From b458fc8c6267d391e4664f87d796c998212dbe32 Mon Sep 17 00:00:00 2001
From: Marcello Sega <sega@roma2.infn.it>
Date: Tue, 29 Apr 2014 17:26:39 +0200
Subject: [PATCH] fixes VMD crash with long lines in vtf files

---
 scripts/vtf.tcl | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/scripts/vtf.tcl b/scripts/vtf.tcl
index 2030da82e1..870fae0c94 100644
--- a/scripts/vtf.tcl
+++ b/scripts/vtf.tcl
@@ -195,8 +195,20 @@ proc writevsf { file args } {
             lappend aids "$from:$to"
         }
         unset from
-        
-        puts $file "atom [join $aids ,] $desc"
+        # let's group atom ranges, so that there are no more than 8 per line
+        # This fixes a problem with the vmd plugin, and makes the vtf more 
+        # readable anyway.
+        set start 0
+        set maxlen 8
+        set ll  [llength [lrange $aids $start end ]]
+        while { $ll >= $maxlen } {
+              puts $file "atom [join [lrange $aids $start [expr $start + $maxlen -1]] ,] $desc"
+              incr start $maxlen
+              set ll  [llength [lrange $aids $start end ]]
+        }
+        if { $start < [llength $aids ] } { 
+          puts $file "atom [join [lrange $aids  $start  end] ,] $desc"
+        }
     }
     
     # Print bond data