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Diffstat (limited to 'src/corelib/io/qnoncontiguousbytedevice.cpp')
| -rw-r--r-- | src/corelib/io/qnoncontiguousbytedevice.cpp | 542 |
1 files changed, 542 insertions, 0 deletions
diff --git a/src/corelib/io/qnoncontiguousbytedevice.cpp b/src/corelib/io/qnoncontiguousbytedevice.cpp new file mode 100644 index 0000000..6233fde --- /dev/null +++ b/src/corelib/io/qnoncontiguousbytedevice.cpp @@ -0,0 +1,542 @@ +/**************************************************************************** +** +** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies). +** Contact: Qt Software Information (qt-info@nokia.com) +** +** This file is part of the QtCore module of the Qt Toolkit. +** +** $QT_BEGIN_LICENSE:LGPL$ +** No Commercial Usage +** This file contains pre-release code and may not be distributed. +** You may use this file in accordance with the terms and conditions +** contained in the either Technology Preview License Agreement or the +** Beta Release License Agreement. +** +** GNU Lesser General Public License Usage +** Alternatively, this file may be used under the terms of the GNU Lesser +** General Public License version 2.1 as published by the Free Software +** Foundation and appearing in the file LICENSE.LGPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU Lesser General Public License version 2.1 requirements +** will be met: http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html. +** +** In addition, as a special exception, Nokia gives you certain +** additional rights. These rights are described in the Nokia Qt LGPL +** Exception version 1.0, included in the file LGPL_EXCEPTION.txt in this +** package. +** +** GNU General Public License Usage +** Alternatively, this file may be used under the terms of the GNU +** General Public License version 3.0 as published by the Free Software +** Foundation and appearing in the file LICENSE.GPL included in the +** packaging of this file. Please review the following information to +** ensure the GNU General Public License version 3.0 requirements will be +** met: http://www.gnu.org/copyleft/gpl.html. +** +** If you are unsure which license is appropriate for your use, please +** contact the sales department at qt-sales@nokia.com. +** $QT_END_LICENSE$ +** +****************************************************************************/ + +#include "qnoncontiguousbytedevice_p.h" +#include <QObject> +#include <QBuffer> +#include <QDebug> +#include <QFile> + +QT_BEGIN_NAMESPACE + +/*! + \class QNonContiguousByteDevice + \brief A QNonContiguousByteDevice is a representation of a + file, array or buffer that allows access with a read pointer. + \since 4.6 + + \inmodule QtCore + + The goal of this class is to have a data representation that + allows us to avoid doing a memcpy as we have to do with QIODevice. + + \sa QNonContiguousByteDeviceFactory + + \internal +*/ +/*! + \fn virtual const char* QNonContiguousByteDevice::readPointer(qint64 maximumLength, qint64 &len) + + Return a byte pointer for at most \a maximumLength bytes of that device. + if \a maximumLength is -1, the caller does not care about the length and + the device may return what it desires to. + The actual number of bytes the pointer is valid for is returned in + the \a len variable. + \a len will be -1 if EOF or an error occurs. + If it was really EOF can then afterwards be checked with atEnd() + Returns 0 if it is not possible to read at that position. + + \sa atEnd() + + \internal +*/ +/*! + \fn virtual bool QNonContiguousByteDevice::advanceReadPointer(qint64 amount) + + will advance the internal read pointer by \a amount bytes. + The old readPointer is invalid after this call. + + \sa readPointer() + + \internal +*/ +/*! + \fn virtual bool QNonContiguousByteDevice::atEnd() + + Returns true if everything has been read and the read + pointer cannot be advanced anymore. + + \sa readPointer(), advanceReadPointer(), reset() + + \internal +*/ +/*! + \fn virtual bool QNonContiguousByteDevice::reset() + + Moves the internal read pointer back to the beginning. + Returns false if this was not possible. + + \sa atEnd(), disableReset() + + \internal +*/ +/*! + \fn void QNonContiguousByteDevice::disableReset() + + Disable the reset() call, e.g. it will always + do nothing and return false. + + \sa reset() + + \internal +*/ +/*! + \fn virtual qint64 QNonContiguousByteDevice::size() + + Returns the size of the complete device or -1 if unknown. + May also return less/more than what can be actually read with readPointer() + + \internal +*/ +/*! + \fn void QNonContiguousByteDevice::readyRead() + + Emitted when there is data available + + \internal +*/ +/*! + \fn void QNonContiguousByteDevice::readProgress(qint64 current, qint64 total) + + Emitted when data has been "read" by advancing the read pointer + + \internal +*/ + +QNonContiguousByteDevice::QNonContiguousByteDevice() : QObject((QObject*)0), resetDisabled(false) +{ +}; + +QNonContiguousByteDevice::~QNonContiguousByteDevice() +{ +}; + +void QNonContiguousByteDevice::disableReset() +{ + resetDisabled = true; +} + +QNonContiguousByteDeviceBufferImpl::QNonContiguousByteDeviceBufferImpl(QBuffer *b) : QNonContiguousByteDevice() +{ + buffer = b; + byteArray = QByteArray::fromRawData(buffer->buffer().constData() + buffer->pos(), buffer->size() - buffer->pos()); + arrayImpl = new QNonContiguousByteDeviceByteArrayImpl(&byteArray); + arrayImpl->setParent(this); + connect(arrayImpl, SIGNAL(readyRead()), SIGNAL(readyRead())); + connect(arrayImpl, SIGNAL(readProgress(qint64,qint64)), SIGNAL(readProgress(qint64,qint64))); +} + +QNonContiguousByteDeviceBufferImpl::~QNonContiguousByteDeviceBufferImpl() +{ +} + +const char* QNonContiguousByteDeviceBufferImpl::readPointer(qint64 maximumLength, qint64 &len) +{ + return arrayImpl->readPointer(maximumLength, len); +} + +bool QNonContiguousByteDeviceBufferImpl::advanceReadPointer(qint64 amount) +{ + return arrayImpl->advanceReadPointer(amount); +} + +bool QNonContiguousByteDeviceBufferImpl::atEnd() +{ + return arrayImpl->atEnd(); +} + +bool QNonContiguousByteDeviceBufferImpl::reset() +{ + if (resetDisabled) + return false; + return arrayImpl->reset(); +} + +qint64 QNonContiguousByteDeviceBufferImpl::size() +{ + return arrayImpl->size(); +} + +QNonContiguousByteDeviceByteArrayImpl::QNonContiguousByteDeviceByteArrayImpl(QByteArray *ba) : QNonContiguousByteDevice(), currentPosition(0) +{ + byteArray = ba; +} + +QNonContiguousByteDeviceByteArrayImpl::~QNonContiguousByteDeviceByteArrayImpl() +{ +} + +const char* QNonContiguousByteDeviceByteArrayImpl::readPointer(qint64 maximumLength, qint64 &len) +{ + if (atEnd()) { + len = -1; + return 0; + } + + if (maximumLength != -1) + len = qMin(maximumLength, size() - currentPosition); + else + len = size() - currentPosition; + + return byteArray->constData() + currentPosition; +} + +bool QNonContiguousByteDeviceByteArrayImpl::advanceReadPointer(qint64 amount) +{ + currentPosition += amount; + emit readProgress(currentPosition, size()); + return true; +} + +bool QNonContiguousByteDeviceByteArrayImpl::atEnd() +{ + return currentPosition >= size(); +} + +bool QNonContiguousByteDeviceByteArrayImpl::reset() +{ + if (resetDisabled) + return false; + + currentPosition = 0; + return true; +} + +qint64 QNonContiguousByteDeviceByteArrayImpl::size() +{ + return byteArray->size(); +} + +QNonContiguousByteDeviceRingBufferImpl::QNonContiguousByteDeviceRingBufferImpl(QRingBuffer *rb) + : QNonContiguousByteDevice(), currentPosition(0) +{ + ringBuffer = rb; +} + +QNonContiguousByteDeviceRingBufferImpl::~QNonContiguousByteDeviceRingBufferImpl() +{ +}; + +const char* QNonContiguousByteDeviceRingBufferImpl::readPointer(qint64 maximumLength, qint64 &len) +{ + if (atEnd()) { + len = -1; + return 0; + } + + const char *returnValue = ringBuffer->readPointerAtPosition(currentPosition, len); + + if (maximumLength != -1) + len = qMin(len, maximumLength); + + return returnValue; +}; + +bool QNonContiguousByteDeviceRingBufferImpl::advanceReadPointer(qint64 amount) +{ + currentPosition += amount; + emit readProgress(currentPosition, size()); + return true; +}; + +bool QNonContiguousByteDeviceRingBufferImpl::atEnd() +{ + return currentPosition >= size(); +}; + +bool QNonContiguousByteDeviceRingBufferImpl::reset() +{ + if (resetDisabled) + return false; + + currentPosition = 0; + return true; +}; + +qint64 QNonContiguousByteDeviceRingBufferImpl::size() +{ + return ringBuffer->size(); +}; + +QNonContiguousByteDeviceIoDeviceImpl::QNonContiguousByteDeviceIoDeviceImpl(QIODevice *d) + : QNonContiguousByteDevice(), + currentReadBuffer(0), currentReadBufferSize(16*1024), + currentReadBufferAmount(0), currentReadBufferPosition(0), totalAdvancements(0), + eof(false) +{ + device = d; + initialPosition = d->pos(); + connect(device, SIGNAL(readyRead()), this, SIGNAL(readyRead()), Qt::QueuedConnection); + connect(device, SIGNAL(readChannelFinished()), this, SIGNAL(readyRead()), Qt::QueuedConnection); +}; + +QNonContiguousByteDeviceIoDeviceImpl::~QNonContiguousByteDeviceIoDeviceImpl() +{ + delete currentReadBuffer; +}; + +const char* QNonContiguousByteDeviceIoDeviceImpl::readPointer(qint64 maximumLength, qint64 &len) +{ + if (eof == true) { + len = -1; + return 0; + } + + if (currentReadBuffer == 0) + currentReadBuffer = new QByteArray(currentReadBufferSize, '\0'); // lazy alloc + + if (maximumLength == -1) + maximumLength = currentReadBufferSize; + + if (currentReadBufferAmount - currentReadBufferPosition > 0) { + len = currentReadBufferAmount - currentReadBufferPosition; + return currentReadBuffer->data() + currentReadBufferPosition; + } + + qint64 haveRead = device->read(currentReadBuffer->data(), qMin(maximumLength, currentReadBufferSize)); + + if ((haveRead == -1) || (haveRead == 0 && device->atEnd() && !device->isSequential())) { + eof = true; + len = -1; + // size was unknown before, emit a readProgress with the final size + if (size() == -1) + emit readProgress(totalAdvancements, totalAdvancements); + return 0; + } + + currentReadBufferAmount = haveRead; + currentReadBufferPosition = 0; + + len = haveRead; + return currentReadBuffer->data(); +}; + +bool QNonContiguousByteDeviceIoDeviceImpl::advanceReadPointer(qint64 amount) +{ + totalAdvancements += amount; + + // normal advancement + currentReadBufferPosition += amount; + + // advancing over that what has actually been read before + if (currentReadBufferPosition > currentReadBufferAmount) { + qint64 i = currentReadBufferPosition - currentReadBufferAmount; + while (i > 0) { + if (device->getChar(0) == false) { + emit readProgress(totalAdvancements - i, size()); + return false; // ### FIXME handle eof + } + i--; + } + + currentReadBufferPosition = 0; + currentReadBufferAmount = 0; + } + + if (size() == -1) + emit readProgress(totalAdvancements, totalAdvancements); + else + emit readProgress(totalAdvancements, size()); + + return true; +}; + +bool QNonContiguousByteDeviceIoDeviceImpl::atEnd() +{ + return eof == true; +}; + +bool QNonContiguousByteDeviceIoDeviceImpl::reset() +{ + if (resetDisabled) + return false; + + if (device->seek(initialPosition)) { + eof = false; // assume eof is false, it will be true after a read has been attempted + return true; + } + + return false; +}; + +qint64 QNonContiguousByteDeviceIoDeviceImpl::size() +{ + // note that this is different from the size() implementation of QIODevice! + + if (device->isSequential()) + return -1; + + return device->size() - initialPosition; +}; + +QByteDeviceWrappingIoDevice::QByteDeviceWrappingIoDevice(QNonContiguousByteDevice *bd) : QIODevice((QObject*)0) +{ + byteDevice = bd; + connect(bd, SIGNAL(readyRead()), SIGNAL(readyRead())); + + open(ReadOnly); +} + +QByteDeviceWrappingIoDevice::~QByteDeviceWrappingIoDevice() +{ + +} + +bool QByteDeviceWrappingIoDevice::isSequential() const +{ + return (byteDevice->size() == -1); +} + +bool QByteDeviceWrappingIoDevice::atEnd() const +{ + return byteDevice->atEnd(); +} + +bool QByteDeviceWrappingIoDevice::reset() +{ + return byteDevice->reset(); +} + +qint64 QByteDeviceWrappingIoDevice::size() const +{ + if (isSequential()) + return 0; + + return byteDevice->size(); +} + + +qint64 QByteDeviceWrappingIoDevice::readData( char * data, qint64 maxSize) +{ + qint64 len; + const char *readPointer = byteDevice->readPointer(maxSize, len); + if (len == -1) + return -1; + + memcpy(data, readPointer, len); + byteDevice->advanceReadPointer(len); + return len; +} + +qint64 QByteDeviceWrappingIoDevice::writeData( const char* data, qint64 maxSize) +{ + return -1; +} + +/*! + \class QNonContiguousByteDeviceFactory + \since 4.6 + + \inmodule QtCore + + Creates a QNonContiguousByteDevice out of a QIODevice, + QByteArray etc. + + \sa QNonContiguousByteDevice + + \internal +*/ + +/*! + \fn static QNonContiguousByteDevice* QNonContiguousByteDeviceFactory::create(QIODevice *device); + + Create a QNonContiguousByteDevice out of a QIODevice. + For QFile, QBuffer and all other QIoDevice, sequential or not. + + \internal +*/ +QNonContiguousByteDevice* QNonContiguousByteDeviceFactory::create(QIODevice *device) +{ + // shortcut if it is a QBuffer + if (QBuffer* buffer = qobject_cast<QBuffer*>(device)) { + return new QNonContiguousByteDeviceBufferImpl(buffer); + } + + // ### FIXME special case if device is a QFile that supports map() + // then we can actually deal with the file without using read/peek + + // generic QIODevice + return new QNonContiguousByteDeviceIoDeviceImpl(device); // FIXME +}; + +/*! + \fn static QNonContiguousByteDevice* QNonContiguousByteDeviceFactory::create(QRingBuffer *ringBuffer); + + Create a QNonContiguousByteDevice out of a QRingBuffer. + + \internal +*/ +QNonContiguousByteDevice* QNonContiguousByteDeviceFactory::create(QRingBuffer *ringBuffer) +{ + return new QNonContiguousByteDeviceRingBufferImpl(ringBuffer); +}; + +/*! + \fn static QNonContiguousByteDevice* QNonContiguousByteDeviceFactory::create(QByteArray *byteArray); + + Create a QNonContiguousByteDevice out of a QByteArray. + + \internal +*/ +QNonContiguousByteDevice* QNonContiguousByteDeviceFactory::create(QByteArray *byteArray) +{ + return new QNonContiguousByteDeviceByteArrayImpl(byteArray); +}; + +/*! + \fn static QIODevice* QNonContiguousByteDeviceFactory::wrap(QNonContiguousByteDevice* byteDevice); + + Wrap the \a byteDevice (possibly again) into a QIODevice. + + \internal +*/ +QIODevice* QNonContiguousByteDeviceFactory::wrap(QNonContiguousByteDevice* byteDevice) +{ + // ### FIXME if it already has been based on QIoDevice, we could that one out again + // and save some calling + + // needed for FTP backend + + return new QByteDeviceWrappingIoDevice(byteDevice); +} + +QT_END_NAMESPACE + |