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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. Accumulative object memory allocator. More...

#include <misc.h>

Inheritance diagram for MemPager::

List of all members.

Public Methods
int	getPages (void)
	Return the total number of pages that have been allocated for this memory pool. More...
Protected Methods
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 (char *str)
	Allocate a string from the memory pager pool and copy the string inti it's new memory area. More...
	MemPager (int pagesize=4096)
	Create a paged memory pool for cumulative storage. More...
void	purge (void)
	purge the current memory pool. More...
virtual	~MemPager ()
	Delete the memory pool and all allocated memory. More...

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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. Accumulative object memory allocator.

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@ostel.com>

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Constructor & Destructor Documentation

MemPager::MemPager (  int   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   to allocate chunks.

virtual MemPager::~MemPager (    )  [protected, virtual]

Delete the memory pool and all allocated memory.

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Member Function Documentation

char* MemPager::alloc (  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   to allocate and copy into paged memory pool. Returns: copy of string from allocated memory.

virtual void* MemPager::alloc (  size_t   size )  [protected, virtual]

Allocate memory from either the currently active page, or allocate a new page for the object. Parameters: 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   to allocate and copy into paged memory pool. Returns: copy of string from allocated memory.

virtual void* MemPager::first (  size_t   size )  [protected, virtual]

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   of memory to allocate. Returns: pointer to allocated memory. Reimplemented in SharedMemPager.

int MemPager::getPages (  void   )  [inline]

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

void MemPager::purge (  void   )  [protected]

purge the current memory pool. Reimplemented in SharedMemPager.

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

• misc.h

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