1 /**************************************************************************** 2 ** 3 ** Copyright (C) 2017 The Qt Company Ltd. 4 ** Contact: http://www.qt.io/licensing/ 5 ** 6 ** This file is part of the QtSerialBus module of the Qt Toolkit. 7 ** 8 ** $QT_BEGIN_LICENSE:LGPL3$ 9 ** Commercial License Usage 10 ** Licensees holding valid commercial Qt licenses may use this file in 11 ** accordance with the commercial license agreement provided with the 12 ** Software or, alternatively, in accordance with the terms contained in 13 ** a written agreement between you and The Qt Company. For licensing terms 14 ** and conditions see http://www.qt.io/terms-conditions. For further 15 ** information use the contact form at http://www.qt.io/contact-us. 16 ** 17 ** GNU Lesser General Public License Usage 18 ** Alternatively, this file may be used under the terms of the GNU Lesser 19 ** General Public License version 3 as published by the Free Software 20 ** Foundation and appearing in the file LICENSE.LGPLv3 included in the 21 ** packaging of this file. Please review the following information to 22 ** ensure the GNU Lesser General Public License version 3 requirements 23 ** will be met: https://www.gnu.org/licenses/lgpl.html. 24 ** 25 ** GNU General Public License Usage 26 ** Alternatively, this file may be used under the terms of the GNU 27 ** General Public License version 2.0 or later as published by the Free 28 ** Software Foundation and appearing in the file LICENSE.GPL included in 29 ** the packaging of this file. Please review the following information to 30 ** ensure the GNU General Public License version 2.0 requirements will be 31 ** met: http://www.gnu.org/licenses/gpl-2.0.html. 32 ** 33 ** $QT_END_LICENSE$ 34 ** 35 ****************************************************************************/ 36 37 #ifndef QMODBUSADU_P_H 38 #define QMODBUSADU_P_H 39 40 #include <QtSerialBus/qmodbuspdu.h> 41 42 // 43 // W A R N I N G 44 // ------------- 45 // 46 // This file is not part of the Qt API. It exists purely as an 47 // implementation detail. This header file may change from version to 48 // version without notice, or even be removed. 49 // 50 // We mean it. 51 // 52 53 QT_BEGIN_NAMESPACE 54 55 class QModbusSerialAdu 56 { 57 public: 58 enum Type { 59 Ascii, 60 Rtu 61 }; 62 QModbusSerialAdu(Type type,const QByteArray & data)63 inline QModbusSerialAdu(Type type, const QByteArray &data) 64 : m_type(type), m_data(data), m_rawData(data) 65 { 66 if (m_type == Ascii) 67 m_data = QByteArray::fromHex(m_data.mid(1, m_data.size() - 3)); 68 } 69 size()70 inline int size() const { 71 if (m_type == Ascii) 72 return m_data.size() - 1; // one byte, LRC 73 return m_data.size() - 2; // two bytes, CRC 74 } data()75 inline QByteArray data() const { return m_data.left(size()); } 76 rawSize()77 inline int rawSize() const { return m_rawData.size(); } rawData()78 inline QByteArray rawData() const { return m_rawData; } 79 serverAddress()80 inline int serverAddress() const { 81 Q_ASSERT_X(!m_data.isEmpty(), "QModbusAdu::serverAddress()", "Empty ADU."); 82 return quint8(m_data.at(0)); 83 } 84 pdu()85 inline QModbusPdu pdu() const { 86 Q_ASSERT_X(!m_data.isEmpty(), "QModbusAdu::pdu()", "Empty ADU."); 87 return QModbusPdu(QModbusPdu::FunctionCode(m_data.at(1)), m_data.mid(2, size() - 2)); 88 } 89 90 template <typename T> 91 auto checksum() const -> decltype(T()) { 92 Q_ASSERT_X(!m_data.isEmpty(), "QModbusAdu::checksum()", "Empty ADU."); 93 if (m_type == Ascii) 94 return quint8(m_data[m_data.size() - 1]); 95 return quint16(quint8(m_data[m_data.size() - 2]) << 8 | quint8(m_data[m_data.size() - 1])); 96 } 97 matchingChecksum()98 inline bool matchingChecksum() const { 99 Q_ASSERT_X(!m_data.isEmpty(), "QModbusAdu::matchingChecksum()", "Empty ADU."); 100 if (m_type == Ascii) 101 return QModbusSerialAdu::calculateLRC(data(), size()) == checksum<quint8>(); 102 return QModbusSerialAdu::calculateCRC(data(), size()) == checksum<quint16>(); 103 } 104 105 /*! 106 \internal 107 \fn quint8 QModbusSerialAdu::calculateLRC(const char *data, qint32 len) 108 109 Returns the LRC checksum of the first \a len bytes of \a data. The checksum is independent 110 of the byte order (endianness). 111 */ calculateLRC(const char * data,qint32 len)112 inline static quint8 calculateLRC(const char *data, qint32 len) 113 { 114 quint32 lrc = 0; 115 while (len--) 116 lrc += *data++; 117 return -(quint8(lrc)); 118 } 119 120 /*! 121 \internal 122 \fn quint16 QModbusSerialAdu::calculateCRC(const char *data, qint32 len) const 123 124 Returns the CRC checksum of the first \a len bytes of \a data. 125 126 \note The code used by the function was generated with pycrc. There is no copyright assigned 127 to the generated code, however, the author of the script requests to show the line stating 128 that the code was generated by pycrc (see implementation). 129 */ calculateCRC(const char * data,qint32 len)130 inline static quint16 calculateCRC(const char *data, qint32 len) 131 { 132 // Generated by pycrc v0.8.3, https://pycrc.org 133 // Width = 16, Poly = 0x8005, XorIn = 0xffff, ReflectIn = True, 134 // XorOut = 0x0000, ReflectOut = True, Algorithm = bit-by-bit-fast 135 136 quint16 crc = 0xFFFF; 137 while (len--) { 138 const quint8 c = *data++; 139 for (qint32 i = 0x01; i & 0xFF; i <<= 1) { 140 bool bit = crc & 0x8000; 141 if (c & i) 142 bit = !bit; 143 crc <<= 1; 144 if (bit) 145 crc ^= 0x8005; 146 } 147 crc &= 0xFFFF; 148 } 149 crc = crc_reflect(crc & 0xFFFF, 16) ^ 0x0000; 150 return (crc >> 8) | (crc << 8); // swap bytes 151 } 152 153 inline static QByteArray create(Type type, int serverAddress, const QModbusPdu &pdu, 154 char delimiter = '\n') { 155 QByteArray result; 156 QDataStream out(&result, QIODevice::WriteOnly); 157 out << quint8(serverAddress) << pdu; 158 159 if (type == Ascii) { 160 out << calculateLRC(result, result.size()); 161 return ":" + result.toHex() + "\r" + delimiter; 162 } else { 163 out << calculateCRC(result, result.size()); 164 } 165 return result; 166 } 167 168 private: crc_reflect(quint16 data,qint32 len)169 inline static quint16 crc_reflect(quint16 data, qint32 len) 170 { 171 // Generated by pycrc v0.8.3, https://pycrc.org 172 // Width = 16, Poly = 0x8005, XorIn = 0xffff, ReflectIn = True, 173 // XorOut = 0x0000, ReflectOut = True, Algorithm = bit-by-bit-fast 174 175 quint16 ret = data & 0x01; 176 for (qint32 i = 1; i < len; i++) { 177 data >>= 1; 178 ret = (ret << 1) | (data & 0x01); 179 } 180 return ret; 181 } 182 183 private: 184 Type m_type = Rtu; 185 QByteArray m_data; 186 QByteArray m_rawData; 187 }; 188 189 QT_END_NAMESPACE 190 191 #endif // QMODBUSADU_P_H 192