portapack-mayhem/firmware/baseband/packet_builder.hpp
2016-11-26 16:50:44 -08:00

140 lines
3.2 KiB
C++

/*
* Copyright (C) 2014 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.
*/
#ifndef __PACKET_BUILDER_H__
#define __PACKET_BUILDER_H__
#include <cstdint>
#include <cstddef>
#include <bitset>
#include <functional>
#include "bit_pattern.hpp"
#include "baseband_packet.hpp"
struct NeverMatch {
bool operator()(const BitHistory&, const size_t) const {
return false;
}
};
struct FixedLength {
bool operator()(const BitHistory&, const size_t symbols_received) const {
return symbols_received >= length;
}
const size_t length;
};
template<typename PreambleMatcher, typename UnstuffMatcher, typename EndMatcher>
class PacketBuilder {
public:
using PayloadHandlerFunc = std::function<void(const baseband::Packet& packet)>;
PacketBuilder(
const PreambleMatcher preamble_matcher,
const UnstuffMatcher unstuff_matcher,
const EndMatcher end_matcher,
PayloadHandlerFunc payload_handler
) : payload_handler { std::move(payload_handler) },
preamble(preamble_matcher),
unstuff(unstuff_matcher),
end(end_matcher)
{
}
void configure(
const PreambleMatcher preamble_matcher,
const UnstuffMatcher unstuff_matcher
) {
preamble = preamble_matcher;
unstuff = unstuff_matcher;
reset_state();
}
void execute(
const uint_fast8_t symbol
) {
bit_history.add(symbol);
switch(state) {
case State::Preamble:
if( preamble(bit_history, packet.size()) ) {
state = State::Payload;
}
break;
case State::Payload:
if( !unstuff(bit_history, packet.size()) ) {
packet.add(symbol);
}
if( end(bit_history, packet.size()) ) {
// NOTE: This check is to avoid std::function nullptr check, which
// brings in "_ZSt25__throw_bad_function_callv" and a lot of extra code.
// TODO: Make payload_handler known at compile time.
if( payload_handler ) {
packet.set_timestamp(Timestamp::now());
payload_handler(packet);
}
reset_state();
} else {
if( packet_truncated() ) {
reset_state();
}
}
break;
default:
reset_state();
break;
}
}
private:
enum State {
Preamble,
Payload,
};
bool packet_truncated() const {
return packet.size() >= packet.capacity();
}
const PayloadHandlerFunc payload_handler;
BitHistory bit_history { };
PreambleMatcher preamble { };
UnstuffMatcher unstuff { };
EndMatcher end { };
State state { State::Preamble };
baseband::Packet packet { };
void reset_state() {
packet.clear();
state = State::Preamble;
}
};
#endif/*__PACKET_BUILDER_H__*/