numinterval

#!/usr/bin/perl -w

# interval: This program calculates and displays the intervals between the
# first line and the second, between the second line and the third on
# through the end of the file.
#   
# Copyright (C) 2002-2004 Suso Banderas

# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
#
# You may contact the author at <suso@suso.org>.

#######################
# VARIABLES AND SETUP #
#######################

use Getopt::Std;
use strict;
use vars qw/ %opts $verbose /;

getopts('hdVq', \%opts);

my ($file, @number_array,$interval, $number);

if ($opts{'h'}) {
    &help();
    exit(0);
}

if ($opts{'d'}) {
    $verbose = 3;
    print STDERR "Debug mode\n";
} elsif ($opts{'V'}) {
    $verbose = 2;
    print STDERR "Verbose mode\n";
} elsif ($opts{'q'}) {
    $verbose = 0;  # Nothing except the final answer
} else {
    $verbose = 1;  # Normal warnings and such.
}


################
# MAIN PROGRAM #
################

# For file args
if (@ARGV) {
    foreach $file (@ARGV) {
        print STDERR "Reading from file $file.\n" if ($verbose >= 2);
        open (ARGFILE, "$file") &&
         process_filehandle(\*ARGFILE, \@number_array) ||
        $verbose && warn "Couldn't open file $file for reading: $!\n";
        close (ARGFILE);
    }
# For STDIN
} else {
    print STDERR "Reading from STDIN.\n" if ($verbose >= 2);
    process_filehandle(\*STDIN, \@number_array);
}

my $lastnumber;
foreach $number (@number_array) {
    if ($lastnumber) {
        $interval = $number - $lastnumber;
        print "$interval\n"; 
    }        
    $lastnumber = $number;
}

exit(0);

###############
# SUBROUTINES #
###############

sub help {
	print <<"EOF";
-----------------------------------------------------------------------
interval : Calculate the numeric intervals between lines in input.
-----------------------------------------------------------------------
Usage:

    template [options] <file>
    | template [options]
    template [options]

Options:
        -q      Don't print any warnings.
        -d      Debug. For developers only.
        -V      Increase verbosity.
        -h      Help: You're looking at it.
EOF
}

sub process_filehandle {
    my $filehandle = shift;
    my $number_array_ref = shift;

    while (<$filehandle>) {
        if (m/^\s*(\-?[0-9]*\.?[0-9]+)/) {
            print STDERR "found number: $1\n" if ($verbose >= 3);
            push(@$number_array_ref, $1);
        }
    }
    return 1;
}


# Lay down some of that perl pod action.
=pod

=head1 NAME

interval - Show the numeric intervals between each line in a file.

=head1 SYNOPSIS

B<interval> [-dhV] <FILE>

| B<interval> [-dhV]    (Input on STDIN from pipeline.)

B<interval> [-dhV]      (Input on STDIN.  Use Ctrl-D to stop.)

=head1 DESCRIPTION

B<inter> is a program that is part of the numeric utilities package.  B<interval>
will calculate and display the numeric interval between one number and the
next on an input stream.

This can be quite useful for showing quantities of increase or decrease 
of data when the numbers themselves aren't providing you with what you want.
For instance, I wrote this program after wanting to see the rate of change
in box office ticket sales for movies on imdb.com. ;-)

=head1 OPTIONS

    -h  Help: You're looking at it.
    -V  Increase verbosity.
    -d  Debug mode.  For developers
    -q  Don't print any warnings.  Quiet mode.


=head1 SEE ALSO

average(1), bound(1), normalize(1), numgrep(1), numprocess(1), numsum(1), random(1), range(1), round(1)

=head1 COPYRIGHT

interval is part of the num-utils package, which is copyrighted by
Suso Banderas and released under the GPL license.  Please read
the COPYING and LICENSE files that came with the num-utils package

  Developers can read the GOALS file and contact me about providing
submissions or help for the project.

=head1 MORE INFO

More info on template can be found at:

=over 1

=item B<http://suso.suso.org/programs/num-utils/>

=back

=cut