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ost::MemPager(3) Library Functions Manual ost::MemPager(3)

NAME

ost::MemPager - 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.

SYNOPSIS

#include <misc.h>

Inherited by ost::Keydata [protected], ost::SharedMemPager, and ost::StackPager [protected].

Public Member Functions


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

Protected Member Functions


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

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@ostel.com

Accumulative object memory allocator.

Constructor & Destructor Documentation

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

Delete the memory pool and all allocated memory.

Member Function Documentation

char* ost::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.

virtual void* ost::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 size of memory to allocate.

Returns

pointer to allocated memory.

Reimplemented in ost::SharedMemPager.

void ost::MemPager::clean (void) [protected]

Clean for memory cleanup before exiting.

char* ost::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.

virtual void* ost::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 size of memory to allocate.

Returns

pointer to allocated memory.

Reimplemented in ost::SharedMemPager.

int ost::MemPager::getPages (void) [inline]

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

Returns

number of pages allocated.

void ost::MemPager::purge (void) [protected]

purge the current memory pool.

Friends And Related Function Documentation

friend class MemPagerObject [friend]

friend class String [friend]

Author

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Sun Dec 27 2020 GNU CommonC++