can: Add big endian CAN frame layout handle

- can-decoder.cpp: translate_signal() : Tests "frame_layout_is_little".
If false the signal's bit position is changed to fit the layout.

- message-definition.cpp: Added the new attribute
"frame_layout_is_little" and its getter.

- signals.cpp: Added a setter to the bit_position attribute.

- converter.cpp: Added a methode to convert a big endian bit_position
to a right (little endian) bit_position.

Change-Id: I004c9069eb00f389564927cd12d1b30470c3a59d
Signed-off-by: Corentin Le Gall <corentin.legall@iot.bzh>

7 files changed, 56 insertions, 3 deletions

diff --git a/low-can-binding/can/can-decoder.cpp b/low-can-binding/can/can-decoder.cpp
index e901240b..a6b6c14d 100644
--- a/low-can-binding/can/can-decoder.cpp
+++ b/low-can-binding/can/can-decoder.cpp
@@ -294,7 +294,10 @@ 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,
diff --git a/low-can-binding/can/message-definition.cpp b/low-can-binding/can/message-definition.cpp
index 114307e5..80609827 100644
--- a/low-can-binding/can/message-definition.cpp
+++ b/low-can-binding/can/message-definition.cpp
@@ -23,6 +23,7 @@ message_definition_t::message_definition_t(
 	const std::string bus,
 	uint32_t id,
 	uint32_t flags,
+	bool frame_layout_is_little,
 	frequency_clock_t frequency_clock,
 	bool force_send_changed,
 	const vect_ptr_signal_t& signals)
@@ -30,6 +31,7 @@ message_definition_t::message_definition_t(
 	bus_{bus},
 	id_{id},
 	flags_{flags},
+	frame_layout_is_little_{frame_layout_is_little},
 	frequency_clock_{frequency_clock},
 	force_send_changed_{force_send_changed},
 	last_value_{CAN_MESSAGE_SIZE},
@@ -41,6 +43,7 @@ message_definition_t::message_definition_t(const std::string bus,
 	const std::string name,
 	uint32_t length,
 	uint32_t flags,
+	bool frame_layout_is_little,
 	frequency_clock_t frequency_clock,
 	bool force_send_changed,
 	const vect_ptr_signal_t& signals)
@@ -50,6 +53,7 @@ message_definition_t::message_definition_t(const std::string bus,
 	name_{name},
 	length_{length},
 	flags_{flags},
+	frame_layout_is_little_{frame_layout_is_little},
 	frequency_clock_{frequency_clock},
 	force_send_changed_{force_send_changed},
 	last_value_{CAN_MESSAGE_SIZE},
@@ -112,3 +116,7 @@ uint32_t message_definition_t::get_flags() const
 {
 	return flags_;
 }
+
+bool message_definition_t::frame_layout_is_little() const{
+	return frame_layout_is_little_;
+}
diff --git a/low-can-binding/can/message-definition.hpp b/low-can-binding/can/message-definition.hpp
index ca264b7e..9d615ff0 100644
--- a/low-can-binding/can/message-definition.hpp
+++ b/low-can-binding/can/message-definition.hpp
@@ -49,6 +49,8 @@ private:
 	frequency_clock_t frequency_clock_; ///<  clock_ - an optional frequency clock to control the output of this
 							///      message, if sent raw, or simply to mark the max frequency for custom
 							///      handlers to retrieve.*/
+	bool frame_layout_is_little_; ///<frame_layout_is_little_ Defines if the can frame layout is little endian or big endian.
+								  /// Default is true;
 	bool force_send_changed_; ///< force_send_changed_ - If true, regardless of the frequency, it will send CAN
 							///	message if it has changed when using raw passthrough.*/
 	std::vector<uint8_t> last_value_; ///< last_value_ - The last received value of the message. Defaults to undefined.
@@ -64,6 +66,7 @@ public:
 	message_definition_t(const std::string bus,
 				 uint32_t id,
 				 uint32_t flags,
+				 bool frame_layout_is_little,
 				 frequency_clock_t frequency_clock,
 				 bool force_send_changed,
 				 const vect_ptr_signal_t& signals);
@@ -72,6 +75,7 @@ public:
 				 std::string name,
 				 uint32_t length,
 				 uint32_t flags,
+				 bool frame_layout_is_little,
 				 frequency_clock_t frequency_clock,
 				 bool force_send_changed,
 				 const vect_ptr_signal_t& signals);
@@ -87,6 +91,7 @@ public:
 	vect_ptr_signal_t& get_signals();
 	uint32_t get_length() const;
 	uint32_t get_flags() const;
+	bool frame_layout_is_little() const;
 
 	void set_parent(std::shared_ptr<message_set_t> parent);
 	void set_last_value(std::shared_ptr<message_t>  m);
diff --git a/low-can-binding/can/signals.cpp b/low-can-binding/can/signals.cpp
index 57aefa55..2b87dc6f 100755
--- a/low-can-binding/can/signals.cpp
+++ b/low-can-binding/can/signals.cpp
@@ -220,7 +220,12 @@ void signal_t::set_timestamp(uint64_t timestamp)
 	frequency_.tick(timestamp);
 }
 
-std::pair<bool, int> signal_t::get_multiplex() const
+void signal_t::set_bit_position(uint32_t bit_position)
+{
+	bit_position_=bit_position;
+}
+
+std::pair<bool,int> signal_t::get_multiplex() const
 {
 	return multiplex_;
 }
diff --git a/low-can-binding/can/signals.hpp b/low-can-binding/can/signals.hpp
index 32cd7606..d9453c50 100755
--- a/low-can-binding/can/signals.hpp
+++ b/low-can-binding/can/signals.hpp
@@ -171,4 +171,5 @@ public:
 	void set_received(bool r);
 	void set_last_value(float val);
 	void set_timestamp(uint64_t timestamp);
+	void set_bit_position(uint32_t bit_position);
 };
diff --git a/low-can-binding/utils/converter.cpp b/low-can-binding/utils/converter.cpp
index e3db7f33..f790fc00 100644
--- a/low-can-binding/utils/converter.cpp
+++ b/low-can-binding/utils/converter.cpp
@@ -55,3 +55,33 @@ void converter_t::signal_to_bits_bytes(uint32_t bit_position, uint32_t bit_size,
 	new_end_byte = (bit_position + bit_size - 1) >> 3;
 	new_end_bit = (bit_position + bit_size - 1) % 8;
 }
+
+
+/**
+ * @brief 	This is to use when you have a big endian CAN frame layout.
+ * 		  	It converts the bit position so it matches with little endiant CAN frame layout.
+ *
+ * @param bit_position 	Original bit position.
+ * @param bit_size 		Size of the data.
+ * @return uint32_t 	New little endian bit position.
+ */
+uint32_t converter_t::bit_position_swap(uint32_t bit_position,uint32_t bit_size)
+{
+	uint32_t start_byte_position = (uint32_t)(bit_position/8);
+	uint32_t bit_size_rest = bit_size;
+	if(bit_size<=8 && ((bit_position+bit_size)%8==bit_size || (bit_position+bit_size)%8==0))
+	{
+		return (uint32_t)(start_byte_position*8 + (8-bit_size));
+	}
+	else
+	{
+		do
+		{
+			bit_size_rest = bit_size_rest - ((start_byte_position+1)*8-bit_position);
+			start_byte_position--;
+			bit_position = start_byte_position*8;
+		} while (bit_size_rest>8);
+		return (uint32_t)(start_byte_position*8 + (8-bit_size_rest));
+	}
+
+}
diff --git a/low-can-binding/utils/converter.hpp b/low-can-binding/utils/converter.hpp
index d24096a6..cb52f1ac 100644
--- a/low-can-binding/utils/converter.hpp
+++ b/low-can-binding/utils/converter.hpp
@@ -23,5 +23,6 @@ class converter_t
 {
 	public:
 		static std::string to_hex(const uint8_t data[], const size_t length);
-		static void signal_to_bits_bytes(uint32_t bit_position, uint32_t bit_size, int &new_start_byte, int &new_end_byte, uint8_t &new_start_bit, uint8_t &new_end_bit);
+		static void signal_to_bits_bytes(uint32_t bit_position, uint32_t bit_size, int &new_start_byte, int &new_end_byte, int &new_start_bit, int &new_end_bit);
+		static uint32_t bit_position_swap(uint32_t bit_position,uint32_t bit_size);
 };