#!/usr/bin/perl -w
#
# fetchRunningTotal
# Michael Han, (c) 8/2002
# Documentation and contact info at http://www.mikehan.com/cricket/
# $Id: fetchRunningTotal,v 1.1 2002/08/15 08:19:22 mikehan Exp $
# 
# Fetch a sequence of OIDs and return the running sums of each all prior values
# For example, fetchRunningTotal is invoked with three OIDs which have the
# respective values "6.2" "9.3" and "84.5". The output of fetchRunningTotal is:
# 6.2
# 15.5
# 100
# fetchRunningTotal is intended to be called as an EXEC ds within Cricket
#
my $usage="
Usage:
$0 ( snmpUtils snmp target ) ( OID ) [ [[op] OID] ... ]
    op  +,-,*,/,** (addition assumed if omitted)
e.g. $0 public\@localhost:1161 1.3.6.1.4.1.2021.11.53 + 1.3.6.1.4.1.2021.11.50
";

BEGIN {
	$main::gInstallRoot = (($0 =~ m:^(.*/):)[0] || "./") . "..";
}

use strict;
use lib "$main::gInstallRoot/lib";

use snmpUtils;

if ( scalar @ARGV < 2 ) {
	print $usage;
	exit 2;
}

my $snmp = shift;

my @oid;
my @op;
my( $oid, $op, $i );
while ( $i = shift ) {
	if ( $i eq '+' || $i eq '-' || $i eq '*' || $i eq '/' || $i eq '**' ) {
		$op = $i;
		$oid = shift or &usage;
		&add_oid( $oid, $op );
	} else {
		&add_oid( $i, '+' );
	}
}

my @value = snmpUtils::get( $snmp, @oid );

my @total;
for ( $i = 0; $i < scalar @value; $i++ ) {
	for ( my $j = 0; $j <= $i; $j++ ) {
		if ( $op[$j] eq "+" ) {
			$total[$i] += $value[$j];
		} elsif ( $op[$j] eq "-" ) {
			$total[$i] -= $value[$j];
		} elsif ( $op[$j] eq "*" ) {
			$total[$i] *= $value[$j];
		} elsif ( $op[$j] eq "/" ) {
			$total[$i] /= $value[$j];
		} elsif ( $op[$j] eq "**" ) {
			$total[$i] **= $value[$j];
		} else {
			# Shouldn't be possible
			print "$op[$j] not a sensible operator!\n";
			exit 1;
		}
	}
	print "$total[$i]\n";
}

sub usage {
	print $usage;
	exit 1;
}

sub add_oid {
	$oid = shift;
	$op = shift;

	if ( ! $oid =~ m/^\.?((\d)+\.)+\d$/ ) {
		print "$oid: does not appear to be a valid numeric OID\n";
		exit 1;
	}
	push @oid, $oid;
	push @op, $op;
}