<?php
/*
Copyright (c) 2003, 2009 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:
public $error = 0; // public variable that holds error code (0 if no error)
//private:
public $BYTEORDER = 0; // 0: low endian, 1: big endian
public $STREAM = null;
public $short_circuit = false;
public $enable_cache = false;
public $originals = null; // offset of original table
public $translations = null; // offset of translation table
public $pluralheader = null; // cache header field for plural forms
public $total = 0; // total string count
public $table_originals = null; // table for original strings (offsets)
public $table_translations = null; // table for translated strings (offsets)
public $cache_translations = null; // original -> translation mapping
/* Methods */
/**
* Reads a 32bit Integer from the Stream
*
* @access private
* @return Integer from the Stream
*/
public function readint()
{
if ($this->BYTEORDER == 0) {
// low endian
$input=unpack('V', $this->STREAM->read(4));
return array_shift($input);
} else {
// big endian
$input=unpack('N', $this->STREAM->read(4));
return array_shift($input);
}
}
public function read($bytes)
{
return $this->STREAM->read($bytes);
}
/**
* Reads an array of Integers from the Stream
*
* @param int count How many elements should be read
* @return Array of Integers
*/
public 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 * $count));
}
}
/**
* Constructor
*
* @param object Reader the StreamReader object
* @param boolean enable_cache Enable or disable caching of strings (default on)
*/
public function gettext_reader($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 = "\x95\x04\x12\xde";
$MAGIC2 = "\xde\x12\x04\x95";
$this->STREAM = $Reader;
$magic = $this->read(4);
if ($magic == $MAGIC1) {
$this->BYTEORDER = 1;
} elseif ($magic == $MAGIC2) {
$this->BYTEORDER = 0;
} 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 = $this->readint();
}
/**
* Loads the translation tables from the MO file into the cache
* If caching is enabled, also loads all strings into a cache
* to speed up translation lookups
*
* @access private
*/
public function load_tables()
{
if (is_array($this->cache_translations) &&
is_array($this->table_originals) &&
is_array($this->table_translations)) {
return;
}
/* get original and translations tables */
if (!is_array($this->table_originals)) {
$this->STREAM->seekto($this->originals);
$this->table_originals = $this->readintarray($this->total * 2);
}
if (!is_array($this->table_translations)) {
$this->STREAM->seekto($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] = $translation;
}
}
}
/**
* Returns a string from the "originals" table
*
* @access private
* @param int num Offset number of original string
* @return string Requested string if found, otherwise ''
*/
public function get_original_string($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)$data;
}
/**
* Returns a string from the "translations" table
*
* @access private
* @param int num Offset number of original string
* @return string Requested string if found, otherwise ''
*/
public function get_translation_string($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)$data;
}
/**
* Binary search for string
*
* @access private
* @param string string
* @param int start (internally used in recursive function)
* @param int end (internally used in recursive function)
* @return int string number (offset in originals table)
*/
public function find_string($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 $start;
} else {
return -1;
}
} elseif ($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 $half;
} elseif ($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, $end);
}
}
}
/**
* Translates a string
*
* @access public
* @param string string to be translated
* @return string translated string (or original, if not found)
*/
public function translate($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);
}
}
}
/**
* Sanitize plural form expression for use in PHP eval call.
*
* @access private
* @return string sanitized plural form expression
*/
public function sanitize_plural_expression($expr)
{
// Get rid of disallowed characters.
$expr = preg_replace('@[^a-zA-Z0-9_:;\(\)\?\|\&=!<>+*/\%-]@', '', $expr);
// Add parenthesis for tertiary '?' operator.
$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;
}
}
return $res;
}
/**
* Parse full PO header and extract only plural forms line.
*
* @access private
* @return string verbatim plural form header field
*/
public function extract_plural_forms_header_from_po_header($header)
{
if (preg_match("/(^|\n)plural-forms: ([^\n]*)\n/i", $header, $regs)) {
$expr = $regs[2];
} else {
$expr = "nplurals=2; plural=n == 1 ? 0 : 1;";
}
return $expr;
}
/**
* Get possible plural forms from MO header
*
* @access private
* @return string plural form header
*/
public 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);
}
$expr = $this->extract_plural_forms_header_from_po_header($header);
$this->pluralheader = $this->sanitize_plural_expression($expr);
}
return $this->pluralheader;
}
/**
* Detects which plural form to take
*
* @access private
* @param n count
* @return int array index of the right plural form
*/
public function select_string($n)
{
if (!is_int($n)) {
throw new InvalidArgumentException(
"Select_string only accepts integers: " . $n
);
}
$string = $this->get_plural_forms();
$string = str_replace('nplurals', "\$total", $string);
$string = str_replace("n", $n, $string);
$string = str_replace('plural', "\$plural", $string);
$total = 0;
$plural = 0;
eval("$string");
if ($plural >= $total) {
$plural = $total - 1;
}
return $plural;
}
/**
* Plural version of gettext
*
* @access public
* @param string single
* @param string plural
* @param string number
* @return translated plural form
*/
public function ngettext($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];
}
}
}
public function pgettext($context, $msgid)
{
$key = $context . chr(4) . $msgid;
$ret = $this->translate($key);
if (strpos($ret, "\004") !== false) {
return $msgid;
} else {
return $ret;
}
}
public function npgettext($context, $singular, $plural, $number)
{
$key = $context . chr(4) . $singular;
$ret = $this->ngettext($key, $plural, $number);
if (strpos($ret, "\004") !== false) {
return $singular;
} else {
return $ret;
}
}
}