\section{ost::Mem\-Pager Class Reference}
\label{classost_1_1_mem_pager}\index{ost::MemPager@{ost::MemPager}}
The memory pager is used to allocate cumulative memory pages for storing object specific \char`\"{}persistant\char`\"{} data that is presumed to persist during the life of a given derived object.Accumulative object memory allocator.  


{\tt \#include $<$misc.h$>$}

Inheritance diagram for ost::Mem\-Pager::\begin{figure}[H]
\begin{center}
\leavevmode
\includegraphics[height=2cm]{classost_1_1_mem_pager}
\end{center}
\end{figure}
\subsection*{Public Member Functions}
\begin{CompactItemize}
\item 
int {\bf get\-Pages} (void)
\begin{CompactList}\small\item\em Return the total number of pages that have been allocated for this memory pool. \item\end{CompactList}\end{CompactItemize}
\subsection*{Protected Member Functions}
\begin{CompactItemize}
\item 
virtual void $\ast$ {\bf first} (size\_\-t size)
\begin{CompactList}\small\item\em Allocate first workspace from paged memory. \item\end{CompactList}\item 
virtual void $\ast$ {\bf alloc} (size\_\-t size)
\begin{CompactList}\small\item\em Allocate memory from either the currently active page, or allocate a new page for the object. \item\end{CompactList}\item 
char $\ast$ {\bf first} (char $\ast$str)
\begin{CompactList}\small\item\em Allocate a string from the memory pager pool and copy the string into it's new memory area. \item\end{CompactList}\item 
char $\ast$ {\bf alloc} (const char $\ast$str)
\begin{CompactList}\small\item\em Allocate a string from the memory pager pool and copy the string inti it's new memory area. \item\end{CompactList}\item 
{\bf Mem\-Pager} (size\_\-t pagesize=4096)
\begin{CompactList}\small\item\em Create a paged memory pool for cumulative storage. \item\end{CompactList}\item 
void {\bf purge} (void)
\begin{CompactList}\small\item\em purge the current memory pool. \item\end{CompactList}\item 
virtual {\bf $\sim$Mem\-Pager} ()
\begin{CompactList}\small\item\em Delete the memory pool and all allocated memory. \item\end{CompactList}\end{CompactItemize}
\subsection*{Friends}
\begin{CompactItemize}
\item 
class {\bf String}
\item 
class {\bf Mem\-Pager\-Object}
\end{CompactItemize}
\subsection*{Classes}
\begin{CompactItemize}
\item 
struct {\bf \_\-page}
\end{CompactItemize}


\subsection{Detailed Description}
The memory pager is used to allocate cumulative memory pages for storing object specific \char`\"{}persistant\char`\"{} 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 \char`\"{}Mem\-Pager\char`\"{} class. This is basically a class to enable page-grouped \char`\"{}cumulative\char`\"{} 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++.

\begin{Desc}
\item[Author:]David Sugar $<${\tt dyfet@ostel.com}$>$ \end{Desc}




\subsection{Constructor \& Destructor Documentation}
\index{ost::MemPager@{ost::Mem\-Pager}!MemPager@{MemPager}}
\index{MemPager@{MemPager}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}ost::Mem\-Pager::Mem\-Pager (size\_\-t {\em pagesize} = {\tt 4096})\hspace{0.3cm}{\tt  [protected]}}\label{classost_1_1_mem_pager_5dc37c26af34d6f4c26e125eded3e2be}


Create a paged memory pool for cumulative storage. 

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

\begin{Desc}
\item[Parameters:]
\begin{description}
\item[{\em pagesize}]page size to allocate chunks. \end{description}
\end{Desc}
\index{ost::MemPager@{ost::Mem\-Pager}!~MemPager@{$\sim$MemPager}}
\index{~MemPager@{$\sim$MemPager}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}virtual ost::Mem\-Pager::$\sim$Mem\-Pager ()\hspace{0.3cm}{\tt  [protected, virtual]}}\label{classost_1_1_mem_pager_58dcf48146eca4ae2286706968fdf9c5}


Delete the memory pool and all allocated memory. 



\subsection{Member Function Documentation}
\index{ost::MemPager@{ost::Mem\-Pager}!alloc@{alloc}}
\index{alloc@{alloc}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}char$\ast$ ost::Mem\-Pager::alloc (const char $\ast$ {\em str})\hspace{0.3cm}{\tt  [protected]}}\label{classost_1_1_mem_pager_245b6c4181ccccbabc52f1c3451f2fb6}


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.

\begin{Desc}
\item[Parameters:]
\begin{description}
\item[{\em str}]string to allocate and copy into paged memory pool. \end{description}
\end{Desc}
\begin{Desc}
\item[Returns:]copy of string from allocated memory. \end{Desc}
\index{ost::MemPager@{ost::Mem\-Pager}!alloc@{alloc}}
\index{alloc@{alloc}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}virtual void$\ast$ ost::Mem\-Pager::alloc (size\_\-t {\em size})\hspace{0.3cm}{\tt  [protected, virtual]}}\label{classost_1_1_mem_pager_3a03cb50bd4084ddbf6314ec0339d176}


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

\begin{Desc}
\item[Parameters:]
\begin{description}
\item[{\em size}]size of memory to allocate. \end{description}
\end{Desc}
\begin{Desc}
\item[Returns:]pointer to allocated memory. \end{Desc}


Reimplemented in {\bf ost::Shared\-Mem\-Pager} {\rm (p.\,\pageref{classost_1_1_shared_mem_pager_d5c3aad294fd247a972a72983dcf831b})}.\index{ost::MemPager@{ost::Mem\-Pager}!first@{first}}
\index{first@{first}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}char$\ast$ ost::Mem\-Pager::first (char $\ast$ {\em str})\hspace{0.3cm}{\tt  [protected]}}\label{classost_1_1_mem_pager_7ea4e6f82bffa66c994fcd10ebdee594}


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.

\begin{Desc}
\item[Parameters:]
\begin{description}
\item[{\em str}]string to allocate and copy into paged memory pool. \end{description}
\end{Desc}
\begin{Desc}
\item[Returns:]copy of string from allocated memory. \end{Desc}
\index{ost::MemPager@{ost::Mem\-Pager}!first@{first}}
\index{first@{first}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}virtual void$\ast$ ost::Mem\-Pager::first (size\_\-t {\em size})\hspace{0.3cm}{\tt  [protected, virtual]}}\label{classost_1_1_mem_pager_2c82ac4c97fcba81c643966973e78d84}


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.

\begin{Desc}
\item[Parameters:]
\begin{description}
\item[{\em size}]size of memory to allocate. \end{description}
\end{Desc}
\begin{Desc}
\item[Returns:]pointer to allocated memory. \end{Desc}


Reimplemented in {\bf ost::Shared\-Mem\-Pager} {\rm (p.\,\pageref{classost_1_1_shared_mem_pager_644a00d48052aff83a180523b205aa6f})}.\index{ost::MemPager@{ost::Mem\-Pager}!getPages@{getPages}}
\index{getPages@{getPages}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}int ost::Mem\-Pager::get\-Pages (void)\hspace{0.3cm}{\tt  [inline]}}\label{classost_1_1_mem_pager_320897ecfca3e92378c45ec70aee58ba}


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

\begin{Desc}
\item[Returns:]number of pages allocated. \end{Desc}
\index{ost::MemPager@{ost::Mem\-Pager}!purge@{purge}}
\index{purge@{purge}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}void ost::Mem\-Pager::purge (void)\hspace{0.3cm}{\tt  [protected]}}\label{classost_1_1_mem_pager_5bfdb6f2d6f569ba08c32c59efb3a012}


purge the current memory pool. 



Reimplemented in {\bf ost::Stack\-Pager} {\rm (p.\,\pageref{classost_1_1_stack_pager_c903c181770651ee8f42717892dd9fa4})}, and {\bf ost::Shared\-Mem\-Pager} {\rm (p.\,\pageref{classost_1_1_shared_mem_pager_fafb0b8ce31a2b1fdee64a5a9cadebc6})}.

\subsection{Friends And Related Function Documentation}
\index{ost::MemPager@{ost::Mem\-Pager}!MemPagerObject@{MemPagerObject}}
\index{MemPagerObject@{MemPagerObject}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}friend class {\bf Mem\-Pager\-Object}\hspace{0.3cm}{\tt  [friend]}}\label{classost_1_1_mem_pager_c5ec8bc6fca4e4e6a8faa45d4b0a9d58}


\index{ost::MemPager@{ost::Mem\-Pager}!String@{String}}
\index{String@{String}!ost::MemPager@{ost::Mem\-Pager}}
\subsubsection{\setlength{\rightskip}{0pt plus 5cm}friend class {\bf String}\hspace{0.3cm}{\tt  [friend]}}\label{classost_1_1_mem_pager_7fb804f7dc96dd9f705c84095f37f1ca}




The documentation for this class was generated from the following file:\begin{CompactItemize}
\item 
{\bf misc.h}\end{CompactItemize}