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.
243 lines
12 KiB
243 lines
12 KiB
13 years ago
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
|
||
5 months ago
|
<!-- /home/espenr/tmp/qt-3.3.8-espenr-2499/qt-x11-free-3.3.8/doc/tqintcache.doc:41 -->
|
||
|
13 years ago
|
<html>
|
||
|
|
<head>
|
||
|
|
<meta http-equiv="Content-Type" content="text/html; charset=ISO-8859-1">
|
||
|
|
<title>TQIntCache 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>TQIntCache Class Reference</h1>
|
||
|
|
|
||
|
|
<p>The TQIntCache class is a template class that provides a cache based on long keys.
|
||
|
|
<a href="#details">More...</a>
|
||
|
5 months ago
|
<p><tt>#include <<a href="tqintcache-h.html">tqintcache.h</a>></tt>
|
||
|
6 months ago
|
<p>Inherits <a href="tqptrcollection.html">TQPtrCollection</a>.
|
||
|
5 months ago
|
<p><a href="tqintcache-members.html">List of all member functions.</a>
|
||
|
13 years ago
|
<h2>Public Members</h2>
|
||
|
|
<ul>
|
||
|
|
<li class=fn><a href="#TQIntCache-2"><b>TQIntCache</b></a> ( int maxCost = 100, int size = 17 )</li>
|
||
|
|
<li class=fn><a href="#~TQIntCache"><b>~TQIntCache</b></a> ()</li>
|
||
|
|
<li class=fn>int <a href="#maxCost"><b>maxCost</b></a> () const</li>
|
||
|
|
<li class=fn>int <a href="#totalCost"><b>totalCost</b></a> () const</li>
|
||
|
|
<li class=fn>void <a href="#setMaxCost"><b>setMaxCost</b></a> ( int m )</li>
|
||
|
|
<li class=fn>virtual uint <a href="#count"><b>count</b></a> () const</li>
|
||
|
|
<li class=fn>uint <a href="#size"><b>size</b></a> () const</li>
|
||
|
|
<li class=fn>bool <a href="#isEmpty"><b>isEmpty</b></a> () const</li>
|
||
|
|
<li class=fn>bool <a href="#insert"><b>insert</b></a> ( long k, const type * d, int c = 1, int p = 0 )</li>
|
||
|
|
<li class=fn>bool <a href="#remove"><b>remove</b></a> ( long k )</li>
|
||
|
|
<li class=fn>type * <a href="#take"><b>take</b></a> ( long k )</li>
|
||
|
|
<li class=fn>virtual void <a href="#clear"><b>clear</b></a> ()</li>
|
||
|
|
<li class=fn>type * <a href="#find"><b>find</b></a> ( long k, bool ref = TRUE ) const</li>
|
||
|
|
<li class=fn>type * <a href="#operator[]"><b>operator[]</b></a> ( long k ) const</li>
|
||
|
|
<li class=fn>void <a href="#statistics"><b>statistics</b></a> () const</li>
|
||
|
|
</ul>
|
||
|
|
<hr><a name="details"></a><h2>Detailed Description</h2>
|
||
|
|
|
||
|
|
|
||
|
|
The TQIntCache class is a template class that provides a cache based on long keys.
|
||
|
|
<p>
|
||
|
|
|
||
|
|
<p> TQIntCache is implemented as a template class. Define a template
|
||
|
|
instance TQIntCache<X> to create a cache that operates on
|
||
|
|
pointers to X, or X*.
|
||
|
|
<p> A cache is a least recently used (LRU) list of cache items,
|
||
|
|
accessed via <tt>long</tt> keys. Each cache item has a cost. The sum
|
||
|
|
of item costs, <a href="#totalCost">totalCost</a>(), will not exceed the maximum cache
|
||
|
|
cost, <a href="#maxCost">maxCost</a>(). If inserting a new item would cause the total
|
||
|
|
cost to exceed the maximum cost, the least recently used items in
|
||
|
|
the cache are removed.
|
||
|
|
<p> Apart from <a href="#insert">insert</a>(), by far the most important function is <a href="#find">find</a>()
|
||
|
|
(which also exists as operator[]). This function looks up an
|
||
|
|
item, returns it, and by default marks it as being the most
|
||
|
|
recently used item.
|
||
|
|
<p> There are also methods to <a href="#remove">remove</a>() or <a href="#take">take</a>() an object from the
|
||
|
6 months ago
|
cache. Calling <a href="tqptrcollection.html#setAutoDelete">setAutoDelete</a>(TRUE) for a cache tells it to delete
|
||
|
13 years ago
|
items that are removed. The default is to not delete items when
|
||
|
|
they are removed (i.e. remove() and take() are equivalent).
|
||
|
|
<p> When inserting an item into the cache, only the pointer is copied,
|
||
|
|
not the item itself. This is called a <a href="shclass.html#shallow-copy">shallow copy</a>. It is possible
|
||
|
|
to make the cache copy all of the item's data (known as a <a href="shclass.html#deep-copy">deep copy</a>) when an item is inserted. insert() calls the virtual
|
||
|
6 months ago
|
function <a href="tqptrcollection.html#newItem">TQPtrCollection::newItem</a>() for the item to be inserted.
|
||
|
|
Inherit a dictionary and reimplement <a href="tqptrcollection.html#newItem">newItem</a>() if you want deep
|
||
|
13 years ago
|
copies.
|
||
|
|
<p> When removing a cache item, the item will be automatically
|
||
|
|
deleted if auto-deletion is enabled.
|
||
|
5 months ago
|
<p> There is a <a href="tqintcacheiterator.html">TQIntCacheIterator</a> which may be used to traverse the
|
||
|
13 years ago
|
items in the cache in arbitrary order.
|
||
|
5 months ago
|
<p> <p>See also <a href="tqintcacheiterator.html">TQIntCacheIterator</a>, <a href="tqcache.html">TQCache</a>, <a href="tqasciicache.html">TQAsciiCache</a>, <a href="collection.html">Collection Classes</a>, and <a href="tools.html">Non-GUI Classes</a>.
|
||
|
13 years ago
|
|
||
|
|
<hr><h2>Member Function Documentation</h2>
|
||
|
|
<h3 class=fn><a name="TQIntCache-2"></a>TQIntCache::TQIntCache ( int maxCost = 100, int size = 17 )
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Constructs a cache whose contents will never have a total cost
|
||
|
|
greater than <em>maxCost</em> and which is expected to contain less than
|
||
|
|
<em>size</em> items.
|
||
|
|
<p> <em>size</em> is actually the size of an internal hash array; it's
|
||
|
|
usually best to make it <a href="primes.html#prime">prime</a> and at least 50% bigger than the
|
||
|
|
largest expected number of items in the cache.
|
||
|
|
<p> Each inserted item is associated with a cost. When inserting a new
|
||
|
|
item, if the total cost of all items in the cache will exceed <em>maxCost</em>, the cache will start throwing out the older (least
|
||
|
|
recently used) items until there is enough room for the new item
|
||
|
|
to be inserted.
|
||
|
|
|
||
|
|
<h3 class=fn><a name="~TQIntCache"></a>TQIntCache::~TQIntCache ()
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Removes all items from the cache and then destroys the int cache.
|
||
|
|
If auto-deletion is enabled the cache's items are deleted. All
|
||
|
|
iterators that access this cache will be reset.
|
||
|
|
|
||
|
|
<h3 class=fn>void <a name="clear"></a>TQIntCache::clear ()<tt> [virtual]</tt>
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Removes all items from the cache, and deletes them if
|
||
|
|
auto-deletion has been enabled.
|
||
|
|
<p> All cache iterators that operate this on cache are reset.
|
||
|
|
<p> <p>See also <a href="#remove">remove</a>() and <a href="#take">take</a>().
|
||
|
|
|
||
|
6 months ago
|
<p>Reimplemented from <a href="tqptrcollection.html#clear">TQPtrCollection</a>.
|
||
|
13 years ago
|
<h3 class=fn>uint <a name="count"></a>TQIntCache::count () const<tt> [virtual]</tt>
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Returns the number of items in the cache.
|
||
|
|
<p> <p>See also <a href="#totalCost">totalCost</a>().
|
||
|
|
|
||
|
6 months ago
|
<p>Reimplemented from <a href="tqptrcollection.html#count">TQPtrCollection</a>.
|
||
|
13 years ago
|
<h3 class=fn>type * <a name="find"></a>TQIntCache::find ( long k, bool ref = TRUE ) const
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Returns the item associated with <em>k</em>, or 0 if the key does not
|
||
|
|
exist in the cache. If <em>ref</em> is TRUE (the default), the item is
|
||
|
|
moved to the front of the least recently used list.
|
||
|
|
<p> If there are two or more items with equal keys, the one that was
|
||
|
|
inserted most recently is returned.
|
||
|
|
|
||
|
|
<h3 class=fn>bool <a name="insert"></a>TQIntCache::insert ( long k, const type * d, int c = 1, int p = 0 )
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Inserts the item <em>d</em> into the cache with key <em>k</em> and assigns it
|
||
|
|
a cost of <em>c</em> (default 1). Returns TRUE if it succeeds; otherwise
|
||
|
|
returns FALSE.
|
||
|
|
<p> The cache's size is limited, and if the total cost is too high,
|
||
|
|
TQIntCache will remove old, least-used items until there is room
|
||
|
|
for this new item.
|
||
|
|
<p> The parameter <em>p</em> is internal and should be left at the default
|
||
|
|
value (0).
|
||
|
|
<p> <b>Warning:</b> If this function returns FALSE (for example, the cost <tt>,</tt>
|
||
|
|
exceeds <a href="#maxCost">maxCost</a>()), you must delete <em>d</em> yourself. Additionally,
|
||
|
|
be very careful about using <em>d</em> after calling this function. Any
|
||
|
|
other insertions into the cache, from anywhere in the application
|
||
|
|
or within TQt itself, could cause the object to be discarded from
|
||
|
|
the cache and the pointer to become invalid.
|
||
|
|
|
||
|
|
<h3 class=fn>bool <a name="isEmpty"></a>TQIntCache::isEmpty () const
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Returns TRUE if the cache is empty; otherwise returns FALSE.
|
||
|
|
|
||
|
|
<h3 class=fn>int <a name="maxCost"></a>TQIntCache::maxCost () const
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Returns the maximum allowed total cost of the cache.
|
||
|
|
<p> <p>See also <a href="#setMaxCost">setMaxCost</a>() and <a href="#totalCost">totalCost</a>().
|
||
|
|
|
||
|
|
<h3 class=fn>type * <a name="operator[]"></a>TQIntCache::operator[] ( long k ) const
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Returns the item associated with <em>k</em>, or 0 if <em>k</em> does not exist
|
||
|
|
in the cache, and moves the item to the front of the least
|
||
|
|
recently used list.
|
||
|
|
<p> If there are two or more items with equal keys, the one that was
|
||
|
|
inserted most recently is returned.
|
||
|
|
<p> This is the same as <a href="#find">find</a>( k, TRUE ).
|
||
|
|
<p> <p>See also <a href="#find">find</a>().
|
||
|
|
|
||
|
|
<h3 class=fn>bool <a name="remove"></a>TQIntCache::remove ( long k )
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Removes the item associated with <em>k</em>, and returns TRUE if the
|
||
|
|
item was present in the cache; otherwise returns FALSE.
|
||
|
|
<p> The item is deleted if auto-deletion has been enabled, i.e. if you
|
||
|
6 months ago
|
have called <a href="tqptrcollection.html#setAutoDelete">setAutoDelete</a>(TRUE).
|
||
|
13 years ago
|
<p> If there are two or more items with equal keys, the one that was
|
||
|
|
inserted most recently is removed.
|
||
|
|
<p> All iterators that refer to the removed item are set to point to
|
||
|
|
the next item in the cache's traversal order.
|
||
|
|
<p> <p>See also <a href="#take">take</a>() and <a href="#clear">clear</a>().
|
||
|
|
|
||
|
|
<h3 class=fn>void <a name="setMaxCost"></a>TQIntCache::setMaxCost ( int m )
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Sets the maximum allowed total cost of the cache to <em>m</em>. If the
|
||
|
|
current total cost is greater than <em>m</em>, some items are removed
|
||
|
|
immediately.
|
||
|
|
<p> <p>See also <a href="#maxCost">maxCost</a>() and <a href="#totalCost">totalCost</a>().
|
||
|
|
|
||
|
|
<h3 class=fn>uint <a name="size"></a>TQIntCache::size () const
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Returns the size of the hash array used to implement the cache.
|
||
|
|
This should be a bit larger than <a href="#count">count</a>() is likely to be.
|
||
|
|
|
||
|
|
<h3 class=fn>void <a name="statistics"></a>TQIntCache::statistics () const
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> A debug-only utility function. Prints out cache usage, hit/miss,
|
||
|
12 years ago
|
and distribution information using <a href="ntqapplication.html#qDebug">tqDebug</a>(). This function does
|
||
|
13 years ago
|
nothing in the release library.
|
||
|
|
|
||
|
|
<h3 class=fn>type * <a name="take"></a>TQIntCache::take ( long k )
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Takes the item associated with <em>k</em> out of the cache without
|
||
|
|
deleting it, and returns a pointer to the item taken out or 0 if
|
||
|
|
the key does not exist in the cache.
|
||
|
|
<p> If there are two or more items with equal keys, the one that was
|
||
|
|
inserted most recently is taken.
|
||
|
|
<p> All iterators that refer to the taken item are set to point to the
|
||
|
|
next item in the cache's traversal order.
|
||
|
|
<p> <p>See also <a href="#remove">remove</a>() and <a href="#clear">clear</a>().
|
||
|
|
|
||
|
|
<h3 class=fn>int <a name="totalCost"></a>TQIntCache::totalCost () const
|
||
|
|
</h3>
|
||
|
|
|
||
|
|
<p> Returns the total cost of the items in the cache. This is an
|
||
|
|
integer in the range 0 to <a href="#maxCost">maxCost</a>().
|
||
|
|
<p> <p>See also <a href="#setMaxCost">setMaxCost</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>
|