#include "stdafx.h"
#include "CShareMemManager.h"


bool IsWin9X()
{
	//OSVERSIONINFO SysOSVersionInfo;
	//SysOSVersionInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
	//GetVersionEx(&SysOSVersionInfo);
	//if (SysOSVersionInfo.dwPlatformId == VER_PLATFORM_WIN32_WINDOWS)
	//	return true;
	//else
		return false;  
}
bool IsWinNT()
{
	//OSVERSIONINFO SysOSVersionInfo;
	//SysOSVersionInfo.dwOSVersionInfoSize = sizeof(OSVERSIONINFO);
	//GetVersionEx(&SysOSVersionInfo);
	//if (SysOSVersionInfo.dwPlatformId == VER_PLATFORM_WIN32_NT)
		return true;
	//else
	//	return false;  
}


CShareMem::CShareMem(std::string MemName)
{
	m_ShareMemHandle = NULL;
	m_ShareMemMapHandle = NULL;
	m_ShareMemAddr = NULL;
	m_ShareMemName = MemName;
	m_ShareMemSize = 0;
}
CShareMem::~CShareMem()
{
	CloseShareMemMap();
	if(m_ShareMemHandle == NULL)
		return;
	if(! CloseHandle(m_ShareMemHandle))
		return;
	m_ShareMemHandle = NULL;
}

//CreatShareMem函数创建共享内存
//参数ShareMemLen为共享内存的大小（字节为单位）
bool CShareMem::CreateShareMem(DWORD ShareMemLen)
{
	SECURITY_ATTRIBUTES SecurityAttributes;
	SECURITY_DESCRIPTOR SecurityDescriptor;
	HANDLE _ShareMemHandle = NULL;
	if ((!IsWinNT()) && (!IsWin9X()))
		return false;
	if (IsWinNT())
	{
		InitializeSecurityDescriptor(&SecurityDescriptor, SECURITY_DESCRIPTOR_REVISION);
		SetSecurityDescriptorDacl(&SecurityDescriptor, true, NULL, false);
		SecurityAttributes.nLength = sizeof(SecurityAttributes);
		SecurityAttributes.lpSecurityDescriptor = &SecurityDescriptor;
		SecurityAttributes.bInheritHandle = true;

		_ShareMemHandle = CreateFileMapping(NULL,
			&SecurityAttributes,
			PAGE_READWRITE,
			0,
			ShareMemLen,
			m_ShareMemName.c_str());
	}
	if (IsWin9X())
	{
		_ShareMemHandle = CreateFileMapping(NULL,
			NULL,
			PAGE_READWRITE,
			0,
			ShareMemLen,
			m_ShareMemName.c_str());
	}
	m_ShareMemHandle = _ShareMemHandle;
	m_ShareMemSize = ShareMemLen;
	if ((_ShareMemHandle != NULL) && (GetLastError() == ERROR_ALREADY_EXISTS))
	{
		return true;
	}

	if (_ShareMemHandle == NULL)
	{
		return false;
	}

	return true;
}

DWORD CShareMem::GetShareMemSize()
{
	return m_ShareMemSize;
}

//OpenShareMem函数打开共享内存
bool CShareMem::OpenShareMemMap()
{
	if((m_ShareMemMapHandle!= NULL)&&(m_ShareMemAddr != NULL))
		return true;
    HANDLE _ShareMemMapHandle = OpenFileMapping(FILE_MAP_ALL_ACCESS,false,m_ShareMemName.c_str());
	if (_ShareMemMapHandle == NULL)
	{
        DWORD ErrorCode = GetLastError();

		if( ErrorCode == ERROR_FILE_NOT_FOUND)
			return false;
    
		if ( IsWin9X() )
			// Windows 98下,找不到共享内存,返回值是 ERROR_FILE_NOT_FOUND
		{
			if( ErrorCode == ERROR_INVALID_NAME) 
			{
				return false;
			}
		}

		if( ErrorCode == ERROR_ACCESS_DENIED)
		{
			//Application.MessageBox('共享内存拒绝访问错误！','系统错误',MB_OK);
			return false;
		}
	}
	m_ShareMemMapHandle = _ShareMemMapHandle;
	LPVOID ShareMemAddr = MapViewOfFile(m_ShareMemMapHandle,
		FILE_MAP_READ|FILE_MAP_WRITE,
		0,
		0,
		0);
	if( ShareMemAddr== NULL)
	{
		//Application.MessageBox('映射共享内存错误！','映射共享内存',MB_OK);
		return false;
	}
	m_ShareMemAddr = ShareMemAddr;
	return true;
}

//CloseShareMem函数关闭共享内存
bool CShareMem::CloseShareMemMap()
{
	if(m_ShareMemAddr != NULL)
	{
		if(!UnmapViewOfFile(m_ShareMemAddr))
			return false;
		m_ShareMemAddr = NULL;
	}

	if(m_ShareMemMapHandle != NULL)
	{
		if(! CloseHandle(m_ShareMemMapHandle))
			return false;
		m_ShareMemMapHandle = NULL;
	}
	return true;	
}

bool CShareMem::ReadShareMem(LPVOID Data,LONG DataSize)
{
	if ( !OpenShareMemMap())
		return false;

	memcpy((LPVOID)Data,m_ShareMemAddr,DataSize);
	return true;
}

bool CShareMem::ReadShareMemEx(LONG Positon,LPVOID Data,LONG DataSize)
{
	if ( !OpenShareMemMap())
		return false;

	memcpy((LPVOID)Data,(LPCSTR)m_ShareMemAddr+Positon,DataSize);
	return true;
}

bool CShareMem::WriteShareMem(LPVOID Data,LONG DataSize)
{
	if ( !OpenShareMemMap())
		return false;
    
	memcpy(m_ShareMemAddr,(LPVOID)Data,DataSize);
	return true;
}

bool CShareMem::WriteShareMemEx(LONG Positon,LPVOID Data,LONG DataSize)
{
	if ( !OpenShareMemMap())
		return false;

	memcpy((LPVOID)((LPCSTR)m_ShareMemAddr+Positon),(LPVOID)Data,DataSize);
	return true;
}