Function MappedFileOpenRead

roomedit/source/dibutil.cpp:314–342

/ * MappedFileOpenRead: Open filename as a memory-mapped file for read-only access, * and map a view of the entire file. Returns True on success, and fills in f. */

 *   and map a view of the entire file.  Returns True on success, and fills in f.
 */
Bool MappedFileOpenRead(const char *filename, file_node *f)
{
   f->fh = CreateFile(filename,GENERIC_READ,0,NULL,
		      OPEN_EXISTING,FILE_ATTRIBUTE_NORMAL | FILE_FLAG_SEQUENTIAL_SCAN,NULL);
   if (f->fh == INVALID_HANDLE_VALUE)
   {
      return False;
   }

   f->length = GetFileSize(f->fh, NULL);

   f->mapfh = CreateFileMapping(f->fh,NULL,PAGE_READONLY,0,f->length,NULL);
   if (f->mapfh == NULL)
   {
      CloseHandle(f->fh);
      return False;
   }

   f->mem = (char *) MapViewOfFile(f->mapfh,FILE_MAP_READ,0,0,0);
   if (f->mem == NULL)
   {
      CloseHandle(f->mapfh);
      CloseHandle(f->fh);
      return False;
   }

   f->ptr = f->mem;
   return True;
}
/***************************************************************************/
/*
 * MappedFileRead:  Copy num bytes from the memory-mapped file to buf.