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/*
* 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 "can-message-definition.hpp"
#include "../binding/low-can-hat.hpp"
/// @brief Write a value into a CAN signal in the destination buffer.
///
/// @param[in] signal - The CAN signal to write, including the bit position and bit size.
/// @param[in] value - The encoded integer value to write into the CAN signal.
/// @param[out] data - The destination buffer.
/// @param[in] length - The length of the destination buffer.
///
/// @return Returns a can_frame struct initialized and ready to be send.
const can_frame build_frame(const can_signal_t& signal, uint64_t value)
{
struct can_frame cf;
::memset(&cf, 0, sizeof(cf));
cf.can_id = signal.get_message()->get_id();
cf.can_dlc = CAN_MAX_DLEN;
bitfield_encode_float((float)value,
signal.get_bit_position(),
signal.get_bit_size(),
signal.get_factor(),
signal.get_offset(),
cf.data,
CAN_MAX_DLEN);
return cf;
}
/// @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 can_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 can_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 can_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 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[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( can_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;
}
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