--- /home/martin/bin/parallel	2015-06-26 14:31:03.696914185 +0900
+++ parallel-mcf	2015-06-26 15:30:16.422813477 +0900
@@ -318,7 +318,9 @@
     my $header = find_header(\$buf,$in);
     while(1) {
       my $anything_written = 0;
-      if(not read($in,substr($buf,length $buf,0),$blocksize)) {
+      my $buflen = length $buf;
+      my $readsize = ($blocksize > $buflen) ? $blocksize-$buflen : $blocksize;
+      if(not read($in,substr($buf,$buflen,0),$readsize)) {
 	  # End-of-file
 	  $chunk_number != 1 and last;
 	  # Force the while-loop once if everything was read by header reading