package com.intelligt.modbus.jlibmodbus.net.stream;
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import com.intelligt.modbus.jlibmodbus.exception.ModbusChecksumException;
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import com.intelligt.modbus.jlibmodbus.serial.SerialPort;
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import com.intelligt.modbus.jlibmodbus.utils.CRC16;
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import java.io.IOException;
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/*
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* Copyright (C) 2016 "Invertor" Factory", JSC
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* [http://www.sbp-invertor.ru]
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*
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* This file is part of JLibModbus.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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* Authors: Vladislav Y. Kochedykov, software engineer.
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* email: vladislav.kochedykov@gmail.com
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*/
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public class InputStreamRTU extends InputStreamSerial {
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private int crc = CRC16.INITIAL_VALUE;
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public InputStreamRTU(SerialPort serial) {
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super(serial);
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}
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@Override
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public void frameCheck() throws IOException, ModbusChecksumException {
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int c_crc = getCrc();
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int r_crc = readShortLE();
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if (c_crc != r_crc) {
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throw new ModbusChecksumException(r_crc, c_crc);
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}
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}
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@Override
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public void frameInit() {
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crc = CRC16.INITIAL_VALUE;
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}
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@Override
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public int read() throws IOException {
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int b = super.read();
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crc = CRC16.calc(crc, (byte) b);
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return b;
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}
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@Override
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public int read(byte[] b, int off, int len) throws IOException {
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int c = super.read(b, off, len);
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crc = CRC16.calc(crc, b, off, len);
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return c;
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}
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private int getCrc() {
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return crc;
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}
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}
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