Line data    Source code

       1              : /*
       2              :  *
       3              :  *    Copyright (c) 2024 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              : #pragma once
      18              : 
      19              : #include <cstdint>
      20              : #include <vector>
      21              : 
      22              : #include <lib/core/CHIPError.h>
      23              : #include <lib/core/TLVBackingStore.h>
      24              : #include <lib/core/TLVCommon.h>
      25              : 
      26              : namespace chip {
      27              : namespace TLV {
      28              : 
      29              : // Implementation of TLVWriter that writes to a std::vector, automatically
      30              : // resizing the vector as needed when writing.
      31              : // Users of TlvVectorWriter may call any public API of TLVWriter, except for the
      32              : // Init functions.
      33              : // This class is not thread-safe, it must be constructed, used, and destroyed on
      34              : // a single thread.
      35              : class TlvVectorWriter : public TLVWriter
      36              : {
      37              : public:
      38              :     // All data will be written to and read from the provided buffer, which must
      39              :     // outlive this object.
      40              :     TlvVectorWriter(std::vector<uint8_t> & buffer);
      41              :     TlvVectorWriter(const TlvVectorWriter &)             = delete;
      42              :     TlvVectorWriter & operator=(const TlvVectorWriter &) = delete;
      43              :     ~TlvVectorWriter();
      44              : 
      45              : private:
      46              :     class TlvVectorBuffer : public TLVBackingStore
      47              :     {
      48              :     public:
      49              :         TlvVectorBuffer(std::vector<uint8_t> & buffer);
      50              :         TlvVectorBuffer(const TlvVectorBuffer &)             = delete;
      51              :         TlvVectorBuffer & operator=(const TlvVectorBuffer &) = delete;
      52              :         ~TlvVectorBuffer() override;
      53              : 
      54              :         // TLVBackingStore implementation:
      55            0 :         CHIP_ERROR OnInit(TLVReader & reader, const uint8_t *& bufStart, uint32_t & bufLen) override
      56              :         {
      57            0 :             return CHIP_ERROR_NOT_IMPLEMENTED;
      58              :         }
      59            0 :         CHIP_ERROR GetNextBuffer(TLVReader & reader, const uint8_t *& bufStart, uint32_t & bufLen) override
      60              :         {
      61            0 :             return CHIP_ERROR_NOT_IMPLEMENTED;
      62              :         }
      63              :         CHIP_ERROR OnInit(TLVWriter & writer, uint8_t *& bufStart, uint32_t & bufLen) override;
      64              :         CHIP_ERROR GetNewBuffer(TLVWriter & writer, uint8_t *& bufStart, uint32_t & bufLen) override;
      65              :         CHIP_ERROR FinalizeBuffer(TLVWriter & writer, uint8_t * bufStart, uint32_t bufLen) override;
      66              : 
      67              :     private:
      68              :         void ResizeWriteBuffer(uint8_t *& bufStart, uint32_t & bufLen);
      69              : 
      70              :         // mWritingBuffer is the mutable buffer exposed via the TLVBackingStore
      71              :         // interface. When FinalizeBuffer is called the contents of mWritingBuffer
      72              :         // are appended to mFinalBuffer and mWritingBuffer is cleared. This allows
      73              :         // for reading all written data from a single, contiguous buffer
      74              :         // (mFinalBuffer).
      75              :         std::vector<uint8_t> mWritingBuffer;
      76              :         std::vector<uint8_t> & mFinalBuffer;
      77              :     };
      78              : 
      79              :     TlvVectorBuffer mVectorBuffer;
      80              : };
      81              : 
      82              : } // namespace TLV
      83              : } // namespace chip