Parse non byte aligned number

CMakeLists.txt

@@ -14,6 +14,8 @@ include(CPack)
 
 option(DEBUG "use debug flag" NO)
 option(ENABLE_TESTS "Enable Unittests" ON)
+# Turn OFF, if you are using FetchContent to include it to your project
+option(FETCH_CONTENT_INCLUSION "Include project with FetchContent_Declare in another project. In this case the headers and the cmake files are not needed, only the library" OFF)
 
 # defines variables used in the dbc.pc.in
 include(GNUInstallDirs)
@@ -30,7 +32,9 @@ if (NOT ${FastFloat_FOUND})
       GIT_REPOSITORY https://github.com/fastfloat/fast_float.git
       GIT_TAG 1ea4f27b2aeee2859a1354a3c24cff52a116cad1
     )
-    FetchContent_MakeAvailable(FastFloat)
+    # FetchContent_MakeAvailable(FastFloat)
+    FetchContent_Populate(FastFloat)
+    add_subdirectory(${fastfloat_SOURCE_DIR} ${fastfloat_BINARY_DIR} EXCLUDE_FROM_ALL)
 endif()
 
 set(GCC_COMPILE_FLAGS "-Wextra -Wall -Wfloat-equal -Wundef -Wshadow \
@@ -92,18 +96,21 @@ install(TARGETS ${PROJECT_NAME}
 		DESTINATION ${CMAKE_INSTALL_LIBDIR})
 
 # install headers
-if (${CMAKE_MINOR_VERSION} GREATER_EQUAL 23)
+if (${CMAKE_MINOR_VERSION} GREATER_EQUAL 23 AND NOT FETCH_CONTENT_INCLUSION)
     install(TARGETS ${PROJECT_NAME}
                     FILE_SET HEADERS
                     DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/lib${PROJECT_NAME}
                     INCLUDES DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}
     )
-else()
+elseif(NOT FETCH_CONTENT_INCLUSION)
     install(DIRECTORY ${PROJECT_SOURCE_DIR}/include/libdbc DESTINATION ${CMAKE_INSTALL_INCLUDEDIR})
 endif()
 
-# Generate pkg-config file
-configure_file(${PROJECT_NAME}.pc.in ${PROJECT_NAME}.pc @ONLY)
-install(
-    FILES ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}.pc
-    DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+
+if (NOT FETCH_CONTENT_INCLUSION)
+    # Generate pkg-config file
+    configure_file(${PROJECT_NAME}.pc.in ${PROJECT_NAME}.pc @ONLY)
+    install(
+        FILES ${CMAKE_CURRENT_BINARY_DIR}/${PROJECT_NAME}.pc
+        DESTINATION ${CMAKE_INSTALL_LIBDIR}/pkgconfig)
+endif()

include/libdbc/message.hpp

@@ -31,6 +31,9 @@ struct Message {
 	void appendSignal(const Signal& signal);
 	const std::vector<Signal> getSignals() const;
 	uint32_t id() const;
+	const std::string& name() const {
+		return m_name;
+	}
 	void addValueDescription(const std::string& signal_name, const std::vector<Signal::SignalValueDescriptions>&);
 
 	virtual bool operator==(const Message& rhs) const;

include/libdbc/signal.hpp

@@ -2,6 +2,7 @@
 #ifndef __SIGNAL_HPP__
 #define __SIGNAL_HPP__
 
+#include <cstdint>
 #include <iostream>
 #include <string>
 #include <vector>

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) {
@@ -54,11 +51,23 @@ Message::ParseSignalsStatus Message::parseSignals(const std::vector<uint8_t>& da
 			case 64:
 				values.push_back((int64_t)v * signal.factor + signal.offset);
 				break;
-			default:
-				return ParseSignalsStatus::ErrorInvalidConversion;
+			default: {
+				// 2 complement -> decimal
+				const int negative = (v & (1 << (signal.size - 1))) != 0;
+				int64_t nativeInt;
+				if (negative)
+					nativeInt = v | ~((1 << signal.size) - 1); // invert all bits above signal.size
+				else
+					nativeInt = v & ((1 << signal.size) - 1); // masking
+				values.push_back(nativeInt * signal.factor + signal.offset);
+				break;
 			}
-		} else
+			}
+		} else {
+			// use only the relevant bits
+			v = v & ((1 << signal.size) - 1); // masking
 			values.push_back(v * signal.factor + signal.offset);
+		}
 	}
 	return ParseSignalsStatus::Success;
 }

test/test_dbc.cpp

@@ -80,6 +80,7 @@ TEST_CASE("Testing  big endian, little endian") {
 	parser.parse_file(filename);
 
 	REQUIRE(parser.get_messages().size() == 1);
+	REQUIRE(parser.get_messages().at(0).name() == "MSG1");
 	REQUIRE(parser.get_messages().at(0).getSignals().size() == 2);
 	{
 		const auto signal = parser.get_messages().at(0).getSignals().at(0);
@@ -104,6 +105,7 @@ TEST_CASE("Testing negative values") {
 	parser.parse_file(filename);
 
 	REQUIRE(parser.get_messages().size() == 1);
+	REQUIRE(parser.get_messages().at(0).name() == "MSG1");
 	REQUIRE(parser.get_messages().at(0).getSignals().size() == 4);
 
 	SECTION("Evaluating first message") {
@@ -146,6 +148,7 @@ TEST_CASE("Special characters in unit") {
 	parser.parse_file(filename);
 
 	REQUIRE(parser.get_messages().size() == 1);
+	REQUIRE(parser.get_messages().at(0).name() == "MSG1");
 	REQUIRE(parser.get_messages().at(0).getSignals().size() == 1);
 	SECTION("Checking that signal with special characters as unit is parsed correctly") {
 		const auto signal = parser.get_messages().at(0).getSignals().at(0);
@@ -165,6 +168,7 @@ VAL_ 234 State1 123 "Description 1" 0 "Description 2" 90903489 "Big value and sp
 	parser.parse_file(filename);
 
 	REQUIRE(parser.get_messages().size() == 1);
+	REQUIRE(parser.get_messages().at(0).name() == "MSG1");
 	REQUIRE(parser.get_messages().at(0).getSignals().size() == 2);
 
 	REQUIRE(parser.get_messages().at(0).getSignals().at(0).svDescriptions.size() == 3);
@@ -194,6 +198,7 @@ VAL_ 3221225472 State1 123 "Description 1" 0 "Description 2" 4000000000 "Big val
 	parser.parse_file(filename);
 
 	REQUIRE(parser.get_messages().size() == 1);
+	REQUIRE(parser.get_messages().at(0).name() == "MSG1");
 	REQUIRE(parser.get_messages().at(0).getSignals().size() == 2);
 
 	REQUIRE(parser.get_messages().at(0).getSignals().at(0).svDescriptions.size() == 3);
@@ -217,7 +222,7 @@ TEST_CASE("Signal Value Multiple VAL_") {
 	create_tmp_dbc_with(filename, R"(BO_ 3221225472 MSG1: 8 Vector__XXX
  SG_ State1 : 0|8@1+ (1,0) [0|200] "Km/h"  DEVICE1,DEVICE2,DEVICE3
  SG_ State2 : 0|8@1+ (1,0) [0|204] ""  DEVICE1,DEVICE2,DEVICE3"
-BO_ 123 MSG1: 8 Vector__XXX
+BO_ 123 MSG2: 8 Vector__XXX
  SG_ State1 : 0|8@1+ (1,0) [0|200] "Km/h"  DEVICE1,DEVICE2,DEVICE3
  SG_ State2 : 0|8@1+ (1,0) [0|204] ""  DEVICE1,DEVICE2,DEVICE3
 VAL_ 3221225472 State1 123 "Description 1" 0 "Description 2" ;
@@ -227,6 +232,9 @@ VAL_ 123 State1 123 "Description 3" 0 "Description 4" ;)");
 	parser.parse_file(filename);
 
 	REQUIRE(parser.get_messages().size() == 2);
+	REQUIRE(parser.get_messages().at(0).name() == "MSG1");
+	REQUIRE(parser.get_messages().at(1).name() == "MSG2");
+
 	REQUIRE(parser.get_messages().at(0).getSignals().size() == 2);
 
 	REQUIRE(parser.get_messages().at(0).getSignals().at(0).svDescriptions.size() == 2);

test/test_parseMessage.cpp

@@ -141,3 +141,41 @@ TEST_CASE("Parse Message big endian signed values") {
 	REQUIRE(Catch::Approx(result_values.at(10)) == 3.5050);
 	REQUIRE(Catch::Approx(result_values.at(11)) == 21.6);
 }
+
+TEST_CASE("Parse Message with non byte aligned values") {
+	const auto* filename = std::tmpnam(NULL);
+	create_tmp_dbc_with(filename, R"(BO_ 403 INFORMATION: 8 Vector__XXX
+ SG_ Voltage : 30|9@1+ (0.2,0) [0|102.2] "V"  Vector__XXX
+ SG_ Phase_Current : 20|10@1- (1,0) [-512|512] "A"  Vector__XXX
+ SG_ Iq_Current : 10|10@1- (1,0) [-512|512] "A"  Vector__XXX
+ SG_ Id_Current : 0|10@1- (1,0) [-512|512] "A"  Vector__XXX)");
+
+	libdbc::DbcParser p;
+	p.parse_file(filename);
+
+	std::vector<uint8_t> data{131, 51, 33, 9, 33, 0, 0, 0};
+	std::vector<double> result_values;
+	REQUIRE(p.parseMessage(403, data, result_values) == libdbc::Message::ParseSignalsStatus::Success);
+	REQUIRE(result_values.size() == 4);
+	REQUIRE(Catch::Approx(result_values.at(0)) == 26.4);
+	REQUIRE(Catch::Approx(result_values.at(1)) == 146);
+	REQUIRE(Catch::Approx(result_values.at(2)) == 76);
+	REQUIRE(Catch::Approx(result_values.at(3)) == -125);
+}
+
+TEST_CASE("Parse Message data length < 8 unsigned") {
+	const auto* filename = std::tmpnam(NULL);
+	create_tmp_dbc_with(filename, R"(BO_ 234 MSG1: 8 Vector__XXX
+ SG_ Msg1Sig1 : 7|8@0+ (1,0) [-3276.8|-3276.7] "C" Vector__XXX
+ SG_ Msg1Sig2 : 15|8@0+ (1,0) [-3276.8|-3276.7] "km/h" Vector__XXX)");
+
+	libdbc::DbcParser p;
+	p.parse_file(filename);
+
+	std::vector<uint8_t> data{0x1, 0x2};
+	std::vector<double> result_values;
+	REQUIRE(p.parseMessage(234, data, result_values) == libdbc::Message::ParseSignalsStatus::Success);
+	REQUIRE(result_values.size() == 2);
+	REQUIRE(Catch::Approx(result_values.at(0)) == 0x1);
+	REQUIRE(Catch::Approx(result_values.at(1)) == 0x2);
+}