qserialport.cpp

/****************************************************************************
**
** Copyright (C) 2011-2012 Denis Shienkov <denis.shienkov@gmail.com>
** Copyright (C) 2011 Sergey Belyashov <Sergey.Belyashov@gmail.com>
** Copyright (C) 2012 Laszlo Papp <lpapp@kde.org>
** Copyright (C) 2012 Andre Hartmann <aha_1980@gmx.de>
** Contact: http://www.qt-project.org/legal
**
** This file is part of the QtSerialPort module of the Qt Toolkit.
**
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#include "qserialport.h"
#include "qserialportinfo.h"

#ifdef Q_OS_WIN
#include "qserialport_win_p.h"
#elif defined (Q_OS_SYMBIAN)
#include "qserialport_symbian_p.h"
#elif defined (Q_OS_UNIX)
#include "qserialport_unix_p.h"
#else
#error Unsupported OS
#endif

#ifndef SERIALPORT_BUFFERSIZE
#  define SERIALPORT_BUFFERSIZE 16384
#endif

QT_BEGIN_NAMESPACE

QSerialPortPrivateData::QSerialPortPrivateData(QSerialPort *q)
    : readBufferMaxSize(0)
    , readBuffer(SERIALPORT_BUFFERSIZE)
    , writeBuffer(SERIALPORT_BUFFERSIZE)
    , error(QSerialPort::NoError)
    , inputBaudRate(0)
    , outputBaudRate(0)
    , dataBits(QSerialPort::UnknownDataBits)
    , parity(QSerialPort::UnknownParity)
    , stopBits(QSerialPort::UnknownStopBits)
    , flow(QSerialPort::UnknownFlowControl)
    , policy(QSerialPort::IgnorePolicy)
    , settingsRestoredOnClose(true)
    , q_ptr(q)
{
}

int QSerialPortPrivateData::timeoutValue(int msecs, int elapsed)
{
    if (msecs == -1)
        return msecs;
    msecs -= elapsed;
    return qMax(msecs, 0);
}

/*!
    \class QSerialPort

    \brief Provides functions to access serial ports.

    \reentrant
    \ingroup serialport-main
    \inmodule QtSerialPort
    \since 5.1

    You can get information about the available serial ports using the
    QSerialPortInfo helper class, which allows an enumeration of all the serial
    ports in the system. This is useful to obtain the correct name of the
    serial port you want to use. You can pass an object
    of the helper class as an argument to the setPort() or setPortName()
    methods to assign the desired serial device.

    After setting the port, you can open it in read-only (r/o), write-only
    (w/o), or read-write (r/w) mode using the open() method.

    \note The serial port is always opened with exclusive access
    (that is, no other process or thread can access an already opened serial port).

    Having successfully opened, QSerialPort tries to determine the current
    configuration of the port and initializes itself. You can reconfigure the
    port to the desired setting using the setBaudRate(), setDataBits(),
    setParity(), setStopBits(), and setFlowControl() methods.

    The status of the control pinout signals is determined with the
    isDataTerminalReady(), isRequestToSend, and pinoutSignals() methods. To
    change the control line status, use the setDataTerminalReady(), and
    setRequestToSend() methods.

    Once you know that the ports are ready to read or write, you can
    use the read() or write() methods. Alternatively the
    readLine() and readAll() convenience methods can also be invoked.
    If not all the data is read at once, the remaining data will
    be available for later as new incoming data is appended to the
    QSerialPort's internal read buffer. You can limit the size of the read
    buffer using setReadBufferSize().

    Use the close() method to close the port and cancel the I/O operations.

    See the following example:

    \code
     int numRead = 0, numReadTotal = 0;
     char buffer[50];

     forever {
         numRead  = serial.read(buffer, 50);

         // Do whatever with the array

         numReadTotal += numRead;
         if (numRead == 0 && !serial.waitForReadyRead())
             break;
     }
    \endcode

    If \l{QIODevice::}{waitForReadyRead()} returns false, the
    connection has been closed or an error has occurred.

    Programming with a blocking serial port is radically different from
    programming with a non-blocking serial port. A blocking serial port
    does not require an event loop and typically leads to simpler code.
    However, in a GUI application, blocking serial port should only be
    used in non-GUI threads, to avoid freezing the user interface.

    For more details about these approaches, refer to the
    \l {Examples}{example} applications.

    The QSerialPort class can also be used with QTextStream and QDataStream's
    stream operators (operator<<() and operator>>()). There is one issue to be
    aware of, though: make sure that enough data is available before attempting
    to read by using the operator>>() overloaded operator.

    \sa QSerialPortInfo
*/

/*!
    \enum QSerialPort::Direction

    This enum describes the possible directions of the data transmission.

    \note This enumeration is used for setting the baud rate of the device
    separately for each direction on some operating systems (for example,
    POSIX-like).

    \value Input            Input direction.
    \value Output           Output direction.
    \value AllDirections    Simultaneously in two directions.
*/

/*!
    \enum QSerialPort::BaudRate

    This enum describes the baud rate which the communication device operates
    with. Note: only the most common standard baud rates are listed in this
    enum.

    \value Baud1200     1200 baud.
    \value Baud2400     2400 baud.
    \value Baud4800     4800 baud.
    \value Baud9600     9600 baud.
    \value Baud19200    19200 baud.
    \value Baud38400    38400 baud.
    \value Baud57600    57600 baud.
    \value Baud115200   115200 baud.
    \value UnknownBaud  Unknown baud.

    \sa QSerialPort::baudRate