diff options
| -rw-r--r-- | README.mkd | 23 | ||||
| -rw-r--r-- | src/canutil/read.h | 8 | ||||
| -rw-r--r-- | tests/read_tests.c | 13 |
3 files changed, 43 insertions, 1 deletions
@@ -1,6 +1,29 @@ CAN Message Utilities for C ============ +## Bitfield Manipulation + +## CAN Signal Encoding + +## CAN Signal Decoding + +The library supports parsing floating point CAN signals as well as booleans. + + uint64_t payload = 0xeb00000000000000; + float result = bitfield_parse_float(payload, + 2, // starting bit + 4, // width of the signal's field + 1001.0, // transformation factor for the signal value + -30000.0); // transformation offset for the signal value + // result == -19990.0 + + bool result = bitfield_parse_bool(payload, + 0, // starting bit + 1, // width of the signal's field + 1.0, // transformation factor for the signal value + 0); // transformation offset for the signal value + // result == true + ## Testing The library includes a test suite that uses the `check` C unit test library. diff --git a/src/canutil/read.h b/src/canutil/read.h index 3742d6d1..028b03a6 100644 --- a/src/canutil/read.h +++ b/src/canutil/read.h @@ -19,6 +19,14 @@ extern "C" { float bitfield_parse_float(uint64_t data, uint8_t bit_offset, uint8_t bit_size, float factor, float offset); +/* Public: Parse a CAN signal from a message and interpret it as a boolean. + * + * signal - The details of the signal to decode and forward. + * data - The raw bytes of the CAN message that contains the signal, assumed + * to be in big-endian byte order from CAN. + * + * Returns false if the value was 0, otherwise true. + */ bool bitfield_parse_bool(uint64_t data, uint8_t bit_offset, uint8_t bit_size, float factor, float offset); diff --git a/tests/read_tests.c b/tests/read_tests.c index 62ced1f9..71b0ab65 100644 --- a/tests/read_tests.c +++ b/tests/read_tests.c @@ -6,18 +6,29 @@ const uint64_t BIG_ENDIAN_TEST_DATA = __builtin_bswap64(0xEB00000000000000); START_TEST (test_parse_float) { - float result = bitfield_parse_float(BIG_ENDIAN_TEST_DATA, 2, 4, 1001.0, -30000.0); + float result = bitfield_parse_float(BIG_ENDIAN_TEST_DATA, 2, 4, 1001.0, + -30000.0); float correctResult = 0xA * 1001.0 - 30000.0; fail_unless(result == correctResult, "parse is incorrect: %f but should be %f", result, correctResult); } END_TEST +START_TEST (test_parse_bool) +{ + float result = bitfield_parse_bool(BIG_ENDIAN_TEST_DATA, 0, 1, 1.0, 0); + float correctResult = true; + fail_unless(result == correctResult, + "parse is incorrect: %d but should be %d", result, correctResult); +} +END_TEST + Suite* canreadSuite(void) { Suite* s = suite_create("read"); TCase *tc_core = tcase_create("core"); tcase_add_checked_fixture(tc_core, NULL, NULL); tcase_add_test(tc_core, test_parse_float); + tcase_add_test(tc_core, test_parse_bool); suite_add_tcase(s, tc_core); return s; |