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/*++
Copyright (C) 1997-2000 Microsoft Corporation
Module Name:
MMFARENA.H
Abstract:
CArena derivative based on memory mapped files.
History:
a-raymcc 23-Apr-96 Created
paulall 23-Mar-98 Re-worked
--*/
#ifndef _MMFARENA_H_
#define _MMFARENA_H_
#include "corepol.h"
#include "FlexArry.h"
#if defined _WIN32
#define MMF_DELETED_MASK 0x80000000
#define MMF_REMOVE_DELETED_MASK 0x7FFFFFFF
#define MMF_DEBUG_DELETED_TAG 0xFFFFFFFF
#define MMF_DEBUG_INUSE_TAG 0xFEFEFEFE
#elif defined _WIN64
#define MMF_DELETED_MASK 0x8000000000000000
#define MMF_REMOVE_DELETED_MASK 0x7FFFFFFFFFFFFFFF
#define MMF_DEBUG_DELETED_TAG 0xFFFFFFFFFFFFFFFF
#define MMF_DEBUG_INUSE_TAG 0xFEFEFEFEFEFEFEFE
#endif
struct MMFOffsetItem;
#include "corex.h"
class DATABASE_FULL_EXCEPTION : public CX_Exception
{
};
//***************************************************************************
//
// struct MMF_ARENA_HEADER
//
// Root structure for MMF Arena. This is recorded on the disk
// image at the very beginning of the file.
//
//***************************************************************************
#pragma pack(4) // Require fixed aligment.
typedef struct
{
// Version used to create file
// vvvvvv MUST BE FIRST VALUE vvvvvvv
DWORD m_dwVersion; // <<<<<< MUST BE FIRST VALUE!
// ^^^^^^ MUST BE FIRST VALUE ^^^^^^^
DWORD m_dwGranularity; // Granularity of allocation
DWORD m_dwCurrentSize; // Current size of heap
DWORD m_dwMaxSize; // Max heap size, -1= no limit
DWORD m_dwGrowBy; // Bytes to grow by during out-of-heap
DWORD_PTR m_dwHeapExtent; // First unused address
DWORD_PTR m_dwEndOfHeap; // Last valid address + 1
DWORD_PTR m_dwFreeList; // NULL if empty
DWORD_PTR m_dwRootBlock; // Root block
DWORD m_dwSizeOfFirstPage; //Size of the first block
} MMF_ARENA_HEADER;
typedef struct
{
DWORD m_dwSize; //Size of block. Highest bit set when deleted.
} MMF_BLOCK_HEADER;
typedef struct
{
DWORD_PTR m_dwFLback; //previous free block in the chain, NULL if not deleted
DWORD m_dwCheckBlock[2];
} MMF_BLOCK_TRAILER;
typedef struct
{
DWORD_PTR m_dwFLnext; //Next free block in the chain
} MMF_BLOCK_DELETED;
typedef struct
{
DWORD m_dwSize; //Size of page
} MMF_PAGE_HEADER; //Page header... not there for first page.
#pragma pack() // Restore previous aligment.
//***************************************************************************
//
// class CMMFArena2
//
// Implements an offset-based heap over a memory-mapped file.
//
//***************************************************************************
class CMMFArena2
{
DWORD m_dwStatus;
HANDLE m_hFile;
MMF_ARENA_HEADER *m_pHeapDescriptor;
DWORD m_dwCursor;
DWORD m_dwMappingGranularity;
bool m_bReadOnlyAccess;
DWORD m_dwMaxPageSize;
CFlexArray m_OffsetManager;
//Adds the header and trailer items to the specified block.
BOOL DecorateUsedBlock(DWORD_PTR dwBlock, DWORD dwBytes);
//Adds header and trailer items to the specified block and marks it as deleted
BOOL DecorateAsDeleted(DWORD_PTR dwBlock,
DWORD dwBytes,
DWORD_PTR dwNextFreeListOffset,
DWORD_PTR dwPrevFreeListOffset);
//Retrieves the size of the block from the header and removes the deleted bit
DWORD GetSize(MMF_BLOCK_HEADER *pBlock) { return pBlock->m_dwSize & MMF_REMOVE_DELETED_MASK; }
MMF_BLOCK_DELETED *GetUserBlock(MMF_BLOCK_HEADER *pBlockHeader) { return (MMF_BLOCK_DELETED*)(LPBYTE(pBlockHeader) + sizeof(MMF_BLOCK_HEADER)); }
MMF_BLOCK_TRAILER *GetTrailerBlock(MMF_BLOCK_HEADER *pBlockHeader) { return (MMF_BLOCK_TRAILER*)(LPBYTE(pBlockHeader) + GetSize(pBlockHeader) - sizeof(MMF_BLOCK_TRAILER)); }
//Removes a deleted block from the free-list
BOOL RemoveBlockFromFreeList(MMF_BLOCK_HEADER *pBlock);
//Gets the previous block pointer if the block is deleted, otherwise return NULL
MMF_BLOCK_HEADER *GetPreviousDeletedBlock(MMF_BLOCK_HEADER *pBlockHeader);
//Zero's out a block (not including the header and trailer!)
BOOL ZeroOutBlock(DWORD_PTR dwBlock, int cFill)
#if (defined DEBUG || defined _DEBUG)
;
#else
{ return TRUE;}
#endif
//Some debugging functions...
void Reset();
BOOL Next(LPBYTE *ppAddress, DWORD *pdwSize, BOOL *pbActive);
//Checks the deleted bit of the size block
BOOL IsDeleted(MMF_BLOCK_HEADER *pBlock) { return (pBlock->m_dwSize & MMF_DELETED_MASK) ? TRUE : FALSE; }
//Validates a pointer
BOOL ValidateBlock(DWORD_PTR dwBlock)
#if (defined DEBUG || defined _DEBUG)
;
#pragma message("MMF heap validation enabled.")
#else
{ return TRUE;}
#endif
// Grows the size of the arena by a minumum of the specified amount
DWORD_PTR GrowArena(DWORD dwGrowBySize);
//For a given offset, return the mapped base offset and size
DWORD_PTR GetBlockBaseAddress(DWORD_PTR dwOffset, DWORD &dwSize);
MMFOffsetItem *CreateNewPage(DWORD_PTR dwBaseOffset, DWORD dwSize);
MMFOffsetItem *CreateBasePage(DWORD dwInitSize, DWORD dwGanularity);
MMFOffsetItem *OpenBasePage(DWORD &dwSizeOfRepository);
MMFOffsetItem *OpenExistingPage(DWORD_PTR dwBaseOffset);
void ClosePage(MMFOffsetItem *pOffsetItem);
void CloseAllPages();
public:
enum { create_new, use_existing };
// Constructor.
CMMFArena2(bool bReadOnly = false);
// Destructor.
~CMMFArena2();
//Methods to open an MMF
bool LoadMMF(const TCHAR *pszFile);
bool CreateNewMMF(const TCHAR *pszFile,
DWORD dwGranularity,
DWORD dwInitSize);
// Allocates a block of memory.
DWORD_PTR Alloc(IN DWORD dwBytes);
// Reallocates a block of memory.
DWORD_PTR Realloc(DWORD_PTR dwOriginal, DWORD dwNewSize);
// Frees a block of memory.
BOOL Free(DWORD_PTR dwBlock);
DWORD Size(DWORD_PTR dwBlock);
//Writes any changes not already commited in the MMF to disk.
BOOL Flush();
BOOL Flush(DWORD_PTR dwOffsetToFlush);
void SetVersion(DWORD dwVersion) { if (m_pHeapDescriptor) m_pHeapDescriptor->m_dwVersion = dwVersion; }
DWORD GetVersion() { return (m_pHeapDescriptor? m_pHeapDescriptor->m_dwVersion : 0); }
DWORD_PTR GetRootBlock();
void SetRootBlock(DWORD_PTR dwRootBlock) { if (m_pHeapDescriptor) m_pHeapDescriptor->m_dwRootBlock = dwRootBlock; }
DWORD GetStatus() { return m_dwStatus; }
// Tells the amount of memory remaining without a remap or new extent.
// ===================================================================
DWORD_PTR ExtentMemAvail()
{ return (m_pHeapDescriptor ? (m_pHeapDescriptor->m_dwEndOfHeap - m_pHeapDescriptor->m_dwHeapExtent) : 0);
}
//Given an offset, returns a fixed up pointer
LPBYTE OffsetToPtr(DWORD_PTR dwOffset);
//Given a pointer, returns an offset from the start of the MMF
DWORD_PTR PtrToOffset(LPBYTE pBlock);
// Gets summary heap information.
// ==============================
void GetHeapInfo(
DWORD *pdwTotalSize,
DWORD *pdwActiveBlocks,
DWORD *pdwActiveBytes,
DWORD *pdwFreeBlocks,
DWORD *pdwFreeBytes
);
MMF_ARENA_HEADER *GetMMFHeader() { return m_pHeapDescriptor; }
//Dumps the heap to a file
void TextDump(const char *pszFile);
//Checks the deleted bit of the size block
BOOL IsDeleted(DWORD_PTR dwBlock) { return IsDeleted((MMF_BLOCK_HEADER*)(OffsetToPtr(dwBlock - sizeof(MMF_BLOCK_HEADER)))); }
BOOL IsValidBlock(DWORD_PTR dwBlock) { return ValidateBlock(dwBlock - sizeof(MMF_BLOCK_HEADER)); }
//Does a check of the MMF file to make sure it is valid. At time of writing this only
//checks the file size.
static BOOL FileValid(const TCHAR *pszFilename);
bool MappingGood() { return true; }
};
//***************************************************************************
//
// Fixup helpers.
//
// These are all strongly type variations of the same thing: they fix
// up the based ptr to a dereferenceable pointer or take the ptr and
// fix it back down to an offset.
//
//***************************************************************************
extern CMMFArena2* g_pDbArena;
template <class T> T Fixup(T ptr)
{ return T(g_pDbArena->OffsetToPtr(DWORD_PTR(ptr))); }
template <class T> T Fixdown(T ptr)
{ return T(g_pDbArena->PtrToOffset(LPBYTE(ptr))); }
template <class T> class Offset_Ptr
{
private:
T *m_pTarget;
T *m_poTarget;
protected:
void SetValue(T *val) { m_pTarget = Fixup(val); m_poTarget = val;}
void SetValue(Offset_Ptr &val) { m_pTarget = val.m_pTarget; m_poTarget = val.m_poTarget; }
public:
Offset_Ptr() : m_pTarget(0), m_poTarget(0) {}
T* operator ->() { return m_pTarget; }
DWORD_PTR GetDWORD_PTR() { return DWORD_PTR(m_poTarget); }
T* GetOffset() { return m_poTarget; }
T* GetPtr() { return m_pTarget; }
};
#endif