path: root/includes/classes/KernelTools.php

<?php
/**
 * @version $Header$
 * @package kernel
 * @subpackage functions
 */
namespace Bitweaver;

define( 'EMAIL_ADDRESS_REGEX', '[-a-zA-Z0-9._%+]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{2,4}' );

class KernelTools
{

	public function __construct() {
		mb_internal_encoding( "UTF-8" );

	}

	/**
	 * Return system defined temporary directory.
	 * In Unix, this is usually /tmp
	 * In Windows, this is usually c:\windows\temp or c:\winnt\temp
	 *
	 * @access public
	 * @return bool|string system defined temporary directory.
	 */
	public static function get_temp_dir():bool|string {
		static $tempdir;
		if( !$tempdir ) {
			global $gTempDir;
			if( !empty( $gTempDir ) ) {
				$tempdir = $gTempDir;
			} else {
				if( !KernelTools::is_windows() ) {
					$tempfile = tempnam( @ini_get( 'safe_mode'
								? $_SERVER['DOCUMENT_ROOT'] . '/temp/'
								: false, ),'foo' );
					$tempdir = dirname( $tempfile );
					@unlink( $tempfile );
				} else {
					$tempdir = getenv( "TMP" );
				}
			}
		}
		return $tempdir;
	}

	/**
	 * is_windows
	 *
	 * @access public
	 * @return bool true if we are on windows, false otherwise
	 */
	public static function is_windows(): bool {
		static $sWindows;
		if( !isset( $sWindows )) {
			$sWindows = substr( PHP_OS, 0, 3 ) == 'WIN';
		}
		return $sWindows;
	}

	/**
	 * Determines if file exists and is non zero
	 *
	 * @param string $pFile target file
	 * @access public
	 * @return bool true if file exists and is non zero, false on failure
	 */
	public static function file_valid( $pFile ) {
		return file_exists( $pFile ) && filesize( $pFile );
	}

	/**
	 * Return an integer with a signed 32 bit max value 
	 *
	 * @param int $pInt native PHP integer, may or may not be greater than 2^32
	 * @access public
	 * @return number less than 32
	 */
	public static function int32( $pInt ) {
		return (int)$pInt & 0xFFFFFFFF;
	}

	/**
	 * Recursively create directories
	 *
	 * @param string $pTarget target directory
	 * @param float $pPerms octal permissions
	 * @access public
	 * @return bool true on success, false on failure - mErrors will contain reason for failure
	 */
	public static function mkdir_p( string $pTarget, float $pPerms = 0755 ): bool {
		// clean up input
		$pTarget = str_replace( "//", "/", trim( $pTarget ));

		if( empty( $pTarget ) || $pTarget == ';' || $pTarget == "/" ) {
			return false;
		}

		if( ini_get( 'safe_mode' )) {
			$pTarget = preg_replace( '/^\/tmp/', $_SERVER['DOCUMENT_ROOT'].'/temp', $pTarget );
		}

		if( file_exists( $pTarget ) ) {
			return is_dir( $pTarget );
		}

		if( !KernelTools::is_windows() ) {
			if( substr( $pTarget, 0, 1 ) != '/' ) {
				$pTarget = "/$pTarget";
			}

			if( preg_match( '#\.\.#', $pTarget )) {
				bitdebug( "mkdir_p() - We don't allow '..' in path for security reasons: $pTarget" );
				return false;
			}
		}
		$oldu = umask( 0 );
		@mkdir( $pTarget, $pPerms, true );
		umask( $oldu );

		return true;
	}

	/**
	 * check to see if particular directories are wroteable by bitweaver
	 * added check for Windows - wolff_borg - see http://bugs.php.net/bug.php?id=27609
	 *
	 * @param string $pPath path to file or dir
	 * @access public
	 * @return bool true on success, false on failure
	 */
	public static function bw_is_writeable( $pPath ): bool {
		if( !KernelTools::is_windows() ) {
			return is_writeable( $pPath );
		}
			$writeable = false;
			if( is_dir( $pPath )) {
				$rnd = rand();
				$writeable = @fopen( $pPath."/".$rnd, "a" );
				if( $writeable ) {
					fclose( $writeable );
					unlink( $pPath."/".$rnd );
					$writeable = true;
				}
			} else {
				$writeable = @fopen( $pPath,"a" );
				if( $writeable ) {
					fclose( $writeable );
					$writeable = true;
				}
			}
			return $writeable;

	}

	/**
	 * clean up an array of values and remove any dangerous html - particularly useful for cleaning up $_GET and $_REQUEST.
	 * Turn off urldecode when detoxifying $_GET or $_REQUEST - these two are always urldecoded done by PHP itself (check docs).
	 * If you urldecode $_GET twice there might be unexpected consequences (like page One%2BTwo --(PHP)--> One+Two --(you)--> One Two).
	 *
	 * @param array $pParamHash array to be cleaned
	 * @param bool $pHtml set true to escape HTML code as well
	 * @param bool $pUrldecode set true to urldecode as well
	 * @access public
	 * @return void
	 */
	public static function detoxify( array &$pParamHash, bool $pHtml = false, bool $pUrldecode = true): void {
		if( !empty( $pParamHash ) && is_array( $pParamHash ) ) {
			foreach( $pParamHash as $key => $value ) {
				if( isset( $value ) && is_array( $value ) ) {
					KernelTools::detoxify( $value, $pHtml, $pUrldecode );
				} else {
					if( $pHtml ) {
						$newValue = $pUrldecode ? urldecode( $value ) : $value;
						$pParamHash[$key] = htmlspecialchars( $newValue, ENT_NOQUOTES );
					} elseif( preg_match( "/<script[^>]*>/i", urldecode( $value ?? '' ) ) ) {
						unset( $pParamHash[$key] );
					}
				}
			}
		}
	}

	/**
	 * file_name_to_title
	 *
	 * @param string $pFileName
	 * @access public
	 * @return string clean file name that can be used as title
	 */
	public static function file_name_to_title( $pFileName ): string {
		if( preg_match( '/^[A-Z]:\\\/', $pFileName ) ) {
				// MSIE shit file names if passthrough via gigaupload, etc.
				// basename will not work - see http://us3.php.net/manual/en/function.basename.php
				$tmp = preg_split("[\\\]",$pFileName);
				$defaultName = $tmp[count($tmp) - 1];
		} elseif( strpos( '.', $pFileName ) ) {
				list( $defaultName, $ext ) = explode( '.', $pFileName );
		} else {
				$defaultName = $pFileName;
		}
		return str_replace(  '_', ' ', substr( $defaultName, 0, strrpos( $defaultName, '.' ) ) );
	}

	/**
	 * path_to_url
	 *
	 * @param string $pPath Relative path starting in the bitweaver root directory
	 * @access public
	 * @return string A valid url based on the given path
	 */
	public static function storage_path_to_url( $pPath ) {
		global $gBitSystem;
		return STORAGE_HOST_URI.STORAGE_PKG_URL.str_replace( '//', '/', str_replace( '+', '%20', str_replace( '%2F', '/', urlencode( $pPath ))));
	}

	/**
	 * simple function to include in deprecated function calls. makes the developer replace with newer code
	 *
	 * @param string $pReplace code that needs replacing
	 * @return void
	 */
	public static function deprecated( ?string $pReplace = null ): void {
		$trace = debug_backtrace();
			$function = !empty( $trace[1]['class'] ) ? $trace[1]['class']."::".$trace[1]['function'] : $trace[1]['function'];
		$out = "Deprecated function call:\n\tfunction: $function()\n\tfile: ".$trace[1]['file']."\n\tline: ".$trace[1]['line'];

		if( !empty( $pReplace ) ) {
			$out .= "\n\t".str_replace( "\n", "\n\t", $pReplace );
		}

		if( !defined( 'IS_LIVE' ) || IS_LIVE == false ) {
			vd( $out, false, true );
		} else {
			error_log( $out );
		}
	}

	/**
	 * Check that function is enabled on server.
	 * @access public
	 * @return bool true if function is enabled on server, false otherwise
	 */
	public static function function_enabled ( $pName ) {
		static $disabled = null;

		if( $disabled == null ) {
			$functions = @ini_get( 'disable_functions' );
			$functions = str_replace( ' ', '', $functions );
			$disabled = explode( ',', $functions );
		}

		return !( in_array( $pName, $disabled ));
	}

	public static function verify_hex_color( $pColor ) {
		$ret = null;

		if( preg_match('/^#[a-f0-9][6]$/i', $pColor) ) {
			$ret = $pColor;
		} elseif( preg_match('/^[a-f0-9][6]$/i', $pColor)) {
			//Check for a hex color string without hash 'c1c2b4'
			$ret = '#' . $pColor;
		} elseif( preg_match('/^#[a-f0-9][3]$/i', $pColor) ) {
			$ret = $pColor;
		} elseif( preg_match('/^[a-f0-9][3]$/i', $pColor)) {
			//Check for a hex color string without hash 'fff'
			$ret = '#' . $pColor;
		}
		return $ret;
	}

	/**
	 * html encode all characters
	 * taken from: http://www.bbsinc.com/iso8859.html
	 *
	 * @param string $pData string that might contain an email address
	 * @access public
	 * @return string encoded email address
	 * $note email regex taken from: http://www.regular-expressions.info/regexbuddy/email.html
	 */
	public static function encode_email_addresses( $pData ) {
		$trans = [
			// Upper case
			'A' => '&#065;',
			'B' => '&#066;',
			'C' => '&#067;',
			'D' => '&#068;',
			'E' => '&#069;',
			'F' => '&#070;',
			'G' => '&#071;',
			'H' => '&#072;',
			'I' => '&#073;',
			'J' => '&#074;',
			'K' => '&#075;',
			'L' => '&#076;',
			'M' => '&#077;',
			'N' => '&#078;',
			'O' => '&#079;',
			'P' => '&#080;',
			'Q' => '&#081;',
			'R' => '&#082;',
			'S' => '&#083;',
			'T' => '&#084;',
			'U' => '&#085;',
			'V' => '&#086;',
			'W' => '&#087;',
			'X' => '&#088;',
			'Y' => '&#089;',
			'Z' => '&#090;',

			// lower case
			'a' => '&#097;',
			'b' => '&#098;',
			'c' => '&#099;',
			'd' => '&#100;',
			'e' => '&#101;',
			'f' => '&#102;',
			'g' => '&#103;',
			'h' => '&#104;',
			'i' => '&#105;',
			'j' => '&#106;',
			'k' => '&#107;',
			'l' => '&#108;',
			'm' => '&#109;',
			'n' => '&#110;',
			'o' => '&#111;',
			'p' => '&#112;',
			'q' => '&#113;',
			'r' => '&#114;',
			's' => '&#115;',
			't' => '&#116;',
			'u' => '&#117;',
			'v' => '&#118;',
			'w' => '&#119;',
			'x' => '&#120;',
			'y' => '&#121;',
			'z' => '&#122;',

			// digits
			'0' => '&#048;',
			'1' => '&#049;',
			'2' => '&#050;',
			'3' => '&#051;',
			'4' => '&#052;',
			'5' => '&#053;',
			'6' => '&#054;',
			'7' => '&#055;',
			'8' => '&#056;',
			'9' => '&#057;',

			// special chars
			'_' => '&#095;',
			'-' => '&#045;',
			'.' => '&#046;',
			'@' => '&#064;',

			//'[' => '&#091;',
			//']' => '&#093;',
			//'|' => '&#124;',
			//'{' => '&#123;',
			//'}' => '&#125;',
			//'~' => '&#126;',
		];
		preg_match_all( "!\b".EMAIL_ADDRESS_REGEX."\b!", $pData, $addresses );
		foreach( $addresses[0] as $address ) {
			$encoded = strtr( $address, $trans );
			$pData = preg_replace( "/\b".preg_quote( $address )."\b/", $encoded, $pData );
		}

		return $pData;
	}

	/**
	 * validate email syntax
	 * php include as a string
	 *
	 * @param $pEmail the file to include
	 * @return string A string with the results of the file
	 **/
	public static function validate_email_syntax( $pEmail ) {
		return preg_match( "!^".EMAIL_ADDRESS_REGEX."$!", trim( $pEmail ));
	}

	/**
	 * get_include_contents -- handy function for getting the contents of a
	 * php include as a string
	 *
	 * @param $pFile the file to include
	 * @return string A string with the results of the file
	 **/
	public static function get_include_contents($pFile) {
		if( is_file( $pFile )) {
			ob_start();
			global $gContent, $gBitSystem, $gBitSmarty, $gLibertySystem, $gBitUser;
			include $pFile;
			$contents = ob_get_contents();
			ob_end_clean();
			return $contents;
		}
		return false;
	}

	/**
	 * Translate a string
	 *
	 * @param string $pString String that needs to be translated
	 * @access public
	 * @return string
	 */
	public static function tra( $pString ) {
		global $gBitLanguage;
		return $gBitLanguage->translate( $pString );
	}

	/**
	 * recursively remove files and directories
	 *
	 * @param string $pPath directory we want to remove
	 * @param boolean $pFollowLinks follow symlinks or not
	 * @access public
	 * @return bool true on success, false on failure
	 */
	public static function unlink_r( $pPath, $pFollowLinks = false ) {
		if( !empty( $pPath ) && is_dir( $pPath ) ) {
			if( $dir = opendir( $pPath ) ) {
				while( false !== ( $entry = readdir( $dir ) ) ) {
					if( is_file( "$pPath/$entry" ) || ( !$pFollowLinks && is_link( "$pPath/$entry" ) ) ) {
						@unlink( "$pPath/$entry" );
					} elseif( is_dir( "$pPath/$entry" ) && $entry != '.' && $entry != '..' ) {
						KernelTools::unlink_r( "$pPath/$entry" ) ;
					}
				}
				closedir( $dir ) ;
			}
			return @rmdir( $pPath );
		}
		return false;
	}

	/**
	 * recursively copy the contents of a directory to a new location akin to copy -r
	 *
	 * @param string $pSource source directory
	 * @param string $pTarget target directory
	 * @access public
	 * @return void
	 */
	public static function copy_r( $pSource, $pTarget ) {
		if( is_dir( $pSource )) {
			@KernelTools::mkdir_p( $pTarget );
			$d = dir( $pSource );

			while( false !== ( $entry = $d->read() )) {
				if( $entry == '.' || $entry == '..' ) {
					continue;
				}

				$source = $pSource.'/'.$entry;
				if( is_dir( $source )) {
					KernelTools::copy_r( $source, $pTarget.'/'.$entry );
					continue;
				}
				copy( $source, $pTarget.'/'.$entry );
			}

			$d->close();
		} else {
			copy( $pSource, $pTarget );
		}
	}

	/**
	 * Fetch the contents of a file on a remote host
	 *
	 * @param string $pUrl url to file to fetch
	 * @param boolean $pNoCurl skip the use of curl if this causes problems
	 * @access public
	 * @return false on failure, contents of file on success
	 */
	public static function bit_http_request( $pUrl, $pNoCurl = false ) {
		global $gBitSystem;
		$ret = false;

		if( !empty( $pUrl )) {
			$pUrl = trim( $pUrl );

			// rewrite url if sloppy # added a case for https urls
			if( !preg_match( "!^https?://!", $pUrl )) {
				$pUrl = "http://".$pUrl;
			}

			if( !preg_match("/^[-_a-zA-Z0-9:\/\.\?&;%=\+]*$/", $pUrl )) {
				return false;
			}

			// try using curl first as it allows the use of a proxy
			if( !$pNoCurl && function_exists( 'curl_init' )) {
				$curl = curl_init();
				curl_setopt( $curl, CURLOPT_URL, $pUrl );
				curl_setopt( $curl, CURLOPT_HEADER, 0 );
				curl_setopt( $curl, CURLOPT_USERAGENT, $_SERVER['HTTP_USER_AGENT'] );
				curl_setopt( $curl, CURLOPT_FOLLOWLOCATION, 1 );
				curl_setopt( $curl, CURLOPT_RETURNTRANSFER, 1 );
				curl_setopt( $curl, CURLOPT_TIMEOUT, 5 );

				// Proxy settings
				if( $gBitSystem->isFeatureActive( 'site_use_proxy' )) {
					curl_setopt( $curl, CURLOPT_PROXY, $gBitSystem->getConfig( 'site_proxy_host' ));
					curl_setopt( $curl, CURLOPT_PROXYPORT, $gBitSystem->getConfig( 'site_proxy_port' ));
					curl_setopt( $curl, CURLOPT_HTTPPROXYTUNNEL, 1);
				}

				$ret = curl_exec( $curl );
				curl_close( $curl );
			} else {
				// try using fsock now
				$parsed = parse_url( $pUrl );
				if( $fsock = @fsockopen( $parsed['host'], 80, $error['number'], $error['string'], 5 )) {
					@fwrite( $fsock, "GET ".$parsed['path'].( !empty( $parsed['query'] ) ? '?'.$parsed['query'] : '' )." HTTP/1.1\r\n" );
					@fwrite( $fsock, "HOST: {$parsed['host']}\r\n" );
					@fwrite( $fsock, "Connection: close\r\n\r\n" );

					$get_info = false;
					while( !@feof( $fsock )) {
						if( $get_info ) {
							$ret .= @fread( $fsock, 1024 );
						} else {
							if( @fgets( $fsock, 1024 ) == "\r\n" ) {
								$get_info = true;
							}
						}
					}
					@fclose( $fsock );
					if( !empty( $error['string'] )) {
						return false;
					}
				}
			}
		}

		return $ret;
	}

	/**
	 * Parse XML Attributes and return an array
	 *
	 * this function has a whopper of a RegEx.
	 * I nabbed it from http://www.phpbuilder.com/annotate/message.php3?id=1000234 - XOXO spiderr
	 *
	 * @param string $pString XML type string of parameters
	 * @access public
	 * @return array
	 */
	public static function parse_xml_attributes( string $pString ): array {
		//$parameters = [ '', '' ];
		$parameters = [];
		$regexp_str = "/([A-Za-z0-9_-]+)(?:\\s*=\\s*(?:(\"|\')((?:[\\\\].|[^\\\\]?)*?)(?:\\2)|([^=\\s]*)))?/";
		preg_match_all( $regexp_str, $pString, $matches, PREG_SET_ORDER );
		foreach( $matches as $key => $match ) {
			$attrib = $match[1];
			$value = $match[sizeof( $match )-1];      // The value can be at different indexes because of optional quotes, but we know it's always at the end.
			$value = preg_replace( "/\\\\(.)/","\\1",$value );
			$parameters[$attrib] = trim( $value, '\"' );
		}
		return $parameters;
	}

	/**
	 * XML Entity Mandatory Escape Characters
	 *
	 * @param string $string
	 * @param int $quote_style
	 * @access public
	 * @return string
	 */
	public static function xmlentities( string $string, int $quote_style=ENT_QUOTES ): string {
		static $trans;
		if( !isset( $trans )) {
			$trans = get_html_translation_table( HTML_ENTITIES, $quote_style );
			foreach( $trans as $key => $value ) {
				$trans[$key] = '&#'.ord( $key ).';';
			}

			// dont translate the '&' in case it is part of &xxx;
			$trans[chr(38)] = '&';
		}

		// after the initial translation, _do_ map standalone '&' into '&#38;'
		return preg_replace( "/&(?![A-Za-z]{0,4}\w{2,3};|#[0-9]{2,5};)/","&#38;" , strtr( $string, $trans ));
	}

	/**
	 * Redirect to another page or site
	 * @param string The url to redirect to
	 */
	public static function bit_redirect( $pUrl, $pStatusCode=HttpStatusCodes::HTTP_FOUND ) {
		// Handle non-3xx codes separately
		if( $pStatusCode && isset( $errors[$pStatusCode] ) ) {
			header( HttpStatusCodes::httpHeaderFor( $pStatusCode ) );
			$pStatusCode = null;
		}

		global $gBitUser;
		if( is_object( $gBitUser ) ) {
	//		apache_setenv( 'USERID', $gBitUser->getField('login', '-'), true );
		}

		if( empty($pUrl) ) {
			return;
		}

		// clean up URL before executing it
		while( strstr( $pUrl, '&&' ) ) {
			$pUrl = str_replace( '&&', '&', $pUrl );
		}

		while( strstr( $pUrl, '&amp;&amp;' ) ) {
			$pUrl = str_replace( '&amp;&amp;', '&amp;', $pUrl );
		}

		// header locates should not have the &amp; in the address it breaks things
		while( strstr( $pUrl, '&amp;' ) ) {
			$pUrl = str_replace( '&amp;', '&', $pUrl );
		}

		if( $pStatusCode ) {
			header( 'Location: ' . $pUrl, true, $pStatusCode );
		} else {
			header( 'Location: ' . $pUrl );
		}
		session_write_close();
		exit();
	}

	/**
	 * array_diff_keys
	 *
	 * @access public
	 */
	public static function array_diff_keys() {
		$args = func_get_args();

		$res = $args[0];
		if( !is_array( $res )) {
			return [];
		}

		for( $i = 1; $i < count( $args ); $i++ ) {
			if( !is_array( $args[$i] )) {
				continue;
			}
			foreach( $args[$i] as $key => $data ) {
				unset( $res[$key] );
			}
		}
		return $res;
	}

	/**
	 * trim_array
	 *
	 * @param array $pArray
	 * @access public
	 */
	public static function trim_array( &$pArray ) {
		if( is_array( $pArray ) ) {
			foreach( array_keys( $pArray ) as $key ) {
				if( is_string( $pArray[$key] ) ) {
					$pArray[$key] = trim( $pArray[$key] );
				}
			}
		}
	}

	/**
	 * ordinalize
	 *
	 * @param numeric $num Number to append th, st, nd, rd to - only makes sense when languages is english
	 * @access public
	 */
	public static function ordinalize( $num ) {
		$ord = '';
		if( is_numeric( $num ) ) {
			if( $num >= 11 and $num <= 19 ) {
				$ord = KernelTools::tra( "th" );
			} elseif( $num % 10 == 1 ) {
				$ord = KernelTools::tra( "st" );
			} elseif( $num % 10 == 2 ) {
				$ord = KernelTools::tra( "nd" );
			} elseif( $num % 10 == 3 ) {
				$ord = KernelTools::tra( "rd" );
			} else {
				$ord = KernelTools::tra( "th" );
			}
		}

		return $num.$ord;
	}

	/**
	 * Cleans file path according to system we're on
	 *
	 * @param string $pPath
	 * @access public
	 * @return string
	 */
	public static function clean_file_path( string $pPath ): string {
		$pPath = !empty($_SERVER["SERVER_SOFTWARE"]) && strpos($_SERVER["SERVER_SOFTWARE"],"IIS") ? str_replace( '\/', '\\', $pPath) : $pPath;
		return $pPath;
	}

	public static function httpScheme() {
		return 'http'.( ( isset($_SERVER['HTTPS'] ) && ( $_SERVER['HTTPS'] == 'on' ) ) ? 's' : '' );
	}

	public static function httpPrefix() {
		return KernelTools::httpScheme().'://'.$_SERVER['HTTP_HOST'];
	}

	/**
	* If an unrecoverable error has occurred, this method should be invoked. script exist occurs
	*
	* @param string $ pMsg error message to be displayed
	* @return void this function will DIE DIE DIE!!!
	* @access public
	*/
	public static function install_error( $pMsg = null ) {
		global $gBitDbType;
		// here we decide where to go. if there are no db settings yet, we go the welcome page.
			$step = isset( $gBitDbType ) ? 1 : 0;

		header( "Location: ".KernelTools::httpPrefix().BIT_ROOT_URL."install/install.php?step=".$step );
		die;
	}

	/**
	 * pear_check will check to see if a given PEAR module is installed
	 *
	 * @param string $pPearModule The name of the module in the format: Image/GraphViz.php
	 * @access public
	 * @return string with error message on failure, null on success
	 */
	public static function pear_check( $pPearModule = null ) {
		if( !@include_once "PEAR.php") {
			return KernelTools::tra( "PEAR is not installed." );
		} elseif( !empty( $pPearModule ) && !@include_once $pPearModule ) {
			$module = str_replace( ".php", "", str_replace( "/", "_", $pPearModule ));
			return KernelTools::tra( "The PEAR plugin <strong>$module</strong> is not installed. Install it with '<strong>pear install $module</strong>' or use your distribution's package manager.");
		}
			return null;

	}

	/**
	 * A set of compare functions that can be used in conjunction with usort() type functions
	 *
	 * @param array $ar1
	 * @param array $ar2
	 * @access public
	 * @return bool true on success, false on failure
	 */
	public static function usort_by_title( $ar1, $ar2 ) {
		if( !empty( $ar1['title'] ) && !empty( $ar2['title'] ) ) {
			return strcasecmp( $ar1['title'], $ar2['title'] );
		}
			return 0;

	}

	public static function compare_links( $ar1, $ar2 ) {
		return $ar1["links"] - $ar2["links"];
	}

	public static function compare_backlinks( $ar1, $ar2 ) {
		return $ar1["backlinks"] - $ar2["backlinks"];
	}

	public static function r_compare_links( $ar1, $ar2 ) {
		return $ar2["links"] - $ar1["links"];
	}

	public static function r_compare_backlinks( $ar1, $ar2 ) {
		return $ar2["backlinks"] - $ar1["backlinks"];
	}

	public static function compare_images( $ar1, $ar2 ) {
		return $ar1["images"] - $ar2["images"];
	}

	public static function r_compare_images( $ar1, $ar2 ) {
		return $ar2["images"] - $ar1["images"];
	}

	public static function compare_files( $ar1, $ar2 ) {
		return $ar1["files"] - $ar2["files"];
	}

	public static function r_compare_files( $ar1, $ar2 ) {
		return $ar2["files"] - $ar1["files"];
	}

	public static function compare_versions( $ar1, $ar2 ) {
		return $ar1["versions"] - $ar2["versions"];
	}

	public static function r_compare_versions( $ar1, $ar2 ) {
		return $ar2["versions"] - $ar1["versions"];
	}

	public static function compare_changed( $ar1, $ar2 ) {
		return $ar1["lastChanged"] - $ar2["lastChanged"];
	}

	public static function r_compare_changed( $ar1, $ar2 ) {
		return $ar2["lastChanged"] - $ar1["lastChanged"];
	}

	// ======================= deprecated functions =======================
	/**
	 * @deprecated deprecated since version 2.1.0-beta
	 */
	public static function chkgd2() {
		KernelTools::deprecated( 'Please use get_gd_version() instead' );
	}
}