Source code of Windows XP (NT5)
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3.6 KiB

//+---------------------------------------------------------------------------
//
// Microsoft Windows
// Copyright (C) Microsoft Corporation, 1992 - 1994.
//
// File: alias.hxx
//
// Classes: CAliasBlock
// CAliases
//
// History: 26-May-94 DrewB Created
//
//----------------------------------------------------------------------------
#ifndef __ALIAS_HXX__
#define __ALIAS_HXX__
// Number of alias slots to allocate in a chunk
#define ALIAS_BLOCK_SIZE 64
typedef WORD ALIAS;
#define INVALID_ALIAS ((ALIAS)0xffff)
// Aliases should not be zero because this causes error detection problems
#define INITIAL_ALIAS ((ALIAS)1)
// Values cannot be zero, this allows us to detect free slots in the
// value array
#define INVALID_VALUE ((DWORD)0)
//+---------------------------------------------------------------------------
//
// Class: CAliasBlock (ab)
//
// Purpose: A block of values indexed by alias
//
// History: 26-May-94 DrewB Created
//
//----------------------------------------------------------------------------
class CAliasBlock
{
public:
CAliasBlock(ALIAS aliasBase,
CAliasBlock *pabNext);
BOOL ContainsAlias(ALIAS alias)
{
return alias >= _aliasBase && alias < _aliasBase+ALIAS_BLOCK_SIZE;
}
DWORD AliasValue(ALIAS alias)
{
thkAssert(!IsFree(alias));
return _dwValues[AliasIndex(alias)];
}
void RemoveAlias(ALIAS alias)
{
thkAssert(!IsFree(alias));
#if DBG == 1
CheckFree();
#endif
thkAssert(_iFilled > 0);
_iFilled--;
_dwValues[AliasIndex(alias)] = INVALID_VALUE;
}
void SetValue(ALIAS alias, DWORD dwValue)
{
thkAssert(!IsFree(alias));
thkAssert(dwValue != INVALID_VALUE);
_dwValues[AliasIndex(alias)] = dwValue;
}
ALIAS ValueAlias(DWORD dwValue);
ALIAS AddValue(DWORD dwValue);
CAliasBlock *GetNext(void)
{
return _pabNext;
}
void SetNext(CAliasBlock *pab)
{
_pabNext = pab;
}
int AliasesFilled(void)
{
return _iFilled;
}
#if DBG == 1
BOOL IsFree(ALIAS alias)
{
return _dwValues[AliasIndex(alias)] == INVALID_VALUE;
}
#endif
private:
int AliasIndex(ALIAS alias)
{
thkAssert(ContainsAlias(alias));
return (int)(alias-_aliasBase);
}
ALIAS IndexAlias(int iIndex)
{
thkAssert(iIndex >= 0 && iIndex < ALIAS_BLOCK_SIZE);
return (ALIAS)(iIndex+_aliasBase);
}
#if DBG == 1
void CheckFree(void);
#endif
ALIAS _aliasBase;
int _iFilled;
DWORD _dwValues[ALIAS_BLOCK_SIZE];
CAliasBlock *_pabNext;
};
//+---------------------------------------------------------------------------
//
// Class: CAliases (aliases)
//
// Purpose: Maintains a set of aliases for values
//
// History: 26-May-94 DrewB Created
//
// Notes: Values must be unique
//
//----------------------------------------------------------------------------
class CAliases
{
public:
CAliases(void)
: _abStatic(INITIAL_ALIAS, NULL)
{
// Start alias list with the static block
_pabAliases = &_abStatic;
// The static block takes the first block of aliases
_aliasBase = INITIAL_ALIAS+ALIAS_BLOCK_SIZE;
}
~CAliases(void);
DWORD AliasValue(ALIAS alias);
ALIAS ValueAlias(DWORD dwValue);
ALIAS AddValue(DWORD dwValue);
void RemoveAlias(ALIAS alias);
void SetValue(ALIAS alias, DWORD dwValue);
private:
void DeleteBlock(CAliasBlock *pab, CAliasBlock *pabPrev);
CAliasBlock _abStatic;
CAliasBlock *_pabAliases;
ALIAS _aliasBase;
};
#endif // #ifndef __ALIAS_HXX__