Implement more performant algorithm to get value for little endian

Author: Murmele

src/message.cpp

@@ -34,11 +34,8 @@ Message::ParseSignalsStatus Message::parseSignals(const std::vector<uint8_t>& da
 			uint32_t start_bit = 8 * (signal.start_bit / 8) + (7 - (signal.start_bit % 8)); // Calculation taken from python CAN
 			v = data_big_endian << start_bit;
 			v = v >> (len - signal.size);
-		} else {
-			const uint32_t shiftLeft = (len - (signal.size + signal.start_bit));
-			v = data_little_endian << shiftLeft;
-			v = v >> (shiftLeft + signal.start_bit);
-		}
+		} else
+			v = data_little_endian >> signal.start_bit;
 
 		if (signal.is_signed && signal.size > 1) {
 			switch (signal.size) {
@@ -61,14 +58,15 @@ Message::ParseSignalsStatus Message::parseSignals(const std::vector<uint8_t>& da
 				if (negative)
 					nativeInt = v | ~((1 << signal.size) - 1); // invert all bits above signal.size
 				else
-					nativeInt = v;
+					nativeInt = v & ((1 << signal.size) - 1); // masking
 				values.push_back(nativeInt * signal.factor + signal.offset);
 				break;
 			}
 			}
 		} else {
 			// use only the relevant bits
-			values.push_back((v & ((1 << signal.size) - 1)) * signal.factor + signal.offset);
+			v = v & ((1 << signal.size) - 1); // masking
+			values.push_back(v * signal.factor + signal.offset);
 		}
 	}
 	return ParseSignalsStatus::Success;