.TH "ost::MemPager" 3 "Sun Dec 27 2020" "GNU CommonC++" \" -*- nroff -*-
.ad l
.nh
.SH 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\&.  

.SH SYNOPSIS
.br
.PP
.PP
\fC#include <misc\&.h>\fP
.PP
Inherited by \fBost::Keydata\fP\fC [protected]\fP, \fBost::SharedMemPager\fP, and \fBost::StackPager\fP\fC [protected]\fP\&.
.SS "Public Member Functions"

.in +1c
.ti -1c
.RI "int \fBgetPages\fP (void)"
.br
.RI "Return the total number of pages that have been allocated for this memory pool\&. "
.in -1c
.SS "Protected Member Functions"

.in +1c
.ti -1c
.RI "virtual void * \fBfirst\fP (size_t size)"
.br
.RI "Allocate first workspace from paged memory\&. "
.ti -1c
.RI "virtual void * \fBalloc\fP (size_t size)"
.br
.RI "Allocate memory from either the currently active page, or allocate a new page for the object\&. "
.ti -1c
.RI "char * \fBfirst\fP (char *str)"
.br
.RI "Allocate a string from the memory pager pool and copy the string into it's new memory area\&. "
.ti -1c
.RI "char * \fBalloc\fP (const char *str)"
.br
.RI "Allocate a string from the memory pager pool and copy the string inti it's new memory area\&. "
.ti -1c
.RI "\fBMemPager\fP (size_t pagesize=4096)"
.br
.RI "Create a paged memory pool for cumulative storage\&. "
.ti -1c
.RI "void \fBpurge\fP (void)"
.br
.RI "purge the current memory pool\&. "
.ti -1c
.RI "void \fBclean\fP (void)"
.br
.RI "Clean for memory cleanup before exiting\&. "
.ti -1c
.RI "virtual \fB~MemPager\fP ()"
.br
.RI "Delete the memory pool and all allocated memory\&. "
.in -1c
.SS "Friends"

.in +1c
.ti -1c
.RI "class \fBString\fP"
.br
.ti -1c
.RI "class \fBMemPagerObject\fP"
.br
.in -1c
.SH "Detailed Description"
.PP 
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\&.
.PP
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++\&.
.PP
\fBAuthor\fP
.RS 4
David Sugar dyfet@ostel.com
.RE
.PP
Accumulative object memory allocator\&. 
.SH "Constructor & Destructor Documentation"
.PP 
.SS "ost::MemPager::MemPager (size_t pagesize = \fC4096\fP)\fC [protected]\fP"

.PP
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\&.
.PP
\fBParameters\fP
.RS 4
\fIpagesize\fP page size to allocate chunks\&. 
.RE
.PP

.SS "virtual ost::MemPager::~MemPager ()\fC [protected]\fP, \fC [virtual]\fP"

.PP
Delete the memory pool and all allocated memory\&. 
.SH "Member Function Documentation"
.PP 
.SS "char* ost::MemPager::alloc (const char * str)\fC [protected]\fP"

.PP
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\&.
.PP
\fBParameters\fP
.RS 4
\fIstr\fP string to allocate and copy into paged memory pool\&. 
.RE
.PP
\fBReturns\fP
.RS 4
copy of string from allocated memory\&. 
.RE
.PP

.SS "virtual void* ost::MemPager::alloc (size_t size)\fC [protected]\fP, \fC [virtual]\fP"

.PP
Allocate memory from either the currently active page, or allocate a new page for the object\&. 
.PP
\fBParameters\fP
.RS 4
\fIsize\fP size of memory to allocate\&. 
.RE
.PP
\fBReturns\fP
.RS 4
pointer to allocated memory\&. 
.RE
.PP

.PP
Reimplemented in \fBost::SharedMemPager\fP\&.
.SS "void ost::MemPager::clean (void)\fC [protected]\fP"

.PP
Clean for memory cleanup before exiting\&. 
.SS "char* ost::MemPager::first (char * str)\fC [protected]\fP"

.PP
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\&.
.PP
\fBParameters\fP
.RS 4
\fIstr\fP string to allocate and copy into paged memory pool\&. 
.RE
.PP
\fBReturns\fP
.RS 4
copy of string from allocated memory\&. 
.RE
.PP

.SS "virtual void* ost::MemPager::first (size_t size)\fC [protected]\fP, \fC [virtual]\fP"

.PP
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\&.
.PP
\fBParameters\fP
.RS 4
\fIsize\fP size of memory to allocate\&. 
.RE
.PP
\fBReturns\fP
.RS 4
pointer to allocated memory\&. 
.RE
.PP

.PP
Reimplemented in \fBost::SharedMemPager\fP\&.
.SS "int ost::MemPager::getPages (void)\fC [inline]\fP"

.PP
Return the total number of pages that have been allocated for this memory pool\&. 
.PP
\fBReturns\fP
.RS 4
number of pages allocated\&. 
.RE
.PP

.SS "void ost::MemPager::purge (void)\fC [protected]\fP"

.PP
purge the current memory pool\&. 
.SH "Friends And Related Function Documentation"
.PP 
.SS "friend class \fBMemPagerObject\fP\fC [friend]\fP"

.SS "friend class \fBString\fP\fC [friend]\fP"


.SH "Author"
.PP 
Generated automatically by Doxygen for GNU CommonC++ from the source code\&.