Device::Modem::Protocol::Xmodem (3pm)

Class that represents a single Xmodem data block.

\$1

        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();

Class that implements an Xmodem receive buffer of data blocks. Every block of data is represented by a \*(C`Xmodem::Block\*(C' object.

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

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

Control class to initiate and complete a \*(C`X-modem\*(C' file transfer in receive mode my $recv = Xmodem::Receiver->new( modem => {Device::Modem object}, filename => 'name of file', XXX protocol => 'xmodem' | 'xmodem-crc', | 'xmodem-1k' );

$recv->run();

abort_transfer()

Sends a cancel char (\*(C`can\*(C'), 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 (\*(C`ack\*(C') char, to signal that we received and stored a correct block Resets count of timeouts and returns the \*(C`Xmodem::Block\*(C' object of the data block received.

send_timeout()

Sends a timeout (\*(C`nak\*(C') 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.

- Device::Modem