source: sourcecode/application/libraries/PHPExcel/CalcEngine/CyclicReferenceStack.php @ 1

<?php
/**
 * PHPExcel
 *
 * Copyright (c) 2006 - 2014 PHPExcel
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 *
 * @category   PHPExcel
 * @package    PHPExcel_Calculation
 * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
 * @license     http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt   LGPL
 * @version     1.8.0, 2014-03-02
 */


/**
 * PHPExcel_CalcEngine_CyclicReferenceStack
 *
 * @category    PHPExcel_CalcEngine_CyclicReferenceStack
 * @package             PHPExcel_Calculation
 * @copyright   Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
 */
class PHPExcel_CalcEngine_CyclicReferenceStack {

        /**
         *  The call stack for calculated cells
         *
         *  @var mixed[]
         */
        private $_stack = array();


        /**
         * Return the number of entries on the stack
         *
         * @return  integer
         */
        public function count() {
                return count($this->_stack);
        }

        /**
         * Push a new entry onto the stack
         *
         * @param  mixed  $value
         */
        public function push($value) {
                $this->_stack[] = $value;
        }       //      function push()

        /**
         * Pop the last entry from the stack
         *
         * @return  mixed
         */
        public function pop() {
                return array_pop($this->_stack);
        }       //      function pop()

        /**
         * Test to see if a specified entry exists on the stack
         *
         * @param  mixed  $value  The value to test
         */
        public function onStack($value) {
                return in_array($value, $this->_stack);
        }

        /**
         * Clear the stack
         */
        public function clear() {
                $this->_stack = array();
        }       //      function push()

        /**
         * Return an array of all entries on the stack
         *
         * @return  mixed[]
         */
        public function showStack() {
                return $this->_stack;
        }

}       //      class PHPExcel_CalcEngine_CyclicReferenceStack