satcat5::io::WriteableRedirect Class Reference

Detailed Description

Wrapper class for forwarding writes to another object.

This class is used to add a Writeable interface to an object by forwarding all API calls to another object.

An example usage is a UART driver. From a user's perspective, outgoing data is written to the UART. Using WriteableRedirect, the UART driver can forward that data to a software FIFO object, then copy data from the FIFO to the UART hardware.

To use this class, create a new class that inherits from WriteableRedirect. The constructor sets the forwarding address.

Definition at line 218 of file io_writeable.h.

#include <io_writeable.h>

Inheritance diagram for satcat5::io::WriteableRedirect:

Collaboration diagram for satcat5::io::WriteableRedirect:

Public Member Functions
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;

Protected Member Functions
constexpr	WriteableRedirect (satcat5::io::Writeable *dst)
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)

Protected Attributes
friend	LimitedWrite
friend	WriteableBroadcast
friend	WriteableRedirect

Private Attributes
satcat5::io::Writeable *	m_dst

Member Function Documentation

get_write_space()

unsigned WriteableRedirect::get_write_space ( ) const

overridevirtual

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.

write_abort()

void WriteableRedirect::write_abort ( )

overridevirtual

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  )

overridevirtual

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 ( )

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 245 of file io_writeable.cc.

write_next()

void WriteableRedirect::write_next ( u8  data )

overrideprotectedvirtual

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 ( )

overrideprotectedvirtual

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.

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

• io_writeable.h
• io_writeable.cc