mirror of
https://github.com/octoleo/syncthing.git
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285 lines
8.4 KiB
Go
285 lines
8.4 KiB
Go
// Copyright 2009 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 crc32
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import (
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crand "crypto/rand"
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"hash"
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mrand "math/rand"
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"testing"
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)
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type test struct {
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ieee, castagnoli uint32
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in string
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}
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var golden = []test{
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{0x0, 0x0, ""},
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{0xe8b7be43, 0xc1d04330, "a"},
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{0x9e83486d, 0xe2a22936, "ab"},
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{0x352441c2, 0x364b3fb7, "abc"},
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{0xed82cd11, 0x92c80a31, "abcd"},
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{0x8587d865, 0xc450d697, "abcde"},
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{0x4b8e39ef, 0x53bceff1, "abcdef"},
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{0x312a6aa6, 0xe627f441, "abcdefg"},
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{0xaeef2a50, 0xa9421b7, "abcdefgh"},
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{0x8da988af, 0x2ddc99fc, "abcdefghi"},
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{0x3981703a, 0xe6599437, "abcdefghij"},
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{0x6b9cdfe7, 0xb2cc01fe, "Discard medicine more than two years old."},
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{0xc90ef73f, 0xe28207f, "He who has a shady past knows that nice guys finish last."},
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{0xb902341f, 0xbe93f964, "I wouldn't marry him with a ten foot pole."},
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{0x42080e8, 0x9e3be0c3, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"},
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{0x154c6d11, 0xf505ef04, "The days of the digital watch are numbered. -Tom Stoppard"},
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{0x4c418325, 0x85d3dc82, "Nepal premier won't resign."},
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{0x33955150, 0xc5142380, "For every action there is an equal and opposite government program."},
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{0x26216a4b, 0x75eb77dd, "His money is twice tainted: 'taint yours and 'taint mine."},
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{0x1abbe45e, 0x91ebe9f7, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"},
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{0xc89a94f7, 0xf0b1168e, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"},
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{0xab3abe14, 0x572b74e2, "size: a.out: bad magic"},
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{0xbab102b6, 0x8a58a6d5, "The major problem is with sendmail. -Mark Horton"},
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{0x999149d7, 0x9c426c50, "Give me a rock, paper and scissors and I will move the world. CCFestoon"},
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{0x6d52a33c, 0x735400a4, "If the enemy is within range, then so are you."},
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{0x90631e8d, 0xbec49c95, "It's well we cannot hear the screams/That we create in others' dreams."},
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{0x78309130, 0xa95a2079, "You remind me of a TV show, but that's all right: I watch it anyway."},
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{0x7d0a377f, 0xde2e65c5, "C is as portable as Stonehedge!!"},
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{0x8c79fd79, 0x297a88ed, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"},
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{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"},
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{0x8e0bb443, 0xdcded527, "How can you write a big system without C++? -Paul Glick"},
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}
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// testGoldenIEEE verifies that the given function returns
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// correct IEEE checksums.
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func testGoldenIEEE(t *testing.T, crcFunc func(b []byte) uint32) {
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for _, g := range golden {
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if crc := crcFunc([]byte(g.in)); crc != g.ieee {
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t.Errorf("IEEE(%s) = 0x%x want 0x%x", g.in, crc, g.ieee)
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}
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}
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}
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// testGoldenCastagnoli verifies that the given function returns
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// correct IEEE checksums.
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func testGoldenCastagnoli(t *testing.T, crcFunc func(b []byte) uint32) {
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for _, g := range golden {
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if crc := crcFunc([]byte(g.in)); crc != g.castagnoli {
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t.Errorf("Castagnoli(%s) = 0x%x want 0x%x", g.in, crc, g.castagnoli)
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}
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}
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}
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// testCrossCheck generates random buffers of various lengths and verifies that
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// the two "update" functions return the same result.
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func testCrossCheck(t *testing.T, crcFunc1, crcFunc2 func(crc uint32, b []byte) uint32) {
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// The AMD64 implementation has some cutoffs at lengths 168*3=504 and
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// 1344*3=4032. We should make sure lengths around these values are in the
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// list.
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lengths := []int{0, 1, 2, 3, 4, 5, 10, 16, 50, 100, 128,
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500, 501, 502, 503, 504, 505, 512, 1000, 1024, 2000,
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4030, 4031, 4032, 4033, 4036, 4040, 4048, 4096, 5000, 10000}
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for _, length := range lengths {
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p := make([]byte, length)
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_, _ = crand.Read(p)
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crcInit := uint32(mrand.Int63())
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crc1 := crcFunc1(crcInit, p)
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crc2 := crcFunc2(crcInit, p)
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if crc1 != crc2 {
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t.Errorf("mismatch: 0x%x vs 0x%x (buffer length %d)", crc1, crc2, length)
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}
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}
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}
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// TestSimple tests the simple generic algorithm.
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func TestSimple(t *testing.T) {
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tab := simpleMakeTable(IEEE)
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testGoldenIEEE(t, func(b []byte) uint32 {
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return simpleUpdate(0, tab, b)
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})
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tab = simpleMakeTable(Castagnoli)
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testGoldenCastagnoli(t, func(b []byte) uint32 {
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return simpleUpdate(0, tab, b)
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})
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}
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// TestSimple tests the slicing-by-8 algorithm.
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func TestSlicing(t *testing.T) {
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tab := slicingMakeTable(IEEE)
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testGoldenIEEE(t, func(b []byte) uint32 {
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return slicingUpdate(0, tab, b)
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})
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tab = slicingMakeTable(Castagnoli)
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testGoldenCastagnoli(t, func(b []byte) uint32 {
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return slicingUpdate(0, tab, b)
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})
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// Cross-check various polys against the simple algorithm.
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for _, poly := range []uint32{IEEE, Castagnoli, Koopman, 0xD5828281} {
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t1 := simpleMakeTable(poly)
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f1 := func(crc uint32, b []byte) uint32 {
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return simpleUpdate(crc, t1, b)
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}
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t2 := slicingMakeTable(poly)
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f2 := func(crc uint32, b []byte) uint32 {
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return slicingUpdate(crc, t2, b)
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}
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testCrossCheck(t, f1, f2)
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}
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}
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func TestArchIEEE(t *testing.T) {
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if !archAvailableIEEE() {
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t.Skip("Arch-specific IEEE not available.")
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}
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archInitIEEE()
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slicingTable := slicingMakeTable(IEEE)
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testCrossCheck(t, archUpdateIEEE, func(crc uint32, b []byte) uint32 {
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return slicingUpdate(crc, slicingTable, b)
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})
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}
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func TestArchCastagnoli(t *testing.T) {
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if !archAvailableCastagnoli() {
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t.Skip("Arch-specific Castagnoli not available.")
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}
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archInitCastagnoli()
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slicingTable := slicingMakeTable(Castagnoli)
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testCrossCheck(t, archUpdateCastagnoli, func(crc uint32, b []byte) uint32 {
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return slicingUpdate(crc, slicingTable, b)
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})
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}
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func TestGolden(t *testing.T) {
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testGoldenIEEE(t, ChecksumIEEE)
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// Some implementations have special code to deal with misaligned
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// data; test that as well.
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for delta := 1; delta <= 7; delta++ {
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testGoldenIEEE(t, func(b []byte) uint32 {
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ieee := NewIEEE()
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d := delta
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if d >= len(b) {
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d = len(b)
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}
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ieee.Write(b[:d])
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ieee.Write(b[d:])
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return ieee.Sum32()
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})
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}
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castagnoliTab := MakeTable(Castagnoli)
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if castagnoliTab == nil {
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t.Errorf("nil Castagnoli Table")
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}
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testGoldenCastagnoli(t, func(b []byte) uint32 {
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castagnoli := New(castagnoliTab)
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castagnoli.Write(b)
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return castagnoli.Sum32()
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})
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// Some implementations have special code to deal with misaligned
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// data; test that as well.
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for delta := 1; delta <= 7; delta++ {
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testGoldenCastagnoli(t, func(b []byte) uint32 {
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castagnoli := New(castagnoliTab)
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d := delta
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if d >= len(b) {
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d = len(b)
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}
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castagnoli.Write(b[:d])
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castagnoli.Write(b[d:])
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return castagnoli.Sum32()
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})
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}
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}
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func BenchmarkIEEECrc40B(b *testing.B) {
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benchmark(b, NewIEEE(), 40, 0)
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}
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func BenchmarkIEEECrc1KB(b *testing.B) {
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benchmark(b, NewIEEE(), 1<<10, 0)
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}
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func BenchmarkIEEECrc4KB(b *testing.B) {
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benchmark(b, NewIEEE(), 4<<10, 0)
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}
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func BenchmarkIEEECrc32KB(b *testing.B) {
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benchmark(b, NewIEEE(), 32<<10, 0)
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}
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func BenchmarkCastagnoliCrc15B(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 15, 0)
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}
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func BenchmarkCastagnoliCrc15BMisaligned(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 15, 1)
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}
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func BenchmarkCastagnoliCrc40B(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 40, 0)
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}
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func BenchmarkCastagnoliCrc40BMisaligned(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 40, 1)
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}
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func BenchmarkCastagnoliCrc512(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 512, 0)
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}
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func BenchmarkCastagnoliCrc512Misaligned(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 512, 1)
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}
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func BenchmarkCastagnoliCrc1KB(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 1<<10, 0)
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}
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func BenchmarkCastagnoliCrc1KBMisaligned(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 1<<10, 1)
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}
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func BenchmarkCastagnoliCrc4KB(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 4<<10, 0)
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}
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func BenchmarkCastagnoliCrc4KBMisaligned(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 4<<10, 1)
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}
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func BenchmarkCastagnoliCrc32KB(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 32<<10, 0)
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}
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func BenchmarkCastagnoliCrc32KBMisaligned(b *testing.B) {
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benchmark(b, New(MakeTable(Castagnoli)), 32<<10, 1)
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}
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func benchmark(b *testing.B, h hash.Hash32, n, alignment int64) {
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b.SetBytes(n)
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data := make([]byte, n+alignment)
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data = data[alignment:]
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for i := range data {
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data[i] = byte(i)
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}
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in := make([]byte, 0, h.Size())
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// Warm up
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h.Reset()
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h.Write(data)
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h.Sum(in)
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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h.Reset()
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h.Write(data)
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h.Sum(in)
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}
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}
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