qtextstream.cpp

奇趣公司比较新的qt/emd版本

    state->d = 0;
}

static void copyConverterState(QTextCodec::ConverterState *dest, const QTextCodec::ConverterState *src)
{
    // ### QTextCodec::ConverterState's copy constructors and assignments are
    // private. This function copies the structure manually.
    dest->flags = src->flags;
    dest->invalidChars = src->invalidChars;
    dest->state_data[0] = src->state_data[0];
    dest->state_data[1] = src->state_data[1];
    dest->state_data[2] = src->state_data[2];
    dest->d = src->d; // <- ### wrong?
}
#endif

/*! \internal
*/
void QTextStreamPrivate::reset()
{
    realNumberPrecision = 6;
    integerBase = 0;
    fieldWidth = 0;
    padChar = QLatin1Char(' ');
    fieldAlignment = QTextStream::AlignRight;
    realNumberNotation = QTextStream::SmartNotation;
    numberFlags = 0;

    device = 0;
    deleteDevice = false;
    string = 0;
    stringOffset = 0;
    stringOpenMode = QIODevice::NotOpen;

    readBufferOffset = 0;
    readBufferStartDevicePos = 0;
    lastTokenSize = 0;

#ifndef QT_NO_TEXTCODEC
    codec = QTextCodec::codecForLocale();
    ::resetCodecConverterState(&readConverterState);
    ::resetCodecConverterState(&writeConverterState);
    ::resetCodecConverterState(&readBufferStartReadConverterState);
    writeConverterState.flags |= QTextCodec::IgnoreHeader;
    autoDetectUnicode = true;
#endif
}

/*! \internal
*/
bool QTextStreamPrivate::fillReadBuffer(qint64 maxBytes)
{
    // no buffer next to the QString itself; this function should only
    // be called internally, for devices.
    Q_ASSERT(!string);
    Q_ASSERT(device);

    // handle text translation and bypass the Text flag in the device.
    bool textModeEnabled = device->isTextModeEnabled();
    if (textModeEnabled)
        device->setTextModeEnabled(false);

    // read raw data into a temporary buffer
    char buf[QTEXTSTREAM_BUFFERSIZE];
    qint64 bytesRead = 0;
#if defined(Q_OS_WIN)
    // On Windows, there is no non-blocking stdin - so we fall back to reading
    // lines instead. If there is no QOBJECT, we read lines for all sequential
    // devices; otherwise, we read lines only for stdin.
    QFile *file = 0;
    Q_UNUSED(file);
    if (device->isSequential()
#if !defined(QT_NO_QOBJECT)
        && (file = qobject_cast<QFile *>(device)) && file->handle() == 0
#endif
        ) {
        if (maxBytes != -1)
            bytesRead = device->readLine(buf, qMin<qint64>(sizeof(buf), maxBytes));
        else
            bytesRead = device->readLine(buf, sizeof(buf));
    } else
#endif
    {
        if (maxBytes != -1)
            bytesRead = device->read(buf, qMin<qint64>(sizeof(buf), maxBytes));
        else
            bytesRead = device->read(buf, sizeof(buf));
    }

#ifndef QT_NO_TEXTCODEC
    // codec auto detection, explicitly defaults to locale encoding if the
    // codec has been set to 0.
    if (!codec || autoDetectUnicode) {
        autoDetectUnicode = false;
        
        if (bytesRead >= 2 && (uchar(buf[0]) == 0xff && uchar(buf[1]) == 0xfe
                               || uchar(buf[0]) == 0xfe && uchar(buf[1]) == 0xff)) {
            codec = QTextCodec::codecForName("UTF-16");
        } else if (!codec) {
            codec = QTextCodec::codecForLocale();
            writeConverterState.flags |= QTextCodec::IgnoreHeader;
        }
    }
#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStreamPrivate::fillReadBuffer(), using %s codec",
           codec->name().constData());
#endif
#endif

#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStreamPrivate::fillReadBuffer(), device->read(\"%s\", %d) == %d",
           qt_prettyDebug(buf, qMin(32,int(bytesRead)) , int(bytesRead)).constData(), sizeof(buf), int(bytesRead));
#endif
    
    if (bytesRead <= 0)
        return false;

    int oldReadBufferSize = readBuffer.size();
#ifndef QT_NO_TEXTCODEC
    // convert to unicode
    readBuffer += codec->toUnicode(buf, bytesRead, &readConverterState);
#else
    readBuffer += QString::fromLatin1(QByteArray(buf, bytesRead).constData());
#endif

    // reset the Text flag.
    if (textModeEnabled)
        device->setTextModeEnabled(true);

    // remove all '\r\n' in the string.
    if (readBuffer.size() > oldReadBufferSize && textModeEnabled) {
        QChar CR = QLatin1Char('\r');
        QChar *writePtr = readBuffer.data() + oldReadBufferSize;
        QChar *readPtr = readBuffer.data() + oldReadBufferSize;
        QChar *endPtr = readBuffer.data() + readBuffer.size();

        int n = oldReadBufferSize;
        if (readPtr < endPtr) {
            // Cut-off to avoid unnecessary self-copying.
            while (*readPtr++ != CR) {
                ++n;
                if (++writePtr == endPtr)
                    break;
            }
        }
        while (readPtr < endPtr) {
            QChar ch = *readPtr++;
            if (ch != CR) {
                *writePtr++ = ch;
            } else {
                if (n < readBufferOffset)
                    --readBufferOffset;
                --bytesRead;
            }
            ++n;
        }
        readBuffer.resize(writePtr - readBuffer.data());
    }

#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStreamPrivate::fillReadBuffer() read %d bytes from device. readBuffer = [%s]", int(bytesRead),
           qt_prettyDebug(readBuffer.toLatin1(), readBuffer.size(), readBuffer.size()).data());
#endif
    return true;
}

/*! \internal
*/
bool QTextStreamPrivate::flushWriteBuffer()
{
    // no buffer next to the QString itself; this function should only
    // be called internally, for devices.
    if (string || !device)
        return false;
    if (writeBuffer.isEmpty())
        return true;

#if defined (Q_OS_WIN)
    // handle text translation and bypass the Text flag in the device.
    bool textModeEnabled = device->isTextModeEnabled();
    if (textModeEnabled) {
        device->setTextModeEnabled(false);
        writeBuffer.replace(QLatin1Char('\n'), QLatin1String("\r\n"));
    }
#endif

#ifndef QT_NO_TEXTCODEC
    if (!codec)
        codec = QTextCodec::codecForLocale();
#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStreamPrivate::flushWriteBuffer(), using %s codec (%s generating BOM)",
           codec->name().constData(), writeConverterState.flags & QTextCodec::IgnoreHeader ? "not" : "");
#endif

    // convert from unicode to raw data
    QByteArray data = codec->fromUnicode(writeBuffer.data(), writeBuffer.size(), &writeConverterState);
#else
    QByteArray data = writeBuffer.toLocal8Bit();
#endif
    writeBuffer.clear();

    // write raw data to the device
    qint64 bytesWritten = device->write(data);
#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStreamPrivate::flushWriteBuffer(), device->write(\"%s\") == %d",
           qt_prettyDebug(data.constData(), qMin(data.size(),32), data.size()).constData(), int(bytesWritten));
#endif
    if (bytesWritten <= 0)
        return false;

#if defined (Q_OS_WIN)
    // replace the text flag
    if (textModeEnabled)
        device->setTextModeEnabled(true);
#endif

    // flush the file
#ifndef QT_NO_QOBJECT
    QFile *file = qobject_cast<QFile *>(device);
    bool flushed = file && file->flush();
#else
    bool flushed = true;
#endif

#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStreamPrivate::flushWriteBuffer() wrote %d bytes",
           int(bytesWritten));
#endif
    return flushed && bytesWritten == qint64(data.size());
}

/*! \internal

    Scans no more than \a maxlen QChars in the current buffer for the
    first \a delimiter. Stores a pointer to the start offset of the
    token in \a ptr, and the length in QChars in \a length.
*/
bool QTextStreamPrivate::scan(const QChar **ptr, int *length, int maxlen, TokenDelimiter delimiter)
{
    int totalSize = 0;
    int delimSize = 0;
    bool consumeDelimiter = false;
    bool foundToken = false;
    int startOffset = device ? readBufferOffset : stringOffset;
    QChar lastChar;

    bool canStillReadFromDevice = true;
    do {
        int endOffset;
        const QChar *chPtr;
        if (device) {
            chPtr = readBuffer.constData();
            endOffset = readBuffer.size();
        } else {
            chPtr = string->constData();
            endOffset = string->size();
        }
        chPtr += startOffset;

        for (; !foundToken && startOffset < endOffset && (!maxlen || totalSize < maxlen); ++startOffset) {
            const QChar ch = *chPtr++;
            ++totalSize;

            if (delimiter == Space && ch.isSpace()) {
                foundToken = true;
                delimSize = 1;
            } else if (delimiter == NotSpace && !ch.isSpace()) {
                foundToken = true;
                delimSize = 1;
            } else if (delimiter == EndOfLine && ch == QLatin1Char('\n')) {
                foundToken = true;
                delimSize = (lastChar == QLatin1Char('\r')) ? 2 : 1;
                consumeDelimiter = true;
            }

            lastChar = ch;
        }
    } while (!foundToken
             && (!maxlen || totalSize < maxlen)
             && (device && (canStillReadFromDevice = fillReadBuffer())));

    // if the token was not found, but we reached the end of input,
    // then we accept what we got. if we are not at the end of input,
    // we return false.
    if (!foundToken && (!maxlen || totalSize < maxlen)
        && (totalSize == 0
            || (string && stringOffset + totalSize < string->size())
            || (device && !device->atEnd() && canStillReadFromDevice))) {
#if defined (QTEXTSTREAM_DEBUG)
        qDebug("QTextStreamPrivate::scan() did not find the token.");
#endif
        return false;
    }

    // if we find a '\r' at the end of the data when reading lines,
    // don't make it part of the line.
    if (totalSize > 0 && !foundToken && delimiter == EndOfLine) {
        if (((string && stringOffset + totalSize == string->size()) || (device && device->atEnd()))
            && lastChar == QLatin1Char('\r')) {
            consumeDelimiter = true;
            ++delimSize;
        }
    }

    // set the read offset and length of the token
    if (length)
        *length = totalSize - delimSize;
    if (ptr)
        *ptr = readPtr();

    // update last token size. the callee will call consumeLastToken() when
    // done.
    lastTokenSize = totalSize;
    if (!consumeDelimiter)
        lastTokenSize -= delimSize;

#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStreamPrivate::scan(%p, %p, %d, %x) token length = %d, delimiter = %d",
           ptr, length, maxlen, (int)delimiter, totalSize - delimSize, delimSize);
#endif
    return true;
}

/*! \internal
*/
inline const QChar *QTextStreamPrivate::readPtr() const
{
    Q_ASSERT(readBufferOffset <= readBuffer.size());
    if (string)
        return string->constData() + stringOffset;
    return readBuffer.constData() + readBufferOffset;
}

/*! \internal
*/
inline void QTextStreamPrivate::consumeLastToken()
{
    if (lastTokenSize)
        consume(lastTokenSize);
    lastTokenSize = 0;
}

/*! \internal
*/
inline void QTextStreamPrivate::consume(int size)
{
#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStreamPrivate::consume(%d)", size);
#endif
    if (string) {
        stringOffset += size;
        if (stringOffset > string->size())
            stringOffset = string->size();
    } else {
        readBufferOffset += size;
        if (readBufferOffset >= readBuffer.size()) {
            readBufferOffset = 0;
            readBuffer.clear();
            readBufferStartDevicePos = device->pos();
#ifndef QT_NO_TEXTCODEC
            copyConverterState(&readBufferStartReadConverterState, &readConverterState);
#endif
        }
    }
}

/*! \internal
*/
inline bool QTextStreamPrivate::write(const QString &data)
{
    if (string) {
        // ### What about seek()??
        string->append(data);
    } else {
        writeBuffer += data;
        if (writeBuffer.size() > QTEXTSTREAM_BUFFERSIZE)
            return flushWriteBuffer();
    }
    return true;
}

/*! \internal
*/
inline bool QTextStreamPrivate::getChar(QChar *ch)
{
    if ((string && stringOffset == string->size())
        || (device && readBuffer.isEmpty() && !fillReadBuffer())) {
        if (ch)
            *ch = 0;
        return false;
    }
    if (ch)
        *ch = *readPtr();
    consume(1);
    return true;
}

/*! \internal
*/
inline void QTextStreamPrivate::ungetChar(const QChar &ch)
{
    if (string) {
        if (stringOffset == 0)
            string->prepend(ch);
        else
            (*string)[--stringOffset] = ch;
        return;
    }

    if (readBufferOffset == 0) {
        readBuffer.prepend(ch);
        return;
    }

    readBuffer[--readBufferOffset] = ch;
}

/*! \internal
*/
inline bool QTextStreamPrivate::putString(const QString &s)
{
    QString tmp = s;

    // handle padding
    int padSize = fieldWidth - s.size();
    if (padSize > 0) {
        QString pad(padSize > 0 ? padSize : 0, padChar);
        if (fieldAlignment == QTextStream::AlignLeft) {
            tmp.append(QString(padSize, padChar));
        } else if (fieldAlignment == QTextStream::AlignRight) {
            tmp.prepend(QString(padSize, padChar));
        } else if (fieldAlignment == QTextStream::AlignCenter) {
            tmp.prepend(QString(padSize/2, padChar));
            tmp.append(QString(padSize - padSize/2, padChar));
        }
    }

#if defined (QTEXTSTREAM_DEBUG)
    QByteArray a = s.toUtf8();
    QByteArray b = tmp.toUtf8();
    qDebug("QTextStreamPrivate::putString(\"%s\") calls write(\"%s\")",
           qt_prettyDebug(a.constData(), a.size(), qMax(16, a.size())).constData(),
           qt_prettyDebug(b.constData(), b.size(), qMax(16, b.size())).constData());
#endif
    return write(tmp);
}

/*!
    Constructs a QTextStream. Before you can use it for reading or
    writing, you must assign a device or a string.

    \sa setDevice(), setString()
*/
QTextStream::QTextStream()
    : d_ptr(new QTextStreamPrivate(this))
{
#if defined (QTEXTSTREAM_DEBUG)
    qDebug("QTextStream::QTextStream()");