305 lines
7.2 KiB
Go
305 lines
7.2 KiB
Go
// Copyright 2010 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 suffixarray
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import (
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"bytes"
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"math/rand"
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"regexp"
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"sort"
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"strings"
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"testing"
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)
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type testCase struct {
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name string // name of test case
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source string // source to index
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patterns []string // patterns to lookup
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}
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var testCases = []testCase{
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{
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"empty string",
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"",
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[]string{
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"",
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"foo",
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"(foo)",
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".*",
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"a*",
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},
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},
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{
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"all a's",
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"aaaaaaaaaa", // 10 a's
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[]string{
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"",
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"a",
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"aa",
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"aaa",
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"aaaa",
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"aaaaa",
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"aaaaaa",
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"aaaaaaa",
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"aaaaaaaa",
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"aaaaaaaaa",
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"aaaaaaaaaa",
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"aaaaaaaaaaa", // 11 a's
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".",
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".*",
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"a+",
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"aa+",
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"aaaa[b]?",
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"aaa*",
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},
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},
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{
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"abc",
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"abc",
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[]string{
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"a",
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"b",
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"c",
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"ab",
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"bc",
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"abc",
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"a.c",
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"a(b|c)",
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"abc?",
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},
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},
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{
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"barbara*3",
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"barbarabarbarabarbara",
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[]string{
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"a",
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"bar",
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"rab",
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"arab",
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"barbar",
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"bara?bar",
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},
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},
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{
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"typing drill",
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"Now is the time for all good men to come to the aid of their country.",
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[]string{
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"Now",
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"the time",
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"to come the aid",
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"is the time for all good men to come to the aid of their",
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"to (come|the)?",
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},
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},
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{
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"godoc simulation",
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"package main\n\nimport(\n \"rand\"\n ",
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[]string{},
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},
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}
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// find all occurrences of s in source; report at most n occurrences
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func find(src, s string, n int) []int {
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var res []int
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if s != "" && n != 0 {
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// find at most n occurrences of s in src
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for i := -1; n < 0 || len(res) < n; {
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j := strings.Index(src[i+1:], s)
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if j < 0 {
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break
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}
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i += j + 1
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res = append(res, i)
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}
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}
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return res
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}
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func testLookup(t *testing.T, tc *testCase, x *Index, s string, n int) {
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res := x.Lookup([]byte(s), n)
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exp := find(tc.source, s, n)
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// check that the lengths match
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if len(res) != len(exp) {
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t.Errorf("test %q, lookup %q (n = %d): expected %d results; got %d", tc.name, s, n, len(exp), len(res))
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}
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// if n >= 0 the number of results is limited --- unless n >= all results,
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// we may obtain different positions from the Index and from find (because
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// Index may not find the results in the same order as find) => in general
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// we cannot simply check that the res and exp lists are equal
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// check that each result is in fact a correct match and there are no duplicates
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sort.Ints(res)
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for i, r := range res {
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if r < 0 || len(tc.source) <= r {
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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))
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} else if !strings.HasPrefix(tc.source[r:], s) {
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t.Errorf("test %q, lookup %q, result %d (n = %d): index %d not a match", tc.name, s, i, n, r)
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}
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if i > 0 && res[i-1] == r {
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t.Errorf("test %q, lookup %q, result %d (n = %d): found duplicate index %d", tc.name, s, i, n, r)
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}
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}
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if n < 0 {
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// all results computed - sorted res and exp must be equal
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for i, r := range res {
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e := exp[i]
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if r != e {
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t.Errorf("test %q, lookup %q, result %d: expected index %d; got %d", tc.name, s, i, e, r)
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}
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}
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}
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}
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func testFindAllIndex(t *testing.T, tc *testCase, x *Index, rx *regexp.Regexp, n int) {
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res := x.FindAllIndex(rx, n)
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exp := rx.FindAllStringIndex(tc.source, n)
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// check that the lengths match
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if len(res) != len(exp) {
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t.Errorf("test %q, FindAllIndex %q (n = %d): expected %d results; got %d", tc.name, rx, n, len(exp), len(res))
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}
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// if n >= 0 the number of results is limited --- unless n >= all results,
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// we may obtain different positions from the Index and from regexp (because
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// Index may not find the results in the same order as regexp) => in general
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// we cannot simply check that the res and exp lists are equal
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// check that each result is in fact a correct match and the result is sorted
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for i, r := range res {
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if r[0] < 0 || r[0] > r[1] || len(tc.source) < r[1] {
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t.Errorf("test %q, FindAllIndex %q, result %d (n == %d): illegal match [%d, %d]", tc.name, rx, i, n, r[0], r[1])
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} else if !rx.MatchString(tc.source[r[0]:r[1]]) {
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t.Errorf("test %q, FindAllIndex %q, result %d (n = %d): [%d, %d] not a match", tc.name, rx, i, n, r[0], r[1])
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}
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}
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if n < 0 {
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// all results computed - sorted res and exp must be equal
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for i, r := range res {
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e := exp[i]
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if r[0] != e[0] || r[1] != e[1] {
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t.Errorf("test %q, FindAllIndex %q, result %d: expected match [%d, %d]; got [%d, %d]",
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tc.name, rx, i, e[0], e[1], r[0], r[1])
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}
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}
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}
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}
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func testLookups(t *testing.T, tc *testCase, x *Index, n int) {
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for _, pat := range tc.patterns {
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testLookup(t, tc, x, pat, n)
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if rx, err := regexp.Compile(pat); err == nil {
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testFindAllIndex(t, tc, x, rx, n)
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}
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}
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}
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// index is used to hide the sort.Interface
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type index Index
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func (x *index) Len() int { return len(x.sa) }
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func (x *index) Less(i, j int) bool { return bytes.Compare(x.at(i), x.at(j)) < 0 }
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func (x *index) Swap(i, j int) { x.sa[i], x.sa[j] = x.sa[j], x.sa[i] }
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func (a *index) at(i int) []byte { return a.data[a.sa[i]:] }
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func testConstruction(t *testing.T, tc *testCase, x *Index) {
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if !sort.IsSorted((*index)(x)) {
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t.Errorf("failed testConstruction %s", tc.name)
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}
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}
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func equal(x, y *Index) bool {
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if !bytes.Equal(x.data, y.data) {
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return false
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}
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for i, j := range x.sa {
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if j != y.sa[i] {
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return false
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}
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}
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return true
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}
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// returns the serialized index size
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func testSaveRestore(t *testing.T, tc *testCase, x *Index) int {
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var buf bytes.Buffer
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if err := x.Write(&buf); err != nil {
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t.Errorf("failed writing index %s (%s)", tc.name, err)
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}
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size := buf.Len()
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var y Index
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if err := y.Read(&buf); err != nil {
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t.Errorf("failed reading index %s (%s)", tc.name, err)
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}
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if !equal(x, &y) {
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t.Errorf("restored index doesn't match saved index %s", tc.name)
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}
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return size
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}
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func TestIndex(t *testing.T) {
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for _, tc := range testCases {
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x := New([]byte(tc.source))
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testConstruction(t, &tc, x)
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testSaveRestore(t, &tc, x)
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testLookups(t, &tc, x, 0)
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testLookups(t, &tc, x, 1)
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testLookups(t, &tc, x, 10)
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testLookups(t, &tc, x, 2e9)
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testLookups(t, &tc, x, -1)
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}
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}
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// Of all possible inputs, the random bytes have the least amount of substring
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// repetition, and the repeated bytes have the most. For most algorithms,
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// the running time of every input will be between these two.
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func benchmarkNew(b *testing.B, random bool) {
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b.StopTimer()
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data := make([]byte, 1e6)
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if random {
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for i := range data {
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data[i] = byte(rand.Intn(256))
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}
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}
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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New(data)
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}
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}
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func BenchmarkNewIndexRandom(b *testing.B) {
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benchmarkNew(b, true)
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}
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func BenchmarkNewIndexRepeat(b *testing.B) {
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benchmarkNew(b, false)
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}
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func BenchmarkSaveRestore(b *testing.B) {
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b.StopTimer()
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r := rand.New(rand.NewSource(0x5a77a1)) // guarantee always same sequence
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data := make([]byte, 10<<20) // 10MB of data to index
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for i := range data {
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data[i] = byte(r.Intn(256))
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}
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x := New(data)
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size := testSaveRestore(nil, nil, x) // verify correctness
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buf := bytes.NewBuffer(make([]byte, size)) // avoid growing
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b.SetBytes(int64(size))
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b.StartTimer()
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for i := 0; i < b.N; i++ {
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x.Write(buf)
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var y Index
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y.Read(buf)
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}
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}
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