# Serial.pm
# John Simpson <jms1@jms1.net> 2005-08-01
#
# Serial port control functions specific to dealing with Alinco DJ-296
#
###############################################################################
#
# Copyright (C) 2005 John Simpson.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License, version 2, as
# published by the Free Software Foundation.
#
# 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
# or visit http://www.gnu.org/licenses/gpl.txt
#
###############################################################################

package Serial ;
require 5.003 ;
use strict ;
use Carp ;

###############################################################################
#
# configuration and globals

use vars qw ( $port ) ;

BEGIN
{
	use Exporter ;
	use vars qw ( $VERSION @ISA @EXPORT @EXPORT_OK ) ;

	$VERSION	= 1.0 ;
	@ISA		= qw ( Exporter ) ;
	@EXPORT		= qw ( openport closeport sendline recvline ) ;
	@EXPORT_OK	= qw ( ) ;

	$port		= undef ;
}

###############################################################################
#
# open and close the port, using a given filename

sub openport($)
{
	open ( $port , "+<" , $_[0] )
		or confess "Can\'t open $_[0] for input/output: $!\n" ;
}

sub closeport()
{
	if ( $port )
	{
		close ( $port ) ;
		$port = undef ;
	}
}

###############################################################################
#
# send a line of text to the port. line ends with CR

sub sendline($)
{
	confess "Called sendline() without openport()\n" unless ( $port ) ;

	my $text = shift ;
	chomp $text ;

	syswrite ( $port , "$text\r" ) ;
}

###############################################################################
#
# receive a line of text from the port. ends with LF. strip CR and NUL.

sub recvline()
{
	confess "Called recvline() without openport()\n" unless ( $port ) ;

	my $line = "" ;
	my $c    = "" ;

	while ( my $z = sysread ( $port , $c , 1 ) )
	{
		next if ( $c eq "\0" ) ;
		next if ( $c eq "\r" ) ;

		$line .= $c ;
		last if ( "\n" eq $c ) ;
	}

	chomp $line ;
	return $line ;
}

###############################################################################
#
# make sure we can run

1 ;