#!/usr/bin/perl
# cleanup of data files
$version="1.2"; $date="21 Nov 2008"; #  by Nick Manini

sub print_help {
    print STDERR <<EOF;
prunedata: cleunup pointlessly long data files

SYNTAX:  prunedata [-t threshold] datafile
-t      : change the rejection threshold from the default = $SMALL
	  [a higher threshold results in less points being kept]
-h      : print this help
EOF
return;
}


$BIG=1.e30;
$SMALL=1.e-5;
$TINY=1.e-16;

$xkeep=$BIG;
$ykeep=$BIG;

$thresh=$SMALL;


while($p=shift(@ARGV)){
# [ file ] check existence of 'file'
    if($p=~/^[^\-]/){
        if(!(-e  $p)){
            die "file $p cannot be accessed\n";
        }
        push (@FILELIST,$p);
        next;
    }
    if($p eq "-t"){ # change threshold from default
        $thresh=shift(@ARGV)+0;
	$thresh>0 or die "there is no point setting a threshold <=0\n";
        next;
    }
    if($p eq "-h"){ # print help
        print_help;
        exit;
    }
    print STDERR "Error: invalid option $p\n ";
    print_help;
    exit;
}


if ($#FILELIST==-1)
{
    push(@FILELIST,"-");    #       adds stdio for lack of arguments
}


while ($filename=shift(@FILELIST)){	# loop on filenames
    open(INF, $filename);       #       Open for input

    while (<INF>){		# loop on lines in the file
	s/^\s+//;
	@data=split(/[()\s]+/);

	$x=$data[0]+0;
	$y=$data[1]+0;

#	print $x," ",$y,"\n";
	if(abs($data[0]-$xkeep)/(abs($xkeep)+$TINY) > $thresh &&
	   abs($data[1]-$ykeep)/(abs($ykeep)+$TINY) > $thresh){
	    print;
	    $xkeep=$x;
	    $ykeep=$y;
	}
    }
    close(INF);
}