#!/usr/bin/perl -w
#
# Quick 'n' dirty plotting of the free.csv report.

use strict;
use English;

BEGIN {
  # Argument processing.
  if (@ARGV == 2 and $ARGV[1] =~ /\D/) {
    # free_plot.pl 123 file.csv
    # Yuck, because the 'missing' value could be either top limit.
    die "Arguments '@ARGV' too hard to interpret:  use 'NNN NNN file.c
+sv'\n"

  } elsif (@ARGV == 1 and $ARGV[0] =~ /\D/) {
    # free_plot.pl file.csv
    # Stick in a couple of empty strings to get the TOP_* constants to
+ work.
    unshift @ARGV, '','';
  }
}

my $screen;            # screen control panel

use constant TERM_SIZE => 75;    # how big is the screen?
use constant TIME_FLD  =>  6;      # how wide is the time display?
use constant TOP_LOAD => shift || 20;        # scale factor for load a
+verage
use constant TOP_BUFF => shift || 20000;    # scale factor for buffer 
+size

INIT {
  {
    no warnings;
    require Term::Screen;
  }

  # Set up the screen.
  $screen = Term::Screen->new() or die "Something's wrong with Term::S
+creen";
  $screen->clrscr();
  $screen->at(0,TIME_FLD)->puts(join('',
                     '|----' x (TERM_SIZE/5),
                     '*/L' . TOP_LOAD,
                     ' o/F+/B' . TOP_BUFF,
                    ) );
}

END {
  # Cleanup.
  $screen->at($screen->{ROWS}-1, 0);
}

$|++;                # no buffered output

# Ctrl-C handler.
$SIG{INT} = sub { exit };

# Do we have a filename to read?
if (my $file = shift) {
  open(INPUT, $file) or die $!;
} else {
  open(INPUT, "<&STDIN") or die $!;
}

while (<INPUT>) {        # process all the input

                # CSV file has 'time,loadavg,junk,buff,...'
  my($time,$load,$buff,$free) = (split /,/)[0,1,3,10];
  next if ($load . $buff . $free) =~ /[^\d\.]/;

  $screen->at(1,0)->il;        # new line after the axis

  $time =~ s/\D//g;        # reduce time to HHMMSS
  $time =~ s/.*(\d{6})$/$1/;
  $screen->at(1,0)->puts($time);

  $_ ||= 0E0              # for old format CSV with missing fields
    foreach ($load,$buff,$free);

                # create scaling
  my $load_sp = min(TERM_SIZE, TERM_SIZE * ($load/TOP_LOAD));
  my $buff_sp = min(TERM_SIZE, TERM_SIZE * ($buff/TOP_BUFF));
  my $free_sp = min(TERM_SIZE, TERM_SIZE * ($free/TOP_BUFF));

  if ($load_sp == $buff_sp) {
    # The overlap case.
    $screen->at(1,TIME_FLD+$load_sp)->puts('X');
  } else {
    # The normal case.
    $screen->at(1,TIME_FLD+$load_sp)->puts('*');
    if ($buff_sp == $free_sp) {
      $screen->at(1,TIME_FLD+$buff_sp)->puts('x');
    } else {
      $screen->at(1,TIME_FLD+$buff_sp)->puts('+');
      $screen->at(1,TIME_FLD+$free_sp)->puts('o');
    }
  }
}

sub min {
  my @list = grep(defined,@_);
  return $list[0] unless @list > 1;
  return (sort {$a <=> $b} @list)[0];
}
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