Feature 1451 : localization with gettext

Use php-gettext (developpement version rev43, because of php5.3) as fallback
Use native language (english) instead of key for translation
Keep directory en_UK for english customization
Need some refactoring for plurals

Todo : managing plugins in the same way

git-svn-id: http://piwigo.org/svn/trunk@5021 68402e56-0260-453c-a942-63ccdbb3a9ee

1 files changed, 408 insertions, 0 deletions

diff --git a/include/php-gettext/gettext.php b/include/php-gettext/gettext.php
new file mode 100644
index 000000000..f11da2e27
--- /dev/null
+++ b/include/php-gettext/gettext.php
@@ -0,0 +1,408 @@
+<?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:
+   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 $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
+        $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);
+      }
+    }
+
+  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
+   */
+  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 = "\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 = $this->readint();
+  }
+
+  /**
+   * Loads the translation tables from the MO file into the cache
+   * If caching is enabled, also loads all strings into a cache
+   * to speed up translation lookups
+   * 
+   * @access private
+   */
+  function load_tables() {
+    if (is_array($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);
+    }
+  }
+
+  /**
+   * Sanitize plural form expression for use in PHP eval call.
+   *
+   * @access private
+   * @return string sanitized plural form expression
+   */
+  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 $res;
+  }
+
+  /**
+   * Parse full PO header and extract only plural forms line.
+   *
+   * @access private
+   * @return string verbatim plural form header field
+   */
+  function extract_plural_forms_header_from_po_header($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
+   */
+  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 $this->pluralheader;
+  }
+
+  /**
+   * Detects which plural form to take
+   *
+   * @access private
+   * @param n count
+   * @return int array index of the right plural form
+   */
+  function select_string($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 $plural;
+  }
+
+  /**
+   * Plural version of gettext
+   *
+   * @access public
+   * @param string single
+   * @param string plural
+   * @param string number
+   * @return translated plural form
+   */
+  function ngettext($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];
+      }
+    }
+  }
+
+}
+
+?>