unleashed-firmware/lib/nfc/helpers/nfc_util.c
2024-07-16 01:01:17 +03:00

48 lines
1.6 KiB
C

#include "nfc_util.h"
#include <furi.h>
static const uint8_t nfc_util_odd_byte_parity[256] = {
1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0,
1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1,
1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1,
0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0,
1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1,
0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0,
0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1,
0, 1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1,
1, 0, 0, 1, 0, 1, 1, 0, 1, 0, 0, 1, 0, 1, 1, 0, 0, 1, 1, 0, 1, 0, 0, 1};
uint8_t nfc_util_even_parity32(uint32_t data) {
// data ^= data >> 16;
// data ^= data >> 8;
// return !nfc_util_odd_byte_parity[data];
return __builtin_parity(data) & 0xFF;
}
uint8_t nfc_util_odd_parity8(uint8_t data) {
return nfc_util_odd_byte_parity[data];
}
void nfc_util_odd_parity(const uint8_t* src, uint8_t* dst, uint8_t len) {
furi_check(src);
furi_check(dst);
uint8_t parity = 0;
uint8_t bit = 0;
while(len--) {
parity |= nfc_util_odd_parity8(*src) << (7 - bit); // parity is MSB first
bit++;
if(bit == 8) {
*dst = parity;
dst++;
parity = 0;
bit = 0;
}
src++;
}
if(bit) {
*dst = parity;
}
}