<?php
/*
 * FCKeditor - The text editor for Internet - http://www.fckeditor.net
 * Copyright (C) 2003-2007 Frederico Caldeira Knabben
 *
 * == BEGIN LICENSE ==
 *
 * Licensed under the terms of any of the following licenses at your
 * choice:
 *
 *  - GNU General Public License Version 2 or later (the "GPL")
 *    http://www.gnu.org/licenses/gpl.html
 *
 *  - GNU Lesser General Public License Version 2.1 or later (the "LGPL")
 *    http://www.gnu.org/licenses/lgpl.html
 *
 *  - Mozilla Public License Version 1.1 or later (the "MPL")
 *    http://www.mozilla.org/MPL/MPL-1.1.html
 *
 * == END LICENSE ==
 *
 * Utility functions for the File Manager Connector for PHP.
 */

function RemoveFromStart( $sourceString, $charToRemove )
{
	$sPattern = '|^' . $charToRemove . '+|' ;
	return preg_replace( $sPattern, '', $sourceString ) ;
}

function RemoveFromEnd( $sourceString, $charToRemove )
{
	$sPattern = '|' . $charToRemove . '+$|' ;
	return preg_replace( $sPattern, '', $sourceString ) ;
}

function ConvertToXmlAttribute( $value )
{
	if ( defined( 'PHP_OS' ) ) 
	{
		$os = PHP_OS ;
	}
	else
	{
		$os = php_uname() ;
	}
	
	if ( strtoupper( substr( $os, 0, 3 ) ) === 'WIN' ) 
	{
		return ( utf8_encode( htmlspecialchars( $value ) ) ) ;
	} 
	else 
	{
		return ( htmlspecialchars( $value ) ) ;
	}	
}

/**
 * Detect HTML in the first KB to prevent against potential security issue with 
 * IE/Safari/Opera file type auto detection bug.
 * Returns true if file contain insecure HTML code at the beginning.
 * 
 * @param string $filePath absolute path to file
 * @return boolean
 */ 
function DetectHtml( $filePath )
{
	$fp = fopen( $filePath, 'rb' ) ;
	$chunk = fread( $fp, 1024 ) ;
	fclose( $fp ) ;

	$chunk = strtolower( $chunk ) ;

	if (!$chunk) 
	{
		return false ;
	}

	$chunk = trim( $chunk ) ;

	if ( preg_match( "/<!DOCTYPE\W*X?HTML/sim", $chunk ) ) 
	{
		return true;
	}	

	$tags = array( '<body', '<head', '<html', '<img', '<pre', '<script', '<table', '<title' ) ;

	foreach( $tags as $tag ) 
	{
		if( false !== strpos( $chunk, $tag ) ) 
		{
			return true ;
		}
	}

	//type = javascript
	if ( preg_match( '!type\s*=\s*[\'"]?\s*(?:\w*/)?(?:ecma|java)!sim', $chunk ) ) 
	{
		return true ;
	}

	//href = javascript
	//src = javascript
	//data = javascript
	if ( preg_match( '!(?:href|src|data)\s*=\s*[\'"]?\s*(?:ecma|java)script:!sim', $chunk ) )
	{
		return true ;
	}
	
	//url(javascript
	if ( preg_match( '!url\s*\(\s*[\'"]?\s*(?:ecma|java)script:!sim', $chunk ) ) 
	{
		return true ;
	}			

	return false ;	
}

/**
 * Check file content.
 * Currently this function validates only image files.
 * Returns false if file is invalid.
 * 
 * @param string $filePath absolute path to file
 * @param string $extension file extension
 * @param integer $detectionLevel 0 = none, 1 = use getimagesize for images, 2 = use DetectHtml for images
 * @return boolean
 */ 
function IsFileValid( $filePath, $extension, $detectionLevel )
{
	if ( $detectionLevel <= 0 ) {
		return true;
	}

	$imageCheckExtensions = array('gif', 'jpeg', 'jpg', 'png', 'swf', 'psd', 'bmp', 'iff');

	// version_compare is available since PHP4 >= 4.0.7
	if ( function_exists( 'version_compare' ) ) {
		$sCurrentVersion = phpversion();
		if ( version_compare( $sCurrentVersion, "4.2.0" ) >= 0 ) {
			$imageCheckExtensions[] = "tiff";
			$imageCheckExtensions[] = "tif";
		}
		if ( version_compare( $sCurrentVersion, "4.3.0" ) >= 0 ) {
			$imageCheckExtensions[] = "swc";
		}
		if ( version_compare( $sCurrentVersion, "4.3.2" ) >= 0 ) {
			$imageCheckExtensions[] = "jpc";
			$imageCheckExtensions[] = "jp2";
			$imageCheckExtensions[] = "jpx";
			$imageCheckExtensions[] = "jb2";
			$imageCheckExtensions[] = "xbm";
			$imageCheckExtensions[] = "wbmp";
		}
	}
	
	if ( !in_array( $extension, $imageCheckExtensions ) ) {
		return true;
	}
	
	if ( $detectionLevel >= 1) {
		if ( @getimagesize( $filePath ) === false ) {
			return false ;
		}		
	}
	
	if ( $detectionLevel >= 2) {
		if ( DetectHtml( $filePath ) ) {
			return false;
		}
	}	
	
	return true;
}

?>