src/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 "../low-can-binding.hpp"
  23
  24 /**
  25 * @brief Class constructor
  26 *
  27 * Constructor about can_message_t class.
  28 */
  29 can_message_t::can_message_t()
  30         : maxdlen_{0}, id_{0}, length_{0}, format_{can_message_format_t::ERROR}, rtr_flag_{false}, flags_{0}
  31 {}
  32
  33 can_message_t::can_message_t(uint8_t maxdlen, uint32_t id, uint8_t length, can_message_format_t format, bool rtr_flag, uint8_t flags, std::vector<uint8_t> data)
  34         :  maxdlen_{maxdlen}, id_{id}, length_{length}, format_{format}, rtr_flag_{rtr_flag}, flags_{flags}, data_{data}
  35 {}
  36
  37 /**
  38 * @brief Retrieve id_ member value.
  39 *
  40 * @return id_ class member
  41 */
  42 uint32_t can_message_t::get_id() const
  43 {
  44         return id_;
  45 }
  46
  47 /**
  48 * @brief Retrieve RTR flag member.
  49 *
  50 * @return rtr_flags_ class member
  51 */
  52 bool can_message_t::get_rtr_flag_() const
  53 {
  54         return rtr_flag_;
  55 }
  56
  57 /**
  58 * @brief Retrieve format_ member value.
  59 *
  60 * @return format_ class member
  61 */
  62 can_message_format_t can_message_t::get_format() const
  63 {
  64         if (format_ != can_message_format_t::STANDARD || format_ != can_message_format_t::EXTENDED)
  65                 return can_message_format_t::ERROR;
  66         return format_;
  67 }
  68
  69 /**
  70 * @brief Retrieve flags_ member value.
  71 *
  72 * @return flags_ class member
  73 */
  74 uint8_t can_message_t::get_flags() const
  75 {
  76         return flags_;
  77 }
  78
  79 /**
  80 * @brief Retrieve data_ member value.
  81 *
  82 * @return pointer to the first element
  83 *  of class member data_
  84 */
  85 const uint8_t* can_message_t::get_data() const
  86 {
  87         return data_.data();
  88 }
  89
  90 /**
  91 * @brief Retrieve length_ member value.
  92 *
  93 * @return length_ class member
  94 */
  95 uint8_t can_message_t::get_length() const
  96 {
  97         return length_;
  98 }
  99
 100 /**
 101 * @brief Control whether the object is correctly initialized
 102 *  to be sent over the CAN bus
 103 *
 104 * @return true if object correctly initialized and false if not.
 105 */
 106 bool can_message_t::is_correct_to_send()
 107 {
 108         if (id_ != 0 && length_ != 0 && format_ != can_message_format_t::ERROR)
 109         {
 110                 int i;
 111                 for(i=0;i<CAN_MESSAGE_SIZE;i++)
 112                         if(data_[i] != 0)
 113                                 return true;
 114         }
 115         return false;
 116 }
 117
 118 /**
 119 * @brief Set format_ member value.
 120 *
 121 * Preferred way to initialize these members by using
 122 * convert_from_canfd_frame method.
 123 *
 124 * @param[in] new_format - class member
 125 */
 126 void can_message_t::set_format(const can_message_format_t new_format)
 127 {
 128         if(new_format == can_message_format_t::STANDARD || new_format == can_message_format_t::EXTENDED || new_format == can_message_format_t::ERROR)
 129                 format_ = new_format;
 130         else
 131                 ERROR(binder_interface, "ERROR: Can set format, wrong format chosen");
 132 }
 133
 134 /**
 135 * @brief Take a canfd_frame struct to initialize class members
 136 *
 137 * This is the preferred way to initialize class members.
 138 *
 139 * @param[in] frame - canfd_frame to convert coming from a read of CAN socket
 140 * @param[in] nbyte - bytes read from socket read operation.
 141 *
 142 * @return A can_message_t object fully initialized with canfd_frame values.
 143 */
 144 can_message_t can_message_t::convert_from_canfd_frame(const struct canfd_frame& frame, size_t nbytes)
 145 {
 146         uint8_t maxdlen, length, flags = (uint8_t)NULL;
 147         uint32_t id;
 148         can_message_format_t format;
 149         bool rtr_flag;
 150         std::vector<uint8_t> data;
 151
 152         switch(nbytes)
 153         {
 154                 case CANFD_MTU:
 155                         DEBUG(binder_interface, "set_max_data_length: Got an CAN FD frame");
 156                         maxdlen = CANFD_MAX_DLEN;
 157                         break;
 158                 case CAN_MTU:
 159                         DEBUG(binder_interface, "set_max_data_length: Got a legacy CAN frame");
 160                         maxdlen = CAN_MAX_DLEN;
 161                         break;
 162                 default:
 163                         ERROR(binder_interface, "set_max_data_length: unsupported CAN frame");
 164                         break;
 165         }
 166
 167         if (frame.can_id & CAN_ERR_FLAG)
 168                 format = can_message_format_t::ERROR;
 169         else if (frame.can_id & CAN_EFF_FLAG)
 170                 format = can_message_format_t::EXTENDED;
 171         else
 172                 format = can_message_format_t::STANDARD;
 173
 174         switch(format)
 175         {
 176                 case can_message_format_t::STANDARD:
 177                         id = frame.can_id & CAN_SFF_MASK;
 178                         break;
 179                 case can_message_format_t::EXTENDED:
 180                         id = frame.can_id & CAN_EFF_MASK;
 181                         break;
 182                 case can_message_format_t::ERROR:
 183                         id = frame.can_id & (CAN_ERR_MASK|CAN_ERR_FLAG);
 184                         break;
 185                 default:
 186                         ERROR(binder_interface, "ERROR: Can set id, not a compatible format or format not set prior to set id.");
 187                         break;
 188         }
 189
 190         /* Overwrite length_ if RTR flags is detected.
 191          * standard CAN frames may have RTR enabled. There are no ERR frames with RTR */
 192         if (frame.can_id & CAN_RTR_FLAG)
 193         {
 194                 rtr_flag = true;
 195                 if(frame.len && frame.len <= CAN_MAX_DLC)
 196                 {
 197                         if(rtr_flag)
 198                                 length = frame.len& 0xF;
 199                         else
 200                         {
 201                                 length = (frame.len > maxdlen) ? maxdlen : frame.len;
 202                         }
 203                 }
 204         }
 205         else
 206         {
 207                 length = (frame.len > maxdlen) ? maxdlen : frame.len;
 208
 209                 /* Flags field only present for CAN FD frames*/
 210                 if(maxdlen == CANFD_MAX_DLEN)
 211                                 flags = frame.flags & 0xF;
 212
 213                 if (data.capacity() < maxdlen)
 214                         data.reserve(maxdlen);
 215                                 int i;
 216
 217                         data.clear();
 218                         /* maxdlen_ is now set at CAN_MAX_DLEN or CANFD_MAX_DLEN, respectively 8 and 64 bytes*/
 219                         for(i=0;i<maxdlen;i++)
 220                         {
 221                                 data.push_back(frame.data[i]);
 222                         };
 223
 224                 DEBUG(binder_interface, "convert_from_canfd_frame: Found id: %X, format: %X, length: %X, data %02X%02X%02X%02X%02X%02X%02X%02X",
 225                                                                 id, format, length, data[0], data[1], data[2], data[3], data[4], data[5], data[6], data[7]);
 226         }
 227
 228         return can_message_t(maxdlen, id, length, format, rtr_flag, flags, data);
 229 }
 230
 231 /**
 232 * @brief Take all initialized class's members and build an
 233 * canfd_frame struct that can be use to send a CAN message over
 234 * the bus.
 235 *
 236 * @return canfd_frame struct built from class members.
 237 */
 238 canfd_frame can_message_t::convert_to_canfd_frame()
 239 {
 240         canfd_frame frame;
 241
 242         if(is_correct_to_send())
 243         {
 244                 frame.can_id = get_id();
 245                 frame.len = get_length();
 246                 ::memcpy(frame.data, get_data(), length_);
 247         }
 248         else
 249                 ERROR(binder_interface, "can_message_t not correctly initialized to be sent");
 250
 251         return frame;
 252 }