/* * Copyright (C) 2015, 2016 "IoT.bzh" * Author "Romain Forlot" <romain.forlot@iot.bzh> * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ #include "can-decoder.hpp" #include "canutil/read.h" #include "../utils/openxc-utils.hpp" #include "message-definition.hpp" #include "../binding/low-can-hat.hpp" #include "../utils/converter.hpp" /// @brief Handle sign of the signal according to several decoding methods /// /// @param[in] signal - The signal /// @param[in] data_signal - The data of the signal /// @param[in] new_end_bit - The last bit of in the last byte of the data (data_signal[0]) /// @param[in] can_data - The whole can data (needed for SIGN BIT EXTERN) /// /// @return Returns the sign of the data /// 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) { uint8_t data_byte = 0; uint8_t mask = 0; int end_bit = 0; if(signal.get_sign() == sign_t::UNSIGNED) return 1; else if(signal.get_sign() == sign_t::SIGN_BIT_EXTERN) { end_bit = signal.get_bit_sign_position()%8; mask = static_cast<uint8_t>((1 << (end_bit + 1)) - 1); data_byte = can_data[signal.get_bit_sign_position()/8] & mask; } else { end_bit = new_end_bit; mask = static_cast<uint8_t>((1 << (end_bit + 1)) - 1); data_byte = data_signal[0] & mask; } //if negative: decode with right method if(data_byte >> end_bit) { switch(signal.get_sign()) { //remove the sign bit to get the absolute value case sign_t::SIGN_BIT: data_signal[0] = static_cast<uint8_t>(data_signal[0] & (mask >> 1)); break; //same method twos complement = ones complement + 1 case sign_t::ONES_COMPLEMENT: case sign_t::TWOS_COMPLEMENT: //complement only until end_bit data_signal[0] = ((data_signal[0] ^ mask) & mask); if(data_signal.size() > 1) { for(int i=1; i < data_signal.size(); i++) { data_signal[i] = data_signal[i] ^ 0xFF; } } if(signal.get_sign() == sign_t::TWOS_COMPLEMENT) data_signal[data_signal.size() - 1] = static_cast<uint8_t>(data_signal[data_signal.size() - 1] + 1); break; case sign_t::SIGN_BIT_EXTERN: break; default: AFB_ERROR("Not a valid sign entry %d, considering the value as unsigned", signal.get_sign()); break; } return -1; } return 1; } /// @brief Parses the signal's bitfield from the given data and returns the raw /// value. /// /// @param[in] signal - The signal to be parsed from the data. /// @param[in] message - message_t to parse /// /// @return Returns the raw value of the signal parsed as a bitfield from the given byte /// array. /// float decoder_t::parse_signal_bitfield(signal_t& signal, std::shared_ptr<message_t> message) { const std::vector<uint8_t> data = message->get_data_vector(); std::vector<uint8_t> data_signal; uint8_t bit_size = (uint8_t) signal.get_bit_size(); uint32_t bit_position = signal.get_bit_position(); int new_start_byte = 0; int new_end_byte = 0; uint8_t new_start_bit = 0; uint8_t new_end_bit = 0; converter_t::signal_to_bits_bytes(bit_position, bit_size, new_start_byte, new_end_byte, new_start_bit, new_end_bit); for(int i=new_start_byte;i<=new_end_byte;i++) data_signal.push_back(data[i]); int sign = decoder_t::handle_sign(signal, data_signal, new_end_bit, data); if(data_signal.size() > 65535) AFB_ERROR("Too long data signal %s", signal.get_name().c_str()); return static_cast<float>(sign) * bitfield_parse_float(data_signal.data(), (uint16_t) data_signal.size(), new_start_bit, bit_size, signal.get_factor(), signal.get_offset()); } /// @brief Decode and return string bytes (hex) for a CAN signal's. /// /// This is an implementation of the Signal type signature, and can be /// used directly in the signal_t.decoder field. /// /// @param[in] signal - The details of the signal. /// @param[in] message - The message with data to decode. /// @param[out] send - An output argument that will be set to false if the value should /// not be sent for any reason. /// /// @return Returns a DynamicField with a string value of bytes (hex) /// openxc_DynamicField decoder_t::decode_bytes(signal_t& signal, std::shared_ptr<message_t> message, bool* send) { int i=0; openxc_DynamicField decoded_value; std::vector<uint8_t> data = message->get_data_vector(); uint32_t length = message->get_length(); uint32_t bit_position = signal.get_bit_position(); uint32_t bit_size = signal.get_bit_size(); std::vector<uint8_t> new_data = std::vector<uint8_t>(); new_data.reserve((bit_size / 8) + 1); int new_start_byte = 0; int new_end_byte = 0; uint8_t new_start_bit = 0; uint8_t new_end_bit = 0; converter_t::signal_to_bits_bytes(bit_position, bit_size, new_start_byte, new_end_byte, new_start_bit, new_end_bit); if(new_end_byte >= length) new_end_byte = length-1; if(new_start_byte >= length) { AFB_ERROR("Error in description of signals"); return decoded_value; } uint8_t mask_first_v = static_cast<uint8_t>(0xFF << new_start_bit); uint8_t mask_last_v = static_cast<uint8_t>(0xFF >> (7 - new_end_bit)); if(new_start_byte == new_end_byte) { data[new_start_byte] = data[new_start_byte] & (mask_first_v & mask_last_v); } else { data[new_start_byte] = data[new_start_byte] & mask_first_v; data[new_end_byte] = data[new_end_byte] & mask_last_v; } for(i=new_start_byte ; i <= new_end_byte ; i++) new_data.push_back(data[i]); decoded_value = build_DynamicField(new_data); return decoded_value; } /// @brief Wraps a raw CAN signal value in a DynamicField without modification. /// /// This is an implementation of the Signal type signature, and can be /// used directly in the signal_t.decoder field. /// /// @param[in] signal - The details of the signal that contains the state mapping. /// @param[in] message - The message with data to decode. /// @param[out] send - An output argument that will be set to false if the value should /// not be sent for any reason. /// /// @return Returns a DynamicField with the original, unmodified raw CAN signal value as /// its numeric value. The 'send' argument will not be modified as this decoder /// always succeeds. /// openxc_DynamicField decoder_t::decode_noop(signal_t& signal, std::shared_ptr<message_t> message, bool* send) { float value = decoder_t::parse_signal_bitfield(signal, message); AFB_DEBUG("Decoded message from parse_signal_bitfield: %f", value); openxc_DynamicField decoded_value = build_DynamicField(value); // Don't send if they is no changes if ((signal.get_last_value() == value && !signal.get_send_same()) || !*send ) { *send = false; } signal.set_last_value(value); return decoded_value; } /// @brief Coerces a numerical value to a boolean. /// /// This is an implementation of the Signal type signature, and can be /// used directly in the signal_t.decoder field. /// /// @param[in] signal - The details of the signal that contains the state mapping. /// @param[in] message - The message with data to decode. /// @param[out] send - An output argument that will be set to false if the value should /// not be sent for any reason. /// /// @return Returns a DynamicField with a boolean value of false if the raw signal value /// is 0.0, otherwise true. The 'send' argument will not be modified as this /// decoder always succeeds. /// openxc_DynamicField decoder_t::decode_boolean(signal_t& signal, std::shared_ptr<message_t> message, bool* send) { float value = decoder_t::parse_signal_bitfield(signal, message); AFB_DEBUG("Decoded message from parse_signal_bitfield: %f", value); openxc_DynamicField decoded_value = build_DynamicField(value == 0.0 ? false : true); // Don't send if they is no changes if ((signal.get_last_value() == value && !signal.get_send_same()) || !*send ) *send = false; signal.set_last_value(value); return decoded_value; } /// @brief Update the metadata for a signal and the newly received value. /// /// This is an implementation of the Signal type signature, and can be /// used directly in the signal_t.decoder field. /// /// This function always flips 'send' to false. /// /// @param[in] signal - The details of the signal that contains the state mapping. /// @param[in] message - The message with data to decode. /// @param[out] send - This output argument will always be set to false, so the caller will /// know not to publish this value to the pipeline. /// /// @return Return value is undefined. /// openxc_DynamicField decoder_t::decode_ignore(signal_t& signal, std::shared_ptr<message_t> message, bool* send) { float value = decoder_t::parse_signal_bitfield(signal, message); if(send) *send = false; signal.set_last_value(value); openxc_DynamicField decoded_value; return decoded_value; } /// @brief Find and return the corresponding string state for a CAN signal's /// raw integer value. /// /// This is an implementation of the Signal type signature, and can be /// used directly in the signal_t.decoder field. /// /// @param[in] signal - The details of the signal that contains the state mapping. /// @param[in] message - The message with data to decode. /// @param[out] send - An output argument that will be set to false if the value should /// not be sent for any reason. /// /// @return Returns a DynamicField with a string value if a matching state is found in /// the signal. If an equivalent isn't found, send is sent to false and the /// return value is undefined. /// openxc_DynamicField decoder_t::decode_state(signal_t& signal, std::shared_ptr<message_t> message, bool* send) { float value = decoder_t::parse_signal_bitfield(signal, message); AFB_DEBUG("Decoded message from parse_signal_bitfield: %f", value); const std::string signal_state = signal.get_states((uint8_t)value); openxc_DynamicField decoded_value = build_DynamicField(signal_state); if(signal_state.size() <= 0) { *send = false; AFB_ERROR("No state found with index: %d", (int)value); } // Don't send if they is no changes if ((signal.get_last_value() == value && !signal.get_send_same()) || !*send ) { *send = false; } signal.set_last_value(value); return decoded_value; } /// @brief Parse a signal from a CAN message, apply any required transforations /// to get a human readable value and public the result to the pipeline. /// /// If the signal_t has a non-NULL 'decoder' field, the raw CAN signal value /// will be passed to the decoder before publishing. /// /// @param[in] signal - The details of the signal to decode and forward. /// @param[in] message - The message with data to decode. /// @param[out] send - An output parameter that will be flipped to false if the value could /// not be decoded. /// /// The decoder returns an openxc_DynamicField, which may contain a number, /// string or boolean. /// openxc_DynamicField decoder_t::translate_signal(signal_t& signal, std::shared_ptr<message_t> message, bool* send) { if(!signal.get_message()->frame_layout_is_little() && !signal.bit_position_is_swapped()) { signal.set_bit_position(converter_t::bit_position_swap(signal.get_bit_position(),signal.get_bit_size())); signal.bit_position_is_swapped_reverse(); } // Must call the decoders every time, regardless of if we are going to // decide to send the signal or not. openxc_DynamicField decoded_value = decoder_t::decode_signal(signal, message, send); signal.set_received(true); signal.set_timestamp(message->get_timestamp()); signal.get_message()->set_last_value(message); return decoded_value; } /// @brief Parse a signal from a CAN message and apply any required /// transforations to get a human readable value. /// /// If the signal_t has a non-NULL 'decoder' field, the raw CAN signal value /// will be passed to the decoder before returning. /// /// @param[in] signal - The details of the signal to decode and forward. /// @param[in] message - The message with data to decode. /// @param[out] send - An output parameter that will be flipped to false if the value could /// not be decoded. /// /// @return The decoder returns an openxc_DynamicField, which may contain a number, /// string or boolean. If 'send' is false, the return value is undefined. /// openxc_DynamicField decoder_t::decode_signal( signal_t& signal, std::shared_ptr<message_t> message, bool* send) { signal_decoder decoder = signal.get_decoder() == nullptr ? decode_noop : signal.get_decoder(); openxc_DynamicField decoded_value = decoder(signal, message, send); return decoded_value; } /// /// @brief Decode the payload of an OBD-II PID. /// /// This function matches the type signature for a DiagnosticResponse, so /// it can be used as the decoder for a DiagnosticRequest. It returns the decoded /// value of the PID, using the standard formulas (see /// http://en.wikipedia.org/wiki/OBD-II_PIDs#Mode_01). /// /// @param[in] response - the received DiagnosticResponse (the data is in response.payload, /// a byte array). This is most often used when the byte order is /// signiticant, i.e. with many OBD-II PID formulas. /// @param[in] parsed_payload - the entire payload of the response parsed as an int. /// /// @return Float decoded value. /// float decoder_t::decode_obd2_response(const DiagnosticResponse* response, float parsed_payload) { return diagnostic_decode_obd2_pid(response); }