68 lines
1.4 KiB
Go
68 lines
1.4 KiB
Go
/*
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* Amsterdam Web Communities System
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* Copyright (c) 2025 Erbosoft Metaverse Design Solutions, All Rights Reserved
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*
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* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this
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* file, You can obtain one at https://mozilla.org/MPL/2.0/.
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*/
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// Package util contains utility definitions.
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package util
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import "sync"
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// freeListElem is an element of the free list.
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type freeListElem[T any] struct {
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next *freeListElem[T]
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prev *freeListElem[T]
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data *T
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}
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// FreeList defines a free list.
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type FreeList[T any] struct {
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New func() *T
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mutex sync.Mutex
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listptr *freeListElem[T]
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}
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// Put adds a value to the free list.
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func (l *FreeList[T]) Put(value *T) {
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l.mutex.Lock()
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defer l.mutex.Unlock()
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ne := freeListElem[T]{data: value}
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if l.listptr == nil {
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ne.next = &ne
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ne.prev = &ne
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l.listptr = &ne
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} else {
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ne.next = l.listptr
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ne.prev = l.listptr.prev
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ne.next.prev = &ne
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ne.prev.next = &ne
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}
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}
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// Get removes a value from the free list. If there are no values and New is specified, is calls that.
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func (l *FreeList[T]) Get() *T {
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l.mutex.Lock()
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defer l.mutex.Unlock()
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var rc *T = nil
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if l.listptr == nil {
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if l.New != nil {
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rc = l.New()
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}
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} else {
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elt := l.listptr
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rc = elt.data
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l.listptr = elt.next
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if l.listptr == elt {
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l.listptr = nil
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} else {
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elt.prev.next = elt.next
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elt.next.prev = elt.prev
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}
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}
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return rc
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}
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