diff options
Diffstat (limited to 'libs/bitfield-c/src/canutil')
| -rw-r--r-- | libs/bitfield-c/src/canutil/read.c | 34 | ||||
| -rw-r--r-- | libs/bitfield-c/src/canutil/read.h | 81 | ||||
| -rw-r--r-- | libs/bitfield-c/src/canutil/write.c | 48 | ||||
| -rw-r--r-- | libs/bitfield-c/src/canutil/write.h | 57 |
4 files changed, 220 insertions, 0 deletions
diff --git a/libs/bitfield-c/src/canutil/read.c b/libs/bitfield-c/src/canutil/read.c new file mode 100644 index 00000000..d0cbb71a --- /dev/null +++ b/libs/bitfield-c/src/canutil/read.c @@ -0,0 +1,34 @@ +#include <canutil/read.h> +#include <bitfield/bitfield.h> +#include <bitfield/8byte.h> + +static float decode_float(uint64_t raw, float factor, float offset) { + return raw * factor + offset; +} + +float eightbyte_parse_float(uint64_t data, uint8_t bit_offset, uint8_t bit_size, + float factor, float offset) { + return decode_float(eightbyte_get_bitfield(data, bit_offset, bit_size, + true), factor, offset); +} + +bool eightbyte_parse_bool(uint64_t data, uint8_t bit_offset, uint8_t bit_size, + float factor, float offset) { + float value = eightbyte_parse_float(data, bit_offset, bit_size, factor, offset); + return value == 0.0 ? false : true; +} + +float bitfield_parse_float(const uint8_t source[], const uint16_t source_length, + const uint8_t bit_offset, const uint8_t bit_size, const float factor, + const float offset) { + return decode_float(get_bitfield(source, source_length, bit_offset, bit_size), + factor, offset); +} + +bool bitfield_parse_bool(const uint8_t source[], const uint16_t source_length, + const uint8_t bit_offset, const uint8_t bit_size, const float factor, + const float offset) { + float value = bitfield_parse_float(source, source_length, bit_offset, + bit_size, factor, offset); + return value == 0.0 ? false : true; +} diff --git a/libs/bitfield-c/src/canutil/read.h b/libs/bitfield-c/src/canutil/read.h new file mode 100644 index 00000000..86fea785 --- /dev/null +++ b/libs/bitfield-c/src/canutil/read.h @@ -0,0 +1,81 @@ +#ifndef __READ_H__ +#define __READ_H__ + +#include <stdint.h> +#include <stdbool.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/* Public: Parse a CAN signal from a message and apply required transformation. + * + * source - the payload containing the signal. + * bit_offset - the starting bit for the signal. + * bit_size - the width of the signal. + * factor - the transformation factor for the signal value, applied after + * pulling out the bit field. Use 1.0 for no factor. + * offset - the transformation offset for the signal value, applied after + * pulling out the bit field. Use 0 for no offset. + * + * Returns the decoded and transformed value of the signal. + */ +float eightbyte_parse_float(const uint64_t source, const uint8_t bit_offset, + const uint8_t bit_size, const float factor, const float offset); + +/* Public: Parse a CAN signal from a message storage as a byte array and apply + * required transformation. + * + * source - the payload containing the signal. + * source_size - the size of the payload in bytes. + * bit_offset - the starting bit for the signal. + * bit_size - the width of the signal. + * factor - the transformation factor for the signal value, applied after + * pulling out the bit field. Use 1.0 for no factor. + * offset - the transformation offset for the signal value, applied after + * pulling out the bit field. Use 0 for no offset. + * + * Returns the decoded and transformed value of the signal. + */ +float bitfield_parse_float(const uint8_t source[], const uint16_t source_size, + const uint8_t bit_offset, const uint8_t bit_size, const float factor, + const float offset); + +/* Public: Parse a CAN signal from a message and interpret it as a boolean. + * + * source - the payload containing the signal. + * bit_offset - the starting bit for the signal. + * bit_size - the width of the signal. + * factor - the transformation factor for the signal value, applied after + * pulling out the bit field. Use 1.0 for no factor. + * offset - the transformation offset for the signal value, applied after + * pulling out the bit field. Use 0 for no offset. + * + * Returns false if the value was 0, otherwise true. + */ +bool eightbyte_parse_bool(uint64_t source, uint8_t bit_offset, uint8_t bit_size, + float factor, float offset); + +/* Public: Parse a CAN signal from a message storage as a byte array and + * interpret it as a boolean. + * + * source - the payload containing the signal. + * source_size - the size of the payload in bytes. + * bit_offset - the starting bit for the signal. + * bit_size - the width of the signal. + * factor - the transformation factor for the signal value, applied after + * pulling out the bit field. Use 1.0 for no factor. + * offset - the transformation offset for the signal value, applied after + * pulling out the bit field. Use 0 for no offset. + * + * Returns false if the value was 0, otherwise true. + */ +bool bitfield_parse_bool(const uint8_t source[], const uint16_t source_size, + const uint8_t bit_offset, const uint8_t bit_size, const float factor, + const float offset); + +#ifdef __cplusplus +} +#endif + +#endif // __READ_H__ diff --git a/libs/bitfield-c/src/canutil/write.c b/libs/bitfield-c/src/canutil/write.c new file mode 100644 index 00000000..7f3a3e04 --- /dev/null +++ b/libs/bitfield-c/src/canutil/write.c @@ -0,0 +1,48 @@ +#include <canutil/write.h> +#include <bitfield/bitfield.h> +#include <bitfield/8byte.h> + +uint64_t float_to_fixed_point(const float value, const float factor, + const float offset) { + float raw = (value - offset) / factor; + if(raw > 0) { + // round up to avoid losing precision when we cast to an int + // TODO do we need a way to encode an int back to a signal without any + // rounding? + raw += 0.5; + } + return (uint64_t)raw; +} + +uint64_t eightbyte_encode_float(float value, uint8_t bit_offset, uint8_t bit_size, + float factor, float offset) { + uint64_t result = 0; + if(!eightbyte_set_bitfield(float_to_fixed_point(value, factor, offset), + bit_offset, bit_size, &result)) { + // debug("%f will not fit in a %d bit field", value, bit_size); + } + return result; +} + +uint64_t eightbyte_encode_bool(const bool value, const uint8_t bit_offset, + const uint8_t bit_size) { + return eightbyte_encode_float(value, bit_offset, bit_size, 1.0, 0); +} + +bool bitfield_encode_float(const float value, const uint8_t bit_offset, + const uint8_t bit_size, const float factor, const float offset, + uint8_t destination[], const uint8_t destination_length) { + if(!set_bitfield(float_to_fixed_point(value, factor, offset), bit_offset, + bit_size, destination, destination_length)) { + // debug("%f will not fit in a %d bit field", value, bit_size); + return false; + } + return true; +} + +bool bitfield_encode_bool(const bool value, const uint8_t bit_offset, + const uint8_t bit_size, uint8_t destination[], + const uint16_t destination_length) { + return bitfield_encode_float(value, bit_offset, bit_size, 1.0, 0, + destination, destination_length); +} diff --git a/libs/bitfield-c/src/canutil/write.h b/libs/bitfield-c/src/canutil/write.h new file mode 100644 index 00000000..c2bef20e --- /dev/null +++ b/libs/bitfield-c/src/canutil/write.h @@ -0,0 +1,57 @@ +#ifndef __WRITE_H__ +#define __WRITE_H__ + +#include <stdint.h> +#include <stdbool.h> + +#ifdef __cplusplus +extern "C" { +#endif + +/* Public: Encode a floating point number into a fixed point, fixed bit width + * field in a bit array. + * + * value - the floating point value to encode. + * bit_offset - the starting point for the encoded bits in the returned value. + * bit_size - The max width of the field in the resulting bit array. If bit_size + * isn't big enough to store the fixed point version of the value, the + * bitfeld will *not* be set. TODO some error reporting would be nice. + * factor - a factor used to transform from floating to fixed point before + * encoding. Use 1.0 for no factor. + * offset - an offset used to transform from floating to fixed point before + * encoding. Use 0 for no offset. + * + * Returns a big-endian uint64_t with the value encoded as a bitfield. + */ +uint64_t eightbyte_encode_float(float value, uint8_t bit_offset, + uint8_t bit_size, float factor, float offset); + +uint64_t float_to_fixed_point(const float value, const float factor, + const float offset); + +bool bitfield_encode_float(const float value, const uint8_t bit_offset, + const uint8_t bit_size, const float factor, const float offset, + uint8_t destination[], const uint8_t destination_length); + +/* Public: Encode a boolean into fixed bit width field in a bit array. + * + * value - the boolean value to encode - true will be 1, false will be 0. + * bit_offset - the starting point for the encoded bits in the returned value. + * bit_size - The max width of the field in the resulting bit array. If bit_size + * isn't big enough to store the fixed point version of the value, the + * bitfeld will *not* be set. TODO some error reporting would be nice. + * + * Returns a big-endian uint64_t with the value encoded as a bitfield. + */ +uint64_t eightbyte_encode_bool(const bool value, const uint8_t bit_offset, + const uint8_t bit_size); + +bool bitfield_encode_bool(const bool value, const uint8_t bit_offset, const + uint8_t bit_size, uint8_t destination[], + const uint16_t destination_length); + +#ifdef __cplusplus +} +#endif + +#endif // __WRITE_H__ |