Non-owning manager for a fixed sequence of memory buffers, which is split into a read part and a write part, with a movable split position. More...

#include <rw_buffer_sequence.h>

Public Types
using	Buffer_sequence_view_t = Buffer_sequence_view< Char_tp, Container_tp >

using	Char_t = typename Buffer_sequence_view_t::Char_t

using	Size_t = typename Buffer_sequence_view_t::Size_t

using	Difference_t = std::ptrdiff_t

using	Buffer_view_t = typename Buffer_sequence_view_t::Buffer_view_t

using	Buffer_allocator_t = typename Buffer_sequence_view_t::Buffer_allocator_t

using	Container_t = typename Buffer_sequence_view_t::Container_t

using	Iterator_t = typename Buffer_sequence_view_t::Iterator_t

using	Const_iterator_t = typename Buffer_sequence_view_t::Const_iterator_t

using	Const_buffer_sequence_view_t = Buffer_sequence_view< Char_tp, Container_tp, true >

Public Member Functions
	Rw_buffer_sequence (Iterator_t begin_arg, Iterator_t end_arg)
	Construct a new Rw_buffer_sequence from given endpoint iterators, with position 0. More...

	Rw_buffer_sequence (Rw_buffer_sequence &)=delete

	Rw_buffer_sequence (Rw_buffer_sequence &&)=delete

Rw_buffer_sequence &	operator= (Rw_buffer_sequence &)=delete

Rw_buffer_sequence &	operator= (Rw_buffer_sequence &&)=delete

virtual	~Rw_buffer_sequence ()=default

void	set_position (Size_t new_position)
	Set the specified absolute position. More...

void	increase_position (Size_t delta)
	Move the position right, relative to the current position. More...

void	move_position (Difference_t delta)
	Move the position left or right, relative to the current position. More...

Size_t	capacity () const
	Return the current size, i.e., total size of all buffers. More...

const Buffer_sequence_view_t &	read_part () const
	Return a const reference to the read part. More...

Buffer_sequence_view_t &	read_part ()
	Return a non-const reference to the read part. More...

const Buffer_sequence_view_t &	write_part () const
	Return a const reference to the write part. More...

Buffer_sequence_view_t &	write_part ()
	Return a non-const reference to the write part. More...

virtual std::string	debug_string (bool show_contents, int indent) const
	In debug mode, return a string that describes the internal structure of this object, to use for debugging. More...

std::string	debug_string (bool show_contents=false) const
	In debug mode, return a string that describes the internal structure of this object, to use for debugging. More...

Static Protected Member Functions
static void	set_position (Size_t new_position, Buffer_sequence_view_t &left, Buffer_sequence_view_t &right)
	Move the position to the given, absolute position. More...

static Size_t	merge_if_split (Buffer_sequence_view_t &left, Buffer_sequence_view_t &right)
	If a buffer is split between the read and write parts, glue the pieces together again and include them in the read part. More...

static Size_t	move_position_one_buffer_left (Buffer_sequence_view_t &left, Buffer_sequence_view_t &right)
	Move the position exactly one buffer left, assuming no buffer is split. More...

static Size_t	move_position_at_most_one_buffer_right (Buffer_sequence_view_t &left, Buffer_sequence_view_t &right, Size_t limit)
	Move the position right by whatever is smaller: the given number, or one buffer; splits the buffer if the number is smaller than the buffer. More...

static std::tuple< Iterator_t, Iterator_t, Size_t >	get_boundaries (Buffer_sequence_view_t &buffer_sequence_view)
	Return the beginning, end, and size of the read and write parts. More...

Private Attributes
Buffer_sequence_view_t	m_read_part
	buffer_sequence_view for the (leading) read segment. More...

Buffer_sequence_view_t	m_write_part
	buffer_sequence_view for the (trailing) write segment. More...

Detailed Description

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>
class mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >

Non-owning manager for a fixed sequence of memory buffers, which is split into a read part and a write part, with a movable split position.

This has a read/write position (which Buffer_sequence does not have). It does not have functionailty to grow the buffer sequence (as Managed_buffer_sequence has).

Objects have one internal contiguous container (vector or list), which is split into two parts, each of which is a Buffer_sequence_view: the first part is the read part and the second part is the write part. API clients typically write to the write part and then move the position forwards: this will increase the read part so that API clients can read what was just written, and decrease the write part so that next write will happen after the position that was just written.

The position that defines the end of the read part and the beginning of the write part has byte granularity. Therefore, it does not have to be at a buffer boundary. When it is not on a buffer boundary, a buffer has to be split. When a buffer is split, the sequence needs one more element than the actual number of (contiguous) buffers. When the position is moved from a buffer boundary to a non-boundary, the number of used elements increases by one. To avoid having to shift all the buffers for the write part one step right when the container is a vector, there is always one more element than the actual number of contiguous buffers. So when the position is at a buffer boundary, an unused "null buffer" is stored between the read part and the write part. In other words, the buffer sequence has one of the following forms:

Position at buffer boundary:
Here, there are N buffers where the first R ones are read buffers.
  [b_1, ..., b_R, null, b_{R+1}, ..., b_N]
 
Position not at buffer boundary:
Here there are N buffers where the first R-1 ones are read buffers,
and the R'th one is split into a read part and a write part.
  [b_1, ..., b_R[0..x], b_R[x..], b_{R+1}, ..., b_N]

Template Parameters

Char_tp	the type of elements stored in the buffer: typically unsigned char.
Container_tp	the type of container: either `std::vector` or `std::list`.

Member Typedef Documentation

◆ Buffer_allocator_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Buffer_allocator_t = typename Buffer_sequence_view_t::Buffer_allocator_t

◆ Buffer_sequence_view_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Buffer_sequence_view_t = Buffer_sequence_view<Char_tp, Container_tp>

◆ Buffer_view_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Buffer_view_t = typename Buffer_sequence_view_t::Buffer_view_t

◆ Char_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Char_t = typename Buffer_sequence_view_t::Char_t

◆ Const_buffer_sequence_view_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Const_buffer_sequence_view_t = Buffer_sequence_view<Char_tp, Container_tp, true>

◆ Const_iterator_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Const_iterator_t = typename Buffer_sequence_view_t::Const_iterator_t

◆ Container_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Container_t = typename Buffer_sequence_view_t::Container_t

◆ Difference_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Difference_t = std::ptrdiff_t

◆ Iterator_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Iterator_t = typename Buffer_sequence_view_t::Iterator_t

◆ Size_t

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

using mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Size_t = typename Buffer_sequence_view_t::Size_t

Constructor & Destructor Documentation

◆ Rw_buffer_sequence() [1/3]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Rw_buffer_sequence	(	Iterator_t	begin_arg,
		Iterator_t	end_arg
	)

inline

Construct a new Rw_buffer_sequence from given endpoint iterators, with position 0.

The provided sequence of buffers must start with one null buffer, followed by zero or more non-null buffers.

Parameters

begin_arg	Iterator to the beginning of the sequence.
end_arg	Iterator to one-past-the-end of the sequence.

◆ Rw_buffer_sequence() [2/3]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Rw_buffer_sequence ( Rw_buffer_sequence< Char_tp, Container_tp > & )

delete

◆ Rw_buffer_sequence() [3/3]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::Rw_buffer_sequence ( Rw_buffer_sequence< Char_tp, Container_tp > && )

delete

◆ ~Rw_buffer_sequence()

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

virtual mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::~Rw_buffer_sequence ( )

virtualdefault

Member Function Documentation

◆ capacity()

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

Size_t mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::capacity ( ) const

inline

Return the current size, i.e., total size of all buffers.

◆ debug_string() [1/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

virtual std::string mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::debug_string	(	bool	show_contents,
		int	indent
	)		const

inlinevirtual

In debug mode, return a string that describes the internal structure of this object, to use for debugging.

Parameters

show_contents	If true, includes the buffer contents. Otherwise, just pointers and sizes.
indent	If 0, put all info on one line. Otherwise, put each field on its own line and indent the given number of two-space levels.

Reimplemented in mysql::containers::buffers::Managed_buffer_sequence< Char_tp, Container_tp >.

◆ debug_string() [2/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

std::string mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::debug_string ( bool show_contents = false ) const

inline

In debug mode, return a string that describes the internal structure of this object, to use for debugging.

Parameters

show_contents If true, includes the buffer contents. Otherwise, just pointers and sizes.

◆ get_boundaries()

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

static std::tuple< Iterator_t, Iterator_t, Size_t > mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::get_boundaries ( Buffer_sequence_view_t & buffer_sequence_view )

inlinestaticprotected

Return the beginning, end, and size of the read and write parts.

Parameters

buffer_sequence_view The buffer sequence view.

Returns: 3-tuple containing the beginning, size, and end of the given buffer_sequence_view.

◆ increase_position()

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

void mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::increase_position ( Size_t delta )

inline

Move the position right, relative to the current position.

"Position" is a synonym for "size of the read part".

Note: This may alter the end iterator of the read part, the begin iterator of the write part, as well as the begin/end iterators of buffers between the current position and the new position. The beginning of the read part, the end of the write part, and buffers outside the range between the new and old position remain unchanged.

Parameters

delta The number of bytes to add to the position. The resulting size must be within bounds; otherwise an assertion is raised in debug build, or the position forced to the beginning/end in non-debug build.

◆ merge_if_split()

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

static Size_t mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::merge_if_split	(	Buffer_sequence_view_t &	left,
		Buffer_sequence_view_t &	right
	)

inlinestaticprotected

If a buffer is split between the read and write parts, glue the pieces together again and include them in the read part.

If no buffer is split (the position is at a buffer boundary), does nothing.

Graphically, the operation is as follows:

+-----------------+-----------------+
| b1[0..split]    | b1[split..]     |
+-----------------+-----------------+
                    ^ read_end
                    ^ write_begin
-->
+-----------------+-----------------+
| b1              | null            |
+-----------------+-----------------+
                    ^ read_end        ^ write_begin

Parameters

left	The left buffer sequence.
right	The right buffer sequence.

Returns: The number of bytes that the position was moved left.

◆ move_position()

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

void mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::move_position ( Difference_t delta )

inline

Move the position left or right, relative to the current position.

"Position" is a synonym for "size of the read part".

Note: This may alter the end iterator of the read part, the begin iterator of the write part, as well as the begin/end iterators of buffers between the current position and the new position. The beginning of the read part, the end of the write part, and buffers outside the range between the new and old position remain unchanged.

Parameters

delta The number of bytes to add to the position. The resulting size must be within bounds; otherwise an assertion is raised in debug build, or the position forced to the beginning/end in non-debug build.

◆ move_position_at_most_one_buffer_right()

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

static Size_t mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::move_position_at_most_one_buffer_right	(	Buffer_sequence_view_t &	left,
		Buffer_sequence_view_t &	right,
		Size_t	limit
	)

inlinestaticprotected

Move the position right by whatever is smaller: the given number, or one buffer; splits the buffer if the number is smaller than the buffer.

Parameters

left	The left buffer sequence.
right	The right buffer sequence.
limit	Move the position at most this number of bytes right.

Returns: The number of bytes that the position was moved right.

◆ move_position_one_buffer_left()

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

static Size_t mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::move_position_one_buffer_left	(	Buffer_sequence_view_t &	left,
		Buffer_sequence_view_t &	right
	)

inlinestaticprotected

Move the position exactly one buffer left, assuming no buffer is split.

Graphically, the operation is as follows:

+-----------------+-----------------+
| b1              | null            |
+-----------------+-----------------+
                    ^ read_end        ^ write_begin
-->
+-----------------+-----------------+
| null            | b1              |
+-----------------+-----------------+
  ^ read_end        ^ write_begin

Parameters

left	The left buffer sequence.
right	The right buffer sequence.

Returns: The number of bytes that the position was moved left.

◆ operator=() [1/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

Rw_buffer_sequence & mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::operator= ( Rw_buffer_sequence< Char_tp, Container_tp > && )

delete

◆ operator=() [2/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

Rw_buffer_sequence & mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::operator= ( Rw_buffer_sequence< Char_tp, Container_tp > & )

delete

◆ read_part() [1/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

Buffer_sequence_view_t & mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::read_part ( )

inline

Return a non-const reference to the read part.

◆ read_part() [2/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

const Buffer_sequence_view_t & mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::read_part ( ) const

inline

Return a const reference to the read part.

◆ set_position() [1/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

void mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::set_position ( Size_t new_position )

inline

Set the specified absolute position.

"Position" is a synonym for "size of the read part".

Note: This may alter the end iterator of the read part, the begin iterator of the write part, as well as the begin/end iterators of buffers between the current position and the new position. The beginning of the read part, the end of the write part, and buffers outside the range between the new and old position remain unchanged.

Parameters

new_position The new size of the read part. This must be within bounds; otherwise an assertion is raised in debug build, or the position forced to the end in non-debug build.

◆ set_position() [2/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

static void mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::set_position	(	Size_t	new_position,
		Buffer_sequence_view_t &	left,
		Buffer_sequence_view_t &	right
	)

inlinestaticprotected

Move the position to the given, absolute position.

Note: This may alter the end iterator of the left part, the begin iterator of the right part, as well as the begin/end iterators of buffers between the current position and the new position. The beginning of the left part, the end of the right part, and buffers outside the range between the new and old position remain unchanged.

Parameters

new_position	The new position. This must be within bounds. Otherwise an assertion is raised in debug build; in non-debug build, the position is forced to the end.
left	The left buffer sequence.
right	The right buffer sequence.

Note: One of the following must hold: (1) the container has one element between the left part and the right part, and that element is a null buffer; (2) left.end()==right.begin() && left.end().end()==right.begin().begin().

◆ write_part() [1/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

Buffer_sequence_view_t & mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::write_part ( )

inline

Return a non-const reference to the write part.

◆ write_part() [2/2]

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

const Buffer_sequence_view_t & mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::write_part ( ) const

inline

Return a const reference to the write part.

Member Data Documentation

◆ m_read_part

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

Buffer_sequence_view_t mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::m_read_part

private

buffer_sequence_view for the (leading) read segment.

◆ m_write_part

template<class Char_tp = unsigned char, template< class Element_tp, class Allocator_tp > class Container_tp = std::vector>

Buffer_sequence_view_t mysql::containers::buffers::Rw_buffer_sequence< Char_tp, Container_tp >::m_write_part

private

buffer_sequence_view for the (trailing) write segment.

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

libs/mysql/containers/buffers/rw_buffer_sequence.h

Public Types

Public Member Functions

Static Protected Member Functions

Private Attributes

Detailed Description

Member Typedef Documentation

◆ Buffer_allocator_t

◆ Buffer_sequence_view_t

◆ Buffer_view_t

◆ Char_t

◆ Const_buffer_sequence_view_t

◆ Const_iterator_t

◆ Container_t

◆ Difference_t

◆ Iterator_t

◆ Size_t

Constructor & Destructor Documentation

◆ Rw_buffer_sequence() [1/3]

◆ Rw_buffer_sequence() [2/3]

◆ Rw_buffer_sequence() [3/3]

◆ ~Rw_buffer_sequence()

Member Function Documentation

◆ capacity()

◆ debug_string() [1/2]

◆ debug_string() [2/2]

◆ get_boundaries()

◆ increase_position()

◆ merge_if_split()

◆ move_position()

◆ move_position_at_most_one_buffer_right()

◆ move_position_one_buffer_left()

◆ operator=() [1/2]

◆ operator=() [2/2]

◆ read_part() [1/2]

◆ read_part() [2/2]

◆ set_position() [1/2]

◆ set_position() [2/2]

◆ write_part() [1/2]

◆ write_part() [2/2]

Member Data Documentation

◆ m_read_part

◆ m_write_part