forked from m3db/m3
/
pool.go
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/
pool.go
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// Copyright (c) 2018 Uber Technologies, Inc.
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.
package arraypool
import (
"github.com/m3db/m3/src/x/pool"
"github.com/mauricelam/genny/generic"
)
// elemType is the generic type for use with the specialized array pool.
type elemType generic.Type
// elemArrayPool provides a pool for elemType slices.
type elemArrayPool interface {
// Init initializes the array pool, it needs to be called
// before Get/Put use.
Init()
// Get returns the a slice from the pool.
Get() []elemType
// Put returns the provided slice to the pool.
Put(elems []elemType)
}
type elemFinalizeFn func([]elemType) []elemType
type elemArrayPoolOpts struct {
Options pool.ObjectPoolOptions
Capacity int
MaxCapacity int
FinalizeFn elemFinalizeFn
}
type elemArrPool struct {
opts elemArrayPoolOpts
pool pool.ObjectPool
}
// nolint
func newElemArrayPool(opts elemArrayPoolOpts) elemArrayPool {
if opts.FinalizeFn == nil {
opts.FinalizeFn = defaultElemFinalizerFn
}
p := pool.NewObjectPool(opts.Options)
return &elemArrPool{opts, p}
}
func (p *elemArrPool) Init() {
p.pool.Init(func() interface{} {
return make([]elemType, 0, p.opts.Capacity)
})
}
func (p *elemArrPool) Get() []elemType {
return p.pool.Get().([]elemType)
}
func (p *elemArrPool) Put(arr []elemType) {
arr = p.opts.FinalizeFn(arr)
if max := p.opts.MaxCapacity; max > 0 && cap(arr) > max {
return
}
p.pool.Put(arr)
}
func defaultElemFinalizerFn(elems []elemType) []elemType {
var empty elemType
for i := range elems {
elems[i] = empty
}
elems = elems[:0]
return elems
}
// nolint
type elemArr []elemType
// nolint
func (elems elemArr) grow(n int) []elemType {
if cap(elems) < n {
elems = make([]elemType, n)
}
elems = elems[:n]
// following compiler optimized memcpy impl
// https://github.com/golang/go/wiki/CompilerOptimizations#optimized-memclr
var empty elemType
for i := range elems {
elems[i] = empty
}
return elems
}