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

NAME

Device::Modem::Protocol::Xmodem - XModem protocol implementation

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

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.
Returns the underlying Device::Modem object.
Retrieves message from modem and if a block is detected it breaks it into appropriate parts.
Starts a new transfer until file receive is complete. The only parameter accepted is the (optional) local filename to be written.
Sends an acknowledge ("ack") char, to signal that we received and stored a correct block Resets count of timeouts and returns the "Xmodem::Block" object of the data block received.
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

2020-06-20 perl v5.30.3