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<div class="document" id="boost-pointer-container-library">
<h1 class="title"><img alt="Boost" src="cboost.gif" /> Pointer Container Library</h1>
<h2 class="subtitle" id="reference">Reference</h2>
<p>The documentation is divided into a an explanation for
each container. All the common interface is explained only once,
but links are always provided to the relevant links.
Please make sure you understand
the <a class="reference" href="reference.html#the-clonable-concept">Clonable</a> concept and
the <a class="reference" href="reference.html#the-clone-allocator-concept">Clone Allocator</a> concept.</p>
<ul class="simple">
<li><a class="reference" href="conventions.html">Conventions</a></li>
<li><a class="reference" href="#the-clonable-concept">The Clonable concept</a></li>
<li><a class="reference" href="#the-clone-allocator-concept">The Clone Allocator concept</a></li>
<li>Class <a class="reference" href="reversible_ptr_container.html">reversible_ptr_container</a></li>
<li>Class <a class="reference" href="associative_ptr_container.html">associative_ptr_container</a></li>
<li><a class="reference" href="#pointer-container-adapters">Pointer container adapters</a><ul>
<li><a class="reference" href="ptr_sequence_adapter.html">ptr_sequence_adapter</a></li>
<li><a class="reference" href="ptr_set_adapter.html">ptr_set_adapter</a></li>
<li><a class="reference" href="ptr_multiset_adapter.html">ptr_multiset_adapter</a></li>
<li><a class="reference" href="ptr_map_adapter.html">ptr_map_adapter</a></li>
<li><a class="reference" href="ptr_multimap_adapter.html">ptr_multimap_adapter</a></li>
</ul>
</li>
<li><a class="reference" href="#sequence-containers">Sequence containers</a><ul>
<li><a class="reference" href="ptr_vector.html">ptr_vector</a></li>
<li><a class="reference" href="ptr_deque.html">ptr_deque</a></li>
<li><a class="reference" href="ptr_list.html">ptr_list</a></li>
<li><a class="reference" href="ptr_array.html">ptr_array</a></li>
</ul>
</li>
<li><a class="reference" href="#associative-containers">Associative containers</a><ul>
<li><a class="reference" href="ptr_set.html">ptr_set</a></li>
<li><a class="reference" href="ptr_multiset.html">ptr_multiset</a></li>
<li><a class="reference" href="ptr_map.html">ptr_map</a></li>
<li><a class="reference" href="ptr_multimap.html">ptr_multimap</a></li>
</ul>
</li>
<li><a class="reference" href="#map-iterator-operations">Map iterator operations</a></li>
<li><a class="reference" href="indirect_fun.html">Indirected functions</a></li>
<li><a class="reference" href="#class-nullable">Class nullable</a></li>
<li><a class="reference" href="#exception-classes">Exception classes</a></li>
</ul>
<div class="section" id="the-clonable-concept_">
<h1><a name="the-clonable-concept">The Clonable concept</a></h1>
<p><strong>Refinement of</strong></p>
<ul class="simple">
<li>Copy Constructible</li>
<li>Heap Allocable</li>
<li>Heap Deallocable</li>
</ul>
<p>The Clonable concept is introduced to formalize the requirements for
copying heap-allocated objects. A type <tt class="docutils literal"><span class="pre">T</span></tt> might be Clonable even though it
is not Assignable or Copy Constructible. Notice that many operations on
the containers does not even require the stored type to be Clonable.</p>
<p><strong>Notation</strong></p>
<table border="1" class="docutils">
<colgroup>
<col width="21%" />
<col width="41%" />
<col width="18%" />
<col width="20%" />
</colgroup>
<tbody valign="top">
<tr><td><strong>Type</strong></td>
<td><strong>Object</strong> (<tt class="docutils literal"><span class="pre">const</span></tt> or non-<tt class="docutils literal"><span class="pre">const</span></tt>)</td>
<td><strong>Pointer</strong></td>
<td><strong>Describes</strong></td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">T</span></tt></td>
<td><tt class="docutils literal"><span class="pre">a</span></tt></td>
<td><tt class="docutils literal"><span class="pre">ptr</span></tt></td>
<td>A Clonable type</td>
</tr>
</tbody>
</table>
<p><strong>Valid expressions</strong></p>
<table border="1" class="docutils">
<colgroup>
<col width="24%" />
<col width="18%" />
<col width="58%" />
</colgroup>
<tbody valign="top">
<tr><td><strong>Expression</strong></td>
<td><strong>Type</strong></td>
<td><strong>Semantics</strong></td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">new_clone(a);</span></tt></td>
<td><tt class="docutils literal"><span class="pre">T*</span></tt></td>
<td>Allocate a new object that can be considered equivalent to the <tt class="docutils literal"><span class="pre">a</span></tt> object</td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">delete_clone(ptr);</span></tt></td>
<td><tt class="docutils literal"><span class="pre">void</span></tt></td>
<td>Deallocate an object previously allocated with <tt class="docutils literal"><span class="pre">allocate_clone()</span></tt>. Must not throw</td>
</tr>
</tbody>
</table>
<div class="section" id="default-implementation">
<h2><a name="default-implementation">Default implementation</a></h2>
<p>In the <tt class="docutils literal"><span class="pre">&lt;boost/ptr_container/clone_allocator.hpp&gt;</span></tt> header a default implementation
of the two functions is given:</p>
<pre class="literal-block">
namespace boost
{
template&lt; class T &gt;
inline T* new_clone( const T&amp; t )
{
return new T( t );
}
template&lt; class T &gt;
void delete_clone( const T* t )
{
checked_delete( r );
}
}
</pre>
<p>Notice that this implementation makes normal Copy Constructible classes are automatically
Clonable unless <tt class="docutils literal"><span class="pre">operator</span> <span class="pre">new()</span></tt> or <tt class="docutils literal"><span class="pre">operator</span> <span class="pre">delete()</span></tt> are hidden.</p>
<p>The two functions represent a layer of indirection which is necessary to support
classes that are not Copy Constructible by default. Notice that the implementation
relies on argument-dependent lookup (ADL) to find the right version of
<tt class="docutils literal"><span class="pre">new_clone()</span></tt> and <tt class="docutils literal"><span class="pre">delete_clone()</span></tt>. This means that one does not need to overload or specialize
the function is the boost namespace, but it can be placed together with
the rest of the interface of the class. If you are implementing a class
inline in headers, remember to forward declare the functions.</p>
</div>
</div>
<div class="section" id="the-clone-allocator-concept">
<h1><a name="the-clone-allocator-concept">The Clone Allocator concept</a></h1>
<p>The Clone Allocator concept is introduced to formalize the way
pointer containers controls memory of
the stored objects (and not the pointers to the stored objects).
The clone allocator allows
users to apply custom allocators/deallocators for the cloned objects.</p>
<p>More information can be found below:</p>
<div class="contents topic" id="contents">
<ul class="simple">
<li><a class="reference" href="#clone-allocator-requirements" id="id14" name="id14">Clone Allocator requirements</a></li>
<li><a class="reference" href="#class-heap-clone-allocator" id="id15" name="id15">Class <tt class="docutils literal"><span class="pre">heap_clone_allocator</span></tt></a></li>
<li><a class="reference" href="#class-view-clone-allocator" id="id16" name="id16">Class <tt class="docutils literal"><span class="pre">view_clone_allocator</span></tt></a></li>
</ul>
</div>
<div class="section" id="clone-allocator-requirements">
<h2><a class="toc-backref" href="#id14" name="clone-allocator-requirements">Clone Allocator requirements</a></h2>
<p><strong>Notation</strong></p>
<table border="1" class="docutils">
<colgroup>
<col width="18%" />
<col width="39%" />
<col width="43%" />
</colgroup>
<tbody valign="top">
<tr><td><strong>Type</strong></td>
<td><strong>Object</strong> (<tt class="docutils literal"><span class="pre">const</span></tt> or non-<tt class="docutils literal"><span class="pre">const</span></tt>)</td>
<td><strong>Describes</strong></td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">T</span></tt></td>
<td><tt class="docutils literal"><span class="pre">a</span></tt></td>
<td>A type</td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">T*</span></tt></td>
<td><tt class="docutils literal"><span class="pre">ptr</span></tt></td>
<td>A pointer to <tt class="docutils literal"><span class="pre">T</span></tt></td>
</tr>
</tbody>
</table>
<p><strong>Valid expressions</strong></p>
<table border="1" class="docutils">
<colgroup>
<col width="25%" />
<col width="6%" />
<col width="69%" />
</colgroup>
<tbody valign="top">
<tr><td><strong>Expression</strong></td>
<td><strong>Type</strong></td>
<td><strong>Semantics</strong></td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">CloneAllocator::allocate_clone(a);</span></tt></td>
<td><tt class="docutils literal"><span class="pre">T*</span></tt></td>
<td>Allocate a new object that can be considered equivalent to the <tt class="docutils literal"><span class="pre">a</span></tt> object</td>
</tr>
<tr><td><tt class="docutils literal"><span class="pre">CloneAllocator::deallocate_clone(ptr);</span></tt></td>
<td><tt class="docutils literal"><span class="pre">void</span></tt></td>
<td>Deallocate an object previously allocated with <tt class="docutils literal"><span class="pre">CloneAllocator::allocate_clone()</span></tt> or a compatible allocator. Must not throw.</td>
</tr>
</tbody>
</table>
<p>The library comes with two predefined clone allocators.</p>
</div>
<div class="section" id="class-heap-clone-allocator">
<h2><a class="toc-backref" href="#id15" name="class-heap-clone-allocator">Class <tt class="docutils literal"><span class="pre">heap_clone_allocator</span></tt></a></h2>
<p>This is the default clone allocator used by all pointer containers. For most
purposes you will never have to change this default.</p>
<p><strong>Definition</strong></p>
<pre class="literal-block">
namespace boost
{
struct heap_clone_allocator
{
template&lt; class U &gt;
static U* allocate_clone( const U&amp; r )
{
return new_clone( r );
}
template&lt; class U &gt;
static void deallocate_clone( const U* r ) const
{
delete_clone( r );
}
};
}
</pre>
<p>Notice that the above definition allows you to support custom allocation
schemes by relying on <tt class="docutils literal"><span class="pre">new_clone()</span></tt> and <tt class="docutils literal"><span class="pre">delete_clone()</span></tt>.</p>
</div>
<div class="section" id="class-view-clone-allocator">
<h2><a class="toc-backref" href="#id16" name="class-view-clone-allocator">Class <tt class="docutils literal"><span class="pre">view_clone_allocator</span></tt></a></h2>
<p>This class provides a way to remove ownership properties of the
pointer containers. As its name implies, this means that you can
instead use the pointer containers as a view into an existing
container.</p>
<p><strong>Definition</strong></p>
<pre class="literal-block">
namespace boost
{
struct view_clone_allocator
{
template&lt; class U &gt;
static U* allocate_clone( const U&amp; r )
{
return const_cast&lt;U*&gt;(&amp;r);
}
template&lt; class U &gt;
static void deallocate_clone( const U* )
{
// empty
}
};
}
</pre>
<p><strong>See also</strong></p>
<ul class="simple">
<li><a class="reference" href="examples.html#changing-the-clone-allocator">Changing the clone allocator</a></li>
</ul>
</div>
</div>
<div class="section" id="pointer-container-adapters">
<h1><a name="pointer-container-adapters">Pointer container adapters</a></h1>
<p>The pointer container adapters are used when you
want to make a pointer container starting from
your own &quot;normal&quot; container. For example, you
might have a map class that is extends <tt class="docutils literal"><span class="pre">std::map</span></tt>
in some way; the adapter class then allows you
to use your map class as a basis for a new
pointer container.</p>
<p>The library provides an adapter for each type
of standard container:</p>
<ul class="simple">
<li><a class="reference" href="ptr_sequence_adapter.html">ptr_sequence_adapter</a></li>
<li><a class="reference" href="ptr_set_adapter.html">ptr_set_adapter</a></li>
<li><a class="reference" href="ptr_multiset_adapter.html">ptr_multiset_adapter</a></li>
<li><a class="reference" href="ptr_map_adapter.html">ptr_map_adapter</a></li>
<li><a class="reference" href="ptr_multimap_adapter.html">ptr_multimap_adapter</a></li>
</ul>
</div>
<div class="section" id="pointer-containers">
<h1><a name="pointer-containers">Pointer containers</a></h1>
<p>The pointer containers of this library are all built using
the <a class="reference" href="#pointer-container-adapters">pointer container adapters</a>. There is a pointer container
for each type of &quot;normal&quot; standard container:</p>
<div class="section" id="sequence-containers">
<h2><a name="sequence-containers">Sequence containers</a></h2>
<blockquote>
<ul class="simple">
<li><a class="reference" href="ptr_vector.html">ptr_vector</a></li>
<li><a class="reference" href="ptr_deque.html">ptr_deque</a></li>
<li><a class="reference" href="ptr_list.html">ptr_list</a></li>
<li><a class="reference" href="ptr_array.html">ptr_array</a></li>
</ul>
</blockquote>
</div>
<div class="section" id="associative-containers">
<h2><a name="associative-containers">Associative containers</a></h2>
<blockquote>
<ul class="simple">
<li><a class="reference" href="ptr_set.html">ptr_set</a></li>
<li><a class="reference" href="ptr_multiset.html">ptr_multiset</a></li>
<li><a class="reference" href="ptr_map.html">ptr_map</a></li>
<li><a class="reference" href="ptr_multimap.html">ptr_multimap</a></li>
</ul>
</blockquote>
</div>
</div>
<div class="section" id="map-iterator-operations">
<h1><a name="map-iterator-operations">Map iterator operations</a></h1>
<p>The map iterators are a bit different compared to the normal ones. The
reason is that it is a bit clumsy to access the key and the mapped object
through i-&gt;first and i-&gt;second, and one tends to forget what is what.
Moreover, and more importantly, we also want to hide the pointer as much as possibble.
The new style can be illustrated with a small example:</p>
<pre class="literal-block">
typedef ptr_map&lt;string,int&gt; map_t;
map_t m;
m[ &quot;foo&quot; ] = 4; // insert pair
m[ &quot;bar&quot; ] = 5; // ditto
...
for( map_t::iterator i = m.begin(); i != m.end(); ++i )
{
*i += 42; // add 42 to each value
cout &lt;&lt; &quot;value=&quot; &lt;&lt; *i &lt;&lt; &quot;, key=&quot; &lt;&lt; i.key() &lt;&lt; &quot;n&quot;;
}
</pre>
<p>So the difference from the normal map iterator is that</p>
<ul class="simple">
<li><tt class="docutils literal"><span class="pre">operator*()</span></tt> returns a reference to the mapped object (normally it returns a reference to a <tt class="docutils literal"><span class="pre">std::pair</span></tt>, and</li>
<li>that the key can be accessed through the <tt class="docutils literal"><span class="pre">key()</span></tt> function.</li>
</ul>
</div>
<div class="section" id="class-nullable">
<h1><a name="class-nullable">Class <tt class="docutils literal"><span class="pre">nullable</span></tt></a></h1>
<p>The purpose of the class is simply to tell the containers
that null values should be allowed. Its definition is
trivial:</p>
<pre class="literal-block">
namespace boost
{
template&lt; class T &gt;
struct nullable
{
typedef T type;
};
}
</pre>
<p>Please notice that <tt class="docutils literal"><span class="pre">nullable</span></tt> has no effect on the containers
interface (except for <tt class="docutils literal"><span class="pre">is_null()</span></tt> functions). For example, it
does not make sense to do</p>
<pre class="literal-block">
boost::ptr_vector&lt; boost::nullable&lt;T&gt; &gt; vec;
vec.push_back( new boost::nullable&lt;T&gt; ); // no no
boost::nullable&lt;T&gt;&amp; ref = vec[0]; // also no no
</pre>
</div>
<div class="section" id="exception-classes">
<h1><a name="exception-classes">Exception classes</a></h1>
<p>There are three exceptions that are thrown by this library. The exception
hierarchy looks as follows:</p>
<pre class="literal-block">
namespace boost
{
class bad_ptr_container_operation : public std::exception
{
public:
bad_ptr_container_operation( const char* what );
};
class bad_index : public bad_ptr_container_operation
{
public:
bad_index( const char* what );
};
class bad_pointer : public bad_ptr_container_operation
{
public:
bad_pointer();
bad_pointer( const char* what );
};
}
</pre>
<ul class="simple">
<li><a class="reference" href="ptr_container.html">home</a></li>
</ul>
<table class="docutils field-list" frame="void" rules="none">
<col class="field-name" />
<col class="field-body" />
<tbody valign="top">
<tr class="field"><th class="field-name">copyright:</th><td class="field-body">Thorsten Ottosen 2004-2005.</td>
</tr>
</tbody>
</table>
</div>
</div>
</body>
</html>
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