2 * Copyright (C) 2015, 2016 "IoT.bzh"
3 * Author "Romain Forlot" <romain.forlot@iot.bzh>
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
9 * http://www.apache.org/licenses/LICENSE-2.0
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.
18 #include "can-decoder.hpp"
21 #include "canutil/read.h"
22 #include "../utils/openxc-utils.hpp"
23 #include "message-definition.hpp"
24 #include "../binding/low-can-hat.hpp"
25 #include "../utils/converter.hpp"
27 /// @brief Handle sign of the signal according to several decoding methods
29 /// @param[in] signal - The signal
30 /// @param[in] data_signal - The data of the signal
31 /// @param[in] new_end_bit - The last bit of in the last byte of the data (data_signal[0])
32 /// @param[in] can_data - The whole can data (needed for SIGN BIT EXTERN)
34 /// @return Returns the sign of the data
36 int decoder_t::handle_sign(const signal_t& signal, std::vector<uint8_t>& data_signal, uint8_t new_end_bit, const std::vector<uint8_t>& can_data)
38 uint8_t data_byte = 0;
42 if(signal.get_sign() == sign_t::UNSIGNED)
44 else if(signal.get_sign() == sign_t::SIGN_BIT_EXTERN) {
45 end_bit = signal.get_bit_sign_position() % CHAR_BIT;
46 mask = static_cast<uint8_t>((1 << (end_bit + 1)) - 1);
47 data_byte = can_data[signal.get_bit_sign_position() / CHAR_BIT] & mask;
50 end_bit = new_end_bit;
51 mask = static_cast<uint8_t>((1 << (end_bit + 1)) - 1);
52 data_byte = data_signal[0] & mask;
55 //if negative: decode with right method
56 if(data_byte >> end_bit) {
57 switch(signal.get_sign())
59 //remove the sign bit to get the absolute value
60 case sign_t::SIGN_BIT:
61 data_signal[0] = static_cast<uint8_t>(data_signal[0] & (mask >> 1));
63 //same method twos complement = ones complement + 1
64 case sign_t::ONES_COMPLEMENT:
65 case sign_t::TWOS_COMPLEMENT:
66 //complement only until end_bit
67 data_signal[0] = ((data_signal[0] ^ mask) & mask);
68 if(data_signal.size() > 1) {
69 for(int i=1; i < data_signal.size(); i++) {
70 data_signal[i] = data_signal[i] ^ 0xFF;
73 if(signal.get_sign() == sign_t::TWOS_COMPLEMENT)
74 data_signal[data_signal.size() - 1] = static_cast<uint8_t>(data_signal[data_signal.size() - 1] + 1);
76 case sign_t::SIGN_BIT_EXTERN:
79 AFB_ERROR("Not a valid sign entry %d, considering the value as unsigned", signal.get_sign());
87 /// @brief Parses the signal's bitfield from the given data and returns the raw
90 /// @param[in] signal - The signal to be parsed from the data.
91 /// @param[in] message - message_t to parse
93 /// @return Returns the raw value of the signal parsed as a bitfield from the given byte
96 float decoder_t::parse_signal_bitfield(signal_t& signal, std::shared_ptr<message_t> message)
99 std::vector<uint8_t> data;
100 std::vector<uint8_t> data_signal;
101 uint8_t bit_size = (uint8_t) signal.get_bit_size();
102 uint32_t bit_position = signal.get_bit_position();
104 int new_start_byte = 0;
105 int new_end_byte = 0;
106 uint8_t new_start_bit = 0;
107 uint8_t new_end_bit = 0;
109 if(signal.get_message()->get_flags() & CONTINENTAL_BIT_POSITION)
110 bit_position = converter_t::continental_bit_position_mess(message->get_length(),
111 signal.get_bit_position(),
113 if(signal.get_message()->get_flags() & BIT_POSITION_REVERSED)
114 bit_position = converter_t::bit_position_swap(message->get_length(),
115 signal.get_bit_position(),
117 if(signal.get_message()->get_flags() & FRAME_LAYOUT_IS_BIGENDIAN)
118 message->frame_swap();
120 data = message->get_data_vector();
121 converter_t::signal_to_bits_bytes(bit_position, bit_size, new_start_byte, new_end_byte, new_start_bit, new_end_bit);
123 for(int i=new_start_byte;i<=new_end_byte;i++)
124 data_signal.push_back(data[i]);
126 sign = handle_sign(signal, data_signal, new_end_bit, data);
128 if(data_signal.size() > 65535)
129 AFB_ERROR("Too long data signal %s", signal.get_name().c_str());
131 return static_cast<float>(sign) * bitfield_parse_float(data_signal.data(), (uint16_t) data_signal.size(),
132 new_start_bit, bit_size, signal.get_factor(),
133 signal.get_offset());
137 /// @brief Decode and return string bytes (hex) for a CAN signal's.
139 /// This is an implementation of the Signal type signature, and can be
140 /// used directly in the signal_t.decoder field.
142 /// @param[in] signal - The details of the signal.
143 /// @param[in] message - The message with data to decode.
144 /// @param[out] send - An output argument that will be set to false if the value should
145 /// not be sent for any reason.
147 /// @return Returns a DynamicField with a string value of bytes (hex)
149 openxc_DynamicField decoder_t::decode_bytes(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
152 openxc_DynamicField decoded_value;
153 std::vector<uint8_t> data = message->get_data_vector();
154 uint32_t length = message->get_length();
155 uint32_t bit_position = signal.get_bit_position();
156 uint32_t bit_size = signal.get_bit_size();
158 std::vector<uint8_t> new_data = std::vector<uint8_t>();
159 new_data.reserve((bit_size / CHAR_BIT) + 1);
161 int new_start_byte = 0;
162 int new_end_byte = 0;
163 uint8_t new_start_bit = 0;
164 uint8_t new_end_bit = 0;
166 converter_t::signal_to_bits_bytes(bit_position, bit_size, new_start_byte, new_end_byte, new_start_bit, new_end_bit);
168 if(new_end_byte >= length)
169 new_end_byte = length-1;
171 if(new_start_byte >= length)
173 AFB_ERROR("Error in signal's description");
174 return decoded_value;
177 uint8_t mask_first_v = static_cast<uint8_t>(0xFF << new_start_bit);
178 uint8_t mask_last_v = static_cast<uint8_t>(0xFF >> (7 - new_end_bit));
180 if(new_start_byte == new_end_byte)
182 data[new_start_byte] = data[new_start_byte] & (mask_first_v & mask_last_v);
186 data[new_start_byte] = data[new_start_byte] & mask_first_v;
187 data[new_end_byte] = data[new_end_byte] & mask_last_v;
190 for(i=new_start_byte ; i <= new_end_byte ; i++)
191 new_data.push_back(data[i]);
193 decoded_value = build_DynamicField(new_data);
195 return decoded_value;
199 /// @brief Decode and return string bytes (hex) for a CAN signal's.
201 /// This is an implementation of the Signal type signature, and can be
202 /// used directly in the signal_t.decoder field.
204 /// @param[in] signal - The details of the signal.
205 /// @param[in] message - The message with data to decode.
206 /// @param[out] send - An output argument that will be set to false if the value should
207 /// not be sent for any reason.
209 /// @return Returns a DynamicField with a string value of bytes (hex)
211 openxc_DynamicField decoder_t::decode_ascii(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
213 std::string ret_s = "";
214 openxc_DynamicField openxc_bytes = decode_bytes(signal,message,send);
215 if(!openxc_bytes.has_bytes_value)
217 AFB_ERROR("Error no bytes value to translate to ascii");
219 ret_s = converter_t::to_ascii(openxc_bytes.bytes_value,openxc_bytes.length_array);
220 openxc_DynamicField ret = build_DynamicField(ret_s);
225 openxc_DynamicField decoder_t::decode_date(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
227 float value = decoder_t::parse_signal_bitfield(signal, message);
228 AFB_DEBUG("Decoded message from parse_signal_bitfield: %f", value);
229 openxc_DynamicField decoded_value = build_DynamicField(value);
231 // Don't send if they is no changes
232 if ((signal.get_last_value() == value && !signal.get_send_same()) || !*send )
236 signal.set_last_value(value);
238 return decoded_value;
242 openxc_DynamicField decoder_t::decode_time(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
244 float value = decoder_t::parse_signal_bitfield(signal, message);
245 AFB_DEBUG("Decoded message from parse_signal_bitfield: %f", value);
246 openxc_DynamicField decoded_value = build_DynamicField(value);
248 // Don't send if they is no changes
249 if ((signal.get_last_value() == value && !signal.get_send_same()) || !*send )
253 signal.set_last_value(value);
255 return decoded_value;
259 /// @brief Wraps a raw CAN signal value in a DynamicField without modification.
261 /// This is an implementation of the Signal type signature, and can be
262 /// used directly in the signal_t.decoder field.
264 /// @param[in] signal - The details of the signal that contains the state mapping.
265 /// @param[in] message - The message with data to decode.
266 /// @param[out] send - An output argument that will be set to false if the value should
267 /// not be sent for any reason.
269 /// @return Returns a DynamicField with the original, unmodified raw CAN signal value as
270 /// its numeric value. The 'send' argument will not be modified as this decoder
273 openxc_DynamicField decoder_t::decode_noop(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
275 float value = decoder_t::parse_signal_bitfield(signal, message);
276 AFB_DEBUG("Decoded message from parse_signal_bitfield: %f", value);
277 openxc_DynamicField decoded_value = build_DynamicField(value);
279 // Don't send if they is no changes
280 if ((signal.get_last_value() == value && !signal.get_send_same()) || !*send )
284 signal.set_last_value(value);
286 return decoded_value;
288 /// @brief Coerces a numerical value to a boolean.
290 /// This is an implementation of the Signal type signature, and can be
291 /// used directly in the signal_t.decoder field.
293 /// @param[in] signal - The details of the signal that contains the state mapping.
294 /// @param[in] message - The message with data to decode.
295 /// @param[out] send - An output argument that will be set to false if the value should
296 /// not be sent for any reason.
298 /// @return Returns a DynamicField with a boolean value of false if the raw signal value
299 /// is 0.0, otherwise true. The 'send' argument will not be modified as this
300 /// decoder always succeeds.
302 openxc_DynamicField decoder_t::decode_boolean(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
304 float value = decoder_t::parse_signal_bitfield(signal, message);
305 AFB_DEBUG("Decoded message from parse_signal_bitfield: %f", value);
306 openxc_DynamicField decoded_value = build_DynamicField(value == 0.0 ? false : true);
308 // Don't send if they is no changes
309 if ((signal.get_last_value() == value && !signal.get_send_same()) || !*send )
312 signal.set_last_value(value);
315 return decoded_value;
317 /// @brief Update the metadata for a signal and the newly received value.
319 /// This is an implementation of the Signal type signature, and can be
320 /// used directly in the signal_t.decoder field.
322 /// This function always flips 'send' to false.
324 /// @param[in] signal - The details of the signal that contains the state mapping.
325 /// @param[in] message - The message with data to decode.
326 /// @param[out] send - This output argument will always be set to false, so the caller will
327 /// know not to publish this value to the pipeline.
329 /// @return Return value is undefined.
331 openxc_DynamicField decoder_t::decode_ignore(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
333 float value = decoder_t::parse_signal_bitfield(signal, message);
337 signal.set_last_value(value);
338 openxc_DynamicField decoded_value;
340 return decoded_value;
343 /// @brief Find and return the corresponding string state for a CAN signal's
344 /// raw integer value.
346 /// This is an implementation of the Signal type signature, and can be
347 /// used directly in the signal_t.decoder field.
349 /// @param[in] signal - The details of the signal that contains the state mapping.
350 /// @param[in] message - The message with data to decode.
351 /// @param[out] send - An output argument that will be set to false if the value should
352 /// not be sent for any reason.
354 /// @return Returns a DynamicField with a string value if a matching state is found in
355 /// the signal. If an equivalent isn't found, send is sent to false and the
356 /// return value is undefined.
358 openxc_DynamicField decoder_t::decode_state(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
360 float value = decoder_t::parse_signal_bitfield(signal, message);
361 AFB_DEBUG("Decoded message from parse_signal_bitfield: %f", value);
362 const std::string signal_state = signal.get_states((uint8_t)value);
363 openxc_DynamicField decoded_value = build_DynamicField(signal_state);
364 if(signal_state.size() <= 0)
367 AFB_ERROR("No state found with index: %d", (int)value);
370 // Don't send if they is no changes
371 if ((signal.get_last_value() == value && !signal.get_send_same()) || !*send )
375 signal.set_last_value(value);
378 return decoded_value;
382 /// @brief Parse a signal from a CAN message, apply any required transforations
383 /// to get a human readable value and public the result to the pipeline.
385 /// If the signal_t has a non-NULL 'decoder' field, the raw CAN signal value
386 /// will be passed to the decoder before publishing.
388 /// @param[in] signal - The details of the signal to decode and forward.
389 /// @param[in] message - The message with data to decode.
390 /// @param[out] send - An output parameter that will be flipped to false if the value could
393 /// The decoder returns an openxc_DynamicField, which may contain a number,
394 /// string or boolean.
396 openxc_DynamicField decoder_t::translate_signal(signal_t& signal, std::shared_ptr<message_t> message, bool* send)
398 // Must call the decoders every time, regardless of if we are going to
399 // decide to send the signal or not.
400 openxc_DynamicField decoded_value = decoder_t::decode_signal(signal,
403 signal.set_received(true);
404 signal.set_timestamp(message->get_timestamp());
405 signal.get_message()->set_last_value(message);
406 return decoded_value;
409 /// @brief Parse a signal from a CAN message and apply any required
410 /// transforations to get a human readable value.
412 /// If the signal_t has a non-NULL 'decoder' field, the raw CAN signal value
413 /// will be passed to the decoder before returning.
415 /// @param[in] signal - The details of the signal to decode and forward.
416 /// @param[in] message - The message with data to decode.
417 /// @param[out] send - An output parameter that will be flipped to false if the value could
420 /// @return The decoder returns an openxc_DynamicField, which may contain a number,
421 /// string or boolean. If 'send' is false, the return value is undefined.
423 openxc_DynamicField decoder_t::decode_signal( signal_t& signal, std::shared_ptr<message_t> message, bool* send)
425 signal_decoder decoder = signal.get_decoder() == nullptr ?
426 decode_noop : signal.get_decoder();
428 openxc_DynamicField decoded_value = decoder(signal,
430 return decoded_value;
434 /// @brief Decode the payload of an OBD-II PID.
436 /// This function matches the type signature for a DiagnosticResponse, so
437 /// it can be used as the decoder for a DiagnosticRequest. It returns the decoded
438 /// value of the PID, using the standard formulas (see
439 /// http://en.wikipedia.org/wiki/OBD-II_PIDs#Mode_01).
441 /// @param[in] response - the received DiagnosticResponse (the data is in response.payload,
442 /// a byte array). This is most often used when the byte order is
443 /// signiticant, i.e. with many OBD-II PID formulas.
444 /// @param[in] parsed_payload - the entire payload of the response parsed as an int.
446 /// @return Float decoded value.
448 float decoder_t::decode_obd2_response(const DiagnosticResponse* response, float parsed_payload)
450 return diagnostic_decode_obd2_pid(response);