Source code of Windows XP (NT5)
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// Copyright (C) 1997 Microsoft Corporation. All rights reserved.
#if _MSC_VER > 1000
#pragma once
#endif
#ifndef __SUBFILE_H__
#define __SUBFILE_H__
#include "hhtypes.h"
// we have three possible caching schemes:
// HH_FAST_CACHE - fast but its a hog!
//
// We store a small number of pages (2-3) for each unique
// title and subfile combination. This results is quite of bit
// of memory being used per collection but oh boy is it fast!
//
//#define HH_FAST_CACHE
// HH_EFFICIENT_CACHE - slow but it saves memory!
//
// We store a small number of moderate pages (2-3) for each unique
// subfile regardless of the title it came from. This results in an
// efficient use of memory since like subfiles, such as #TOCIDX, share
// the same group of cache pages instead of having their own uniqe group
// per title. However, this method slows things down since multiple reads
// from the same named subfile accross several titles results in many
// cache misses.
//
//#define HH_EFFICIENT_CACHE
// HH_SHARED_CACHE - nice balance of speed and size!
//
// We store a large number of pages (16+) for the entire collection.
// This result is a fixed quantity of cache pages regardless of number
// and type of subfiles we have. It utilizes memory well since we can
// access multiple subfiles of the same name accross several titles
// effectively yielding a larger pool of cache pages.
//
// [paulti] - We want to use this method exclusively. Please see me
// if you want to change this for any reason.
//
#define HH_SHARED_CACHE
#if defined ( HH_FAST_CACHE )
#define CACHE_PAGE_COUNT 3
#elif defined ( HH_EFFICIENT_CACHE )
#define CACHE_PAGE_COUNT 5
#else // HH_SHARED_CACHE
#define CACHE_PAGE_COUNT 32
#endif
class CSubFileSystem;
class CExTitle;
typedef struct page {
CExTitle* pTitle;
DWORD dwPage;
HASH hashPathname;
DWORD dwLRU;
BYTE rgb[PAGE_SIZE];
} PAGE;
//////////////////////////////////////////////
//
// CPagesList
//
//////////////////////////////////////////////
class CPagesList
{
friend class CPagedSubfile;
friend class CPages;
public:
CPagesList() { m_pFirst = 0; }
~CPagesList();
private:
CPages* m_pFirst;
CPages* GetPages( HASH );
};
////////////////////////////////////////
//
// CPages
//
////////////////////////////////////////
class CPages
{
public:
void Flush( CExTitle* pTitle );
private:
CPages( HASH );
void* Find( const CExTitle *, HASH, DWORD );
void* Alloc( CExTitle *, HASH, DWORD );
void Flush( void );
CPages* m_pNext;
HASH m_hash;
DWORD m_dwLRUPage;
DWORD m_dwLRUCount;
PAGE m_pages[CACHE_PAGE_COUNT];
friend class CPagedSubfile;
friend class CPagesList;
};
//////////////////////////////////////////////
//
// CPagedSubfile
//
//////////////////////////////////////////////
class CPagedSubfile
{
public:
CPagedSubfile();
~CPagedSubfile();
HRESULT Open(CExTitle *, LPCSTR);
void* Offset(DWORD dwOffs);
void* Page(DWORD iPage);
private:
CSubFileSystem* m_pCSubFileSystem;
CExTitle* m_pTitle;
HASH m_hashPathname;
HASH m_hash;
DWORD m_cbSize;
CPages* m_pPages;
};
#endif