Move ERT, AIS packet code to common/.

firmware/common/ert_packet.cpp

@@ -0,0 +1,96 @@
+/*
+ * 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 "ert_packet.hpp"
+
+#include "crc.hpp"
+
+namespace ert {
+
+size_t Packet::length() const {
+	return decoder_.symbols_count();
+}
+
+bool Packet::is_valid() const {
+	return true;
+}
+
+rtc::RTC Packet::received_at() const {
+	return received_at_;
+}
+
+ERTPacketMessage::Type Packet::type() const {
+	return type_;
+}
+
+ID Packet::id() const {
+	if( type() == ERTPacketMessage::Type::SCM ) {
+		const auto msb = reader_.read(0, 2);
+		const auto lsb = reader_.read(35, 24);
+		return (msb << 24) | lsb;
+	}
+	if( type() == ERTPacketMessage::Type::IDM ) {
+		return reader_.read(5 * 8, 32);
+	}
+	return invalid_id;
+}
+
+Consumption Packet::consumption() const {
+	if( type() == ERTPacketMessage::Type::SCM ) {
+		return reader_.read(11, 24);
+	}
+	if( type() == ERTPacketMessage::Type::IDM ) {
+		return reader_.read(25 * 8, 32);
+	}
+	return invalid_consumption;
+}
+
+ManchesterFormatted Packet::symbols_formatted() const {
+	return format_manchester(decoder_);
+}
+
+bool Packet::crc_ok() const {
+	switch(type()) {
+	case ERTPacketMessage::Type::SCM:	return crc_ok_scm();
+	case ERTPacketMessage::Type::IDM:	return crc_ok_idm();
+	default:					return false;
+	}
+}
+
+bool Packet::crc_ok_scm() const {
+	CRC<uint16_t> ert_bch { 0x6f63 };
+	size_t start_bit = 5;
+	ert_bch.process_byte(reader_.read(0, start_bit));
+	for(size_t i=start_bit; i<length(); i+=8) {
+		ert_bch.process_byte(reader_.read(i, 8));
+	}
+	return ert_bch.checksum() == 0x0000;
+}
+
+bool Packet::crc_ok_idm() const {
+	CRC<uint16_t> ert_crc_ccitt { 0x1021, 0xffff, 0x1d0f };
+	for(size_t i=0; i<length(); i+=8) {
+		ert_crc_ccitt.process_byte(reader_.read(i, 8));
+	}
+	return ert_crc_ccitt.checksum() == 0x0000;
+}
+
+} /* namespace ert */