pabigot::byteorder::octets_helper Class Reference

Infrastructure to fill an octet buffer with data. More...

#include </mnt/devel/pabigot-cxx/include/pabigot/byteorder.hpp>

Inheritance diagram for pabigot::byteorder::octets_helper:

Public Types
using	size_type = std::size_t
	Type used for span values.

Public Member Functions
	octets_helper (uint8_t *begin, uint8_t *end)
	Reference an octet range into which data will be written. More...
	octets_helper (uint8_t *begin, size_type count)
	Reference an octet sequence into which data will be written. More...
void	reset () noexcept
	Remove all content from the buffer. More...
const bool	valid () const noexcept
	Indicates whether advance() caused an error. More...
void	invalidate () noexcept
	Explicitly mark the buffer invalid. More...
const void *	begin () const noexcept
	Get a pointer to the start of buffer. More...
const void *	end () const noexcept
	Get a pointer to the end of the filled part of the buffer. More...
const size_type	size () const noexcept
	Number of octets stored in the buffer. More...
const size_type	available () const noexcept
	Number of unused octets available in the buffer. More...
const size_type	max_size () const noexcept
	Maximum number of octets supported by the buffer.
void *	advance (size_type s) noexcept
	Allocate a region and return a pointer to it or a nullptr if the advance went too far. More...
bool	can_advance (size_type s) const noexcept
	Indicate whether advance() would succeed for a given span. More...
bool	append (const void *sp, size_type span) noexcept
	Append a value to the buffer. More...
template<typename T >
bool	append (const T &value) noexcept
	Append a value to the buffer. More...
template<typename T >
bool	append_be (const T &value) noexcept
	As with append() but stores the value converted to big-endian byte order.
template<typename T >
bool	append_le (const T &value) noexcept
	As with append() but stores the value converted to little-endian byte order.

Protected Attributes
uint8_t *const	begin_
uint8_t *const	end_
uint8_t *	bp_ = nullptr

Friends
class	oob_helper

Detailed Description

Infrastructure to fill an octet buffer with data.

This allows safe invocation for as much data is desired, allowing overrun detection at the end rather than on each addition.

Note

This structure references but does not own the memory of the buffer that it manages.

Constructor & Destructor Documentation

octets_helper() [1/2]

pabigot::byteorder::octets_helper::octets_helper ( uint8_t *  begin, uint8_t *  end  )

inline

Reference an octet range into which data will be written.

Parameters

begin	pointer to the first octet in the sequence.
end	pointer just past the last octet available for the sequence.

octets_helper() [2/2]

pabigot::byteorder::octets_helper::octets_helper ( uint8_t *  begin, size_type  count  )

inline

Reference an octet sequence into which data will be written.

Parameters

begin	pointer to the first octet in the sequence.
count	the number of octets in the sequence.

Member Function Documentation

advance()

void* pabigot::byteorder::octets_helper::advance ( size_type  s )

inlinenoexcept

Allocate a region and return a pointer to it or a nullptr if the advance went too far.

Parameters

s	the number of octets required.

Returns

a pointer into the allocated buffer that allows writing s octets. The pointer is null (and valid() will now return false) if the buffer had already become invalid, or did so as a result of advancing by s.

append() [1/2]

template<typename T >

bool pabigot::byteorder::octets_helper::append ( const T &  value )

inlinenoexcept

Append a value to the buffer.

The byte-order of the value is native. If a non-native order is required use append_le() or append_be(), or use host_x_le() or host_x_be() on the argument.

Template Parameters

T	the underlying type of the value.

Parameters

value

the value to append.

Returns

as with advance()

append() [2/2]

bool pabigot::byteorder::octets_helper::append ( const void *  sp, size_type  span  )

inlinenoexcept

Append a value to the buffer.

This invokes advance() and if the space reservation was successful stores the range.

Parameters

sp	pointer to the value to be appended.
span	the number of octets to be appended.

Returns

as with advance()

available()

const size_type pabigot::byteorder::octets_helper::available ( ) const

inlinenoexcept

Number of unused octets available in the buffer.

Note

The returned size is zero if not valid.

begin()

const void* pabigot::byteorder::octets_helper::begin ( ) const

inlinenoexcept

Get a pointer to the start of buffer.

Returns

as described, but a null pointer if not valid.

can_advance()

bool pabigot::byteorder::octets_helper::can_advance ( size_type  s ) const

inlinenoexcept

Indicate whether advance() would succeed for a given span.

Parameters

s	as with advance()

Returns

true if the buffer is valid and has sufficient space for s octets, otherwise false. A false return does not invalidate a valid buffer.

end()

const void* pabigot::byteorder::octets_helper::end ( ) const

inlinenoexcept

Get a pointer to the end of the filled part of the buffer.

I.e. the span from [begin(), end()) has filled content.

Returns

as described, but a null pointer if not valid.

invalidate()

void pabigot::byteorder::octets_helper::invalidate ( )

inlinenoexcept

Explicitly mark the buffer invalid.

This might be used by subclasses that use a more piece-wise conception of whether an allocation will fit.

reset()

void pabigot::byteorder::octets_helper::reset ( )

inlinenoexcept

Remove all content from the buffer.

After this valid() will be true, the buffer will be zeroed, and the next write will begin at the buffer start.

size()

const size_type pabigot::byteorder::octets_helper::size ( ) const

inlinenoexcept

Number of octets stored in the buffer.

Note

The returned size is zero if not valid.

valid()

const bool pabigot::byteorder::octets_helper::valid ( ) const

inlinenoexcept

Indicates whether advance() caused an error.

Returns

false iff advance() was invoked to reserve more space than was available or invalidate() was called since the last reset().

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

• /mnt/devel/pabigot-cxx/include/pabigot/byteorder.hpp