Index: include/languages.php
===================================================================
--- include/languages.php	(revision 12904)
+++ include/languages.php	(working copy)
@@ -102,14 +102,20 @@
     $dir=bindtextdomain($domain,$dir);
 
     // set codeset in order to avoid gettext charset conversions
-    if (function_exists('bind_textdomain_codeset') 
-     && isset($languages[$sm_notAlias]['CHARSET'])) {
+    if (function_exists('bind_textdomain_codeset')) {
 
-        // Japanese translation uses different internal charset
-        if ($sm_notAlias == 'ja_JP') {
-            bind_textdomain_codeset ($domain_name, 'EUC-JP');
-        } else {
+        if (isset($languages[$sm_notAlias]['INTERNAL_CHARSET'])
+        && $languages[$sm_notAlias]['INTERNAL_CHARSET'] != '') {
+		
+            // some translations use different internal charset
+            bind_textdomain_codeset ($domain_name,
+                            $languages[$sm_notAlias]['INTERNAL_CHARSET']);
+
+        } else if (isset($languages[$sm_notAlias]['CHARSET'])
+               && isset($languages[$sm_notAlias]['CHARSET'])) {
+
             bind_textdomain_codeset ($domain_name, $languages[$sm_notAlias]['CHARSET']);
+
         }
 
     }
@@ -475,12 +481,22 @@
             putenv( "LANG=$longlocale" );
             putenv( "LANGUAGE=$longlocale" );
             putenv( "LC_NUMERIC=C" );
+        	/*
+             * FIXME: language-specific ones should be called with
+             *        vars in locale/$lang/setup.php (or need some
+             *        XTRA_CODE_code ?)
+             */
             if ($sm_notAlias=='tr_TR') putenv( "LC_CTYPE=C" );
         }
         // Workaround for plugins that use numbers with floating point
         // It might be removed if plugins use correct decimal delimiters
         // according to locale settings.
         setlocale(LC_NUMERIC, 'C');
+        /*  
+         * FIXME: language-specific ones should be called with
+         *        vars in locale/$lang/setup.php (or need some
+         *        XTRA_CODE_code ?)
+         */
         // Workaround for specific Turkish strtolower/strtoupper rules.
         // Many functions expect English conversion rules.
         if ($sm_notAlias=='tr_TR') setlocale(LC_CTYPE,'C');
@@ -516,50 +532,15 @@
         }
 
         $squirrelmail_language = $sm_notAlias;
-        if ($squirrelmail_language == 'ja_JP') {
-            header ('Content-Type: text/html; charset=EUC-JP');
-            if (!function_exists('mb_internal_encoding')) {
-                // Error messages can't be displayed here
-                $error = 1;
-                // Revert to English if possible.
-                if (function_exists('setPref')  && $username!='' && $data_dir!="") {
-                    setPref($data_dir, $username, 'language', "en_US");
-                    $error = 2;
-                }
-                // stop further execution in order not to get php errors on mb_internal_encoding().
-                return $error;
-            }
-            if (function_exists('mb_language')) {
-                mb_language('Japanese');
-            }
-            mb_internal_encoding('EUC-JP');
-            mb_http_output('pass');
+
+		if (isset($languages[$sm_notAlias]['XTRA_CODE'])
+		    && function_exists($languages[$sm_notAlias]['XTRA_CODE'] . '_header')) {
+			return call_user_func($languages[$sm_notAlias]['XTRA_CODE'] . '_header');
         } elseif ($squirrelmail_language == 'en_US') {
             header( 'Content-Type: text/html; charset=' . $default_charset );
         } else {
             header( 'Content-Type: text/html; charset=' . $languages[$sm_notAlias]['CHARSET'] );
         }
-        /**
-         * mbstring.func_overload fix (#929644).
-         *
-         * php mbstring extension can replace standard string functions with their multibyte
-         * equivalents. See http://www.php.net/ref.mbstring#mbstring.overload. This feature
-         * was added in php v.4.2.0
-         *
-         * Some SquirrelMail functions work with 8bit strings in bytes. If interface is forced
-         * to use mbstring functions and mbstring internal encoding is set to multibyte charset,
-         * interface can't trust regular string functions. Due to mbstring overloading design
-         * limits php scripts can't control this setting.
-         *
-         * This hack should fix some issues related to 8bit strings in passwords. Correct fix is
-         * to disable mbstring overloading. Japanese translation uses different internal encoding.
-         */
-        if ($squirrelmail_language != 'ja_JP' &&
-            function_exists('mb_internal_encoding') &&
-            check_php_version(4,2,0) &&
-            (int)ini_get('mbstring.func_overload')!=0) {
-            mb_internal_encoding('pass');
-        }
     }
     return 0;
 }
@@ -1030,6 +1011,7 @@
  * Possible 'variable' names:
  *  NAME      - Translation name in English
  *  CHARSET   - Encoding used by translation
+ *  INTERNAL_CHARSET - (if translation need extra charset for internal use)
  *  ALIAS     - used when 'language' is only short name and 'value' should provide long language name
  *  ALTNAME   - Native translation name. Any 8bit symbols must be html encoded.
  *  LOCALE    - Full locale name (in xx_XX.charset format). It can use array with more than one locale name since 1.4.5 and 1.5.1
Index: src/compose.php
===================================================================
--- src/compose.php	(revision 12904)
+++ src/compose.php	(working copy)
@@ -1221,36 +1221,27 @@
         showComposeButtonRow();
     }
 
-    $body_str = '';
-    if ($use_signature == true && $newmail == true && !isset($from_htmladdr_search)) {
-        $signature = $idents[$identity]['signature'];
+	$body_str = htmlspecialchars(decodeHeader($body,false,false));
 
-        if ($sig_first == '1') {
-            /*
-             * FIXME: test is specific to ja_JP translation implementation.
-             * This test might apply incorrect conversion to other translations, but
-             * use of 7bit iso-2022-jp charset in other translations might have other
-             * issues too.
-             */
-            if ($default_charset == 'iso-2022-jp') {
-                $body_str = "\n\n".($prefix_sig==true? "-- \n":'').mb_convert_encoding($signature, 'EUC-JP');
-            } else {
-                $body_str = "\n\n".($prefix_sig==true? "-- \n":'').decodeHeader($signature,false,false);
-            }
-            $body_str .= "\n\n".htmlspecialchars(decodeHeader($body,false,false));
-        } else {
-            $body_str = "\n\n".htmlspecialchars(decodeHeader($body,false,false));
-            // FIXME: test is specific to ja_JP translation implementation. See above comments.
-            if ($default_charset == 'iso-2022-jp') {
-                $body_str .= "\n\n".($prefix_sig==true? "-- \n":'').mb_convert_encoding($signature, 'EUC-JP');
-            } else {
-                $body_str .= "\n\n".($prefix_sig==true? "-- \n":'').decodeHeader($signature,false,false);
-            }
-        }
-    } else {
-        $body_str = htmlspecialchars(decodeHeader($body,false,false));
-    }
+	if ($use_signature == true && $newmail == true && !isset($from_htmladdr_search)) {
 
+		$signature = $idents[$identity]['signature'];
+		$sig_str  = (($prefix_sig == true) ? "--\n" : '');
+
+		$charset = $languages[$squirrelmail_language]['INTERNAL_CHARSET'];
+		if (isset($charset)) {
+			$sig_str .= mb_convert_encoding($signature, $charset);
+		} else {
+			$sig_str .= decodeHeader($signature, false, false);
+		}
+
+		if ($sig_first == '1') {
+			$body_str = "\n\n" . $sig_str . "\n\n" . $body_str;
+		} else {
+			$body_str = "\n\n" . $body_str . "\n\n" . $sig_str;
+		}
+	}
+
     $oTemplate->assign('editor_width', (int)$editor_size);
     $oTemplate->assign('editor_height', (int)$editor_height);
     $oTemplate->assign('input_onfocus', 'onfocus="'.join(' ', $onfocus_array).'"');
Index: functions/strings.php
===================================================================
--- functions/strings.php	(revision 12904)
+++ functions/strings.php	(working copy)
@@ -397,10 +397,16 @@
  * @since 1.0
  */
 function sqUnWordWrap(&$body) {
-    global $squirrelmail_language;
+    global $squirrelmail_language, $languages;
 
-    if ($squirrelmail_language == 'ja_JP') {
-        return;
+    // Use custom unwrapping function, if translation provides it
+    if (isset($languages[$squirrelmail_language]['XTRA_CODE']) &&
+        function_exists($languages[$squirrelmail_language]['XTRA_CODE'] . '_unwordwrap')) {
+        if (mb_detect_encoding($body) != 'ASCII') {
+            $body = call_user_func($languages[$squirrelmail_language]['XTRA_CODE'] . '_unwor
+dwrap', $body);
+            return;
+        }
     }
 
     $lines = explode("\n", $body);
@@ -1097,23 +1103,14 @@
     // default option
     if (is_null($charset)) return strlen($str);
 
-    // lowercase charset name
-    $charset=strtolower($charset);
+    // canonicalize and auto-detect (using cache) charset name
+    $charset = sq_get_auto_charset($charset);
 
-    // use automatic charset detection, if function call asks for it
-    if ($charset=='auto') {
-        global $default_charset, $squirrelmail_language;
-        set_my_charset();
-        $charset=$default_charset;
-        if ($squirrelmail_language=='ja_JP') $charset='euc-jp';
-    }
-
-    // Use mbstring only with listed charsets
-    $aList_of_mb_charsets=array('utf-8','big5','gb2312','gb18030','euc-jp','euc-cn','euc-tw','euc-kr');
-
     // calculate string length according to charset
-    if (in_array($charset,$aList_of_mb_charsets) && in_array($charset,sq_mb_list_encodings())) {
+    if (sq_need_mb($charset)) {
+
         $real_length = mb_strlen($str,$charset);
+
     } else {
         // own strlen detection code is removed because missing strpos,
         // strtoupper and substr implementations break string wrapping.
@@ -1168,33 +1165,10 @@
  * @link http://www.php.net/mb_substr
  */
 function sq_substr($string,$start,$length,$charset='auto') {
-    // use automatic charset detection, if function call asks for it
-    static $charset_auto, $bUse_mb;
 
-    if ($charset=='auto') {
-        if (!isset($charset_auto)) {
-            global $default_charset, $squirrelmail_language;
-            set_my_charset();
-            $charset=$default_charset;
-            if ($squirrelmail_language=='ja_JP') $charset='euc-jp';
-            $charset_auto = $charset;
-        } else {
-            $charset = $charset_auto;
-        }
-    }
-    $charset = strtolower($charset);
+    $charset = sq_get_auto_charset($charset);
 
-    // in_array call is expensive => do it once and use a static var for
-    // storing the results
-    if (!isset($bUse_mb)) {
-        if (in_array($charset,sq_mb_list_encodings())) {
-            $bUse_mb = true;
-        } else {
-            $bUse_mb = false;
-        }
-    }
-
-    if ($bUse_mb) {
+    if (sq_need_mb($charset)) {
         return mb_substr($string,$start,$length,$charset);
     }
     // TODO: add mbstring independent code
@@ -1216,32 +1190,10 @@
  * @link http://www.php.net/mb_strpos
  */
 function sq_strpos($haystack,$needle,$offset,$charset='auto') {
-    // use automatic charset detection, if function call asks for it
-    static $charset_auto, $bUse_mb;
 
-    if ($charset=='auto') {
-        if (!isset($charset_auto)) {
-            global $default_charset, $squirrelmail_language;
-            set_my_charset();
-            $charset=$default_charset;
-            if ($squirrelmail_language=='ja_JP') $charset='euc-jp';
-            $charset_auto = $charset;
-        } else {
-            $charset = $charset_auto;
-        }
-    }
-    $charset = strtolower($charset);
+    $charset = sq_get_auto_charset($charset);
 
-    // in_array call is expensive => do it once and use a static var for
-    // storing the results
-    if (!isset($bUse_mb)) {
-        if (in_array($charset,sq_mb_list_encodings())) {
-            $bUse_mb = true;
-        } else {
-            $bUse_mb = false;
-        }
-    }
-    if ($bUse_mb) {
+    if (sq_need_mb($charset)) {
         return mb_strpos($haystack,$needle,$offset,$charset);
     }
     // TODO: add mbstring independent code
@@ -1261,36 +1213,12 @@
  * @link http://www.php.net/mb_strtoupper
  */
 function sq_strtoupper($string,$charset='auto') {
-    // use automatic charset detection, if function call asks for it
-    static $charset_auto, $bUse_mb;
 
-    if ($charset=='auto') {
-        if (!isset($charset_auto)) {
-            global $default_charset, $squirrelmail_language;
-            set_my_charset();
-            $charset=$default_charset;
-            if ($squirrelmail_language=='ja_JP') $charset='euc-jp';
-            $charset_auto = $charset;
-        } else {
-            $charset = $charset_auto;
-        }
-    }
-    $charset = strtolower($charset);
+    $charset = sq_get_auto_charset($charset);
 
-    // in_array call is expensive => do it once and use a static var for
-    // storing the results
-    if (!isset($bUse_mb)) {
-        if (function_exists('mb_strtoupper') &&
-            in_array($charset,sq_mb_list_encodings())) {
-            $bUse_mb = true;
-        } else {
-            $bUse_mb = false;
-        }
+    if (sq_need_mb($charset)) {
+        return mb_strtoupper($string, $charset);
     }
-
-    if ($bUse_mb) {
-        return mb_strtoupper($string,$charset);
-    }
     // TODO: add mbstring independent code
 
     // use vanilla string functions as last option
@@ -1318,3 +1246,58 @@
 function sq_trim_value ( &$value ) {
     $value = trim($value);
 }
+
+/*
+ * Use auto charset detection if required.
+ * Otherwise returns lower-cased charset.
+ */
+function sq_get_auto_charset($charset)
+{
+    static $charset_auto;
+
+    if ($charset=='auto') {
+
+        if (!isset($charset_auto)) {
+
+            global $default_charset;
+            global $squirrelmail_language, $languages;
+
+            set_my_charset();
+            $charset = $default_charset;
+
+            /* if some language needs specific internal charset, then use it. */
+            if (isset($languages[$squirrelmail_language]['INTERNAL_CHARSET'])) {
+                $charset = $languages[$squirrelmail_language]['INTERNAL_CHARSET'];
+            }
+
+            $charset_auto = $charset;
+
+        } else {
+
+            /* use cache if possible. */
+            $charset = $charset_auto;
+
+        }
+    }
+
+    return strtolower($charset);
+}
+
+/* 
+ *  Checks if the charset needs mb_* functions.
+ *  in_array() is expensible function, use cache as possible.
+ */
+function sq_need_mb($charset)
+{
+    static $bUse_mb;
+
+    if (!isset($bUse_mb)) {
+        if (in_array($charset, sq_mb_list_encodings())) {
+            $bUse_mb = true;
+        } else {
+            $bUse_mb = false;
+        }
+    }
+
+    return $bUse_mb;
+}
Index: functions/page_header.php
===================================================================
--- functions/page_header.php	(revision 12904)
+++ functions/page_header.php	(working copy)
@@ -96,17 +96,11 @@
         $header_tags .= $oTemplate->fetch_right_to_left_stylesheet_link();
     }
 
-    if ($squirrelmail_language == 'ja_JP') {
-        /*
-         * force correct detection of charset, when browser does not follow
-         * http content-type and tries to detect charset from page content.
-         * Shooting of browser's creator can't be implemented in php.
-         * We might get rid of it, if we follow http://www.w3.org/TR/japanese-xml/
-         * recommendations and switch to unicode.
-         */
-        $header_tags .= "<!-- \xfd\xfe -->\n";
-        $header_tags .= '<meta http-equiv="Content-type" content="text/html; charset=euc-jp" />' . "\n";
-    }
+	// Language specific header
+	if (isset($languages[$squirrelmail_language]['EXTRA_HEADER'])) {
+		$header_tags .= $languages[$squirrelmail_language]['EXTRA_HEADER'];
+	}
+
     if ($do_hook) {
         // NOTE! plugins here MUST assign output to template 
         //       and NOT echo anything directly!!  A common