Detailed Description

Check and remove FCS from each incoming frame ("KERMIT" variant).

See also: crc16_checksum.h, crc16::KermitTx.

Definition at line 56 of file crc16_checksum.h.

#include <crc16_checksum.h>

Inheritance diagram for satcat5::crc16::KermitRx:

Collaboration diagram for satcat5::crc16::KermitRx:

Public Member Functions
	KermitRx (satcat5::io::Writeable *dst, u16 init=0, u16 xorout=0)

bool	write_finalize () override
	Mark end of frame and release temporary working data. More...

void	error_incr ()
	Increment the internal error counter. More...

void	error_incr (unsigned incr)

unsigned	get_write_space () const override
	How many bytes can be written without blocking? More...

void	write_abort () override
	If possible, abort the current partially-written packet. More...

unsigned	byte_count (bool reset=true) override
	Bytes transferred since the last query.

unsigned	frame_count (bool reset=true) override
	Frames transferred since the last query.

unsigned	error_count (bool reset=true) override
	(Optional) Error events since the last query.

void	byte_incr (unsigned incr)
	Increment any of the internal counters.

void	frame_incr (unsigned incr)

void	write_u8 (u8 data)
	One of many functions for writing integer/floating point values, see details. More...

virtual void	write_bytes (unsigned nbytes, const void *src)
	Write 0 or more bytes from a buffer. More...

void	write_str (const char *str)
	Write the contents of a null-terminated string. More...

template<class T >
void	write_obj (const T &obj)
	Templated wrapper for any object with the following method: `void write_to(satcat5::io::Writeable* wr) const;`

Protected Member Functions
void	chk_reset () override
	Reset checksum calculation to its initial state.

bool	sreg_match (u16 fcs)
	Child class MUST call sreg_match(...) during write_finalize(). More...

bool	sreg_push (u8 &data)
	Child class MUST call sreg_push(...) during write_next(). More...

virtual void	write_overflow ()
	Optional error handling for write overflow. More...

Protected Attributes
u16	m_chk
	Checksum state.

const u16	m_init
	State after reset.

u16	m_sreg
	Big-endian input buffer.

satcat5::io::Writeable *const	m_dst
	Output object.

unsigned	m_byte_ct
	Cumulative byte count.

unsigned	m_err_ct
	Cumulative error count.

unsigned	m_frm_ct
	Cumulative frame count.

unsigned	m_frm_len
	Length of current frame.

friend	LimitedWrite

friend	WriteableBroadcast

friend	WriteableRedirect

Private Member Functions
void	write_next (u8 data) override
	Write the next byte to the underlying buffer or device. More...

Private Attributes
const u16	m_xorout

Member Function Documentation

◆ error_incr()

void satcat5::io::ChecksumRxCommon::error_incr ( )

inlineinherited

Increment the internal error counter.

Some systems use the checksum error counter to consolidate tracking of multiple frame-error types.

See also: ccsds_aos.h.

Definition at line 118 of file io_checksum.h.

◆ get_write_space()

unsigned ChecksumRxCommon::get_write_space ( ) const

overridevirtualinherited

How many bytes can be written without blocking?

Child objects of io::Writeable MUST override this method.

Implements satcat5::io::Writeable.

Definition at line 38 of file io_checksum.cc.

◆ sreg_match()

bool satcat5::io::ChecksumRx< u16 , N >::sreg_match ( u16 fcs )

inlineprotectedinherited

Child class MUST call sreg_match(...) during write_finalize().

The child provides the FCS in a format that matches SREG.

Definition at line 164 of file io_checksum.h.

◆ sreg_push()

bool satcat5::io::ChecksumRx< u16 , N >::sreg_push ( u8 & data )

inlineprotectedinherited

Child class MUST call sreg_push(...) during write_next().

If it returns true, update the checksum state appropriately.

Definition at line 186 of file io_checksum.h.

◆ write_abort()

void ChecksumRxCommon::write_abort ( )

overridevirtualinherited

If possible, abort the current partially-written packet.

Child objects of io::Writeable SHOULD override this method if it is practical to prevent in-progress data from being relayed downstream.

Reimplemented from satcat5::io::Writeable.

Definition at line 42 of file io_checksum.cc.

◆ write_bytes()

void Writeable::write_bytes	(	unsigned	nbytes,
		const void *	src
	)

virtualinherited

Write 0 or more bytes from a buffer.

Child objects of io::Writeable MAY override write_bytes as needed for performance.

Reimplemented in satcat5::port::MailmapAligned, satcat5::port::Mailmap, satcat5::io::PacketBuffer, satcat5::io::MultiWriter, satcat5::io::MultiPacket::Overwriter, satcat5::io::NullWrite, satcat5::io::WriteableRedirect, satcat5::io::LimitedWrite, satcat5::io::CounterInline, satcat5::io::WriteableBroadcast, and satcat5::io::FileWriter.

Definition at line 170 of file io_writeable.cc.

◆ write_finalize()

bool KermitRx::write_finalize ( )

overridevirtual

Mark end of frame and release temporary working data.

Child objects of io::Writeable SHOULD override this method to mark frame bounds.

Returns: True if successful, false on error.

Reimplemented from satcat5::io::Writeable.

Definition at line 195 of file crc16_checksum.cc.

◆ write_next()

void KermitRx::write_next ( u8 data )

overrideprivatevirtual

Write the next byte to the underlying buffer or device.

Child objects of io::Writeable MUST override this method.

Implements satcat5::io::Writeable.

Definition at line 199 of file crc16_checksum.cc.

◆ write_overflow()

void Writeable::write_overflow ( )

protectedvirtualinherited

Optional error handling for write overflow.

Child objects of io::Writeable MAY override this method for error handling.

Reimplemented in satcat5::port::Mailmap, satcat5::io::PacketBuffer, satcat5::io::MultiWriter, satcat5::io::WriteableRedirect, satcat5::io::ArrayWrite, satcat5::io::ChecksumTxCommon, satcat5::io::WriteableBroadcast, satcat5::io::SlipDecoder, satcat5::io::SlipEncoder, satcat5::io::HdlcDecoder, satcat5::io::CobsDecoder, and satcat5::io::CobsEncoder.

Definition at line 187 of file io_writeable.cc.

◆ write_str()

void Writeable::write_str ( const char * str )

inherited

Write the contents of a null-terminated string.

Note: Null-termination is not copied to the output.

Definition at line 180 of file io_writeable.cc.

◆ write_u8()

void Writeable::write_u8 ( u8 data )

inherited

One of many functions for writing integer/floating point values, see details.

Several functions are provided for reading and writing scalar types to/from io::Readable and io::Writeable instances. Since there are many of these that are frequently inherited, they are hidden from documentation. These functions follow a shared template:

read_ or write_ prefix.
u for unsigned, s for signed, f for floating-point.
Data-type width in bits.
- Available widths for ints: 8/16/24/32/48/64.
- Available widths for floats: 32/64.
l suffix if little-endian, no suffix if big-endian.

Example: write_s48l is "Write 48 bits (6 bytes) to this io::Writeable as a signed value in little-endian order".

Definition at line 20 of file io_writeable.cc.

The documentation for this class was generated from the following files: