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      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 	"io"
      9 	"testing"
     10 )
     11 
     12 type test struct {
     13 	ieee, castagnoli uint32
     14 	in               string
     15 }
     16 
     17 var golden = []test{
     18 	{0x0, 0x0, ""},
     19 	{0xe8b7be43, 0xc1d04330, "a"},
     20 	{0x9e83486d, 0xe2a22936, "ab"},
     21 	{0x352441c2, 0x364b3fb7, "abc"},
     22 	{0xed82cd11, 0x92c80a31, "abcd"},
     23 	{0x8587d865, 0xc450d697, "abcde"},
     24 	{0x4b8e39ef, 0x53bceff1, "abcdef"},
     25 	{0x312a6aa6, 0xe627f441, "abcdefg"},
     26 	{0xaeef2a50, 0xa9421b7, "abcdefgh"},
     27 	{0x8da988af, 0x2ddc99fc, "abcdefghi"},
     28 	{0x3981703a, 0xe6599437, "abcdefghij"},
     29 	{0x6b9cdfe7, 0xb2cc01fe, "Discard medicine more than two years old."},
     30 	{0xc90ef73f, 0xe28207f, "He who has a shady past knows that nice guys finish last."},
     31 	{0xb902341f, 0xbe93f964, "I wouldn't marry him with a ten foot pole."},
     32 	{0x42080e8, 0x9e3be0c3, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"},
     33 	{0x154c6d11, 0xf505ef04, "The days of the digital watch are numbered.  -Tom Stoppard"},
     34 	{0x4c418325, 0x85d3dc82, "Nepal premier won't resign."},
     35 	{0x33955150, 0xc5142380, "For every action there is an equal and opposite government program."},
     36 	{0x26216a4b, 0x75eb77dd, "His money is twice tainted: 'taint yours and 'taint mine."},
     37 	{0x1abbe45e, 0x91ebe9f7, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"},
     38 	{0xc89a94f7, 0xf0b1168e, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"},
     39 	{0xab3abe14, 0x572b74e2, "size:  a.out:  bad magic"},
     40 	{0xbab102b6, 0x8a58a6d5, "The major problem is with sendmail.  -Mark Horton"},
     41 	{0x999149d7, 0x9c426c50, "Give me a rock, paper and scissors and I will move the world.  CCFestoon"},
     42 	{0x6d52a33c, 0x735400a4, "If the enemy is within range, then so are you."},
     43 	{0x90631e8d, 0xbec49c95, "It's well we cannot hear the screams/That we create in others' dreams."},
     44 	{0x78309130, 0xa95a2079, "You remind me of a TV show, but that's all right: I watch it anyway."},
     45 	{0x7d0a377f, 0xde2e65c5, "C is as portable as Stonehedge!!"},
     46 	{0x8c79fd79, 0x297a88ed, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"},
     47 	{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"},
     48 	{0x8e0bb443, 0xdcded527, "How can you write a big system without C++?  -Paul Glick"},
     49 }
     50 
     51 func TestGolden(t *testing.T) {
     52 	castagnoliTab := MakeTable(Castagnoli)
     53 
     54 	for _, g := range golden {
     55 		ieee := NewIEEE()
     56 		io.WriteString(ieee, g.in)
     57 		s := ieee.Sum32()
     58 		if s != g.ieee {
     59 			t.Errorf("IEEE(%s) = 0x%x want 0x%x", g.in, s, g.ieee)
     60 		}
     61 
     62 		castagnoli := New(castagnoliTab)
     63 		io.WriteString(castagnoli, g.in)
     64 		s = castagnoli.Sum32()
     65 		if s != g.castagnoli {
     66 			t.Errorf("Castagnoli(%s) = 0x%x want 0x%x", g.in, s, g.castagnoli)
     67 		}
     68 
     69 		if len(g.in) > 0 {
     70 			// The SSE4.2 implementation of this has code to deal
     71 			// with misaligned data so we ensure that we test that
     72 			// too.
     73 			castagnoli = New(castagnoliTab)
     74 			io.WriteString(castagnoli, g.in[:1])
     75 			io.WriteString(castagnoli, g.in[1:])
     76 			s = castagnoli.Sum32()
     77 			if s != g.castagnoli {
     78 				t.Errorf("Castagnoli[misaligned](%s) = 0x%x want 0x%x", g.in, s, g.castagnoli)
     79 			}
     80 		}
     81 	}
     82 }
     83 
     84 func BenchmarkIEEECrc1KB(b *testing.B) {
     85 	b.SetBytes(1024)
     86 	data := make([]byte, 1024)
     87 	for i := range data {
     88 		data[i] = byte(i)
     89 	}
     90 	h := NewIEEE()
     91 	in := make([]byte, 0, h.Size())
     92 
     93 	b.ResetTimer()
     94 	for i := 0; i < b.N; i++ {
     95 		h.Reset()
     96 		h.Write(data)
     97 		h.Sum(in)
     98 	}
     99 }
    100 
    101 func BenchmarkIEEECrc4KB(b *testing.B) {
    102 	b.SetBytes(4096)
    103 	data := make([]byte, 4096)
    104 	for i := range data {
    105 		data[i] = byte(i)
    106 	}
    107 	h := NewIEEE()
    108 	in := make([]byte, 0, h.Size())
    109 
    110 	b.ResetTimer()
    111 	for i := 0; i < b.N; i++ {
    112 		h.Reset()
    113 		h.Write(data)
    114 		h.Sum(in)
    115 	}
    116 }
    117 
    118 func BenchmarkCastagnoliCrc1KB(b *testing.B) {
    119 	b.SetBytes(1024)
    120 	data := make([]byte, 1024)
    121 	for i := range data {
    122 		data[i] = byte(i)
    123 	}
    124 	h := New(MakeTable(Castagnoli))
    125 	in := make([]byte, 0, h.Size())
    126 
    127 	b.ResetTimer()
    128 	for i := 0; i < b.N; i++ {
    129 		h.Reset()
    130 		h.Write(data)
    131 		h.Sum(in)
    132 	}
    133 }
    134