CXXR::MemoryBank Class Reference

Class to manage memory allocation and deallocation for CXXR. More...

#include <MemoryBank.hpp>

List of all members.

Static Public Member Functions
static void *	allocate (size_t bytes) throw (std::bad_alloc)
	Allocate a block of memory.
static size_t	blocksAllocated ()
	Number of blocks currently allocated.
static size_t	bytesAllocated ()
	Number of bytes currently allocated.
static void	check ()
	Integrity check.
static void	deallocate (void *p, size_t bytes)
	Deallocate a block.
static void	defragment ()
	Reorganise lists of free cells.

Friends
class	SchwarzCounter< MemoryBank >

---

Detailed Description

Class to manage memory allocation and deallocation for CXXR.

Small objects are quickly allocated from pools of various cell sizes; large objects are obtained directly from the main heap.

If the class is compiled with the FILL55 preprocessor variable defined, released memory blocks are filled with 0x55 bytes (though some of these may be overwritten by data used for free list management). This can be useful to show up premature deallocation of memory block, especially if used in conjunction with the CELLFIFO preprocessor variable documented in config.hpp .

---

Member Function Documentation

void * MemoryBank::allocate ( size_t  bytes ) throw (std::bad_alloc)

static

Allocate a block of memory.

Parameters:

bytes

Required size in bytes of the block.

Returns:

a pointer to the allocated cell.

Exceptions:

bad_alloc

if a cell cannot be allocated.

static size_t CXXR::MemoryBank::blocksAllocated ( )

inlinestatic

Number of blocks currently allocated.

Returns:

the number of blocks of memory currently allocated.

static size_t CXXR::MemoryBank::bytesAllocated ( )

inlinestatic

Number of bytes currently allocated.

Returns:

the number of bytes of memory currently allocated.

Note:

This refers to the total number of bytes requested in blocks that have been allocated but not subsequently deallocated. Actual utilisation of memory in the main heap may be greater than this, possibly by as much as a factor of 2.

void MemoryBank::check ( )

static

Integrity check.

Aborts the program with an error message if the class is found to be internally inconsistent.

static void CXXR::MemoryBank::deallocate ( void *  p, size_t  bytes  )

inlinestatic

Deallocate a block.

Parameters:

p	Pointer to a block of memory previously allocated by MemoryBank::allocate(), or a null pointer (in which case method does nothing).
bytes	The number of bytes in the memory block, i.e. the number of bytes requested in the corresponding call to allocate().

void MemoryBank::defragment ( )

static

Reorganise lists of free cells.

This is done with a view to increasing the probability that successive allocations will lie within the same cache line or (less importantly nowadays) memory page.

---

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

• MemoryBank.hpp ($Id: MemoryBank.hpp 1348 2013-02-25 17:49:03Z arr $)
• MemoryBank.cpp ($Id: MemoryBank.cpp 1348 2013-02-25 17:49:03Z arr $)