wxMemoryBuffer Class Reference

#include <wx/buffer.h>

Detailed Description

A wxMemoryBuffer is a useful data structure for storing arbitrary sized blocks of memory.

wxMemoryBuffer guarantees deletion of the memory block when the object is destroyed.

Library:  wxBase

Category:  Data Structures

Public Member Functions
	wxMemoryBuffer (const wxMemoryBuffer &src)
	Copy constructor, refcounting is used for performance, but wxMemoryBuffer is not a copy-on-write structure so changes made to one buffer effect all copies made from it.
	wxMemoryBuffer (size_t size=1024)
	Create a new buffer.
void	AppendByte (char data)
	Append a single byte to the buffer.
void	AppendData (const void *data, size_t len)
	Single call to append a data block to the buffer.
void	Clear ()
	Clear the buffer contents.
void *	GetAppendBuf (size_t sizeNeeded)
	Ensure that the buffer is big enough and return a pointer to the start of the empty space in the buffer.
size_t	GetBufSize () const
	Returns the size of the buffer.
void *	GetData () const
	Return a pointer to the data in the buffer.
size_t	GetDataLen () const
	Returns the length of the valid data in the buffer.
void *	GetWriteBuf (size_t sizeNeeded)
	Ensure the buffer is big enough and return a pointer to the buffer which can be used to directly write into the buffer up to sizeNeeded bytes.
bool	IsEmpty () const
	Returns true if the buffer contains no data.
void	SetBufSize (size_t size)
	Ensures the buffer has at least size bytes available.
void	SetDataLen (size_t size)
	Sets the length of the data stored in the buffer.
void	UngetAppendBuf (size_t sizeUsed)
	Update the length after completing a direct append, which you must have used GetAppendBuf() to initialise.
void	UngetWriteBuf (size_t sizeUsed)
	Update the buffer after completing a direct write, which you must have used GetWriteBuf() to initialise.

Constructor & Destructor Documentation

wxMemoryBuffer::wxMemoryBuffer

(

const wxMemoryBuffer &

src

)

Copy constructor, refcounting is used for performance, but wxMemoryBuffer is not a copy-on-write structure so changes made to one buffer effect all copies made from it.

See Also

Reference Counting

wxMemoryBuffer::wxMemoryBuffer

(

size_t

size = 1024

)

Create a new buffer.

Parameters

size	size of the new buffer, 1KiB by default.

Member Function Documentation

void wxMemoryBuffer::AppendByte

(

char

data

)

Append a single byte to the buffer.

Parameters

data	New byte to append to the buffer.

void wxMemoryBuffer::AppendData	(	const void *	data,
		size_t	len
	)

Single call to append a data block to the buffer.

Parameters

data	Pointer to block to append to the buffer.
len	Length of data to append.

void wxMemoryBuffer::Clear

(

)

Clear the buffer contents.

The buffer won't contain any data after this method is called.

See Also

IsEmpty()

Since

2.9.4

void* wxMemoryBuffer::GetAppendBuf

(

size_t

sizeNeeded

)

Ensure that the buffer is big enough and return a pointer to the start of the empty space in the buffer.

This pointer can be used to directly write data into the buffer, this new data will be appended to the existing data.

Parameters

sizeNeeded

Amount of extra space required in the buffer for the append operation

size_t wxMemoryBuffer::GetBufSize

(

)

const

Returns the size of the buffer.

void* wxMemoryBuffer::GetData

(

)

const

Return a pointer to the data in the buffer.

size_t wxMemoryBuffer::GetDataLen

(

)

const

Returns the length of the valid data in the buffer.

void* wxMemoryBuffer::GetWriteBuf

(

size_t

sizeNeeded

)

Ensure the buffer is big enough and return a pointer to the buffer which can be used to directly write into the buffer up to sizeNeeded bytes.

bool wxMemoryBuffer::IsEmpty

(

)

const

Returns true if the buffer contains no data.

See Also

Clear()

Since

2.9.4

void wxMemoryBuffer::SetBufSize

(

size_t

size

)

Ensures the buffer has at least size bytes available.

void wxMemoryBuffer::SetDataLen

(

size_t

size

)

Sets the length of the data stored in the buffer.

Mainly useful for truncating existing data.

Parameters

size	New length of the valid data in the buffer. This is distinct from the allocated size

void wxMemoryBuffer::UngetAppendBuf

(

size_t

sizeUsed

)

Update the length after completing a direct append, which you must have used GetAppendBuf() to initialise.

Parameters

sizeUsed

This is the amount of new data that has been appended.

void wxMemoryBuffer::UngetWriteBuf

(

size_t

sizeUsed

)

Update the buffer after completing a direct write, which you must have used GetWriteBuf() to initialise.

Parameters

sizeUsed

The amount of data written in to buffer by the direct write