#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;  
}
//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,
										  strShareMemName);
   }
   if (IsWin9X())
   {
       _ShareMemHandle=CreateFileMapping( NULL,
					                      NULL,
					                      PAGE_READWRITE,
					                      0,
					                      ShareMemLen,
					                      strShareMemName);
   }
   m_ShareMemHandle = _ShareMemHandle;
   m_ShareMemSize = ShareMemLen;
   if ((_ShareMemHandle != NULL)&&(GetLastError() == ERROR_ALREADY_EXISTS))
   {
	   return true;
   }

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


   return true;
}

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

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,
					                            (LPCTSTR)strShareMemName);

	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;

}