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.

Bug-AGL: SPEC-2988

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

2 files changed, 31 insertions, 0 deletions

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..45233268 100644
--- a/low-can-binding/utils/converter.hpp
+++ b/low-can-binding/utils/converter.hpp
@@ -24,4 +24,5 @@ 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 uint32_t bit_position_swap(uint32_t bit_position,uint32_t bit_size);
 };