diff --git a/doc/lftp.1 b/doc/lftp.1
index d5d408f..9222795 100644
--- a/doc/lftp.1
+++ b/doc/lftp.1
@@ -1748,10 +1748,15 @@ is applied. It is never used if mirror:exclude-regex is empty.
 .BR mirror:no-empty-dirs " (boolean)"
 when true, mirror doesn't create empty directories (like \-\-no\-empty\-dirs option).
 .TP
+.BR mirror:sort-by " (string)"
+specifies order of file transfers. Valid values are: name, name-desc, size, size-desc,
+date, date-desc. When the value is name or name-desc, then mirror:order setting also
+affects the order or transfers.
+.TP
 .BR mirror:order " (list of patterns)"
-specifies order of file transfers. E.g. setting this to "*.sfv *.sum" makes mirror to
+specifies order of file transfers when sorting by name. E.g. setting this to "*.sfv *.sum" makes mirror to
 transfer files matching *.sfv first, then ones matching *.sum and then all other
-files. To process directories after other files, add "*/" to end of pattern list.
+files. To process directories after other files, add "*/" to the end of pattern list.
 .TP
 .BR mirror:parallel-directories " (boolean)"
 if true, mirror will start processing of several directories in parallel
diff --git a/po/pl.po b/po/pl.po
index d569428..89e8b11 100644
--- a/po/pl.po
+++ b/po/pl.po
@@ -7,10 +7,10 @@
 #
 msgid ""
 msgstr ""
-"Project-Id-Version: lftp 4.4.16\n"
+"Project-Id-Version: lftp 4.5.3\n"
 "Report-Msgid-Bugs-To: lftp-bugs@lftp.yar.ru\n"
 "POT-Creation-Date: 2014-07-06 16:15+0400\n"
-"PO-Revision-Date: 2014-05-18 06:54+0200\n"
+"PO-Revision-Date: 2014-07-13 14:15+0200\n"
 "Last-Translator: Jakub Bogusz <qboosh@pld-linux.org>\n"
 "Language-Team: Polish <translation-team-pl@lists.sourceforge.net>\n"
 "Language: pl\n"
@@ -1152,12 +1152,10 @@ msgstr ""
 "uczyni dopełnianie nazw plików nie rozpoznającym wielkości liter.\n"
 
 #: src/commands.cc:216
-#, fuzzy
 msgid "debug [OPTS] [<level>|off]"
-msgstr "debug [<poziom>|off] [-o <plik>]"
+msgstr "debug [OPCJE] [<poziom>|off]"
 
 #: src/commands.cc:217
-#, fuzzy
 msgid ""
 "Set debug level to given value or turn debug off completely.\n"
 " -o <file>  redirect debug output to the file\n"
@@ -1165,8 +1163,11 @@ msgid ""
 " -p  show PID\n"
 " -t  show timestamps\n"
 msgstr ""
-"Ustaw poziom debugowania na daną wartość lub wyłącz zupełnie.\n"
-" -o <plik>  przekieruj wyjście debugowania do pliku.\n"
+"Ustaw poziom diagnostyki na daną wartość lub wyłącz zupełnie.\n"
+" -o <plik>  przekieruj wyjście diagnostyki do pliku.\n"
+" -c  wypisuj kontekst komunikatu\n"
+" -p  wypisuj PID\n"
+" -t  wypisuj znaczniki czasu\n"
 
 #: src/commands.cc:222
 msgid "du [options] <dirs>"
@@ -1477,12 +1478,10 @@ msgstr ""
 "podano nazw obu katalogów, to będą użyte bieżące katalogi lokalny i zdalny.\n"
 
 #: src/commands.cc:339
-#, fuzzy
 msgid "mkdir [OPTS] <dirs>"
-msgstr "mkdir [-p] <katalogi>"
+msgstr "mkdir [OPCJE] <katalogi>"
 
 #: src/commands.cc:340
-#, fuzzy
 msgid ""
 "Make remote directories\n"
 " -p  make all levels of path\n"
@@ -1490,6 +1489,7 @@ msgid ""
 msgstr ""
 "Utwórz zdalne katalogi\n"
 " -p  tworzy wszystkie poziomy ścieżki\n"
+" -f  ciche działanie, bez komunikatów\n"
 
 #: src/commands.cc:343
 msgid "module name [args]"
@@ -2378,9 +2378,9 @@ msgid "unsupported network protocol"
 msgstr "protokół nie jest obsługiwany"
 
 #: src/ftpclass.cc:2133 src/ftpclass.cc:2228
-#, fuzzy, c-format
+#, c-format
 msgid "Data socket error (%s) - reconnecting"
-msgstr "Błąd połączenia (%s) - powtórne łączenie"
+msgstr "Błąd gniazda danych (%s) - powtórne łączenie"
 
 #: src/ftpclass.cc:2161
 #, c-format
@@ -2700,13 +2700,12 @@ msgid "peer unexpectedly closed connection after %s"
 msgstr "druga strona nieoczekiwanie zamknęła połączenie po %s"
 
 #: src/Torrent.cc:2903 src/Torrent.cc:3020
-#, fuzzy
 msgid "peer unexpectedly closed connection"
-msgstr "druga strona nieoczekiwanie zamknęła połączenie po %s"
+msgstr "druga strona nieoczekiwanie zamknęła połączenie"
 
 #: src/Torrent.cc:2905 src/Torrent.cc:2906
 msgid "peer closed connection (before handshake)"
-msgstr "druga strona zamknęła połączenie (przed jego ustanowieniem)"
+msgstr "druga strona zamknęła połączenie (przed przywitaniem)"
 
 #: src/Torrent.cc:2909 src/Torrent.cc:3022 src/Torrent.cc:3023
 msgid "invalid peer response format"
@@ -2732,15 +2731,15 @@ msgstr "Przyjęto połączenie od [%s]:%d"
 #: src/Torrent.cc:3552
 #, c-format
 msgid "peer sent unknown info_hash=%s in handshake"
-msgstr ""
+msgstr "druga strona wysłała nieznane info_hash=%s przy przywitaniu"
 
 #: src/Torrent.cc:3576
 msgid "peer handshake timeout"
-msgstr "upłynął limit czasu nawiązywania połączenia z drugą stroną"
+msgstr "upłynął limit czasu przywitania z drugą stroną"
 
 #: src/Torrent.cc:3588
 msgid "peer short handshake"
-msgstr "nawiązanie połączenia z drugą stroną zostało ucięte"
+msgstr "przywitanie z drugą stroną zostało ucięte"
 
 #: src/Torrent.cc:3590
 msgid "peer closed just accepted connection"
diff --git a/src/FileSet.cc b/src/FileSet.cc
index 389578a..6380a68 100644
--- a/src/FileSet.cc
+++ b/src/FileSet.cc
@@ -232,6 +232,21 @@ void FileSet::Sort(sort_e newsort, bool casefold, bool reverse)
    }
 }
 
+// reverse current sort order
+void FileSet::ReverseSort()
+{
+   if(!sorted) {
+      Sort(BYNAME,false,true);
+      return;
+   }
+   int i=0;
+   int j=sorted.length()-1;
+   while(i<j) {
+      sorted[i]=replace_value(sorted[j],sorted[i]);
+      ++i,--j;
+   }
+}
+
 /* Remove the current sort, allowing new entries to be added.
  * (Nothing uses this ... */
 void FileSet::Unsort()
diff --git a/src/FileSet.h b/src/FileSet.h
index 7c3ac2a..155536f 100644
--- a/src/FileSet.h
+++ b/src/FileSet.h
@@ -180,6 +180,7 @@ public:
    void  Sort(sort_e newsort, bool casefold=false, bool reverse=false);
    void  Unsort();
    void	 SortByPatternList(const char *list_c);
+   void	 ReverseSort();
 
    void	 Exclude(const char *prefix,const PatternSet *x);
    void	 ExcludeDots();
diff --git a/src/Fish.cc b/src/Fish.cc
index d172a20..29ba4c6 100644
--- a/src/Fish.cc
+++ b/src/Fish.cc
@@ -98,6 +98,15 @@ int Fish::Do()
       timeout_timer.Reset(send_buf->EventTime());
    if(recv_buf)
       timeout_timer.Reset(recv_buf->EventTime());
+   if(pty_send_buf)
+      timeout_timer.Reset(pty_send_buf->EventTime());
+   if(pty_recv_buf)
+      timeout_timer.Reset(pty_recv_buf->EventTime());
+
+   // check for timeout only if there should be connection activity.
+   if(state!=DISCONNECTED && (state!=CONNECTED || !RespQueueIsEmpty())
+   && mode!=CLOSED && CheckTimeout())
+      return MOVED;
 
    if((state==FILE_RECV || state==FILE_SEND)
    && rate_limit==0)
@@ -275,14 +284,6 @@ int Fish::Do()
    case DONE:
       break;
    }
-   if(m==MOVED)
-      return MOVED;
-   if(send_buf)
-      timeout_timer.Reset(send_buf->EventTime());
-   if(recv_buf)
-      timeout_timer.Reset(recv_buf->EventTime());
-   if(CheckTimeout())
-      return MOVED;
    return m;
 }
 
diff --git a/src/MirrorJob.cc b/src/MirrorJob.cc
index a19ff8e..eb148f1 100644
--- a/src/MirrorJob.cc
+++ b/src/MirrorJob.cc
@@ -589,10 +589,16 @@ void  MirrorJob::InitSets(const FileSet *source,const FileSet *dest)
    if(!(flags&DELETE))
       to_transfer->SubtractAny(to_rm_mismatched);
 
-   to_transfer->SortByPatternList(ResMgr::Query("mirror:order",0));
-   to_transfer->CountBytes(&bytes_to_transfer);
-   if(parent_mirror)
-      parent_mirror->AddBytesToTransfer(bytes_to_transfer);
+   const char *sort_by=ResMgr::Query("mirror:sort-by",0);
+   bool desc=strstr(sort_by,"-desc");
+   if(!strncmp(sort_by,"name",4))
+      to_transfer->SortByPatternList(ResMgr::Query("mirror:order",0));
+   else if(!strncmp(sort_by,"date",4))
+      to_transfer->Sort(FileSet::BYDATE);
+   else if(!strncmp(sort_by,"size",4))
+      to_transfer->Sort(FileSet::BYSIZE,false,true);
+   if(desc)
+      to_transfer->ReverseSort();
 
    int dir_count=0;
    to_transfer->Count(&dir_count,NULL,NULL,NULL);
@@ -851,10 +857,16 @@ int   MirrorJob::Do()
       stats.dirs++;
 
       InitSets(source_set,target_set);
+
+      to_transfer->CountBytes(&bytes_to_transfer);
+      if(parent_mirror)
+	 parent_mirror->AddBytesToTransfer(bytes_to_transfer);
+
       to_rm->Count(&stats.del_dirs,&stats.del_files,&stats.del_symlinks,&stats.del_files);
       to_rm->rewind();
       to_rm_mismatched->Count(&stats.del_dirs,&stats.del_files,&stats.del_symlinks,&stats.del_files);
       to_rm_mismatched->rewind();
+
       set_state(TARGET_REMOVE_OLD_FIRST);
       goto TARGET_REMOVE_OLD_FIRST_label;
 
diff --git a/src/PollVec.cc b/src/PollVec.cc
index a18b517..e1d72fb 100644
--- a/src/PollVec.cc
+++ b/src/PollVec.cc
@@ -31,7 +31,7 @@ static inline bool operator<(const timeval& a,const timeval& b)
 void PollVec::AddTimeoutU(unsigned t)
 {
    struct timeval new_timeout={t/1000000,t%1000000};
-   if(new_timeout<tv_timeout)
+   if(tv_timeout.tv_sec<0 || new_timeout<tv_timeout)
       SetTimeout(new_timeout);
 }
 
diff --git a/src/ProcWait.cc b/src/ProcWait.cc
index 0a065ad..d3dfec4 100644
--- a/src/ProcWait.cc
+++ b/src/ProcWait.cc
@@ -24,7 +24,14 @@
 #include "ProcWait.h"
 #include "SignalHook.h"
 
-ProcWait *ProcWait::chain=0;
+xmap<ProcWait*> ProcWait::all_proc;
+
+const xstring& ProcWait::proc_key(pid_t p)
+{
+   static xstring tmp_key;
+   tmp_key.nset((const char*)&p,sizeof(p));
+   return tmp_key;
+}
 
 int ProcWait::Do()
 {
@@ -100,27 +107,19 @@ int ProcWait::Kill(int sig)
 }
 
 ProcWait::ProcWait(pid_t p)
+   : pid(p)
 {
    auto_die=false;
-   pid=p;
    status=RUNNING;
    term_info=-1;
    saved_errno=0;
 
-   next=chain;
-   chain=this;
+   all_proc.add(proc_key(pid),this);
 }
 
 ProcWait::~ProcWait()
 {
-   for(ProcWait **scan=&chain; *scan; scan=&(*scan)->next)
-   {
-      if(*scan==this)
-      {
-	 *scan=next;
-	 return;
-      }
-   }
+   all_proc.remove(proc_key(pid));
 }
 
 void ProcWait::SIGCHLD_handler(int sig)
@@ -130,16 +129,9 @@ void ProcWait::SIGCHLD_handler(int sig)
    pid_t pp=waitpid(-1,&info,WUNTRACED|WNOHANG);
    if(pp==-1)
       return;
-   for(ProcWait *scan=chain; scan; scan=scan->next)
-   {
-      if(scan->pid==pp)
-      {
-	 scan->handle_info(info);
-	 return;
-      }
-   }
-   // no WaitProc for the pid. Probably the process died too fast,
-   // but next waitpid should take care of it.
+   ProcWait *w=all_proc.lookup(proc_key(pp));
+   if(w && w->handle_info(info))
+      w->Timeout(0);
 }
 
 void ProcWait::Signal(bool yes)
@@ -156,6 +148,6 @@ void ProcWait::Signal(bool yes)
 void ProcWait::DeleteAll()
 {
    Signal(false);
-   for(ProcWait *scan=chain; scan; scan=scan->next)
-      Delete(scan);
+   for(ProcWait *w=all_proc.each_begin(); w; w=all_proc.each_next())
+      Delete(w);
 }
diff --git a/src/ProcWait.h b/src/ProcWait.h
index d6f0bad..651bc21 100644
--- a/src/ProcWait.h
+++ b/src/ProcWait.h
@@ -23,6 +23,7 @@
 #include <sys/types.h>
 #include <signal.h>
 #include "SMTask.h"
+#include "xmap.h"
 
 class ProcWait : public SMTask
 {
@@ -35,10 +36,10 @@ public:
    };
 
 protected:
-   static ProcWait *chain;
-   ProcWait *next;
+   static xmap<ProcWait*> all_proc;
+   static const xstring& proc_key(pid_t p); // make key for xmap
 
-   pid_t pid;
+   const pid_t pid;
    State status;
    int	 term_info;
    int	 saved_errno;
diff --git a/src/Ref.h b/src/Ref.h
index 8731089..c96ee96 100644
--- a/src/Ref.h
+++ b/src/Ref.h
@@ -51,4 +51,22 @@ public:
 
 template<typename T> const Ref<T> Ref<T>::null;
 
+template<typename T> class RefToArray : public Ref<T>
+{
+   RefToArray<T>(const RefToArray<T>&);  // disable cloning
+   void operator=(const RefToArray<T>&);   // and assignment
+
+public:
+   RefToArray<T>() {}
+   RefToArray<T>(T *p) : Ref<T>(p) {}
+   ~RefToArray<T>() { delete[] Ref<T>::ptr; Ref<T>::ptr=0; }
+   void operator=(T *p) { delete[] Ref<T>::ptr; Ref<T>::ptr=p; }
+   T& operator[](unsigned i) const { return Ref<T>::ptr[i]; }
+
+   static const RefToArray<T> null;
+};
+
+template<typename T> const RefToArray<T> RefToArray<T>::null;
+
+
 #endif
diff --git a/src/SFtp.cc b/src/SFtp.cc
index 8e6d0d5..3225701 100644
--- a/src/SFtp.cc
+++ b/src/SFtp.cc
@@ -915,11 +915,7 @@ void SFtp::HandleExpect(Expect *e)
 	 for(int i=0; i<r->GetCount(); i++)
 	 {
 	    const NameAttrs *a=r->GetNameAttrs(i);
-	    if(!file_set)
-	       file_set=new FileSet;
 	    FileInfo *info=MakeFileInfo(a);
-	    if(info)
-	       file_set->Add(info);
 	    if(mode==LIST)
 	    {
 	       file_buf->Put(a->name);
@@ -941,6 +937,12 @@ void SFtp::HandleExpect(Expect *e)
 		  file_buf->Put("\n");
 	       }
 	    }
+	    if(info)
+	    {
+	       if(!file_set)
+		  file_set=new FileSet;
+	       file_set->Add(info);
+	    }
 	 }
 	 if(r->Eof())
 	    goto eof;
diff --git a/src/Torrent.cc b/src/Torrent.cc
index ffe6433..270bbd6 100644
--- a/src/Torrent.cc
+++ b/src/Torrent.cc
@@ -278,6 +278,10 @@ Torrent::Torrent(const char *mf,const char *c,const char *od)
    dht_announce_timer.Stop();
 }
 
+Torrent::~Torrent()
+{
+}
+
 bool Torrent::TrackersDone() const
 {
    if(shutting_down && shutting_down_timer.Stopped())
@@ -318,6 +322,8 @@ void Torrent::PrepareToDie()
       RemoveTorrent(this);
       if(GetTorrentsCount()==0) {
 	 StopListener();
+	 StopDHT();
+	 StopListenerUDP();
 	 fd_cache=0;
 	 black_list=0;
       }
@@ -348,9 +354,7 @@ double Torrent::GetRatio() const
 
 void Torrent::SetDownloader(unsigned piece,unsigned block,const TorrentPeer *o,const TorrentPeer *n)
 {
-   const TorrentPeer*& downloader=piece_info[piece]->downloader[block];
-   if(downloader==o)
-      downloader=n;
+   piece_info[piece].set_downloader(block,o,n,BlocksInPiece(piece));
 }
 
 BeNode *Torrent::Lookup(xmap_p<BeNode>& dict,const char *name,BeNode::be_type_t type)
@@ -421,25 +425,18 @@ void Torrent::ValidatePiece(unsigned p)
 	 complete_pieces--;
 	 my_bitfield->set_bit(p,0);
       }
-      piece_info[p]->block_map.clear();
+      SetBlocksAbsent(p);
    } else {
       LogNote(11,"piece %u ok",p);
       if(!my_bitfield->get_bit(p)) {
 	 total_left-=PieceLength(p);
 	 complete_pieces++;
 	 my_bitfield->set_bit(p,1);
+	 piece_info[p].free_block_map();
       }
    }
 }
 
-bool TorrentPiece::has_a_downloader() const
-{
-   for(int i=0; i<downloader.count(); i++)
-      if(downloader[i])
-	 return true;
-   return false;
-}
-
 template<typename T>
 static inline int cmp(T a,T b)
 {
@@ -453,8 +450,8 @@ static inline int cmp(T a,T b)
 static Torrent *cmp_torrent;
 int Torrent::PiecesNeededCmp(const unsigned *a,const unsigned *b)
 {
-   int ra=cmp_torrent->piece_info[*a]->sources_count;
-   int rb=cmp_torrent->piece_info[*b]->sources_count;
+   int ra=cmp_torrent->piece_info[*a].get_sources_count();
+   int rb=cmp_torrent->piece_info[*b].get_sources_count();
    int c=cmp(ra,rb);
    if(c) return c;
    return cmp(*a,*b);
@@ -721,7 +718,7 @@ void Torrent::SetMetadata(const xstring& md)
    }
 
    BeNode *b_piece_length=Lookup(info,"piece length",BeNode::BE_INT);
-   if(!b_piece_length)
+   if(!b_piece_length || b_piece_length->num<1024 || b_piece_length->num>INT_MAX/4)
       return;
    piece_length=b_piece_length->num;
    LogNote(4,"Piece length is %u",piece_length);
@@ -744,7 +741,7 @@ void Torrent::SetMetadata(const xstring& md)
    if(!files) {
       single_file=true;
       BeNode *length=Lookup(info,"length",BeNode::BE_INT);
-      if(!length)
+      if(!length || length->num<0)
 	 return;
       total_length=length->num;
    } else {
@@ -764,9 +761,12 @@ void Torrent::SetMetadata(const xstring& md)
 	    return;
 	 if(!Lookup(files->list[i]->dict,"path",BeNode::BE_LIST))
 	    return;
+	 if(f->num<0)
+	    return;
 	 total_length+=f->num;
       }
    }
+   this->files=new TorrentFiles(files,this);
    LogNote(4,"Total length is %llu",total_length);
    total_left=total_length;
 
@@ -800,16 +800,18 @@ void Torrent::SetMetadata(const xstring& md)
    SaveMetadata();
 
    my_bitfield=new BitField(total_pieces);
-   for(unsigned p=0; p<total_pieces; p++)
-      piece_info.append(new TorrentPiece(BlocksInPiece(p)));
+
+   blocks_in_piece=(piece_length+BLOCK_SIZE-1)/BLOCK_SIZE;
+   blocks_in_last_piece=(last_piece_length+BLOCK_SIZE-1)/BLOCK_SIZE;
+
+   piece_info=new TorrentPiece[total_pieces]();
 
    if(!force_valid) {
       validate_index=0;
       validating=true;
       recv_rate.Reset();
    } else {
-      for(unsigned i=0; i<total_pieces; i++)
-	 my_bitfield->set_bit(i,1);
+      my_bitfield->set_range(0,total_pieces,1);
       complete_pieces=total_pieces;
       total_left=0;
       complete=true;
@@ -927,7 +929,7 @@ void Torrent::CalcPiecesStats()
    for(unsigned i=0; i<total_pieces; i++) {
       if(my_bitfield->get_bit(i))
 	 continue;
-      unsigned sc=piece_info[i]->sources_count;
+      unsigned sc=piece_info[i].get_sources_count();
       if(min_piece_sources>sc)
 	 min_piece_sources=sc;
       if(sc==0)
@@ -945,12 +947,13 @@ void Torrent::RebuildPiecesNeeded()
    bool enter_end_game=true;
    for(unsigned i=0; i<total_pieces; i++) {
       if(!my_bitfield->get_bit(i)) {
-	 if(!piece_info[i]->has_a_downloader())
+	 if(!piece_info[i].has_a_downloader())
 	    enter_end_game=false;
-	 if(piece_info[i]->sources_count==0)
+	 if(piece_info[i].has_no_sources())
 	    continue;
 	 pieces_needed.append(i);
       }
+      piece_info[i].cleanup();
    }
    if(!end_game && enter_end_game) {
       LogNote(1,"entering End Game mode");
@@ -1084,6 +1087,8 @@ int Torrent::Do()
 	       a.sa.sa_family=AF_INET6;
 	       if(inet_pton(AF_INET6,b_ip->str,&a.in6.sin6_addr)<=0)
 		  continue;
+	       if(b_port->num<=0 || b_port->num>=0x10000)
+		  continue;
 	       a.set_port(b_port->num);
 	       dht_ipv6->SendPing(a);
 	    } else
@@ -1092,6 +1097,8 @@ int Torrent::Do()
 	       a.sa.sa_family=AF_INET;
 	       if(!inet_aton(b_ip->str,&a.in.sin_addr))
 		  continue;
+	       if(b_port->num<=0 || b_port->num>=0x10000)
+		  continue;
 	       a.set_port(b_port->num);
 	       dht->SendPing(a);
 	    }
@@ -1249,24 +1256,51 @@ const char *Torrent::MakePath(BeNode *p) const
 }
 const char *Torrent::FindFileByPosition(unsigned piece,unsigned begin,off_t *f_pos,off_t *f_tail) const
 {
-   const BeNode *files=info->lookup("files",BeNode::BE_LIST);
    off_t target_pos=(off_t)piece*piece_length+begin;
+   TorrentFile *file=files->FindByPosition(target_pos);
+   if(!file)
+      return 0;
+
+   *f_pos=target_pos-file->pos;
+   *f_tail=file->length-*f_pos;
+
+   return file->path;
+}
+
+TorrentFiles::TorrentFiles(const BeNode *files,const Torrent *t)
+{
    if(!files) {
-      *f_pos=target_pos;
-      *f_tail=total_length-target_pos;
-      return name;
+      grow_space(1);
+      set_length(1);
+      file(0)->set(t->GetName(),0,t->TotalLength());
    } else {
+      int count=files->list.length();
+      grow_space(count);
+      set_length(count);
       off_t scan_pos=0;
-      for(int i=0; i<files->list.length(); i++) {
-	 off_t file_length=files->list[i]->lookup_int("length");
-	 if(scan_pos<=target_pos && scan_pos+file_length>target_pos) {
-	    *f_pos=target_pos-scan_pos;
-	    *f_tail=file_length-*f_pos;
-	    return MakePath(files->list[i]);
-	 }
+      for(int i=0; i<count; i++) {
+	 BeNode *node=files->list[i];
+	 off_t file_length=node->lookup_int("length");
+	 file(i)->set(t->MakePath(node),scan_pos,file_length);
 	 scan_pos+=file_length;
       }
    }
+   qsort(pos_cmp);
+}
+TorrentFile *TorrentFiles::FindByPosition(off_t pos)
+{
+   int i=0;
+   int j=length()-1;
+   while(i<=j) {
+      // invariant: the target element is in the range [i,j]
+      int m=(i+j)/2;
+      if(file(m)->contains_pos(pos))
+	 return file(m);
+      if(file(m)->pos>pos)
+	 j=m-1;
+      else
+	 i=m+1;
+   }
    return 0;
 }
 
@@ -1485,9 +1519,9 @@ void Torrent::StoreBlock(unsigned piece,unsigned begin,unsigned len,const char *
    }
 
    while(bc-->0) {
-      piece_info[piece]->block_map.set_bit(b++,1);
+      SetBlockPresent(piece,b++);
    }
-   if(piece_info[piece]->block_map.has_all_set() && !my_bitfield->get_bit(piece)) {
+   if(AllBlocksPresent(piece) && !my_bitfield->get_bit(piece)) {
       ValidatePiece(piece);
       if(!my_bitfield->get_bit(piece)) {
 	 LogError(0,"new piece %u digest mismatch",piece);
@@ -2021,12 +2055,12 @@ int TorrentPeer::SendDataRequests(unsigned p)
    unsigned blocks=parent->BlocksInPiece(p);
    unsigned bytes_allowed=BytesAllowed(RateLimit::GET);
    for(unsigned b=0; b<blocks; b++) {
-      if(parent->piece_info[p]->block_map.get_bit(b))
+      if(parent->BlockPresent(p,b))
 	 continue;
-      if(parent->piece_info[p]->downloader[b]) {
+      if(parent->piece_info[p].downloader_for(b)) {
 	 if(!parent->end_game)
 	    continue;
-	 if(parent->piece_info[p]->downloader[b]==this)
+	 if(parent->piece_info[p].downloader_for(b)==this)
 	    continue;
 	 if(FindRequest(p,b*Torrent::BLOCK_SIZE)>=0)
 	    continue;
@@ -2118,8 +2152,7 @@ void TorrentPeer::SendDataRequests()
 	 if(parent->my_bitfield->get_bit(p))
 	    continue;
 	 // add some randomness, so that different instances don't synchronize
-	 if(!parent->piece_info[p]->block_map.has_any_set()
-	 && random()/13%16==0)
+	 if(parent->AllBlocksAbsent(p) && random()/13%16==0)
 	    continue;
 	 if(SendDataRequests(p)>0)
 	    return;
@@ -2233,7 +2266,7 @@ unsigned TorrentPeer::GetLastPiece() const
    unsigned p=last_piece;
    // continue if have any blocks already
    if(p!=NO_PIECE && !parent->my_bitfield->get_bit(p)
-   && parent->piece_info[p]->block_map.has_any_set()
+   && parent->AnyBlocksPresent(p)
    && peer_bitfield->get_bit(p))
       return p;
    p=parent->last_piece;
@@ -2302,11 +2335,11 @@ void TorrentPeer::SetPieceHaving(unsigned p,bool have)
    int diff = (have - peer_bitfield->get_bit(p));
    if(!diff)
       return;
-   parent->piece_info[p]->sources_count+=diff;
+   parent->piece_info[p].add_sources_count(diff);
    peer_complete_pieces+=diff;
    peer_bitfield->set_bit(p,have);
 
-   if(parent->piece_info[p]->sources_count==0)
+   if(parent->piece_info[p].get_sources_count()==0)
       parent->SetPieceNotWanted(p);
    if(have && send_buf && !am_interested && !parent->my_bitfield->get_bit(p)
    && parent->NeedMoreUploaders()) {
@@ -2641,7 +2674,7 @@ void TorrentPeer::HandleExtendedMessage(PacketExtended *pp)
 	 return;
       }
       BeNode *piece=pp->data->lookup("piece",BeNode::BE_INT);
-      if(!piece) {
+      if(!piece || piece->num<0 || piece->num>=INT_MAX/Torrent::BLOCK_SIZE) {
 	 SetError("ut_metadata piece bad or missing");
 	 return;
       }
@@ -2692,6 +2725,9 @@ void TorrentPeer::HandleExtendedMessage(PacketExtended *pp)
 	 }
 	 case UT_METADATA_REJECT:
 	    break;
+	 default:
+	    SetError("ut_metadata msg_type invalid value");
+	    return;
       }
    } else if(pp->code==MSG_EXT_PEX) {
       if(!pex.recv_timer.Stopped())
@@ -3322,14 +3358,16 @@ bool BitField::has_all_set(int from,int to) const {
 	 return false;
    return true;
 }
-
+void BitField::set_range(int from,int to,bool value) {
+   for(int i=from; i<to; i++)
+      set_bit(i,value);
+}
 
 void TorrentBlackList::check_expire()
 {
    for(Timer *e=bl.each_begin(); e; e=bl.each_next()) {
       if(e->Stopped()) {
 	 Log::global->Format(4,"---- black-delisting peer %s\n",bl.each_key().get());
-	 delete e;
 	 bl.remove(bl.each_key());
       }
    }
diff --git a/src/Torrent.h b/src/Torrent.h
index a9943c6..ef5d75c 100644
--- a/src/Torrent.h
+++ b/src/Torrent.h
@@ -53,20 +53,105 @@ public:
    int get_bit_length() const { return bit_length; }
    void set_bit_length(int b) { bit_length=b; set_length((b+7)/8); }
    void clear() { memset(buf,0,length()); }
+   void set_range(int from,int to,bool value);
 };
 
-struct TorrentPiece
+class TorrentPiece
 {
    unsigned sources_count;	    // how many peers have the piece
+   unsigned downloader_count;	    // how many downloaders of the piece are there
+   RefToArray<const TorrentPeer*> downloader; // which peers download the blocks
+   Ref<BitField> block_map;	    // which blocks are present.
 
-   BitField block_map;		    // which blocks are present
-   xarray<const TorrentPeer*> downloader; // which peers download the blocks
+public:
+   TorrentPiece() : sources_count(0), downloader_count(0) {}
+   ~TorrentPiece() {}
+
+   unsigned get_sources_count() const { return sources_count; }
+   void add_sources_count(int diff) { sources_count+=diff; }
+   bool has_no_sources() const { return sources_count==0; }
+
+   bool has_a_downloader() const { return downloader_count>0; }
+   void set_downloader(unsigned block,const TorrentPeer *o,const TorrentPeer *n,unsigned blk_count) {
+      if(!downloader) {
+	 if(o || !n)
+	    return;
+	 downloader=new const TorrentPeer*[blk_count]();
+      }
+      const TorrentPeer*& d=downloader[block];
+      if(d==o) {
+	 d=n;
+	 downloader_count+=(n!=0)-(o!=0);
+      }
+   }
+   void cleanup() {
+      if(downloader_count==0 && downloader)
+	 downloader=0;
+   }
+   const TorrentPeer *downloader_for(unsigned block) {
+      return downloader ? downloader[block] : 0;
+   }
 
-   TorrentPiece(unsigned b)
-      : sources_count(0), block_map(b)
-      { downloader.allocate(b,0); }
+   void set_block_present(unsigned block,unsigned blk_count) {
+      if(!block_map)
+	 block_map=new BitField(blk_count);
+      block_map->set_bit(block,1);
+   }
+   void set_blocks_absent() {
+      block_map=0;
+   }
+   void free_block_map() {
+      block_map=0;
+   }
+   bool block_present(unsigned block) const {
+      return block_map && block_map->get_bit(block);
+   }
+   bool all_blocks_present(unsigned blk_count) const {
+      return block_map && block_map->has_all_set(0,blk_count);
+   }
+   bool any_blocks_present() const {
+      return block_map; // it's allocated when setting any bit
+   }
+};
+
+struct TorrentFile
+{
+   char *path;
+   off_t pos;
+   off_t length;
+   void set(const char *n,off_t p,off_t l) {
+      path=xstrdup(n);
+      pos=p;
+      length=l;
+   }
+   void unset() {
+      xfree(path); path=0;
+   }
+   bool contains_pos(off_t p) const {
+      return p>=pos && p<pos+length;
+   }
+};
 
-   bool has_a_downloader() const;
+class TorrentFiles : public xarray<TorrentFile>
+{
+   static int pos_cmp(const TorrentFile *a, const TorrentFile *b) {
+      if(a->pos < b->pos)
+	 return -1;
+      if(a->pos > b->pos)
+	 return 1;
+      // we want zero-sized files to placed before non-zero ones.
+      if(a->length != b->length)
+	 return a->length < b->length ? -1 : 1;
+      return 0;
+   }
+public:
+   TorrentFile *file(int i) { return get_non_const()+i; }
+   TorrentFiles(const BeNode *f_node,const Torrent *t);
+   ~TorrentFiles() {
+      for(int i=0; i<length(); i++)
+	 file(i)->unset();
+   }
+   TorrentFile *FindByPosition(off_t p);
 };
 
 class TorrentListener : public SMTask, protected ProtoLog, protected Networker
@@ -99,6 +184,7 @@ class Torrent : public SMTask, protected ProtoLog, public ResClient
    friend class TorrentPeer;
    friend class TorrentDispatcher;
    friend class TorrentListener;
+   friend class TorrentFiles;
    friend class DHT;
 
    bool shutting_down;
@@ -171,6 +257,7 @@ class Torrent : public SMTask, protected ProtoLog, public ResClient
    xstring info_hash;
    const xstring *pieces;
    xstring name;
+   Ref<TorrentFiles> files;
 
    Ref<DirectedBuffer> recv_translate;
    Ref<DirectedBuffer> recv_translate_utf8;
@@ -214,11 +301,32 @@ class Torrent : public SMTask, protected ProtoLog, public ResClient
    BeNode *Lookup(Ref<BeNode>& d,const char *name,BeNode::be_type_t type) { return Lookup(d->dict,name,type); }
 
    TaskRefArray<TorrentPeer> peers;
-   RefArray<TorrentPiece> piece_info;
    static int PeersCompareActivity(const SMTaskRef<TorrentPeer> *p1,const SMTaskRef<TorrentPeer> *p2);
    static int PeersCompareRecvRate(const SMTaskRef<TorrentPeer> *p1,const SMTaskRef<TorrentPeer> *p2);
    static int PeersCompareSendRate(const SMTaskRef<TorrentPeer> *p1,const SMTaskRef<TorrentPeer> *p2);
 
+   RefToArray<TorrentPiece> piece_info;
+   unsigned blocks_in_piece;
+   unsigned blocks_in_last_piece;
+   bool BlockPresent(unsigned piece,unsigned block) const {
+      return piece_info[piece].block_present(block);
+   }
+   bool AllBlocksPresent(unsigned piece) const {
+      return piece_info[piece].all_blocks_present(BlocksInPiece(piece));
+   }
+   bool AnyBlocksPresent(unsigned piece) const {
+      return piece_info[piece].any_blocks_present();
+   }
+   bool AllBlocksAbsent(unsigned piece) const {
+      return !AnyBlocksPresent(piece);
+   }
+   void SetBlocksAbsent(unsigned piece) {
+      piece_info[piece].set_blocks_absent();
+   }
+   void SetBlockPresent(unsigned piece,unsigned block) {
+      piece_info[piece].set_block_present(block,BlocksInPiece(piece));
+   }
+
    void RebuildPiecesNeeded();
    Timer pieces_needed_rebuild_timer;
    xarray<unsigned> pieces_needed;
@@ -296,6 +404,7 @@ public:
    static void ClassInit();
 
    Torrent(const char *mf,const char *cwd,const char *output_dir);
+   ~Torrent();
 
    int Do();
    int Done() const;
@@ -315,7 +424,7 @@ public:
    static void SHA1(const xstring& str,xstring& buf);
    void ValidatePiece(unsigned p);
    unsigned PieceLength(unsigned p) const { return p==total_pieces-1 ? last_piece_length : piece_length; }
-   unsigned BlocksInPiece(unsigned p) const { return (PieceLength(p)+BLOCK_SIZE-1)/BLOCK_SIZE; }
+   unsigned BlocksInPiece(unsigned p) const { return p==total_pieces-1 ? blocks_in_last_piece : blocks_in_piece; }
 
    const TaskRefArray<TorrentPeer>& GetPeers() const { return peers; }
    void AddPeer(TorrentPeer *);
@@ -772,7 +881,7 @@ public:
 
 class TorrentBlackList
 {
-   xmap<Timer*> bl;
+   xmap_p<Timer> bl;
    void check_expire();
 public:
    bool Listed(const sockaddr_u &a);
diff --git a/src/resource.cc b/src/resource.cc
index 4aa071a..e4707e7 100644
--- a/src/resource.cc
+++ b/src/resource.cc
@@ -57,13 +57,39 @@ static const char *FtpProxyValidate(xstring_c *p)
    return 0;
 }
 
+static const char *SetValidate(xstring_c& s,const char *const *set,const char *name)
+{
+   const char *const *scan;
+   for(scan=set; *scan; scan++)
+      if(s.eq(*scan))
+	 return 0;
+
+   xstring &j=xstring::get_tmp();
+   if(name)
+      j.setf(_("%s must be one of: "),name);
+   else
+      j.set(_("must be one of: "));
+   bool had_empty=false;
+   for(scan=set; *scan; scan++) {
+      if(!**scan) {
+	 had_empty=true;
+	 continue;
+      }
+      if(scan>set)
+	 j.append(", ");
+      j.append(*scan);
+   }
+   if(had_empty)
+      j.append(_(", or empty"));
+   return j;
+}
+
 static const char *FtpProxyAuthTypeValidate(xstring_c *s)
 {
-   if(s->ne("user") && s->ne("joined") && s->ne("joined-acct")
-   && s->ne("open") && s->ne("proxy-user@host"))
-      // for translator: `user', `joined', `joined-acct', `open' are literals.
-      return _("ftp:proxy-auth-type must be one of: user, joined, joined-acct, open, proxy-user@host");
-   return 0;
+   static const char *const valid_set[]={
+      "user", "joined", "joined-acct", "open", "proxy-user@host", 0
+   };
+   return SetValidate(*s,valid_set,"ftp:proxy-auth-type");
 }
 
 static const char *HttpProxyValidate(xstring_c *p)
@@ -130,6 +156,14 @@ const char *OrderValidate(xstring_c *s)
    return 0;
 }
 
+static const char *SortByValidate(xstring_c *s)
+{
+   static const char * const valid_set[]={
+      "name", "name-desc", "size", "size-desc", "date", "date-desc", 0
+   };
+   return SetValidate(*s,valid_set,"mirror:order-by");
+}
+
 #if USE_SSL
 static
 const char *AuthArgValidate(xstring_c *s)
@@ -137,30 +171,21 @@ const char *AuthArgValidate(xstring_c *s)
    for(char *i=s->get_non_const(); *i; i++)
       *i=to_ascii_upper(*i);
 
-   if(strcmp(*s,"SSL")
-   && strcmp(*s,"TLS")
-   && strcmp(*s,"TLS-P")
-   && strcmp(*s,"TLS-C"))
-      return _("ftp:ssl-auth must be one of: SSL, TLS, TLS-P, TLS-C");
-
-   return 0;
+   const char *const valid_set[]={
+      "SSL", "TLS", "TLS-P", "TLS-C", 0
+   };
+   return SetValidate(*s,valid_set,"ftp:ssl-auth");
 }
 static
 const char *ProtValidate(xstring_c *s)
 {
-   if(!**s)
-      return 0;
-
    for(char *i=s->get_non_const(); *i; i++)
       *i=to_ascii_upper(*i);
 
-   if(strcmp(*s,"P")
-   && strcmp(*s,"C")
-   && strcmp(*s,"S")
-   && strcmp(*s,"E"))
-      return _("must be one of: C, S, E, P, or empty");
-
-   return 0;
+   const char *const valid_set[]={
+      "C", "S", "E", "P", "", 0
+   };
+   return SetValidate(*s,valid_set,"ftps:initial-prot");
 }
 #endif
 
@@ -300,6 +325,7 @@ static ResType lftp_vars[] = {
    {"net:connection-limit",	 "0",	  ResMgr::UNumberValidate,0},
    {"net:connection-takeover",	 "yes",   ResMgr::BoolValidate,0},
 
+   {"mirror:sort-by",		 "name",  SortByValidate,ResMgr::NoClosure},
    {"mirror:order",		 "*.sfv *.sig *.md5* *.sum * */", 0,ResMgr::NoClosure},
    {"mirror:parallel-directories", "yes", ResMgr::BoolValidate,ResMgr::NoClosure},
    {"mirror:parallel-transfer-count", "1",ResMgr::UNumberValidate,ResMgr::NoClosure},
diff --git a/src/xmap.cc b/src/xmap.cc
index 4bc9a86..2276bce 100644
--- a/src/xmap.cc
+++ b/src/xmap.cc
@@ -136,6 +136,7 @@ void _xmap::_remove(entry **ep)
    if(!ep || !*ep)
       return;
    entry *e=*ep;
+   e->key.unset();
    *ep=e->next;
    xfree(e);
    entry_count--;
diff --git a/src/xstring.h b/src/xstring.h
index 264baf6..4a284ee 100644
--- a/src/xstring.h
+++ b/src/xstring.h
@@ -222,7 +222,8 @@ public:
    static xstring& cat(const char *first,...) ATTRIBUTE_SENTINEL;
    static xstring& join(const char *sep,int n,...);
 
-   void truncate(size_t n=0);
+   void truncate() { set_length(0); }
+   void truncate(size_t n);
    void truncate_at(char c);
    /* set_length can be used to extend the string, e.g. after modification
       with get_space+get_non_const. */