MemPager Class Reference

The memory pager is used to allocate cumulative memory pages for storing object specific "persistant" data that is presumed to persist during the life of a given derived object. More...

#include <misc.h>

Inheritance diagram for MemPager:

Collaboration diagram for MemPager:

Data Structures
struct	_page

Public Member Functions
int	getPages (void)
	Return the total number of pages that have been allocated for this memory pool. More...

Protected Member Functions
virtual void *	first (size_t size)
	Allocate first workspace from paged memory. More...
virtual void *	alloc (size_t size)
	Allocate memory from either the currently active page, or allocate a new page for the object. More...
char *	first (char *str)
	Allocate a string from the memory pager pool and copy the string into it's new memory area. More...
char *	alloc (const char *str)
	Allocate a string from the memory pager pool and copy the string inti it's new memory area. More...
	MemPager (size_t pagesize=4096)
	Create a paged memory pool for cumulative storage. More...
void	purge (void)
	purge the current memory pool. More...
void	clean (void)
	Clean for memory cleanup before exiting. More...
virtual	~MemPager ()
	Delete the memory pool and all allocated memory. More...

Private Attributes
size_t	pagesize
unsigned int	pages
struct MemPager::_page *	page

Friends
class	String
class	MemPagerObject

Detailed Description

The memory pager is used to allocate cumulative memory pages for storing object specific "persistant" data that is presumed to persist during the life of a given derived object.

When the object is destroyed, all accumulated data is automatically purged.

There are a number of odd and specialized utility classes found in Common C++. The most common of these is the "MemPager" class. This is basically a class to enable page-grouped "cumulative" memory allocation; all accumulated allocations are dropped during the destructor. This class has found it's way in a lot of other utility classes in Common C++.

Author

David Sugar dyfet.nosp@m.@ost.nosp@m.el.co.nosp@m.m Accumulative object memory allocator.

Definition at line 91 of file misc.h.

Constructor & Destructor Documentation

MemPager::MemPager ( size_t  pagesize = 4096 )

protected

Create a paged memory pool for cumulative storage.

This pool allocates memory in fixed "pagesize" chunks. Ideal performance is achived when the pool size matches the system page size. This pool can only exist in derived objects.

Parameters

pagesize

page size to allocate chunks.

virtual MemPager::~MemPager ( )

protectedvirtual

Delete the memory pool and all allocated memory.

Member Function Documentation

virtual void* MemPager::alloc ( size_t  size )

protectedvirtual

Allocate memory from either the currently active page, or allocate a new page for the object.

Parameters

size	size of memory to allocate.

Returns

pointer to allocated memory.

Reimplemented in SharedMemPager.

char* MemPager::alloc ( const char *  str )

protected

Allocate a string from the memory pager pool and copy the string inti it's new memory area.

This checks only the last active page for available space before allocating a new page.

Parameters

str	string to allocate and copy into paged memory pool.

Returns

copy of string from allocated memory.

void MemPager::clean ( void  )

protected

Clean for memory cleanup before exiting.

virtual void* MemPager::first ( size_t  size )

protectedvirtual

Allocate first workspace from paged memory.

This method scans all currently allocated blocks for available space before adding new pages and hence is both slower and more efficient.

Parameters

size	size of memory to allocate.

Returns

pointer to allocated memory.

Reimplemented in SharedMemPager.

char* MemPager::first ( char *  str )

protected

Allocate a string from the memory pager pool and copy the string into it's new memory area.

This method allocates memory by first searching for an available page, and then allocating a new page if no space is found.

Parameters

str	string to allocate and copy into paged memory pool.

Returns

copy of string from allocated memory.

int MemPager::getPages ( void  )

inline

Return the total number of pages that have been allocated for this memory pool.

Returns

number of pages allocated.

Definition at line 181 of file misc.h.

void MemPager::purge ( void  )

protected

purge the current memory pool.

Friends And Related Function Documentation

friend class MemPagerObject

friend

Definition at line 95 of file misc.h.

friend class String

friend

Definition at line 94 of file misc.h.

Field Documentation

struct MemPager::_page * MemPager::page

private

unsigned int MemPager::pages

private

Definition at line 98 of file misc.h.

size_t MemPager::pagesize

private

Definition at line 97 of file misc.h.

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

• misc.h