| <?xml version="1.0" encoding="utf-8" ?> |
| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> |
| <html xmlns="http://www.w3.org/1999/xhtml" xml:lang="en" lang="en"> |
| <head> |
| <meta http-equiv="Content-Type" content="text/html; charset=utf-8" /> |
| <meta name="generator" content="Docutils 0.3.10: http://docutils.sourceforge.net/" /> |
| <title>Boost Pointer Container Library</title> |
| <style type="text/css"> |
| |
| /* |
| :Author: David Goodger |
| :Contact: goodger@users.sourceforge.net |
| :Date: $Date: 2006-11-22 17:01:03 -0500 (Wed, 22 Nov 2006) $ |
| :Revision: $Revision: 36152 $ |
| :Copyright: This stylesheet has been placed in the public domain. |
| |
| Default cascading style sheet for the HTML output of Docutils. |
| |
| See http://docutils.sf.net/docs/howto/html-stylesheets.html for how to |
| customize this style sheet. |
| */ |
| |
| /* "! important" is used here to override other ``margin-top`` and |
| ``margin-bottom`` styles that are later in the stylesheet or |
| more specific. See http://www.w3.org/TR/CSS1#the-cascade */ |
| .first { |
| margin-top: 0 ! important } |
| |
| .last, .with-subtitle { |
| margin-bottom: 0 ! important } |
| |
| .hidden { |
| display: none } |
| |
| a.toc-backref { |
| text-decoration: none ; |
| color: black } |
| |
| blockquote.epigraph { |
| margin: 2em 5em ; } |
| |
| dl.docutils dd { |
| margin-bottom: 0.5em } |
| |
| /* Uncomment (and remove this text!) to get bold-faced definition list terms |
| dl.docutils dt { |
| font-weight: bold } |
| */ |
| |
| div.abstract { |
| margin: 2em 5em } |
| |
| div.abstract p.topic-title { |
| font-weight: bold ; |
| text-align: center } |
| |
| div.admonition, div.attention, div.caution, div.danger, div.error, |
| div.hint, div.important, div.note, div.tip, div.warning { |
| margin: 2em ; |
| border: medium outset ; |
| padding: 1em } |
| |
| div.admonition p.admonition-title, div.hint p.admonition-title, |
| div.important p.admonition-title, div.note p.admonition-title, |
| div.tip p.admonition-title { |
| font-weight: bold ; |
| font-family: sans-serif } |
| |
| div.attention p.admonition-title, div.caution p.admonition-title, |
| div.danger p.admonition-title, div.error p.admonition-title, |
| div.warning p.admonition-title { |
| color: red ; |
| font-weight: bold ; |
| font-family: sans-serif } |
| |
| /* Uncomment (and remove this text!) to get reduced vertical space in |
| compound paragraphs. |
| div.compound .compound-first, div.compound .compound-middle { |
| margin-bottom: 0.5em } |
| |
| div.compound .compound-last, div.compound .compound-middle { |
| margin-top: 0.5em } |
| */ |
| |
| div.dedication { |
| margin: 2em 5em ; |
| text-align: center ; |
| font-style: italic } |
| |
| div.dedication p.topic-title { |
| font-weight: bold ; |
| font-style: normal } |
| |
| div.figure { |
| margin-left: 2em } |
| |
| div.footer, div.header { |
| clear: both; |
| font-size: smaller } |
| |
| div.line-block { |
| display: block ; |
| margin-top: 1em ; |
| margin-bottom: 1em } |
| |
| div.line-block div.line-block { |
| margin-top: 0 ; |
| margin-bottom: 0 ; |
| margin-left: 1.5em } |
| |
| div.sidebar { |
| margin-left: 1em ; |
| border: medium outset ; |
| padding: 1em ; |
| background-color: #ffffee ; |
| width: 40% ; |
| float: right ; |
| clear: right } |
| |
| div.sidebar p.rubric { |
| font-family: sans-serif ; |
| font-size: medium } |
| |
| div.system-messages { |
| margin: 5em } |
| |
| div.system-messages h1 { |
| color: red } |
| |
| div.system-message { |
| border: medium outset ; |
| padding: 1em } |
| |
| div.system-message p.system-message-title { |
| color: red ; |
| font-weight: bold } |
| |
| div.topic { |
| margin: 2em } |
| |
| h1.section-subtitle, h2.section-subtitle, h3.section-subtitle, |
| h4.section-subtitle, h5.section-subtitle, h6.section-subtitle { |
| margin-top: 0.4em } |
| |
| h1.title { |
| text-align: center } |
| |
| h2.subtitle { |
| text-align: center } |
| |
| hr.docutils { |
| width: 75% } |
| |
| img.align-left { |
| clear: left } |
| |
| img.align-right { |
| clear: right } |
| |
| img.borderless { |
| border: 0 } |
| |
| ol.simple, ul.simple { |
| margin-bottom: 1em } |
| |
| ol.arabic { |
| list-style: decimal } |
| |
| ol.loweralpha { |
| list-style: lower-alpha } |
| |
| ol.upperalpha { |
| list-style: upper-alpha } |
| |
| ol.lowerroman { |
| list-style: lower-roman } |
| |
| ol.upperroman { |
| list-style: upper-roman } |
| |
| p.attribution { |
| text-align: right ; |
| margin-left: 50% } |
| |
| p.caption { |
| font-style: italic } |
| |
| p.credits { |
| font-style: italic ; |
| font-size: smaller } |
| |
| p.label { |
| white-space: nowrap } |
| |
| p.rubric { |
| font-weight: bold ; |
| font-size: larger ; |
| color: maroon ; |
| text-align: center } |
| |
| p.sidebar-title { |
| font-family: sans-serif ; |
| font-weight: bold ; |
| font-size: larger } |
| |
| p.sidebar-subtitle { |
| font-family: sans-serif ; |
| font-weight: bold } |
| |
| p.topic-title { |
| font-weight: bold } |
| |
| pre.address { |
| margin-bottom: 0 ; |
| margin-top: 0 ; |
| font-family: serif ; |
| font-size: 100% } |
| |
| pre.line-block { |
| font-family: serif ; |
| font-size: 100% } |
| |
| pre.literal-block, pre.doctest-block { |
| margin-left: 2em ; |
| margin-right: 2em ; |
| background-color: #eeeeee } |
| |
| span.classifier { |
| font-family: sans-serif ; |
| font-style: oblique } |
| |
| span.classifier-delimiter { |
| font-family: sans-serif ; |
| font-weight: bold } |
| |
| span.interpreted { |
| font-family: sans-serif } |
| |
| span.option { |
| white-space: nowrap } |
| |
| span.pre { |
| white-space: pre } |
| |
| span.problematic { |
| color: red } |
| |
| span.section-subtitle { |
| /* font-size relative to parent (h1..h6 element) */ |
| font-size: 80% } |
| |
| table.citation { |
| border-left: solid thin gray } |
| |
| table.docinfo { |
| margin: 2em 4em } |
| |
| table.docutils { |
| margin-top: 0.5em ; |
| margin-bottom: 0.5em } |
| |
| table.footnote { |
| border-left: solid thin black } |
| |
| table.docutils td, table.docutils th, |
| table.docinfo td, table.docinfo th { |
| padding-left: 0.5em ; |
| padding-right: 0.5em ; |
| vertical-align: top } |
| |
| table.docutils th.field-name, table.docinfo th.docinfo-name { |
| font-weight: bold ; |
| text-align: left ; |
| white-space: nowrap ; |
| padding-left: 0 } |
| |
| h1 tt.docutils, h2 tt.docutils, h3 tt.docutils, |
| h4 tt.docutils, h5 tt.docutils, h6 tt.docutils { |
| font-size: 100% } |
| |
| tt.docutils { |
| background-color: #eeeeee } |
| |
| ul.auto-toc { |
| list-style-type: none } |
| |
| </style> |
| </head> |
| <body> |
| <div class="document" id="boost-pointer-container-library"> |
| <h1 class="title"><img alt="Boost" src="boost.png" /> Pointer Container Library</h1> |
| <h2 class="subtitle" id="indirected-functions">Indirected functions</h2> |
| <p>It is quite common that we have two pointers and what to compare the |
| pointed to objects. Also, we have usually already defined how |
| to compare the objects. So to avoid some tedious boiler-plate code |
| this library defines predicates that apply an indirection before comparing.</p> |
| <p>When the container uses <tt class="docutils literal"><span class="pre">void*</span></tt> internally, we can use the |
| class <tt class="docutils literal"><span class="pre">void_ptr_indirect_fun</span></tt>; otherwise we use the class |
| <tt class="docutils literal"><span class="pre">indirect_fun</span></tt>.</p> |
| <p><strong>Example:</strong></p> |
| <pre class="literal-block"> |
| std::string* bar = new std::string("bar"); |
| std::string* foo = new std::string("foo"); |
| BOOST_ASSERT( indirect_fun< std::less<std::string> >()( bar, foo ) == true ); |
| BOOST_ASSERT( make_indirect_fun( std::less<std::string>() )( foo, bar ) == false ); |
| |
| void* vptr1 = ptr1; |
| void* vptr2 = ptr2; |
| void_ptr_indirect_fun< std::less<std::string>, std::string> cast_fun; |
| BOOST_CHECK( cast_fun( vptr1, vptr2 ) == true ); |
| </pre> |
| <p><strong>See also:</strong></p> |
| <ul class="simple"> |
| <li><a class="reference" href="http://www.boost.org/libs/utility/utility.htm#result_of">result_of</a></li> |
| <li><a class="reference" href="http://www.boost.org/libs/iterator/doc/pointee.html">pointee</a></li> |
| <li><a class="reference" href="ptr_set.html">ptr_set</a></li> |
| <li><a class="reference" href="ptr_multiset.html">ptr_multiset</a></li> |
| </ul> |
| <p><strong>Navigate</strong></p> |
| <ul class="simple"> |
| <li><a class="reference" href="ptr_container.html">home</a></li> |
| <li><a class="reference" href="reference.html">reference</a></li> |
| </ul> |
| <p><strong>Remarks:</strong></p> |
| <p>The class <tt class="docutils literal"><span class="pre">indirect_fun</span></tt> will work with smart pointers such as <a class="reference" href="http://www.boost.org/libs/smart_ptr/shared_ptr.htm">boost::shared_ptr<T></a> |
| because of the type traits <tt class="docutils literal"><span class="pre">pointee<T>::type</span></tt> from the header <tt class="docutils literal"><span class="pre"><boost/pointee.hpp></span></tt>.</p> |
| <p><strong>Synopsis:</strong></p> |
| <p>Since the definition of the predicates is somewhat trivial, only the |
| first operation is expanded inline.</p> |
| <pre class="literal-block"> |
| namespace boost |
| { |
| |
| template< class Fun > |
| struct indirect_fun |
| { |
| indirect_fun() : fun(Fun()) |
| { } |
| |
| indirect_fun( Fun f ) : fun(f) |
| { } |
| |
| template< class T > |
| typename result_of< Fun( typename pointee<T>::type ) >::type |
| operator()( const T& r ) const |
| { |
| return fun( *r ); |
| } |
| |
| template< class T, class U > |
| typename result_of< Fun( typename pointee<T>::type, |
| typename pointee<U>::type ) >::type |
| operator()( const T& r, const U& r2 ) const |
| { |
| return fun( *r, *r2 ); |
| } |
| |
| private: |
| Fun fun; |
| }; |
| |
| template< class Fun > |
| inline indirect_fun<Fun> make_indirect_fun( Fun f ) |
| { |
| return indirect_fun<Fun>( f ); |
| } |
| |
| |
| |
| template< class Fun, class Arg1, class Arg2 = Arg1 > |
| struct void_ptr_indirect_fun |
| { |
| void_ptr_indirect_fun() : fun(Fun()) |
| { } |
| |
| void_ptr_indirect_fun( Fun f ) : fun(f) |
| { } |
| |
| typename result_of< Fun( Arg1 ) >::type |
| operator()( const void* r ) const |
| { |
| return fun( * static_cast<const Arg1*>( r ) ); |
| } |
| |
| typename result_of< Fun( Arg1, Arg2 ) >::type |
| operator()( const void* l, const void* r ) const |
| { |
| return fun( * static_cast<const Arg1*>( l ), * static_cast<const Arg2*>( r ) ); |
| } |
| |
| private: |
| Fun fun; |
| }; |
| |
| template< class Fun, class Arg > |
| inline void_ptr_indirect_fun<Fun,Arg> |
| make_void_ptr_indirect_fun( Fun f ) |
| { |
| return void_ptr_indirect_fun<Fun,Arg>( f ); |
| } |
| |
| } // namespace 'boost' |
| </pre> |
| <hr><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 2004-2006. Use, modification and distribution is subject to the Boost Software License, Version 1.0 (see <a class="reference" href="http://www.boost.org/LICENSE_1_0.txt">LICENSE_1_0.txt</a>).</td> |
| </tr> |
| </tbody> |
| </table> |
| </div> |
| </body> |
| </html> |