--- loncom/localize/lonlocal.pm	2009/02/01 21:54:30	1.54
+++ loncom/localize/lonlocal.pm	2009/05/04 21:44:00	1.58
@@ -1,7 +1,7 @@
 # The LearningOnline Network with CAPA
 # Localization routines
 #
-# $Id: lonlocal.pm,v 1.54 2009/02/01 21:54:30 lueken Exp $
+# $Id: lonlocal.pm,v 1.58 2009/05/04 21:44:00 lueken Exp $
 #
 # Copyright Michigan State University Board of Trustees
 #
@@ -173,16 +173,14 @@ require Exporter;
 our @ISA = qw (Exporter);
 our @EXPORT = qw(mt mtn ns mt_user);
 
+my %mtcache=();
+
 # ========================================================= The language handle
 
-use vars qw($lh);
+use vars qw($lh $current_language);
 
 # ===================================================== The "MakeText" function
 
-######### Localize Cache
-my @localize_cache;
-#########
-
 sub mt (@) {
 #    open(LOG,'>>/home/www/loncapa/loncom/localize/localize/newphrases.txt');
 #    print LOG (@_[0]."\n");
@@ -195,18 +193,13 @@ sub mt (@) {
                 return $_[0];
             }
         } else {
-				######### Localize Cache
-				foreach my $e (@localize_cache)
-				{
-					if($_[0] eq $$e[0]) { return $$e[1]; }
-				}
-
-				if($#localize_cache == 100) { pop(@localize_cache); }
-				my $localize_entry = $lh->maketext(@_);
-				unshift(@localize_cache, [ @_, $localize_entry ] );
-				#########
-            
-	    		return $localize_entry;
+            if ($#_>0) { return $lh->maketext(@_); }
+            if ($mtcache{$current_language.':'.$_[0]}) {
+               return $mtcache{$current_language.':'.$_[0]};
+            }
+            my $translation=$lh->maketext(@_);
+            $mtcache{$current_language.':'.$_[0]}=$translation;
+            return $translation; 
         }
     } else {
 	if (wantarray) {
@@ -302,10 +295,13 @@ sub get_genlanguages {
 
 sub current_encoding {
     my $default='UTF-8';
-    if ($Apache::lonnet::env{'browser.os'} eq 'win' && 
-	$Apache::lonnet::env{'browser.type'} eq 'explorer') {
-        $default='ISO-8859-1';
-    }
+# UTF-8 character encoding needed for the whole LON-CAPA system
+# (interface language and homework problem content)
+# See Bugzilla 5702 vs. 2189 and 4067
+#    if ($Apache::lonnet::env{'browser.os'} eq 'win' && 
+#	$Apache::lonnet::env{'browser.type'} eq 'explorer') {
+#        $default='ISO-8859-1';
+#    }
     if ($lh) {
 	my $enc=$lh->maketext('char_encoding');
 	return ($enc eq 'char_encoding'?$default:$enc);
@@ -347,6 +343,7 @@ sub get_language_handle {
     my @languages=&preferred_languages();
     $ENV{'HTTP_ACCEPT_LANGUAGE'}='';
     $lh=Apache::localize->get_handle(@languages);
+    $current_language=&current_language();
     if ($r) {
 	$r->content_languages([&current_language()]);
     }
@@ -396,8 +393,11 @@ sub gettimezone {
     return 'local';
 }
 
+our $timezone_local;
+
 sub locallocaltime {
-    my ($thistime,$timezone) = @_;
+    my ($thistime,$timezone,$datetime) = @_;
+
     if (!defined($thistime) || $thistime eq '') {
 	return &mt('Never');
     }
@@ -410,8 +410,70 @@ sub locallocaltime {
         return &mt('Never');
     }
 
-    my $dt = DateTime->from_epoch(epoch => $thistime)
-                     ->set_time_zone(&gettimezone($timezone));
+   my $dt;
+   my $convert_time;
+
+   #### START # Speed up if this function is called often #### 
+   
+   # Is a $datetime parameter set?
+   if(defined($datetime)) {
+	# Check for an instance of a DateTime object
+   	if(!(defined $$datetime)) {
+		# No object, create one
+		$$datetime = DateTime->from_epoch(epoch => $thistime)
+       	                  ->set_time_zone(&gettimezone($timezone));
+		$dt = $$datetime;
+	   } else {
+		# If the return-value is "local", we have to convert it for DateTime	
+	
+		# Converts the "local"-String only once
+		if(!defined($timezone_local))	
+		{
+			$timezone_local = DateTime::TimeZone->new( name => gettimezone('local'))->name();
+		}
+
+		my $timezone_now;
+
+		if(gettimezone($timezone) == 'local')
+		{
+			$timezone_now = $timezone_local;
+		} else {
+			$timezone_now = gettimezone($timezone);
+		}
+
+		# Has the timezone changed?
+		if($timezone_now eq $$datetime->time_zone_short_name() ||
+		   $timezone_now eq $$datetime->time_zone_long_name())
+		{
+			# There is already an object (dereference)
+			$dt = $$datetime;
+		
+			# We need this as temporary value	
+			$convert_time = DateTime->from_epoch( epoch => $thistime );
+        	                                #->set_time_zone('floating');
+ 
+			# Preventing a set_time_zone call (time consuming)	
+			# Using old instance of DateTime with timezone
+			$dt->set( year => $convert_time->year(),
+				  month => $convert_time->month(),
+				  day => $convert_time->day(),
+				  hour => $convert_time->hour(),
+				  minute => $convert_time->minute(),
+				  second => $convert_time->second() );
+   		} else {
+			# The timezone has changed since last time
+			$$datetime = DateTime->from_epoch(epoch => $thistime)
+                          ->set_time_zone(&gettimezone($timezone));
+			$dt = $$datetime;
+		} 
+	}
+   } else {
+	# There is no $datetime parameter
+	$dt = DateTime->from_epoch(epoch => $thistime)
+                      ->set_time_zone(&gettimezone($timezone));
+   }
+   #### END # Speed up if this function is called often ####
+
     if ((&current_language=~/^en/) || (!$lh)) {
 
 	return $dt->strftime("%a %b %e %I:%M:%S %P %Y (%Z)");