low-can-binding/can/can-message.cpp

   1 /*
   2  * Copyright (C) 2015, 2016 "IoT.bzh"
   3  * Author "Romain Forlot" <romain.forlot@iot.bzh>
   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 "can-message.hpp"
  19
  20 #include <cstring>
  21
  22 #include "../binding/low-can-hat.hpp"
  23
  24 ///
  25 /// @brief Class constructor
  26 ///
  27 /// can_message_t class constructor.
  28 ///
  29 can_message_t::can_message_t()
  30         : maxdlen_{0},
  31          id_{0},
  32          length_{0},
  33          format_{can_message_format_t::INVALID},
  34          rtr_flag_{false},
  35          flags_{0},
  36          timestamp_{0},
  37          sub_id_{-1}
  38 {}
  39
  40 can_message_t::can_message_t(uint8_t maxdlen,
  41         uint32_t id,
  42         uint8_t length,
  43         can_message_format_t format,
  44         bool rtr_flag,
  45         uint8_t flags,
  46         std::vector<uint8_t>& data,
  47         uint64_t timestamp)
  48         :  maxdlen_{maxdlen},
  49         id_{id},
  50         length_{length},
  51         format_{format},
  52         rtr_flag_{rtr_flag},
  53         flags_{flags},
  54         data_{data},
  55         timestamp_{timestamp},
  56         sub_id_{-1}
  57 {}
  58
  59 ///
  60 /// @brief Retrieve id_ member value.
  61 ///
  62 /// @return id_ class member
  63 ///
  64 uint32_t can_message_t::get_id() const
  65 {
  66         return id_;
  67 }
  68
  69 int can_message_t::get_sub_id() const
  70 {
  71         return sub_id_;
  72 }
  73
  74 ///
  75 /// @brief Retrieve data_ member value.
  76 ///
  77 /// @return pointer to the first element
  78 ///  of class member data_
  79 ///
  80 const uint8_t* can_message_t::get_data() const
  81 {
  82         return data_.data();
  83 }
  84
  85 ///
  86 /// @brief Retrieve data_ member whole vector
  87 ///
  88 /// @return the vector as is
  89 ///
  90 const std::vector<uint8_t> can_message_t::get_data_vector() const
  91 {
  92         return data_;
  93 }
  94
  95 ///
  96 /// @brief Retrieve length_ member value.
  97 ///
  98 /// @return length_ class member
  99 ///
 100 uint8_t can_message_t::get_length() const
 101 {
 102         return length_;
 103 }
 104
 105 void can_message_t::set_sub_id(int sub_id)
 106 {
 107         sub_id_ = sub_id;
 108 }
 109
 110 uint64_t can_message_t::get_timestamp() const
 111 {
 112         return timestamp_;
 113 }
 114
 115 /// @brief Control whether the object is correctly initialized
 116 ///  to be sent over the CAN bus
 117 ///
 118 /// @return True if object correctly initialized and false if not.
 119 bool can_message_t::is_correct_to_send()
 120 {
 121         if (id_ != 0 && length_ != 0 && format_ != can_message_format_t::INVALID)
 122         {
 123                 int i;
 124                 for(i=0;i<CAN_MESSAGE_SIZE;i++)
 125                         if(data_[i] != 0)
 126                                 return true;
 127         }
 128         return false;
 129 }
 130
 131 /// @brief Take a canfd_frame struct to initialize class members
 132 ///
 133 /// This is the preferred way to initialize class members.
 134 ///
 135 /// @param[in] frame - canfd_frame to convert coming from a read of CAN socket
 136 /// @param[in] nbytes - bytes read from socket read operation.
 137 ///
 138 /// @return A can_message_t object fully initialized with canfd_frame values.
 139 can_message_t can_message_t::convert_from_frame(const struct canfd_frame& frame, size_t nbytes, uint64_t timestamp)
 140 {
 141         uint8_t maxdlen = 0, length = 0, flags = 0;
 142         uint32_t id;
 143         can_message_format_t format;
 144         bool rtr_flag;
 145         std::vector<uint8_t> data;
 146
 147         switch(nbytes)
 148         {
 149                 case CANFD_MTU:
 150                         AFB_DEBUG("Got an CAN FD frame");
 151                         maxdlen = CANFD_MAX_DLEN;
 152                         break;
 153                 case CAN_MTU:
 154                         AFB_DEBUG("Got a legacy CAN frame");
 155                         maxdlen = CAN_MAX_DLEN;
 156                         break;
 157                 default:
 158                         AFB_ERROR("unsupported CAN frame");
 159                         break;
 160         }
 161
 162         if (frame.can_id & CAN_ERR_FLAG)
 163         {
 164                 format = can_message_format_t::INVALID;
 165                 id = frame.can_id & (CAN_ERR_MASK|CAN_ERR_FLAG);
 166         }
 167         else if (frame.can_id & CAN_EFF_FLAG)
 168         {
 169                 format = can_message_format_t::EXTENDED;
 170                 id = frame.can_id & CAN_EFF_MASK;
 171         }
 172         else
 173         {
 174                 format = can_message_format_t::STANDARD;
 175                 id = frame.can_id & CAN_SFF_MASK;
 176         }
 177
 178         /* Overwrite length_ if RTR flags is detected.
 179          * standard CAN frames may have RTR enabled. There are no ERR frames with RTR */
 180         if (frame.can_id & CAN_RTR_FLAG)
 181         {
 182                 rtr_flag = true;
 183                 if(frame.len && frame.len <= CAN_MAX_DLC)
 184                 {
 185                         if(rtr_flag)
 186                                 length = frame.len& 0xF;
 187                         else
 188                         {
 189                                 length = (frame.len > maxdlen) ? maxdlen : frame.len;
 190                         }
 191                 }
 192         }
 193         else
 194         {
 195                 length = (frame.len > maxdlen) ? maxdlen : frame.len;
 196
 197                 /* Flags field only present for CAN FD frames*/
 198                 if(maxdlen == CANFD_MAX_DLEN)
 199                                 flags = frame.flags & 0xF;
 200
 201                 if (data.capacity() < maxdlen)
 202                         data.reserve(maxdlen);
 203                                 int i;
 204
 205                         data.clear();
 206                         /* maxdlen_ is now set at CAN_MAX_DLEN or CANFD_MAX_DLEN, respectively 8 and 64 bytes*/
 207                         for(i=0;i<maxdlen;i++)
 208                         {
 209                                 data.push_back(frame.data[i]);
 210                         };
 211
 212                 AFB_DEBUG("Found id: %X, format: %X, length: %X, data %02X%02X%02X%02X%02X%02X%02X%02X",
 213                                                                 id, (uint8_t)format, length, data[0], data[1], data[2], data[3], data[4], data[5], data[6], data[7]);
 214         }
 215
 216         return can_message_t(maxdlen, id, length, format, rtr_flag, flags, data, timestamp);
 217 }