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/*! \file bits.h
* Osmocom bit level support code.
*
*/
#pragma once
#include <stdint.h>
#include <stddef.h>
#include <osmocom/core/bit16gen.h>
#include <osmocom/core/bit32gen.h>
#include <osmocom/core/bit64gen.h>
/*! \defgroup bits soft, unpacked and packed bits
* @{
* \file bits.h */
/*! soft bit with value (-127...127), as commonly used in
* communications receivers such as [viterbi] decoders */
typedef int8_t sbit_t;
/*! unpacked bit (0 or 1): 1 bit per byte */
typedef uint8_t ubit_t;
/*! packed bits (8 bits in a byte).
* NOTE on the endian-ness of \ref pbit_t:
* - Bits in a \ref pbit_t are ordered MSB first, i.e. 0x80 is the first bit.
* - Bit i in a \ref pbit_t array is array[i/8] & (1<<(7-i%8)) */
typedef uint8_t pbit_t;
/*! determine how many bytes we would need for \a num_bits packed bits
* \param[in] num_bits Number of packed bits
* \returns number of bytes needed for \a num_bits packed bits
*/
static inline unsigned int osmo_pbit_bytesize(unsigned int num_bits)
{
unsigned int pbit_bytesize = num_bits / 8;
if (num_bits % 8)
pbit_bytesize++;
return pbit_bytesize;
}
int osmo_ubit2pbit(pbit_t *out, const ubit_t *in, unsigned int num_bits);
int osmo_pbit2ubit(ubit_t *out, const pbit_t *in, unsigned int num_bits);
void osmo_nibble_shift_right(uint8_t *out, const uint8_t *in,
unsigned int num_nibbles);
void osmo_nibble_shift_left_unal(uint8_t *out, const uint8_t *in,
unsigned int num_nibbles);
void osmo_ubit2sbit(sbit_t *out, const ubit_t *in, unsigned int num_bits);
void osmo_sbit2ubit(ubit_t *out, const sbit_t *in, unsigned int num_bits);
int osmo_ubit2pbit_ext(pbit_t *out, unsigned int out_ofs,
const ubit_t *in, unsigned int in_ofs,
unsigned int num_bits, int lsb_mode);
int osmo_pbit2ubit_ext(ubit_t *out, unsigned int out_ofs,
const pbit_t *in, unsigned int in_ofs,
unsigned int num_bits, int lsb_mode);
#define OSMO_BIN_SPEC "%d%d%d%d%d%d%d%d"
#define OSMO_BIN_PRINT(byte) \
(byte & 0x80 ? 1 : 0), \
(byte & 0x40 ? 1 : 0), \
(byte & 0x20 ? 1 : 0), \
(byte & 0x10 ? 1 : 0), \
(byte & 0x08 ? 1 : 0), \
(byte & 0x04 ? 1 : 0), \
(byte & 0x02 ? 1 : 0), \
(byte & 0x01 ? 1 : 0)
#define OSMO_BIT_SPEC "%c%c%c%c%c%c%c%c"
#define OSMO_BIT_PRINT_EX(byte, ch) \
(byte & 0x80 ? ch : '.'), \
(byte & 0x40 ? ch : '.'), \
(byte & 0x20 ? ch : '.'), \
(byte & 0x10 ? ch : '.'), \
(byte & 0x08 ? ch : '.'), \
(byte & 0x04 ? ch : '.'), \
(byte & 0x02 ? ch : '.'), \
(byte & 0x01 ? ch : '.')
#define OSMO_BIT_PRINT(byte) OSMO_BIT_PRINT_EX(byte, '1')
/* BIT REVERSAL */
/*! bit-reversal mode for osmo_bit_reversal() */
enum osmo_br_mode {
/*! reverse all bits in a 32bit dword */
OSMO_BR_BITS_IN_DWORD = 31,
/*! reverse byte order in a 32bit dword */
OSMO_BR_BYTES_IN_DWORD = 24,
/*! reverse bits of each byte in a 32bit dword */
OSMO_BR_BITS_IN_BYTE = 7,
/*! swap the two 16bit words in a 32bit dword */
OSMO_BR_WORD_SWAP = 16,
};
uint32_t osmo_bit_reversal(uint32_t x, enum osmo_br_mode k);
uint32_t osmo_revbytebits_32(uint32_t x);
uint32_t osmo_revbytebits_8(uint8_t x);
void osmo_revbytebits_buf(uint8_t *buf, int len);
/*! left circular shift
* \param[in] in The 16 bit unsigned integer to be rotated
* \param[in] shift Number of bits to shift \a in to, [0;16] bits
* \returns shifted value
*/
static inline uint16_t osmo_rol16(uint16_t in, unsigned shift)
{
return (in << shift) | (in >> (16 - shift));
}
/*! @} */
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