forked from gitea/gitea
92 lines
1.4 KiB
Go
92 lines
1.4 KiB
Go
package match
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import (
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"sync"
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)
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type SomePool interface {
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Get() []int
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Put([]int)
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}
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var segmentsPools [1024]sync.Pool
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func toPowerOfTwo(v int) int {
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v--
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v |= v >> 1
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v |= v >> 2
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v |= v >> 4
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v |= v >> 8
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v |= v >> 16
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v++
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return v
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}
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const (
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cacheFrom = 16
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cacheToAndHigher = 1024
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cacheFromIndex = 15
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cacheToAndHigherIndex = 1023
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)
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var (
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segments0 = []int{0}
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segments1 = []int{1}
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segments2 = []int{2}
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segments3 = []int{3}
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segments4 = []int{4}
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)
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var segmentsByRuneLength [5][]int = [5][]int{
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0: segments0,
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1: segments1,
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2: segments2,
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3: segments3,
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4: segments4,
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}
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func init() {
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for i := cacheToAndHigher; i >= cacheFrom; i >>= 1 {
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func(i int) {
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segmentsPools[i-1] = sync.Pool{New: func() interface{} {
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return make([]int, 0, i)
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}}
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}(i)
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}
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}
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func getTableIndex(c int) int {
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p := toPowerOfTwo(c)
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switch {
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case p >= cacheToAndHigher:
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return cacheToAndHigherIndex
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case p <= cacheFrom:
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return cacheFromIndex
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default:
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return p - 1
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}
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}
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func acquireSegments(c int) []int {
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// make []int with less capacity than cacheFrom
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// is faster than acquiring it from pool
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if c < cacheFrom {
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return make([]int, 0, c)
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}
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return segmentsPools[getTableIndex(c)].Get().([]int)[:0]
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}
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func releaseSegments(s []int) {
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c := cap(s)
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// make []int with less capacity than cacheFrom
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// is faster than acquiring it from pool
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if c < cacheFrom {
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return
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}
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segmentsPools[getTableIndex(c)].Put(s)
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}
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