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 = std::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