<?php

/**

 * Zend Framework

 *

 * LICENSE

 *

 * This source file is subject to the new BSD license that is bundled

 * with this package in the file LICENSE.txt.

 * It is also available through the world-wide-web at this URL:

 * http://framework.zend.com/license/new-bsd

 * If you did not receive a copy of the license and are unable to

 * obtain it through the world-wide-web, please send an email

 * to license@zend.com so we can send you a copy immediately.

 *

 * @category   Zend

 * @package    Zend_Search_Lucene

 * @subpackage Storage

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 * @version    $Id: Filesystem.php 23395 2010-11-19 15:30:47Z alexander $

 */

/** Zend_Search_Lucene_Storage_File */

require_once 'Zend/Search/Lucene/Storage/File.php';

/**

 * @category   Zend

 * @package    Zend_Search_Lucene

 * @subpackage Storage

 * @copyright  Copyright (c) 2005-2010 Zend Technologies USA Inc. (http://www.zend.com)

 * @license    http://framework.zend.com/license/new-bsd     New BSD License

 */

class Zend_Search_Lucene_Storage_File_Filesystem extends Zend_Search_Lucene_Storage_File

{

    /**

     * Resource of the open file

     *

     * @var resource

     */

    protected $_fileHandle;

    /**

     * Class constructor.  Open the file.

     *

     * @param string $filename

     * @param string $mode

     */

    public function __construct($filename, $mode='r+b')

    {

        global $php_errormsg;

        if (strpos($mode, 'w') === false  &&  !is_readable($filename)) {

            // opening for reading non-readable file

            require_once 'Zend/Search/Lucene/Exception.php';

            throw new Zend_Search_Lucene_Exception('File \'' . $filename . '\' is not readable.');

        }

        $trackErrors = ini_get('track_errors');

        ini_set('track_errors', '1');

        $this->_fileHandle = @fopen($filename, $mode);

        if ($this->_fileHandle === false) {

            ini_set('track_errors', $trackErrors);

            require_once 'Zend/Search/Lucene/Exception.php';

            throw new Zend_Search_Lucene_Exception($php_errormsg);

        }

        ini_set('track_errors', $trackErrors);

    }

    /**

     * Sets the file position indicator and advances the file pointer.

     * The new position, measured in bytes from the beginning of the file,

     * is obtained by adding offset to the position specified by whence,

     * whose values are defined as follows:

     * SEEK_SET - Set position equal to offset bytes.

     * SEEK_CUR - Set position to current location plus offset.

     * SEEK_END - Set position to end-of-file plus offset. (To move to

     * a position before the end-of-file, you need to pass a negative value

     * in offset.)

     * SEEK_CUR is the only supported offset type for compound files

     *

     * Upon success, returns 0; otherwise, returns -1

     *

     * @param integer $offset

     * @param integer $whence

     * @return integer

     */

    public function seek($offset, $whence=SEEK_SET)

    {

        return fseek($this->_fileHandle, $offset, $whence);

    }

    /**

     * Get file position.

     *

     * @return integer

     */

    public function tell()

    {

        return ftell($this->_fileHandle);

    }

    /**

     * Flush output.

     *

     * Returns true on success or false on failure.

     *

     * @return boolean

     */

    public function flush()

    {

        return fflush($this->_fileHandle);

    }

    /**

     * Close File object

     */

    public function close()

    {

        if ($this->_fileHandle !== null ) {

            @fclose($this->_fileHandle);

            $this->_fileHandle = null;

        }

    }

    /**

     * Get the size of the already opened file

     *

     * @return integer

     */

    public function size()

    {

        $position = ftell($this->_fileHandle);

        fseek($this->_fileHandle, 0, SEEK_END);

        $size = ftell($this->_fileHandle);

        fseek($this->_fileHandle,$position);

        return $size;

    }

    /**

     * Read a $length bytes from the file and advance the file pointer.

     *

     * @param integer $length

     * @return string

     */

    protected function _fread($length=1)

    {

        if ($length == 0) {

            return '';

        }

        if ($length < 1024) {

            return fread($this->_fileHandle, $length);

        }

        $data = '';

        while ($length > 0 && !feof($this->_fileHandle)) {

            $nextBlock = fread($this->_fileHandle, $length);

            if ($nextBlock === false) {

                require_once 'Zend/Search/Lucene/Exception.php';

                throw new Zend_Search_Lucene_Exception( "Error occured while file reading." );

            }

            $data .= $nextBlock;

            $length -= strlen($nextBlock);

        }

        if ($length != 0) {

            require_once 'Zend/Search/Lucene/Exception.php';

            throw new Zend_Search_Lucene_Exception( "Error occured while file reading." );

        }

        return $data;

    }

    /**

     * Writes $length number of bytes (all, if $length===null) to the end

     * of the file.

     *

     * @param string $data

     * @param integer $length

     */

    protected function _fwrite($data, $length=null)

    {

        if ($length === null ) {

            fwrite($this->_fileHandle, $data);

        } else {

            fwrite($this->_fileHandle, $data, $length);

        }

    }

    /**

     * Lock file

     *

     * Lock type may be a LOCK_SH (shared lock) or a LOCK_EX (exclusive lock)

     *

     * @param integer $lockType

     * @param boolean $nonBlockingLock

     * @return boolean

     */

    public function lock($lockType, $nonBlockingLock = false)

    {

        if ($nonBlockingLock) {

            return flock($this->_fileHandle, $lockType | LOCK_NB);

        } else {

            return flock($this->_fileHandle, $lockType);

        }

    }

    /**

     * Unlock file

     *

     * Returns true on success

     *

     * @return boolean

     */

    public function unlock()

    {

        if ($this->_fileHandle !== null ) {

            return flock($this->_fileHandle, LOCK_UN);

        } else {

            return true;

        }

    }

}