// Copyright 2009 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 crc32 import ( "encoding" "fmt" "hash" "io" "math/rand" "testing" ) type test struct { ieee, castagnoli uint32 in string halfStateIEEE string // IEEE marshaled hash state after first half of in written, used by TestGoldenMarshal halfStateCastagnoli string // Castagnoli marshaled hash state after first half of in written, used by TestGoldenMarshal } var golden = []test{ {0x0, 0x0, "", "crc\x01ʇ\x91M\x00\x00\x00\x00", "crc\x01wB\x84\x81\x00\x00\x00\x00"}, {0xe8b7be43, 0xc1d04330, "a", "crc\x01ʇ\x91M\x00\x00\x00\x00", "crc\x01wB\x84\x81\x00\x00\x00\x00"}, {0x9e83486d, 0xe2a22936, "ab", "crc\x01ʇ\x91M跾C", "crc\x01wB\x84\x81\xc1\xd0C0"}, {0x352441c2, 0x364b3fb7, "abc", "crc\x01ʇ\x91M跾C", "crc\x01wB\x84\x81\xc1\xd0C0"}, {0xed82cd11, 0x92c80a31, "abcd", "crc\x01ʇ\x91M\x9e\x83Hm", "crc\x01wB\x84\x81\xe2\xa2)6"}, {0x8587d865, 0xc450d697, "abcde", "crc\x01ʇ\x91M\x9e\x83Hm", "crc\x01wB\x84\x81\xe2\xa2)6"}, {0x4b8e39ef, 0x53bceff1, "abcdef", "crc\x01ʇ\x91M5$A\xc2", "crc\x01wB\x84\x816K?\xb7"}, {0x312a6aa6, 0xe627f441, "abcdefg", "crc\x01ʇ\x91M5$A\xc2", "crc\x01wB\x84\x816K?\xb7"}, {0xaeef2a50, 0xa9421b7, "abcdefgh", "crc\x01ʇ\x91M\xed\x82\xcd\x11", "crc\x01wB\x84\x81\x92\xc8\n1"}, {0x8da988af, 0x2ddc99fc, "abcdefghi", "crc\x01ʇ\x91M\xed\x82\xcd\x11", "crc\x01wB\x84\x81\x92\xc8\n1"}, {0x3981703a, 0xe6599437, "abcdefghij", "crc\x01ʇ\x91M\x85\x87\xd8e", "crc\x01wB\x84\x81\xc4P֗"}, {0x6b9cdfe7, 0xb2cc01fe, "Discard medicine more than two years old.", "crc\x01ʇ\x91M\xfd\xe5\xc2J", "crc\x01wB\x84\x81S\"(\xe0"}, {0xc90ef73f, 0xe28207f, "He who has a shady past knows that nice guys finish last.", "crc\x01ʇ\x91M\x01Nj+", "crc\x01wB\x84\x81'\xdaR\x15"}, {0xb902341f, 0xbe93f964, "I wouldn't marry him with a ten foot pole.", "crc\x01ʇ\x91M\x9d\x13\xce\x10", "crc\x01wB\x84\x81\xc3\xed\xabG"}, {0x42080e8, 0x9e3be0c3, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave", "crc\x01ʇ\x91M-\xed\xf7\x94", "crc\x01wB\x84\x81\xce\xceb\x81"}, {0x154c6d11, 0xf505ef04, "The days of the digital watch are numbered. -Tom Stoppard", "crc\x01ʇ\x91MOa\xa5\r", "crc\x01wB\x84\x81\xd3s\x9dP"}, {0x4c418325, 0x85d3dc82, "Nepal premier won't resign.", "crc\x01ʇ\x91M\xa8S9\x85", "crc\x01wB\x84\x81{\x90\x8a\x14"}, {0x33955150, 0xc5142380, "For every action there is an equal and opposite government program.", "crc\x01ʇ\x91Ma\xe9>\x86", "crc\x01wB\x84\x81\xaa@\xc4\x1c"}, {0x26216a4b, 0x75eb77dd, "His money is twice tainted: 'taint yours and 'taint mine.", "crc\x01ʇ\x91M\\\x1an\x88", "crc\x01wB\x84\x81W\a8Z"}, {0x1abbe45e, 0x91ebe9f7, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977", "crc\x01ʇ\x91M\xb7\xf5\xf2\xca", "crc\x01wB\x84\x81\xc4o\x9d\x85"}, {0xc89a94f7, 0xf0b1168e, "It's a tiny change to the code and not completely disgusting. - Bob Manchek", "crc\x01ʇ\x91M\x84g1\xe8", "crc\x01wB\x84\x81#\x98\f\xab"}, {0xab3abe14, 0x572b74e2, "size: a.out: bad magic", "crc\x01ʇ\x91M\x8a\x0f\xad\b", "crc\x01wB\x84\x81\x80\xc9n\xd8"}, {0xbab102b6, 0x8a58a6d5, "The major problem is with sendmail. -Mark Horton", "crc\x01ʇ\x91M\a\xf0\xb3\x15", "crc\x01wB\x84\x81liS\xcc"}, {0x999149d7, 0x9c426c50, "Give me a rock, paper and scissors and I will move the world. CCFestoon", "crc\x01ʇ\x91M\x0fa\xbc.", "crc\x01wB\x84\x81\xdb͏C"}, {0x6d52a33c, 0x735400a4, "If the enemy is within range, then so are you.", "crc\x01ʇ\x91My\x1b\x99\xf8", "crc\x01wB\x84\x81\xaaB\x037"}, {0x90631e8d, 0xbec49c95, "It's well we cannot hear the screams/That we create in others' dreams.", "crc\x01ʇ\x91M\bqfY", "crc\x01wB\x84\x81\x16y\xa1\xd2"}, {0x78309130, 0xa95a2079, "You remind me of a TV show, but that's all right: I watch it anyway.", "crc\x01ʇ\x91M\xbdO,\xc2", "crc\x01wB\x84\x81f&\xc5\xe4"}, {0x7d0a377f, 0xde2e65c5, "C is as portable as Stonehedge!!", "crc\x01ʇ\x91M\xf7\xd6\x00\xd5", "crc\x01wB\x84\x81de\\\xf8"}, {0x8c79fd79, 0x297a88ed, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley", "crc\x01ʇ\x91Ml+\xb8\xa7", "crc\x01wB\x84\x81\xbf\xd6S\xdd"}, {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", "crc\x01ʇ\x91M<lR[", "crc\x01wB\x84\x81{\xaco\xb1"}, {0x8e0bb443, 0xdcded527, "How can you write a big system without C++? -Paul Glick", "crc\x01ʇ\x91M\x0e\x88\x89\xed", "crc\x01wB\x84\x813\xd7C\u007f"}, } // testGoldenIEEE verifies that the given function returns // correct IEEE checksums. func testGoldenIEEE(t *testing.T, crcFunc func(b []byte) uint32) { for _, g := range golden { if crc := crcFunc([]byte(g.in)); crc != g.ieee { t.Errorf("IEEE(%s) = 0x%x want 0x%x", g.in, crc, g.ieee) } } } // testGoldenCastagnoli verifies that the given function returns // correct IEEE checksums. func testGoldenCastagnoli(t *testing.T, crcFunc func(b []byte) uint32) { for _, g := range golden { if crc := crcFunc([]byte(g.in)); crc != g.castagnoli { t.Errorf("Castagnoli(%s) = 0x%x want 0x%x", g.in, crc, g.castagnoli) } } } // testCrossCheck generates random buffers of various lengths and verifies that // the two "update" functions return the same result. func testCrossCheck(t *testing.T, crcFunc1, crcFunc2 func(crc uint32, b []byte) uint32) { // The AMD64 implementation has some cutoffs at lengths 168*3=504 and // 1344*3=4032. We should make sure lengths around these values are in the // list. lengths := []int{0, 1, 2, 3, 4, 5, 10, 16, 50, 63, 64, 65, 100, 127, 128, 129, 255, 256, 257, 300, 312, 384, 416, 448, 480, 500, 501, 502, 503, 504, 505, 512, 513, 1000, 1024, 2000, 4030, 4031, 4032, 4033, 4036, 4040, 4048, 4096, 5000, 10000} for _, length := range lengths { p := make([]byte, length) _, _ = rand.Read(p) crcInit := uint32(rand.Int63()) crc1 := crcFunc1(crcInit, p) crc2 := crcFunc2(crcInit, p) if crc1 != crc2 { t.Errorf("mismatch: 0x%x vs 0x%x (buffer length %d)", crc1, crc2, length) } } } // TestSimple tests the simple generic algorithm. func TestSimple(t *testing.T) { tab := simpleMakeTable(IEEE) testGoldenIEEE(t, func(b []byte) uint32 { return simpleUpdate(0, tab, b) }) tab = simpleMakeTable(Castagnoli) testGoldenCastagnoli(t, func(b []byte) uint32 { return simpleUpdate(0, tab, b) }) } func TestGoldenMarshal(t *testing.T) { t.Run("IEEE", func(t *testing.T) { for _, g := range golden { h := New(IEEETable) h2 := New(IEEETable) io.WriteString(h, g.in[:len(g.in)/2]) state, err := h.(encoding.BinaryMarshaler).MarshalBinary() if err != nil { t.Errorf("could not marshal: %v", err) continue } if string(state) != g.halfStateIEEE { t.Errorf("IEEE(%q) state = %q, want %q", g.in, state, g.halfStateIEEE) continue } if err := h2.(encoding.BinaryUnmarshaler).UnmarshalBinary(state); err != nil { t.Errorf("could not unmarshal: %v", err) continue } io.WriteString(h, g.in[len(g.in)/2:]) io.WriteString(h2, g.in[len(g.in)/2:]) if h.Sum32() != h2.Sum32() { t.Errorf("IEEE(%s) = 0x%x != marshaled 0x%x", g.in, h.Sum32(), h2.Sum32()) } } }) t.Run("Castagnoli", func(t *testing.T) { table := MakeTable(Castagnoli) for _, g := range golden { h := New(table) h2 := New(table) io.WriteString(h, g.in[:len(g.in)/2]) state, err := h.(encoding.BinaryMarshaler).MarshalBinary() if err != nil { t.Errorf("could not marshal: %v", err) continue } if string(state) != g.halfStateCastagnoli { t.Errorf("Castagnoli(%q) state = %q, want %q", g.in, state, g.halfStateCastagnoli) continue } if err := h2.(encoding.BinaryUnmarshaler).UnmarshalBinary(state); err != nil { t.Errorf("could not unmarshal: %v", err) continue } io.WriteString(h, g.in[len(g.in)/2:]) io.WriteString(h2, g.in[len(g.in)/2:]) if h.Sum32() != h2.Sum32() { t.Errorf("Castagnoli(%s) = 0x%x != marshaled 0x%x", g.in, h.Sum32(), h2.Sum32()) } } }) } func TestMarshalTableMismatch(t *testing.T) { h1 := New(IEEETable) h2 := New(MakeTable(Castagnoli)) state1, err := h1.(encoding.BinaryMarshaler).MarshalBinary() if err != nil { t.Errorf("could not marshal: %v", err) } if err := h2.(encoding.BinaryUnmarshaler).UnmarshalBinary(state1); err == nil { t.Errorf("no error when one was expected") } } // TestSimple tests the slicing-by-8 algorithm. func TestSlicing(t *testing.T) { tab := slicingMakeTable(IEEE) testGoldenIEEE(t, func(b []byte) uint32 { return slicingUpdate(0, tab, b) }) tab = slicingMakeTable(Castagnoli) testGoldenCastagnoli(t, func(b []byte) uint32 { return slicingUpdate(0, tab, b) }) // Cross-check various polys against the simple algorithm. for _, poly := range []uint32{IEEE, Castagnoli, Koopman, 0xD5828281} { t1 := simpleMakeTable(poly) f1 := func(crc uint32, b []byte) uint32 { return simpleUpdate(crc, t1, b) } t2 := slicingMakeTable(poly) f2 := func(crc uint32, b []byte) uint32 { return slicingUpdate(crc, t2, b) } testCrossCheck(t, f1, f2) } } func TestArchIEEE(t *testing.T) { if !archAvailableIEEE() { t.Skip("Arch-specific IEEE not available.") } archInitIEEE() slicingTable := slicingMakeTable(IEEE) testCrossCheck(t, archUpdateIEEE, func(crc uint32, b []byte) uint32 { return slicingUpdate(crc, slicingTable, b) }) } func TestArchCastagnoli(t *testing.T) { if !archAvailableCastagnoli() { t.Skip("Arch-specific Castagnoli not available.") } archInitCastagnoli() slicingTable := slicingMakeTable(Castagnoli) testCrossCheck(t, archUpdateCastagnoli, func(crc uint32, b []byte) uint32 { return slicingUpdate(crc, slicingTable, b) }) } func TestGolden(t *testing.T) { testGoldenIEEE(t, ChecksumIEEE) // Some implementations have special code to deal with misaligned // data; test that as well. for delta := 1; delta <= 7; delta++ { testGoldenIEEE(t, func(b []byte) uint32 { ieee := NewIEEE() d := delta if d >= len(b) { d = len(b) } ieee.Write(b[:d]) ieee.Write(b[d:]) return ieee.Sum32() }) } castagnoliTab := MakeTable(Castagnoli) if castagnoliTab == nil { t.Errorf("nil Castagnoli Table") } testGoldenCastagnoli(t, func(b []byte) uint32 { castagnoli := New(castagnoliTab) castagnoli.Write(b) return castagnoli.Sum32() }) // Some implementations have special code to deal with misaligned // data; test that as well. for delta := 1; delta <= 7; delta++ { testGoldenCastagnoli(t, func(b []byte) uint32 { castagnoli := New(castagnoliTab) d := delta if d >= len(b) { d = len(b) } castagnoli.Write(b[:d]) castagnoli.Write(b[d:]) return castagnoli.Sum32() }) } } func BenchmarkCRC32(b *testing.B) { b.Run("poly=IEEE", benchmarkAll(NewIEEE())) b.Run("poly=Castagnoli", benchmarkAll(New(MakeTable(Castagnoli)))) b.Run("poly=Koopman", benchmarkAll(New(MakeTable(Koopman)))) } func benchmarkAll(h hash.Hash32) func(b *testing.B) { return func(b *testing.B) { for _, size := range []int{15, 40, 512, 1 << 10, 4 << 10, 32 << 10} { name := fmt.Sprint(size) if size >= 1024 { name = fmt.Sprintf("%dkB", size/1024) } b.Run("size="+name, func(b *testing.B) { for align := 0; align <= 1; align++ { b.Run(fmt.Sprintf("align=%d", align), func(b *testing.B) { benchmark(b, h, int64(size), int64(align)) }) } }) } } } func benchmark(b *testing.B, h hash.Hash32, n, alignment int64) { b.SetBytes(n) data := make([]byte, n+alignment) data = data[alignment:] for i := range data { data[i] = byte(i) } in := make([]byte, 0, h.Size()) // Warm up h.Reset() h.Write(data) h.Sum(in) b.ResetTimer() for i := 0; i < b.N; i++ { h.Reset() h.Write(data) h.Sum(in) } }