#include <MemoryMap.h>

Inheritance diagram for MemoryMap::NullBuffer:

Collaboration diagram for MemoryMap::NullBuffer:

Public Member Functions
virtual const void *	get_data_ptr () const
	Always returns the null pointer. More...

virtual BufferPtr	clone () const
	Create a new buffer from an existing buffer. More...

virtual size_t	read (void *, size_t offset, size_t nbytes) const
	Reads data from a buffer. More...

virtual size_t	write (const void *, size_t offset, size_t nbytes)
	Writes data into a buffer. More...

Public Member Functions inherited from MemoryMap::Buffer
virtual	~Buffer ()

virtual void	save (const std::string &filename) const
	Saves data to a file. More...

virtual bool	is_zero () const
	Returns true if the buffer's data is all zero. More...

virtual bool	is_read_only () const
	Property indicating whether buffer is read-only. More...

virtual void	set_read_only (bool b=true)
	Property indicating whether buffer is read-only. More...

void	clear_read_only ()
	Property indicating whether buffer is read-only. More...

virtual std::string	get_name () const
	Debug name for buffer. More...

virtual void	set_name (const std::string &s)
	Debug name for buffer. More...

virtual size_t	size () const
	Size of buffer in bytes. More...

virtual void	resize (size_t n)
	Size of buffer in bytes. More...

Static Public Member Functions
static BufferPtr	create (size_t size)
	Construct a new buffer. More...

Protected Member Functions
	NullBuffer (size_t size)

Protected Member Functions inherited from MemoryMap::Buffer
	Buffer (size_t size)

std::string	new_name ()

Additional Inherited Members
Protected Attributes inherited from MemoryMap::Buffer
bool	read_only
	If true, buffer data cannot be modified. More...

std::string	name
	Name for debugging. More...

size_t	p_size
	Size of buffer in bytes. More...

Detailed Description

Buffer that has no data.

This can be useful to reserve areas of the virtual memory address space without actually storing any data at them. All reads and writes using such a buffer will fail (return zero).

Definition at line 182 of file MemoryMap.h.

Constructor & Destructor Documentation

MemoryMap::NullBuffer::NullBuffer ( size_t size)

inlineprotected

Definition at line 195 of file MemoryMap.h.

Member Function Documentation

MemoryMap::BufferPtr MemoryMap::NullBuffer::create ( size_t size)

static

Construct a new buffer.

The buffer contains no data and all reads and writes will fail by returning zero.

Definition at line 151 of file MemoryMap.C.

Referenced by clone().

virtual const void* MemoryMap::NullBuffer::get_data_ptr ( ) const

inlinevirtual

Always returns the null pointer.

Implements MemoryMap::Buffer.

Definition at line 188 of file MemoryMap.h.

virtual BufferPtr MemoryMap::NullBuffer::clone ( ) const

inlinevirtual

Create a new buffer from an existing buffer.

The new buffer will point to a different copy of the data so that writing data into one buffer will not cause it to appear when reading from the other buffer. The type of the new buffer might not be the same as this buffer because not all buffers are able to copy their data. For instance, cloning an ExternBuffer or a MmapBuffer will create a ByteBuffer.

Implements MemoryMap::Buffer.

Definition at line 190 of file MemoryMap.h.

References create(), and MemoryMap::Buffer::size().

virtual size_t MemoryMap::NullBuffer::read	(	void *	buf,
		size_t	offset,
		size_t	nbytes
	)		const

inlinevirtual

Reads data from a buffer.

Reads up to nbytes of data from this buffer and copies it to the caller-supplied address, the buf argument. Reading starts at the specified byte offset from the beginning of this buffer. Returns the number of bytes copied. The output buffer is not zero-padded for short reads.

If buf is the null pointer, then no data is copied and the return value is the number of bytes that would have been copied if buf had not been null.

Implements MemoryMap::Buffer.

Definition at line 191 of file MemoryMap.h.

virtual size_t MemoryMap::NullBuffer::write	(	const void *	buf,
		size_t	offset,
		size_t	nbytes
	)

inlinevirtual

Writes data into a buffer.

Writes up to nbytes of data from buf into this buffer starting at the specified byte offset within this buffer. Returns the number of bytes written. The return value will be less than nbytes if an error occurs.

Implements MemoryMap::Buffer.

Definition at line 192 of file MemoryMap.h.

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

Public Member Functions

Static Public Member Functions

Protected Member Functions

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation