<?php
/**
 * Classes, which help reading streams of data from files.
 * Based on the classes from Danilo Segan <danilo@kvota.net>
 *
 * @version $Id: streams.php 718 2012-10-31 00:32:02Z nbachiyski $
 * @package pomo
 * @subpackage streams
 */

if ( !class_exists( 'POMO_Reader' ) ):
class POMO_Reader {

	var $endian = 'little';
	var $_post = '';

	function __construct() {
		$this->is_overloaded = ((ini_get("mbstring.func_overload") & 2) != 0) && function_exists('mb_substr');
		$this->_pos = 0;
	}

	/**
	 * Sets the endianness of the file.
	 *
	 * @param $endian string 'big' or 'little'
	 */
	public function setEndian($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
	 */
	public 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
	 */
	public 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 );
	}


	public function substr( $string, $start, $length ) {
		if ( $this->is_overloaded ) {
			return mb_substr( $string, $start, $length, 'ascii' );
		} else {
			return substr( $string, $start, $length );
		}
	}

	public function strlen( $string ) {
		if ( $this->is_overloaded ) {
			return mb_strlen( $string, 'ascii' );
		} else {
			return strlen( $string );
		}
	}

	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 );
		}
	}


	public function pos() {
		return $this->_pos;
	}

	public function is_resource() {
		return true;
	}

	public function close() {
		return true;
	}
}
endif;

if ( !class_exists( 'POMO_FileReader' ) ):
class POMO_FileReader extends POMO_Reader {
	function __construct($filename ) {
		parent::__construct();
		$this->_f = fopen( $filename, 'rb' );
	}

	public function read( $bytes ) {
		return fread( $this->_f, $bytes );
	}

	public function seekto( $pos ) {
		if ( -1 == fseek( $this->_f, $pos, SEEK_SET ) ) {
			return false;
		}
		$this->_pos = $pos;
		return true;
	}

	public function is_resource() {
		return is_resource( $this->_f );
	}

	public function feof() {
		return feof( $this->_f );
	}

	public function close() {
		return fclose( $this->_f );
	}

	public function read_all() {
		$all = '';
		while ( !$this->feof() )
			$all .= $this->read( 4096 );
		return $all;
	}
}
endif;

if ( !class_exists( 'POMO_StringReader' ) ):
/**
 * Provides file-like methods for manipulating a string instead
 * of a physical file.
 */
class POMO_StringReader extends POMO_Reader {

	var $_str = '';

	public function __construct( $str = '' ) {
		parent::__construct();
		$this->_str = $str;
		$this->_pos = 0;
	}


	public 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;
	}

	public function seekto( $pos ) {
		$this->_pos = $pos;
		if ( $this->strlen( $this->_str ) < $this->_pos ) $this->_pos = $this->strlen( $this->_str );
		return $this->_pos;
	}

	public function length() {
		return $this->strlen( $this->_str );
	}

	public function read_all() {
		return $this->substr( $this->_str, $this->_pos, $this->strlen( $this->_str ) );
	}

}
endif;

if ( !class_exists( 'POMO_CachedFileReader' ) ):
/**
 * Reads the contents of the file in the beginning.
 */
class POMO_CachedFileReader extends POMO_StringReader {
	public function __construct( $filename ) {
		parent::__construct();
		$this->_str = file_get_contents( $filename );
		if ( false === $this->_str )
			return false;
		$this->_pos = 0;
	}
}
endif;

if ( !class_exists( 'POMO_CachedIntFileReader' ) ):
/**
 * Reads the contents of the file in the beginning.
 */
class POMO_CachedIntFileReader extends POMO_CachedFileReader {
	public function __construct( $filename ) {
		parent::__construct( $filename );
	}
}
endif;