diff options
Diffstat (limited to 'low-can-binding/can/can-decoder.cpp')
| -rw-r--r-- | low-can-binding/can/can-decoder.cpp | 73 |
1 files changed, 66 insertions, 7 deletions
diff --git a/low-can-binding/can/can-decoder.cpp b/low-can-binding/can/can-decoder.cpp index e901240b..19594afa 100644 --- a/low-can-binding/can/can-decoder.cpp +++ b/low-can-binding/can/can-decoder.cpp @@ -23,6 +23,66 @@ #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. /// @@ -49,16 +109,12 @@ float decoder_t::parse_signal_bitfield(signal_t& signal, std::shared_ptr<message for(int i=new_start_byte;i<=new_end_byte;i++) data_signal.push_back(data[i]); -// if(bit_size > 255) -// AFB_ERROR("Error signal %s to long bit size", signal.get_name().c_str()); - -// if(new_start_bit > 255) -// AFB_ERROR("Too long signal offset %d", new_start_bit); + 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 bitfield_parse_float(data_signal.data(), (uint16_t) data_signal.size(), + 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()); } @@ -294,7 +350,10 @@ openxc_DynamicField decoder_t::decode_state(signal_t& signal, std::shared_ptr<me /// 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.set_bit_position(converter_t::bit_position_swap(signal.get_bit_position(),signal.get_bit_size())); + } // 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, |