can: Add big endian CAN frame layout handle

[apps/agl-service-can-low-level.git] / low-can-binding / utils / converter.cpp

diff --git a/low-can-binding/utils/converter.cpp b/low-can-binding/utils/converter.cpp
index e3db7f3..f790fc0 100644 (file)
--- 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));
+       }
+
+}