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vsphere-influxdb-go/vendor/github.com/influxdata/influxdb/pkg/pool/bytes.go
2017-10-25 20:52:40 +00:00

101 lines
2.4 KiB
Go

// Package pool provides pool structures to help reduce garbage collector pressure.
package pool
// Bytes is a pool of byte slices that can be re-used. Slices in
// this pool will not be garbage collected when not in use.
type Bytes struct {
pool chan []byte
}
// NewBytes returns a Bytes pool with capacity for max byte slices
// to be pool.
func NewBytes(max int) *Bytes {
return &Bytes{
pool: make(chan []byte, max),
}
}
// Get returns a byte slice size with at least sz capacity. Items
// returned may not be in the zero state and should be reset by the
// caller.
func (p *Bytes) Get(sz int) []byte {
var c []byte
select {
case c = <-p.pool:
default:
return make([]byte, sz)
}
if cap(c) < sz {
return make([]byte, sz)
}
return c[:sz]
}
// Put returns a slice back to the pool. If the pool is full, the byte
// slice is discarded.
func (p *Bytes) Put(c []byte) {
select {
case p.pool <- c:
default:
}
}
// LimitedBytes is a pool of byte slices that can be re-used. Slices in
// this pool will not be garbage collected when not in use. The pool will
// hold onto a fixed number of byte slices of a maximum size. If the pool
// is empty and max pool size has not been allocated yet, it will return a
// new byte slice. Byte slices added to the pool that are over the max size
// are dropped.
type LimitedBytes struct {
allocated int64
maxSize int
pool chan []byte
}
// NewBytes returns a Bytes pool with capacity for max byte slices
// to be pool.
func NewLimitedBytes(capacity int, maxSize int) *LimitedBytes {
return &LimitedBytes{
pool: make(chan []byte, capacity),
maxSize: maxSize,
}
}
// Get returns a byte slice size with at least sz capacity. Items
// returned may not be in the zero state and should be reset by the
// caller.
func (p *LimitedBytes) Get(sz int) []byte {
var c []byte
// If we have not allocated our capacity, return a new allocation,
// otherwise block until one frees up.
select {
case c = <-p.pool:
default:
return make([]byte, sz)
}
if cap(c) < sz {
return make([]byte, sz)
}
return c[:sz]
}
// Put returns a slice back to the pool. If the pool is full, the byte
// slice is discarded. If the byte slice is over the configured max size
// of any byte slice in the pool, it is discared.
func (p *LimitedBytes) Put(c []byte) {
// Drop buffers that are larger than the max size
if cap(c) >= p.maxSize {
return
}
select {
case p.pool <- c:
default:
}
}