qi::Buffer Class Reference

Class to store buffer. More...

#include <buffer.hpp>

Public Member Functions
	Buffer ()
	Default constructor. More...
	Buffer (const Buffer &b)
	Copy constructor. More...
Buffer &	operator= (const Buffer &b)
	Assignment operator. More...
bool	write (const void *data, size_t size)
	Write data in the buffer. More...
size_t	addSubBuffer (const Buffer &buffer)
	Add a sub-buffer to the main buffer. More...
bool	hasSubBuffer (size_t offset) const
	Check if there is a sub-buffer at given offset. More...
const Buffer &	subBuffer (size_t offset) const
	Return the sub-buffer at given offset. More...
size_t	size () const
	Return the content size of this buffer not counting sub-buffers. More...
size_t	totalSize () const
	Return the content size of this buffer and of all its sub-buffers. More...
const std::vector< std::pair < size_t, Buffer > > &	subBuffers () const
	Return a vector of sub-buffers of the current buffer. More...
void *	reserve (size_t size)
	Reserve bytes at the end of current buffer. More...
void	clear ()
	Erase content of buffer and remove sub-buffers whithout clearing them. More...
void *	data ()
	Return a pointer to the raw data storage of this buffer. More...
const void *	data () const
	Return a const pointer to the raw data in this buffer. More...
const void *	read (size_t offset=0, size_t length=0) const
	Read some data from the buffer. More...
size_t	read (void *buffer, size_t offset=0, size_t length=0) const
	Read some data in the buffer and store it in a new pre-allocated buffer. More...

Friends
class	BufferReader

Detailed Description

Class to store buffer.

* This class can store buffer and sub-buffers.
* Here is a representation of internal management of sub-buffers.
*
* .. graphviz::
*
*      digraph g {
*          graph [ rankdir = "LR" ];
*          node [ fontsize = "16", shape = "ellipse" ];
*
*          subgraph cluster_buffer {
*              mainbuffer;
*              label = "Main buffer";
*          }
*
*          subgraph cluster_subbuffer1 {
*              subbuffer1;
*              label = "Sub-buffer 1";
*          }
*
*          subgraph cluster_subbuffer2 {
*              subbuffer2;
*              label = "Sub-buffer 2";
*          }
*
*          "mainbuffer" [
*              label = "...| ...| ...| ...| ...| ...|<f0> uint32_t subBufferSize| ...| ...|<f1> uint32_t subBufferSize| ...| ...| ..."
*              shape = "record"
*          ];
*          "subbuffer1" [
*              label = "<f0> ...| ...|...| ...|  ...|  ...| ...| ...| ...| ..."
*              shape = "record"
*          ];
*          "subbuffer2" [
*              label = "<f0> ...| ...|...| ...|  ...|  ...| ...| ...| ...| ..."
*              shape = "record"
*          ];
*          "mainbuffer":f0-> "subbuffer1":f0[
*              id = 0
*          ];
*          "mainbuffer":f1-> "subbuffer2":f0[
*              id = 0
*          ];
*      }
*
* 

Definition at line 26 of file buffer.hpp.

Constructor & Destructor Documentation

qi::Buffer::Buffer

(

)

Default constructor.

qi::Buffer::Buffer

(

const Buffer &

buffer

)

Copy constructor.

As data are store as a shared pointer, the different copy of the same buffer all handle the same data.

Parameters

buffer

The buffer to copy.

Member Function Documentation

qi::Buffer::addSubBuffer

(

const Buffer &

buffer

)

Add a sub-buffer to the main buffer.

This function add a uint32_t for the size of sub-buffers in main buffer and add the buffer to the list of sub-buffers.

Parameters

buffer

The buffer to have as sub-buffer.

Returns

return te offset at which sub-buffer have been added.

qi::Buffer::clear

(

)

Erase content of buffer and remove sub-buffers whithout clearing them.

qi::Buffer::data

(

)

Return a pointer to the raw data storage of this buffer.

Returns

the pointer to the data.

qi::Buffer::data

(

)

const

Return a const pointer to the raw data in this buffer.

Returns

the pointer to the data.

qi::Buffer::hasSubBuffer

(

size_t

offset

)

const

Check if there is a sub-buffer at given offset.

Parameters

offset

The offset to look at the presence of sub-buffer.

Returns

true if there is a sub-buffer, false otherwise.

qi::Buffer::operator=

(

const Buffer &

buffer

)

Assignment operator.

As data are store as a shared pointer, the different copy of the same buffer all handle the same data.

Parameters

buffer

The buffer to copy.

qi::Buffer::read	(	size_t	offset = 0,
		size_t	length = 0
	)		const

Read some data from the buffer.

Parameters

offset	offset at which reading begin in the buffer.
length	length of the data to read.

Returns

0 if the buffer is empty or if we try to read data after the end of the buffer.
Otherwise return a pointer to the data. Only length bytes can be read in the returned buffer.

qi::Buffer::read	(	void *	buffer,
		size_t	offset = 0,
		size_t	length = 0
	)		const

Read some data in the buffer and store it in a new pre-allocated buffer.

Warning

the given buffer must be freed.

Parameters

buffer	the pre-allocated buffer to store data.
offset	Offset in the current buffer to start copy.
length	Length of the data to be copied.

Returns

-1 if there is no data in buffer or if offset is bigger than total data in buffer.
Otherwise return the total length of copied data.

qi::Buffer::reserve

(

size_t

size

)

Reserve bytes at the end of current buffer.

Parameters

size	number of new bytes to reserve at the end of buffer.

Returns

a pointer to the data.

Warning

The return value is valid until the next non-const operation.

qi::Buffer::size

(

)

const

Return the content size of this buffer not counting sub-buffers.

Returns

the size.

See Also

totalSize

qi::Buffer::subBuffer

(

size_t

offset

)

const

Return the sub-buffer at given offset.

If there is no sub-buffer throw a std::runtime_error.

Parameters

offset

The offset to look for sub-buffer.

Returns

the sub-buffer.

qi::Buffer::subBuffers

(

)

const

Return a vector of sub-buffers of the current buffer.

Returns

a vector of pairs. The first value of the pair is the offset of the sub-buffer into the master buffer. The second value is the sub-buffer itself.

qi::Buffer::totalSize

(

)

const

Return the content size of this buffer and of all its sub-buffers.

Returns

the size.

See Also

size

qi::Buffer::write	(	const void *	data,
		size_t	size
	)

Write data in the buffer.

Parameters

data	The data to write
size	The size of the data to write

Returns

true if operation succeeded, false otherwise.

Friends And Related Function Documentation

friend class BufferReader

friend

Definition at line 70 of file buffer.hpp.

---

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

• /home/opennao/work/master/sdk/libqi/qi/buffer.hpp
• /home/opennao/work/master/sdk/libqi/qi/buffer.dox