decoder: rework how to swap frame layout.

This also change the bit_position to retrieve the bit word starting from the left
or the right of the frame depending on the endianness of the frame layout.

Change-Id: I28658e9d46bd35d8ecabeece317331832229384a
Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>

2 files changed, 13 insertions, 1 deletions

diff --git a/low-can-binding/can/message/message.cpp b/low-can-binding/can/message/message.cpp
index 22887c9a..56e9379f 100644
--- a/low-can-binding/can/message/message.cpp
+++ b/low-can-binding/can/message/message.cpp
@@ -177,3 +177,14 @@ void message_t::set_length(uint32_t length)
 {
 	length_ = length;
 }
+
+void message_t::frame_swap()
+{
+	int i;
+	uint8_t *temp = (uint8_t*)alloca(length_);
+
+	for(i = 0; i < length_; i++)
+		temp[i] = data_[length_ - i - 1];
+
+	memcpy(data_.data(), temp, length_);
+}
diff --git a/low-can-binding/can/message/message.hpp b/low-can-binding/can/message/message.hpp
index 9a074e31..e5e6769b 100644
--- a/low-can-binding/can/message/message.hpp
+++ b/low-can-binding/can/message/message.hpp
@@ -44,7 +44,7 @@
 #define ISOTP_SEND 0x0020
 #define ISOTP_RECEIVE 0x0040
 #define CAN_PROTOCOL_WITH_FD_FRAME 0x0080
-#define FRAME_LAYOUT_IS_LE 0x0100
+#define FRAME_LAYOUT_IS_LE 0x0100 // LE stand for Little Endian
 
 /// @class message_t
 ///
@@ -84,4 +84,5 @@ public:
 	uint32_t get_maxdlen();
 	void set_maxdlen(uint32_t maxdlen);
 	void set_length(uint32_t length);
+	void frame_swap();
 };