qdatastream.cpp

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#include "qdatastream.h"
#include "qdatastream_p.h"

#if !defined(QT_NO_DATASTREAM) || defined(QT_BOOTSTRAPPED)
#include "qbuffer.h"
#include "qstring.h"
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>
#include "qendian.h"

QT_BEGIN_NAMESPACE

/*****************************************************************************
  QDataStream member functions
 *****************************************************************************/

#undef  CHECK_STREAM_PRECOND
#ifndef QT_NO_DEBUG
#define CHECK_STREAM_PRECOND(retVal) \
    if (!dev) { \
        qWarning("QDataStream: No device"); \
        return retVal; \
    }
#else
#define CHECK_STREAM_PRECOND(retVal) \
    if (!dev) { \
        return retVal; \
    }
#endif

#define CHECK_STREAM_WRITE_PRECOND(retVal) \
    CHECK_STREAM_PRECOND(retVal) \
    if (q_status != Ok) \
        return retVal;

enum {
    DefaultStreamVersion = QDataStream::Qt_4_6
};

// ### 5.0: when streaming invalid QVariants, just the type should
// be written, no "data" after it

QDataStream::QDataStream()
{
    dev = 0;
    owndev = false;
    byteorder = BigEndian;
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}

QDataStream::QDataStream(QIODevice *d)
{
    dev = d;                                // set device
    owndev = false;
    byteorder = BigEndian;                        // default byte order
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}

#ifdef QT3_SUPPORT

QDataStream::QDataStream(QByteArray *a, int mode)
{
    QBuffer *buf = new QBuffer(a);
#ifndef QT_NO_QOBJECT
    buf->blockSignals(true);
#endif
    buf->open(QIODevice::OpenMode(mode));
    dev = buf;
    owndev = true;
    byteorder = BigEndian;
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}
#endif

QDataStream::QDataStream(QByteArray *a, QIODevice::OpenMode flags)
{
    QBuffer *buf = new QBuffer(a);
#ifndef QT_NO_QOBJECT
    buf->blockSignals(true);
#endif
    buf->open(flags);
    dev = buf;
    owndev = true;
    byteorder = BigEndian;
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}

QDataStream::QDataStream(const QByteArray &a)
{
    QBuffer *buf = new QBuffer;
#ifndef QT_NO_QOBJECT
    buf->blockSignals(true);
#endif
    buf->setData(a);
    buf->open(QIODevice::ReadOnly);
    dev = buf;
    owndev = true;
    byteorder = BigEndian;
    ver = DefaultStreamVersion;
    noswap = QSysInfo::ByteOrder == QSysInfo::BigEndian;
    q_status = Ok;
}

QDataStream::~QDataStream()
{
    if (owndev)
        delete dev;
}


void QDataStream::setDevice(QIODevice *d)
{
    if (owndev) {
        delete dev;
        owndev = false;
    }
    dev = d;
}

void QDataStream::unsetDevice()
{
    setDevice(0);
}


bool QDataStream::atEnd() const
{
    return dev ? dev->atEnd() : true;
}

QDataStream::FloatingPointPrecision QDataStream::floatingPointPrecision() const
{
    return d == 0 ? QDataStream::DoublePrecision : d->floatingPointPrecision;
}

void QDataStream::setFloatingPointPrecision(QDataStream::FloatingPointPrecision precision)
{
    if (d == 0)
        d.reset(new QDataStreamPrivate());
    d->floatingPointPrecision = precision;
}

QDataStream::Status QDataStream::status() const
{
    return q_status;
}

void QDataStream::resetStatus()
{
    q_status = Ok;
}

void QDataStream::setStatus(Status status)
{
    if (q_status == Ok)
        q_status = status;
}

void QDataStream::setByteOrder(ByteOrder bo)
{
    byteorder = bo;
    if (QSysInfo::ByteOrder == QSysInfo::BigEndian)
        noswap = (byteorder == BigEndian);
    else
        noswap = (byteorder == LittleEndian);
}


/*****************************************************************************
  QDataStream read functions
 *****************************************************************************/

QDataStream &QDataStream::operator>>(qint8 &i)
{
    i = 0;
    CHECK_STREAM_PRECOND(*this)
    char c;
    if (!dev->getChar(&c))
        setStatus(ReadPastEnd);
    else
        i = qint8(c);
    return *this;
}


QDataStream &QDataStream::operator>>(qint16 &i)
{
    i = 0;
    CHECK_STREAM_PRECOND(*this)
    if (dev->read((char *)&i, 2) != 2) {
        i = 0;
        setStatus(ReadPastEnd);
    } else {
        if (!noswap) {
            i = qbswap(i);
        }
    }
    return *this;
}


QDataStream &QDataStream::operator>>(qint32 &i)
{
    i = 0;
    CHECK_STREAM_PRECOND(*this)
    if (dev->read((char *)&i, 4) != 4) {
        i = 0;
        setStatus(ReadPastEnd);
    } else {
        if (!noswap) {
            i = qbswap(i);
        }
    }
    return *this;
}

QDataStream &QDataStream::operator>>(qint64 &i)
{
    i = qint64(0);
    CHECK_STREAM_PRECOND(*this)
    if (version() < 6) {
        quint32 i1, i2;
        *this >> i2 >> i1;
        i = ((quint64)i1 << 32) + i2;
    } else {
        if (dev->read((char *)&i, 8) != 8) {
            i = qint64(0);
            setStatus(ReadPastEnd);
        } else {
            if (!noswap) {
                i = qbswap(i);
            }
        }
    }
    return *this;
}

QDataStream &QDataStream::operator>>(bool &i)
{
    qint8 v;
    *this >> v;
    i = !!v;
    return *this;
}

QDataStream &QDataStream::operator>>(float &f)
{    
    if (version() >= QDataStream::Qt_4_6
        && floatingPointPrecision() == QDataStream::DoublePrecision) {
        double d;
        *this >> d;
        f = d;
        return *this;
    }

    f = 0.0f;
    CHECK_STREAM_PRECOND(*this)
    if (dev->read((char *)&f, 4) != 4) {
        f = 0.0f;
        setStatus(ReadPastEnd);
    } else {
        if (!noswap) {
            union {
                float val1;
                quint32 val2;
            } x;
            x.val2 = qbswap(*reinterpret_cast<quint32 *>(&f));
            f = x.val1;
        }
    }
    return *this;
}

#if defined(Q_DOUBLE_FORMAT)
#define Q_DF(x) Q_DOUBLE_FORMAT[(x)] - '0'
#endif

QDataStream &QDataStream::operator>>(double &f)
{
    if (version() >= QDataStream::Qt_4_6
        && floatingPointPrecision() == QDataStream::SinglePrecision) {
        float d;
        *this >> d;
        f = d;
        return *this;
    }

    f = 0.0;
    CHECK_STREAM_PRECOND(*this)
#ifndef Q_DOUBLE_FORMAT
    if (dev->read((char *)&f, 8) != 8) {
        f = 0.0;
        setStatus(ReadPastEnd);
    } else {
        if (!noswap) {
            union {
                double val1;
                quint64 val2;
            } x;
            x.val2 = qbswap(*reinterpret_cast<quint64 *>(&f));
            f = x.val1;
        }
    }
#else
    //non-standard floating point format
    union {
        double val1;
        char val2[8];
    } x;
    char *p = x.val2;
    char b[8];
    if (dev->read(b, 8) == 8) {
        if (noswap) {
            *p++ = b[Q_DF(0)];
            *p++ = b[Q_DF(1)];
            *p++ = b[Q_DF(2)];
            *p++ = b[Q_DF(3)];
            *p++ = b[Q_DF(4)];
            *p++ = b[Q_DF(5)];
            *p++ = b[Q_DF(6)];
            *p = b[Q_DF(7)];
        } else {
            *p++ = b[Q_DF(7)];
            *p++ = b[Q_DF(6)];
            *p++ = b[Q_DF(5)];
            *p++ = b[Q_DF(4)];
            *p++ = b[Q_DF(3)];
            *p++ = b[Q_DF(2)];
            *p++ = b[Q_DF(1)];
            *p = b[Q_DF(0)];
        }
        f = x.val1;
    } else {
        setStatus(ReadPastEnd);
    }
#endif
    return *this;
}


QDataStream &QDataStream::operator>>(char *&s)
{
    uint len = 0;
    return readBytes(s, len);
}


QDataStream &QDataStream::readBytes(char *&s, uint &l)
{
    s = 0;
    l = 0;
    CHECK_STREAM_PRECOND(*this)

    quint32 len;
    *this >> len;
    if (len == 0)
        return *this;

    const quint32 Step = 1024 * 1024;
    quint32 allocated = 0;
    char *prevBuf = 0;
    char *curBuf = 0;

    do {
        int blockSize = qMin(Step, len - allocated);
        prevBuf = curBuf;
        curBuf = new char[allocated + blockSize + 1];
        if (prevBuf) {
            memcpy(curBuf, prevBuf, allocated);
            delete [] prevBuf;
        }
        if (dev->read(curBuf + allocated, blockSize) != blockSize) {
            delete [] curBuf;
            setStatus(ReadPastEnd);
            return *this;
        }
        allocated += blockSize;
    } while (allocated < len);

    s = curBuf;
    s[len] = '\0';
    l = (uint)len;
    return *this;
}

int QDataStream::readRawData(char *s, int len)
{
    CHECK_STREAM_PRECOND(-1)
    return dev->read(s, len);
}


/*****************************************************************************
  QDataStream write functions
 *****************************************************************************/


QDataStream &QDataStream::operator<<(qint8 i)
{
    CHECK_STREAM_WRITE_PRECOND(*this)
    if (!dev->putChar(i))
        q_status = WriteFailed;
    return *this;
}


QDataStream &QDataStream::operator<<(qint16 i)
{
    CHECK_STREAM_WRITE_PRECOND(*this)
    if (!noswap) {
        i = qbswap(i);
    }
    if (dev->write((char *)&i, sizeof(qint16)) != sizeof(qint16))
        q_status = WriteFailed;
    return *this;
}

QDataStream &QDataStream::operator<<(qint32 i)
{
    CHECK_STREAM_WRITE_PRECOND(*this)
    if (!noswap) {
        i = qbswap(i);
    }
    if (dev->write((char *)&i, sizeof(qint32)) != sizeof(qint32))
        q_status = WriteFailed;
    return *this;
}

QDataStream &QDataStream::operator<<(qint64 i)
{
    CHECK_STREAM_WRITE_PRECOND(*this)
    if (version() < 6) {
        quint32 i1 = i & 0xffffffff;
        quint32 i2 = i >> 32;
        *this << i2 << i1;
    } else {
        if (!noswap) {
            i = qbswap(i);
        }
        if (dev->write((char *)&i, sizeof(qint64)) != sizeof(qint64))
            q_status = WriteFailed;
    }
    return *this;
}

QDataStream &QDataStream::operator<<(bool i)
{
    CHECK_STREAM_WRITE_PRECOND(*this)
    if (!dev->putChar(qint8(i)))
        q_status = WriteFailed;
    return *this;
}

QDataStream &QDataStream::operator<<(float f)
{
    if (version() >= QDataStream::Qt_4_6
        && floatingPointPrecision() == QDataStream::DoublePrecision) {
        *this << double(f);
        return *this;
    }

    CHECK_STREAM_WRITE_PRECOND(*this)
    float g = f;                                // fixes float-on-stack problem
    if (!noswap) {
        union {
            float val1;
            quint32 val2;
        } x;
        x.val1 = g;
        x.val2 = qbswap(x.val2);

        if (dev->write((char *)&x.val2, sizeof(float)) != sizeof(float))
            q_status = WriteFailed;
        return *this;
    }

    if (dev->write((char *)&g, sizeof(float)) != sizeof(float))
        q_status = WriteFailed;
    return *this;
}


QDataStream &QDataStream::operator<<(double f)
{
    if (version() >= QDataStream::Qt_4_6
        && floatingPointPrecision() == QDataStream::SinglePrecision) {
        *this << float(f);
        return *this;
    }

    CHECK_STREAM_WRITE_PRECOND(*this)
#ifndef Q_DOUBLE_FORMAT
    if (noswap) {
        if (dev->write((char *)&f, sizeof(double)) != sizeof(double))
            q_status = WriteFailed;
    } else {
        union {
            double val1;
            quint64 val2;
        } x;
        x.val1 = f;
        x.val2 = qbswap(x.val2);
        if (dev->write((char *)&x.val2, sizeof(double)) != sizeof(double))
            q_status = WriteFailed;
    }
#else
    union {
        double val1;
        char val2[8];
    } x;
    x.val1 = f;
    char *p = x.val2;
    char b[8];
    if (noswap) {
        b[Q_DF(0)] = *p++;
        b[Q_DF(1)] = *p++;
        b[Q_DF(2)] = *p++;
        b[Q_DF(3)] = *p++;
        b[Q_DF(4)] = *p++;
        b[Q_DF(5)] = *p++;
        b[Q_DF(6)] = *p++;
        b[Q_DF(7)] = *p;
    } else {
        b[Q_DF(7)] = *p++;
        b[Q_DF(6)] = *p++;
        b[Q_DF(5)] = *p++;
        b[Q_DF(4)] = *p++;
        b[Q_DF(3)] = *p++;
        b[Q_DF(2)] = *p++;
        b[Q_DF(1)] = *p++;
        b[Q_DF(0)] = *p;
    }
    if (dev->write(b, 8) != 8)
        q_status = WriteFailed;
#endif
    return *this;
}


QDataStream &QDataStream::operator<<(const char *s)
{
    if (!s) {
        *this << (quint32)0;
        return *this;
    }
    uint len = qstrlen(s) + 1;                        // also write null terminator
    *this << (quint32)len;                        // write length specifier
    writeRawData(s, len);
    return *this;
}


QDataStream &QDataStream::writeBytes(const char *s, uint len)
{
    CHECK_STREAM_WRITE_PRECOND(*this)
    *this << (quint32)len;                        // write length specifier
    if (len)
        writeRawData(s, len);
    return *this;
}


int QDataStream::writeRawData(const char *s, int len)
{
    CHECK_STREAM_WRITE_PRECOND(-1)
    int ret = dev->write(s, len);
    if (ret != len)
        q_status = WriteFailed;
    return ret;
}

int QDataStream::skipRawData(int len)
{
    CHECK_STREAM_PRECOND(-1)

    if (dev->isSequential()) {
        char buf[4096];
        int sumRead = 0;

        while (len > 0) {
            int blockSize = qMin(len, (int)sizeof(buf));
            int n = dev->read(buf, blockSize);
            if (n == -1)
                return -1;
            if (n == 0)
                return sumRead;

            sumRead += n;
            len -= blockSize;
        }
        return sumRead;
    } else {
        qint64 pos = dev->pos();
        qint64 size = dev->size();
        if (pos + len > size)
            len = size - pos;
        if (!dev->seek(pos + len))
            return -1;
        return len;
    }
}

#ifdef QT3_SUPPORT

#endif

QT_END_NAMESPACE

#endif // QT_NO_DATASTREAM