flipperzero-firmware/applications/lfrfid/helpers/protocols/protocol_emmarin.cpp
あく 389ff92cc1
Naming and coding style convention, new linter tool. (#945)
* Makefile, Scripts: new linter
* About: remove ID from IC
* Firmware: remove double define for DIVC/DIVR
* Scripts: check folder names too. Docker: replace syntax check with make lint.
* Reformat Sources and Migrate to new file naming convention
* Docker: symlink clang-format-12 to clang-format
* Add coding style guide
2022-01-05 19:10:18 +03:00

151 lines
4.2 KiB
C++

#include "protocol_emmarin.h"
#include <furi.h>
#define EM_HEADER_POS 55
#define EM_HEADER_MASK (0x1FFLLU << EM_HEADER_POS)
#define EM_FIRST_ROW_POS 50
#define EM_ROW_COUNT 10
#define EM_COLUMN_COUNT 4
#define EM_BITS_PER_ROW_COUNT (EM_COLUMN_COUNT + 1)
#define EM_COLUMN_POS 4
#define EM_STOP_POS 0
#define EM_STOP_MASK (0x1LLU << EM_STOP_POS)
#define EM_HEADER_AND_STOP_MASK (EM_HEADER_MASK | EM_STOP_MASK)
#define EM_HEADER_AND_STOP_DATA (EM_HEADER_MASK)
typedef uint64_t EMMarinCardData;
void write_nibble(bool low_nibble, uint8_t data, EMMarinCardData* card_data) {
uint8_t parity_sum = 0;
uint8_t start = 0;
if(!low_nibble) start = 4;
for(int8_t i = (start + 3); i >= start; i--) {
parity_sum += (data >> i) & 1;
*card_data = (*card_data << 1) | ((data >> i) & 1);
}
*card_data = (*card_data << 1) | ((parity_sum % 2) & 1);
}
uint8_t ProtocolEMMarin::get_encoded_data_size() {
return sizeof(EMMarinCardData);
}
uint8_t ProtocolEMMarin::get_decoded_data_size() {
return 5;
}
void ProtocolEMMarin::encode(
const uint8_t* decoded_data,
const uint8_t decoded_data_size,
uint8_t* encoded_data,
const uint8_t encoded_data_size) {
furi_check(decoded_data_size >= get_decoded_data_size());
furi_check(encoded_data_size >= get_encoded_data_size());
EMMarinCardData card_data;
// header
card_data = 0b111111111;
// data
for(uint8_t i = 0; i < get_decoded_data_size(); i++) {
write_nibble(false, decoded_data[i], &card_data);
write_nibble(true, decoded_data[i], &card_data);
}
// column parity and stop bit
uint8_t parity_sum;
for(uint8_t c = 0; c < EM_COLUMN_COUNT; c++) {
parity_sum = 0;
for(uint8_t i = 1; i <= EM_ROW_COUNT; i++) {
uint8_t parity_bit = (card_data >> (i * EM_BITS_PER_ROW_COUNT - 1)) & 1;
parity_sum += parity_bit;
}
card_data = (card_data << 1) | ((parity_sum % 2) & 1);
}
// stop bit
card_data = (card_data << 1) | 0;
memcpy(encoded_data, &card_data, get_encoded_data_size());
}
void ProtocolEMMarin::decode(
const uint8_t* encoded_data,
const uint8_t encoded_data_size,
uint8_t* decoded_data,
const uint8_t decoded_data_size) {
furi_check(decoded_data_size >= get_decoded_data_size());
furi_check(encoded_data_size >= get_encoded_data_size());
uint8_t decoded_data_index = 0;
EMMarinCardData card_data = *(reinterpret_cast<const EMMarinCardData*>(encoded_data));
// clean result
memset(decoded_data, 0, decoded_data_size);
// header
for(uint8_t i = 0; i < 9; i++) {
card_data = card_data << 1;
}
// nibbles
uint8_t value = 0;
for(uint8_t r = 0; r < EM_ROW_COUNT; r++) {
uint8_t nibble = 0;
for(uint8_t i = 0; i < 5; i++) {
if(i < 4) nibble = (nibble << 1) | (card_data & (1LLU << 63) ? 1 : 0);
card_data = card_data << 1;
}
value = (value << 4) | nibble;
if(r % 2) {
decoded_data[decoded_data_index] |= value;
decoded_data_index++;
value = 0;
}
}
}
bool ProtocolEMMarin::can_be_decoded(const uint8_t* encoded_data, const uint8_t encoded_data_size) {
furi_check(encoded_data_size >= get_encoded_data_size());
const EMMarinCardData* card_data = reinterpret_cast<const EMMarinCardData*>(encoded_data);
// check header and stop bit
if((*card_data & EM_HEADER_AND_STOP_MASK) != EM_HEADER_AND_STOP_DATA) return false;
// check row parity
for(uint8_t i = 0; i < EM_ROW_COUNT; i++) {
uint8_t parity_sum = 0;
for(uint8_t j = 0; j < EM_BITS_PER_ROW_COUNT; j++) {
parity_sum += (*card_data >> (EM_FIRST_ROW_POS - i * EM_BITS_PER_ROW_COUNT + j)) & 1;
}
if((parity_sum % 2)) {
return false;
}
}
// check columns parity
for(uint8_t i = 0; i < EM_COLUMN_COUNT; i++) {
uint8_t parity_sum = 0;
for(uint8_t j = 0; j < EM_ROW_COUNT + 1; j++) {
parity_sum += (*card_data >> (EM_COLUMN_POS - i + j * EM_BITS_PER_ROW_COUNT)) & 1;
}
if((parity_sum % 2)) {
return false;
}
}
return true;
}