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Diffstat (limited to 'low-can-binding/can/can-decoder.cpp')
| -rw-r--r-- | low-can-binding/can/can-decoder.cpp | 244 |
1 files changed, 244 insertions, 0 deletions
diff --git a/low-can-binding/can/can-decoder.cpp b/low-can-binding/can/can-decoder.cpp new file mode 100644 index 0000000..61bfe75 --- /dev/null +++ b/low-can-binding/can/can-decoder.cpp @@ -0,0 +1,244 @@ +/* + * 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 "can-message-definition.hpp" +#include "../binding/low-can-hat.hpp" + +/// @brief Parse the signal's bitfield from the given data and return the raw +/// value. +/// +/// @param[in] signal - The signal to parse from the data. +/// @param[in] message - can_message_t to parse +/// +/// @return Returns the raw value of the signal parsed as a bitfield from the given byte +/// array. +/// +float decoder_t::parseSignalBitfield(can_signal_t& signal, const can_message_t& message) +{ + return bitfield_parse_float(message.get_data(), CAN_MESSAGE_SIZE, + signal.get_bit_position(), signal.get_bit_size(), signal.get_factor(), + signal.get_offset()); +} + +/// @brief Wrap a raw CAN signal value in a DynamicField without modification. +/// +/// This is an implementation of the SignalDecoder type signature, and can be +/// used directly in the can_signal_t.decoder field. +/// +/// @param[in] signal - The details of the signal that contains the state mapping. +/// @param[in] signals - The list of all signals +/// @param[in] value - The numerical value that will be wrapped in a DynamicField. +/// @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::noopDecoder(can_signal_t& signal, + const std::vector<std::shared_ptr<can_signal_t> >& signals, float value, bool* send) +{ + openxc_DynamicField decoded_value = build_DynamicField(value); + + return decoded_value; +} +/// @brief Coerces a numerical value to a boolean. +/// +/// This is an implementation of the SignalDecoder type signature, and can be +/// used directly in the can_signal_t.decoder field. +/// +/// @param[in] signal - The details of the signal that contains the state mapping. +/// @param[in] signals - The list of all signals +/// @param[in] value - The numerical value that will be converted to a boolean. +/// @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::booleanDecoder(can_signal_t& signal, + const std::vector<std::shared_ptr<can_signal_t> >& signals, float value, bool* send) +{ + openxc_DynamicField decoded_value = build_DynamicField(value == 0.0 ? false : true); + + return decoded_value; +} +/// @brief Update the metadata for a signal and the newly received value. +/// +/// This is an implementation of the SignalDecoder type signature, and can be +/// used directly in the can_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] signals - The list of all signals. +/// @param[in] value - The numerical value that will be converted to a boolean. +/// @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::ignoreDecoder(can_signal_t& signal, + const std::vector<std::shared_ptr<can_signal_t> >& signals, float value, bool* send) +{ + if(send) + *send = false; + + 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 SignalDecoder type signature, and can be +/// used directly in the can_signal_t.decoder field. +/// +/// @param[in] signal - The details of the signal that contains the state mapping. +/// @param[in] signals - The list of all signals. +/// @param[in] value - The numerical value that should map to a state. +/// @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::stateDecoder(can_signal_t& signal, + const std::vector<std::shared_ptr<can_signal_t> >& signals, float value, bool* send) +{ + 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; + ERROR("No state found with index: %d", (int)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 can_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 received CAN message that should contain this signal. +/// @param[in] signals - an array of all active signals. +/// @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::translateSignal(can_signal_t& signal, const can_message_t& message, + const std::vector<std::shared_ptr<can_signal_t> >& signals, bool* send) +{ + float value = decoder_t::parseSignalBitfield(signal, message); + DEBUG("Decoded message from parseSignalBitfield: %f", value); + + // 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::decodeSignal(signal, + value, signals, send); + + signal.set_received(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); + 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 can_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] value - The numerical value that will be converted to a boolean. +/// @param[in] signals - an array of all active signals. +/// @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::decodeSignal( can_signal_t& signal, + float value, const std::vector<std::shared_ptr<can_signal_t> >& signals, bool* send) +{ + SignalDecoder decoder = signal.get_decoder() == nullptr ? + noopDecoder : signal.get_decoder(); + openxc_DynamicField decoded_value = decoder(signal, signals, + value, send); + return decoded_value; +} + +/// @brief Decode a transformed, human readable value from an raw CAN signal +/// already parsed from a CAN message. +/// +/// This is the same as decodeSignal but you must parse the bitfield value of the signal from the CAN +/// message yourself. This is useful if you need that raw value for something +/// else. +/// +/// @param[in] signal - The details of the signal to decode and forward. +/// @param[in] message - Raw CAN message to decode +/// @param[in] signals - an array of all active signals. +/// @param[out] send - An output parameter that will be flipped to false if the value could +/// not be decoded. +/// +openxc_DynamicField decoder_t::decodeSignal( can_signal_t& signal, + const can_message_t& message, const std::vector<std::shared_ptr<can_signal_t> >& signals, bool* send) +{ + float value = parseSignalBitfield(signal, message); + return decodeSignal(signal, value, signals, send); +} + + +/// +/// @brief Decode the payload of an OBD-II PID. +/// +/// This function matches the type signature for a DiagnosticResponseDecoder, 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); +}
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