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¶
- 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 "Xmodem::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
