Source code of Windows XP (NT5)
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//***************************************************************************
//
// (c) 2000 Microsoft Corp. All Rights Reserved.
//
// BTR.H
//
// Repository B-tree classes
//
// raymcc 15-Oct-00 First version
//
//***************************************************************************
#ifndef _BTR_H_
#define _BTR_H_
#include "absfile.h"
#define A51_INDEX_FILE_ID 2
LPVOID WINAPI _BtrMemAlloc(
SIZE_T dwBytes // number of bytes to allocate
);
LPVOID WINAPI _BtrMemReAlloc(
LPVOID pOriginal,
DWORD dwNewBytes
);
BOOL WINAPI _BtrMemFree(LPVOID pMem);
#define ReleaseIfNotNULL(p) if(p) p->Release()
class CPageSource
{
DWORD m_dwPageSize;
HANDLE m_hFile;
DWORD m_dwTotalPages;
DWORD m_dwLogicalRoot;
DWORD m_dwNextFreePage; // 0==none
DWORD m_dwLastFlushTime;
#ifdef A51_STAGE_BELOW_INDEX
CAbstractFile* m_pFile;
#endif
// Methods
DWORD Setup();
DWORD WriteAdminPage();
public:
CPageSource();
~CPageSource();
enum { const_DefaultPageSize = 0x2000, const_CurrentVersion = 0x101 };
enum {
PAGE_TYPE_IMPOSSIBLE = 0x0, // Not supposed to happen
PAGE_TYPE_ACTIVE = 0xACCC, // Page is active with data
PAGE_TYPE_DELETED = 0xBADD, // A deleted page on free list
PAGE_TYPE_ADMIN = 0xADDD, // Page zero only
// All pages
OFFSET_PAGE_TYPE = 0, // True for all pages
OFFSET_PAGE_ID = 1, // True for all pages
OFFSET_NEXT_PAGE = 2, // True for all pages (Page continuator)
// Admin Page (page zero) only
OFFSET_LOGICAL_ROOT = 3, // Root of database
OFFSET_FREE_LIST_ROOT = 4, // First free list page
OFFSET_TOTAL_PAGES = 5, // Total page in database
OFFSET_PAGE_SIZE = 6, // Page size check
OFFSET_IMPL_VERSION = 7, // Implementation version
};
DWORD Init(
DWORD dwPageSize, // 8k default
LPWSTR pszFilename
#ifdef A51_STAGE_BELOW_INDEX
, CAbstractFileSource* pSource
#endif
);
DWORD Shutdown(DWORD dwShutDownFlags);
DWORD GetPage(DWORD dwId, LPVOID *pPage);
DWORD PutPage(LPVOID pPage, DWORD dwType);
DWORD NewPage(LPVOID *pPage);
DWORD FreePage(LPVOID pPage);
DWORD FreePage(DWORD dwId);
DWORD GetPageSize() { return m_dwPageSize; }
DWORD SetRootPage(DWORD dwID);
DWORD GetRootPage() { return m_dwLogicalRoot; }
void Flush() { FlushFileBuffers(m_hFile); }
DWORD ReadAdminPage();
void Dump(FILE *);
};
struct SIdxStringPool
{
DWORD m_dwNumStrings; // Number of strings in pool
WORD *m_pwOffsets; // Offsets into pool of strings
DWORD m_dwOffsetsSize; // Number of elements in above array
LPSTR m_pStringPool; // Pointer to string pool
DWORD m_dwPoolTotalSize; // Total size, used+unused
DWORD m_dwPoolUsed; // Offset of first free position
public:
enum { const_DefaultPoolSize = 0x2200 };
SIdxStringPool() { memset(this, 0, sizeof(SIdxStringPool)); }
~SIdxStringPool();
DWORD AddStr(LPSTR pszStr, WORD wInsertPos, int *pnAdjuster);
DWORD DeleteStr(WORD wAssignedOffset, int *pnAdjuster);
DWORD GetLastId() { return m_dwNumStrings; }
DWORD FindStr(
IN LPSTR pszSearchKey,
OUT WORD *pwStringNumber,
OUT WORD *pwPoolOffset
);
DWORD GetNumStrings() { return m_dwNumStrings; }
DWORD GetRequiredPageMemory()
{
return m_dwPoolUsed + (m_dwNumStrings * sizeof(WORD)) +
sizeof(m_dwNumStrings) + sizeof(m_dwPoolUsed);
}
DWORD Dump(FILE *f);
LPSTR GetStrById(WORD id) { return m_pStringPool+m_pwOffsets[id]; }
void Empty() { m_dwNumStrings = 0; m_dwPoolUsed = 0; }
DWORD Clone(SIdxStringPool **);
};
class SIdxKeyTable
{
DWORD m_dwRefCount; // Ref count
DWORD m_dwPageId; // Page number
DWORD m_dwParentPageId; // Parent page id <For DEBUGGING only>
DWORD m_dwNumKeys; // Num keys
WORD *m_pwKeyLookup; // Offset of key into key-encoding-table
DWORD m_dwKeyLookupTotalSize; // Elements in array
DWORD *m_pdwUserData; // User DWORD with each key
DWORD *m_pdwChildPageMap; // Child page pointers n=left ptr, n+1=right pointer
WORD *m_pwKeyCodes; // Key encoding table
DWORD m_dwKeyCodesTotalSize; // Total elements in array
DWORD m_dwKeyCodesUsed; // Elements used
SIdxStringPool *m_pStrPool; // The pool associated with this key table
// Methods
SIdxKeyTable();
~SIdxKeyTable();
public:
enum { const_DefaultArray = 256,
const_DefaultKeyCodeArray = 512
};
static DWORD Create(DWORD dwPageId, SIdxKeyTable **pNew);
static DWORD Create(LPVOID pPage, SIdxKeyTable **pNew);
DWORD AddRef();
DWORD Release();
DWORD AddKey(LPSTR pszStr, WORD ID, DWORD dwUserData);
DWORD RemoveKey(WORD wID);
DWORD FindKey(LPSTR pszStr, WORD *pID);
DWORD GetUserData(WORD wID) { return m_pdwUserData[wID]; }
void SetChildPage(WORD wID, DWORD dwPage) { m_pdwChildPageMap[wID] = dwPage; }
DWORD GetChildPage(WORD wID) { return m_pdwChildPageMap[wID]; }
DWORD GetLastChildPage() { return m_pdwChildPageMap[m_dwNumKeys]; }
DWORD GetLeftSiblingOf(DWORD dwId);
DWORD GetRightSiblingOf(DWORD dwId);
DWORD GetKeyAt(WORD wID, LPSTR *pszKey); // Use _MemFree
DWORD GetNumKeys() { return m_dwNumKeys; }
void SetStringPool(SIdxStringPool *pPool) { m_pStrPool = pPool; }
void FreeMem(LPVOID pMem);
void AdjustKeyCodes(
WORD wID,
int nAdjustment
);
int KeyStrCompare(
LPSTR pszSearchKey,
WORD wID
);
DWORD Cleanup();
DWORD NumKeys() { return m_dwNumKeys; }
DWORD GetRequiredPageMemory();
DWORD Dump(FILE *, DWORD *pdwKeys = 0);
void ZapPage();
DWORD GetPageId() { return m_dwPageId; }
// Sibling/Parent page helpers
DWORD GetKeyOverhead(WORD wID); // Returns total bytes required by new key
BOOL IsLeaf() { return m_pdwChildPageMap[0] == 0; }
DWORD Redist(
SIdxKeyTable *pParent,
SIdxKeyTable *pNewSibling
);
DWORD Collapse(
SIdxKeyTable *pParent,
SIdxKeyTable *pDoomedSibling
);
DWORD StealKeyFromSibling(
SIdxKeyTable *pParent,
SIdxKeyTable *pSibling
);
DWORD MapFromPage(LPVOID pSrc);
DWORD MapToPage(LPVOID pMem);
DWORD Clone(OUT SIdxKeyTable **pCopy);
};
class CBTree;
class CBTreeIterator
{
friend class CBTree;
enum {
const_MaxStack = 1024,
const_PrefetchSize = 64
};
CBTree *m_pTree;
SIdxKeyTable *m_Stack[const_MaxStack];
WORD m_wStack[const_MaxStack];
LONG m_lStackPointer;
LPSTR *m_pPrefetchKeys[const_PrefetchSize];
DWORD m_dwPrefetchData[const_PrefetchSize];
DWORD m_dwPrefetchActive;
~CBTreeIterator();
// Stack helpers
SIdxKeyTable *Peek() { return m_Stack[m_lStackPointer]; }
WORD PeekId() { return m_wStack[m_lStackPointer]; }
void IncStackId() { m_wStack[m_lStackPointer]++; }
void Pop() { ReleaseIfNotNULL(m_Stack[m_lStackPointer]); m_lStackPointer--; }
BOOL StackFull() { return m_lStackPointer == const_MaxStack - 1; }
void Push(SIdxKeyTable *p, WORD wId) { m_Stack[++m_lStackPointer] = p; m_wStack[m_lStackPointer] = wId; }
DWORD ZapStack();
DWORD PurgeKey(LPSTR pszDoomedKey);
DWORD RebuildStack(LPSTR pszStartKey);
DWORD ExecPrefetch();
static DWORD ZapAllStacks();
static DWORD GlobalPurgeKey(LPSTR pszDoomedKey);
public:
CBTreeIterator() { m_pTree = 0; m_lStackPointer = -1; }
DWORD Init(CBTree *pRoot, LPSTR pszStartKey = 0); // If last parm is null, iterate through all
DWORD Next(LPSTR *ppszStr, DWORD *pdwData = 0);
void FreeString(LPSTR pszStr) { _BtrMemFree(pszStr); }
DWORD Release();
};
class CBTree
{
enum { const_DefaultArray = 256 };
enum { const_MinimumLoad = 33 };
CPageSource *m_pSrc;
SIdxKeyTable *m_pRoot;
friend class CBTreeIterator;
LONG m_lGeneration;
CRITICAL_SECTION m_cs;
CBTreeIterator *m_pIterators;
DWORD m_dwActiveIterators;
DWORD m_dwIteratorsArraySize;
// private methods
DWORD ReplaceBySuccessor(
IN SIdxKeyTable *pIdx,
IN WORD wId,
OUT LPSTR *pszSuccessorKey,
OUT BOOL *pbUnderflowDetected,
DWORD Stack[],
LONG &StackPtr
);
DWORD FindSuccessorNode(
IN SIdxKeyTable *pIdx,
IN WORD wId,
OUT SIdxKeyTable **pSuccessor,
OUT DWORD *pdwPredecessorChild,
DWORD Stack[],
LONG &StackPtr
);
DWORD ReadIdxPage(
DWORD dwPage,
SIdxKeyTable **pIdx
);
DWORD WriteIdxPage(
SIdxKeyTable *pIdx
);
DWORD ComputeLoad(
SIdxKeyTable *pKT
);
DWORD InsertPhase2(
SIdxKeyTable *pCurrent,
WORD wID,
LPSTR pszKey,
DWORD dwValue,
DWORD Stack[],
LONG &StackPtr
);
DWORD Search(
IN LPSTR pszKey,
OUT SIdxKeyTable **pRetIdx,
OUT WORD *pwID,
DWORD Stack[],
LONG &StackPtr
);
public:
CBTree();
~CBTree();
DWORD Init(CPageSource *pSrc);
DWORD Shutdown(DWORD dwShutDownFlags);
DWORD InsertKey(
IN LPSTR pszKey,
DWORD dwValue
);
DWORD FindKey(
IN LPSTR pszKey,
DWORD *pdwData
);
DWORD DeleteKey(
IN LPSTR pszKey
);
DWORD BeginEnum(
LPSTR pszStartKey,
OUT CBTreeIterator **pIterator
);
void Dump(FILE *fp);
DWORD InvalidateCache();
};
#endif