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authorRomain Forlot <romain.forlot@iot.bzh>2019-12-08 15:56:39 +0100
committerRomain Forlot <romain.forlot@iot.bzh>2020-01-09 16:25:36 +0100
commitfe780799e8117ac30f9c05bcd43616638f35e66a (patch)
treefdb8446af8e6b2d2198a3426c15368134870ebf8 /low-can-binding/utils
parent82fcc034ffcd4a4b6566ea96f87c76fbdb522d1e (diff)
converter: Improve bit_position computation
- Fix wrong bit_position swap computed: Need to multiply then lenght in bytes by 8 to get it for bits. - Add a continental bit_position function: This allow to get the correct bit_position using the weird Continental. bit numbering method where the Frame is read using little endianness and bit count using a big endianness - Use define CHAR_BIT instead of hardcoded 8 value Change-Id: I8d458ab457f80e5fa116af942acfceaaef51b763 Signed-off-by: Romain Forlot <romain.forlot@iot.bzh>
Diffstat (limited to 'low-can-binding/utils')
-rw-r--r--low-can-binding/utils/converter.cpp50
-rw-r--r--low-can-binding/utils/converter.hpp3
2 files changed, 23 insertions, 30 deletions
diff --git a/low-can-binding/utils/converter.cpp b/low-can-binding/utils/converter.cpp
index 6392fbdf..c6c2f5e1 100644
--- a/low-can-binding/utils/converter.cpp
+++ b/low-can-binding/utils/converter.cpp
@@ -19,6 +19,7 @@
#include <sstream>
#include <net/if.h>
#include <afb/afb-binding>
+#include <climits>
/**
* @brief Convert hex data to string
@@ -51,9 +52,9 @@ std::string converter_t::to_hex(const uint8_t data[], const size_t length)
void converter_t::signal_to_bits_bytes(unsigned int bit_position, unsigned int bit_size, int &new_start_byte, int &new_end_byte, uint8_t &new_start_bit, uint8_t &new_end_bit)
{
new_start_byte = bit_position >> 3;
- new_start_bit = bit_position % 8;
+ new_start_bit = bit_position % CHAR_BIT;
new_end_byte = (bit_position + bit_size - 1) >> 3;
- new_end_bit = (bit_position + bit_size - 1) % 8;
+ new_end_bit = (bit_position + bit_size - 1) % CHAR_BIT;
}
@@ -61,38 +62,27 @@ void converter_t::signal_to_bits_bytes(unsigned int bit_position, unsigned int b
* @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 msg_length Message length in bytes.
* @param bit_position Original bit position.
- * @param bit_size Size of the data.
+ * @param bit_size Size of the data.
* @return uint32_t New bit position.
*/
uint32_t converter_t::bit_position_swap(unsigned int msg_length, unsigned int bit_position, unsigned int bit_size)
{
- return msg_length - bit_position - bit_size;
- /*
- unsigned int start_byte_position = (unsigned int)(bit_position/8);
- unsigned int bit_size_rest = bit_size;
-
- if((int)(bit_size-(8 + start_byte_position * 8 - bit_position % 8)) > 0)
- {
- AFB_ERROR("Error: bit_position and bit_size getting out of range");
- return bit_position;
- }
+ return (msg_length * CHAR_BIT) - bit_position - bit_size;
+}
- if(bit_size <= 8 &&
- ((bit_position+bit_size) % 8 == bit_size ||
- (bit_position+bit_size)%8==0))
- {
- return (unsigned int)(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 (unsigned int)(start_byte_position*8 + (8-bit_size_rest));
- }
- */
+/**
+ * @brief This allow to get the correct bit_position using the weird Continental.
+ * bit numbering method where the Frame is read using little endianness
+ * and bit count using a big endianness
+ *
+ * @param msg_length Message length in bytes.
+ * @param bit_position Original bit position.
+ * @param bit_size Size of the data.
+ * @return uint32_t New bit position.
+ */
+uint32_t converter_t::continental_bit_position_mess(unsigned int msg_length, unsigned int bit_position, unsigned int bit_size)
+{
+ return bit_position + (CHAR_BIT - bit_position % CHAR_BIT) - bit_size;
}
diff --git a/low-can-binding/utils/converter.hpp b/low-can-binding/utils/converter.hpp
index 23f8ae77..45e29e9a 100644
--- a/low-can-binding/utils/converter.hpp
+++ b/low-can-binding/utils/converter.hpp
@@ -32,4 +32,7 @@ class converter_t
static uint32_t bit_position_swap(unsigned int msg_length,
unsigned int bit_position,
unsigned int bit_size);
+ static uint32_t continental_bit_position_mess(unsigned int msg_length,
+ unsigned int bit_position,
+ unsigned int bit_size);
};