mirror of https://github.com/merbanan/rtl_433.git
229 lines
8.8 KiB
C
229 lines
8.8 KiB
C
/** @file
|
|
Various utility functions for use by device drivers.
|
|
|
|
Copyright (C) 2015 Tommy Vestermark
|
|
|
|
This program is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 2 of the License, or
|
|
(at your option) any later version.
|
|
*/
|
|
|
|
#ifndef INCLUDE_BIT_UTIL_H_
|
|
#define INCLUDE_BIT_UTIL_H_
|
|
|
|
#include <stdint.h>
|
|
|
|
/// Reverse (reflect) the bits in an 32 bit byte.
|
|
///
|
|
/// @param x input byte
|
|
/// @return bit reversed byte
|
|
uint32_t reverse32(uint32_t x);
|
|
|
|
|
|
/// Reverse (reflect) the bits in an 8 bit byte.
|
|
///
|
|
/// @param x input byte
|
|
/// @return bit reversed byte
|
|
uint8_t reverse8(uint8_t x);
|
|
|
|
/// Reflect (reverse LSB to MSB) each byte of a number of bytes.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param num_bytes number of bytes to reflect
|
|
void reflect_bytes(uint8_t message[], unsigned num_bytes);
|
|
|
|
/// Reflect (reverse LSB to MSB) each nibble in an 8 bit byte, preserves nibble order.
|
|
///
|
|
/// @param x input byte
|
|
/// @return reflected nibbles
|
|
uint8_t reflect4(uint8_t x);
|
|
|
|
/// Reflect (reverse LSB to MSB) each nibble in a number of bytes.
|
|
///
|
|
/// @param message bytes of nibble message data
|
|
/// @param num_bytes number of bytes to reflect
|
|
void reflect_nibbles(uint8_t message[], unsigned num_bytes);
|
|
|
|
/// Unstuff nibbles with 1-bit separator (4B1S) to bytes, returns number of successfully unstuffed nibbles.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param offset_bits start offset of message in bits
|
|
/// @param num_bits message length in bits
|
|
/// @param dst target buffer for extracted nibbles, at least num_bits/5 size
|
|
/// @return number of successfully unstuffed nibbles.
|
|
unsigned extract_nibbles_4b1s(uint8_t const *message, unsigned offset_bits, unsigned num_bits, uint8_t *dst);
|
|
|
|
/// UART "8n1" (10-to-8) decoder with 1 start bit (0), no parity, 1 stop bit (1), LSB-first bit-order.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param offset_bits start offset of message in bits
|
|
/// @param num_bits message length in bits
|
|
/// @param dst target buffer for extracted bytes, at least num_bits/10 size
|
|
/// @return number of successful decoded bytes
|
|
unsigned extract_bytes_uart(uint8_t const *message, unsigned offset_bits, unsigned num_bits, uint8_t *dst);
|
|
|
|
/// UART "8o1" (11-to-8) decoder with 1 start bit (1), odd parity, 1 stop bit (0), MSB-first bit-order.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param offset_bits start offset of message in bits
|
|
/// @param num_bits message length in bits
|
|
/// @param dst target buffer for extracted bytes, at least num_bits/11 size
|
|
/// @return number of successful decoded bytes
|
|
unsigned extract_bytes_uart_parity(uint8_t const *message, unsigned offset_bits, unsigned num_bits, uint8_t *dst);
|
|
|
|
/// Decode symbols to bits.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param offset_bits start offset of message in bits
|
|
/// @param num_bits message length in bits
|
|
/// @param zero symbol for zero bit, bits MSB aligned, count in LSB
|
|
/// @param one symbol for one bit, bits MSB aligned, count in LSB
|
|
/// @param sync symbol for sync bit, ignored at start, terminates at end
|
|
/// @param dst target buffer for extracted bits, at least num_bits/symbol_x_len size
|
|
/// @return number of successful decoded bits
|
|
unsigned extract_bits_symbols(uint8_t const *message, unsigned offset_bits, unsigned num_bits, uint32_t zero, uint32_t one, uint32_t sync, uint8_t *dst);
|
|
|
|
/// CRC-4.
|
|
///
|
|
/// @param message array of bytes to check
|
|
/// @param nBytes number of bytes in message
|
|
/// @param polynomial CRC polynomial
|
|
/// @param init starting crc value
|
|
/// @return CRC value
|
|
uint8_t crc4(uint8_t const message[], unsigned nBytes, uint8_t polynomial, uint8_t init);
|
|
|
|
/// CRC-7.
|
|
///
|
|
/// @param message array of bytes to check
|
|
/// @param nBytes number of bytes in message
|
|
/// @param polynomial CRC polynomial
|
|
/// @param init starting crc value
|
|
/// @return CRC value
|
|
uint8_t crc7(uint8_t const message[], unsigned nBytes, uint8_t polynomial, uint8_t init);
|
|
|
|
/// Generic Cyclic Redundancy Check CRC-8.
|
|
///
|
|
/// Example polynomial: 0x31 = x8 + x5 + x4 + 1 (x8 is implicit)
|
|
/// Example polynomial: 0x80 = x8 + x7 (a normal bit-by-bit parity XOR)
|
|
///
|
|
/// @param message array of bytes to check
|
|
/// @param nBytes number of bytes in message
|
|
/// @param polynomial byte is from x^7 to x^0 (x^8 is implicitly one)
|
|
/// @param init starting crc value
|
|
/// @return CRC value
|
|
uint8_t crc8(uint8_t const message[], unsigned nBytes, uint8_t polynomial, uint8_t init);
|
|
|
|
/// "Little-endian" Cyclic Redundancy Check CRC-8 LE
|
|
/// Input and output are reflected, i.e. least significant bit is shifted in first.
|
|
///
|
|
/// @param message array of bytes to check
|
|
/// @param nBytes number of bytes in message
|
|
/// @param polynomial CRC polynomial
|
|
/// @param init starting crc value
|
|
/// @return CRC value
|
|
uint8_t crc8le(uint8_t const message[], unsigned nBytes, uint8_t polynomial, uint8_t init);
|
|
|
|
/// CRC-16 LSB.
|
|
/// Input and output are reflected, i.e. least significant bit is shifted in first.
|
|
/// Note that poly and init already need to be reflected.
|
|
///
|
|
/// @param message array of bytes to check
|
|
/// @param nBytes number of bytes in message
|
|
/// @param polynomial CRC polynomial
|
|
/// @param init starting crc value
|
|
/// @return CRC value
|
|
uint16_t crc16lsb(uint8_t const message[], unsigned nBytes, uint16_t polynomial, uint16_t init);
|
|
|
|
/// CRC-16.
|
|
///
|
|
/// @param message array of bytes to check
|
|
/// @param nBytes number of bytes in message
|
|
/// @param polynomial CRC polynomial
|
|
/// @param init starting crc value
|
|
/// @return CRC value
|
|
uint16_t crc16(uint8_t const message[], unsigned nBytes, uint16_t polynomial, uint16_t init);
|
|
|
|
/// Digest-8 by "LFSR-based Toeplitz hash", bits MSB to LSB.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param bytes number of bytes to digest
|
|
/// @param gen key stream generator, needs to includes the MSB for ROR if the LFSR is rolling
|
|
/// @param key initial key
|
|
/// @return digest value
|
|
uint8_t lfsr_digest8(uint8_t const message[], unsigned bytes, uint8_t gen, uint8_t key);
|
|
|
|
/// Digest-8 by "LFSR-based Toeplitz hash", byte reversed, bits MSB to LSB.
|
|
///
|
|
/// @param message bytes of message data, read in reverse
|
|
/// @param bytes number of bytes to digest
|
|
/// @param gen key stream generator, needs to includes the MSB for ROR if the LFSR is rolling
|
|
/// @param key initial key
|
|
/// @return digest value
|
|
uint8_t lfsr_digest8_reverse(uint8_t const message[], int bytes, uint8_t gen, uint8_t key);
|
|
|
|
/// Digest-8 by "LFSR-based Toeplitz hash", byte reversed, bit reflect (LSB to MSB).
|
|
///
|
|
/// @param message bytes of message data, read in reverse
|
|
/// @param bytes number of bytes to digest
|
|
/// @param gen key stream generator, needs to includes the LSB for ROL if the LFSR is rolling
|
|
/// @param key initial key
|
|
/// @return digest value
|
|
uint8_t lfsr_digest8_reflect(uint8_t const message[], int bytes, uint8_t gen, uint8_t key);
|
|
|
|
/// Digest-16 by "LFSR-based Toeplitz hash".
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param bytes number of bytes to digest
|
|
/// @param gen key stream generator, needs to includes the MSB if the LFSR is rolling
|
|
/// @param key initial key
|
|
/// @return digest value
|
|
uint16_t lfsr_digest16(uint8_t const message[], unsigned bytes, uint16_t gen, uint16_t key);
|
|
|
|
/// Apply CCITT data whitening to a buffer.
|
|
///
|
|
/// The CCITT data whitening process is built around a 9-bit Linear Feedback Shift Register (LFSR).
|
|
/// The LFSR polynomial is the same polynomial as for IBM data whitening (x9 + x5 + 1).
|
|
/// The initial value of the data whitening key is set to all ones, 0x1FF.
|
|
/// s.a. https://www.nxp.com/docs/en/application-note/AN5070.pdf s.5.2
|
|
///
|
|
/// @param buffer bytes of message data
|
|
/// @param buffer_size number of bytes to process
|
|
void ccitt_whitening(uint8_t *buffer, unsigned buffer_size);
|
|
|
|
/// Compute bit parity of a single byte (8 bits).
|
|
///
|
|
/// @param byte single byte to check
|
|
/// @return 1 odd parity, 0 even parity
|
|
int parity8(uint8_t byte);
|
|
|
|
/// Compute bit parity of a number of bytes.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param num_bytes number of bytes to sum
|
|
/// @return 1 odd parity, 0 even parity
|
|
int parity_bytes(uint8_t const message[], unsigned num_bytes);
|
|
|
|
/// Compute XOR (byte-wide parity) of a number of bytes.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param num_bytes number of bytes to sum
|
|
/// @return summation value, per bit-position 1 odd parity, 0 even parity
|
|
uint8_t xor_bytes(uint8_t const message[], unsigned num_bytes);
|
|
|
|
/// Compute Addition of a number of bytes.
|
|
///
|
|
/// @param message bytes of message data
|
|
/// @param num_bytes number of bytes to sum
|
|
/// @return summation value
|
|
int add_bytes(uint8_t const message[], unsigned num_bytes);
|
|
|
|
/// Compute Addition of a number of nibbles (byte wise).
|
|
///
|
|
/// @param message bytes (of two nibbles) of message data
|
|
/// @param num_bytes number of bytes to sum
|
|
/// @return summation value
|
|
int add_nibbles(uint8_t const message[], unsigned num_bytes);
|
|
|
|
#endif /* INCLUDE_BIT_UTIL_H_ */
|