gnu-social/plugins/DirectionDetector/DirectionDetectorPlugin.php

<?php

/**
 * DirectionDetector plugin, detects notices with RTL content & sets RTL
 * style for them.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.	If not, see <http://www.gnu.org/licenses/>.
 *
 * @category     Plugin
 * @package      StatusNet
 * @author		 Behrooz shabani (everplays) - <behrooz@rock.com>
 * @copyright    2009-2010 Behrooz shabani
 * @license      http://www.fsf.org/licensing/licenses/agpl-3.0.html AGPL 3.0
 *
 */

if (!defined('STATUSNET')) {
	exit(1);
}

define('DIRECTIONDETECTORPLUGIN_VERSION', '0.2.0');

class DirectionDetectorPlugin extends Plugin {
	/**
	 * SN plugin API, here we will make changes on rendered column
     *
     * @param object $notice notice is going to be saved
	 */
	public function onStartNoticeSave($notice){
		if(!preg_match('/<span class="rtl">/', $notice->rendered) && self::isRTL($notice->content))
			$notice->rendered = '<span class="rtl">'.$notice->rendered.'</span>';
		return true;
	}

	/**
	 * SN plugin API, here we will add css needed for modifiyed rendered
     *
     * @param Action $xml
	 */
	public function onEndShowStatusNetStyles($xml){
		$xml->element('style', array('type' => 'text/css'), 'span.rtl {display:block;direction:rtl;text-align:right;float:right;} .notice .author {float:left}');
	}
	
	/**
	 * is passed string a rtl content or not
     *
     * @param string $content
     * @return boolean
	 */
	public static function isRTL($content){
		$content = self::getClearText($content);
		$words = explode(' ', $content);
		$rtl = 0;
		foreach($words as $str)
			if(self::startsWithRTLCharacter($str))
				$rtl++;
			else
				$rtl--;
		if($rtl>0)// if number of rtl words is more than ltr words so it's a rtl content
			return true;
		elseif($rtl==0)
			// check first word again
			return self::startsWithRTLCharacter($words[0]);
		return false;		
	}
	
	/**
	 * checks that passed string starts with a RTL language or not
     *
     * @param string $str
     * @return boolean
	 */
	public static function startsWithRTLCharacter($str){
		if( is_array($cc = self::utf8ToUnicode(mb_substr($str, 0, 1, 'utf-8'))) )
			$cc = $cc[0];
		else
			return false;
		if($cc>=1536 && $cc<=1791) // arabic, persian, urdu, kurdish, ...
			return true;
		if($cc>=65136 && $cc<=65279) // arabic peresent 2
			return true;
		if($cc>=64336 && $cc<=65023) // arabic peresent 1
			return true;
		if($cc>=1424 && $cc<=1535) // hebrew
			return true;
		if($cc>=64256 && $cc<=64335) // hebrew peresent
			return true;
		if($cc>=1792 && $cc<=1871) // Syriac
			return true;
		if($cc>=1920 && $cc<=1983) // Thaana
			return true;
		if($cc>=1984 && $cc<=2047) // NKo
			return true;
		if($cc>=11568 && $cc<=11647) // Tifinagh
			return true;
		return false;
	}

	/**
	 * clears text from replys, tags, groups, reteets & whitespaces
     *
     * @param string $str
     * @return string
	 */
	private static function getClearText($str){
		$str = preg_replace('/@[^ ]+|![^ ]+|#[^ ]+/u', '', $str); // reply, tag, group
		$str = preg_replace('/^RT[: ]{1}| RT | RT: |^RD[: ]{1}| RD | RD: |[♺♻:]/u', '', $str); // redent, retweet
		$str = preg_replace("/[ \r\t\n]+/", ' ', trim($str)); // remove spaces
        return $str;
	}
	
	/**
	 * adds javascript to do same thing on input textarea
     *
     * @param Action $action
	 */
	function onEndShowScripts($action){
		if (common_logged_in()) {
			$action->script('plugins/DirectionDetector/jquery.DirectionDetector.js');
		}
	}

	/**
	 * Takes an UTF-8 string and returns an array of ints representing the 
	 * Unicode characters. Astral planes are supported ie. the ints in the
	 * output can be > 0xFFFF. O$ccurrances of the BOM are ignored. Surrogates
	 * are not allowed.
     *
     * @param string $str
     * @return mixed array of ints, or false on invalid input
	 */
	private static function utf8ToUnicode($str){
		$mState = 0;	   // cached expected number of octets after the current octet
				   // until the beginning of the next UTF8 character sequence
		$mUcs4	= 0;     // cached Unicode character
		$mBytes = 1;	   // cached expected number of octets in the current sequence
		$out = array();
		$len = strlen($str);

		for($i = 0; $i < $len; $i++) {
			$in = ord($str{$i});
			if (0 == $mState) {
				// When mState is zero we expect either a US-ASCII character or a
				// multi-octet sequence.
				if (0 == (0x80 & ($in))) {
				  	// US-ASCII, pass straight through.
			  		$out[] = $in;
			  		$mBytes = 1;
				} elseif (0xC0 == (0xE0 & ($in))) {
					// First octet of 2 octet sequence
					$mUcs4 = ($in);
					$mUcs4 = ($mUcs4 & 0x1F) << 6;
					$mState = 1;
					$mBytes = 2;
				} elseif (0xE0 == (0xF0 & ($in))) {
					// First octet of 3 octet sequence
					$mUcs4 = ($in);
					$mUcs4 = ($mUcs4 & 0x0F) << 12;
					$mState = 2;
					$mBytes = 3;
				} elseif (0xF0 == (0xF8 & ($in))) {
					// First octet of 4 octet sequence
					$mUcs4 = ($in);
					$mUcs4 = ($mUcs4 & 0x07) << 18;
					$mState = 3;
					$mBytes = 4;
				} elseif (0xF8 == (0xFC & ($in))) {
					/* First octet of 5 octet sequence.
					 *
					 * This is illegal because the encoded codepoint must be either
					 * (a) not the shortest form or
					 * (b) outside the Unicode range of 0-0x10FFFF.
					 * Rather than trying to resynchronize, we will carry on until the end
					 * of the sequence and let the later error handling code catch it.
					 */
					$mUcs4 = ($in);
					$mUcs4 = ($mUcs4 & 0x03) << 24;
					$mState = 4;
					$mBytes = 5;
				} elseif (0xFC == (0xFE & ($in))) {
					// First octet of 6 octet sequence, see comments for 5 octet sequence.
					$mUcs4 = ($in);
					$mUcs4 = ($mUcs4 & 1) << 30;
					$mState = 5;
					$mBytes = 6;
				} else {
					/* Current octet is neither in the US-ASCII range nor a legal first
					 * octet of a multi-octet sequence.
					 */
					return false;
				}
			} else {
				// When mState is non-zero, we expect a continuation of the multi-octet
				// sequence
				if (0x80 == (0xC0 & ($in))) {
					// Legal continuation.
					$shift = ($mState - 1) * 6;
					$tmp = $in;
					$tmp = ($tmp & 0x0000003F) << $shift;
					$mUcs4 |= $tmp;
					if (0 == --$mState) {
						/* End of the multi-octet sequence. mUcs4 now contains the final
						 * Unicode codepoint to be output
						 *
						 * Check for illegal sequences and codepoints.
						 */
						// From Unicode 3.1, non-shortest form is illegal
						if	(
								((2 == $mBytes) && ($mUcs4 < 0x0080)) ||
								((3 == $mBytes) && ($mUcs4 < 0x0800)) ||
								((4 == $mBytes) && ($mUcs4 < 0x10000)) ||
								(4 < $mBytes) ||
								// From Unicode 3.2, surrogate characters are illegal
								(($mUcs4 & 0xFFFFF800) == 0xD800) ||
								// Codepoints outside the Unicode range are illegal
								($mUcs4 > 0x10FFFF)
							){
							return false;
						}
						if (0xFEFF != $mUcs4) {
							$out[] = $mUcs4;
						}
						//initialize UTF8 cache
						$mState = 0;
						$mUcs4  = 0;
						$mBytes = 1;
					}
				} else {
					/* ((0xC0 & (*in) != 0x80) && (mState != 0))
					 * 
					 * Incomplete multi-octet sequence.
					 */
					return false;
				}
			}
		}
		return $out;
	}

	/**
	 * plugin details
	 */
	function onPluginVersion(&$versions){
		$versions[] = array(
			'name' => 'Direction detector',
			'version' => DIRECTIONDETECTORPLUGIN_VERSION,
			'author' => 'Behrooz Shabani',
			'rawdescription' => _m('Shows notices with right-to-left content in correct direction.')
		);
		return true;
	}
}

/*
// Example:
var_dump(DirectionDetectorPlugin::isRTL('RT @everplays ♺: دادگاه به دليل عدم حضور وکلای متهمان بنا بر اصل ١٣٥ قانون اساسی غير قانونی است')); // true
*/