wp-includes/gettext.php

   1 <?php
   2 /*
   3          Copyright (c) 2003 Danilo Segan <danilo@kvota.net>.
   4          Copyright (c) 2005 Nico Kaiser <nico@siriux.net>
   5
   6          This file is part of PHP-gettext.
   7
   8          PHP-gettext is free software; you can redistribute it and/or modify
   9          it under the terms of the GNU General Public License as published by
  10          the Free Software Foundation; either version 2 of the License, or
  11          (at your option) any later version.
  12
  13          PHP-gettext is distributed in the hope that it will be useful,
  14          but WITHOUT ANY WARRANTY; without even the implied warranty of
  15          MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16          GNU General Public License for more details.
  17
  18          You should have received a copy of the GNU General Public License
  19          along with PHP-gettext; if not, write to the Free Software
  20          Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21
  22 */
  23
  24 /**
  25  * Provides a simple gettext replacement that works independently from
  26  * the system's gettext abilities.
  27  * It can read MO files and use them for translating strings.
  28  * The files are passed to gettext_reader as a Stream (see streams.php)
  29  *
  30  * This version has the ability to cache all strings and translations to
  31  * speed up the string lookup.
  32  * While the cache is enabled by default, it can be switched off with the
  33  * second parameter in the constructor (e.g. whenusing very large MO files
  34  * that you don't want to keep in memory)
  35  */
  36 class gettext_reader {
  37         //public:
  38          var $error = 0; // public variable that holds error code (0 if no error)
  39
  40          //private:
  41         var $BYTEORDER = 0;        // 0: low endian, 1: big endian
  42         var $STREAM = NULL;
  43         var $short_circuit = false;
  44         var $enable_cache = false;
  45         var $originals = NULL;      // offset of original table
  46         var $translations = NULL;    // offset of translation table
  47         var $pluralheader = NULL;    // cache header field for plural forms
  48         var $select_string_function = NULL; // cache function, which chooses plural forms
  49         var $total = 0;          // total string count
  50         var $table_originals = NULL;  // table for original strings (offsets)
  51         var $table_translations = NULL;  // table for translated strings (offsets)
  52         var $cache_translations = NULL;  // original -> translation mapping
  53
  54
  55         /* Methods */
  56
  57
  58         /**
  59          * Reads a 32bit Integer from the Stream
  60          *
  61          * @access private
  62          * @return Integer from the Stream
  63          */
  64         function readint() {
  65                 if ($this->BYTEORDER == 0) {
  66                         // low endian
  67                         $low_end = unpack('V', $this->STREAM->read(4));
  68                         return array_shift($low_end);
  69                 } else {
  70                         // big endian
  71                         $big_end = unpack('N', $this->STREAM->read(4));
  72                         return array_shift($big_end);
  73                 }
  74         }
  75
  76         /**
  77          * Reads an array of Integers from the Stream
  78          *
  79          * @param int count How many elements should be read
  80          * @return Array of Integers
  81          */
  82         function readintarray($count) {
  83         if ($this->BYTEORDER == 0) {
  84                         // low endian
  85                         return unpack('V'.$count, $this->STREAM->read(4 * $count));
  86                 } else {
  87                         // big endian
  88                         return unpack('N'.$count, $this->STREAM->read(4 * $count));
  89                 }
  90         }
  91
  92         /**
  93          * Constructor
  94          *
  95          * @param object Reader the StreamReader object
  96          * @param boolean enable_cache Enable or disable caching of strings (default on)
  97          */
  98         function gettext_reader($Reader, $enable_cache = true) {
  99                 // If there isn't a StreamReader, turn on short circuit mode.
 100                 if (! $Reader || isset($Reader->error) ) {
 101                         $this->short_circuit = true;
 102                         return;
 103                 }
 104
 105                 // Caching can be turned off
 106                 $this->enable_cache = $enable_cache;
 107
 108                 // $MAGIC1 = (int)0x950412de; //bug in PHP 5.0.2, see https://savannah.nongnu.org/bugs/?func=detailitem&item_id=10565
 109                 $MAGIC1 = (int) - 1794895138;
 110                 // $MAGIC2 = (int)0xde120495; //bug
 111                 $MAGIC2 = (int) - 569244523;
 112                 // 64-bit fix
 113                 $MAGIC3 = (int) 2500072158;
 114
 115                 $this->STREAM = $Reader;
 116                 $magic = $this->readint();
 117                 if ($magic == ($MAGIC1 & 0xFFFFFFFF) || $magic == ($MAGIC3 & 0xFFFFFFFF)) { // to make sure it works for 64-bit platforms
 118                         $this->BYTEORDER = 0;
 119                 } elseif ($magic == ($MAGIC2 & 0xFFFFFFFF)) {
 120                         $this->BYTEORDER = 1;
 121                 } else {
 122                         $this->error = 1; // not MO file
 123                         return false;
 124                 }
 125
 126                 // FIXME: Do we care about revision? We should.
 127                 $revision = $this->readint();
 128
 129                 $this->total = $this->readint();
 130                 $this->originals = $this->readint();
 131                 $this->translations = $this->readint();
 132         }
 133
 134         /**
 135          * Loads the translation tables from the MO file into the cache
 136          * If caching is enabled, also loads all strings into a cache
 137          * to speed up translation lookups
 138          *
 139          * @access private
 140          */
 141         function load_tables() {
 142                 if (is_array($this->cache_translations) &&
 143                         is_array($this->table_originals) &&
 144                         is_array($this->table_translations))
 145                         return;
 146
 147                 /* get original and translations tables */
 148                 $this->STREAM->seekto($this->originals);
 149                 $this->table_originals = $this->readintarray($this->total * 2);
 150                 $this->STREAM->seekto($this->translations);
 151                 $this->table_translations = $this->readintarray($this->total * 2);
 152
 153                 if ($this->enable_cache) {
 154                         $this->cache_translations = array ();
 155                         /* read all strings in the cache */
 156                         for ($i = 0; $i < $this->total; $i++) {
 157                                 $this->STREAM->seekto($this->table_originals[$i * 2 + 2]);
 158                                 $original = $this->STREAM->read($this->table_originals[$i * 2 + 1]);
 159                                 $this->STREAM->seekto($this->table_translations[$i * 2 + 2]);
 160                                 $translation = $this->STREAM->read($this->table_translations[$i * 2 + 1]);
 161                                 $this->cache_translations[$original] = $translation;
 162                         }
 163                 }
 164         }
 165
 166         /**
 167          * Returns a string from the "originals" table
 168          *
 169          * @access private
 170          * @param int num Offset number of original string
 171          * @return string Requested string if found, otherwise ''
 172          */
 173         function get_original_string($num) {
 174                 $length = $this->table_originals[$num * 2 + 1];
 175                 $offset = $this->table_originals[$num * 2 + 2];
 176                 if (! $length)
 177                         return '';
 178                 $this->STREAM->seekto($offset);
 179                 $data = $this->STREAM->read($length);
 180                 return (string)$data;
 181         }
 182
 183         /**
 184          * Returns a string from the "translations" table
 185          *
 186          * @access private
 187          * @param int num Offset number of original string
 188          * @return string Requested string if found, otherwise ''
 189          */
 190         function get_translation_string($num) {
 191                 $length = $this->table_translations[$num * 2 + 1];
 192                 $offset = $this->table_translations[$num * 2 + 2];
 193                 if (! $length)
 194                         return '';
 195                 $this->STREAM->seekto($offset);
 196                 $data = $this->STREAM->read($length);
 197                 return (string)$data;
 198         }
 199
 200         /**
 201          * Binary search for string
 202          *
 203          * @access private
 204          * @param string string
 205          * @param int start (internally used in recursive function)
 206          * @param int end (internally used in recursive function)
 207          * @return int string number (offset in originals table)
 208          */
 209         function find_string($string, $start = -1, $end = -1) {
 210                 if (($start == -1) or ($end == -1)) {
 211                         // find_string is called with only one parameter, set start end end
 212                         $start = 0;
 213                         $end = $this->total;
 214                 }
 215                 if (abs($start - $end) <= 1) {
 216                         // We're done, now we either found the string, or it doesn't exist
 217                         $txt = $this->get_original_string($start);
 218                         if ($string == $txt)
 219                                 return $start;
 220                         else
 221                                 return -1;
 222                 } else if ($start > $end) {
 223                         // start > end -> turn around and start over
 224                         return $this->find_string($string, $end, $start);
 225                 } else {
 226                         // Divide table in two parts
 227                         $half = (int)(($start + $end) / 2);
 228                         $cmp = strcmp($string, $this->get_original_string($half));
 229                         if ($cmp == 0)
 230                                 // string is exactly in the middle => return it
 231                                 return $half;
 232                         else if ($cmp < 0)
 233                                 // The string is in the upper half
 234                                 return $this->find_string($string, $start, $half);
 235                         else
 236                                 // The string is in the lower half
 237                                 return $this->find_string($string, $half, $end);
 238                 }
 239         }
 240
 241         /**
 242          * Translates a string
 243          *
 244          * @access public
 245          * @param string string to be translated
 246          * @return string translated string (or original, if not found)
 247          */
 248         function translate($string) {
 249                 if ($this->short_circuit)
 250                         return $string;
 251                 $this->load_tables();
 252
 253                 if ($this->enable_cache) {
 254                         // Caching enabled, get translated string from cache
 255                         if (array_key_exists($string, $this->cache_translations))
 256                                 return $this->cache_translations[$string];
 257                         else
 258                                 return $string;
 259                 } else {
 260                         // Caching not enabled, try to find string
 261                         $num = $this->find_string($string);
 262                         if ($num == -1)
 263                                 return $string;
 264                         else
 265                                 return $this->get_translation_string($num);
 266                 }
 267         }
 268
 269         /**
 270          * Get possible plural forms from MO header
 271          *
 272          * @access private
 273          * @return string plural form header
 274          */
 275         function get_plural_forms() {
 276                 // lets assume message number 0 is header
 277                 // this is true, right?
 278                 $this->load_tables();
 279
 280                 // cache header field for plural forms
 281                 if (! is_string($this->pluralheader)) {
 282                         if ($this->enable_cache) {
 283                                 $header = $this->cache_translations[""];
 284                         } else {
 285                                 $header = $this->get_translation_string(0);
 286                         }
 287                         $header .= "\n"; //make sure our regex matches
 288                         if (eregi("plural-forms: ([^\n]*)\n", $header, $regs))
 289                                 $expr = $regs[1];
 290                         else
 291                                 $expr = "nplurals=2; plural=n == 1 ? 0 : 1;";
 292
 293                         // add parentheses
 294                         // important since PHP's ternary evaluates from left to right
 295                         $expr.= ';';
 296                         $res= '';
 297                         $p= 0;
 298                         for ($i= 0; $i < strlen($expr); $i++) {
 299                                 $ch= $expr[$i];
 300                                 switch ($ch) {
 301                                         case '?':
 302                                                 $res.= ' ? (';
 303                                                 $p++;
 304                                                 break;
 305                                         case ':':
 306                                                 $res.= ') : (';
 307                                                 break;
 308                                         case ';':
 309                                                 $res.= str_repeat( ')', $p) . ';';
 310                                                 $p= 0;
 311                                                 break;
 312                                         default:
 313                                                 $res.= $ch;
 314                                 }
 315                         }
 316                         $this->pluralheader = $res;
 317                 }
 318
 319                 return $this->pluralheader;
 320         }
 321
 322         /**
 323          * Detects which plural form to take
 324          *
 325          * @access private
 326          * @param n count
 327          * @return int array index of the right plural form
 328          */
 329         function select_string($n) {
 330                 if (is_null($this->select_string_function)) {
 331                         $string = $this->get_plural_forms();
 332                         if (preg_match("/nplurals\s*=\s*(\d+)\s*\;\s*plural\s*=\s*(.*?)\;+/", $string, $matches)) {
 333                                 $nplurals = $matches[1];
 334                                 $expression = $matches[2];
 335                                 $expression = str_replace("n", '$n', $expression);
 336                         } else {
 337                                 $nplurals = 2;
 338                                 $expression = ' $n == 1 ? 0 : 1 ';
 339                         }
 340                         $func_body = "
 341                                 \$plural = ($expression);
 342                                 return (\$plural <= $nplurals)? \$plural : \$plural - 1;";
 343                         $this->select_string_function = create_function('$n', $func_body);
 344                 }
 345                 return call_user_func($this->select_string_function, $n);
 346         }
 347
 348         /**
 349          * Plural version of gettext
 350          *
 351          * @access public
 352          * @param string single
 353          * @param string plural
 354          * @param string number
 355          * @return translated plural form
 356          */
 357         function ngettext($single, $plural, $number) {
 358                 if ($this->short_circuit) {
 359                         if ($number != 1)
 360                                 return $plural;
 361                         else
 362                                 return $single;
 363                 }
 364
 365                 // find out the appropriate form
 366                 $select = $this->select_string($number);
 367
 368                 // this should contains all strings separated by NULLs
 369                 $key = $single.chr(0).$plural;
 370
 371
 372                 if ($this->enable_cache) {
 373                         if (! array_key_exists($key, $this->cache_translations)) {
 374                                 return ($number != 1) ? $plural : $single;
 375                         } else {
 376                                 $result = $this->cache_translations[$key];
 377                                 $list = explode(chr(0), $result);
 378                                 return $list[$select];
 379                         }
 380                 } else {
 381                         $num = $this->find_string($key);
 382                         if ($num == -1) {
 383                                 return ($number != 1) ? $plural : $single;
 384                         } else {
 385                                 $result = $this->get_translation_string($num);
 386                                 $list = explode(chr(0), $result);
 387                                 return $list[$select];
 388                         }
 389                 }
 390         }
 391
 392 }
 393
 394 ?>