glob/match/match.go

135 lines
2.0 KiB
Go

package match
import (
"fmt"
"strings"
"sync"
)
const lenOne = 1
const lenZero = 0
const lenNo = -1
type Matcher interface {
Match(string) bool
Index(string, []int) (int, []int)
Len() int
String() string
}
type Matchers []Matcher
func (m Matchers) String() string {
var s []string
for _, matcher := range m {
s = append(s, fmt.Sprint(matcher))
}
return fmt.Sprintf("%s", strings.Join(s, ","))
}
var segmentsPools [1024]sync.Pool
func toPowerOfTwo(v int) int {
v--
v |= v >> 1
v |= v >> 2
v |= v >> 4
v |= v >> 8
v |= v >> 16
v++
return v
}
const (
minSegment = 32
minSegmentMinusOne = 31
maxSegment = 1024
maxSegmentMinusOne = 1023
)
func init() {
for i := maxSegment; i >= minSegment; i >>= 1 {
func(i int) {
segmentsPools[i-1] = sync.Pool{
New: func() interface{} {
return make([]int, 0, i)
},
}
}(i)
}
}
func getIdx(c int) int {
p := toPowerOfTwo(c)
switch {
case p >= maxSegment:
return maxSegmentMinusOne
case p <= minSegment:
return minSegmentMinusOne
default:
return p - 1
}
}
func acquireSegments(c int) []int {
return segmentsPools[getIdx(c)].Get().([]int)[:0]
}
func releaseSegments(s []int) {
segmentsPools[getIdx(cap(s))].Put(s)
}
// appendMerge merges and sorts given already SORTED and UNIQUE segments.
func appendMerge(target, sub []int) []int {
lt, ls := len(target), len(sub)
out := acquireSegments(lt + ls)
for x, y := 0, 0; x < lt || y < ls; {
if x >= lt {
out = append(out, sub[y:]...)
break
}
if y >= ls {
out = append(out, target[x:]...)
break
}
xValue := target[x]
yValue := sub[y]
switch {
case xValue == yValue:
out = append(out, xValue)
x++
y++
case xValue < yValue:
out = append(out, xValue)
x++
case yValue < xValue:
out = append(out, yValue)
y++
}
}
target = append(target[:0], out...)
releaseSegments(out)
return target
}
func reverseSegments(input []int) {
l := len(input)
m := l / 2
for i := 0; i < m; i++ {
input[i], input[l-i-1] = input[l-i-1], input[i]
}
}