source: trunk/www.guidonia.net/wp/wp-includes/pomo/streams.php@ 44

<?php
/**
 * Classes, which help reading streams of data from files.
 * Based on the classes from Danilo Segan <danilo@kvota.net>
 *
 * @version $Id: streams.php 138 2009-06-23 13:22:09Z nbachiyski $
 * @package pomo
 * @subpackage streams
 */


/**
 * Provides file-like methods for manipulating a string instead
 * of a physical file.
 */
class POMO_StringReader {
  var $_pos;
  var $_str;

        function POMO_StringReader($str = '') {
                $this->_str = $str;
                $this->_pos = 0;
                $this->is_overloaded = ((ini_get("mbstring.func_overload") & 2) != 0) && function_exists('mb_substr');
        }

        function _substr($string, $start, $length) {
                if ($this->is_overloaded) {
                        return mb_substr($string,$start,$length,'ascii');
                } else {
                        return substr($string,$start,$length);
                }
        }
        
        function _strlen($string) {
                if ($this->is_overloaded) {
                        return mb_strlen($string,'ascii');
                } else {
                        return strlen($string);
                }
        }

        function read($bytes) {
                $data = $this->_substr($this->_str, $this->_pos, $bytes);
                $this->_pos += $bytes;
                if ($this->_strlen($this->_str) < $this->_pos) $this->_pos = $this->_strlen($this->_str);
                return $data;
        }

        function seekto($pos) {
                $this->_pos = $pos;
                if ($this->_strlen($this->_str) < $this->_pos) $this->_pos = $this->_strlen($this->_str);
                return $this->_pos;
        }

        function pos() {
                return $this->_pos;
        }

        function length() {
                return $this->_strlen($this->_str);
        }

}

/**
 * Reads the contents of the file in the beginning.
 */
class POMO_CachedFileReader extends POMO_StringReader {
        function POMO_CachedFileReader($filename) {
                parent::POMO_StringReader();
                $this->_str = file_get_contents($filename);
                if (false === $this->_str)
                        return false;
                $this->_pos = 0;
        }
}

/**
 * Allows reading integers from a file.
 */
class POMO_CachedIntFileReader extends POMO_CachedFileReader {

        var $endian = 'little';

        /**
         * Opens a file and caches it.
         *
         * @param $filename string name of the file to be opened
         * @param $endian string endianness of the words in the file, allowed
         *      values are 'little' or 'big'. Default value is 'little'
         */
        function POMO_CachedIntFileReader($filename, $endian = 'little') {
                $this->endian = $endian;
                parent::POMO_CachedFileReader($filename);
        }

        /**
         * Sets the endianness of the file.
         *
         * @param $endian string 'big' or 'little'
         */
        function setEndian($endian) {
                $this->endian = $endian;
        }

        /**
         * Reads a 32bit Integer from the Stream
         *
         * @return mixed The integer, corresponding to the next 32 bits from
         *      the stream of false if there are not enough bytes or on error
         */
        function readint32() {
                $bytes = $this->read(4);
                if (4 != $this->_strlen($bytes))
                        return false;
                $endian_letter = ('big' == $this->endian)? 'N' : 'V';
                $int = unpack($endian_letter, $bytes);
                return array_shift($int);
        }

        /**
         * Reads an array of 32-bit Integers from the Stream
         *
         * @param integer count How many elements should be read
         * @return mixed Array of integers or false if there isn't
         *      enough data or on error
         */
        function readint32array($count) {
                $bytes = $this->read(4 * $count);
                if (4*$count != $this->_strlen($bytes))
                        return false;
                $endian_letter = ('big' == $this->endian)? 'N' : 'V';
                return unpack($endian_letter.$count, $bytes);
        }
}

?>