You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
121 lines
6.0 KiB
121 lines
6.0 KiB
13 years ago
|
<!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/kernel/qasyncio.cpp:131 -->
|
||
|
|
<html>
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
||
|
|
<title>TQDataSource 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>TQDataSource Class Reference<br><small>[obsolete]</small></h1>
|
||
|
|
|
||
|
|
<p>The TQDataSource class is an asynchronous producer of data.
|
||
|
|
<a href="#details">More...</a>
|
||
|
|
<p><tt>#include <<a href="qasyncio-h.html">qasyncio.h</a>></tt>
|
||
|
|
<p>Inherits <a href="qasyncio.html">TQAsyncIO</a>.
|
||
|
|
<p>Inherited by <a href="qiodevicesource.html">TQIODeviceSource</a>.
|
||
|
|
<p><a href="qdatasource-members.html">List of all member functions.</a>
|
||
|
|
<h2>Public Members</h2>
|
||
|
|
<ul>
|
||
|
|
<li class=fn>virtual int <a href="#readyToSend"><b>readyToSend</b></a> () = 0</li>
|
||
|
|
<li class=fn>virtual void <a href="#sendTo"><b>sendTo</b></a> ( TQDataSink *, int count ) = 0</li>
|
||
|
|
<li class=fn>void <a href="#maybeReady"><b>maybeReady</b></a> ()</li>
|
||
|
|
<li class=fn>virtual bool <a href="#rewindable"><b>rewindable</b></a> () const</li>
|
||
|
|
<li class=fn>virtual void <a href="#enableRewind"><b>enableRewind</b></a> ( bool on )</li>
|
||
|
|
<li class=fn>virtual void <a href="#rewind"><b>rewind</b></a> ()</li>
|
||
|
|
</ul>
|
||
|
|
<hr><a name="details"></a><h2>Detailed Description</h2>
|
||
|
|
|
||
|
|
|
||
|
|
<b>This class is obsolete.</b> It is provided to keep old source working. We strongly advise against using it in new code.
|
||
|
|
<p> The TQDataSource class is an asynchronous producer of data.
|
||
|
|
<p> A data source is an object which provides data from some source in an
|
||
|
|
asynchronous manner. This means that at some time not determined by
|
||
|
|
the data source, blocks of data will be taken from it for processing.
|
||
|
|
The data source is able to limit the maximum size of such blocks which
|
||
|
|
it is currently able to provide.
|
||
|
|
<p> <p>See also <a href="qasyncio.html">TQAsyncIO</a>, <a href="qdatasink.html">TQDataSink</a>, and <a href="qdatapump.html">TQDataPump</a>.
|
||
|
|
|
||
|
|
<hr><h2>Member Function Documentation</h2>
|
||
|
|
<h3 class=fn>void <a name="enableRewind"></a>TQDataSource::enableRewind ( bool on )<tt> [virtual]</tt>
|
||
|
|
</h3>
|
||
|
|
If this function is called with <em>on</em> set to TRUE, and <a href="#rewindable">rewindable</a>()
|
||
|
|
is TRUE, then the data source must take measures to allow the <a href="#rewind">rewind</a>()
|
||
|
|
function to subsequently operate as described. If rewindable() is FALSE,
|
||
|
|
the function should call <a href="#enableRewind">TQDataSource::enableRewind</a>(), which aborts with
|
||
|
|
a <a href="qapplication.html#qFatal">qFatal</a>() error.
|
||
|
|
<p> For example, a network connection may choose to use a disk cache
|
||
|
|
of input only if rewinding is enabled before the first buffer-full of
|
||
|
|
data is discarded, returning FALSE in rewindable() if that first buffer
|
||
|
|
is discarded.
|
||
|
|
|
||
|
|
<p>Reimplemented in <a href="qiodevicesource.html#enableRewind">TQIODeviceSource</a>.
|
||
|
|
<h3 class=fn>void <a name="maybeReady"></a>TQDataSource::maybeReady ()
|
||
|
|
</h3>
|
||
|
|
This should be called whenever <a href="#readyToSend">readyToSend</a>() might have become non-zero.
|
||
|
|
It is merely calls <a href="qasyncio.html#ready">TQAsyncIO::ready</a>() if readyToSend() is non-zero.
|
||
|
|
|
||
|
|
<h3 class=fn>int <a name="readyToSend"></a>TQDataSource::readyToSend ()<tt> [pure virtual]</tt>
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> The data source should return a value indicating how much data it is ready
|
||
|
|
to provide. This may be 0. If the data source knows it will never be
|
||
|
|
able to provide any more data (until after a <a href="#rewind">rewind</a>()), it may return -1.
|
||
|
|
|
||
|
|
<p>Reimplemented in <a href="qiodevicesource.html#readyToSend">TQIODeviceSource</a>.
|
||
|
|
<h3 class=fn>void <a name="rewind"></a>TQDataSource::rewind ()<tt> [virtual]</tt>
|
||
|
|
</h3>
|
||
|
|
This function rewinds the data source. This may only be called if
|
||
|
|
<a href="#enableRewind">enableRewind</a>(TRUE) has been previously called.
|
||
|
|
|
||
|
|
<p>Reimplemented in <a href="qiodevicesource.html#rewind">TQIODeviceSource</a>.
|
||
|
|
<h3 class=fn>bool <a name="rewindable"></a>TQDataSource::rewindable () const<tt> [virtual]</tt>
|
||
|
|
</h3>
|
||
|
|
This function should return TRUE if the data source can be rewound.
|
||
|
|
<p> The default returns FALSE.
|
||
|
|
|
||
|
|
<p>Reimplemented in <a href="qiodevicesource.html#rewindable">TQIODeviceSource</a>.
|
||
|
|
<h3 class=fn>void <a name="sendTo"></a>TQDataSource::sendTo ( <a href="qdatasink.html">TQDataSink</a> *, int count )<tt> [pure virtual]</tt>
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> This function is called to extract data from the source, by sending
|
||
|
|
it to the given data sink. The <em>count</em> will be no more than the amount
|
||
|
|
indicated by the most recent call to <a href="#readyToSend">readyToSend</a>(). The source must
|
||
|
|
use all the provided data, and the sink will be prepared to accept at
|
||
|
|
least this much data.
|
||
|
|
|
||
|
|
<p>Reimplemented in <a href="qiodevicesource.html#sendTo">TQIODeviceSource</a>.
|
||
|
|
<!-- 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>
|