85 lines
2.1 KiB
PHP
85 lines
2.1 KiB
PHP
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<?php
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/**
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* Useful PHP Basics
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* Copyright (C) 2023 Sebastian Meyer <sebastian.meyer@opencultureconsulting.com>
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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declare(strict_types=1);
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namespace OCC\Basics\DataStructures;
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use Countable;
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use Iterator;
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use Serializable;
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/**
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* A (type-sensitive) destructive First In, First Out Queue.
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*
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* @author Sebastian Meyer <sebastian.meyer@opencultureconsulting.com>
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* @package opencultureconsulting/basics
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* @implements \Countable
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* @implements \Iterator
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* @implements \Serializable
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*/
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class StrictQueue extends AbstractStrictList
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{
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/**
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* Get and remove the first item.
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* @see Iterator::current
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*
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* @return mixed The first item or NULL if empty
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*/
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public function current(): mixed
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{
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return array_shift($this->items);
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}
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/**
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* Dequeue the first item.
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* Alias of Queue::current
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*
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* @return mixed The first item or NULL if empty
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*/
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public function dequeue(): mixed
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{
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return $this->current();
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}
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/**
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* Enqueue items.
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* Alias of Queue::append
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*
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* @param mixed ...$items One or more items to add
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*
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* @return void
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*/
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public function enqueue(mixed ...$items): void
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{
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$this->append(...$items);
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}
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/**
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* Get the first item without removing it.
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*
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* @return mixed The first item or NULL if empty
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*/
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public function peek(): mixed
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{
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return $this->items[array_key_first($this->items)] ?? null;
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}
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}
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