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| <div class="titlepage"><div><div><h2 class="title" style="clear: both"> |
| <a name="intrusive.design_notes"></a><a class="link" href="design_notes.html" title="Design Notes">Design Notes</a> |
| </h2></div></div></div> |
| <div class="toc"><dl> |
| <dt><span class="section"><a href="design_notes.html#intrusive.design_notes.performance_sensitive">Boost.Intrusive |
| in performance sensitive environments</a></span></dt> |
| <dt><span class="section"><a href="design_notes.html#intrusive.design_notes.space_constrained">Boost.Intrusive |
| in space constrained environments</a></span></dt> |
| <dt><span class="section"><a href="design_notes.html#intrusive.design_notes.basic_building_block">Boost.Intrusive |
| as a basic building block</a></span></dt> |
| <dt><span class="section"><a href="design_notes.html#intrusive.design_notes.extending_intrusive">Extending |
| Boost.Intrusive</a></span></dt> |
| </dl></div> |
| <p> |
| When designing <span class="bold"><strong>Boost.Intrusive</strong></span> the following |
| guidelines have been taken into account: |
| </p> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="intrusive.design_notes.performance_sensitive"></a><a class="link" href="design_notes.html#intrusive.design_notes.performance_sensitive" title="Boost.Intrusive in performance sensitive environments">Boost.Intrusive |
| in performance sensitive environments</a> |
| </h3></div></div></div> |
| <p> |
| <span class="bold"><strong>Boost.Intrusive</strong></span> should be a valuable tool |
| in performance sensitive environments, and following this guideline, <span class="bold"><strong>Boost.Intrusive</strong></span> has been designed to offer well known |
| complexity guarantees. Apart from that, some options, like optional constant-time, |
| have been designed to offer faster complexity guarantees in some functions, |
| like <code class="computeroutput"><span class="identifier">slist</span><span class="special">::</span><span class="identifier">splice</span></code>. |
| </p> |
| <p> |
| The advanced lookup and insertion functions for associative containers, taking |
| an arbitrary key type and predicates, were designed to avoid unnecessary |
| object constructions. |
| </p> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="intrusive.design_notes.space_constrained"></a><a class="link" href="design_notes.html#intrusive.design_notes.space_constrained" title="Boost.Intrusive in space constrained environments">Boost.Intrusive |
| in space constrained environments</a> |
| </h3></div></div></div> |
| <p> |
| <span class="bold"><strong>Boost.Intrusive</strong></span> should be useful in space |
| constrained environments, and following this guideline <span class="bold"><strong>Boost.Intrusive</strong></span> |
| separates node algorithms and intrusive containers to avoid instantiating |
| node algorithms for each user type. For example, a single class of red-black |
| algorithms will be instantiated to implement all set and multiset containers |
| using raw pointers. This way, <span class="bold"><strong>Boost.Intrusive</strong></span> |
| seeks to avoid any code size overhead associated with templates. |
| </p> |
| <p> |
| Apart from that, <span class="bold"><strong>Boost.Intrusive</strong></span> implements |
| some size improvements: for example, red-black trees embed the color bit |
| in the parent pointer lower bit, if nodes are two-byte aligned. The option |
| to forgo constant-time size operations can reduce container size, and this |
| extra size optimization is noticeable when the container is empty or contains |
| few values. |
| </p> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="intrusive.design_notes.basic_building_block"></a><a class="link" href="design_notes.html#intrusive.design_notes.basic_building_block" title="Boost.Intrusive as a basic building block">Boost.Intrusive |
| as a basic building block</a> |
| </h3></div></div></div> |
| <p> |
| <span class="bold"><strong>Boost.Intrusive</strong></span> can be a basic building |
| block to build more complex containers and this potential has motivated many |
| design decisions. For example, the ability to have more than one hook per |
| user type opens the opportunity to implement multi-index containers on top |
| of <span class="bold"><strong>Boost.Intrusive</strong></span>. |
| </p> |
| <p> |
| <span class="bold"><strong>Boost.Intrusive</strong></span> containers implement advanced |
| functions taking function objects as arguments (<code class="computeroutput"><span class="identifier">clone_from</span></code>, |
| <code class="computeroutput"><span class="identifier">erase_and_dispose</span></code>, <code class="computeroutput"><span class="identifier">insert_check</span></code>, etc.). These functions come |
| in handy when implementing non-intrusive containers (for example, STL-like |
| containers) on top of intrusive containers. |
| </p> |
| </div> |
| <div class="section"> |
| <div class="titlepage"><div><div><h3 class="title"> |
| <a name="intrusive.design_notes.extending_intrusive"></a><a class="link" href="design_notes.html#intrusive.design_notes.extending_intrusive" title="Extending Boost.Intrusive">Extending |
| Boost.Intrusive</a> |
| </h3></div></div></div> |
| <p> |
| <span class="bold"><strong>Boost.Intrusive</strong></span> offers a wide range of containers |
| but also allows the construction of custom containers reusing <span class="bold"><strong>Boost.Intrusive</strong></span> |
| elements. The programmer might want to use node algorithms directly or build |
| special hooks that take advantage of an application environment. |
| </p> |
| <p> |
| For example, the programmer can customize parts of <span class="bold"><strong>Boost.Intrusive</strong></span> |
| to manage old data structures whose definition can't be changed. |
| </p> |
| </div> |
| </div> |
| <table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> |
| <td align="left"></td> |
| <td align="right"><div class="copyright-footer">Copyright © 2005 Olaf Krzikalla, 2006-2010 Ion Gaztanaga<p> |
| Distributed under the Boost Software License, Version 1.0. (See accompanying |
| file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>) |
| </p> |
| </div></td> |
| </tr></table> |
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