every action there is an equal and opposite government program."},
    37  	{0x26216a4b, 0x75eb77dd, "His money is twice tainted: 'taint yours and 'taint mine."},
    38  	{0x1abbe45e, 0x91ebe9f7, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"},
    39  	{0xc89a94f7, 0xf0b1168e, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"},
    40  	{0xab3abe14, 0x572b74e2, "size:  a.out:  bad magic"},
    41  	{0xbab102b6, 0x8a58a6d5, "The major problem is with sendmail.  -Mark Horton"},
    42  	{0x999149d7, 0x9c426c50, "Give me a rock, paper and scissors and I will move the world.  CCFestoon"},
    43  	{0x6d52a33c, 0x735400a4, "If the enemy is within range, then so are you."},
    44  	{0x90631e8d, 0xbec49c95, "It's well we cannot hear the screams/That we create in others' dreams."},
    45  	{0x78309130, 0xa95a2079, "You remind me of a TV show, but that's all right: I watch it anyway."},
    46  	{0x7d0a377f, 0xde2e65c5, "C is as portable as Stonehedge!!"},
    47  	{0x8c79fd79, 0x297a88ed, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"},
    48  	{0xa20b7167, 0x66ed1d8b, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction.  Lewis-Randall Rule"},
    49  	{0x8e0bb443, 0xdcded527, "How can you write a big system without C++?  -Paul Glick"},
    50  }
    51  
    52  func TestGolden(t *testing.T) {
    53  	castagnoliTab := MakeTable(Castagnoli)
    54  
    55  	for _, g := range golden {
    56  		ieee := NewIEEE()
    57  		io.WriteString(ieee, g.in)
    58  		s := ieee.Sum32()
    59  		if s != g.ieee {
    60  			t.Errorf("IEEE(%s) = 0x%x want 0x%x", g.in, s, g.ieee)
    61  		}
    62  
    63  		castagnoli := New(castagnoliTab)
    64  		io.WriteString(castagnoli, g.in)
    65  		s = castagnoli.Sum32()
    66  		if s != g.castagnoli {
    67  			t.Errorf("Castagnoli(%s) = 0x%x want 0x%x", g.in, s, g.castagnoli)
    68  		}
    69  
    70  		if len(g.in) > 0 {
    71  			// The SSE4.2 implementation of this has code to deal
    72  			// with misaligned data so we ensure that we test that
    73  			// too.
    74  			castagnoli = New(castagnoliTab)
    75  			io.WriteString(castagnoli, g.in[:1])
    76  			io.WriteString(castagnoli, g.in[1:])
    77  			s = castagnoli.Sum32()
    78  			if s != g.castagnoli {
    79  				t.Errorf("Castagnoli[misaligned](%s) = 0x%x want 0x%x", g.in, s, g.castagnoli)
    80  			}
    81  		}
    82  	}
    83  }
    84  
    85  func BenchmarkIEEECrc40B(b *testing.B) {
    86  	benchmark(b, NewIEEE(), 40)
    87  }
    88  
    89  func BenchmarkIEEECrc1KB(b *testing.B) {
    90  	benchmark(b, NewIEEE(), 1<<10)
    91  }
    92  
    93  func BenchmarkIEEECrc4KB(b *testing.B) {
    94  	benchmark(b, NewIEEE(), 4<<10)
    95  }
    96  
    97  func BenchmarkIEEECrc32KB(b *testing.B) {
    98  	benchmark(b, NewIEEE(), 32<<10)
    99  }
   100  
   101  func BenchmarkCastagnoliCrc40B(b *testing.B) {
   102  	benchmark(b, New(MakeTable(Castagnoli)), 40)
   103  }
   104  
   105  func BenchmarkCastagnoliCrc1KB(b *testing.B) {
   106  	benchmark(b, New(MakeTable(Castagnoli)), 1<<10)
   107  }
   108  
   109  func BenchmarkCastagnoliCrc4KB(b *testing.B) {
   110  	benchmark(b, New(MakeTable(Castagnoli)), 4<<10)
   111  }
   112  
   113  func BenchmarkCastagnoliCrc32KB(b *testing.B) {
   114  	benchmark(b, New(MakeTable(Castagnoli)), 32<<10)
   115  }
   116  
   117  func benchmark(b *testing.B, h hash.Hash32, n int64) {
   118  	b.SetBytes(n)
   119  	data := make([]byte, n)
   120  	for i := range data {
   121  		data[i] = byte(i)
   122  	}
   123  	in := make([]byte, 0, h.Size())
   124  
   125  	// Warm up
   126  	h.Reset()
   127  	h.Write(data)
   128  	h.Sum(in)
   129  
   130  	b.ResetTimer()
   131  	for i := 0; i < b.N; i++ {
   132  		h.Reset()
   133  		h.Write(data)
   134  		h.Sum(in)
   135  	}
   136  }