Xray-core/common/bytespool/pool.go

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2020-11-25 11:01:53 +00:00
package bytespool
import "sync"
func createAllocFunc(size int32) func() interface{} {
return func() interface{} {
return make([]byte, size)
}
}
// The following parameters controls the size of buffer pools.
// There are numPools pools. Starting from 2k size, the size of each pool is sizeMulti of the previous one.
// Package buf is guaranteed to not use buffers larger than the largest pool.
// Other packets may use larger buffers.
const (
numPools = 4
sizeMulti = 4
)
var (
pool [numPools]sync.Pool
poolSize [numPools]int32
)
func init() {
size := int32(2048)
for i := 0; i < numPools; i++ {
pool[i] = sync.Pool{
New: createAllocFunc(size),
}
poolSize[i] = size
size *= sizeMulti
}
}
// GetPool returns a sync.Pool that generates bytes array with at least the given size.
// It may return nil if no such pool exists.
//
// xray:api:stable
func GetPool(size int32) *sync.Pool {
for idx, ps := range poolSize {
if size <= ps {
return &pool[idx]
}
}
return nil
}
// Alloc returns a byte slice with at least the given size. Minimum size of returned slice is 2048.
//
// xray:api:stable
func Alloc(size int32) []byte {
pool := GetPool(size)
if pool != nil {
return pool.Get().([]byte)
}
return make([]byte, size)
}
// Free puts a byte slice into the internal pool.
//
// xray:api:stable
func Free(b []byte) {
size := int32(cap(b))
b = b[0:cap(b)]
for i := numPools - 1; i >= 0; i-- {
if size >= poolSize[i] {
pool[i].Put(b)
return
}
}
}