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].

   Classes
       struct _page

   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_tpagesize = 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
   virtual void* ost::MemPager::alloc (size_tsize) [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.

   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.

   void ost::MemPager::clean (void) [protected]
       Clean for memory cleanup before exiting.

   virtual void* ost::MemPager::first (size_tsize) [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.

   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.

   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.

       Reimplemented in ost::SharedMemPager, and ost::StackPager.

Friends And Related Function Documentation
   friend class MemPagerObject [friend]
   friend class String [friend]
Author
       Generated automatically by Doxygen for GNU CommonC++ from the source code.

GNU CommonC++							  Sat Jun 23 2012						  ost::MemPager(3)