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tokenizer.go
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tokenizer.go
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package logstorage
import (
"sort"
"sync"
"unicode"
)
// tokenizeStrings extracts word tokens from a, appends them to dst and returns the result.
func tokenizeStrings(dst, a []string) []string {
t := getTokenizer()
m := t.m
for i, s := range a {
if i > 0 && s == a[i-1] {
// This string has been already tokenized
continue
}
tokenizeString(m, s)
}
dstLen := len(dst)
for k := range t.m {
dst = append(dst, k)
}
putTokenizer(t)
// Sort tokens with zero memory allocations
ss := getStringsSorter(dst[dstLen:])
sort.Sort(ss)
putStringsSorter(ss)
return dst
}
type tokenizer struct {
m map[string]struct{}
}
func (t *tokenizer) reset() {
m := t.m
for k := range m {
delete(m, k)
}
}
func tokenizeString(dst map[string]struct{}, s string) {
for len(s) > 0 {
// Search for the next token.
nextIdx := len(s)
for i, c := range s {
if isTokenRune(c) {
nextIdx = i
break
}
}
s = s[nextIdx:]
// Search for the end of the token
nextIdx = len(s)
for i, c := range s {
if !isTokenRune(c) {
nextIdx = i
break
}
}
token := s[:nextIdx]
if len(token) > 0 {
dst[token] = struct{}{}
}
s = s[nextIdx:]
}
}
func isTokenRune(c rune) bool {
return unicode.IsLetter(c) || unicode.IsDigit(c) || c == '_'
}
func getTokenizer() *tokenizer {
v := tokenizerPool.Get()
if v == nil {
return &tokenizer{
m: make(map[string]struct{}),
}
}
return v.(*tokenizer)
}
func putTokenizer(t *tokenizer) {
t.reset()
tokenizerPool.Put(t)
}
var tokenizerPool sync.Pool
type stringsSorter struct {
a []string
}
func (ss *stringsSorter) Len() int {
return len(ss.a)
}
func (ss *stringsSorter) Swap(i, j int) {
a := ss.a
a[i], a[j] = a[j], a[i]
}
func (ss *stringsSorter) Less(i, j int) bool {
a := ss.a
return a[i] < a[j]
}
func getStringsSorter(a []string) *stringsSorter {
v := stringsSorterPool.Get()
if v == nil {
return &stringsSorter{
a: a,
}
}
ss := v.(*stringsSorter)
ss.a = a
return ss
}
func putStringsSorter(ss *stringsSorter) {
ss.a = nil
stringsSorterPool.Put(ss)
}
var stringsSorterPool sync.Pool
type tokensBuf struct {
A []string
}
func (tb *tokensBuf) reset() {
a := tb.A
for i := range a {
a[i] = ""
}
tb.A = a[:0]
}
func getTokensBuf() *tokensBuf {
v := tokensBufPool.Get()
if v == nil {
return &tokensBuf{}
}
return v.(*tokensBuf)
}
func putTokensBuf(tb *tokensBuf) {
tb.reset()
tokensBufPool.Put(tb)
}
var tokensBufPool sync.Pool