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// Copyright (c) 2017 Christophe-Marie Duquesne <chmd@chmd.fr>
package rabinkarp64_test
import (
"bufio"
"hash"
"log"
"os"
"strings"
"testing"
"github.com/chmduquesne/rollinghash"
rollsum "github.com/chmduquesne/rollinghash/rabinkarp64"
)
var golden = []struct {
out uint64
in string
}{
//{0x0, ""}, // panics
{0x61, "a"},
{0x6162, "ab"},
{0x616263, "abc"},
{0x61626364, "abcd"},
{0x6162636465, "abcde"},
{0x616263646566, "abcdef"},
{0x132021ba359c68, "abcdefg"},
{0x1fce6358ce1471, "abcdefgh"},
{0x65b425e3c80ca, "abcdefghi"},
{0xe9781880ddab2, "abcdefghij"},
{0x1bcc435d5a6760, "Discard medicine more than two years old."},
{0x1c56084394dbf5, "He who has a shady past knows that nice guys finish last."},
{0x7973e4550080f, "I wouldn't marry him with a ten foot pole."},
{0x1e2a9f14d4a366, "Free! Free!/A trip/to Mars/for 900/empty jars/Burma Shave"},
{0x177a1e4d652838, "The days of the digital watch are numbered. -Tom Stoppard"},
{0x153bb8322d8614, "Nepal premier won't resign."},
{0x12309044aaafcd, "For every action there is an equal and opposite government program."},
{0x59187d7f34b99, "His money is twice tainted: 'taint yours and 'taint mine."},
{0x5e4f5ec20dbb, "There is no reason for any individual to have a computer in their home. -Ken Olsen, 1977"},
{0x5b605dca0167a, "It's a tiny change to the code and not completely disgusting. - Bob Manchek"},
{0x1da35eec936b1c, "size: a.out: bad magic"},
{0x1b4a521659269a, "The major problem is with sendmail. -Mark Horton"},
{0x11b3791cfaf6ef, "Give me a rock, paper and scissors and I will move the world. CCFestoon"},
{0x1ff6dcce41d7d9, "If the enemy is within range, then so are you."},
{0x1820adc68f03ec, "It's well we cannot hear the screams/That we create in others' dreams."},
{0x3f8660475a7fb, "You remind me of a TV show, but that's all right: I watch it anyway."},
{0x149d09de60bc54, "C is as portable as Stonehedge!!"},
{0x11686c8f59d7c7, "Even if I could be Shakespeare, I think I should still choose to be Faraday. - A. Huxley"},
{0xfb8afb28c9bcf, "The fugacity of a constituent in a mixture of gases at a given temperature is proportional to its mole fraction. Lewis-Randall Rule"},
{0x1fa10a2313f3e6, "How can you write a big system without C++? -Paul Glick"},
{0x178cc568c9a3c, "'Invariant assertions' is the most elegant programming technique! -Tom Szymanski"},
{0x65bd2936a4628, strings.Repeat("\xff", 5548) + "8"},
{0xe074cdecbffe1, strings.Repeat("\xff", 5549) + "9"},
{0x1378f99580cada, strings.Repeat("\xff", 5550) + "0"},
{0x1b6a3079f8c522, strings.Repeat("\xff", 5551) + "1"},
{0x143e587f656d19, strings.Repeat("\xff", 5552) + "2"},
{0xbadb5a7005edf, strings.Repeat("\xff", 5553) + "3"},
{0xc040bc67bc471, strings.Repeat("\xff", 5554) + "4"},
{0x1758803a1fc391, strings.Repeat("\xff", 5555) + "5"},
{0x0, strings.Repeat("\x00", 1e5)},
{0x4ded86a56a148, strings.Repeat("a", 1e5)},
{0x2b16296a7e5a6, strings.Repeat("ABCDEFGHIJKLMNOPQRSTUVWXYZ", 1e4)},
}
// Prove that we implement rollinghash.Hash64
var _ = rollinghash.Hash64(rollsum.New())
// Prove that we implement hash.Hash64
var _ = hash.Hash64(rollsum.New())
// Sum64ByWriteAndRoll computes the sum by prepending the input slice with
// a '\0', writing the first bytes of this slice into the sum, then
// sliding on the last byte and returning the result of Sum32
func Sum64ByWriteAndRoll(b []byte) uint64 {
q := []byte("\x00")
q = append(q, b...)
roll := rollsum.New()
roll.Write(q[:len(q)-1])
roll.Roll(q[len(q)-1])
return roll.Sum64()
}
func TestGolden(t *testing.T) {
for _, g := range golden {
in := g.in
// We test the classic implementation
p := []byte(g.in)
classic := hash.Hash64(rollsum.New())
classic.Write(p)
if got := classic.Sum64(); got != g.out {
t.Errorf("classic implentation: for %q, expected 0x%x, got 0x%x", in, g.out, got)
continue
}
if got := Sum64ByWriteAndRoll(p); got != g.out {
t.Errorf("rolling implentation: for %q, expected 0x%x, got 0x%x", in, g.out, got)
continue
}
}
}
func BenchmarkRolling64B(b *testing.B) {
b.SetBytes(1024)
b.ReportAllocs()
window := make([]byte, 64)
for i := range window {
window[i] = byte(i)
}
h := rollsum.New()
in := make([]byte, 0, h.Size())
h.Write(window)
b.ResetTimer()
for i := 0; i < b.N; i++ {
h.Roll(byte(i))
h.Sum(in)
}
}
func BenchmarkReadUrandom(b *testing.B) {
b.SetBytes(1024)
b.ReportAllocs()
f, err := os.Open("/dev/urandom")
if err != nil {
b.Errorf("Could not open /dev/urandom")
}
defer func() {
if err := f.Close(); err != nil {
log.Fatal(err)
}
}()
r := bufio.NewReader(f)
ws := 64
window := make([]byte, ws)
n, err := r.Read(window)
if n != ws || err != nil {
b.Errorf("Could not read %d bytes", ws)
}
h := rollsum.New()
in := make([]byte, 0, h.Size())
h.Write(window)
b.ResetTimer()
for i := 0; i < b.N; i++ {
c, err := r.ReadByte()
if err != nil {
b.Errorf("%s", err)
}
h.Roll(c)
h.Sum(in)
}
}
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