// Copyright 2010 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 suffixarray
import (
"bytes"
"fmt"
"io/ioutil"
"math/rand"
"os"
"path/filepath"
"regexp"
"sort"
"strings"
"testing"
)
type testCase struct {
name string // name of test case
source string // source to index
patterns []string // patterns to lookup
}
var testCases = []testCase{
{
"empty string",
"",
[]string{
"",
"foo",
"(foo)",
".*",
"a*",
},
},
{
"all a's",
"aaaaaaaaaa", // 10 a's
[]string{
"",
"a",
"aa",
"aaa",
"aaaa",
"aaaaa",
"aaaaaa",
"aaaaaaa",
"aaaaaaaa",
"aaaaaaaaa",
"aaaaaaaaaa",
"aaaaaaaaaaa", // 11 a's
".",
".*",
"a+",
"aa+",
"aaaa[b]?",
"aaa*",
},
},
{
"abc",
"abc",
[]string{
"a",
"b",
"c",
"ab",
"bc",
"abc",
"a.c",
"a(b|c)",
"abc?",
},
},
{
"barbara*3",
"barbarabarbarabarbara",
[]string{
"a",
"bar",
"rab",
"arab",
"barbar",
"bara?bar",
},
},
{
"typing drill",
"Now is the time for all good men to come to the aid of their country.",
[]string{
"Now",
"the time",
"to come the aid",
"is the time for all good men to come to the aid of their",
"to (come|the)?",
},
},
{
"godoc simulation",
"package main\n\nimport(\n \"rand\"\n ",
[]string{},
},
}
// find all occurrences of s in source; report at most n occurrences
func find(src, s string, n int) []int {
var res []int
if s != "" && n != 0 {
// find at most n occurrences of s in src
for i := -1; n < 0 || len(res) < n; {
j := strings.Index(src[i+1:], s)
if j < 0 {
break
}
i += j + 1
res = append(res, i)
}
}
return res
}
func testLookup(t *testing.T, tc *testCase, x *Index, s string, n int) {
res := x.Lookup([]byte(s), n)
exp := find(tc.source, s, n)
// check that the lengths match
if len(res) != len(exp) {
t.Errorf("test %q, lookup %q (n = %d): expected %d results; got %d", tc.name, s, n, len(exp), len(res))
}
// if n >= 0 the number of results is limited --- unless n >= all results,
// we may obtain different positions from the Index and from find (because
// Index may not find the results in the same order as find) => in general
// we cannot simply check that the res and exp lists are equal
// check that each result is in fact a correct match and there are no duplicates
sort.Ints(res)
for i, r := range res {
if r < 0 || len(tc.source) <= r {
t.Errorf("test %q, lookup %q, result %d (n = %d): index %d out of range [0, %d[", tc.name, s, i, n, r, len(tc.source))
} else if !strings.HasPrefix(tc.source[r:], s) {
t.Errorf("test %q, lookup %q, result %d (n = %d): index %d not a match", tc.name, s, i, n, r)
}
if i > 0 && res[i-1] == r {
t.Errorf("test %q, lookup %q, result %d (n = %d): found duplicate index %d", tc.name, s, i, n, r)
}
}
if n < 0 {
// all results computed - sorted res and exp must be equal
for i, r := range res {
e := exp[i]
if r != e {
t.Errorf("test %q, lookup %q, result %d: expected index %d; got %d", tc.name, s, i, e, r)
}
}
}
}
func testFindAllIndex(t *testing.T, tc *testCase, x *Index, rx *regexp.Regexp, n int) {
res := x.FindAllIndex(rx, n)
exp := rx.FindAllStringIndex(tc.source, n)
// check that the lengths match
if len(res) != len(exp) {
t.Errorf("test %q, FindAllIndex %q (n = %d): expected %d results; got %d", tc.name, rx, n, len(exp), len(res))
}
// if n >= 0 the number of results is limited --- unless n >= all results,
// we may obtain different positions from the Index and from regexp (because
// Index may not find the results in the same order as regexp) => in general
// we cannot simply check that the res and exp lists are equal
// check that each result is in fact a correct match and the result is sorted
for i, r := range res {
if r[0] < 0 || r[0] > r[1] || len(tc.source) < r[1] {
t.Errorf("test %q, FindAllIndex %q, result %d (n == %d): illegal match [%d, %d]", tc.name, rx, i, n, r[0], r[1])
} else if !rx.MatchString(tc.source[r[0]:r[1]]) {
t.Errorf("test %q, FindAllIndex %q, result %d (n = %d): [%d, %d] not a match", tc.name, rx, i, n, r[0], r[1])
}
}
if n < 0 {
// all results computed - sorted res and exp must be equal
for i, r := range res {
e := exp[i]
if r[0] != e[0] || r[1] != e[1] {
t.Errorf("test %q, FindAllIndex %q, result %d: expected match [%d, %d]; got [%d, %d]",
tc.name, rx, i, e[0], e[1], r[0], r[1])
}
}
}
}
func testLookups(t *testing.T, tc *testCase, x *Index, n int) {
for _, pat := range tc.patterns {
testLookup(t, tc, x, pat, n)
if rx, err := regexp.Compile(pat); err == nil {
testFindAllIndex(t, tc, x, rx, n)
}
}
}
// index is used to hide the sort.Interface
type index Index
func (x *index) Len() int { return x.sa.len() }
func (x *index) Less(i, j int) bool { return bytes.Compare(x.at(i), x.at(j)) < 0 }
func (x *index) Swap(i, j int) {
if x.sa.int32 != nil {
x.sa.int32[i], x.sa.int32[j] = x.sa.int32[j], x.sa.int32[i]
} else {
x.sa.int64[i], x.sa.int64[j] = x.sa.int64[j], x.sa.int64[i]
}
}
func (x *index) at(i int) []byte {
return x.data[x.sa.get(i):]
}
func testConstruction(t *testing.T, tc *testCase, x *Index) {
if !sort.IsSorted((*index)(x)) {
t.Errorf("failed testConstruction %s", tc.name)
}
}
func equal(x, y *Index) bool {
if !bytes.Equal(x.data, y.data) {
return false
}
if x.sa.len() != y.sa.len() {
return false
}
n := x.sa.len()
for i := 0; i < n; i++ {
if x.sa.get(i) != y.sa.get(i) {
return false
}
}
return true
}
// returns the serialized index size
func testSaveRestore(t *testing.T, tc *testCase, x *Index) int {
var buf bytes.Buffer
if err := x.Write(&buf); err != nil {
t.Errorf("failed writing index %s (%s)", tc.name, err)
}
size := buf.Len()
var y Index
if err := y.Read(bytes.NewReader(buf.Bytes())); err != nil {
t.Errorf("failed reading index %s (%s)", tc.name, err)
}
if !equal(x, &y) {
t.Errorf("restored index doesn't match saved index %s", tc.name)
}
old := maxData32
defer func() {
maxData32 = old
}()
// Reread as forced 32.
y = Index{}
maxData32 = realMaxData32
if err := y.Read(bytes.NewReader(buf.Bytes())); err != nil {
t.Errorf("failed reading index %s (%s)", tc.name, err)
}
if !equal(x, &y) {
t.Errorf("restored index doesn't match saved index %s", tc.name)
}
// Reread as forced 64.
y = Index{}
maxData32 = -1
if err := y.Read(bytes.NewReader(buf.Bytes())); err != nil {
t.Errorf("failed reading index %s (%s)", tc.name, err)
}
if !equal(x, &y) {
t.Errorf("restored index doesn't match saved index %s", tc.name)
}
return size
}
func testIndex(t *testing.T) {
for _, tc := range testCases {
x := New([]byte(tc.source))
testConstruction(t, &tc, x)
testSaveRestore(t, &tc, x)
testLookups(t, &tc, x, 0)
testLookups(t, &tc, x, 1)
testLookups(t, &tc, x, 10)
testLookups(t, &tc, x, 2e9)
testLookups(t, &tc, x, -1)
}
}
func TestIndex32(t *testing.T) {
testIndex(t)
}
func TestIndex64(t *testing.T) {
maxData32 = -1
defer func() {
maxData32 = realMaxData32
}()
testIndex(t)
}
func TestNew32(t *testing.T) {
test(t, func(x []byte) []int {
sa := make([]int32, len(x))
text_32(x, sa)
out := make([]int, len(sa))
for i, v := range sa {
out[i] = int(v)
}
return out
})
}
func TestNew64(t *testing.T) {
test(t, func(x []byte) []int {
sa := make([]int64, len(x))
text_64(x, sa)
out := make([]int, len(sa))
for i, v := range sa {
out[i] = int(v)
}
return out
})
}
// test tests an arbitrary suffix array construction function.
// Generates many inputs, builds and checks suffix arrays.
func test(t *testing.T, build func([]byte) []int) {
t.Run("ababab...", func(t *testing.T) {
// Very repetitive input has numLMS = len(x)/2-1
// at top level, the largest it can be.
// But maxID is only two (aba and ab$).
size := 100000
if testing.Short() {
size = 10000
}
x := make([]byte, size)
for i := range x {
x[i] = "ab"[i%2]
}
testSA(t, x, build)
})
t.Run("forcealloc", func(t *testing.T) {
// Construct a pathological input that forces
// recurse_32 to allocate a new temporary buffer.
// The input must have more than N/3 LMS-substrings,
// which we arrange by repeating an SLSLSLSLSLSL pattern
// like ababab... above, but then we must also arrange
// for a large number of distinct LMS-substrings.
// We use this pattern:
// 1 255 1 254 1 253 1 ... 1 2 1 255 2 254 2 253 2 252 2 ...
// This gives approximately 2¹⁵ distinct LMS-substrings.
// We need to repeat at least one substring, though,
// or else the recursion can be bypassed entirely.
x := make([]byte, 100000, 100001)
lo := byte(1)
hi := byte(255)
for i := range x {
if i%2 == 0 {
x[i] = lo
} else {
x[i] = hi
hi--
if hi <= lo {
lo++
if lo == 0 {
lo = 1
}
hi = 255
}
}
}
x[:cap(x)][len(x)] = 0 // for sais.New
testSA(t, x, build)
})
t.Run("exhaustive2", func(t *testing.T) {
// All inputs over {0,1} up to length 21.
// Runs in about 10 seconds on my laptop.
x := make([]byte, 30)
numFail := 0
for n := 0; n <= 21; n++ {
if n > 12 && testing.Short() {
break
}
x[n] = 0 // for sais.New
testRec(t, x[:n], 0, 2, &numFail, build)
}
})
t.Run("exhaustive3", func(t *testing.T) {
// All inputs over {0,1,2} up to length 14.
// Runs in about 10 seconds on my laptop.
x := make([]byte, 30)
numFail := 0
for n := 0; n <= 14; n++ {
if n > 8 && testing.Short() {
break
}
x[n] = 0 // for sais.New
testRec(t, x[:n], 0, 3, &numFail, build)
}
})
}
// testRec fills x[i:] with all possible combinations of values in [1,max]
// and then calls testSA(t, x, build) for each one.
func testRec(t *testing.T, x []byte, i, max int, numFail *int, build func([]byte) []int) {
if i < len(x) {
for x[i] = 1; x[i] <= byte(max); x[i]++ {
testRec(t, x, i+1, max, numFail, build)
}
return
}
if !testSA(t, x, build) {
*numFail++
if *numFail >= 10 {
t.Errorf("stopping after %d failures", *numFail)
t.FailNow()
}
}
}
// testSA tests the suffix array build function on the input x.
// It constructs the suffix array and then checks that it is correct.
func testSA(t *testing.T, x []byte, build func([]byte) []int) bool {
defer func() {
if e := recover(); e != nil {
t.Logf("build %v", x)
panic(e)
}
}()
sa := build(x)
if len(sa) != len(x) {
t.Errorf("build %v: len(sa) = %d, want %d", x, len(sa), len(x))
return false
}
for i := 0; i+1 < len(sa); i++ {
if sa[i] < 0 || sa[i] >= len(x) || sa[i+1] < 0 || sa[i+1] >= len(x) {
t.Errorf("build %s: sa out of range: %v\n", x, sa)
return false
}
if bytes.Compare(x[sa[i]:], x[sa[i+1]:]) >= 0 {
t.Errorf("build %v -> %v\nsa[%d:] = %d,%d out of order", x, sa, i, sa[i], sa[i+1])
return false
}
}
return true
}
var (
benchdata = make([]byte, 1e6)
benchrand = make([]byte, 1e6)
)
// Of all possible inputs, the random bytes have the least amount of substring
// repetition, and the repeated bytes have the most. For most algorithms,
// the running time of every input will be between these two.
func benchmarkNew(b *testing.B, random bool) {
b.ReportAllocs()
b.StopTimer()
data := benchdata
if random {
data = benchrand
if data[0] == 0 {
for i := range data {
data[i] = byte(rand.Intn(256))
}
}
}
b.StartTimer()
b.SetBytes(int64(len(data)))
for i := 0; i < b.N; i++ {
New(data)
}
}
func makeText(name string) ([]byte, error) {
var data []byte
switch name {
case "opticks":
var err error
data, err = ioutil.ReadFile("../../testdata/Isaac.Newton-Opticks.txt")
if err != nil {
return nil, err
}
case "go":
err := filepath.Walk("../..", func(path string, info os.FileInfo, err error) error {
if err == nil && strings.HasSuffix(path, ".go") && !info.IsDir() {
file, err := ioutil.ReadFile(path)
if err != nil {
return err
}
data = append(data, file...)
}
return nil
})
if err != nil {
return nil, err
}
case "zero":
data = make([]byte, 50e6)
case "rand":
data = make([]byte, 50e6)
for i := range data {
data[i] = byte(rand.Intn(256))
}
}
return data, nil
}
func setBits(bits int) (cleanup func()) {
if bits == 32 {
maxData32 = realMaxData32
} else {
maxData32 = -1 // force use of 64-bit code
}
return func() {
maxData32 = realMaxData32
}
}
func BenchmarkNew(b *testing.B) {
for _, text := range []string{"opticks", "go", "zero", "rand"} {
b.Run("text="+text, func(b *testing.B) {
data, err := makeText(text)
if err != nil {
b.Fatal(err)
}
if testing.Short() && len(data) > 5e6 {
data = data[:5e6]
}
for _, size := range []int{100e3, 500e3, 1e6, 5e6, 10e6, 50e6} {
if len(data) < size {
continue
}
data := data[:size]
name := fmt.Sprintf("%dK", size/1e3)
if size >= 1e6 {
name = fmt.Sprintf("%dM", size/1e6)
}
b.Run("size="+name, func(b *testing.B) {
for _, bits := range []int{32, 64} {
if ^uint(0) == 0xffffffff && bits == 64 {
continue
}
b.Run(fmt.Sprintf("bits=%d", bits), func(b *testing.B) {
cleanup := setBits(bits)
defer cleanup()
b.SetBytes(int64(len(data)))
b.ReportAllocs()
for i := 0; i < b.N; i++ {
New(data)
}
})
}
})
}
})
}
}
func BenchmarkSaveRestore(b *testing.B) {
r := rand.New(rand.NewSource(0x5a77a1)) // guarantee always same sequence
data := make([]byte, 1<<20) // 1MB of data to index
for i := range data {
data[i] = byte(r.Intn(256))
}
for _, bits := range []int{32, 64} {
if ^uint(0) == 0xffffffff && bits == 64 {
continue
}
b.Run(fmt.Sprintf("bits=%d", bits), func(b *testing.B) {
cleanup := setBits(bits)
defer cleanup()
b.StopTimer()
x := New(data)
size := testSaveRestore(nil, nil, x) // verify correctness
buf := bytes.NewBuffer(make([]byte, size)) // avoid growing
b.SetBytes(int64(size))
b.StartTimer()
b.ReportAllocs()
for i := 0; i < b.N; i++ {
buf.Reset()
if err := x.Write(buf); err != nil {
b.Fatal(err)
}
var y Index
if err := y.Read(buf); err != nil {
b.Fatal(err)
}
}
})
}
}
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