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 adler32 6 7 import ( 8 "strings" 9 "testing" 10 ) 11 12 var golden = []struct { 13 out uint32 14 in string 15 }{ 16 {0x00000001, ""}, 17 {0x00620062, "a"}, 18 {0x012600c4, "ab"}, 19 {0x024d0127, "abc"}, 20 {0x03d8018b, "abcd"}, 21 {0x05c801f0, "abcde"}, 22 {0x081e0256, "abcdef"}, 23 {0x0adb02bd, "abcdefg"}, 24 {0x0e000325, "abcdefgh"}, 25 {0x118e038e, "abcdefghi"}, 26 {0x158603f8, "abcdefghij"}, 27 {0x3f090f02, "Discard medicine more than two years old."}, 28 {0x46d81477, "He who has a shady past knows that nice guys finish last."}, 29 {0x40ee0ee1, "I wouldn't marry him with a ten foot pole."}, 30 {0x16661315, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"}, 31 {0x5b2e1480, "The days of the digital watch are numbered. -Tom Stoppard"}, 32 {0x8c3c09ea, "Nepal premier won't resign."}, 33 {0x45ac18fd, "For every action there is an equal and opposite government program."}, 34 {0x53c61462, "His money is twice tainted: 'taint yours and 'taint mine."}, 35 {0x7e511e63, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"}, 36 {0xe4801a6a, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"}, 37 {0x61b507df, "size: a.out: bad magic"}, 38 {0xb8631171, "The major problem is with sendmail. -Mark Horton"}, 39 {0x8b5e1904, "Give me a rock, paper and scissors and I will move the world. CCFestoon"}, 40 {0x7cc6102b, "If the enemy is within range, then so are you."}, 41 {0x700318e7, "It's well we cannot hear the screams/That we create in others' dreams."}, 42 {0x1e601747, "You remind me of a TV show, but that's all right: I watch it anyway."}, 43 {0xb55b0b09, "C is as portable as Stonehedge!!"}, 44 {0x39111dd0, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"}, 45 {0x91dd304f, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction. Lewis-Randall Rule"}, 46 {0x2e5d1316, "How can you write a big system without C++? -Paul Glick"}, 47 {0xd0201df6, "'Invariant assertions' is the most elegant programming technique! -Tom Szymanski"}, 48 {0x211297c8, strings.Repeat("\xff", 5548) + "8"}, 49 {0xbaa198c8, strings.Repeat("\xff", 5549) + "9"}, 50 {0x553499be, strings.Repeat("\xff", 5550) + "0"}, 51 {0xf0c19abe, strings.Repeat("\xff", 5551) + "1"}, 52 {0x8d5c9bbe, strings.Repeat("\xff", 5552) + "2"}, 53 {0x2af69cbe, strings.Repeat("\xff", 5553) + "3"}, 54 {0xc9809dbe, strings.Repeat("\xff", 5554) + "4"}, 55 {0x69189ebe, strings.Repeat("\xff", 5555) + "5"}, 56 {0x86af0001, strings.Repeat("\x00", 1e5)}, 57 {0x79660b4d, strings.Repeat("a", 1e5)}, 58 {0x110588ee, strings.Repeat("ABCDEFGHIJKLMNOPQRSTUVWXYZ", 1e4)}, 59 } 60 61 // checksum is a slow but simple implementation of the Adler-32 checksum. 62 // It is a straight port of the sample code in RFC 1950 section 9. 63 func checksum(p []byte) uint32 { 64 s1, s2 := uint32(1), uint32(0) 65 for _, x := range p { 66 s1 = (s1 + uint32(x)) % mod 67 s2 = (s2 + s1) % mod 68 } 69 return s2<<16 | s1 70 } 71 72 func TestGolden(t *testing.T) { 73 for _, g := range golden { 74 in := g.in 75 if len(in) > 220 { 76 in = in[:100] + "..." + in[len(in)-100:] 77 } 78 p := []byte(g.in) 79 if got := checksum(p); got != g.out { 80 t.Errorf("simple implementation: checksum(%q) = 0x%x want 0x%x", in, got, g.out) 81 continue 82 } 83 if got := Checksum(p); got != g.out { 84 t.Errorf("optimized implementation: Checksum(%q) = 0x%x want 0x%x", in, got, g.out) 85 continue 86 } 87 } 88 } 89 90 func BenchmarkAdler32KB(b *testing.B) { 91 b.SetBytes(1024) 92 data := make([]byte, 1024) 93 for i := range data { 94 data[i] = byte(i) 95 } 96 h := New() 97 in := make([]byte, 0, h.Size()) 98 99 b.ResetTimer() 100 for i := 0; i < b.N; i++ { 101 h.Reset() 102 h.Write(data) 103 h.Sum(in) 104 } 105 } 106
