Vitrual Memory Wrapper Class

// Module: VMemory.h
// Copyright(C) 2004 Arman Sahakyan

#ifndef __MODULE_USER_ARM_S__2004_8_7_11_39__TTWI__VIRTUAL_MEMORY_H_
#define __MODULE_USER_ARM_S__2004_8_7_11_39__TTWI__VIRTUAL_MEMORY_H_

class CVMemory
{
	PVOID m_pvBase;
	DWORD m_dwSize;
public:
	CVMemory() {
		m_pvBase = NULL;
		m_dwSize = 0;
	}
	~CVMemory() {
		Release();
	}

	PVOID Reserve(
		DWORD dwSize, 
		PVOID pvBaseAddr = NULL, 
		DWORD fdwProtect = PAGE_READWRITE);
	
	PVOID Commit(
		DWORD dwSize = -1, 
		PVOID pvBaseAddr = NULL, 
		DWORD fdwProtect = PAGE_READWRITE);

	PVOID ReserveCommit(
		DWORD dwSize, 
		PVOID pvBaseAddr = NULL, 
		DWORD fdwProtect = PAGE_READWRITE); 

	void Decommit(DWORD dwSize = -1, PVOID pvAddress = NULL);
 
	BOOL Release();

	DWORD GetSize() const { return m_dwSize; }
	DWORD GetRealSize() const { 
		return m_dwSize == 0 ? 0 : ((m_dwSize / 4096) + 1) * 4096; 
	}
	operator PVOID () {
		return m_pvBase;
	}
};

inline PVOID CVMemory::Reserve(DWORD dwSize, PVOID pvBaseAddr/* = NULL*/, DWORD fdwProtect /*= PAGE_READWRITE*/)
{
	ASSERT(m_pvBase == NULL);
	DWORD fdwFlags = MEM_RESERVE;
	if (pvBaseAddr) fdwFlags |= MEM_TOP_DOWN;
	m_dwSize = dwSize;
	return m_pvBase = ::VirtualAlloc(pvBaseAddr, dwSize, fdwFlags, fdwProtect);
}

inline BOOL CVMemory::Release()
{
	BOOL fRes = ::VirtualFree(m_pvBase, 0, MEM_RELEASE);
	if (fRes) { m_pvBase = NULL; m_dwSize = 0; }
	return fRes;
}

inline PVOID CVMemory::Commit(DWORD dwSize /*= -1*/, PVOID pvBaseAddr /*= NULL*/, DWORD fdwProtect /*= PAGE_READWRITE*/)
{
	PVOID pBase = m_pvBase;
	if (pvBaseAddr) pBase = pvBaseAddr;
	DWORD dwSz = m_dwSize;
	if (dwSize != -1) dwSz = dwSize;

	return ::VirtualAlloc(pBase, dwSz, MEM_COMMIT, fdwProtect);
}

inline PVOID CVMemory::ReserveCommit(DWORD dwSize, PVOID pvBaseAddr /*= NULL*/, DWORD fdwProtect /*= PAGE_READWRITE*/)
{
	ASSERT(m_pvBase == NULL);
	DWORD fdwFlags = MEM_RESERVE | MEM_COMMIT;
	if (pvBaseAddr) fdwFlags |= MEM_TOP_DOWN;
	m_dwSize = dwSize;
	return m_pvBase = ::VirtualAlloc(pvBaseAddr, dwSize, fdwFlags, fdwProtect);
}

inline void CVMemory::Decommit(DWORD dwSize /* = -1*/, PVOID pvAddress /*= NULL*/)
{
	PVOID pBase = m_pvBase;
	if (pvAddress) pBase = pvAddress;
	DWORD dwSz = m_dwSize;
	if (dwSize != -1) dwSz = dwSize;
	::VirtualFree(pBase, dwSz, MEM_DECOMMIT);
}


#endif // __MODULE_USER_ARM_S__2004_8_7_11_39__TTWI__VIRTUAL_MEMORY_H_