myvtm/Other/libsharememory/libsharememory.cpp

// libsharememory.cpp : 定义 DLL 应用程序的导出函数。
//

#include "stdafx.h"
#include "libsharememory.h"
#include <stdio.h>

class libsharememory_impl
{
protected:
	DWORD m_dwBytes;
	HANDLE m_hFileMap;
	BOOL m_bLocked;
	LPVOID m_pData;
	//HANDLE m_hFile;
	HANDLE m_hMutex;
	//int m_nEntityNum;

public:
	libsharememory_impl()
	{
		//m_hFile=INVALID_HANDLE_VALUE;
		m_hMutex=NULL;
		m_pData=NULL;
		m_hFileMap=NULL;
		m_dwBytes=0;
		//m_nEntityNum = 0;
	}

	~libsharememory_impl()
	{
		CloseShareMem();
	}

	//创建共享内存区
	BOOL CreateShareMem(LPCTSTR szName, DWORD dwBytes)
	{
		BOOL T=FALSE;
		char szBuf[MAX_PATH];
		LPCTSTR szFile;
		if(szName!=NULL&&dwBytes>0)
		{
			CloseShareMem();
			szFile=tmpnam(szBuf);
			if(szFile!=NULL)
			{
				m_hFileMap=CreateFileMapping(INVALID_HANDLE_VALUE, NULL, PAGE_READWRITE, 0, dwBytes+sizeof(DWORD)+sizeof(int), szName);
				if(m_hFileMap!=NULL)
				{
					m_dwBytes=dwBytes;
					m_pData=MapViewOfFile(m_hFileMap, FILE_MAP_ALL_ACCESS, 0, 0, 0);
					if(m_pData!=NULL)
					{
						*((LPDWORD)m_pData)=dwBytes;
						//*((int*)((LPDWORD)m_pData+1))= ++m_nEntityNum;
						sprintf_s(szBuf, "Mutex<%s>", szName);
						m_hMutex=CreateMutex(NULL, FALSE, szBuf);
						if(m_hMutex!=NULL)
						{
							if(GetLastError()!=ERROR_ALREADY_EXISTS)
							{
								T=TRUE;
							}
						}
					}
				}
				if(!T)
				{
					CloseShareMem();
				}
			}
		}
		return T;
	}
	//打开已有的共享内存区
	BOOL OpenShareMem(LPCTSTR szName)
	{
		BOOL T=FALSE;
		char szBuf[MAX_PATH];
		if(szName!=NULL)
		{
			CloseShareMem();
			m_hFileMap=OpenFileMapping(FILE_MAP_ALL_ACCESS, FALSE, szName);
			if(m_hFileMap!=NULL)
			{
				sprintf_s(szBuf, "Mutex<%s>", szName);
				m_hMutex=OpenMutex(MUTEX_ALL_ACCESS, FALSE, szBuf);
				if(m_hMutex!=NULL)
				{
					m_pData=MapViewOfFile(m_hFileMap, FILE_MAP_ALL_ACCESS, 0, 0, 0);
					if(LockShareMem())
					{
						m_dwBytes=*((LPDWORD)m_pData);
						//m_nEntityNum = *((int*)((LPDWORD)m_pData+1));
						//*((int*)((LPDWORD)m_pData+1)) = ++m_nEntityNum;
						UnlockShareMem();
						if(m_dwBytes>0)
						{
							T=TRUE;
						}
					}
				}
			}
			if(!T)
			{
				CloseShareMem();
			}
		}
		return T;
	}

	//释放共享内存区
	VOID CloseShareMem()
	{
		if(m_bLocked)
		{
			UnlockShareMem();
		}
		if(m_pData!=NULL)
		{
			UnmapViewOfFile(m_pData);
			m_pData=NULL;
		}
		if(m_hFileMap!=NULL)
		{
			CloseHandle(m_hFileMap);
			m_hFileMap=NULL;
		}
		
		if(m_hMutex!=NULL)
		{
			CloseHandle(m_hMutex);
			m_hMutex=NULL;
		}
		m_dwBytes=0;
	}

	//获取共享内存区大小
	DWORD GetShareMemBytes()
	{
		return m_dwBytes;
	}

	//int GetEntityNum()
	//{
		//LPVOID pdata = LockShareMem();
		//m_nEntityNum = *(int*)((LPDWORD)pdata+1);
		//return m_nEntityNum;
	//}

	//void DeleteEntityNum()
	//{
		//m_nEntityNum--;
	//}
	//是否有可用的内存区
	BOOL IsShareMemValid()
	{
		return (m_hFileMap!=NULL&&m_hMutex!=NULL);
	}
	//锁定访问内存区
	LPVOID LockShareMem(DWORD dwWaitTimeout=INFINITE)
	{
		LPVOID pData=NULL;
		if(IsShareMemValid()&&m_pData!=NULL&&!m_bLocked)
		{
			if(WaitForSingleObject(m_hMutex, dwWaitTimeout)!=WAIT_TIMEOUT)
			{
				m_bLocked=TRUE;
			}
			if(m_bLocked)
			{
				pData=(LPVOID)((LPDWORD)m_pData+1);
			}
		}
		return pData;
	}
	//内存区是否互斥锁定
	BOOL IsShareMemLocked()
	{
		return m_bLocked;
	}
	//解锁内存区
	VOID UnlockShareMem()
	{
		if(m_bLocked)
		{
			ReleaseMutex(m_hMutex);
			m_bLocked=FALSE;
		}
	}
};


// 这是已导出类的构造函数。
// 有关类定义的信息，请参阅 libsharememory.h
Clibsharememory::Clibsharememory()
{
	m_pImpl = new libsharememory_impl;
	return;
}

Clibsharememory::~Clibsharememory()
{
	delete m_pImpl;
}

VOID Clibsharememory::Unlock()
{
	m_pImpl->UnlockShareMem();
	return;
}

BOOL Clibsharememory::IsLocked()
{
	 BOOL bRst = m_pImpl->IsShareMemLocked();
	 return bRst;
}

LPVOID Clibsharememory::Lock(DWORD dwWaitTimeout)
{
	 LPVOID lpVoid = m_pImpl->LockShareMem(dwWaitTimeout);
	 return lpVoid;
}

BOOL Clibsharememory::IsValid()
{
	BOOL bRst = m_pImpl->IsShareMemValid();
	return bRst;
}

DWORD Clibsharememory::GetBytes()
{
	DWORD TotalBytes =  m_pImpl->GetShareMemBytes();
	return TotalBytes;
}

VOID Clibsharememory::Close()
{
	m_pImpl->CloseShareMem();
	return;
}

BOOL Clibsharememory::Open(LPCTSTR szName)
{
	BOOL bRst = m_pImpl->OpenShareMem(szName);
	return bRst;
}

BOOL Clibsharememory::Create(LPCTSTR szName, DWORD dwBytes)
{
	BOOL bRst = m_pImpl->CreateShareMem(szName,dwBytes);
	return bRst;
}

int Clibsharememory::GetEntityNum()
{
	//return m_pImpl->GetEntityNum();
	return 0;
}