<?php

/**

 * PHP-Gettext External Library: gettext_reader class

 *

 * @package External

 * @subpackage PHP-gettext

 *

 * @internal

	 Copyright (c) 2003 Danilo Segan <danilo@kvota.net>.

	 Copyright (c) 2005 Nico Kaiser <nico@siriux.net>

	 This file is part of PHP-gettext.

	 PHP-gettext 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 2 of the License, or

	 (at your option) any later version.

	 PHP-gettext 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 PHP-gettext; if not, write to the Free Software

	 Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

*/

/**

 * Provides a simple gettext replacement that works independently from

 * the system's gettext abilities.

 * It can read MO files and use them for translating strings.

 * The files are passed to gettext_reader as a Stream (see streams.php)

 *

 * This version has the ability to cache all strings and translations to

 * speed up the string lookup.

 * While the cache is enabled by default, it can be switched off with the

 * second parameter in the constructor (e.g. whenusing very large MO files

 * that you don't want to keep in memory)

 */

class gettext_reader {

	//public:

	 var $error = 0; // public variable that holds error code (0 if no error)

	 //private:

	var $BYTEORDER = 0;        // 0: low endian, 1: big endian

	var $STREAM = NULL;

	var $short_circuit = false;

	var $enable_cache = false;

	var $originals = NULL;      // offset of original table

	var $translations = NULL;    // offset of translation table

	var $pluralheader = NULL;    // cache header field for plural forms

	var $select_string_function = NULL; // cache function, which chooses plural forms

	var $total = 0;          // total string count

	var $table_originals = NULL;  // table for original strings (offsets)

	var $table_translations = NULL;  // table for translated strings (offsets)

	var $cache_translations = NULL;  // original -> translation mapping

	/* Methods */

	/**

	 * Reads a 32bit Integer from the Stream

	 *

	 * @access private

	 * @return Integer from the Stream

	 */

	function readint() {

		if ($this->BYTEORDER == 0) {

			// low endian

			$low_end = unpack('V', $this->STREAM->read(4));

			return array_shift($low_end);

		} else {

			// big endian

			$big_end = unpack('N', $this->STREAM->read(4));

			return array_shift($big_end);

		}

	}

	/**

	 * Reads an array of Integers from the Stream

	 *

	 * @param int count How many elements should be read

	 * @return Array of Integers

	 */

	function readintarray($count) {

	if ($this->BYTEORDER == 0) {

			// low endian

			return unpack('V'.$count, $this->STREAM->read(4 * $count));

		} else {

			// big endian

			return unpack('N'.$count, $this->STREAM->read(4 * $count));

		}

	}

	/**

	 * Constructor

	 *

	 * @param object Reader the StreamReader object

	 * @param boolean enable_cache Enable or disable caching of strings (default on)

	 */

	function gettext_reader($Reader, $enable_cache = true) {

		// If there isn't a StreamReader, turn on short circuit mode.

		if (! $Reader || isset($Reader->error) ) {

			$this->short_circuit = true;

			return;

		}

		// Caching can be turned off

		$this->enable_cache = $enable_cache;

		// $MAGIC1 = (int)0x950412de; //bug in PHP 5.0.2, see https://savannah.nongnu.org/bugs/?func=detailitem&item_id=10565

		$MAGIC1 = (int) - 1794895138;

		// $MAGIC2 = (int)0xde120495; //bug

		$MAGIC2 = (int) - 569244523;

		// 64-bit fix

		$MAGIC3 = (int) 2500072158;

		$this->STREAM = $Reader;

		$magic = $this->readint();

		if ($magic == $MAGIC1 || $magic == $MAGIC3) { // to make sure it works for 64-bit platforms

			$this->BYTEORDER = 0;

		} elseif ($magic == ($MAGIC2 & 0xFFFFFFFF)) {

			$this->BYTEORDER = 1;

		} else {

			$this->error = 1; // not MO file

			return false;

		}

		// FIXME: Do we care about revision? We should.

		$revision = $this->readint();

		$this->total = $this->readint();

		$this->originals = $this->readint();

		$this->translations = $this->readint();

	}

	/**

	 * Loads the translation tables from the MO file into the cache

	 * If caching is enabled, also loads all strings into a cache

	 * to speed up translation lookups

	 *

	 * @access private

	 */

	function load_tables() {

		if (is_array($this->cache_translations) &&

			is_array($this->table_originals) &&

			is_array($this->table_translations))

			return;

		/* get original and translations tables */

		$this->STREAM->seekto($this->originals);

		$this->table_originals = $this->readintarray($this->total * 2);

		$this->STREAM->seekto($this->translations);

		$this->table_translations = $this->readintarray($this->total * 2);

		if ($this->enable_cache) {

			$this->cache_translations = array ();

			/* read all strings in the cache */

			for ($i = 0; $i < $this->total; $i++) {

				$this->STREAM->seekto($this->table_originals[$i * 2 + 2]);

				$original = $this->STREAM->read($this->table_originals[$i * 2 + 1]);

				$this->STREAM->seekto($this->table_translations[$i * 2 + 2]);

				$translation = $this->STREAM->read($this->table_translations[$i * 2 + 1]);

				$this->cache_translations[$original] = $translation;

			}

		}

	}

	/**

	 * Returns a string from the "originals" table

	 *

	 * @access private

	 * @param int num Offset number of original string

	 * @return string Requested string if found, otherwise ''

	 */

	function get_original_string($num) {

		$length = $this->table_originals[$num * 2 + 1];

		$offset = $this->table_originals[$num * 2 + 2];

		if (! $length)

			return '';

		$this->STREAM->seekto($offset);

		$data = $this->STREAM->read($length);

		return (string)$data;

	}

	/**

	 * Returns a string from the "translations" table

	 *

	 * @access private

	 * @param int num Offset number of original string

	 * @return string Requested string if found, otherwise ''

	 */

	function get_translation_string($num) {

		$length = $this->table_translations[$num * 2 + 1];

		$offset = $this->table_translations[$num * 2 + 2];

		if (! $length)

			return '';

		$this->STREAM->seekto($offset);

		$data = $this->STREAM->read($length);

		return (string)$data;

	}

	/**

	 * Binary search for string

	 *

	 * @access private

	 * @param string string

	 * @param int start (internally used in recursive function)

	 * @param int end (internally used in recursive function)

	 * @return int string number (offset in originals table)

	 */

	function find_string($string, $start = -1, $end = -1) {

		if (($start == -1) or ($end == -1)) {

			// find_string is called with only one parameter, set start end end

			$start = 0;

			$end = $this->total;

		}

		if (abs($start - $end) <= 1) {

			// We're done, now we either found the string, or it doesn't exist

			$txt = $this->get_original_string($start);

			if ($string == $txt)

				return $start;

			else

				return -1;

		} else if ($start > $end) {

			// start > end -> turn around and start over

			return $this->find_string($string, $end, $start);

		} else {

			// Divide table in two parts

			$half = (int)(($start + $end) / 2);

			$cmp = strcmp($string, $this->get_original_string($half));

			if ($cmp == 0)

				// string is exactly in the middle => return it

				return $half;

			else if ($cmp < 0)

				// The string is in the upper half

				return $this->find_string($string, $start, $half);

			else

				// The string is in the lower half

				return $this->find_string($string, $half, $end);

		}

	}

	/**

	 * Translates a string

	 *

	 * @access public

	 * @param string string to be translated

	 * @return string translated string (or original, if not found)

	 */

	function translate($string) {

		if ($this->short_circuit)

			return $string;

		$this->load_tables();

		if ($this->enable_cache) {

			// Caching enabled, get translated string from cache

			if (array_key_exists($string, $this->cache_translations))

				return $this->cache_translations[$string];

			else

				return $string;

		} else {

			// Caching not enabled, try to find string

			$num = $this->find_string($string);

			if ($num == -1)

				return $string;

			else

				return $this->get_translation_string($num);

		}

	}

	/**

	 * Get possible plural forms from MO header

	 *

	 * @access private

	 * @return string plural form header

	 */

	function get_plural_forms() {

		// lets assume message number 0 is header

		// this is true, right?

		$this->load_tables();

		// cache header field for plural forms

		if (! is_string($this->pluralheader)) {

			if ($this->enable_cache) {

				$header = $this->cache_translations[""];

			} else {

				$header = $this->get_translation_string(0);

			}

			$header .= "\n"; //make sure our regex matches

			if (eregi("plural-forms: ([^\n]*)\n", $header, $regs))

				$expr = $regs[1];

			else

				$expr = "nplurals=2; plural=n == 1 ? 0 : 1;";

			// add parentheses

 			// important since PHP's ternary evaluates from left to right

 			$expr.= ';';

 			$res= '';

 			$p= 0;

 			for ($i= 0; $i < strlen($expr); $i++) {

				$ch= $expr[$i];

				switch ($ch) {

					case '?':

						$res.= ' ? (';

						$p++;

						break;

					case ':':

						$res.= ') : (';

						break;

					case ';':

						$res.= str_repeat( ')', $p) . ';';

						$p= 0;

						break;

					default:

						$res.= $ch;

				}

			}

			$this->pluralheader = $res;

		}

		return $this->pluralheader;

	}

	/**

	 * Detects which plural form to take

	 *

	 * @access private

	 * @param n count

	 * @return int array index of the right plural form

	 */

	function select_string($n) {

		if (is_null($this->select_string_function)) {

			$string = $this->get_plural_forms();

			if (preg_match("/nplurals\s*=\s*(\d+)\s*\;\s*plural\s*=\s*(.*?)\;+/", $string, $matches)) {

				$nplurals = $matches[1];

				$expression = $matches[2];

				$expression = str_replace("n", '$n', $expression);

			} else {

				$nplurals = 2;

				$expression = ' $n == 1 ? 0 : 1 ';

			}

			$func_body = "

				\$plural = ($expression);

				return (\$plural <= $nplurals)? \$plural : \$plural - 1;";

			$this->select_string_function = create_function('$n', $func_body);

		}

		return call_user_func($this->select_string_function, $n);

	}

	/**

	 * Plural version of gettext

	 *

	 * @access public

	 * @param string single

	 * @param string plural

	 * @param string number

	 * @return translated plural form

	 */

	function ngettext($single, $plural, $number) {

		if ($this->short_circuit) {

			if ($number != 1)

				return $plural;

			else

				return $single;

		}

		// find out the appropriate form

		$select = $this->select_string($number);

		// this should contains all strings separated by NULLs

		$key = $single.chr(0).$plural;

		if ($this->enable_cache) {

			if (! array_key_exists($key, $this->cache_translations)) {

				return ($number != 1) ? $plural : $single;

			} else {

				$result = $this->cache_translations[$key];

				$list = explode(chr(0), $result);

				return $list[$select];

			}

		} else {

			$num = $this->find_string($key);

			if ($num == -1) {

				return ($number != 1) ? $plural : $single;

			} else {

				$result = $this->get_translation_string($num);

				$list = explode(chr(0), $result);

				return $list[$select];

			}

		}

	}

}

?>