<!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/qbuffer.cpp:41 --> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1"> <title>TQBuffer 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>TQBuffer Class Reference</h1> <p>The TQBuffer class is an I/O device that operates on a TQByteArray. <a href="#details">More...</a> <p>All the functions in this class are <a href="threads.html#reentrant">reentrant</a> when TQt is built with thread support.</p> <p><tt>#include <<a href="qbuffer-h.html">ntqbuffer.h</a>></tt> <p>Inherits <a href="ntqiodevice.html">TQIODevice</a>. <p><a href="qbuffer-members.html">List of all member functions.</a> <h2>Public Members</h2> <ul> <li class=fn><a href="#TQBuffer"><b>TQBuffer</b></a> ()</li> <li class=fn><a href="#TQBuffer-2"><b>TQBuffer</b></a> ( TQByteArray buf )</li> <li class=fn><a href="#~TQBuffer"><b>~TQBuffer</b></a> ()</li> <li class=fn>TQByteArray <a href="#buffer"><b>buffer</b></a> () const</li> <li class=fn>bool <a href="#setBuffer"><b>setBuffer</b></a> ( TQByteArray buf )</li> <li class=fn>virtual Q_LONG <a href="#writeBlock"><b>writeBlock</b></a> ( const char * p, Q_ULONG len )</li> <li class=fn>Q_LONG <a href="#writeBlock-2"><b>writeBlock</b></a> ( const TQByteArray & data )</li> </ul> <hr><a name="details"></a><h2>Detailed Description</h2> The TQBuffer class is an I/O device that operates on a <a href="qbytearray.html">TQByteArray</a>. <p> <p> TQBuffer is used to read and write to a memory buffer. It is normally used with a <a href="ntqtextstream.html">TQTextStream</a> or a <a href="ntqdatastream.html">TQDataStream</a>. TQBuffer has an associated TQByteArray which holds the buffer data. The <a href="ntqiodevice.html#size">size</a>() of the buffer is automatically adjusted as data is written. <p> The constructor <tt>TQBuffer(TQByteArray)</tt> creates a TQBuffer using an existing byte array. The byte array can also be set with <a href="#setBuffer">setBuffer</a>(). Writing to the TQBuffer will modify the original byte array because TQByteArray is <a href="shclass.html">explicitly shared.</a> <p> Use <a href="ntqiodevice.html#open">open</a>() to open the buffer before use and to set the mode (read-only, write-only, etc.). <a href="ntqiodevice.html#close">close</a>() closes the buffer. The buffer must be closed before reopening or calling setBuffer(). <p> A common way to use TQBuffer is through <a href="ntqdatastream.html">TQDataStream</a> or <a href="ntqtextstream.html">TQTextStream</a>, which have constructors that take a TQBuffer parameter. For convenience, there are also TQDataStream and <a href="ntqtextstream.html">TQTextStream</a> constructors that take a <a href="qbytearray.html">TQByteArray</a> parameter. These constructors create and open an internal TQBuffer. <p> Note that TQTextStream can also operate on a <a href="ntqstring.html">TQString</a> (a Unicode string); a TQBuffer cannot. <p> You can also use TQBuffer directly through the standard <a href="ntqiodevice.html">TQIODevice</a> functions <a href="ntqiodevice.html#readBlock">readBlock</a>(), <a href="#writeBlock">writeBlock</a>() <a href="ntqiodevice.html#readLine">readLine</a>(), <a href="ntqiodevice.html#at">at</a>(), <a href="ntqiodevice.html#getch">getch</a>(), <a href="ntqiodevice.html#putch">putch</a>() and <a href="ntqiodevice.html#ungetch">ungetch</a>(). <p> <p>See also <a href="ntqfile.html">TQFile</a>, <a href="ntqdatastream.html">TQDataStream</a>, <a href="ntqtextstream.html">TQTextStream</a>, <a href="qbytearray.html">TQByteArray</a>, <a href="shclass.html">Shared Classes</a>, <a href="collection.html">Collection Classes</a>, and <a href="io.html">Input/Output and Networking</a>. <hr><h2>Member Function Documentation</h2> <h3 class=fn><a name="TQBuffer"></a>TQBuffer::TQBuffer () </h3> Constructs an empty buffer. <h3 class=fn><a name="TQBuffer-2"></a>TQBuffer::TQBuffer ( <a href="qbytearray.html">TQByteArray</a> buf ) </h3> Constructs a buffer that operates on <em>buf</em>. <p> If you open the buffer in write mode (<a href="ntqfile.html#open"><a href="ntqfile.html#open">IO_WriteOnly</a></a> or <a href="ntqfile.html#open">IO_ReadWrite</a>) and write something into the buffer, <em>buf</em> will be modified. <p> Example: <pre> <a href="ntqcstring.html">TQCString</a> str = "abc"; TQBuffer b( str ); b.<a href="ntqiodevice.html#open">open</a>( IO_WriteOnly ); b.<a href="ntqiodevice.html#at">at</a>( 3 ); // position at the 4th character (the terminating \0) b.<a href="#writeBlock">writeBlock</a>( "def", 4 ); // write "def" including the terminating \0 b.<a href="ntqiodevice.html#close">close</a>(); // Now, str == "abcdef" with a terminating \0 </pre> <p> <p>See also <a href="#setBuffer">setBuffer</a>(). <h3 class=fn><a name="~TQBuffer"></a>TQBuffer::~TQBuffer () </h3> Destroys the buffer. <h3 class=fn><a href="qbytearray.html">TQByteArray</a> <a name="buffer"></a>TQBuffer::buffer () const </h3> <p> Returns this buffer's byte array. <p> <p>See also <a href="#setBuffer">setBuffer</a>(). <h3 class=fn>bool <a name="setBuffer"></a>TQBuffer::setBuffer ( <a href="qbytearray.html">TQByteArray</a> buf ) </h3> Replaces the buffer's contents with <em>buf</em> and returns TRUE. <p> Does nothing (and returns FALSE) if <a href="ntqiodevice.html#isOpen">isOpen</a>() is TRUE. <p> Note that if you open the buffer in write mode (<a href="ntqfile.html#open"><a href="ntqfile.html#open">IO_WriteOnly</a></a> or <a href="ntqfile.html#open">IO_ReadWrite</a>) and write something into the buffer, <em>buf</em> is also modified because <a href="qbytearray.html">TQByteArray</a> is an <a href="shclass.html#explicitly-shared">explicitly shared</a> class. <p> <p>See also <a href="#buffer">buffer</a>(), <a href="ntqiodevice.html#open">open</a>(), and <a href="ntqiodevice.html#close">close</a>(). <h3 class=fn>Q_LONG <a name="writeBlock"></a>TQBuffer::writeBlock ( const char * p, Q_ULONG len )<tt> [virtual]</tt> </h3> Writes <em>len</em> bytes from <em>p</em> into the buffer at the current index position, overwriting any characters there and extending the buffer if necessary. Returns the number of bytes actually written. <p> Returns -1 if an error occurred. <p> <p>See also <a href="ntqiodevice.html#readBlock">readBlock</a>(). <p>Reimplemented from <a href="ntqiodevice.html#writeBlock">TQIODevice</a>. <h3 class=fn>Q_LONG <a name="writeBlock-2"></a>TQBuffer::writeBlock ( const <a href="qbytearray.html">TQByteArray</a> & data ) </h3> This is an overloaded member function, provided for convenience. It behaves essentially like the above function. <p> This convenience function is the same as calling <tt>writeBlock( data.data(), data.size() )</tt> with <em>data</em>. <!-- eof --> <hr><p> This file is part of the <a href="index.html">TQt toolkit</a>. Copyright © 1995-2007 <a href="http://www.trolltech.com/">Trolltech</a>. All Rights Reserved.<p><address><hr><div align=center> <table width=100% cellspacing=0 border=0><tr> <td>Copyright © 2007 <a href="troll.html">Trolltech</a><td align=center><a href="trademarks.html">Trademarks</a> <td align=right><div align=right>TQt 3.3.8</div> </table></div></address></body> </html>