diff options
Diffstat (limited to 'CAN-binder/libs/bitfield-c/src/bitfield/8byte.h')
-rw-r--r-- | CAN-binder/libs/bitfield-c/src/bitfield/8byte.h | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/CAN-binder/libs/bitfield-c/src/bitfield/8byte.h b/CAN-binder/libs/bitfield-c/src/bitfield/8byte.h new file mode 100644 index 0000000..0451269 --- /dev/null +++ b/CAN-binder/libs/bitfield-c/src/bitfield/8byte.h @@ -0,0 +1,88 @@ +#ifndef __8BYTE_H__ +#define __8BYTE_H__ + +#include <stdint.h> +#include <stdbool.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/* Public: Reads a subset of bits into a uint64_t. + * + * source - the bytes in question. + * offset - the starting index of the bit field (beginning from 0). + * bit_count - the width of the bit field to extract. + * data_is_big_endian - if the data passed in is little endian, set this to false and it + * will be flipped before grabbing the bit field. + * + * Bit fields are positioned according to big-endian bit layout. + * + * For example, the bit layout of the value "42" (i.e. 00101010 set at position + * 14 with length 6 is: + * + * 000000000000001010100000000000000000000000000000000000000000000 + * + * and the same value and position but with length 8 is: + * + * 000000000000000010101000000000000000000000000000000000000000000 + * + * If the architecture where is code is running is little-endian, the input data + * will be swapped before grabbing the bit field. + * + * Examples + * + * uint64_t value = get_bitfield(data, 2, 4); + * + * Returns the value of the requested bit field, right aligned in a uint64_t. + */ +uint64_t eightbyte_get_bitfield(uint64_t source, const uint16_t offset, + const uint16_t bit_count, const bool data_is_big_endian); + +/* Public: Return a single nibble from the payload, with range checking. + * + * source - the source payload. + * nibble_index - the index of the nibble to retreive. The leftmost nibble is + * index 0. + * data_is_big_endian - if the data passed in is little endian, set this to false and it + * will be flipped before grabbing the bit field. + * + * Returns the retreived nibble, right aligned in a uint8_t. + */ +uint8_t eightbyte_get_nibble(const uint64_t source, const uint8_t nibble_index, + const bool data_is_big_endian); + +/* Public: Return a single byte from the payload, with range checking. + * + * source - the source byte array. + * byte_index - the index of the byte to retreive. The leftmost byte is index 0. + * data_is_big_endian - if the data passed in is little endian, set this to false and it + * will be flipped before grabbing the bit field. + * + * Returns the retreived byte. + */ +uint8_t eightbyte_get_byte(const uint64_t source, const uint8_t byte_index, + const bool data_is_big_endian); + +/* Public: Set the bit field in the given data array to the new value. + * + * destination - a byte array with size at least offset + bit_count. + * 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. + */ +bool eightbyte_set_bitfield(uint64_t value, + const uint16_t offset, const uint16_t bit_count, uint64_t* destination); + +/* Private: Determine the index of the last bit used. + */ +uint8_t find_end_bit(const uint16_t num_bits); + +#ifdef __cplusplus +} +#endif + +#endif // __8BYTE_H__ |