memory.php

很棒的在线教学系统

<?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 [e-mail] so we can send you a copy immediately.
 *
 * @category   Zend
 * @package    Zend_Search_Lucene
 * @subpackage Storage
 * @copyright  Copyright (c) 2005-2008 Zend Technologies USA Inc. (http://www.zend.com)
 * @license    http://framework.zend.com/license/new-bsd     New BSD License
 */


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

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


/**
 * @category   Zend
 * @package    Zend_Search_Lucene
 * @subpackage Storage
 * @copyright  Copyright (c) 2005-2008 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_Memory extends Zend_Search_Lucene_Storage_File
{
    /**
     * FileData
     *
     * @var string
     */
    private $_data;

    /**
     * File Position
     *
     * @var integer
     */
    private $_position = 0;


    /**
     * Object constractor
     *
     * @param string $data
     */
    public function __construct($data)
    {
        $this->_data = $data;
    }

    /**
     * Reads $length number of bytes at the current position in the
     * file and advances the file pointer.
     *
     * @param integer $length
     * @return string
     */
    protected function _fread($length = 1)
    {
        $returnValue = substr($this->_data, $this->_position, $length);
        $this->_position += $length;
        return $returnValue;
    }


    /**
     * 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.)
     * Upon success, returns 0; otherwise, returns -1
     *
     * @param integer $offset
     * @param integer $whence
     * @return integer
     */
    public function seek($offset, $whence=SEEK_SET)
    {
        switch ($whence) {
            case SEEK_SET:
                $this->_position = $offset;
                break;

            case SEEK_CUR:
                $this->_position += $offset;
                break;

            case SEEK_END:
                $this->_position = strlen($this->_data);
                $this->_position += $offset;
                break;

            default:
                break;
        }
    }

    /**
     * Get file position.
     *
     * @return integer
     */
    public function tell()
    {
        return $this->_position;
    }

    /**
     * Flush output.
     *
     * Returns true on success or false on failure.
     *
     * @return boolean
     */
    public function flush()
    {
        // Do nothing

        return true;
    }

    /**
     * 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)
    {
        // We do not need to check if file position points to the end of "file".
        // Only append operation is supported now

        if ($length !== null) {
            $this->_data .= substr($data, 0, $length);
        } else {
            $this->_data .= $data;
        }

        $this->_position = strlen($this->_data);
    }

    /**
     * Lock file
     *
     * Lock type may be a LOCK_SH (shared lock) or a LOCK_EX (exclusive lock)
     *
     * @param integer $lockType
     * @return boolean
     */
    public function lock($lockType, $nonBlockinLock = false)
    {
        // Memory files can't be shared
        // do nothing

        return true;
    }

    /**
     * Unlock file
     */
    public function unlock()
    {
        // Memory files can't be shared
        // do nothing
    }

    /**
     * Reads a byte from the current position in the file
     * and advances the file pointer.
     *
     * @return integer
     */
    public function readByte()
    {
        return ord($this->_data[$this->_position++]);
    }

    /**
     * Writes a byte to the end of the file.
     *
     * @param integer $byte
     */
    public function writeByte($byte)
    {
        // We do not need to check if file position points to the end of "file".
        // Only append operation is supported now

        $this->_data .= chr($byte);
        $this->_position = strlen($this->_data);

        return 1;
    }

    /**
     * Read num bytes from the current position in the file
     * and advances the file pointer.
     *
     * @param integer $num
     * @return string
     */
    public function readBytes($num)
    {
        $returnValue = substr($this->_data, $this->_position, $num);
        $this->_position += $num;

        return $returnValue;
    }

    /**
     * Writes num bytes of data (all, if $num===null) to the end
     * of the string.
     *
     * @param string $data
     * @param integer $num
     */
    public function writeBytes($data, $num=null)
    {
        // We do not need to check if file position points to the end of "file".
        // Only append operation is supported now

        if ($num !== null) {
            $this->_data .= substr($data, 0, $num);
        } else {
            $this->_data .= $data;
        }

        $this->_position = strlen($this->_data);
    }


    /**
     * Reads an integer from the current position in the file
     * and advances the file pointer.
     *
     * @return integer
     */
    public function readInt()
    {
        $str = substr($this->_data, $this->_position, 4);
        $this->_position += 4;

        return  ord($str{0}) << 24 |
                ord($str{1}) << 16 |
                ord($str{2}) << 8  |
                ord($str{3});
    }


    /**
     * Writes an integer to the end of file.
     *
     * @param integer $value
     */
    public function writeInt($value)
    {
        // We do not need to check if file position points to the end of "file".
        // Only append operation is supported now

        settype($value, 'integer');