minio/pkg/bpool/bpool.go

70 lines
1.8 KiB
Go

/*
* Minio Cloud Storage, (C) 2016 Minio, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
// Package bpool implements a fixed size pool of byte slices.
package bpool
import (
"errors"
"sync"
)
// ErrBpoolNoFree - Normally this error should never be returned, this error
// indicates a bug in the package consumer.
var ErrBpoolNoFree = errors.New("no free byte slice in pool")
// BytePool - temporary pool of byte slices.
type BytePool struct {
buf [][]byte // array of byte slices
used []bool // indicates if a buf[i] is in use
size int64 // size of buf[i]
mu sync.Mutex
}
// Get - Returns an unused byte slice.
func (b *BytePool) Get() (buf []byte, err error) {
b.mu.Lock()
defer b.mu.Unlock()
for i := 0; i < len(b.used); i++ {
if !b.used[i] {
b.used[i] = true
if b.buf[i] == nil {
b.buf[i] = make([]byte, b.size)
}
return b.buf[i], nil
}
}
return nil, ErrBpoolNoFree
}
// Reset - Marks all slices as unused.
func (b *BytePool) Reset() {
b.mu.Lock()
defer b.mu.Unlock()
for i := 0; i < len(b.used); i++ {
b.used[i] = false
}
}
// NewBytePool - Returns new pool.
// size - length of each slice.
// n - number of slices in the pool.
func NewBytePool(size int64, n int) *BytePool {
used := make([]bool, n)
buf := make([][]byte, n)
return &BytePool{buf, used, size, sync.Mutex{}}
}