portapack-mayhem/firmware/application/manchester.cpp
2015-12-02 13:38:17 -08:00

72 lines
2.1 KiB
C++

/*
* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
*
* This file is part of PortaPack.
*
* 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, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; see the file COPYING. If not, write to
* the Free Software Foundation, Inc., 51 Franklin Street,
* Boston, MA 02110-1301, USA.
*/
#include "manchester.hpp"
#include "string_format.hpp"
ManchesterDecoder::DecodedSymbol ManchesterDecoder::operator[](const size_t index) const {
const size_t encoded_index = index * 2;
if( (encoded_index + 1) < count ) {
const auto value = encoded[encoded_index + sense];
const auto error = encoded[encoded_index + 0] == encoded[encoded_index + 1];
return { value, error };
} else {
return { 0, 1 };
}
}
size_t ManchesterDecoder::symbols_count() const {
return count / 2;
}
ManchesterFormatted format_manchester(
const ManchesterDecoder& decoder
) {
const size_t payload_length_decoded = decoder.symbols_count();
const size_t payload_length_hex_characters = (payload_length_decoded + 3) / 4;
const size_t payload_length_symbols_rounded = payload_length_hex_characters * 4;
std::string hex_data;
std::string hex_error;
hex_data.reserve(payload_length_hex_characters);
hex_error.reserve(payload_length_hex_characters);
uint_fast8_t data = 0;
uint_fast8_t error = 0;
for(size_t i=0; i<payload_length_symbols_rounded; i++) {
const auto symbol = decoder[i];
data <<= 1;
data |= symbol.value;
error <<= 1;
error |= symbol.error;
if( (i & 3) == 3 ) {
hex_data += to_string_hex(data & 0xf, 1);
hex_error += to_string_hex(error & 0xf, 1);
}
}
return { hex_data, hex_error };
}