pjs/mailnews/mapi/old/mapi32/smem.cpp

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//
//  smem.cpp - This deals with all shared memory functions needed for 
//  the MAPI component of Communicator
//  Written by: Rich Pizzarro (rhp@netscape.com)
//  November 1997
//
#include <windows.h>
#include <windowsx.h>

#include "mapismem.h"

#ifndef ZeroMemory
#include <memory.h>
#define ZeroMemory(PTR, SIZE) memset(PTR, 0, SIZE)
#endif // ZeroMemory

// 
// *create new* shared memory chunk 
// once this is created, use the pointer
// to the segment to to store data 
// e.g.: 
//     lpString = "string for communicator"; 
//     lstrcpy((LPSTR)pData->m_buf[0], lpString); 
//  
CSharedMem *
NSCreateSharedMemory(DWORD memSize, LPCTSTR memName, HANDLE *hSharedMemory)
{
#ifdef WIN32

  BOOL bExistedBefore;
  CSharedMem *pData;

  LPCTSTR szObjectName = memName; 
  DWORD dwSize = sizeof(CSharedMem) + memSize; 
  *hSharedMemory = CreateFileMapping( 
    (HANDLE)0xFFFFFFFF,0,PAGE_READWRITE,0,dwSize,szObjectName); 
  if(*hSharedMemory == 0) 
  { 
    return NULL; 
  } 
  bExistedBefore = (GetLastError() == ERROR_ALREADY_EXISTS); 
  if(bExistedBefore) 
  { 
  	return NULL;
  } 

  pData = (CSharedMem *)MapViewOfFile( 
            *hSharedMemory, FILE_MAP_ALL_ACCESS, 0, 0, 0); 
  if(pData == NULL) 
  { 
    return NULL; 
  } 

  ZeroMemory(pData, dwSize); 
  pData->m_dwSize = memSize; 

  return pData;
#else
  CSharedMem 	*sMemChunk = NULL;
  DWORD dwSize = memSize = (sizeof(CSharedMem) + memSize); 

  if (sMemChunk != NULL)
	  return(sMemChunk);

  sMemChunk = (CSharedMem *) GlobalAllocPtr(GMEM_MOVEABLE, dwSize);
  ZeroMemory(sMemChunk, (size_t) dwSize);
  sMemChunk->m_dwSize = dwSize;   // Missing in Communicator code!
  return(sMemChunk);

#endif // WIN32
}

// 
// *open existing* shared memory chunk 
// once you have the pointer to the new segment 
// use this pointer to access data, e.g.: 
// 
CSharedMem *
NSOpenExistingSharedMemory(LPCTSTR memName, HANDLE *hSharedMemory)
{
#ifdef WIN32
  CSharedMem *pData;
  DWORD dwSize;

  LPCTSTR szObjectName = memName; 
  *hSharedMemory = OpenFileMapping( 
    PAGE_READWRITE,FALSE,szObjectName); 
  if(*hSharedMemory == 0) 
  { 
    return NULL; 
  } 

  pData = (CSharedMem *)MapViewOfFile( 
              *hSharedMemory,FILE_MAP_ALL_ACCESS,0,0,0); 
  if(pData == NULL) 
  { 
    return NULL; 
  } 
  
  dwSize = pData->m_dwSize; 
  return pData;
#else

  return(NULL);   // In Win16, this is really meaningless...

#endif
}  

// 
// to close shared memory segment
// 
void
NSCloseSharedMemory(CSharedMem *pData, HANDLE hSharedMemory)
{
#ifdef WIN32
  if(pData != 0) 
  { 
    UnmapViewOfFile(pData); 
    pData = 0; 
  } 

  if(hSharedMemory != 0) 
  { 
    CloseHandle(hSharedMemory); 
    hSharedMemory = 0; 
  } 
#else

	if (pData != NULL)
	{
		GlobalFreePtr(pData);
		pData = NULL;
	}

#endif // WIN32
}