Version: 3.1.1
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. More...
 
 wxMemoryBuffer (size_t size=1024)
 Create a new buffer. More...
 
void AppendByte (char data)
 Append a single byte to the buffer. More...
 
void AppendData (const void *data, size_t len)
 Single call to append a data block to the buffer. More...
 
void Clear ()
 Clear the buffer contents. More...
 
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. More...
 
size_t GetBufSize () const
 Returns the size of the buffer. More...
 
void * GetData () const
 Return a pointer to the data in the buffer. More...
 
size_t GetDataLen () const
 Returns the length of the valid data in the buffer. More...
 
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. More...
 
bool IsEmpty () const
 Returns true if the buffer contains no data. More...
 
void SetBufSize (size_t size)
 Ensures the buffer has at least size bytes available. More...
 
void SetDataLen (size_t size)
 Sets the length of the data stored in the buffer. More...
 
void UngetAppendBuf (size_t sizeUsed)
 Update the length after completing a direct append, which you must have used GetAppendBuf() to initialise. More...
 
void UngetWriteBuf (size_t sizeUsed)
 Update the buffer after completing a direct write, which you must have used GetWriteBuf() to initialise. More...
 

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
sizesize of the new buffer, 1KiB by default.

Member Function Documentation

void wxMemoryBuffer::AppendByte ( char  data)

Append a single byte to the buffer.

Parameters
dataNew 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
dataPointer to block to append to the buffer.
lenLength 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
sizeNeededAmount 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
sizeNew 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
sizeUsedThis 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
sizeUsedThe amount of data written in to buffer by the direct write