<?php

/**

 * Classes, which help reading streams of data from files.

 * Based on the classes from Danilo Segan <danilo@kvota.net>

 *

 * @package pomo

 * @subpackage streams

 */

class POMO_Reader {

	var $endian = 'little';

	var $_post = '';

		$this->is_overloaded = ((ini_get("mbstring.func_overload") & 2) != 0) && function_exists('mb_substr');

		$this->_pos = 0;

	}

	/**

	 * 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 reset( $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);

	}

	/**

	 * @param string $string

	 * @param int    $start

	 * @param int    $length

	 * @return string

	 */

	function substr($string, $start, $length) {

		if ($this->is_overloaded) {

			return mb_substr($string, $start, $length, 'ascii');

		} else {

			return substr($string, $start, $length);

		}

	}

	/**

	 * @param string $string

	 * @return int

	 */

	function strlen($string) {

		if ($this->is_overloaded) {

			return mb_strlen($string, 'ascii');

		} else {

			return strlen($string);

		}

	}

	/**

	 * @param string $string

	 * @param int    $chunk_size

	 * @return array

	 */

	function str_split($string, $chunk_size) {

		if (!function_exists('str_split')) {

			$length = $this->strlen($string);

			$out = array();

			for ($i = 0; $i < $length; $i += $chunk_size)

				$out[] = $this->substr($string, $i, $chunk_size);

			return $out;

		} else {

			return str_split( $string, $chunk_size );

		}

	}

	function pos() {

		return $this->_pos;

	}

	function is_resource() {

		return true;

	}

	function close() {

		return true;

	}

}

endif;

class POMO_FileReader extends POMO_Reader {

	/**

	 * @param string $filename

	 */

		parent::POMO_Reader();

		$this->_f = fopen($filename, 'rb');

	}

	/**

	 * @param int $bytes

	 */

	function read($bytes) {

		return fread($this->_f, $bytes);

	}

	/**

	 * @param int $pos

	 * @return boolean

	 */

	function seekto($pos) {

		if ( -1 == fseek($this->_f, $pos, SEEK_SET)) {

			return false;

		}

		$this->_pos = $pos;

		return true;

	}

	function is_resource() {

		return is_resource($this->_f);

	}

	function feof() {

		return feof($this->_f);

	}

	function close() {

		return fclose($this->_f);

	}

	function read_all() {

		$all = '';

		while ( !$this->feof() )

			$all .= $this->read(4096);

		return $all;

	}

}

endif;

/**

 * Provides file-like methods for manipulating a string instead

 * of a physical file.

 */

class POMO_StringReader extends POMO_Reader {

	var $_str = '';

		parent::POMO_Reader();

		$this->_str = $str;

		$this->_pos = 0;

	}

	/**

	 * @param string $bytes

	 * @return 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;

	}

	/**

	 * @param int $pos

	 * @return int

	 */

	function seekto($pos) {

		$this->_pos = $pos;

		if ($this->strlen($this->_str) < $this->_pos) $this->_pos = $this->strlen($this->_str);

		return $this->_pos;

	}

	function length() {

		return $this->strlen($this->_str);

	}

	function read_all() {

		return $this->substr($this->_str, $this->_pos, $this->strlen($this->_str));

	}

}

endif;

/**

 * Reads the contents of the file in the beginning.

 */

class POMO_CachedFileReader extends POMO_StringReader {

		parent::POMO_StringReader();

		$this->_str = file_get_contents($filename);

		if (false === $this->_str)

			return false;

		$this->_pos = 0;

	}

}

endif;

/**

 * Reads the contents of the file in the beginning.

 */

class POMO_CachedIntFileReader extends POMO_CachedFileReader {

		parent::POMO_CachedFileReader($filename);

	}

}