97 lines
2.8 KiB
C++
97 lines
2.8 KiB
C++
/*
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* Copyright (C) 2015 Jared Boone, ShareBrained Technology, Inc.
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*
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* This file is part of PortaPack.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2, or (at your option)
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* any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; see the file COPYING. If not, write to
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* the Free Software Foundation, Inc., 51 Franklin Street,
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* Boston, MA 02110-1301, USA.
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*/
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#include "manchester.hpp"
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#include "string_format.hpp"
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size_t ManchesterBase::symbols_count() const {
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return packet.size() / 2;
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}
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DecodedSymbol ManchesterDecoder::operator[](const size_t index) const {
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const size_t encoded_index = index * 2;
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if( (encoded_index + 1) < packet.size() ) {
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const auto value = packet[encoded_index + sense];
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const auto error = packet[encoded_index + 0] == packet[encoded_index + 1];
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return { value, error };
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} else {
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return { 0, 1 };
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}
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}
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DecodedSymbol BiphaseMDecoder::operator[](const size_t index) const {
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const size_t encoded_index = index * 2;
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if( (encoded_index + 1) < packet.size() ) {
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const auto value = packet[encoded_index + 0] != packet[encoded_index + 1];
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const uint_fast8_t error = encoded_index ? (packet[encoded_index - 1] == packet[encoded_index + 0]) : 0;
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return { value, error };
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} else {
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return { 0, 1 };
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}
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}
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FormattedSymbols format_symbols(
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const ManchesterBase& decoder
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) {
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const size_t payload_length_decoded = decoder.symbols_count();
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const size_t payload_length_hex_characters = (payload_length_decoded + 3) / 4;
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const size_t payload_length_symbols_rounded = payload_length_hex_characters * 4;
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std::string hex_data;
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std::string hex_error;
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hex_data.reserve(payload_length_hex_characters);
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hex_error.reserve(payload_length_hex_characters);
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uint_fast8_t data = 0;
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uint_fast8_t error = 0;
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for(size_t i=0; i<payload_length_symbols_rounded; i++) {
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const auto symbol = decoder[i];
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data <<= 1;
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data |= symbol.value;
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error <<= 1;
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error |= symbol.error;
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if( (i & 3) == 3 ) {
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hex_data += to_string_hex(data & 0xf, 1);
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hex_error += to_string_hex(error & 0xf, 1);
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}
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}
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return { hex_data, hex_error };
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}
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void manchester_encode(uint8_t * dest, uint8_t * src, const size_t length, const size_t sense) {
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uint8_t part = sense ? 0 : 0xFF;
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for (size_t c = 0; c < length; c++) {
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if ((src[c >> 3] << (c & 7)) & 0x80) {
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*(dest++) = part;
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*(dest++) = ~part;
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} else {
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*(dest++) = ~part;
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*(dest++) = part;
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}
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}
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}
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