# Create next/prev links 
 $default_sort = ""; 
 if (-e "$boardsdir/$currentboard.opt" ) { require "$boardsdir/$currentboard.opt"; } 
 fopen(LISTS, "$boardsdir/$INFO{'board'}.txt"); 
 @boardtopics = <LISTS>; 
 $threadcount = $#boardtopics + 1; 
 fclose(LISTS); 
 
 # Sort list 
 if ($default_sort ne "") { 
  @tmplist = @boardtopics; 
  $date2 = $date; 
  for($i=0;$i<$threadcount;$i++) { 
   ($mnum, $msub, $mname, $dummy, $mdate, $mreplies, $dummy) = split( /\|/, $boardtopics[$i], 7 ); 
   if ($default_sort eq "subject") { $tmplist[$i] = $msub."|".$boardtopics[$i]; } 
   elsif ($default_sort eq "created") { 
    fopen(FILE, "$datadir/$mnum.txt"); 
    $tmpa = <FILE>; 
    fclose(FILE); 
    ($dummy, $dummy, $dummy, $date1, $dummy) = split(/\|/, $tmpa, 5); 
    &calcdifference; 
    $tmplist[$i] = $result."|".$boardtopics[$i]; 
   } 
   elsif ($default_sort eq "author") { $tmplist[$i] = $mname."|".$boardtopics[$i]; } 
   elsif ($default_sort eq "last") { 
    $date1 = $mdate; 
    &calcdifference; 
    $tmplist[$i] = $result."|".$boardtopics[$i]; 
   } 
   elsif ($default_sort eq "replies") { $tmplist[$i] = $mreplies."|".$boardtopics[$i]; } 
   elsif ($default_sort eq "views") {  
    if( -e "$datadir/$mnum.data" ) { 
     fopen(FILE, "$datadir/$mnum.data"); 
     $tmpa = <FILE>; 
     fclose(FILE); 
     ($views, $dummy) = split(/\|/, $tmpa, 2); 
     $views = $views ? $views - 1 : 0; 
    } else { $views = "0"; } 
    $tmplist[$i] = $views."|".$boardtopics[$i];  
   } 
   elsif ($default_sort eq "rating") {  
    if( -e "$datadir/$mnum.data" ) { 
     fopen(FILE, "$datadir/$mnum.data"); 
     $tmpa = <FILE>; 
     fclose(FILE); 
     ($dummy, $dummy, $rate, $dummy) = split( /\|/, $tmpa, 4 ); 
     if ($rate eq "") { $rate = "0"; } 
    } else { $rate = "0"; } 
    $tmplist[$i] = $rate."|".$boardtopics[$i];  
   } 
  } 
  if ($default_sort eq "subject" || $default_sort eq "author") { @sortlist = sort{uc($a) cmp uc($b)} (@tmplist); } 
  elsif ($default_sort eq "created" || $default_sort eq "last") { @sortlist = sort{$a<=>$b} (@tmplist); } 
  else { @sortlist = sort{$b<=>$a} (@tmplist); } 
  for($i=0;$i<$threadcount;$i++) { 
   ($dummy, $tmplist[$i]) = split(/\|/, $sortlist[$i], 2); 
   $boardtopics[$i] = $tmplist[$i]."\n"; 
  } 
  chomp(@boardtopics); 
 } 
 
	################################
### START PREVIOUS/NEXT PLUS ###
@threads = @boardtopics;

$thisthreadpos = -1;
$numthreads = @threads;
#work out where this thread is in the list
for ($i = 0; $i < $numthreads; $i++)
{
	if ($threads[$i] =~ /^$viewnum/) { $thisthreadpos = $i; }
}

($junk, $curtitle) = split(/\|/, $threads[$thisthreadpos]);

#do we have a previous or next thread to link to?
$previouspos = ($thisthreadpos - 1 >= 0) ? $thisthreadpos - 1 : -1;
$nextpos = ($thisthreadpos + 1 < $numthreads) ? $thisthreadpos + 1 : -1;

#construct previous link
if ($previouspos >= 0)
{
	($previd, $prevtitle, $junk, $junk, $prevdate) = split(/\|/, $threads[$previouspos]);

	#should we abbreviate the thread title?
	if (length($prevtitle) > 20) { $prevtitle = substr($prevtitle, 0, 20) . '...'; }

	#make sure the link goes to the last page of the thread display
	fopen(FILE, "$datadir/$previd.txt"); @num_posts = <FILE>; fclose(FILE);
	$num_posts = @num_posts; $num_posts--;

	#is the previous thread unread?
	$dlp = &getlog($previd); $threaddate = stringtotime($prevdate);
	$prevnew = ( $max_log_days_old && $dlp < $threaddate && $username ne 'Guest' && &getlog("$INFO{'board'}--mark") < $threaddate ) ? 'previous_new' : 'previous';
	$previouslink = qq~<a href="$cgi;action=display;num=$previd;start=$num_posts"><img src="$imagesdir/$prevnew.gif" border=0 alt="$txt{'768'}: $prevtitle">&nbsp;&nbsp;$prevtitle</a>&nbsp;&nbsp;&laquo;-&nbsp;~;
}
else { $previouslink = ''; }

#construct next link
if ($nextpos > 0)
{
	($nextid, $nexttitle, $junk, $junk, $nextdate) = split(/\|/, $threads[$nextpos]);

	#should we abbreviate the thread title?
	if (length($nexttitle) > 15) { $nexttitle = substr($nexttitle, 0, 20) . '...'; }

	#make sure the link goes to the last page of the thread display
	fopen(FILE, "$datadir/$nextid.txt"); @num_posts = <FILE>; fclose(FILE);
	$num_posts = @num_posts; $num_posts--;
	
	#is the next thread unread?
	$dlp = &getlog($nextid); $threaddate = stringtotime($nextdate);
	$nextnew = ( $max_log_days_old && $dlp < $threaddate && $username ne 'Guest' && &getlog("$INFO{'board'}--mark") < $threaddate ) ? 'next_new' : 'next';
	$nextlink = qq~&nbsp;-&raquo;&nbsp;&nbsp;<a href="$cgi;action=display;num=$nextid;start=$num_posts">$nexttitle&nbsp;&nbsp;<img src="$imagesdir/$nextnew.gif" border=0 alt="$txt{'767'}: $nexttitle"></a>~;
}
else { $nextlink = ''; }

$nav = '';
$nav = qq~$previouslink&nbsp;<a href="$cgi;action=post;title=$txt{'464'}">$txt{'33'}</a>&nbsp;$nextlink~;
### END PREVIOUS/NEXT PLUS #####
################################