An encapsulation of a block of memory that can be mapped by one or more (not necessarily related) processes; when one process changes the data in the block, the changes are immediately visible to the other processes. More...

#include <SharedMemoryBlock.h++>

Inheritance diagram for SharedMemoryBlock:

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Collaboration diagram for SharedMemoryBlock:

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Public Member Functions
	SharedMemoryBlock (const String &name, size_t size, const Permissions &perm=Permissions::USER_READ_WRITE)
	Construct a new SharedMemoryBlock. More...

	~SharedMemoryBlock ()
	Destructor. More...

void	attach (bool readOnly=false)
	Attach to the memory block, creating it if it does not yet exist. More...

void	detach ()
	Detach from the memory block, and destroy it if no other process currently has it mapped. More...

virtual void	setBase (byte_t *base)
	Overridden to have no effect. More...

virtual void	setSize (size_t size)
	Overridden to have no effect. More...

String	getName () const
	Get the name of the memory block. More...

void	zero ()
	Zero the memory block. More...

void	fill (byte_t value)
	Fill the memory block with the given byte value. More...

byte_t *	getBase ()
	Get a pointer to the beginning of the memory block. More...

const byte_t *	getBase () const
	Get a pointer to the beginning of the memory block. More...

size_t	getSize () const
	Get the size of the memory block. More...

bool	operator== (const MemoryBlock &other) const
	Equality operator. More...

bool	operator!= (const MemoryBlock &other) const
	Inequality operator. More...

byte_t	operator[] (int index) const
	Bounds-checked access. More...

byte_t &	operator[] (int index)
	Bounds-checked access. More...

bool	copyFrom (const MemoryBlock &other)
	Copy data from another memory block to this one. More...

void	moveFrom (MemoryBlock &other)
	Copy data from another (possibly overlapping) memory block to this one. More...

int	indexOf (byte_t val, uint_t startIndex=0) const
	Find the first occurrence of a given byte value in the memory block, starting at a given index. More...

bool	operator! () const
	Test if the base of the block is NULL. More...

Protected Attributes
byte_t *	_base
	A pointer to the beginning of the memory block. More...

size_t	_size
	The size of the memory block, in bytes. More...

Detailed Description

An encapsulation of a block of memory that can be mapped by one or more (not necessarily related) processes; when one process changes the data in the block, the changes are immediately visible to the other processes.

Author: Mark Lindner

Constructor & Destructor Documentation

◆ SharedMemoryBlock()

SharedMemoryBlock	(	const String &	name,
		size_t	size,
		const Permissions &	perm = `Permissions::USER_READ_WRITE`
	)

Construct a new SharedMemoryBlock.

The actual memory segment is not created and mapped until a call to attach() is made.

Parameters

name	The name of the memory block. For maximal portability, the name should consist of at most 14 alphanumeric characters and should not contain slashes.
size	The size of the memory block, in bytes. This size will be rounded up to the nearest multiple of the system page size.
perm	The permissions with which to create the memory block, if it does not exist at the time of the attach().

◆ ~SharedMemoryBlock()

~SharedMemoryBlock ( )

Destructor.

Detaches from the memory block.

Member Function Documentation

◆ attach()

void attach ( bool readOnly = false )

Attach to the memory block, creating it if it does not yet exist.

Parameters

readOnly A flag indicating whether the memory block should be mapped for read-only access or read-write access.

Exceptions

SystemException If the operation fails.

◆ copyFrom()

bool copyFrom ( const MemoryBlock & other )

inherited

Copy data from another memory block to this one.

The number of bytes copied is the minimum of the sizes of the two blocks. The blocks may not overlap.

Parameters

other The block to copy from.

Returns: true if the copy succeeded, false if the blocks overlap.

◆ detach()

void detach ( )

Detach from the memory block, and destroy it if no other process currently has it mapped.

◆ fill()

void fill ( byte_t value )

inherited

Fill the memory block with the given byte value.

◆ getBase() [1/2]

byte_t* getBase ( )

inlineinherited

Get a pointer to the beginning of the memory block.

◆ getBase() [2/2]

const byte_t* getBase ( ) const

inlineinherited

Get a pointer to the beginning of the memory block.

◆ getName()

String getName ( ) const

inline

Get the name of the memory block.

◆ getSize()

size_t getSize ( ) const

inlineinherited

Get the size of the memory block.

◆ indexOf()

int indexOf	(	byte_t	val,
		uint_t	startIndex = `0`
	)		const

inherited

Find the first occurrence of a given byte value in the memory block, starting at a given index.

Parameters

val	The value to search for.
startIndex	The index to begin searching at.

Returns: The index of the first matching value, or -1 if not found.

◆ moveFrom()

void moveFrom ( MemoryBlock & other )

inherited

Copy data from another (possibly overlapping) memory block to this one.

The number of bytes copied is the minimum of the sizes of the two blocks.

Parameters

other The block to copy from. Note that the copy may result in both blocks being modified, if the source area overlaps the target area.

◆ operator!()

bool operator! ( ) const

inlineinherited

Test if the base of the block is NULL.

◆ operator!=()

bool operator!= ( const MemoryBlock & other ) const

inlineinherited

Inequality operator.

◆ operator==()

bool operator== ( const MemoryBlock & other ) const

inherited

Equality operator.

◆ operator[]() [1/2]

byte_t operator[] ( int index ) const

inherited

Bounds-checked access.

Exceptions

OutOfBoundsException If the index is out of bounds.

◆ operator[]() [2/2]

byte_t & operator[] ( int index )

inherited

Bounds-checked access.

Exceptions

OutOfBoundsException If the index is out of bounds.

◆ setBase()

void setBase ( byte_t * base )

virtual

Overridden to have no effect.

Reimplemented from MemoryBlock.

◆ setSize()

void setSize ( size_t size )

virtual

Overridden to have no effect.

◆ zero()

void zero ( )

inlineinherited

Zero the memory block.

Member Data Documentation

◆ _base

byte_t* _base

protectedinherited

A pointer to the beginning of the memory block.

◆ _size

size_t _size

protectedinherited

The size of the memory block, in bytes.

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

Public Member Functions

Protected Attributes

Detailed Description

Constructor & Destructor Documentation

◆ SharedMemoryBlock()

◆ ~SharedMemoryBlock()

Member Function Documentation

◆ attach()

◆ copyFrom()

◆ detach()

◆ fill()

◆ getBase() [1/2]

◆ getBase() [2/2]

◆ getName()

◆ getSize()

◆ indexOf()

◆ moveFrom()

◆ operator!()

◆ operator!=()

◆ operator==()

◆ operator[]() [1/2]

◆ operator[]() [2/2]

◆ setBase()

◆ setSize()

◆ zero()

Member Data Documentation

◆ _base

◆ _size