src/system/TLVPacketBufferBackingStore.cpp

   1 /*
   2  *
   3  *    Copyright (c) 2021 Project CHIP Authors
   4  *    Copyright (c) 2013-2017 Nest Labs, Inc.
   5  *
   6  *    Licensed under the Apache License, Version 2.0 (the "License");
   7  *    you may not use this file except in compliance with the License.
   8  *    You may obtain a copy of the License at
   9  *
  10  *        http://www.apache.org/licenses/LICENSE-2.0
  11  *
  12  *    Unless required by applicable law or agreed to in writing, software
  13  *    distributed under the License is distributed on an "AS IS" BASIS,
  14  *    WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  15  *    See the License for the specific language governing permissions and
  16  *    limitations under the License.
  17  */
  18
  19 /**
  20  *    @file
  21  *      This file contains an implementation of TLVBackingStore using PacketBuffers.
  22  */
  23
  24 #include <system/TLVPacketBufferBackingStore.h>
  25
  26 #include <support/SafeInt.h>
  27
  28 namespace chip {
  29 namespace System {
  30
  31 CHIP_ERROR TLVPacketBufferBackingStore::OnInit(chip::TLV::TLVReader & reader, const uint8_t *& bufStart, uint32_t & bufLen)
  32 {
  33     bufStart = mHeadBuffer->Start();
  34     bufLen   = mHeadBuffer->DataLength();
  35     return CHIP_NO_ERROR;
  36 }
  37
  38 CHIP_ERROR TLVPacketBufferBackingStore::GetNextBuffer(chip::TLV::TLVReader & reader, const uint8_t *& bufStart, uint32_t & bufLen)
  39 {
  40     if (mUseChainedBuffers)
  41     {
  42         mCurrentBuffer.Advance();
  43     }
  44     else
  45     {
  46         mCurrentBuffer = nullptr;
  47     }
  48
  49     if (mCurrentBuffer.IsNull())
  50     {
  51         bufStart = nullptr;
  52         bufLen   = 0;
  53     }
  54     else
  55     {
  56         bufStart = mCurrentBuffer->Start();
  57         bufLen   = mCurrentBuffer->DataLength();
  58     }
  59
  60     return CHIP_NO_ERROR;
  61 }
  62
  63 CHIP_ERROR TLVPacketBufferBackingStore::OnInit(chip::TLV::TLVWriter & writer, uint8_t *& bufStart, uint32_t & bufLen)
  64 {
  65     bufStart = mHeadBuffer->Start() + mHeadBuffer->DataLength();
  66     bufLen   = mHeadBuffer->AvailableDataLength();
  67     return CHIP_NO_ERROR;
  68 }
  69
  70 CHIP_ERROR TLVPacketBufferBackingStore::FinalizeBuffer(chip::TLV::TLVWriter & writer, uint8_t * bufStart, uint32_t dataLen)
  71 {
  72     uint8_t * endPtr = bufStart + dataLen;
  73
  74     intptr_t length = endPtr - mCurrentBuffer->Start();
  75     if (!CanCastTo<uint16_t>(length))
  76     {
  77         return CHIP_ERROR_INVALID_ARGUMENT;
  78     }
  79     mCurrentBuffer->SetDataLength(static_cast<uint16_t>(length));
  80
  81     return CHIP_NO_ERROR;
  82 }
  83
  84 CHIP_ERROR TLVPacketBufferBackingStore::GetNewBuffer(chip::TLV::TLVWriter & writer, uint8_t *& bufStart, uint32_t & bufLen)
  85 {
  86     if (!mUseChainedBuffers)
  87     {
  88         return CHIP_ERROR_NO_MEMORY;
  89     }
  90
  91     mCurrentBuffer.Advance();
  92     if (mCurrentBuffer.IsNull())
  93     {
  94         mCurrentBuffer = PacketBufferHandle::New(System::PacketBuffer::kMaxSizeWithoutReserve, 0);
  95         if (mCurrentBuffer.IsNull())
  96         {
  97             return CHIP_ERROR_NO_MEMORY;
  98         }
  99         mHeadBuffer->AddToEnd(mCurrentBuffer.Retain());
 100     }
 101
 102     if (mCurrentBuffer.IsNull())
 103     {
 104         bufStart = nullptr;
 105         bufLen   = 0;
 106     }
 107     else
 108     {
 109         bufStart = mCurrentBuffer->Start();
 110         bufLen   = mCurrentBuffer->MaxDataLength();
 111     }
 112
 113     return CHIP_NO_ERROR;
 114 }
 115
 116 } // namespace System
 117 } // namespace chip