summaryrefslogtreecommitdiffstats
path: root/src/corelib/io/qbuffer.cpp
blob: 3883d30c9489499d665360035a75fb11b20c0735 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
/****************************************************************************
**
** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).
** Contact: Nokia Corporation (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 http://www.qtsoftware.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qbuffer.h"
#include "private/qiodevice_p.h"

QT_BEGIN_NAMESPACE

/** QBufferPrivate **/
class QBufferPrivate : public QIODevicePrivate
{
    Q_DECLARE_PUBLIC(QBuffer)

public:
    QBufferPrivate()
    : buf(0)
#ifndef QT_NO_QOBJECT
        , writtenSinceLastEmit(0), signalConnectionCount(0), signalsEmitted(false)
#endif
    { }
    ~QBufferPrivate() { }

    QByteArray *buf;
    QByteArray defaultBuf;
    int ioIndex;

#ifndef QT_NO_QOBJECT
    // private slots
    void _q_emitSignals();

    qint64 writtenSinceLastEmit;
    int signalConnectionCount;
    bool signalsEmitted;
#endif
};

#ifndef QT_NO_QOBJECT
void QBufferPrivate::_q_emitSignals()
{
    Q_Q(QBuffer);
    emit q->bytesWritten(writtenSinceLastEmit);
    writtenSinceLastEmit = 0;
    emit q->readyRead();
    signalsEmitted = false;
}
#endif

/*!
    \class QBuffer
    \reentrant
    \brief The QBuffer class provides a QIODevice interface for a QByteArray.

    \ingroup io

    QBuffer allows you to access a QByteArray using the QIODevice
    interface. The QByteArray is treated just as a standard random-accessed
    file. Example:

    \snippet doc/src/snippets/buffer/buffer.cpp 0

    By default, an internal QByteArray buffer is created for you when
    you create a QBuffer. You can access this buffer directly by
    calling buffer(). You can also use QBuffer with an existing
    QByteArray by calling setBuffer(), or by passing your array to
    QBuffer's constructor.

    Call open() to open the buffer. Then call write() or
    putChar() to write to the buffer, and read(), readLine(),
    readAll(), or getChar() to read from it. size() returns the
    current size of the buffer, and you can seek to arbitrary
    positions in the buffer by calling seek(). When you are done with
    accessing the buffer, call close().

    The following code snippet shows how to write data to a
    QByteArray using QDataStream and QBuffer:

    \snippet doc/src/snippets/buffer/buffer.cpp 1

    Effectively, we convert the application's QPalette into a byte
    array. Here's how to read the data from the QByteArray:

    \snippet doc/src/snippets/buffer/buffer.cpp 2

    QTextStream and QDataStream also provide convenience constructors
    that take a QByteArray and that create a QBuffer behind the
    scenes.

    QBuffer emits readyRead() when new data has arrived in the
    buffer. By connecting to this signal, you can use QBuffer to
    store temporary data before processing it. For example, you can
    pass the buffer to QFtp when downloading a file from an FTP
    server. Whenever a new payload of data has been downloaded,
    readyRead() is emitted, and you can process the data that just
    arrived. QBuffer also emits bytesWritten() every time new data
    has been written to the buffer.

    \sa QFile, QDataStream, QTextStream, QByteArray
*/

#ifdef QT_NO_QOBJECT
QBuffer::QBuffer()
    : QIODevice(*new QBufferPrivate)
{
    Q_D(QBuffer);
    d->buf = &d->defaultBuf;
    d->ioIndex = 0;
}
QBuffer::QBuffer(QByteArray *buf)
    : QIODevice(*new QBufferPrivate)
{
    Q_D(QBuffer);
    d->buf = buf ? buf : &d->defaultBuf;
    d->ioIndex = 0;
    d->defaultBuf.clear();
}
#else
/*!
    Constructs an empty buffer with the given \a parent. You can call
    setData() to fill the buffer with data, or you can open it in
    write mode and use write().

    \sa open()
*/
QBuffer::QBuffer(QObject *parent)
    : QIODevice(*new QBufferPrivate, parent)
{
    Q_D(QBuffer);
    d->buf = &d->defaultBuf;
    d->ioIndex = 0;
}

/*!
    Constructs a QBuffer that uses the QByteArray pointed to by \a
    byteArray as its internal buffer, and with the given \a parent.
    The caller is responsible for ensuring that \a byteArray remains
    valid until the QBuffer is destroyed, or until setBuffer() is
    called to change the buffer. QBuffer doesn't take ownership of
    the QByteArray.

    If you open the buffer in write-only mode or read-write mode and
    write something into the QBuffer, \a byteArray will be modified.

    Example:

    \snippet doc/src/snippets/buffer/buffer.cpp 3

    \sa open(), setBuffer(), setData()
*/
QBuffer::QBuffer(QByteArray *byteArray, QObject *parent)
    : QIODevice(*new QBufferPrivate, parent)
{
    Q_D(QBuffer);
    d->buf = byteArray ? byteArray : &d->defaultBuf;
    d->defaultBuf.clear();
    d->ioIndex = 0;
}
#endif

/*!
    Destroys the buffer.
*/

QBuffer::~QBuffer()
{
}

/*!
    Makes QBuffer uses the QByteArray pointed to by \a
    byteArray as its internal buffer. The caller is responsible for
    ensuring that \a byteArray remains valid until the QBuffer is
    destroyed, or until setBuffer() is called to change the buffer.
    QBuffer doesn't take ownership of the QByteArray.

    Does nothing if isOpen() is true.

    If you open the buffer in write-only mode or read-write mode and
    write something into the QBuffer, \a byteArray will be modified.

    Example:

    \snippet doc/src/snippets/buffer/buffer.cpp 4

    If \a byteArray is 0, the buffer creates its own internal
    QByteArray to work on. This byte array is initially empty.

    \sa buffer(), setData(), open()
*/

void QBuffer::setBuffer(QByteArray *byteArray)
{
    Q_D(QBuffer);
    if (isOpen()) {
        qWarning("QBuffer::setBuffer: Buffer is open");
        return;
    }
    if (byteArray) {
        d->buf = byteArray;
    } else {
        d->buf = &d->defaultBuf;
    }
    d->defaultBuf.clear();
    d->ioIndex = 0;
}

/*!
    Returns a reference to the QBuffer's internal buffer. You can use
    it to modify the QByteArray behind the QBuffer's back.

    \sa setBuffer(), data()
*/

QByteArray &QBuffer::buffer()
{
    Q_D(QBuffer);
    return *d->buf;
}

/*!
    \overload

    This is the same as data().
*/

const QByteArray &QBuffer::buffer() const
{
    Q_D(const QBuffer);
    return *d->buf;
}


/*!
    Returns the data contained in the buffer.

    This is the same as buffer().

    \sa setData(), setBuffer()
*/

const QByteArray &QBuffer::data() const
{
    Q_D(const QBuffer);
    return *d->buf;
}

/*!
    Sets the contents of the internal buffer to be \a data. This is
    the same as assigning \a data to buffer().

    Does nothing if isOpen() is true.

    \sa setBuffer()
*/
void QBuffer::setData(const QByteArray &data)
{
    Q_D(QBuffer);
    if (isOpen()) {
        qWarning("QBuffer::setData: Buffer is open");
        return;
    }
    *d->buf = data;
    d->ioIndex = 0;
}

/*!
    \fn void QBuffer::setData(const char *data, int size)

    \overload

    Sets the contents of the internal buffer to be the first \a size
    bytes of \a data.
*/

/*!
   \reimp
*/
bool QBuffer::open(OpenMode flags)
{
    Q_D(QBuffer);

    if ((flags & Append) == Append)
        flags |= WriteOnly;
    setOpenMode(flags);
    if (!(isReadable() || isWritable())) {
        qWarning("QFile::open: File access not specified");
        return false;
    }

    if ((flags & QIODevice::Truncate) == QIODevice::Truncate) {
        d->buf->resize(0);
    }
    if ((flags & QIODevice::Append) == QIODevice::Append) // append to end of buffer
        seek(d->buf->size());
    else
        seek(0);

    return true;
}

/*!
    \reimp
*/
void QBuffer::close()
{
    QIODevice::close();
}

/*!
    \reimp
*/
qint64 QBuffer::pos() const
{
    return QIODevice::pos();
}

/*!
    \reimp
*/
qint64 QBuffer::size() const
{
    Q_D(const QBuffer);
    return qint64(d->buf->size());
}

/*!
    \reimp
*/
bool QBuffer::seek(qint64 pos)
{
    Q_D(QBuffer);
    if (pos > d->buf->size() && isWritable()) {
        if (seek(d->buf->size())) {
            const qint64 gapSize = pos - d->buf->size();
            if (write(QByteArray(gapSize, 0)) != gapSize) {
                qWarning("QBuffer::seek: Unable to fill gap");
                return false;
            }
        } else {
            return false;
        }
    } else if (pos > d->buf->size() || pos < 0) {
        qWarning("QBuffer::seek: Invalid pos: %d", int(pos));
        return false;
    }
    d->ioIndex = int(pos);
    return QIODevice::seek(pos);
}

/*!
    \reimp
*/
bool QBuffer::atEnd() const
{
    return QIODevice::atEnd();
}

/*!
   \reimp
*/
bool QBuffer::canReadLine() const
{
    Q_D(const QBuffer);
    if (!isOpen())
        return false;

    return d->buf->indexOf('\n', int(pos())) != -1 || QIODevice::canReadLine();
}

/*!
    \reimp
*/
qint64 QBuffer::readData(char *data, qint64 len)
{
    Q_D(QBuffer);
    if ((len = qMin(len, qint64(d->buf->size()) - d->ioIndex)) <= 0)
        return qint64(0);
    memcpy(data, d->buf->constData() + d->ioIndex, len);
    d->ioIndex += int(len);
    return len;
}

/*!
    \reimp
*/
qint64 QBuffer::writeData(const char *data, qint64 len)
{
    Q_D(QBuffer);
    int extraBytes = d->ioIndex + len - d->buf->size();
    if (extraBytes > 0) { // overflow
        int newSize = d->buf->size() + extraBytes;
        d->buf->resize(newSize);
        if (d->buf->size() != newSize) { // could not resize
            qWarning("QBuffer::writeData: Memory allocation error");
            return -1;
        }
    }

    memcpy(d->buf->data() + d->ioIndex, (uchar *)data, int(len));
    d->ioIndex += int(len);

#ifndef QT_NO_QOBJECT
    d->writtenSinceLastEmit += len;
    if (d->signalConnectionCount && !d->signalsEmitted && !signalsBlocked()) {
        d->signalsEmitted = true;
        QMetaObject::invokeMethod(this, "_q_emitSignals", Qt::QueuedConnection);
    }
#endif
    return len;
}

#ifndef QT_NO_QOBJECT
/*!
    \reimp
    \internal
*/
void QBuffer::connectNotify(const char *signal)
{
    if (strcmp(signal + 1, "readyRead()") == 0 || strcmp(signal + 1, "bytesWritten(qint64)") == 0)
        d_func()->signalConnectionCount++;
}

/*!
    \reimp
    \internal
*/
void QBuffer::disconnectNotify(const char *signal)
{
    if (!signal || strcmp(signal + 1, "readyRead()") == 0 || strcmp(signal + 1, "bytesWritten(qint64)") == 0)
        d_func()->signalConnectionCount--;
}
#endif

QT_END_NAMESPACE

#ifndef QT_NO_QOBJECT
# include "moc_qbuffer.cpp"
#endif