diff options
| -rw-r--r-- | src/bitfield/8byte.c | 11 | ||||
| -rw-r--r-- | src/bitfield/8byte.h | 5 | ||||
| -rw-r--r-- | tests/8byte_tests.c | 24 |
3 files changed, 26 insertions, 14 deletions
diff --git a/src/bitfield/8byte.c b/src/bitfield/8byte.c index 77251996..3b6b5466 100644 --- a/src/bitfield/8byte.c +++ b/src/bitfield/8byte.c @@ -40,16 +40,17 @@ uint64_t get_bit_field(uint64_t source, const uint16_t startBit, return int_result; } -/** - * TODO it would be nice to have a warning if you call with this a value that - * won't fit in the number of bits you've specified it should use. - */ -void set_bit_field(uint64_t* destination, uint64_t value, const uint16_t offset, +bool set_bit_field(uint64_t* destination, uint64_t value, const uint16_t offset, const uint16_t bit_count) { + if(value > bitmask(bit_count)) { + return false; + } + int shiftDistance = EIGHTBYTE_BIT - offset - bit_count; value <<= shiftDistance; *destination &= ~(bitmask(bit_count) << shiftDistance); *destination |= value; + return true; } uint8_t nth_byte(const uint64_t source, const uint16_t byte_index) { diff --git a/src/bitfield/8byte.h b/src/bitfield/8byte.h index 9cbf61a9..36b5fe60 100644 --- a/src/bitfield/8byte.h +++ b/src/bitfield/8byte.h @@ -55,8 +55,11 @@ uint64_t get_bit_field(uint64_t source, const uint16_t offset, * value - the value to set in the bit field. * offset - the starting index of the bit field (beginning from 0). * bit_count - the number of bits to set in the data. + * + * Returns true if the bit_count is enough to fully represent the value, and + * false if it will not fit. */ -void set_bit_field(uint64_t* destination, uint64_t value, const uint16_t offset, +bool set_bit_field(uint64_t* destination, uint64_t value, const uint16_t offset, const uint16_t bit_count); /* Public: Retreive the nth byte out of 8 bytes in a uint64_t. diff --git a/tests/8byte_tests.c b/tests/8byte_tests.c index f4188bfe..64c1a399 100644 --- a/tests/8byte_tests.c +++ b/tests/8byte_tests.c @@ -103,19 +103,26 @@ START_TEST (test_get_off_byte_boundary) ck_assert_int_eq(result, 0x01); } END_TEST +START_TEST (test_set_wont_fit) +{ + uint64_t data = 0; + fail_if(set_bit_field(&data, 100, 0, 1)); +} +END_TEST + START_TEST (test_set_field) { uint64_t data = 0; - set_bit_field(&data, 1, 0, 1); + fail_unless(set_bit_field(&data, 1, 0, 1)); uint64_t result = get_bit_field(data, 0, 1, false); ck_assert_int_eq(result, 0x1); data = 0; - set_bit_field(&data, 1, 1, 1); + fail_unless(set_bit_field(&data, 1, 1, 1)); result = get_bit_field(data, 1, 1, false); ck_assert_int_eq(result, 0x1); data = 0; - set_bit_field(&data, 0xf, 3, 4); + fail_unless(set_bit_field(&data, 0xf, 3, 4)); result = get_bit_field(data, 3, 4, false); ck_assert_int_eq(result, 0xf); } @@ -124,14 +131,14 @@ END_TEST START_TEST (test_set_doesnt_clobber_existing_data) { uint64_t data = 0xFFFC4DF300000000; - set_bit_field(&data, 0x4fc8, 16, 16); + fail_unless(set_bit_field(&data, 0x4fc8, 16, 16)); uint64_t result = get_bit_field(data, 16, 16, false); fail_unless(result == 0x4fc8, "Field retrieved in 0x%llx was 0x%llx instead of 0x%x", data, result, 0xc84f); data = 0x8000000000000000; - set_bit_field(&data, 1, 21, 1); + fail_unless(set_bit_field(&data, 1, 21, 1)); fail_unless(data == 0x8000040000000000LLU, "Expected combined value 0x8000040000000000 but got 0x%llx%llx", data >> 32, data); @@ -141,7 +148,7 @@ END_TEST START_TEST (test_set_off_byte_boundary) { uint64_t data = 0xFFFC4DF300000000; - set_bit_field(&data, 0x12, 12, 8); + fail_unless(set_bit_field(&data, 0x12, 12, 8)); uint64_t result = get_bit_field(data, 12, 12, false); ck_assert_int_eq(result,0x12d); } @@ -150,14 +157,14 @@ END_TEST START_TEST (test_set_odd_number_of_bits) { uint64_t data = 0xFFFC4DF300000000LLU; - set_bit_field(&data, 0x12, 11, 5); + fail_unless(set_bit_field(&data, 0x12, 11, 5)); uint64_t result = get_bit_field(data, 11, 5, false); fail_unless(result == 0x12, "Field set in 0x%llx%llx%llx%llx was 0x%llx instead of 0x%llx", data, result, 0x12); data = 0xFFFC4DF300000000LLU; - set_bit_field(&data, 0x2, 11, 5); + fail_unless(set_bit_field(&data, 0x2, 11, 5)); result = get_bit_field(data, 11, 5, false); fail_unless(result == 0x2, "Field set in 0x%llx%llx%llx%llx was 0x%llx instead of 0x%llx", data, result, @@ -202,6 +209,7 @@ Suite* bitfieldSuite(void) { tcase_add_test(tc_core, test_multi_byte); tcase_add_test(tc_core, test_get_multi_byte); tcase_add_test(tc_core, test_get_off_byte_boundary); + tcase_add_test(tc_core, test_set_wont_fit); tcase_add_test(tc_core, test_set_field); tcase_add_test(tc_core, test_set_doesnt_clobber_existing_data); tcase_add_test(tc_core, test_set_off_byte_boundary); |