path: root/low-can-binding/can/can-encoder.cpp

/*
 * 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-encoder.hpp"

#include "canutil/write.h"
#include "../utils/openxc-utils.hpp"
#include "message-definition.hpp"
#include "../utils/converter.hpp"

/**
 * @brief Allows to encode data for a signal
 *
 * @param sig The signal to know its location
 * @param data The data to encod
 * @param filter If true that will generate the filter BCM for the signal
 * @param factor If true that will use the factor of the signal else 1
 * @param offset If true that will use the offset of the signal else 0
 */
void encoder_t::encode_data(std::shared_ptr<signal_t> sig, std::vector<uint8_t> &data, bool filter, bool factor, bool offset)
{
	uint32_t bit_size = sig->get_bit_size();
	uint32_t bit_position = sig->get_bit_position();
	int new_start_byte = 0;
	int new_end_byte = 0;
	int new_start_bit_tmp = 0;
	int new_end_bit = 0;

	converter_t::signal_to_bits_bytes(bit_position, bit_size, new_start_byte, new_end_byte, new_start_bit_tmp, new_end_bit);

	int len_signal_bytes_tmp = new_end_byte - new_start_byte + 1;

	uint8_t len_signal_bytes = 0;
	if(len_signal_bytes_tmp > 255)
	{
		AFB_ERROR("Error signal %s too long",sig->get_name().c_str());
	}
	else
	{
		len_signal_bytes = (uint8_t) len_signal_bytes_tmp;
	}

	uint8_t new_start_bit = 0;
	if(new_start_bit_tmp > 255)
	{
		AFB_ERROR("Error signal %s too long",sig->get_name().c_str());
	}
	else
	{
		new_start_bit = (uint8_t) new_start_bit_tmp;
	}

	uint8_t new_bit_size = 0;
	if(bit_size > 255)
	{
		AFB_ERROR("Error signal %s to long bit size",sig->get_name().c_str());
	}
	else
	{
		new_bit_size = (uint8_t) bit_size;
	}

	uint8_t data_signal[len_signal_bytes] = {0};
	float factor_v = 1;
	if(factor)
	{
		factor_v = sig->get_factor();
	}

	float offset_v = 0;
	if(factor)
	{
		offset_v = sig->get_offset();
	}

	if(filter)
	{
		uint8_t tmp = 0;
		int j=0;
		for(int i=0;i<new_bit_size;i++)
		{
			int mask = 0x80 >> ((i%8)+new_start_bit);

			uint8_t mask_v = 0;
			if(mask > 255)
			{
				AFB_ERROR("Error mask too large");
			}
			else
			{
				mask_v = (uint8_t) mask;
			}
			tmp = tmp|mask_v;

			if(i%8 == 7)
			{
				data_signal[j] = tmp;
				tmp = 0;
				j++;
			}
		}
		data_signal[j]=tmp;
	}
	else
	{
		bitfield_encode_float(	sig->get_last_value(),
						new_start_bit,
						new_bit_size,
						factor_v,
						offset_v,
						data_signal,
						len_signal_bytes);
	}

	for(size_t i = new_start_byte; i <= new_end_byte ; i++)
	{
		data[i] = data[i] | data_signal[i-new_start_byte];
	}
}

/**
 * @brief Allows to build a multi frame message with correct data to be send
 *
 * @param signal The CAN signal to write, including the bit position and bit size.
 * @param value The encoded integer value to write in the CAN signal.
 * @param message A multi frame message to complete
 * @param factor If true that will use the factor of the signal else 1
 * @param offset If true that will use the offset of the signal else 0
 * @return message_t*  The message that is generated
 */
message_t* encoder_t::build_frame(const std::shared_ptr<signal_t>& signal, uint64_t value, message_t *message, bool factor, bool offset)
{
	signal->set_last_value((float)value);
	std::vector<uint8_t> data;
	for(int i = 0; i<message->get_length();i++)
	{
		data.push_back(0);
	}

	for(const auto& sig: signal->get_message()->get_signals())
	{
		encode_data(sig,data,false,factor,offset);
	}
	message->set_data(data);
	return message;
}

/**
 * @brief Allows to build a message_t with correct data to be send
 *
 * @param signal The CAN signal to write, including the bit position and bit size.
 * @param value The encoded integer value to write in the CAN signal.
 * @param factor If true that will use the factor of the signal else 1
 * @param offset If true that will use the offset of the signal else 0
 * @return message_t* The message that is generated
 */
message_t* encoder_t::build_message(const std::shared_ptr<signal_t>& signal, uint64_t value, bool factor, bool offset)
{
	message_t *message;
	std::vector<uint8_t> data;
	if(signal->get_message()->is_fd())
	{
		message = new can_message_t( CANFD_MAX_DLEN,
									 signal->get_message()->get_id(),
									 CANFD_MAX_DLEN,
									 false,
									 signal->get_message()->get_flags(),
									 data,
									 0);

		return build_frame(signal,value,message, factor, offset);
	}
#ifdef USE_FEATURE_J1939
	else if(signal->get_message()->is_j1939())
	{
		message = new j1939_message_t( signal->get_message()->get_length(),
									   data,
									   0,
									   J1939_NO_NAME,
									   signal->get_message()->get_id(),
									   J1939_NO_ADDR);
		return build_frame(signal,value,message, factor, offset);
	}
#endif
	else
	{
		message = new can_message_t(CAN_MAX_DLEN,
									signal->get_message()->get_id(),
									CAN_MAX_DLEN,
									false,
									signal->get_message()->get_flags(),
									data,
									0);
		return build_frame(signal,value,message, factor, offset);
	}
}

/// @brief Encode a boolean into an integer, fit for a CAN signal bitfield.
///
/// This is a shortcut for encodeDynamicField(CanSignal*, openxc_DynamicField*,
/// bool*) that takes care of creating the DynamicField object for you with the
/// boolean value.
///
/// @param[in] signal  - The CAN signal to encode this value for..
/// @param[in] value - The boolean value to encode
/// @param[out] send - An output argument that will be set to false if the value should
///     not be sent for any reason.
///
/// @return Returns the encoded integer. If 'send' is changed to false, the field could
/// not be encoded and the return value is undefined.
///
uint64_t encoder_t::encode_boolean(const signal_t& signal, bool value, bool* send)
{
	return encode_number(signal, float(value), send);
}
/// @brief Encode a float into an integer, fit for a CAN signal's bitfield.
///
/// This is a shortcut for encodeDynamicField(CanSignal*, openxc_DynamicField*,
/// bool*) that takes care of creating the DynamicField object for you with the
/// float value.
///
/// @param[in] signal  - The CAN signal to encode this value for.
/// @param[in] value - The float value to encode.
/// @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 Returns the encoded integer. If 'send' is changed to false, the field could
/// not be encoded and the return value is undefined.
///
uint64_t encoder_t::encode_number(const signal_t& signal, float value, bool* send)
{
	return float_to_fixed_point(value, signal.get_factor(), signal.get_offset());
}

/// @brief Encode a string into an integer, fit for a CAN signal's bitfield.
///
/// Be aware that the behavior is undefined if there are multiple values assigned
/// to a single state. See https://github.com/openxc/vi-firmware/issues/185.
///
/// This is a shortcut for encodeDynamicField(CanSignal*, openxc_DynamicField*,
/// bool*) that takes care of creating the DynamicField object for you with the
/// string state value.
///
/// @param[in] signal  - The details of the signal that contains the state mapping.
/// @param[in] value - The string state value to encode.
/// @param[out] send - An output argument that will be set to false if the value should
///     not be sent for any reason.
///
/// @return Returns the encoded integer. If 'send' is changed to false, the field could
/// not be encoded and the return value is undefined.
///
uint64_t encoder_t::encode_state(const signal_t& signal, const std::string& state, bool* send)
{
	uint64_t value = 0;
	if(state == "")
	{
		AFB_DEBUG("Can't write state of "" -- not sending");
		*send = false;
	}
	else
	{
		uint64_t signal_state = signal.get_states(state);
		if(signal_state != -1) {
			value = signal_state;
		} else {
			AFB_DEBUG("Couldn't find a valid signal state for %s", state.c_str());
			*send = false;
		}
	}
	return 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] value - The numerical value that will be converted to a boolean.
/// @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.
///
uint64_t encoder_t::encode_DynamicField( signal_t& signal, const openxc_DynamicField& field, bool* send)
{
	uint64_t value = 0;
	switch(field.type) {
		case openxc_DynamicField_Type_STRING:
			value = encode_state(signal, field.string_value, send);
			break;
		case openxc_DynamicField_Type_NUM:
			value = encode_number(signal, (float)field.numeric_value, send);
			break;
		case openxc_DynamicField_Type_BOOL:
			value = encode_boolean(signal, field.boolean_value, send);
			break;
		default:
			AFB_DEBUG("Dynamic field didn't have a value, can't encode");
			*send = false;
			break;
	}
	return value;
}