sign: handle decode methods sign from can value

- add enumeration that represents the way of encoding:
    enum sign_t
    {
		UNSIGNED = 0,
		SIGN_BIT = 1,
		ONES_COMPLEMENT = 2,
		TWOS_COMPLEMENT = 3,
		SIGN_BIT_EXTERN = 4
    };

- the function handle_sign allows to transform value if negative and
return the sign of the value in order to be multiplied at the end ot the
parcing

Bug-AGL: SPEC-3021

Change-Id: I5766a286488170d930422474b4c4f3a8578ca726
Signed-off-by: Clément Bénier <clement.benier@iot.bzh>
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

1 files changed, 1 insertions, 0 deletions

diff --git a/low-can-binding/can/can-decoder.hpp b/low-can-binding/can/can-decoder.hpp
index a5e3acbe..02a2c7e1 100644
--- a/low-can-binding/can/can-decoder.hpp
+++ b/low-can-binding/can/can-decoder.hpp
@@ -24,6 +24,7 @@
 class decoder_t
 {
 public:
+	static int handle_sign(const signal_t& signal, std::vector<uint8_t>& data_signal, uint8_t new_end_bit, const std::vector<uint8_t>& can_data);
 	static float parse_signal_bitfield(signal_t& signal, std::shared_ptr<message_t> message);
 
 	static openxc_DynamicField decode_state(signal_t& signal, std::shared_ptr<message_t> message, bool* send);