<?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_Worksheet
 * @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	##VERSION##, ##DATE##
 */


/**
 * PHPExcel_Worksheet_RowCellIterator
 *
 * Used to iterate columns in a PHPExcel_Worksheet
 *
 * @category   PHPExcel
 * @package	PHPExcel_Worksheet
 * @copyright  Copyright (c) 2006 - 2014 PHPExcel (http://www.codeplex.com/PHPExcel)
 */
class PHPExcel_Worksheet_RowCellIterator extends PHPExcel_Worksheet_CellIterator implements Iterator
{
	/**
	 * Row index
	 *
	 * @var int
	 */
	protected $_rowIndex;

	/**
	 * Start position
	 *
	 * @var int
	 */
	protected $_startColumn = 0;

	/**
	 * End position
	 *
	 * @var int
	 */
	protected $_endColumn = 0;

	/**
	 * Create a new column iterator
	 *
	 * @param	PHPExcel_Worksheet	$subject	    The worksheet to iterate over
     * @param   integer             $rowIndex       The row that we want to iterate
	 * @param	string				$startColumn	The column address at which to start iterating
	 * @param	string				$endColumn	    Optionally, the column address at which to stop iterating
	 */
	public function __construct(PHPExcel_Worksheet $subject = null, $rowIndex = 1, $startColumn = 'A', $endColumn = null) {
		// Set subject and row index
		$this->_subject = $subject;
		$this->_rowIndex = $rowIndex;
		$this->resetEnd($endColumn);
		$this->resetStart($startColumn);
	}

	/**
	 * Destructor
	 */
	public function __destruct() {
		unset($this->_subject);
	}

	/**
	 * (Re)Set the start column and the current column pointer
	 *
	 * @param integer	$startColumn	The column address at which to start iterating
     * @return PHPExcel_Worksheet_RowCellIterator
     * @throws PHPExcel_Exception
	 */
	public function resetStart($startColumn = 'A') {
        $startColumnIndex = PHPExcel_Cell::columnIndexFromString($startColumn) - 1;
		$this->_startColumn = $startColumnIndex;
        $this->adjustForExistingOnlyRange();
		$this->seek(PHPExcel_Cell::stringFromColumnIndex($this->_startColumn));

        return $this;
	}

	/**
	 * (Re)Set the end column
	 *
	 * @param string	$endColumn	The column address at which to stop iterating
     * @return PHPExcel_Worksheet_RowCellIterator
     * @throws PHPExcel_Exception
	 */
	public function resetEnd($endColumn = null) {
		$endColumn = ($endColumn) ? $endColumn : $this->_subject->getHighestColumn();
		$this->_endColumn = PHPExcel_Cell::columnIndexFromString($endColumn) - 1;
        $this->adjustForExistingOnlyRange();

        return $this;
	}

	/**
	 * Set the column pointer to the selected column
	 *
	 * @param string	$column	The column address to set the current pointer at
     * @return PHPExcel_Worksheet_RowCellIterator
     * @throws PHPExcel_Exception
	 */
	public function seek($column = 'A') {
        $column = PHPExcel_Cell::columnIndexFromString($column) - 1;
        if (($column < $this->_startColumn) || ($column > $this->_endColumn)) {
            throw new PHPExcel_Exception("Column $column is out of range ({$this->_startColumn} - {$this->_endColumn})");
        } elseif ($this->_onlyExistingCells && !($this->_subject->cellExistsByColumnAndRow($column, $this->_rowIndex))) {
            throw new PHPExcel_Exception('In "IterateOnlyExistingCells" mode and Cell does not exist');
        }
		$this->_position = $column;

        return $this;
    }

	/**
	 * Rewind the iterator to the starting column
	 */
	public function rewind() {
		$this->_position = $this->_startColumn;
	}

	/**
	 * Return the current cell in this worksheet row
	 *
	 * @return PHPExcel_Cell
	 */
	public function current() {
		return $this->_subject->getCellByColumnAndRow($this->_position, $this->_rowIndex);
	}

	/**
	 * Return the current iterator key
	 *
	 * @return string
	 */
	public function key() {
		return PHPExcel_Cell::stringFromColumnIndex($this->_position);
	}

	/**
	 * Set the iterator to its next value
	 */
	public function next() {
        do {
            ++$this->_position;
        } while (($this->_onlyExistingCells) &&
            (!$this->_subject->cellExistsByColumnAndRow($this->_position, $this->_rowIndex)) &&
            ($this->_position <= $this->_endColumn));
	}

	/**
	 * Set the iterator to its previous value
     *
     * @throws PHPExcel_Exception
	 */
	public function prev() {
        if ($this->_position <= $this->_startColumn) {
            throw new PHPExcel_Exception(
                "Column is already at the beginning of range (" . 
                PHPExcel_Cell::stringFromColumnIndex($this->_endColumn) . " - " . 
                PHPExcel_Cell::stringFromColumnIndex($this->_endColumn) . ")"
            );
        }

        do {
            --$this->_position;
        } while (($this->_onlyExistingCells) &&
            (!$this->_subject->cellExistsByColumnAndRow($this->_position, $this->_rowIndex)) &&
            ($this->_position >= $this->_startColumn));
	}

	/**
	 * Indicate if more columns exist in the worksheet range of columns that we're iterating
	 *
	 * @return boolean
	 */
	public function valid() {
		return $this->_position <= $this->_endColumn;
	}

	/**
	 * Validate start/end values for "IterateOnlyExistingCells" mode, and adjust if necessary
	 *
     * @throws PHPExcel_Exception
	 */
    protected function adjustForExistingOnlyRange() {
        if ($this->_onlyExistingCells) {
            while ((!$this->_subject->cellExistsByColumnAndRow($this->_startColumn, $this->_rowIndex)) &&
                ($this->_startColumn <= $this->_endColumn)) {
                ++$this->_startColumn;
            }
            if ($this->_startColumn > $this->_endColumn) {
                throw new PHPExcel_Exception('No cells exist within the specified range');
            }
            while ((!$this->_subject->cellExistsByColumnAndRow($this->_endColumn, $this->_rowIndex)) &&
                ($this->_endColumn >= $this->_startColumn)) {
                --$this->_endColumn;
            }
            if ($this->_endColumn < $this->_startColumn) {
                throw new PHPExcel_Exception('No cells exist within the specified range');
            }
        }
    }

}