Detailed Description

Extensible transmit and receive buffer.

The BufferedIO class provides a flexible software buffer for use with hardware I/O functions, such as Ethernet, I2C, and UART ports. It grants the public Writable and Readable interfaces and makes the buffered data available to the inner class. To use, set up a parent class that:

Inherits from BufferedIO.
Provides the raw working buffers for each PacketBuffer instance.
Passes the parameters for these to the BufferedIO constructor. (These buffers can be used in packet mode or contiguous mode.)
Implements the data_rcvd() method to handle new outgoing data. (i.e., By calling the read_xx methods on m_tx.)
Writes any incoming received data to the m_rx buffer.

The child SHOULD access each PacketBuffer m_tx and m_rx directly and MUST implement EventListener::data_rcvd().

Definition at line 38 of file io_buffer.h.

#include <io_buffer.h>

Inheritance diagram for satcat5::io::BufferedIO:

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Collaboration diagram for satcat5::io::BufferedIO:

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Public Member Functions
void	set_callback (satcat5::io::EventListener *callback) override
	Update registered callback for data_rcvd() events. More...

unsigned	get_read_ready () const override
	How many bytes can be read without blocking? More...

bool	read_bytes (unsigned nbytes, void *dst) override
	Read 0 or more bytes into a buffer. More...

bool	read_consume (unsigned nbytes) override
	Read and discard 0 or more bytes. More...

void	read_finalize () override
	Consume any remaining bytes in this frame, if applicable. More...

u8	read_u8 ()
	One of many functions for reading integer/floating point values, see details. More...

unsigned	read_str (unsigned dst_size, char *dst)
	Safely read a null-terminated input string. More...

template<class T >
bool	read_obj (T &t)
	Templated wrapper for any object with the following method: `bool read_from(satcat5::io::Readable* rd);`

unsigned	copy_to (satcat5::io::Writeable *dst)
	Copy data to a Writeable object, without finalizing. More...

bool	copy_and_finalize (satcat5::io::Writeable *dst, satcat5::io::CopyMode mode=CopyMode::PACKET)
	Copy data to a Writeable object, then finalize. More...

void	request_poll ()
	Call this method to request polling at a later time. More...

void	request_cancel ()
	Call this method to cancel a previous request_poll().

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...

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

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

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

Static Public Member Functions
static unsigned	count_ondemand ()
	Count queued objects of this type (i.e., non-idle).

Protected Member Functions
	BufferedIO (u8 txbuff, unsigned txbytes, unsigned txpkt, u8 rxbuff, unsigned rxbytes, unsigned rxpkt)
	Child provides Tx and Rx working buffers. More...

u8	read_next () override
	Read the next byte from the underlying buffer or device. More...

void	read_underflow () override
	Optional error handling for read underflow. More...

void	read_src (satcat5::io::Readable *src)
	Children may reset the source object as needed.

void	read_notify ()
	Attempt notification by calling `m_callback->data_rcvd()`. More...

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

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

void	write_dst (satcat5::io::Writeable *dst)

virtual void	data_rcvd (satcat5::io::Readable *src)=0
	The data_rcvd() callback is polled whenever data is available. More...

virtual void	data_unlink (satcat5::io::Readable *src)
	Unlink this EventListener from the designated source, because the designated Readable object is being destroyed. More...

Protected Attributes
satcat5::io::PacketBuffer	m_tx
	Transmit data (user writes, child reads)

satcat5::io::PacketBuffer	m_rx
	Receive data (user reads, child writes)

friend	WriteableRedirect

friend	LimitedWrite

friend	WriteableBroadcast

Private Member Functions
void	poll_demand ()
	Event handler for on-demand polling.

Private Attributes
satcat5::io::Readable *	m_src

satcat5::io::EventListener *	m_callback
	Pointer to the callback object, or NULL. More...

satcat5::poll::OnDemand *	m_next

bool	m_idle

satcat5::io::Writeable *	m_dst

Constructor & Destructor Documentation

◆ BufferedIO()

BufferedIO::BufferedIO	(	u8 *	txbuff,
		unsigned	txbytes,
		unsigned	txpkt,
		u8 *	rxbuff,
		unsigned	rxbytes,
		unsigned	rxpkt
	)

protected

Child provides Tx and Rx working buffers.

The child class provides the transmit and/or receive buffers. Transmit-only or receive-only child objects may provide a null pointer for the unused buffer.

Definition at line 16 of file io_buffer.cc.

Member Function Documentation

◆ copy_and_finalize()

bool Readable::copy_and_finalize	(	satcat5::io::Writeable *	dst,
		satcat5::io::CopyMode	mode = `CopyMode::PACKET`
	)

inherited

Copy data to a Writeable object, then finalize.

As copy_to(), but also calls read_finalize() and/or write_finalize() depending on the input/output mode.

In packet mode (the default), call both read_finalize() and write_finalize() if the operation copies all available data. Use this mode whenever the input is packetized.

In byte-stream mode, call write_finalize() if the operation copies any data, but never call read_finalize(). Use this mode for inputs that do not delimit packet boundaries.

Parameters

dst	The destination object.
mode	Select packet mode or stream mode.

Returns: True if the output was finalized successfully.

Definition at line 234 of file io_readable.cc.

◆ copy_to()

unsigned Readable::copy_to ( satcat5::io::Writeable * dst )

inherited

Copy data to a Writeable object, without finalizing.

Copy the contents of this Readable to a Writeable object, stopping at end-of-input, end-of-frame, or the capacity of the destination buffer (whichever comes first). This method does not call read_finalize or write_finalize(). To automatically make finalize calls,

See also: copy_and_finalize.

Returns: The number of bytes copied.

Definition at line 214 of file io_readable.cc.

◆ data_rcvd()

virtual void satcat5::io::EventListener::data_rcvd ( satcat5::io::Readable * src )

pure virtualinherited

The data_rcvd() callback is polled whenever data is available.

A pointer is provided to assist handlers with multiple sources. Child objects of io::EventListener MUST override this method.

Implemented in satcat5::port::Mailbox, satcat5::io::PacketCombiner, satcat5::net::Tpipe, satcat5::net::SocketCore, satcat5::io::NullSink, satcat5::io::Override, satcat5::io::MuxUp, satcat5::io::MuxDown, satcat5::io::BufferedPackets, satcat5::io::BufferedStream, satcat5::io::BufferedCopy, satcat5::eth::SwitchPort, satcat5::eth::SwitchLogReader, satcat5::eth::Dispatch, satcat5::io::RtttlDecoder, satcat5::cfg::Piezo, satcat5::cfg::MultiSerial, satcat5::ccsds_spp::Dispatch, satcat5::ccsds_aos::Dispatch, satcat5::ccsds_aos::Channel, satcat5::test::MockOffload::Port, satcat5::test::EthernetInterface, satcat5::sam::UsartSamv71, satcat5::tcp::SocketPosix, satcat5::io::PosixUart, satcat5::pcap::Socket, satcat5::freertos::MessageCopy, satcat5::cfg::Uart, satcat5::cfg::Hdlc, satcat5::test::IoEventCounter, and satcat5::freertos::StreamBuffer.

◆ data_unlink()

virtual void satcat5::io::EventListener::data_unlink ( satcat5::io::Readable * src )

inlinevirtualinherited

Unlink this EventListener from the designated source, because the designated Readable object is being destroyed.

Child objects of io::EventListener MAY override this method if action is required.

Reimplemented in satcat5::io::Override, satcat5::io::MuxUp, satcat5::io::MuxDown, satcat5::io::BufferedPackets, satcat5::io::BufferedStream, satcat5::io::BufferedCopy, satcat5::eth::SwitchLogReader, satcat5::eth::Dispatch, satcat5::ccsds_spp::Dispatch, satcat5::ccsds_aos::Dispatch, satcat5::ccsds_aos::Channel, satcat5::test::MockOffload::Port, and satcat5::freertos::MessageCopy.

Definition at line 54 of file io_readable.h.

◆ get_read_ready()

unsigned ReadableRedirect::get_read_ready ( ) const

overridevirtualinherited

How many bytes can be read without blocking?

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

Implements satcat5::io::Readable.

Definition at line 336 of file io_readable.cc.

◆ get_write_space()

unsigned WriteableRedirect::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 236 of file io_writeable.cc.

◆ read_bytes()

bool ReadableRedirect::read_bytes	(	unsigned	nbytes,
		void *	dst
	)

overridevirtualinherited

Read 0 or more bytes into a buffer.

Child objects of io::Readable MAY override this method for improved performance.

Reimplemented from satcat5::io::Readable.

Definition at line 339 of file io_readable.cc.

◆ read_consume()

bool ReadableRedirect::read_consume ( unsigned nbytes )

overridevirtualinherited

Read and discard 0 or more bytes.

Child objects of io::Readable MAY override this method for improved performance.

Reimplemented from satcat5::io::Readable.

Definition at line 342 of file io_readable.cc.

◆ read_finalize()

void ReadableRedirect::read_finalize ( )

overridevirtualinherited

Consume any remaining bytes in this frame, if applicable.

Child objects of io::Readable SHOULD override this method if they support framing.

Reimplemented from satcat5::io::Readable.

Definition at line 345 of file io_readable.cc.

◆ read_next()

u8 ReadableRedirect::read_next ( )

overrideprotectedvirtualinherited

Read the next byte from the underlying buffer or device.

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

Implements satcat5::io::Readable.

Definition at line 348 of file io_readable.cc.

◆ read_notify()

void Readable::read_notify ( )

protectedinherited

Attempt notification by calling m_callback->data_rcvd().

Child objects of io::Readable MAY call this to override default notifications.

Definition at line 254 of file io_readable.cc.

◆ read_str()

unsigned Readable::read_str	(	unsigned	dst_size,
		char *	dst
	)

inherited

Safely read a null-terminated input string.

The input is always consumed up to the end-of-input or the first zero byte, whichever comes first.

Returns: The length of the output string, which may be truncated as needed to fit in the provided buffer.

Definition at line 179 of file io_readable.cc.

◆ read_u8()

u8 Readable::read_u8 ( )

inherited

One of many functions for reading 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 44 of file io_readable.cc.

◆ read_underflow()

void ReadableRedirect::read_underflow ( )

overrideprotectedvirtualinherited

Optional error handling for read underflow.

Child objects of io::Readable MAY override this method.

Reimplemented from satcat5::io::Readable.

Definition at line 351 of file io_readable.cc.

◆ request_poll()

void satcat5::poll::OnDemand::request_poll ( )

inherited

Call this method to request polling at a later time.

Safe to stack requests, but only one call to poll().

Definition at line 208 of file polling.cc.

◆ set_callback()

void ReadableRedirect::set_callback ( satcat5::io::EventListener * callback )

overridevirtualinherited

Update registered callback for data_rcvd() events.

Child objects of io::Readable SHOULD usually leave this method as-is.

Reimplemented from satcat5::io::Readable.

Definition at line 331 of file io_readable.cc.

◆ write_abort()

void WriteableRedirect::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 239 of file io_writeable.cc.

◆ write_bytes()

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

overridevirtualinherited

Write 0 or more bytes from a buffer.

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

Reimplemented from satcat5::io::Writeable.

Definition at line 242 of file io_writeable.cc.

◆ write_finalize()

bool WriteableRedirect::write_finalize ( )

overridevirtualinherited

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 245 of file io_writeable.cc.

◆ write_next()

void WriteableRedirect::write_next ( u8 data )

overrideprotectedvirtualinherited

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 248 of file io_writeable.cc.

◆ write_overflow()

void WriteableRedirect::write_overflow ( )

overrideprotectedvirtualinherited

Optional error handling for write overflow.

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

Reimplemented from satcat5::io::Writeable.

Definition at line 251 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.

Member Data Documentation

◆ m_callback

satcat5::io::EventListener* satcat5::io::Readable::m_callback

privateinherited

Pointer to the callback object, or NULL.

This can only be modified through the set_callback(...) method.

Definition at line 199 of file io_readable.h.

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

Detailed Description

Public Member Functions

Static Public Member Functions

Protected Member Functions

Protected Attributes

Private Member Functions

Private Attributes

Constructor & Destructor Documentation

◆ BufferedIO()

Member Function Documentation

◆ copy_and_finalize()

◆ copy_to()

◆ data_rcvd()

◆ data_unlink()

◆ get_read_ready()

◆ get_write_space()

◆ read_bytes()

◆ read_consume()

◆ read_finalize()

◆ read_next()

◆ read_notify()

◆ read_str()

◆ read_u8()

◆ read_underflow()

◆ request_poll()

◆ set_callback()

◆ write_abort()

◆ write_bytes()

◆ write_finalize()

◆ write_next()

◆ write_overflow()

◆ write_str()

◆ write_u8()

Member Data Documentation

◆ m_callback