Device::Modem::Protocol::Xmodem(3pm)			User Contributed Perl Documentation		      Device::Modem::Protocol::Xmodem(3pm)

NAME

       Device::Modem::Protocol::Xmodem

Xmodem::Block
       Class that represents a single Xmodem data block.

       Synopsis

	       my $b = Xmodem::Block->new( 1, 'My Data...<until-128-chars>...' );
	       if( defined $b ) {
		       # Ok, block instanced, verify its checksum
		       if( $b->verify( 'checksum', <my_chksum> ) ) {
			       ...
		       } else {
			       ...
		       }
	       } else {
		       # No block
	       }

	       # Calculate checksum, crc16, 32, ...
	       $crc16 = $b->crc16();
	       $crc32 = $b->crc32();
	       $chksm = $b->checksum();

Xmodem::Buffer
       Class that implements an Xmodem receive buffer of data blocks. Every block of data is represented by a "Xmodem::Block" object.

       Blocks can be pushed and popped from the buffer. You can retrieve the last block, or the list of blocks from buffer.

       Synopsis

	       my $buf = Xmodem::Buffer->new();
	       my $b1  = Xmodem::Block->new(1, 'Data...');

	       $buf->push($b1);

	       my $b2  = Xmodem::Block->new(2, 'More data...');
	       $buf->push($b2);

	       my $last_block = $buf->last();

	       print 'now I have ', scalar($buf->blocks()), ' in the buffer';

	       # TODO document replace() function ???

Xmodem::Constants
       Package that contains all useful Xmodem protocol constants used in handshaking and data blocks encoding procedures

       Synopsis

	       Xmodem::Constants::soh ........... 'start of header'
	       Xmodem::Constants::eot ........... 'end of trasmission'
	       Xmodem::Constants::ack ........... 'acknowlegded'
	       Xmodem::Constants::nak ........... 'not acknowledged'
	       Xmodem::Constants::can ........... 'cancel'
	       Xmodem::Constants::C   ........... `C' ASCII char

	       Xmodem::Constants::XMODEM ........ basic xmodem protocol
	       Xmodem::Constants::XMODEM_1K ..... xmodem protocol with 1k blocks
	       Xmodem::Constants::XMODEM_CRC .... xmodem protocol with CRC checks

	       Xmodem::Constants::CHECKSUM ...... type of block checksum
	       Xmodem::Constants::CRC16 ......... type of block crc16
	       Xmodem::Constants::CRC32 ......... type of block crc32

Xmodem::Receiver
       Control class to initiate and complete a "X-modem" file transfer in receive mode

       Synopsis

	       my $recv = Xmodem::Receiver->new(
		       modem	=> {Device::Modem object},
		       filename => 'name of file',
		       XXX protocol => 'xmodem' | 'xmodem-crc', | 'xmodem-1k'
	       );

	       $recv->run();

       Object methods

       abort_transfer()
	   Sends a cancel char ("can"), that signals to sender that transfer is aborted. This is issued if we receive a bad block number, which
	   usually means we got a bad line.

       modem()
	   Returns the underlying Device::Modem object.

       receive_message()
	   Retreives message from modem and if a block is detected it breaks it into appropriate parts.

       run()
	   Starts a new transfer until file receive is complete. The only parameter accepted is the (optional) local filename to be written.

       send_ack()
	   Sends an acknowledge ("ack") char, to signal that we received and stored a correct block Resets count of timeouts and returns the "Xmo-
	   dem::Block" object of the data block received.

       send_timeout()
	   Sends a timeout ("nak") char, to signal that we received a bad block header (either a bad start char or a bad block number), or a bad
	   data checksum. Increments count of timeouts and at ten timeouts, aborts transfer.

       See also

       - Device::Modem

perl v5.8.8							    2005-04-30				      Device::Modem::Protocol::Xmodem(3pm)