# TimeChk.pm: Time Check Routines

package RDA::Extern::TimeChk;

# $Id: TimeChk.pm,v 1.6 2013/11/22 11:34:59 RDA Exp $
# ARCS: $Header: /home/cvs/cvs/RDA_8/src/scripting/lib/RDA/Extern/TimeChk.pm,v 1.6 2013/11/22 11:34:59 RDA Exp $
#
# Change History
# 20131103  MSC  Make code more strict.

=head1 NAME

RDA::Extern::TimeChk - Time Check Routines

=head1 SYNOPSIS

 require RDA::Extern::TimeChk;

=head1 DESCRIPTION

The following method is available:

=cut

use strict;

BEGIN
{ use Exporter;
}

# Define the global public variables
use vars qw($VERSION @ISA);
$VERSION = sprintf('%d.%02d', q$Revision: 1.6 $ =~ /(\d+)\.(\d+)/);
@ISA     = qw(Exporter);

# Report the package version
sub Version
{ return $VERSION;
}

=head2 S<RDA::Extern::TimeChk::check_clock($ctx[,$cnt])>

This method checks for monotonically increasing time. You can specify the
number of clock checks as an argument. It does 1000000 tests by default. It
returns an empty string on successful completion, or otherwise, an error
message.

=cut

sub check_clock
{ my ($ctx, $cnt) = @_;
  my ($cur, $prv);

  eval 'require Time::HiRes';
  return "Not available: $@" if $@;

  $cnt = 1000000 unless defined($cnt);
  $prv = [Time::HiRes::gettimeofday()];
  for (1..$cnt)
  { $cur = [Time::HiRes::gettimeofday()];
    return sprintf('Time went backwards: %d.%06d -> %d.%06d', @{$prv}, @{$cur})
      if Time::HiRes::tv_interval($prv, $cur) < 0;
    $prv = $cur;
  }
  return q{};
}

1;

=head1 COPYRIGHT NOTICE

Copyright (c) 2002, 2016, Oracle and/or its affiliates. All rights reserved.

=head1 TRADEMARK NOTICE

Oracle and Java are registered trademarks of Oracle and/or its
affiliates. Other names may be trademarks of their respective owners.

=cut