[Alistair.McGlinchy@xxxxxxxxxxxxxxxxxxxxx]

Justin,

> > > 1)  I have a 2GB capture file that I need to split.  I don't 
[...]
> Again, editcap only gives a single segment.  It does not 
> break up the file into many arbitrary-sized or -length 
> chunks.  See 'man split' for a text version of what I'm talking about.

I understand your requirement and it sounds like a great utility. Many a
time I've been stuck in a testbed with a large trace file and a stack of
floppies, and I spend far too much time fluffing about with WinZip.  Short
of adding new features to editcap.c (which isn't too insurmountable a task
if you know c), I can suggest that you make better use of editcap. 

This version of the split utility will mean that your big trace file will
only need to be read log2(n) times rather than log2(n) times. You'll need to
tweak the "copy" to "cp" if your lucky enough to use a real operating
system. :-)

use strict;
my $orig_file =               $ARGV[0] || "bigfile.dmp";
my $required_frames_per_file= $ARGV[1] || 2**16; 
# At (say) 100 bytes per frame a 2GB file will have 20e6 frames < 2**25 
my $max_frame=                 $ARGV[2] || 2**25;

sub split_efficient {
	my ($file_name, $frame_count,$delete_orig)=@_;
	return if $required_frames_per_file > $frame_count;

	# (ActivePerl has a bug with files > 2**31 so I need to check a
lower limit too)
	return if (-s $file_name < 50 and -s $file_name >= 0);

	my $cmd;
	my $mid_frame= int($frame_count/2);
	$cmd="editcap -r $file_name $file_name.1
".($mid_frame+1)."-$frame_count";
	`$cmd`;
	
	if ((-s "$file_name.1" < 50) and (-s "$file_name.1">0)) {
		# There's no data in this second file
		unlink "$file_name.1";
		if ($delete_orig) {
			rename 	$file_name, "$file_name.0"
		} else {
			`copy $file_name $file_name.0`;
		}
	} else {
		$cmd="editcap -r $file_name $file_name.0 1-$mid_frame";
		`$cmd`;
		unlink $file_name;
	}	
	split_efficient("$file_name.0",$mid_frame,1) ;
	split_efficient("$file_name.1",$mid_frame,1) ;
}

split_efficient($orig_file,$max_frame,0);

# Rename all those binary suffixes back into decimal.
my ($orig_prefix,$orig_suffix) = ($orig_file =~/^(.*)\.([^\.]*)$/);
for (<*.*>) {
	next unless /$orig_file((?:\.[01])+)+$/;
	my $old=$_;
	(my $suffix=$1)=~ s#\.##g;
	my $new_file="$orig_prefix.".eval("0b$suffix").".$orig_suffix";
	rename $old, $new_file;
}


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