Detailed Description

Abstract API for reading byte-streams and packets.

The abstract Readable interface is for reading data from a device or buffer. Anything that provides a byte-stream, with or without packets, should usually implement this interface to allow flexible reconnection with other SatCat5 tools.

Note: If frame boundaries are supported, read_* methods MUST NOT read past the boundary until read_finalize() is called.

Definition at line 68 of file io_readable.h.

#include <io_readable.h>

Inheritance diagram for satcat5::io::Readable:

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Collaboration diagram for satcat5::io::Readable:

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

virtual unsigned	get_read_ready () const =0
	How many bytes can be read without blocking? More...

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

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

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

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

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

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

Protected Member Functions
constexpr	Readable (satcat5::io::EventListener *callback=0)
	Only children should create or destroy the base class.

virtual u8	read_next ()=0
	Read the next byte from the underlying buffer or device. More...

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

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

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

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

satcat5::poll::OnDemand *	m_next

bool	m_idle

Member Function Documentation

◆ copy_and_finalize()

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

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 )

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.

◆ get_read_ready()

virtual unsigned satcat5::io::Readable::get_read_ready ( ) const

pure virtual

How many bytes can be read without blocking?

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

Implemented in satcat5::port::Mailmap, satcat5::io::PacketBuffer, satcat5::io::MultiPacket::Reader, satcat5::io::NullRead, satcat5::io::ReadableRedirect, satcat5::io::LimitedRead, satcat5::io::ArrayRead, and satcat5::io::FileReader.

◆ read_bytes()

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

virtual

Read 0 or more bytes into a buffer.

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

Reimplemented in satcat5::port::MailmapAligned, satcat5::port::Mailmap, satcat5::io::PacketBuffer, satcat5::io::MultiPacket::Reader, satcat5::io::ReadableRedirect, satcat5::io::LimitedRead, and satcat5::io::FileReader.

Definition at line 190 of file io_readable.cc.

◆ read_consume()

bool Readable::read_consume ( unsigned nbytes )

virtual

Read and discard 0 or more bytes.

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

Reimplemented in satcat5::io::PacketBuffer, satcat5::io::MultiPacket::Reader, satcat5::io::ReadableRedirect, satcat5::io::LimitedRead, and satcat5::io::FileReader.

Definition at line 204 of file io_readable.cc.

◆ read_finalize()

void Readable::read_finalize ( )

virtual

Consume any remaining bytes in this frame, if applicable.

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

Reimplemented in satcat5::port::Mailmap, satcat5::io::PacketBuffer, satcat5::io::MultiReader, satcat5::io::MultiPacket::Reader, satcat5::io::ReadableRedirect, satcat5::io::LimitedRead, satcat5::io::ArrayRead, satcat5::test::EthernetInterface, satcat5::io::ReadPcap, and satcat5::io::FileReader.

Definition at line 270 of file io_readable.cc.

◆ read_next()

virtual u8 satcat5::io::Readable::read_next ( )

protectedpure virtual

Read the next byte from the underlying buffer or device.

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

Implemented in satcat5::port::MailmapAligned, satcat5::port::Mailmap, satcat5::io::PacketBuffer, satcat5::io::MultiPacket::Reader, satcat5::io::NullRead, satcat5::io::ReadableRedirect, satcat5::io::LimitedRead, satcat5::io::ArrayRead, and satcat5::io::FileReader.

◆ read_notify()

void Readable::read_notify ( )

protected

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
	)

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 ( )

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 Readable::read_underflow ( )

protectedvirtual

Optional error handling for read underflow.

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

Reimplemented in satcat5::port::Mailmap, and satcat5::io::ReadableRedirect.

Definition at line 271 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 Readable::set_callback ( satcat5::io::EventListener * callback )

virtual

Update registered callback for data_rcvd() events.

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

Reimplemented in satcat5::io::ReadableRedirect, satcat5::io::Override, satcat5::io::MuxPort, and satcat5::test::EthernetInterface.

Definition at line 39 of file io_readable.cc.

Member Data Documentation

◆ m_callback

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

private

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

Private Member Functions

Private Attributes

Member Function Documentation

◆ copy_and_finalize()

◆ copy_to()

◆ get_read_ready()

◆ read_bytes()

◆ read_consume()

◆ read_finalize()

◆ read_next()

◆ read_notify()

◆ read_str()

◆ read_u8()

◆ read_underflow()

◆ request_poll()

◆ set_callback()

Member Data Documentation

◆ m_callback