Line data    Source code

       1             : /*
       2             :  *
       3             :  *    Copyright (c) 2021 Project CHIP Authors
       4             :  *
       5             :  *    Licensed under the Apache License, Version 2.0 (the "License");
       6             :  *    you may not use this file except in compliance with the License.
       7             :  *    You may obtain a copy of the License at
       8             :  *
       9             :  *        http://www.apache.org/licenses/LICENSE-2.0
      10             :  *
      11             :  *    Unless required by applicable law or agreed to in writing, software
      12             :  *    distributed under the License is distributed on an "AS IS" BASIS,
      13             :  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
      14             :  *    See the License for the specific language governing permissions and
      15             :  *    limitations under the License.
      16             :  */
      17             : 
      18             : #include "ZclString.h"
      19             : 
      20             : namespace chip {
      21             : 
      22             : // ZCL strings are stored as pascal-strings (first byte contains the length of
      23             : // the data), and a length of 255 means "invalid string" so the maximum actually
      24             : // allowed string length is 254.
      25             : constexpr size_t kBufferMaximumSize = 254;
      26             : 
      27           6 : CHIP_ERROR MakeZclCharString(MutableByteSpan & buffer, const char * cString)
      28             : {
      29           6 :     CHIP_ERROR err = CHIP_NO_ERROR;
      30             : 
      31           6 :     if (buffer.size() == 0)
      32             :     {
      33             :         // We can't even put a 0 length in there.
      34           0 :         return CHIP_ERROR_INBOUND_MESSAGE_TOO_BIG;
      35             :     }
      36           6 :     size_t len              = strlen(cString);
      37           6 :     size_t availableStorage = min(buffer.size() - 1, kBufferMaximumSize);
      38           6 :     if (len > availableStorage)
      39             :     {
      40           4 :         buffer.data()[0] = 0;
      41           4 :         return CHIP_ERROR_INBOUND_MESSAGE_TOO_BIG;
      42             :     }
      43             : 
      44           2 :     buffer.data()[0] = static_cast<uint8_t>(len);
      45           2 :     memcpy(&buffer.data()[1], cString, len);
      46           2 :     return err;
      47             : }
      48             : 
      49             : } // namespace chip