summaryrefslogtreecommitdiffstats
path: root/src/corelib/io/qdatastream.cpp
blob: 572b8a162db125fe70569cd5574ec06461d1998e (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
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
/****************************************************************************
**
** 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://qt.nokia.com/contact.
** $QT_END_LICENSE$
**
****************************************************************************/

#include "qdatastream.h"

#ifndef QT_NO_DATASTREAM
#include "qbuffer.h"
#include "qstring.h"
#include <stdio.h>
#include <ctype.h>
#include <stdlib.h>

QT_BEGIN_NAMESPACE

/*!
    \class QDataStream
    \reentrant
    \brief The QDataStream class provides serialization of binary data
    to a QIODevice.

    \ingroup io
    \mainclass

    A data stream is a binary stream of encoded information which is
    100% independent of the host computer's operating system, CPU or
    byte order. For example, a data stream that is written by a PC
    under Windows can be read by a Sun SPARC running Solaris.

    You can also use a data stream to read/write \l{raw}{raw
    unencoded binary data}. If you want a "parsing" input stream, see
    QTextStream.

    The QDataStream class implements the serialization of C++'s basic
    data types, like \c char, \c short, \c int, \c{char *}, etc.
    Serialization of more complex data is accomplished by breaking up
    the data into primitive units.

    A data stream cooperates closely with a QIODevice. A QIODevice
    represents an input/output medium one can read data from and write
    data to. The QFile class is an example of an I/O device.

    Example (write binary data to a stream):

    \snippet doc/src/snippets/code/src_corelib_io_qdatastream.cpp 0

    Example (read binary data from a stream):

    \snippet doc/src/snippets/code/src_corelib_io_qdatastream.cpp 1

    Each item written to the stream is written in a predefined binary
    format that varies depending on the item's type. Supported Qt
    types include QBrush, QColor, QDateTime, QFont, QPixmap, QString,
    QVariant and many others. For the complete list of all Qt types
    supporting data streaming see the \l{Format of the QDataStream
    operators}.

    For integers it is best to always cast to a Qt integer type for
    writing, and to read back into the same Qt integer type. This
    ensures that you get integers of the size you want and insulates
    you from compiler and platform differences.

    To take one example, a \c{char *} string is written as a 32-bit
    integer equal to the length of the string including the '\\0' byte,
    followed by all the characters of the string including the
    '\\0' byte. When reading a \c{char *} string, 4 bytes are read to
    create the 32-bit length value, then that many characters for the
    \c {char *} string including the '\\0' terminator are read.

    The initial I/O device is usually set in the constructor, but can be
    changed with setDevice(). If you've reached the end of the data
    (or if there is no I/O device set) atEnd() will return true.

    \section1 Versioning

    QDataStream's binary format has evolved since Qt 1.0, and is
    likely to continue evolving to reflect changes done in Qt. When
    inputting or outputting complex types, it's very important to
    make sure that the same version of the stream (version()) is used
    for reading and writing. If you need both forward and backward
    compatibility, you can hardcode the version number in the
    application:

    \snippet doc/src/snippets/code/src_corelib_io_qdatastream.cpp 2

    If you are producing a new binary data format, such as a file
    format for documents created by your application, you could use a
    QDataStream to write the data in a portable format. Typically, you
    would write a brief header containing a magic string and a version
    number to give yourself room for future expansion. For example:

    \snippet doc/src/snippets/code/src_corelib_io_qdatastream.cpp 3

    Then read it in with:

    \snippet doc/src/snippets/code/src_corelib_io_qdatastream.cpp 4

    You can select which byte order to use when serializing data. The
    default setting is big endian (MSB first). Changing it to little
    endian breaks the portability (unless the reader also changes to
    little endian). We recommend keeping this setting unless you have
    special requirements.

    \target raw
    \section1 Reading and writing raw binary data

    You may wish to read/write your own raw binary data to/from the
    data stream directly. Data may be read from the stream into a
    preallocated \c{char *} using readRawData(). Similarly data can be
    written to the stream using writeRawData(). Note that any
    encoding/decoding of the data must be done by you.

    A similar pair of functions is readBytes() and writeBytes(). These
    differ from their \e raw counterparts as follows: readBytes()
    reads a quint32 which is taken to be the length of the data to be
    read, then that number of bytes is read into the preallocated
    \c{char *}; writeBytes() writes a quint32 containing the length of the
    data, followed by the data. Note that any encoding/decoding of
    the data (apart from the length quint32) must be done by you.

    \target Serializing Qt Classes
    \section1 Reading and writing other Qt classes.

    In addition to the overloaded stream operators documented here,
    any Qt classes that you might want to serialize to a QDataStream
    will have appropriate stream operators declared as non-member of
    the class:

    \code
    QDataStream &operator<<(QDataStream &, const QXxx &);
    QDataStream &operator>>(QDataStream &, QXxx &);
    \endcode

    For example, here are the stream operators declared as non-members
    of the QImage class:

    \code
    QDataStream & operator<< (QDataStream& stream, const QImage& image);
    QDataStream & operator>> (QDataStream& stream, QImage& image);
    \endcode

    To see if your favorite Qt class has similar stream operators
    defined, check the \bold {Related Non-Members} section of the
    class's documentation page.

    \sa QTextStream QVariant
*/

/*!
    \enum QDataStream::ByteOrder

    The byte order used for reading/writing the data.

    \value BigEndian Most significant byte first (the default)
    \value LittleEndian Least significant byte first
*/

/*!
    \enum QDataStream::Status

    This enum describes the current status of the data stream.

    \value Ok               The data stream is operating normally.
    \value ReadPastEnd      The data stream has read past the end of the
                            data in the underlying device.
    \value ReadCorruptData  The data stream has read corrupt data.
*/

/*****************************************************************************
  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

enum {
    DefaultStreamVersion = QDataStream::Qt_4_5
};

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

/*!
    Constructs a data stream that has no I/O device.

    \sa setDevice()
*/

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

/*!
    Constructs a data stream that uses the I/O device \a d.

    \warning If you use QSocket or QSocketDevice as the I/O device \a d
    for reading data, you must make sure that enough data is available
    on the socket for the operation to successfully proceed;
    QDataStream does not have any means to handle or recover from
    short-reads.

    \sa setDevice(), device()
*/

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
/*!
    \fn QDataStream::QDataStream(QByteArray *array, int mode)
    \compat

    Constructs a data stream that operates on the given \a array. The
    \a mode specifies how the byte array is to be used, and is
    usually either QIODevice::ReadOnly or QIODevice::WriteOnly.
*/
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

/*!
    \fn QDataStream::QDataStream(QByteArray *a, QIODevice::OpenMode mode)

    Constructs a data stream that operates on a byte array, \a a. The
    \a mode describes how the device is to be used.

    Alternatively, you can use QDataStream(const QByteArray &) if you
    just want to read from a byte array.

    Since QByteArray is not a QIODevice subclass, internally a QBuffer
    is created to wrap the byte array.
*/

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;
}

/*!
    Constructs a read-only data stream that operates on byte array \a a.
    Use QDataStream(QByteArray*, int) if you want to write to a byte
    array.

    Since QByteArray is not a QIODevice subclass, internally a QBuffer
    is created to wrap the byte array.
*/
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;
}

/*!
    Destroys the data stream.

    The destructor will not affect the current I/O device, unless it is
    an internal I/O device (e.g. a QBuffer) processing a QByteArray
    passed in the \e constructor, in which case the internal I/O device
    is destroyed.
*/

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


/*!
    \fn QIODevice *QDataStream::device() const

    Returns the I/O device currently set, or 0 if no
    device is currently set.

    \sa setDevice()
*/

/*!
    void QDataStream::setDevice(QIODevice *d)

    Sets the I/O device to \a d, which can be 0
    to unset to current I/O device.

    \sa device()
*/

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

/*!
    \obsolete
    Unsets the I/O device.
    Use setDevice(0) instead.
*/

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


/*!
    \fn bool QDataStream::atEnd() const

    Returns true if the I/O device has reached the end position (end of
    the stream or file) or if there is no I/O device set; otherwise
    returns false.

    \sa QIODevice::atEnd()
*/

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

/*!
    Returns the status of the data stream.

    \sa Status setStatus() resetStatus()
*/

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

/*!
    Resets the status of the data stream.

    \sa Status status() setStatus()
*/
void QDataStream::resetStatus()
{
    q_status = Ok;
}

/*!
    Sets the status of the data stream to the \a status given.

    \sa Status status() resetStatus()
*/
void QDataStream::setStatus(Status status)
{
    if (q_status == Ok)
        q_status = status;
}

/*!\fn bool QDataStream::eof() const

    Use atEnd() instead.
*/

/*!
    \fn int QDataStream::byteOrder() const

    Returns the current byte order setting -- either BigEndian or
    LittleEndian.

    \sa setByteOrder()
*/

/*!
    Sets the serialization byte order to \a bo.

    The \a bo parameter can be QDataStream::BigEndian or
    QDataStream::LittleEndian.

    The default setting is big endian. We recommend leaving this
    setting unless you have special requirements.

    \sa byteOrder()
*/

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


/*!
    \fn bool QDataStream::isPrintableData() const

    In Qt 4, this function always returns false.

    \sa setPrintableData()
*/

/*!
    \fn void QDataStream::setPrintableData(bool enable)

    In Qt 3, this function enabled output in a human-readable
    format if \a enable was false.

    In Qt 4, QDataStream no longer provides a human-readable output.
    This function does nothing.
*/

/*!
    \enum QDataStream::Version

    This enum provides symbolic synonyms for the data serialization
    format version numbers.

    \value Qt_1_0 Version 1 (Qt 1.x)
    \value Qt_2_0 Version 2 (Qt 2.0)
    \value Qt_2_1 Version 3 (Qt 2.1, 2.2, 2.3)
    \value Qt_3_0 Version 4 (Qt 3.0)
    \value Qt_3_1 Version 5 (Qt 3.1, 3.2)
    \value Qt_3_3 Version 6 (Qt 3.3)
    \value Qt_4_0 Version 7 (Qt 4.0, Qt 4.1)
    \value Qt_4_1 Version 7 (Qt 4.0, Qt 4.1)
    \value Qt_4_2 Version 8 (Qt 4.2)
    \value Qt_4_3 Version 9 (Qt 4.3)
    \value Qt_4_4 Version 10 (Qt 4.4)
    \value Qt_4_5 Version 11 (Qt 4.5)
    \omitvalue Qt_4_6

    \sa setVersion(), version()
*/

/*!
    \fn int QDataStream::version() const

    Returns the version number of the data serialization format.

    \sa setVersion(), Version
*/

/*!
    \fn void QDataStream::setVersion(int v)

    Sets the version number of the data serialization format to \a v.

    You don't \e have to set a version if you are using the current
    version of Qt, but for your own custom binary formats we
    recommend that you do; see \l{Versioning} in the Detailed
    Description.

    In order to accommodate new functionality, the datastream
    serialization format of some Qt classes has changed in some
    versions of Qt. If you want to read data that was created by an
    earlier version of Qt, or write data that can be read by a
    program that was compiled with an earlier version of Qt, use this
    function to modify the serialization format used by QDataStream.

    \table
    \header \i Qt Version       \i QDataStream Version
    \row \i Qt 4.4                  \i 10
    \row \i Qt 4.3                  \i 9
    \row \i Qt 4.2                  \i 8
    \row \i Qt 4.0, 4.1            \i 7
    \row \i Qt 3.3                  \i 6
    \row \i Qt 3.1, 3.2             \i 5
    \row \i Qt 3.0                  \i 4
    \row \i Qt 2.1, 2.2, 2.3      \i 3
    \row \i Qt 2.0                  \i 2
    \row \i Qt 1.x                  \i 1
    \endtable

    The \l Version enum provides symbolic constants for the different
    versions of Qt. For example:

    \snippet doc/src/snippets/code/src_corelib_io_qdatastream.cpp 5

    \sa version(), Version
*/

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

/*!
    \fn QDataStream &QDataStream::operator>>(quint8 &i)
    \overload

    Reads an unsigned byte from the stream into \a i, and returns a
    reference to the stream.
*/

/*!
    Reads a signed byte from the stream into \a i, and returns a
    reference to the stream.
*/

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;
}


/*!
    \fn QDataStream &QDataStream::operator>>(quint16 &i)
    \overload

    Reads an unsigned 16-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

/*!
    \overload

    Reads a signed 16-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

QDataStream &QDataStream::operator>>(qint16 &i)
{
    i = 0;
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        if (dev->read((char *)&i, 2) != 2) {
            i = 0;
            setStatus(ReadPastEnd);
        }
    } else {
        union {
            qint16 val1;
            char val2[2];
        } x;
        char *p = x.val2;
        char b[2];
        if (dev->read(b, 2) == 2) {
            *p++ = b[1];
            *p = b[0];
            i = x.val1;
        } else {
            setStatus(ReadPastEnd);
        }
    }
    return *this;
}


/*!
    \fn QDataStream &QDataStream::operator>>(quint32 &i)
    \overload

    Reads an unsigned 32-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

/*!
    \overload

    Reads a signed 32-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

QDataStream &QDataStream::operator>>(qint32 &i)
{
    i = 0;
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        if (dev->read((char *)&i, 4) != 4) {
            i = 0;
            setStatus(ReadPastEnd);
        }
    } else {                                        // swap bytes
        union {
            qint32 val1;
            char val2[4];
        } x;
        char *p = x.val2;
        char b[4];
        if (dev->read(b, 4) == 4) {
            *p++ = b[3];
            *p++ = b[2];
            *p++ = b[1];
            *p   = b[0];
            i = x.val1;
        } else {
            setStatus(ReadPastEnd);
        }
    }
    return *this;
}

/*!
    \fn QDataStream &QDataStream::operator>>(quint64 &i)
    \overload

    Reads an unsigned 64-bit integer from the stream, into \a i, and
    returns a reference to the stream.
*/

/*!
    \overload

    Reads a signed 64-bit integer from the stream into \a i, and
    returns a reference to the stream.
*/

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 (noswap) {                        // no conversion needed
        if (dev->read((char *)&i, 8) != 8) {
            i = qint64(0);
            setStatus(ReadPastEnd);
        }
    } else {                                        // swap bytes
        union {
            qint64 val1;
            char val2[8];
        } x;

        char *p = x.val2;
        char b[8];
        if (dev->read(b, 8) == 8) {
            *p++ = b[7];
            *p++ = b[6];
            *p++ = b[5];
            *p++ = b[4];
            *p++ = b[3];
            *p++ = b[2];
            *p++ = b[1];
            *p   = b[0];
            i = x.val1;
        } else {
            setStatus(ReadPastEnd);
        }
    }
    return *this;
}

/*!
    Reads a boolean value from the stream into \a i. Returns a
    reference to the stream.
*/
QDataStream &QDataStream::operator>>(bool &i)
{
    qint8 v;
    *this >> v;
    i = !!v;
    return *this;
}

/*!
    \overload

    Reads a 32-bit floating point number from the stream into \a f,
    using the standard IEEE 754 format. Returns a reference to the
    stream.
*/

QDataStream &QDataStream::operator>>(float &f)
{
    f = 0.0f;
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        if (dev->read((char *)&f, 4) != 4) {
            f = 0.0f;
            setStatus(ReadPastEnd);
        }
    } else {                                        // swap bytes
        union {
            float val1;
            char val2[4];
        } x;

        char *p = x.val2;
        char b[4];
        if (dev->read(b, 4) == 4) {
            *p++ = b[3];
            *p++ = b[2];
            *p++ = b[1];
            *p = b[0];
            f = x.val1;
        } else {
            setStatus(ReadPastEnd);
        }
    }
    return *this;
}

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

/*!
    \overload

    Reads a 64-bit floating point number from the stream into \a f,
    using the standard IEEE 754 format. Returns a reference to the
    stream.
*/

QDataStream &QDataStream::operator>>(double &f)
{
    f = 0.0;
    CHECK_STREAM_PRECOND(*this)
#ifndef Q_DOUBLE_FORMAT
    if (noswap) {
        if (dev->read((char *)&f, 8) != 8) {
            f = 0.0;
            setStatus(ReadPastEnd);
        }
    } else {                                        // swap bytes
        union {
            double val1;
            char val2[8];
        } x;
        char *p = x.val2;
        char b[8];
        if (dev->read(b, 8) == 8) {
            *p++ = b[7];
            *p++ = b[6];
            *p++ = b[5];
            *p++ = b[4];
            *p++ = b[3];
            *p++ = b[2];
            *p++ = b[1];
            *p   = b[0];
            f = x.val1;
        } else {
            setStatus(ReadPastEnd);
        }
    }
#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;
}


/*!
    \overload

    Reads the '\0'-terminated string \a s from the stream and returns
    a reference to the stream.

    Space for the string is allocated using \c new -- the caller must
    destroy it with \c{delete[]}.
*/

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


/*!
    Reads the buffer \a s from the stream and returns a reference to
    the stream.

    The buffer \a s is allocated using \c new. Destroy it with the \c
    delete[] operator.

    The \a l parameter is set to the length of the buffer. If the
    string read is empty, \a l is set to 0 and \a s is set to
    a null pointer.

    The serialization format is a quint32 length specifier first,
    then \a l bytes of data.

    \sa readRawData(), writeBytes()
*/

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;
}

/*!
    Reads at most \a len bytes from the stream into \a s and returns the number of
    bytes read. If an error occurs, this function returns -1.

    The buffer \a s must be preallocated. The data is \e not encoded.

    \sa readBytes(), QIODevice::read(), writeRawData()
*/

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


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


/*!
    \fn QDataStream &QDataStream::operator<<(quint8 i)
    \overload

    Writes an unsigned byte, \a i, to the stream and returns a
    reference to the stream.
*/

/*!
    Writes a signed byte, \a i, to the stream and returns a reference
    to the stream.
*/

QDataStream &QDataStream::operator<<(qint8 i)
{
    CHECK_STREAM_PRECOND(*this)
    dev->putChar(i);
    return *this;
}


/*!
    \fn QDataStream &QDataStream::operator<<(quint16 i)
    \overload

    Writes an unsigned 16-bit integer, \a i, to the stream and returns
    a reference to the stream.
*/

/*!
    \overload

    Writes a signed 16-bit integer, \a i, to the stream and returns a
    reference to the stream.
*/

QDataStream &QDataStream::operator<<(qint16 i)
{
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        dev->write((char *)&i, sizeof(qint16));
    } else {                                        // swap bytes
        union {
            qint16 val1;
            char val2[2];
        } x;
        x.val1 = i;
        char *p = x.val2;
        char b[2];
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 2);
    }
    return *this;
}

/*!
    \overload

    Writes a signed 32-bit integer, \a i, to the stream and returns a
    reference to the stream.
*/

QDataStream &QDataStream::operator<<(qint32 i)
{
    CHECK_STREAM_PRECOND(*this)
    if (noswap) {
        dev->write((char *)&i, sizeof(qint32));
    } else {                                        // swap bytes
        union {
            qint32 val1;
            char val2[4];
        } x;
        x.val1 = i;
        char *p = x.val2;
        char b[4];
        b[3] = *p++;
        b[2] = *p++;
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 4);
    }
    return *this;
}

/*!
    \fn QDataStream &QDataStream::operator<<(quint64 i)
    \overload

    Writes an unsigned 64-bit integer, \a i, to the stream and returns a
    reference to the stream.
*/

/*!
    \overload

    Writes a signed 64-bit integer, \a i, to the stream and returns a
    reference to the stream.
*/

QDataStream &QDataStream::operator<<(qint64 i)
{
    CHECK_STREAM_PRECOND(*this)
    if (version() < 6) {
        quint32 i1 = i & 0xffffffff;
        quint32 i2 = i >> 32;
        *this << i2 << i1;
    } else if (noswap) {                        // no conversion needed
        dev->write((char *)&i, sizeof(qint64));
    } else {                                        // swap bytes
        union {
            qint64 val1;
            char val2[8];
        } x;
        x.val1 = i;
        char *p = x.val2;
        char b[8];
        b[7] = *p++;
        b[6] = *p++;
        b[5] = *p++;
        b[4] = *p++;
        b[3] = *p++;
        b[2] = *p++;
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 8);
    }
    return *this;
}

/*!
    \fn QDataStream &QDataStream::operator<<(quint32 i)
    \overload

    Writes an unsigned integer, \a i, to the stream as a 32-bit
    unsigned integer (quint32). Returns a reference to the stream.
*/

/*!
    Writes a boolean value, \a i, to the stream. Returns a reference
    to the stream.
*/

QDataStream &QDataStream::operator<<(bool i)
{
    CHECK_STREAM_PRECOND(*this)
    dev->putChar(qint8(i));
    return *this;
}

/*!
    \overload

    Writes a 32-bit floating point number, \a f, to the stream using
    the standard IEEE 754 format. Returns a reference to the stream.
*/

QDataStream &QDataStream::operator<<(float f)
{
    CHECK_STREAM_PRECOND(*this)
    float g = f;                                // fixes float-on-stack problem
    if (noswap) {                                // no conversion needed
        dev->write((char *)&g, sizeof(float));
    } else {                                // swap bytes
        union {
            float val1;
            char val2[4];
        } x;
        x.val1 = f;
        char *p = x.val2;
        char b[4];
        b[3] = *p++;
        b[2] = *p++;
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 4);
    }
    return *this;
}


/*!
    \overload

    Writes a 64-bit floating point number, \a f, to the stream using
    the standard IEEE 754 format. Returns a reference to the stream.
*/

QDataStream &QDataStream::operator<<(double f)
{
    CHECK_STREAM_PRECOND(*this)
#ifndef Q_DOUBLE_FORMAT
    if (noswap) {
        dev->write((char *)&f, sizeof(double));
    } else {
        union {
            double val1;
            char val2[8];
        } x;
        x.val1 = f;
        char *p = x.val2;
        char b[8];
        b[7] = *p++;
        b[6] = *p++;
        b[5] = *p++;
        b[4] = *p++;
        b[3] = *p++;
        b[2] = *p++;
        b[1] = *p++;
        b[0] = *p;
        dev->write(b, 8);
    }
#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;
    }
    dev->write(b, 8);
#endif
    return *this;
}


/*!
    \overload

    Writes the '\0'-terminated string \a s to the stream and returns a
    reference to the stream.

    The string is serialized using writeBytes().
*/

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;
}


/*!
    Writes the length specifier \a len and the buffer \a s to the
    stream and returns a reference to the stream.

    The \a len is serialized as a quint32, followed by \a len bytes
    from \a s. Note that the data is \e not encoded.

    \sa writeRawData(), readBytes()
*/

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


/*!
    Writes \a len bytes from \a s to the stream. Returns the
    number of bytes actually written, or -1 on error.
    The data is \e not encoded.

    \sa writeBytes(), QIODevice::write(), readRawData()
*/

int QDataStream::writeRawData(const char *s, int len)
{
    CHECK_STREAM_PRECOND(-1)
    return dev->write(s, len);
}

/*!
    \since 4.1

    Skips \a len bytes from the device. Returns the number of bytes
    actually skipped, or -1 on error.

    This is equivalent to calling readRawData() on a buffer of length
    \a len and ignoring the buffer.

    \sa QIODevice::seek()
*/
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
/*!
    \fn QDataStream &QDataStream::readRawBytes(char *str, uint len)

    Use readRawData() instead.
*/

/*!
    \fn QDataStream &QDataStream::writeRawBytes(const char *str, uint len)

    Use writeRawData() instead.
*/
#endif

QT_END_NAMESPACE

#endif // QT_NO_DATASTREAM