changed the modules to use the new BACNet string types.

Modified the device object to handle having the string properties changed via WriteProperty service.
Updated the unit tests.
Updated the demo objects.

bacnet-stack/handlers.c

@@ -713,7 +713,6 @@ void AtomicReadFileHandler(
   int bytes_sent = 0;
   BACNET_ERROR_CLASS error_class = ERROR_CLASS_OBJECT;
   BACNET_ERROR_CODE error_code = ERROR_CODE_UNKNOWN_OBJECT;
-  char buffer[MAX_APDU - 16] = ""; // for reply data, less apdu overhead
 
   fprintf(stderr,"Received Atomic-Read-File Request!\n");
   len = arf_decode_service_request(
@@ -754,9 +753,8 @@ void AtomicReadFileHandler(
   {
     if (data.access == FILE_STREAM_ACCESS)
     {
-      data.fileData = (uint8_t *)&buffer[0];
-      data.fileDataLength = sizeof(buffer);
-      if (data.type.stream.requestedOctetCount < data.fileDataLength)
+      if (data.type.stream.requestedOctetCount <
+          octetstring_capacity(&data.fileData))
       {
         if (bacfile_read_data(&data))
         {
@@ -855,12 +853,13 @@ void AtomicReadFileAckHandler(
           (void)fseek(pFile,
             data.type.stream.fileStartPosition,
             SEEK_SET);
-          if (fwrite(data.fileData,data.fileDataLength,1,pFile) != 1)
+          if (fwrite(octetstring_value(&data.fileData),
+              octetstring_length(&data.fileData),1,pFile) != 1)
             fprintf(stderr,"Failed to write to %s (%u)!\n",
               pFilename, instance);
           fclose(pFile);
         }
-      }      
+      }
     }
     else if (data.access == FILE_RECORD_ACCESS)
     {