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| author | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
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| committer | Timothy Pearson <kb9vqf@pearsoncomputing.net> | 2011-07-10 15:24:15 -0500 |
| commit | bd0f3345a938b35ce6a12f6150373b0955b8dd12 (patch) | |
| tree | 7a520322212d48ebcb9fbe1087e7fca28b76185c /doc/html/qdatastream.html | |
| download | qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.tar.gz qt3-bd0f3345a938b35ce6a12f6150373b0955b8dd12.zip | |
Add Qt3 development HEAD version
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| -rw-r--r-- | doc/html/qdatastream.html | 570 |
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diff --git a/doc/html/qdatastream.html b/doc/html/qdatastream.html new file mode 100644 index 0000000..3e9e9ce --- /dev/null +++ b/doc/html/qdatastream.html @@ -0,0 +1,570 @@ +<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN"> +<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/src/tools/qdatastream.cpp:51 --> +<html> +<head> +<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> +<title>QDataStream Class</title> +<style type="text/css"><!-- +fn { margin-left: 1cm; text-indent: -1cm; } +a:link { color: #004faf; text-decoration: none } +a:visited { color: #672967; text-decoration: none } +body { background: #ffffff; color: black; } +--></style> +</head> +<body> + +<table border="0" cellpadding="0" cellspacing="0" width="100%"> +<tr bgcolor="#E5E5E5"> +<td valign=center> + <a href="index.html"> +<font color="#004faf">Home</font></a> + | <a href="classes.html"> +<font color="#004faf">All Classes</font></a> + | <a href="mainclasses.html"> +<font color="#004faf">Main Classes</font></a> + | <a href="annotated.html"> +<font color="#004faf">Annotated</font></a> + | <a href="groups.html"> +<font color="#004faf">Grouped Classes</font></a> + | <a href="functions.html"> +<font color="#004faf">Functions</font></a> +</td> +<td align="right" valign="center"><img src="logo32.png" align="right" width="64" height="32" border="0"></td></tr></table><h1 align=center>QDataStream Class Reference</h1> + +<p>The QDataStream class provides serialization of binary data +to a QIODevice. +<a href="#details">More...</a> +<p>All the functions in this class are <a href="threads.html#reentrant">reentrant</a> when Qt is built with thread support.</p> +<p><tt>#include <<a href="qdatastream-h.html">qdatastream.h</a>></tt> +<p><a href="qdatastream-members.html">List of all member functions.</a> +<h2>Public Members</h2> +<ul> +<li class=fn><a href="#QDataStream"><b>QDataStream</b></a> ()</li> +<li class=fn><a href="#QDataStream-2"><b>QDataStream</b></a> ( QIODevice * d )</li> +<li class=fn><a href="#QDataStream-3"><b>QDataStream</b></a> ( QByteArray a, int mode )</li> +<li class=fn>virtual <a href="#~QDataStream"><b>~QDataStream</b></a> ()</li> +<li class=fn>QIODevice * <a href="#device"><b>device</b></a> () const</li> +<li class=fn>void <a href="#setDevice"><b>setDevice</b></a> ( QIODevice * d )</li> +<li class=fn>void <a href="#unsetDevice"><b>unsetDevice</b></a> ()</li> +<li class=fn>bool <a href="#atEnd"><b>atEnd</b></a> () const</li> +<li class=fn>bool eof () const <em>(obsolete)</em></li> +<li class=fn>enum <a href="#ByteOrder-enum"><b>ByteOrder</b></a> { BigEndian, LittleEndian }</li> +<li class=fn>int <a href="#byteOrder"><b>byteOrder</b></a> () const</li> +<li class=fn>void <a href="#setByteOrder"><b>setByteOrder</b></a> ( int bo )</li> +<li class=fn>bool <a href="#isPrintableData"><b>isPrintableData</b></a> () const</li> +<li class=fn>void <a href="#setPrintableData"><b>setPrintableData</b></a> ( bool enable )</li> +<li class=fn>int <a href="#version"><b>version</b></a> () const</li> +<li class=fn>void <a href="#setVersion"><b>setVersion</b></a> ( int v )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt"><b>operator>></b></a> ( Q_INT8 & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-2"><b>operator>></b></a> ( Q_UINT8 & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-3"><b>operator>></b></a> ( Q_INT16 & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-4"><b>operator>></b></a> ( Q_UINT16 & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-5"><b>operator>></b></a> ( Q_INT32 & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-6"><b>operator>></b></a> ( Q_UINT32 & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-7"><b>operator>></b></a> ( Q_INT64 & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-8"><b>operator>></b></a> ( Q_UINT64 & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-9"><b>operator>></b></a> ( Q_LONG & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-a"><b>operator>></b></a> ( Q_ULONG & i )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-b"><b>operator>></b></a> ( float & f )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-c"><b>operator>></b></a> ( double & f )</li> +<li class=fn>QDataStream & <a href="#operator-gt-gt-d"><b>operator>></b></a> ( char *& s )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt"><b>operator<<</b></a> ( Q_INT8 i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-2"><b>operator<<</b></a> ( Q_UINT8 i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-3"><b>operator<<</b></a> ( Q_INT16 i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-4"><b>operator<<</b></a> ( Q_UINT16 i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-5"><b>operator<<</b></a> ( Q_INT32 i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-6"><b>operator<<</b></a> ( Q_UINT32 i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-7"><b>operator<<</b></a> ( Q_INT64 i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-8"><b>operator<<</b></a> ( Q_UINT64 i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-9"><b>operator<<</b></a> ( Q_LONG i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-a"><b>operator<<</b></a> ( Q_ULONG i )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-b"><b>operator<<</b></a> ( float f )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-c"><b>operator<<</b></a> ( double f )</li> +<li class=fn>QDataStream & <a href="#operator-lt-lt-d"><b>operator<<</b></a> ( const char * s )</li> +<li class=fn>QDataStream & <a href="#readBytes"><b>readBytes</b></a> ( char *& s, uint & l )</li> +<li class=fn>QDataStream & <a href="#readRawBytes"><b>readRawBytes</b></a> ( char * s, uint len )</li> +<li class=fn>QDataStream & <a href="#writeBytes"><b>writeBytes</b></a> ( const char * s, uint len )</li> +<li class=fn>QDataStream & <a href="#writeRawBytes"><b>writeRawBytes</b></a> ( const char * s, uint len )</li> +</ul> +<hr><a name="details"></a><h2>Detailed Description</h2> + + + +The QDataStream class provides serialization of binary data +to a <a href="qiodevice.html">QIODevice</a>. +<p> +<p> 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. +<p> You can also use a data stream to read/write <a href="#raw">raw + unencoded binary data</a>. If you want a "parsing" input +stream, see <a href="qtextstream.html">QTextStream</a>. +<p> The QDataStream class implements the serialization of C++'s basic +data types, like <tt>char</tt>, <tt>short</tt>, <tt>int</tt>, <tt>char*</tt>, etc. +Serialization of more complex data is accomplished by breaking up +the data into primitive units. +<p> 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 <a href="qfile.html">QFile</a> class is an example of an IO device. +<p> Example (write binary data to a stream): +<pre> + <a href="qfile.html">QFile</a> file( "file.dat" ); + file.<a href="qfile.html#open">open</a>( <a href="qfile.html#open">IO_WriteOnly</a> ); + QDataStream stream( &file ); // we will serialize the data into the file + stream << "the answer is"; // serialize a string + stream << (Q_INT32)42; // serialize an integer + </pre> + +<p> Example (read binary data from a stream): +<pre> + <a href="qfile.html">QFile</a> file( "file.dat" ); + file.<a href="qfile.html#open">open</a>( <a href="qfile.html#open">IO_ReadOnly</a> ); + QDataStream stream( &file ); // read the data serialized from the file + <a href="qstring.html">QString</a> str; + Q_INT32 a; + stream >> str >> a; // extract "the answer is" and 42 + </pre> + +<p> 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 <a href="qbrush.html">QBrush</a>, <a href="qcolor.html">QColor</a>, <a href="qdatetime.html">QDateTime</a>, <a href="qfont.html">QFont</a>, <a href="qpixmap.html">QPixmap</a>, <a href="qstring.html">QString</a>, +<a href="qvariant.html">QVariant</a> and many others. For the complete list of all Qt types +supporting data streaming see the <a href="datastreamformat.html">Format of the QDataStream operators</a>. +<p> 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. +<p> To take one example, a <tt>char*</tt> string is written as a 32-bit +integer equal to the length of the string including the NUL byte +('\0'), followed by all the characters of the string including the +NUL byte. When reading a <tt>char*</tt> string, 4 bytes are read to +create the 32-bit length value, then that many characters for the +<tt>char*</tt> string including the NUL are read. +<p> The initial IODevice is usually set in the constructor, but can be +changed with <a href="#setDevice">setDevice</a>(). If you've reached the end of the data +(or if there is no IODevice set) <a href="#atEnd">atEnd</a>() will return TRUE. +<p> If you want the data to be compatible with an earlier version of +Qt use <a href="#setVersion">setVersion</a>(). +<p> If you want the data to be human-readable, e.g. for debugging, you +can set the data stream into printable data mode with +<a href="#setPrintableData">setPrintableData</a>(). The data is then written slower, in a bloated +but human readable format. +<p> 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: +<p> <pre> + <a href="qfile.html">QFile</a> file( "file.xxx" ); + file.<a href="qfile.html#open">open</a>( IO_WriteOnly ); + QDataStream stream( &file ); + + // Write a header with a "magic number" and a version + stream << (Q_UINT32)0xA0B0C0D0; + stream << (Q_INT32)123; + + // Write the data + stream << [lots of interesting data] + </pre> + +<p> Then read it in with: +<p> <pre> + <a href="qfile.html">QFile</a> file( "file.xxx" ); + file.<a href="qfile.html#open">open</a>( IO_ReadOnly ); + QDataStream stream( &file ); + + // Read and check the header + Q_UINT32 magic; + stream >> magic; + if ( magic != 0xA0B0C0D0 ) + return XXX_BAD_FILE_FORMAT; + + // Read the version + Q_INT32 version; + stream >> version; + if ( version < 100 ) + return XXX_BAD_FILE_TOO_OLD; + if ( version > 123 ) + return XXX_BAD_FILE_TOO_NEW; + if ( version <= 110 ) + stream.<a href="#setVersion">setVersion</a>(1); + + // Read the data + stream >> [lots of interesting data]; + if ( version > 120 ) + stream >> [data new in XXX version 1.2]; + stream >> [other interesting data]; + </pre> + +<p> 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. +<p> <a name="raw"></a> +<h3> Reading and writing raw binary data +</h3> +<a name="1"></a><p> 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 char* using <a href="#readRawBytes">readRawBytes</a>(). Similarly data can be +written to the stream using <a href="#writeRawBytes">writeRawBytes</a>(). Notice that any +encoding/decoding of the data must be done by you. +<p> A similar pair of functions is <a href="#readBytes">readBytes</a>() and <a href="#writeBytes">writeBytes</a>(). These +differ from their <em>raw</em> counterparts as follows: readBytes() +reads a Q_UINT32 which is taken to be the length of the data to be +read, then that number of bytes is read into the preallocated +char*; writeBytes() writes a Q_UINT32 containing the length of the +data, followed by the data. Notice that any encoding/decoding of +the data (apart from the length Q_UINT32) must be done by you. +<p> <p>See also <a href="qtextstream.html">QTextStream</a>, <a href="qvariant.html">QVariant</a>, and <a href="io.html">Input/Output and Networking</a>. + +<hr><h2>Member Type Documentation</h2> +<h3 class=fn><a name="ByteOrder-enum"></a>QDataStream::ByteOrder</h3> + +<p> The byte order used for reading/writing the data. +<ul> +<li><tt>QDataStream::BigEndian</tt> - the default +<li><tt>QDataStream::LittleEndian</tt> +</ul> +<hr><h2>Member Function Documentation</h2> +<h3 class=fn><a name="QDataStream"></a>QDataStream::QDataStream () +</h3> +Constructs a data stream that has no IO device. +<p> <p>See also <a href="#setDevice">setDevice</a>(). + +<h3 class=fn><a name="QDataStream-2"></a>QDataStream::QDataStream ( <a href="qiodevice.html">QIODevice</a> * d ) +</h3> +Constructs a data stream that uses the IO device <em>d</em>. +<p> <b>Warning:</b> If you use <a href="qsocket.html">QSocket</a> or <a href="qsocketdevice.html">QSocketDevice</a> as the IO device <em>d</em> +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. +<p> <p>See also <a href="#setDevice">setDevice</a>() and <a href="#device">device</a>(). + +<h3 class=fn><a name="QDataStream-3"></a>QDataStream::QDataStream ( <a href="qbytearray.html">QByteArray</a> a, int mode ) +</h3> +Constructs a data stream that operates on a byte array, <em>a</em>, +through an internal <a href="qbuffer.html">QBuffer</a> device. The <em>mode</em> is a +<a href="qiodevice.html#mode">QIODevice::mode</a>(), usually either <a href="qfile.html#open">IO_ReadOnly</a> or <a href="qfile.html#open">IO_WriteOnly</a>. +<p> Example: +<pre> + static char bindata[] = { 231, 1, 44, ... }; + <a href="qbytearray.html">QByteArray</a> a; + a.<a href="qmemarray.html#setRawData">setRawData</a>( bindata, sizeof(bindata) ); // a points to bindata + QDataStream stream( a, <a href="qfile.html#open">IO_ReadOnly</a> ); // open on a's data + stream >> [something]; // read raw bindata + a.<a href="qmemarray.html#resetRawData">resetRawData</a>( bindata, sizeof(bindata) ); // finished + </pre> + +<p> The <a href="qmemarray.html#setRawData">QByteArray::setRawData</a>() function is not for the inexperienced. + +<h3 class=fn><a name="~QDataStream"></a>QDataStream::~QDataStream ()<tt> [virtual]</tt> +</h3> +Destroys the data stream. +<p> The destructor will not affect the current IO device, unless it is +an internal IO device processing a <a href="qbytearray.html">QByteArray</a> passed in the <em>constructor</em>, in which case the internal IO device is destroyed. + +<h3 class=fn>bool <a name="atEnd"></a>QDataStream::atEnd () const +</h3> + +<p> Returns TRUE if the IO device has reached the end position (end of +the stream or file) or if there is no IO device set; otherwise +returns FALSE, i.e. if the current position of the IO device is +before the end position. +<p> <p>See also <a href="qiodevice.html#atEnd">QIODevice::atEnd</a>(). + +<h3 class=fn>int <a name="byteOrder"></a>QDataStream::byteOrder () const +</h3> + +<p> Returns the current byte order setting -- either <a href="#ByteOrder-enum">BigEndian</a> or +<a href="#ByteOrder-enum">LittleEndian</a>. +<p> <p>See also <a href="#setByteOrder">setByteOrder</a>(). + +<h3 class=fn><a href="qiodevice.html">QIODevice</a> * <a name="device"></a>QDataStream::device () const +</h3> + +<p> Returns the IO device currently set. +<p> <p>See also <a href="#setDevice">setDevice</a>() and <a href="#unsetDevice">unsetDevice</a>(). + +<h3 class=fn>bool <a name="eof"></a>QDataStream::eof () const +</h3> +<p> <b>This function is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code. +<p> Returns TRUE if the IO device has reached the end position (end of +stream or file) or if there is no IO device set. +<p> Returns FALSE if the current position of the read/write head of the IO +device is somewhere before the end position. +<p> <p>See also <a href="qiodevice.html#atEnd">QIODevice::atEnd</a>(). + +<h3 class=fn>bool <a name="isPrintableData"></a>QDataStream::isPrintableData () const +</h3> + +<p> Returns TRUE if the printable data flag has been set; otherwise +returns FALSE. +<p> <p>See also <a href="#setPrintableData">setPrintableData</a>(). + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt"></a>QDataStream::operator<< ( Q_INT8 i ) +</h3> +Writes a signed byte, <em>i</em>, to the stream and returns a reference +to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-2"></a>QDataStream::operator<< ( Q_UINT8 i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes an unsigned byte, <em>i</em>, to the stream and returns a +reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-3"></a>QDataStream::operator<< ( Q_INT16 i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes a signed 16-bit integer, <em>i</em>, to the stream and returns a +reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-4"></a>QDataStream::operator<< ( Q_UINT16 i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes an unsigned 16-bit integer, <em>i</em>, to the stream and returns +a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-5"></a>QDataStream::operator<< ( Q_INT32 i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes a signed 32-bit integer, <em>i</em>, to the stream and returns a +reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-6"></a>QDataStream::operator<< ( Q_UINT32 i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes an unsigned integer, <em>i</em>, to the stream as a 32-bit +unsigned integer (Q_UINT32). Returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-7"></a>QDataStream::operator<< ( Q_INT64 i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes a signed 64-bit integer, <em>i</em>, to the stream and returns a +reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-8"></a>QDataStream::operator<< ( Q_UINT64 i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes an unsigned 64-bit integer, <em>i</em>, to the stream and returns a +reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-9"></a>QDataStream::operator<< ( Q_LONG i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes a signed integer <em>i</em>, of the system's word length, to the +stream and returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-a"></a>QDataStream::operator<< ( Q_ULONG i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes an unsigned integer <em>i</em>, of the system's word length, to +the stream and returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-b"></a>QDataStream::operator<< ( float f ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes a 32-bit floating point number, <em>f</em>, to the stream using +the standard IEEE754 format. Returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-c"></a>QDataStream::operator<< ( double f ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes a 64-bit floating point number, <em>f</em>, to the stream using +the standard IEEE754 format. Returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-lt-lt-d"></a>QDataStream::operator<< ( const char * s ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Writes the '\0'-terminated string <em>s</em> to the stream and returns a +reference to the stream. +<p> The string is serialized using <a href="#writeBytes">writeBytes</a>(). + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt"></a>QDataStream::operator>> ( Q_INT8 & i ) +</h3> +Reads a signed byte from the stream into <em>i</em>, and returns a +reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-2"></a>QDataStream::operator>> ( Q_UINT8 & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads an unsigned byte from the stream into <em>i</em>, and returns a +reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-3"></a>QDataStream::operator>> ( Q_INT16 & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads a signed 16-bit integer from the stream into <em>i</em>, and +returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-4"></a>QDataStream::operator>> ( Q_UINT16 & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads an unsigned 16-bit integer from the stream into <em>i</em>, and +returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-5"></a>QDataStream::operator>> ( Q_INT32 & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads a signed 32-bit integer from the stream into <em>i</em>, and +returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-6"></a>QDataStream::operator>> ( Q_UINT32 & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads an unsigned 32-bit integer from the stream into <em>i</em>, and +returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-7"></a>QDataStream::operator>> ( Q_INT64 & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads a signed 64-bit integer from the stream into <em>i</em>, and +returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-8"></a>QDataStream::operator>> ( Q_UINT64 & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads an unsigned 64-bit integer from the stream, into <em>i</em>, and +returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-9"></a>QDataStream::operator>> ( Q_LONG & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads a signed integer of the system's word length from the stream +into <em>i</em>, and returns a reference to the stream. +<p> +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-a"></a>QDataStream::operator>> ( Q_ULONG & i ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads an unsigned integer of the system's word length from the +stream, into <em>i</em>, and returns a reference to the stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-b"></a>QDataStream::operator>> ( float & f ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads a 32-bit floating point number from the stream into <em>f</em>, +using the standard IEEE754 format. Returns a reference to the +stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-c"></a>QDataStream::operator>> ( double & f ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads a 64-bit floating point number from the stream into <em>f</em>, +using the standard IEEE754 format. Returns a reference to the +stream. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="operator-gt-gt-d"></a>QDataStream::operator>> ( char *& s ) +</h3> +This is an overloaded member function, provided for convenience. It behaves essentially like the above function. +<p> Reads the '\0'-terminated string <em>s</em> from the stream and returns +a reference to the stream. +<p> Space for the string is allocated using <tt>new</tt> -- the caller must +destroy it with delete[]. + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="readBytes"></a>QDataStream::readBytes ( char *& s, uint & l ) +</h3> +Reads the buffer <em>s</em> from the stream and returns a reference to +the stream. +<p> The buffer <em>s</em> is allocated using <tt>new</tt>. Destroy it with the <tt>delete[]</tt> operator. If the length is zero or <em>s</em> cannot be +allocated, <em>s</em> is set to 0. +<p> The <em>l</em> parameter will be set to the length of the buffer. +<p> The serialization format is a Q_UINT32 length specifier first, +then <em>l</em> bytes of data. Note that the data is <em>not</em> encoded. +<p> <p>See also <a href="#readRawBytes">readRawBytes</a>() and <a href="#writeBytes">writeBytes</a>(). + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="readRawBytes"></a>QDataStream::readRawBytes ( char * s, uint len ) +</h3> +Reads <em>len</em> bytes from the stream into <em>s</em> and returns a +reference to the stream. +<p> The buffer <em>s</em> must be preallocated. The data is <em>not</em> encoded. +<p> <p>See also <a href="#readBytes">readBytes</a>(), <a href="qiodevice.html#readBlock">QIODevice::readBlock</a>(), and <a href="#writeRawBytes">writeRawBytes</a>(). + +<h3 class=fn>void <a name="setByteOrder"></a>QDataStream::setByteOrder ( int bo ) +</h3> +Sets the serialization byte order to <em>bo</em>. +<p> The <em>bo</em> parameter can be <a href="#ByteOrder-enum">QDataStream::BigEndian</a> or <a href="#ByteOrder-enum">QDataStream::LittleEndian</a>. +<p> The default setting is big endian. We recommend leaving this +setting unless you have special requirements. +<p> <p>See also <a href="#byteOrder">byteOrder</a>(). + +<h3 class=fn>void <a name="setDevice"></a>QDataStream::setDevice ( <a href="qiodevice.html">QIODevice</a> * d ) +</h3> +void <a href="#setDevice">QDataStream::setDevice</a>(<a href="qiodevice.html">QIODevice</a> *d ) +<p> Sets the IO device to <em>d</em>. +<p> <p>See also <a href="#device">device</a>() and <a href="#unsetDevice">unsetDevice</a>(). + +<h3 class=fn>void <a name="setPrintableData"></a>QDataStream::setPrintableData ( bool enable ) +</h3> + +<p> If <em>enable</em> is TRUE, data will be output in a human readable +format. If <em>enable</em> is FALSE, data will be output in a binary +format. +<p> If <em>enable</em> is TRUE, the write functions will generate output +that consists of printable characters (7 bit ASCII). This output +will typically be a lot larger than the default binary output, and +consequently slower to write. +<p> We recommend only enabling printable data for debugging purposes. + +<h3 class=fn>void <a name="setVersion"></a>QDataStream::setVersion ( int v ) +</h3> + +<p> Sets the version number of the data serialization format to <em>v</em>. +<p> You don't need to set a version if you are using the current +version of Qt. +<p> 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 of QDataStream. +<p> <center><table cellpadding="4" cellspacing="2" border="0"> +<tr bgcolor="#a2c511"> <th valign="top">Qt Version <th valign="top">QDataStream Version +<tr bgcolor="#f0f0f0"> <td valign="top">Qt 3.3 <td valign="top" colspan="1" rowspan="1"> 6 +<tr bgcolor="#d0d0d0"> <td valign="top">Qt 3.2 <td valign="top" colspan="1" rowspan="1"> 5 +<tr bgcolor="#f0f0f0"> <td valign="top">Qt 3.1 <td valign="top" colspan="1" rowspan="1"> 5 +<tr bgcolor="#d0d0d0"> <td valign="top">Qt 3.0 <td valign="top" colspan="1" rowspan="1"> 4 +<tr bgcolor="#f0f0f0"> <td valign="top">Qt 2.1.x and Qt 2.2.x <td valign="top" colspan="1" rowspan="1"> 3 +<tr bgcolor="#d0d0d0"> <td valign="top">Qt 2.0.x <td valign="top" colspan="1" rowspan="1"> 2 +<tr bgcolor="#f0f0f0"> <td valign="top">Qt 1.x <td valign="top" colspan="1" rowspan="1"> 1 +</table></center> +<p> <p>See also <a href="#version">version</a>(). + +<h3 class=fn>void <a name="unsetDevice"></a>QDataStream::unsetDevice () +</h3> +Unsets the IO device. This is the same as calling <a href="#setDevice">setDevice</a>( 0 ). +<p> <p>See also <a href="#device">device</a>() and <a href="#setDevice">setDevice</a>(). + +<h3 class=fn>int <a name="version"></a>QDataStream::version () const +</h3> + +<p> Returns the version number of the data serialization format. In Qt +3.1, this number is 5. +<p> <p>See also <a href="#setVersion">setVersion</a>(). + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="writeBytes"></a>QDataStream::writeBytes ( const char * s, uint len ) +</h3> +Writes the length specifier <em>len</em> and the buffer <em>s</em> to the +stream and returns a reference to the stream. +<p> The <em>len</em> is serialized as a Q_UINT32, followed by <em>len</em> bytes +from <em>s</em>. Note that the data is <em>not</em> encoded. +<p> <p>See also <a href="#writeRawBytes">writeRawBytes</a>() and <a href="#readBytes">readBytes</a>(). + +<h3 class=fn><a href="qdatastream.html">QDataStream</a> & <a name="writeRawBytes"></a>QDataStream::writeRawBytes ( const char * s, uint len ) +</h3> +Writes <em>len</em> bytes from <em>s</em> to the stream and returns a +reference to the stream. The data is <em>not</em> encoded. +<p> <p>See also <a href="#writeBytes">writeBytes</a>(), <a href="qiodevice.html#writeBlock">QIODevice::writeBlock</a>(), and <a href="#readRawBytes">readRawBytes</a>(). + +<!-- eof --> +<hr><p> +This file is part of the <a href="index.html">Qt toolkit</a>. +Copyright © 1995-2007 +<a href="http://www.trolltech.com/">Trolltech</a>. 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