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- <h1><img src="../../../../boost.png" alt="boost.png (6897 bytes)" align=
- "middle" width="277" height="86">Boost.MultiIndex Hashed indices reference</h1>
- <div class="prev_link"><a href="rnk_indices.html"><img src="../prev.gif" alt="ranked indices" border="0"><br>
- Ranked indices
- </a></div>
- <div class="up_link"><a href="index.html"><img src="../up.gif" alt="Boost.MultiIndex reference" border="0"><br>
- Boost.MultiIndex reference
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- Sequenced indices
- </a></div><br clear="all" style="clear: all;">
- <hr>
- <h2>Contents</h2>
- <ul>
- <li><a href="#hash_index_fwd_synopsis">Header
- <code>"boost/multi_index/hashed_index_fwd.hpp"</code> synopsis</a></li>
- <li><a href="#synopsis">Header
- <code>"boost/multi_index/hashed_index.hpp"</code> synopsis</a>
- <ul>
- <li><a href="#unique_non_unique">
- Index specifiers <code>hashed_unique</code> and <code>hashed_non_unique</code>
- </a></li>
- <li><a href="#hash_indices">Hashed indices</a>
- <ul>
- <li><a href="#complexity_signature">Complexity signature</a></li>
- <li><a href="#instantiation_types">Instantiation types</a></li>
- <li><a href="#types">Nested types</a></li>
- <li><a href="#constructors">Constructors, copy and assignment</a></li>
- <li><a href="#iterators">Iterators</a></li>
- <li><a href="#modifiers">Modifiers</a></li>
- <li><a href="#observers">Observers</a></li>
- <li><a href="#lookup">Lookup</a></li>
- <li><a href="#bucket_interface">Bucket interface</a></li>
- <li><a href="#hash_policy">Hash policy</a></li>
- <li><a href="#comparison">Comparison</a></li>
- <li><a href="#serialization">Serialization</a></li>
- </ul>
- </li>
- </ul>
- </li>
- </ul>
- <h2>
- <a name="hash_index_fwd_synopsis">Header
- <a href="../../../../boost/multi_index/hashed_index_fwd.hpp">
- <code>"boost/multi_index/hashed_index_fwd.hpp"</code></a> synopsis</a></h2>
- <blockquote><pre>
- <span class=keyword>namespace</span> <span class=identifier>boost</span><span class=special>{</span>
- <span class=keyword>namespace</span> <span class=identifier>multi_index</span><span class=special>{</span>
- <span class=comment>// index specifiers hashed_unique and hashed_non_unique</span>
- <span class=keyword>template</span><span class=special><</span><b>consult hashed_unique reference for arguments</b><span class=special>></span>
- <span class=keyword>struct</span> <span class=identifier>hashed_unique</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span><b>consult hashed_non_unique reference for arguments</b><span class=special>></span>
- <span class=keyword>struct</span> <span class=identifier>hashed_non_unique</span><span class=special>;</span>
- <span class=comment>// indices</span>
- <span class=keyword>namespace</span> <span class=identifier>detail</span><span class=special>{</span>
- <span class=keyword>template</span><span class=special><</span><b>implementation defined</b><span class=special>></span> <span class=keyword>class</span> <b>index name is implementation defined</b><span class=special>;</span>
- <span class=special>}</span> <span class=comment>// namespace boost::multi_index::detail</span>
- <span class=special>}</span> <span class=comment>// namespace boost::multi_index</span>
- <span class=special>}</span> <span class=comment>// namespace boost</span>
- </pre></blockquote>
- <p>
- <code>hashed_index_fwd.hpp</code> provides forward declarations for index specifiers
- <a href="#unique_non_unique"><code>hashed_unique</code> and <code>hashed_non_unique</code></a> and
- their associated <a href="#hash_indices">hashed index</a> classes.
- </p>
- <h2>
- <a name="synopsis">Header
- <a href="../../../../boost/multi_index/hashed_index.hpp">
- <code>"boost/multi_index/hashed_index.hpp"</code></a> synopsis</a></h2>
- <blockquote><pre>
- <span class=preprocessor>#include</span> <span class=special><</span><span class=identifier>initializer_list</span><span class=special>></span>
- <span class=keyword>namespace</span> <span class=identifier>boost</span><span class=special>{</span>
- <span class=keyword>namespace</span> <span class=identifier>multi_index</span><span class=special>{</span>
- <span class=comment>// index specifiers hashed_unique and hashed_non_unique</span>
- <span class=keyword>template</span><span class=special><</span><b>consult hashed_unique reference for arguments</b><span class=special>></span>
- <span class=keyword>struct</span> <span class=identifier>hashed_unique</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span><b>consult hashed_non_unique reference for arguments</b><span class=special>></span>
- <span class=keyword>struct</span> <span class=identifier>hashed_non_unique</span><span class=special>;</span>
- <span class=comment>// indices</span>
- <span class=keyword>namespace</span> <span class=identifier>detail</span><span class=special>{</span>
- <span class=keyword>template</span><span class=special><</span><b>implementation defined</b><span class=special>></span> <span class=keyword>class</span> <b>index class name implementation defined</b><span class=special>;</span>
- <span class=comment>// index comparison:</span>
- <span class=comment>// <b>OP</b> is any of ==,!=</span>
- <span class=keyword>template</span><span class=special><</span><b>implementation defined</b><span class=special>></span>
- <span class=keyword>bool</span> <span class=keyword>operator</span> <b><i>OP</i></b><span class=special>(</span><span class=keyword>const</span> <b>index class name</b><span class=special>&</span> <span class=identifier>x</span><span class=special>,</span><span class=keyword>const</span> <b>index class name</b><span class=special>&</span> <span class=identifier>y</span><span class=special>);</span>
- <span class=comment>// index specialized algorithms:</span>
- <span class=keyword>template</span><span class=special><</span><b>implementation defined</b><span class=special>></span>
- <span class=keyword>void</span> <span class=identifier>swap</span><span class=special>(</span><b>index class name</b><span class=special>&</span> <span class=identifier>x</span><span class=special>,</span><b>index class name</b><span class=special>&</span> <span class=identifier>y</span><span class=special>);</span>
- <span class=special>}</span> <span class=comment>// namespace boost::multi_index::detail</span>
- <span class=special>}</span> <span class=comment>// namespace boost::multi_index</span>
- <span class=special>}</span> <span class=comment>// namespace boost</span>
- </pre></blockquote>
- <h3><a name="unique_non_unique">
- Index specifiers <code>hashed_unique</code> and <code>hashed_non_unique</code>
- </a></h3>
- <p>
- These <a href="indices.html#index_specification">index specifiers</a> allow
- for insertion of <a href="#hash_indices">hashed indices</a> without and with
- allowance of duplicate elements, respectively. The syntax of <code>hashed_unique</code>
- and <code>hashed_non_unique</code> coincide, thus we describe them in a grouped manner.
- <code>hashed_unique</code> and <code>hashed_non_unique</code> can be instantiated in
- two different forms, according to whether a tag list for the index is provided or not:
- </p>
- <blockquote><pre>
- <span class=keyword>template</span><span class=special><</span>
- <span class=keyword>typename</span> <span class=identifier>KeyFromValue</span><span class=special>,</span>
- <span class=keyword>typename</span> <span class=identifier>Hash</span><span class=special>=</span><span class=identifier>boost</span><span class=special>::</span><span class=identifier>hash</span><span class=special><</span><span class=identifier>KeyFromValue</span><span class=special>::</span><span class=identifier>result_type</span><span class=special>>,</span>
- <span class=keyword>typename</span> <span class=identifier>Pred</span><span class=special>=</span><span class=identifier>std</span><span class=special>::</span><span class=identifier>equal_to</span><span class=special><</span><span class=identifier>KeyFromValue</span><span class=special>::</span><span class=identifier>result_type</span><span class=special>></span>
- <span class=special>></span>
- <span class=keyword>struct</span> <span class=special>(</span><span class=identifier>hashed_unique</span> <span class=special>|</span> <span class=identifier>hashed_non_unique</span><span class=special>)</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span>
- <span class=keyword>typename</span> <span class=identifier>TagList</span><span class=special>,</span>
- <span class=keyword>typename</span> <span class=identifier>KeyFromValue</span><span class=special>,</span>
- <span class=keyword>typename</span> <span class=identifier>Hash</span><span class=special>=</span><span class=identifier>boost</span><span class=special>::</span><span class=identifier>hash</span><span class=special><</span><span class=identifier>KeyFromValue</span><span class=special>::</span><span class=identifier>result_type</span><span class=special>>,</span>
- <span class=keyword>typename</span> <span class=identifier>Pred</span><span class=special>=</span><span class=identifier>std</span><span class=special>::</span><span class=identifier>equal_to</span><span class=special><</span><span class=identifier>KeyFromValue</span><span class=special>::</span><span class=identifier>result_type</span><span class=special>></span>
- <span class=special>></span>
- <span class=keyword>struct</span> <span class=special>(</span><span class=identifier>hashed_unique</span> <span class=special>|</span> <span class=identifier>hashed_non_unique</span><span class=special>)</span><span class=special>;</span>
- </pre></blockquote>
- <p>
- If provided, <code>TagList</code> must be an instantiation of the class template
- <a href="indices.html#tag"><code>tag</code></a>.
- The template arguments are used by the corresponding index implementation,
- refer to the <a href="#hash_indices">hashed indices</a> reference section for further
- explanations on their acceptable type values.
- </p>
- <h3><a name="hash_indices">Hashed indices</a></h3>
- <p>
- A hashed index provides fast retrieval of elements of a <code>multi_index_container</code>
- through hashing techniques.
- A hashed index is particularized according to a given
- <a href="key_extraction.html#key_extractors"><code>Key Extractor</code></a>
- that retrieves keys from elements of <code>multi_index_container</code>, a <code>Hash</code>
- function object which returns hash values for the keys and a binary predicate <code>Pred</code>
- acting as an equivalence relation on values of <code>Key</code>.
- </p>
- <p>
- There are two variants of hashed indices: <i>unique</i>, which do
- not allow duplicate elements (with respect to its associated equality
- predicate) and <i>non-unique</i>, which accept those duplicates.
- The interface of these two variants is the same, so they are documented
- together, with minor differences explicitly stated when they exist.
- </p>
- <p>
- Except where noted or if the corresponding interface does not exist, hashed indices
- (both unique and non-unique) satisfy the C++ requirements for unordered associative
- containers at <b>[unord.req]</b> (supporting unique and equivalent keys, respectively.)
- Validity of iterators and references to
- elements is preserved in all cases. Occasionally, the exception safety guarantees provided
- are actually stronger than required by the standard. We only provide descriptions of
- those types and operations that do not exactly conform to or are not mandated by the standard
- requirements.
- </p>
- <blockquote><pre>
- <span class=keyword>namespace</span> <span class=identifier>boost</span><span class=special>{</span>
- <span class=keyword>namespace</span> <span class=identifier>multi_index</span><span class=special>{</span>
- <span class=keyword>namespace</span> <span class=identifier>detail</span><span class=special>{</span>
- <span class=keyword>template</span><span class=special><</span><b>implementation defined: dependent on types Value, Allocator,
- TagList, KeyFromValue, Hash, Pred</b><span class=special>></span>
- <span class=keyword>class</span> <b>name is implementation defined</b>
- <span class=special>{</span>
- <span class=keyword>public</span><span class=special>:</span>
- <span class=comment>// types:</span>
- <span class=keyword>typedef</span> <span class=keyword>typename</span> <span class=identifier>KeyFromValue</span><span class=special>::</span><span class=identifier>result_type</span> <span class=identifier>key_type</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=identifier>Value</span> <span class=identifier>value_type</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=identifier>KeyFromValue</span> <span class=identifier>key_from_value</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=identifier>Hash</span> <span class=identifier>hasher</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=identifier>Pred</span> <span class=identifier>key_equal</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=identifier>boost</span><span class=special>::</span><span class=identifier>tuple</span><span class=special><</span>
- <span class=identifier>size_type</span><span class=special>,</span><span class=identifier>key_from_value</span><span class=special>,</span><span class=identifier>hasher</span><span class=special>,</span><span class=identifier>key_equal</span><span class=special>></span> <span class=identifier>ctor_args</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=identifier>TagList</span> <span class=identifier>tag_list</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=identifier>Allocator</span> <span class=identifier>allocator_type</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=keyword>typename</span> <span class=identifier>Allocator</span><span class=special>::</span><span class=identifier>pointer</span> <span class=identifier>pointer</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=keyword>typename</span> <span class=identifier>Allocator</span><span class=special>::</span><span class=identifier>const_pointer</span> <span class=identifier>const_pointer</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=keyword>typename</span> <span class=identifier>Allocator</span><span class=special>::</span><span class=identifier>reference</span> <span class=identifier>reference</span><span class=special>;</span>
- <span class=keyword>typedef</span> <span class=keyword>typename</span> <span class=identifier>Allocator</span><span class=special>::</span><span class=identifier>const_reference</span> <span class=identifier>const_reference</span><span class=special>;</span>
- <span class=keyword>typedef</span> <b>implementation defined </b><span class=identifier>size_type</span><span class=special>;</span>
- <span class=keyword>typedef</span> <b>implementation defined </b><span class=identifier>difference_type</span><span class=special>;</span>
- <span class=keyword>typedef</span> <b>implementation defined </b><span class=identifier>iterator</span><span class=special>;</span>
- <span class=keyword>typedef</span> <b>implementation defined </b><span class=identifier>const_iterator</span><span class=special>;</span>
- <span class=keyword>typedef</span> <b>implementation defined </b><span class=identifier>local_iterator</span><span class=special>;</span>
- <span class=keyword>typedef</span> <b>implementation defined </b><span class=identifier>const_local_iterator</span><span class=special>;</span>
- <span class=comment>// construct/destroy/copy:</span>
- <b>index class name</b><span class=special>&</span> <span class=keyword>operator</span><span class=special>=(</span><span class=keyword>const</span> <b>index class name</b><span class=special>&</span> <span class=identifier>x</span><span class=special>);</span>
- <b>index class name</b><span class=special>&</span> <span class=keyword>operator</span><span class=special>=(</span><span class=identifier>std</span><span class=special>::</span><span class=identifier>initializer_list</span><span class=special><</span><span class=identifier>value_type</span><span class=special>></span> <span class=identifier>list</span><span class=special>);</span>
- <span class=identifier>allocator_type</span> <span class=identifier>get_allocator</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=comment>// size and capacity:</span>
- <span class=keyword>bool</span> <span class=identifier>empty</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=identifier>size_type</span> <span class=identifier>size</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=identifier>size_type</span> <span class=identifier>max_size</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=comment>// iterators:</span>
- <span class=identifier>iterator</span> <span class=identifier>begin</span><span class=special>()</span><span class=keyword>noexcept</span><span class=special>;</span>
- <span class=identifier>const_iterator</span> <span class=identifier>begin</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=identifier>iterator</span> <span class=identifier>end</span><span class=special>()</span><span class=keyword>noexcept</span><span class=special>;</span>
- <span class=identifier>const_iterator</span> <span class=identifier>end</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=identifier>const_iterator</span> <span class=identifier>cbegin</span><span class=special>()</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>const_iterator</span> <span class=identifier>cend</span><span class=special>()</span><span class=keyword>const</span><span class=special>;</span>
-
- <span class=identifier>iterator</span> <span class=identifier>iterator_to</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>value_type</span><span class=special>&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=identifier>const_iterator</span> <span class=identifier>iterator_to</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>value_type</span><span class=special>&</span> <span class=identifier>x</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=comment>// modifiers:</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span><span class=special>...</span> <span class=identifier>Args</span><span class=special>></span>
- <span class=identifier>std</span><span class=special>::</span><span class=identifier>pair</span><span class=special><</span><span class=identifier>iterator</span><span class=special>,</span><span class=keyword>bool</span><span class=special>></span> <span class=identifier>emplace</span><span class=special>(</span><span class=identifier>Args</span><span class=special>&&...</span> <span class=identifier>args</span><span class=special>);</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span><span class=special>...</span> <span class=identifier>Args</span><span class=special>></span>
- <span class=identifier>iterator</span> <span class=identifier>emplace_hint</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=identifier>Args</span><span class=special>&&...</span> <span class=identifier>args</span><span class=special>);</span>
- <span class=identifier>std</span><span class=special>::</span><span class=identifier>pair</span><span class=special><</span><span class=identifier>iterator</span><span class=special>,</span><span class=keyword>bool</span><span class=special>></span> <span class=identifier>insert</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>value_type</span><span class=special>&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=identifier>std</span><span class=special>::</span><span class=identifier>pair</span><span class=special><</span><span class=identifier>iterator</span><span class=special>,</span><span class=keyword>bool</span><span class=special>></span> <span class=identifier>insert</span><span class=special>(</span><span class=identifier>value_type</span><span class=special>&&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=identifier>iterator</span> <span class=identifier>insert</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=keyword>const</span> <span class=identifier>value_type</span><span class=special>&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=identifier>iterator</span> <span class=identifier>insert</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=identifier>value_type</span><span class=special>&&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>InputIterator</span><span class=special>></span>
- <span class=keyword>void</span> <span class=identifier>insert</span><span class=special>(</span><span class=identifier>InputIterator</span> <span class=identifier>first</span><span class=special>,</span><span class=identifier>InputIterator</span> <span class=identifier>last</span><span class=special>);</span>
- <span class=keyword>void</span> <span class=identifier>insert</span><span class=special>(</span><span class=identifier>std</span><span class=special>::</span><span class=identifier>initializer_list</span><span class=special><</span><span class=identifier>value_type</span><span class=special>></span> <span class=identifier>list</span><span class=special>);</span>
- <span class=identifier>iterator</span> <span class=identifier>erase</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>);</span>
- <span class=identifier>size_type</span> <span class=identifier>erase</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>key_type</span><span class=special>&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=identifier>iterator</span> <span class=identifier>erase</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>first</span><span class=special>,</span><span class=identifier>iterator</span> <span class=identifier>last</span><span class=special>);</span>
- <span class=keyword>bool</span> <span class=identifier>replace</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=keyword>const</span> <span class=identifier>value_type</span><span class=special>&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=keyword>bool</span> <span class=identifier>replace</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=identifier>value_type</span><span class=special>&&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>Modifier</span><span class=special>></span> <span class=keyword>bool</span> <span class=identifier>modify</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=identifier>Modifier</span> <span class=identifier>mod</span><span class=special>);</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>Modifier</span><span class=special>,</span><span class=keyword>typename</span> <span class=identifier>Rollback</span><span class=special>></span>
- <span class=keyword>bool</span> <span class=identifier>modify</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=identifier>Modifier</span> <span class=identifier>mod</span><span class=special>,</span><span class=identifier>Rollback</span> <span class=identifier>back</span><span class=special>);</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>Modifier</span><span class=special>></span> <span class=keyword>bool</span> <span class=identifier>modify_key</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=identifier>Modifier</span> <span class=identifier>mod</span><span class=special>);</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>Modifier</span><span class=special>,</span><span class=keyword>typename</span> <span class=identifier>Rollback</span><span class=special>></span>
- <span class=keyword>bool</span> <span class=identifier>modify_key</span><span class=special>(</span><span class=identifier>iterator</span> <span class=identifier>position</span><span class=special>,</span><span class=identifier>Modifier</span> <span class=identifier>mod</span><span class=special>,</span><span class=identifier>Rollback</span> <span class=identifier>back</span><span class=special>);</span>
-
- <span class=keyword>void</span> <span class=identifier>clear</span><span class=special>()</span><span class=keyword>noexcept</span><span class=special>;</span>
- <span class=keyword>void</span> <span class=identifier>swap</span><span class=special>(</span><b>index class name</b><span class=special>&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=comment>// observers:</span>
- <span class=identifier>key_from_value</span> <span class=identifier>key_extractor</span><span class=special>()</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>hasher</span> <span class=identifier>hash_function</span><span class=special>()</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>key_equal</span> <span class=identifier>key_eq</span><span class=special>()</span><span class=keyword>const</span><span class=special>;</span>
- <span class=comment>// lookup:</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>CompatibleKey</span><span class=special>></span>
- <span class=identifier>iterator</span> <span class=identifier>find</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>CompatibleKey</span><span class=special>&</span> <span class=identifier>x</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span>
- <span class=keyword>typename</span> <span class=identifier>CompatibleKey</span><span class=special>,</span><span class=keyword>typename</span> <span class=identifier>CompatibleHash</span><span class=special>,</span> <span class=keyword>typename</span> <span class=identifier>CompatiblePred</span>
- <span class=special>></span>
- <span class=identifier>iterator</span> <span class=identifier>find</span><span class=special>(</span>
- <span class=keyword>const</span> <span class=identifier>CompatibleKey</span><span class=special>&</span> <span class=identifier>x</span><span class=special>,</span>
- <span class=keyword>const</span> <span class=identifier>CompatibleHash</span><span class=special>&</span> <span class=identifier>hash</span><span class=special>,</span><span class=keyword>const</span> <span class=identifier>CompatiblePred</span><span class=special>&</span> <span class=identifier>eq</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>CompatibleKey</span><span class=special>></span>
- <span class=identifier>size_type</span> <span class=identifier>count</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>CompatibleKey</span><span class=special>&</span> <span class=identifier>x</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span>
- <span class=keyword>typename</span> <span class=identifier>CompatibleKey</span><span class=special>,</span><span class=keyword>typename</span> <span class=identifier>CompatibleHash</span><span class=special>,</span> <span class=keyword>typename</span> <span class=identifier>CompatiblePred</span>
- <span class=special>></span>
- <span class=identifier>size_type</span> <span class=identifier>count</span><span class=special>(</span>
- <span class=keyword>const</span> <span class=identifier>CompatibleKey</span><span class=special>&</span> <span class=identifier>x</span><span class=special>,</span>
- <span class=keyword>const</span> <span class=identifier>CompatibleHash</span><span class=special>&</span> <span class=identifier>hash</span><span class=special>,</span><span class=keyword>const</span> <span class=identifier>CompatiblePred</span><span class=special>&</span> <span class=identifier>eq</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span><span class=keyword>typename</span> <span class=identifier>CompatibleKey</span><span class=special>></span>
- <span class=identifier>std</span><span class=special>::</span><span class=identifier>pair</span><span class=special><</span><span class=identifier>iterator</span><span class=special>,</span><span class=identifier>iterator</span><span class=special>></span> <span class=identifier>equal_range</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>CompatibleKey</span><span class=special>&</span> <span class=identifier>x</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span>
- <span class=keyword>typename</span> <span class=identifier>CompatibleKey</span><span class=special>,</span><span class=keyword>typename</span> <span class=identifier>CompatibleHash</span><span class=special>,</span> <span class=keyword>typename</span> <span class=identifier>CompatiblePred</span>
- <span class=special>></span>
- <span class=identifier>std</span><span class=special>::</span><span class=identifier>pair</span><span class=special><</span><span class=identifier>iterator</span><span class=special>,</span><span class=identifier>iterator</span><span class=special>></span> <span class=identifier>equal_range</span><span class=special>(</span>
- <span class=keyword>const</span> <span class=identifier>CompatibleKey</span><span class=special>&</span> <span class=identifier>x</span><span class=special>,
- </span><span class=keyword>const</span> <span class=identifier>CompatibleHash</span><span class=special>&</span> <span class=identifier>hash</span><span class=special>,</span><span class=keyword>const</span> <span class=identifier>CompatiblePred</span><span class=special>&</span> <span class=identifier>eq</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=comment>// bucket interface:</span>
- <span class=identifier>size_type</span> <span class=identifier>bucket_count</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=identifier>size_type</span> <span class=identifier>max_bucket_count</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=identifier>size_type</span> <span class=identifier>bucket_size</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>size_type</span> <span class=identifier>bucket</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>key_type</span><span class=special>&</span> <span class=identifier>k</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>local_iterator</span> <span class=identifier>begin</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>);</span>
- <span class=identifier>const_local_iterator</span> <span class=identifier>begin</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>local_iterator</span> <span class=identifier>end</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>);</span>
- <span class=identifier>const_local_iterator</span> <span class=identifier>end</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>const_local_iterator</span> <span class=identifier>cbegin</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>const_local_iterator</span> <span class=identifier>cend</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=identifier>local_iterator</span> <span class=identifier>local_iterator_to</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>value_type</span><span class=special>&</span> <span class=identifier>x</span><span class=special>);</span>
- <span class=identifier>const_local_iterator</span> <span class=identifier>local_iterator_to</span><span class=special>(</span><span class=keyword>const</span> <span class=identifier>value_type</span><span class=special>&</span> <span class=identifier>x</span><span class=special>)</span><span class=keyword>const</span><span class=special>;</span>
- <span class=comment>// hash policy:</span>
- <span class=keyword>float</span> <span class=identifier>load_factor</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=keyword>float</span> <span class=identifier>max_load_factor</span><span class=special>()</span><span class=keyword>const</span> <span class=keyword>noexcept</span><span class=special>;</span>
- <span class=keyword>void</span> <span class=identifier>max_load_factor</span><span class=special>(</span><span class=keyword>float</span> <span class=identifier>z</span><span class=special>);</span>
- <span class=keyword>void</span> <span class=identifier>rehash</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>);</span>
- <span class=keyword>void</span> <span class=identifier>reserve</span><span class=special>(</span><span class=identifier>size_type</span> <span class=identifier>n</span><span class=special>);</span>
- <span class=special>};</span>
- <span class=comment>// index comparison:</span>
- <span class=keyword>template</span><span class=special><</span><b>implementation defined</b><span class=special>></span>
- <span class=keyword>bool</span> <span class=keyword>operator</span><span class=special>==(</span><span class=keyword>const</span> <b>index class name</b><span class=special>&</span> <span class=identifier>x</span><span class=special>,</span><span class=keyword>const</span> <b>index class name</b><span class=special>&</span> <span class=identifier>y</span><span class=special>)</span><span class=special>;</span>
- <span class=keyword>template</span><span class=special><</span><b>implementation defined</b><span class=special>></span>
- <span class=keyword>bool</span> <span class=keyword>operator</span><span class=special>!=(</span><span class=keyword>const</span> <b>index class name</b><span class=special>&</span> <span class=identifier>x</span><span class=special>,</span><span class=keyword>const</span> <b>index class name</b><span class=special>&</span> <span class=identifier>y</span><span class=special>)</span>
- <span class=special>{</span>
- <span class=keyword>return</span> <span class=special>!(</span><span class=identifier>x</span><span class=special>==</span><span class=identifier>y</span><span class=special>);</span>
- <span class=special>}</span>
- <span class=comment>// index specialized algorithms:</span>
- <span class=keyword>template</span><span class=special><</span><b>implementation defined</b><span class=special>></span>
- <span class=keyword>void</span> <span class=identifier>swap</span><span class=special>(</span><b>index class name</b><span class=special>&</span> <span class=identifier>x</span><span class=special>,</span><b>index class name</b><span class=special>&</span> <span class=identifier>y</span><span class=special>);</span>
- <span class=special>}</span> <span class=comment>// namespace boost::multi_index::detail</span>
- <span class=special>}</span> <span class=comment>// namespace boost::multi_index</span>
- <span class=special>}</span> <span class=comment>// namespace boost</span>
- </pre></blockquote>
- <h4><a name="complexity_signature">Complexity signature</a></h4>
- <p>
- Here and in the descriptions of operations of hashed indices, we adopt the
- scheme outlined in the
- <a href="indices.html#complexity_signature">complexity signature
- section</a>. The complexity signature of hashed indices is:
- <ul>
- <li>copying: <code>c(n)=n*log(n)</code>,</li>
- <li>insertion: average case <code>i(n)=1</code> (amortized constant),
- worst case <code>i(n)=n<sub>dist</sub></code>,</li>
- <li>hinted insertion: average case <code>h(n)=1</code> (amortized constant),
- worst case <code>h(n)=n<sub>dist</sub></code>,</li>
- <li>deletion: <code>d(n)=1</code> (constant),</li>
- <li>replacement:
- <ul>
- <li>if the new element key is equivalent to the original, <code>r(n)=1</code> (constant),</li>
- <li>otherwise, average case <code>r(n)=1</code> (constant),
- worst case <code>r(n)=n<sub>dist</sub></code>,</li>
- </ul></li>
- <li>modifying: average case <code>m(n)=1</code> (constant),
- worst case <code>m(n)=n<sub>dist</sub></code>,</li>
- </ul>
- where <code>n<sub>dist</sub></code> is the number of non-equivalent elements out of
- the total <code>n</code>.
- </p>
- <h4><a name="instantiation_types">Instantiation types</a></h4>
- <p>Hashed indices are instantiated internally to <code>multi_index_container</code> and
- specified by means of <a href="indices.html#indexed_by"><code>indexed_by</code></a>
- with <a href="#unique_non_unique"> index specifiers <code>hashed_unique</code>
- and <code>hashed_non_unique</code></a>. Instantiations are dependent on the
- following types:
- <ul>
- <li><code>Value</code> from <code>multi_index_container</code>,</li>
- <li><code>Allocator</code> from <code>multi_index_container</code>,</li>
- <li><code>TagList</code> from the index specifier (if provided, otherwise <code>tag<></code> is assumed),</li>
- <li><code>KeyFromValue</code> from the index specifier,</li>
- <li><code>Hash</code> from the index specifier,</li>
- <li><code>Pred</code> from the index specifier.</li>
- </ul>
- <code>TagList</code> must be an instantiation of
- <a href="indices.html#tag"><code>tag</code></a>. The type <code>KeyFromValue</code>,
- which determines the mechanism for extracting a key from <code>Value</code>,
- must be a model of <a href="key_extraction.html#key_extractors">
- <code>Key Extractor</code></a> from <code>Value</code>. <code>Hash</code> is a
- <code>CopyConstructible</code>unary function object
- taking a single argument of type <code>KeyFromValue::result_type</code> and returning a
- value of type <code>std::size_t</code> in the range
- <code>[0, std::numeric_limits<std::size_t>::max())</code>.
- <code>Pred</code> is a <code>CopyConstructible</code> binary predicate inducing an equivalence relation
- on elements of <code>KeyFromValue::result_type</code>. It is required that
- the <code>Hash</code> object return the same value for keys
- equivalent under <code>Pred</code>.
- </p>
- <h4><a name="types">Nested types</a></h4>
- <code>ctor_args</code>
- <blockquote>
- The first element of this tuple indicates the minimum number of buckets
- set up by the index on construction time. If the default value 0 is used,
- an implementation defined number is used instead.
- </blockquote>
- <code>iterator<br>
- const_iterator<br>
- local_iterator<br>
- const_local_iterator</code>
- <blockquote>
- These types are forward iterators.
- </blockquote>
- <h4><a name="constructors">Constructors, copy and assignment</a></h4>
- <p>
- As explained in the <a href="indices.html#index_concepts">index
- concepts section</a>, indices do not have public constructors or destructors.
- Assignment, on the other hand, is provided. Upon construction,
- <code>max_load_factor()</code> is 1.0.
- </p>
- <code><b>index class name</b>& operator=(const <b>index class name</b>& x);</code>
- <blockquote>
- <b>Effects:</b>
- <blockquote><pre>
- <span class=identifier>a</span><span class=special>=</span><span class=identifier>b</span><span class=special>;</span>
- </pre></blockquote>
- where <code>a</code> and <code>b</code> are the <code>multi_index_container</code>
- objects to which <code>*this</code> and <code>x</code> belong, respectively.<br>
- <b>Returns:</b> <code>*this</code>.<br>
- </blockquote>
- <code><b>index class name</b>& operator=(std::initializer_list<value_type> list);</code>
- <blockquote>
- <b>Effects:</b>
- <blockquote><pre>
- <span class=identifier>a</span><span class=special>=</span><span class=identifier>list</span><span class=special>;</span>
- </pre></blockquote>
- where <code>a</code> is the <code>multi_index_container</code>
- object to which <code>*this</code> belongs.<br>
- <b>Returns:</b> <code>*this</code>.<br>
- </blockquote>
- <h4><a name="iterators">Iterators</a></h4>
- <code>iterator iterator_to(const value_type& x);<br>
- const_iterator iterator_to(const value_type& x)const;</code>
-
- <blockquote>
- <b>Requires:</b> <code>x</code> is a reference to an element of the container.<br>
- <b>Returns:</b> An iterator to <code>x</code>.<br>
- <b>Complexity:</b> Constant.<br>
- <b>Exception safety:</b> <code>nothrow</code>.<br>
- </blockquote>
- <h4><a name="modifiers">Modifiers</a></h4>
- <code>template<typename... Args><br>
- std::pair<iterator,bool> emplace(Args&&... args);</code>
- <blockquote>
- <b>Requires:</b> <code>value_type</code> is <code>EmplaceConstructible</code>
- into <code>multi_index_container</code> from <code>args</code>.<br>
- <b>Effects:</b> Inserts a <code>value_type</code> object constructed with
- <code>std::forward<Args>(args)...</code> into the <code>multi_index_container</code> to which
- the index belongs if
- <ul>
- <li>the index is non-unique OR no other element exists with
- equivalent key,</li>
- <li>AND insertion is allowed by all other indices of the
- <code>multi_index_container</code>.</li>
- </ul>
- <b>Returns:</b> The return value is a pair <code>p</code>. <code>p.second</code>
- is <code>true</code> if and only if insertion took place. On successful insertion,
- <code>p.first</code> points to the element inserted; otherwise, <code>p.first</code>
- points to an element that caused the insertion to be banned. Note that more than
- one element can be causing insertion not to be allowed.<br>
- <b>Complexity:</b> <code>O(I(n))</code>.<br>
- <b>Exception safety:</b> Strong, except that rehashing may occur even if the operation fails.<br>
- </blockquote>
- <code>template<typename... Args><br>
- iterator emplace_hint(iterator position, Args&&... args);</code>
- <blockquote>
- <b>Requires:</b> <code>value_type</code> is <code>EmplaceConstructible</code>
- into <code>multi_index_container</code> from <code>args</code>.
- <code>position</code> is a valid iterator of the index.<br>
- <b>Effects:</b> Inserts a <code>value_type</code> object constructed with
- <code>std::forward<Args>(args)...</code> into the <code>multi_index_container</code> to which
- the index belongs if
- <ul>
- <li>the index is non-unique OR no other element exists with
- equivalent key,</li>
- <li>AND insertion is allowed by all other indices of the
- <code>multi_index_container</code>.</li>
- </ul>
- <code>position</code> is used as a hint to improve the efficiency of the
- operation.<br>
- <b>Returns:</b> On successful insertion, an iterator to the newly inserted
- element. Otherwise, an iterator to an element that caused the insertion to be
- banned. Note that more than one element can be causing insertion not to be
- allowed.<br>
- <b>Complexity:</b> <code>O(H(n))</code>.<br>
- <b>Exception safety:</b> Strong, except that rehashing may occur even if the operation fails.<br>
- </blockquote>
- <code>std::pair<iterator,bool> insert(const value_type& x);</code><br>
- <code>std::pair<iterator,bool> insert(value_type&& x);</code>
- <blockquote>
- <b>Requires (first version):</b> <code>value_type</code> is <code>CopyInsertable</code>
- into <code>multi_index_container</code>.<br>
- <b>Requires (second version):</b> <code>value_type</code> is <code>MoveInsertable</code>
- into <code>multi_index_container</code>.<br>
- <b>Effects:</b> Inserts <code>x</code> into the <code>multi_index_container</code> to which
- the index belongs if
- <ul>
- <li>the index is non-unique OR no other element exists with
- equivalent key,</li>
- <li>AND insertion is allowed by all other indices of the
- <code>multi_index_container</code>.</li>
- </ul>
- <b>Returns:</b> The return value is a pair <code>p</code>. <code>p.second</code>
- is <code>true</code> if and only if insertion took place. On successful insertion,
- <code>p.first</code> points to the element inserted; otherwise, <code>p.first</code>
- points to an element that caused the insertion to be banned. Note that more than
- one element can be causing insertion not to be allowed.<br>
- <b>Complexity:</b> <code>O(I(n))</code>.<br>
- <b>Exception safety:</b> Strong, except that rehashing may occur even if the operation fails.<br>
- </blockquote>
- <code>iterator insert(iterator position,const value_type& x);</code><br>
- <code>iterator insert(iterator position,value_type&& x);</code>
- <blockquote>
- <b>Requires (first version):</b> <code>value_type</code> is <code>CopyInsertable</code>
- into <code>multi_index_container</code>.
- <code>position</code> is a valid iterator of the index.<br>
- <b>Requires (second version):</b> <code>value_type</code> is <code>MoveInsertable</code>
- into <code>multi_index_container</code>.
- <code>position</code> is a valid iterator of the index.<br>
- <b>Effects:</b> Inserts <code>x</code> into the <code>multi_index_container</code> to which
- the index belongs if
- <ul>
- <li>the index is non-unique OR no other element exists with
- equivalent key,</li>
- <li>AND insertion is allowed by all other indices of the
- <code>multi_index_container</code>.</li>
- </ul>
- <code>position</code> is used as a hint to improve the efficiency of the
- operation.<br>
- <b>Returns:</b> On successful insertion, an iterator to the newly inserted
- element. Otherwise, an iterator to an element that caused the insertion to be
- banned. Note that more than one element can be causing insertion not to be
- allowed.<br>
- <b>Complexity:</b> <code>O(H(n))</code>.<br>
- <b>Exception safety:</b> Strong, except that rehashing may occur even if the operation fails.<br>
- </blockquote>
- <code>template<typename InputIterator><br>
- void insert(InputIterator first,InputIterator last);</code>
- <blockquote>
- <b>Requires:</b> <code>InputIterator</code> is an input iterator.
- <code>value_type</code> is
- <code>EmplaceConstructible</code> into
- <code>multi_index_container</code> from <code>*first</code>.
- <code>first</code> and <code>last</code> are not iterators into any
- index of the <code>multi_index_container</code> to which this index belongs.
- <code>last</code> is reachable from <code>first</code>.<br>
- <b>Effects:</b>
- For each element of [<code>first</code>, <code>last</code>), in this
- order, inserts it into the <code>multi_index_container</code>
- to which this index belongs if
- <ul>
- <li>the index is non-unique OR no other element exists with
- equivalent key,</li>
- <li>AND insertion is allowed by all other indices of the
- <code>multi_index_container</code>.</li>
- </ul>
- <b>Complexity:</b> <code>O(m*I(n+m))</code>, where
- <code>m</code> is the number of elements in [<code>first</code>,
- <code>last</code>).<br>
- <b>Exception safety:</b> Basic.<br>
- </blockquote>
- <code>void insert(std::initializer_list<value_type> list);</code>
- <blockquote>
- <b>Effects:</b>
- <blockquote><pre>
- <span class=identifier>insert</span><span class=special>(</span><span class=identifier>list</span><span class=special>.</span><span class=identifier>begin</span><span class=special>(),</span><span class=identifier>list</span><span class=special>.</span><span class=identifier>end</span><span class=special>())</span><span class=special>;</span>
- </pre></blockquote>
- </blockquote>
-
- <code>iterator erase(iterator position);</code>
- <blockquote>
- <b>Requires:</b> <code>position</code> is a valid dereferenceable iterator
- of the index.<br>
- <b>Effects:</b> Deletes the element pointed to by <code>position</code>.<br>
- <b>Returns:</b> An iterator pointing to the element immediately following
- the one that was deleted, or <code>end()</code>
- if no such element exists.<br>
- <b>Complexity:</b> <code>O(D(n))</code>.<br>
- <b>Exception safety:</b> <code>nothrow</code>.<br>
- </blockquote>
- <code>size_type erase(const key_type& x);</code>
- <blockquote>
- <b>Effects:</b> Deletes the elements with key equivalent to <code>x</code>.<br>
- <b>Returns:</b> Number of elements deleted.<br>
- <b>Complexity:</b> Average case, <code>O(1 + m*D(n))</code>, worst case
- <code>O(n<sub>dist</sub> + m*D(n))</code>, where <code>m</code> is
- the number of elements deleted.<br>
- <b>Exception safety:</b> Basic.<br>
- </blockquote>
- <code>iterator erase(iterator first,iterator last);</code>
- <blockquote>
- <b>Requires:</b> [<code>first</code>,<code>last</code>) is a valid
- range of the index.<br>
- <b>Effects:</b> Deletes the elements in [<code>first</code>,<code>last</code>).<br>
- <b>Returns:</b> <code>last</code>.<br>
- <b>Complexity:</b> <code>O(m*D(n))</code>, where <code>m</code> is
- the number of elements in [<code>first</code>,<code>last</code>).<br>
- <b>Exception safety:</b> <code>nothrow</code>.<br>
- </blockquote>
- <a name="replace"><code>bool replace(iterator position,const value_type& x);</code></a><br>
- <code>bool replace(iterator position,value_type&& x);</code>
- <blockquote>
- <b>Requires (first version):</b> <code>value_type</code> is <code>CopyAssignable</code>.
- <code>position</code> is a valid dereferenceable iterator of the index.<br>
- <b>Requires (second version):</b> <code>value_type</code> is <code>MoveAssignable</code>.
- <code>position</code> is a valid dereferenceable iterator of the index.<br>
- <b>Effects:</b> Assigns the value <code>x</code> to the element pointed
- to by <code>position</code> into the <code>multi_index_container</code> to which
- the index belongs if, for the value <code>x</code>
- <ul>
- <li>the index is non-unique OR no other element exists
- (except possibly <code>*position</code>) with equivalent key,</li>
- <li>AND replacing is allowed by all other indices of the
- <code>multi_index_container</code>.</li>
- </ul>
- <b>Postconditions:</b> Validity of <code>position</code> is preserved
- in all cases. If the key of the new value is equivalent to that of the replaced value,
- the position of the element does not change.<br>
- <b>Returns:</b> <code>true</code> if the replacement took place,
- <code>false</code> otherwise.<br>
- <b>Complexity:</b> <code>O(R(n))</code>.<br>
- <b>Exception safety:</b> Strong. If an exception is thrown by some
- user-provided operation the <code>multi_index_container</code> to which the index
- belongs remains in its original state.
- </blockquote>
-
- <a name="modify">
- <code>template<typename Modifier> bool modify(iterator position,Modifier mod);</code></a>
- <blockquote>
- <b>Requires:</b> <code>mod</code> is a unary function object
- accepting arguments of type
- <code>value_type&</code>. <code>position</code> is a valid dereferenceable
- iterator of the index.
- The execution of <code>mod(e)</code>, where <code>e</code> is the element
- pointed to by <code>position</code>, does not invoke any operation of the
- <code>multi_index_container</code> after <code>e</code> is directly modified
- or, before modification, if the operation would invalidate <code>position</code>.<br>
- <b>Effects:</b> Calls <code>mod(e)</code> where <code>e</code> is the element
- pointed to by <code>position</code> and rearranges <code>*position</code> into
- all the indices of the <code>multi_index_container</code>. Rearrangement is successful if
- <ul>
- <li>the index is non-unique OR no other element exists
- with equivalent key,</li>
- <li>AND rearrangement is allowed by all other indices of the
- <code>multi_index_container</code>.</li>
- </ul>
- If the rearrangement fails, the element is erased.<br>
- <b>Postconditions:</b> Validity of <code>position</code> is preserved if the
- operation succeeds. If the key of the modified value is equivalent to that of the
- original value, the position of the element does not change.<br>
- <b>Returns:</b> <code>true</code> if the operation succeeded, <code>false</code>
- otherwise.<br>
- <b>Complexity:</b> <code>O(M(n))</code>.<br>
- <b>Exception safety:</b> Basic. If an exception is thrown by some
- user-provided operation (including <code>mod</code>), then
- the element pointed to by <code>position</code> is erased.
- </blockquote>
- <code>template<typename Modifier,typename Rollback><br>
- bool modify(iterator position,Modifier mod,Rollback back);</code>
- <blockquote>
- <b>Requires:</b> <code>mod</code> and <code>back</code> are unary function
- objects accepting arguments of type
- <code>value_type&</code>. <code>position</code> is a valid dereferenceable
- iterator of the index.
- The execution of <code>mod(e)</code>, where <code>e</code> is the element
- pointed to by <code>position</code>, does not invoke any operation of the
- <code>multi_index_container</code> after <code>e</code> is directly modified
- or, before modification, if the operation would invalidate <code>position</code>.
- <code>back(e)</code> does not invoke any operation of the
- <code>multi_index_container</code>.<br>
- <b>Effects:</b> Calls <code>mod(e)</code> where <code>e</code> is the element
- pointed to by <code>position</code> and tries to rearrange <code>*position</code> into
- all the indices of the <code>multi_index_container</code>. Rearrangement is successful if
- <ul>
- <li>the index is non-unique OR no other element exists
- with equivalent key,</li>
- <li>AND rearrangement is allowed by all other indices of the
- <code>multi_index_container</code>.</li>
- </ul>
- If the rearrangement fails, <code>back(e)</code> is invoked: if the resulting value
- of <code>e</code> is consistent with its original position and constraints in all
- indices, the element is kept, otherwise it is erased.<br>
- <b>Postconditions:</b> Validity of <code>position</code> is preserved except if
- the element is erased under the conditions described below.
- If the key of the modified value is equivalent to that of the
- original value, the position of the element does not change.<br>
- <b>Returns:</b> <code>true</code> if the operation succeeded, <code>false</code>
- otherwise.<br>
- <b>Complexity:</b> <code>O(M(n))</code>.<br>
- <b>Exception safety:</b> Strong, except if <code>mod</code> or <code>back</code> throw an
- exception or <code>back(e)</code> fails to properly restore the element or there is
- a throwing user-provided operation after invoking <code>back(e)</code>, in which cases
- the modified element is erased. If <code>back</code>
- throws inside the handling code executing after some other user-provided
- operation has thrown, it is the exception generated by <code>back</code> that
- is rethrown.
- </blockquote>
- <a name="modify_key">
- <code>template<typename Modifier> bool modify_key(iterator position,Modifier mod);</code></a>
- <blockquote>
- <b>Requires:</b> <code>key_from_value</code> is a read/write
- <a href="key_extraction.html#key_extractors"><code>Key Extractor</code></a>
- from <code>value_type</code>. <code>mod</code> is a
- unary function object accepting arguments of type
- <code>key_type&</code>. <code>position</code> is a valid dereferenceable
- iterator of the index.
- The execution of <code>mod(k)</code>, where <code>k</code> is the key of the element
- pointed to by <code>position</code>, does not invoke any operation of the
- <code>multi_index_container</code> after <code>k</code> is directly modified
- or, before modification, if the operation would invalidate <code>position</code>.<br>
- <b>Effects:</b> Equivalent to <code>modify(position,mod')</code>,
- with <code>mod'</code> defined in such a way that
- <code>mod'(x)</code> is the same as <code>mod(key(x))</code>, where
- <code>key</code> is the internal <code>KeyFromValue</code> object of the index.
- </blockquote>
- <code>template<typename Modifier,typename Rollback><br>
- bool modify_key(iterator position,Modifier mod,Rollback back);</code>
- <blockquote>
- <b>Requires:</b> <code>key_from_value</code> is a read/write
- <a href="key_extraction.html#key_extractors"><code>Key Extractor</code></a>
- from <code>value_type</code>. <code>mod</code> and <code>back</code>
- are unary function objects accepting arguments of type
- <code>key_type&</code>. <code>position</code> is a valid dereferenceable
- iterator of the index.
- The execution of <code>mod(k)</code>, where <code>k</code> is the key of the element
- pointed to by <code>position</code>, does not invoke any operation of the
- <code>multi_index_container</code> after <code>k</code> is directly modified
- or, before modification, if the operation would invalidate <code>position</code>.
- <code>back(k)</code> does not invoke any operation of the
- <code>multi_index_container</code>.<br>
- <b>Effects:</b> Equivalent to <code>modify(position,mod',back')</code>,
- with <code>mod'</code> and <code>back</code> defined in such a way that
- <code>mod'(x)</code> is the same as <code>mod(key(x))</code> and
- <code>back'(x)</code> is the same as <code>back(key(x))</code>, where
- <code>key</code> is the internal <code>KeyFromValue</code> object of the index.
- </blockquote>
- <h4><a name="observers">Observers</a></h4>
- <p>Apart from standard <code>hash_function</code> and <code>key_eq</code>,
- hashed indices have a member function for retrieving the internal key extractor
- used.
- </p>
- <code>key_from_value key_extractor()const;</code>
- <blockquote>
- Returns a copy of the <code>key_from_value</code> object used to construct
- the index.<br>
- <b>Complexity:</b> Constant.
- </blockquote>
- <h4><a name="lookup">Lookup</a></h4>
- <p>
- Hashed indices provide the full lookup functionality required by
- <b>[unord.req]</b>, namely <code>find</code>,
- <code>count</code>, and <code>equal_range</code>. Additionally,
- these member functions are templatized to allow for non-standard
- arguments, so extending the types of search operations allowed.
- The kind of arguments permissible when invoking the lookup member
- functions is defined by the following concept.
- </p>
- <p>
- Consider a pair (<code>Hash</code>, <code>Pred</code>) where
- <code>Hash</code> is a hash functor over values of type <code>Key</code>
- and <code>Pred</code> is a binary predicate
- inducing an equivalence relation
- on <code>Key</code>, with the additional constraint that equivalent
- keys have the same hash value.
- A triplet of types (<code>CompatibleKey</code>, <code>CompatibleHash</code>,
- <code>CompatiblePred</code>) is said to be a <i>compatible extension</i>
- of (<code>Hash</code>, <code>Pred</code>) if
- <ol>
- <li><code>CompatibleHash</code> is a hash functor on values of
- type <code>CompatibleKey</code>,</li>
- <li><code>CompatiblePred</code> is a binary predicate over (<code>Key</code>,
- <code>CompatibleKey</code>),</li>
- <li><code>CompatiblePred</code> is a binary predicate over (<code>CompatibleKey</code>,
- <code>Key</code>),</li>
- <li>if <code>c_eq(ck,k1)</code> then <code>c_eq(k1,ck)</code>,</li>
- <li>if <code>c_eq(ck,k1)</code> and <code>eq(k1,k2)</code> then
- <code>c_eq(ck,k2)</code>,</li>
- <li>if <code>c_eq(ck,k1)</code> and <code>c_eq(ck,k2)</code> then
- <code>eq(k1,k2)</code>,</li>
- <li>if <code>c_eq(ck,k1)</code> then <code>c_hash(ck)==hash(k1)</code>,</li>
- </ol>
- for every <code>c_hash</code> of type <code>CompatibleHash</code>,
- <code>c_eq</code> of type <code>CompatiblePred</code>,
- <code>hash</code> of type <code>Hash</code>,
- <code>eq</code> of type <code>Pred</code>, <code>ck</code> of type
- <code>CompatibleKey</code> and <code>k1</code>, <code>k2</code> of type
- <code>Key</code>.
- </p>
- <p>Additionally, a type <code>CompatibleKey</code> is said to be a
- <i>compatible key</i> of (<code>Hash</code>, <code>Pred</code>) if
- (<code>CompatibleKey</code>, <code>Hash</code>, <code>Pred</code>)
- is a compatible extension of (<code>Hash</code>, <code>Pred</code>).
- This implies that <code>Hash</code> and <code>Pred</code> accept arguments
- of type <code>CompatibleKey</code>, which usually means they have
- several overloads of their corresponding <code>operator()</code>
- member functions.
- </p>
- <p>
- In the context of a compatible extension or a compatible key, the expression
- "equivalent key" takes on its obvious interpretation.
- </p>
- <code>template<typename CompatibleKey> iterator find(const CompatibleKey& x)const;
- </code>
- <blockquote>
- <b>Requires:</b> <code>CompatibleKey</code> is a compatible key of
- (<code>hasher</code>, <code>key_equal</code>).<br>
- <b>Effects:</b> Returns a pointer to an element whose key is equivalent to
- <code>x</code>, or <code>end()</code> if such an element does not exist.<br>
- <b>Complexity:</b> Average case <code>O(1)</code> (constant), worst case
- <code>O(n<sub>dist</sub>)</code>.<br>
- </blockquote>
- <code>template<<br>
- typename CompatibleKey,typename CompatibleHash, typename CompatiblePred<br>
- ><br>
- iterator find(<br>
- const CompatibleKey& x,<br>
- const CompatibleHash& hash,const CompatiblePred& eq)const;
- </code>
- <blockquote>
- <b>Requires:</b> (<code>CompatibleKey</code>, <code>CompatibleHash</code>,
- <code>CompatiblePred</code>) is a compatible extension of
- (<code>hasher</code>, <code>key_equal</code>).<br>
- <b>Effects:</b> Returns a pointer to an element whose key is equivalent to
- <code>x</code>, or <code>end()</code> if such an element does not exist.<br>
- <b>Complexity:</b> Average case <code>O(1)</code> (constant), worst case
- <code>O(n<sub>dist</sub>)</code>.<br>
- </blockquote>
- <code>template<typename CompatibleKey><br>
- size_type count(const CompatibleKey& x)const;
- </code>
- <blockquote>
- <b>Requires:</b> <code>CompatibleKey</code> is a compatible key of
- (<code>hasher</code>, <code>key_equal</code>).<br>
- <b>Effects:</b> Returns the number of elements with key equivalent to <code>x</code>.<br>
- <b>Complexity:</b> Average case <code>O(count(x))</code>, worst case
- <code>O(count(x)+n<sub>dist</sub>)</code>.<br>
- </blockquote>
- <code>template<<br>
- typename CompatibleKey,typename CompatibleHash, typename CompatiblePred<br>
- ><br>
- size_type count(<br>
- const CompatibleKey& x,<br>
- const CompatibleHash& hash,const CompatiblePred& eq)const;
- </code>
- <blockquote>
- <b>Requires:</b> (<code>CompatibleKey</code>, <code>CompatibleHash</code>,
- <code>CompatiblePred</code>) is a compatible extension of
- (<code>hasher</code>, <code>key_equal</code>).<br>
- <b>Effects:</b> Returns the number of elements with key equivalent to <code>x</code>.<br>
- <b>Complexity:</b> Average case <code>O(count(x,hash,eq))</code>, worst case
- <code>O(count(x,hash,eq)+n<sub>dist</sub>)</code>.<br>
- </blockquote>
- <code>template<typename CompatibleKey><br>
- std::pair<iterator,iterator> equal_range(const CompatibleKey& x)const;
- </code>
- <blockquote>
- <b>Requires:</b> <code>CompatibleKey</code> is a compatible key of
- (<code>hasher</code>, <code>key_equal</code>).<br>
- <b>Effects:</b> Returns a range containing all elements with keys equivalent
- to <code>x</code> (and only those), or (<code>end()</code>,<code>end()</code>)
- if no such elements exist.<br>
- <b>Complexity:</b> Average case <code>O(1)</code> (constant), worst case
- <code>O(n<sub>dist</sub>)</code>.<br>
- </blockquote>
- <code>template<<br>
- typename CompatibleKey,typename CompatibleHash, typename CompatiblePred<br>
- ><br>
- std::pair<iterator,iterator> equal_range(<br>
- const CompatibleKey& x,<br>
- const CompatibleHash& hash,const CompatiblePred& eq)const;
- </code>
- <blockquote>
- <b>Requires:</b> (<code>CompatibleKey</code>, <code>CompatibleHash</code>,
- <code>CompatiblePred</code>) is a compatible extension of
- (<code>hasher</code>, <code>key_equal</code>).<br>
- <b>Effects:</b> Returns a range containing all elements with keys equivalent
- to <code>x</code> (and only those), or (<code>end()</code>,<code>end()</code>)
- if no such elements exist.<br>
- <b>Complexity:</b> Average case <code>O(1)</code> (constant), worst case
- <code>O(n<sub>dist</sub>)</code>.<br>
- </blockquote>
- <h4><a name="bucket_interface">Bucket interface</a></h4>
- <code>local_iterator local_iterator_to(const value_type& x);<br>
- const_local_iterator local_iterator_to(const value_type& x)const;</code>
-
- <blockquote>
- <b>Requires:</b> <code>x</code> is a reference to an element of the container.<br>
- <b>Returns:</b> An iterator to <code>x</code>.<br>
- <b>Complexity:</b> Constant.<br>
- <b>Exception safety:</b> <code>nothrow</code>.<br>
- </blockquote>
- <h4><a name="hash_policy">Hash policy</a></h4>
- <code>void rehash(size_type n);</code>
- <blockquote>
- <b>Effects:</b> Increases if necessary the number of internal buckets
- so that <code>size()/bucket_count()</code> does not exceed the maximum
- load factor, and <code>bucket_count()>=n</code>.<br>
- <b>Postconditions:</b> Validity of iterators and references to the
- elements contained is preserved.<br>
- <b>Complexity:</b> <code>O(m)</code>, where <code>m</code> is the number of
- non-equivalent elements in the index.<br>
- <b>Exception safety:</b> Strong.
- </blockquote>
- <code>void reserve(size_type n);</code>
- <blockquote>
- <b>Effects:</b>
- <blockquote><pre>
- <span class=identifier>rehash</span><span class=special>(</span><span class=identifier>std</span><span class=special>::</span><span class=identifier>ceil</span><span class=special>(</span><span class=identifier>n</span><span class=special>/</span><span class=identifier>max_load_factor</span><span class=special>()));</span>
- </pre></blockquote>
- </blockquote>
- <h4><a name="comparison">Comparison</a></h4>
- <code>template<<i>implementation defined</i>><br>
- bool operator==(const <i>index class name</i>& x,const <i>index class name</i>& y);</code>
- <blockquote>
- <b>Requires:</b> <code>x.key_extractor()</code>, <code>x.hash_function()</code> and
- <code>x.key_eq()</code> have the same behavior as the corresponding objects in <code>y</code>.
- For any two elements <code>e1</code>, <code>e2</code> in <code>x</code> or <code>y</code>,
- if <code>e1==e2</code> then their keys are equivalent.<br>
- <b>Returns:</b> <code>true</code> iff <code>x</code> and <code>y</code> have the same size
- and for each key <code>k</code> present in <code>x</code> the range
- <code>x.equal_range(k)</code> is equal (considering the <code>==</code> operator of <code>value_type</code>)
- to <code>y.equal_range(k)</code> under permutations of the elements.<br>
- <b>Complexity:</b> Let <code>k<sub>1</sub></code>,...,<code>k<sub>m</sub></code> be the different
- keys present in <code>x</code>:<br>
- <ul>
- <li>If, for each <code>k<sub>i</sub></code>, <code>x.equal_range(k<sub>i</sub>)</code> is arranged
- in the same order as <code>y.equal_range(k<sub>i</sub>)</code>, average case is
- <code>O(x.size())</code>, worst case <code>O(x.size()<sup>2</sup>)</code>.
- </li>
- <li>Otherwise, average case is
- <code>O(<font style="font-size:1.5em">Σ</font>(x.count(k<sub>i</sub>)<sup>2</sup>))</code>,
- worst case <code>O(x.size()<sup>2</sup>)</code>.
- </li>
- </ul>
- (For unique indices, the formulas above reduce to average case
- <code>O(x.size())</code>, worst case <code>O(x.size()<sup>2</sup>)</code>.)
- </blockquote>
- <h4><a name="serialization">Serialization</a></h4>
- <p>
- Indices cannot be serialized on their own, but only as part of the
- <code>multi_index_container</code> into which they are embedded. In describing
- the additional preconditions and guarantees associated to hashed indices
- with respect to serialization of their embedding containers, we
- use the concepts defined in the <code>multi_index_container</code>
- <a href="multi_index_container.html#serialization">serialization section</a>.
- </p>
- Operation: saving of a <code>multi_index_container</code> <code>m</code> to an
- output archive (XML archive) <code>ar</code>.
- <blockquote>
- <b>Requires:</b> No additional requirements to those imposed by the container.
- </blockquote>
- Operation: loading of a <code>multi_index_container</code> <code>m'</code> from an
- input archive (XML archive) <code>ar</code>.
- <blockquote>
- <b>Requires:</b> Additionally to the general requirements, <code>key_eq()</code>
- must be serialization-compatible with <code>m.get<i>().key_eq()</code>,
- where <code>i</code> is the position of the hashed index in the container.<br>
- <b>Postconditions:</b> On successful loading, the range
- [<code>begin()</code>, <code>end()</code>) contains restored copies of every
- element in [<code>m.get<i>().begin()</code>, <code>m.get<i>().end()</code>),
- though not necessarily in the same order.
- </blockquote>
- Operation: saving of an <code>iterator</code> or <code>const_iterator</code>
- <code>it</code> to an output archive (XML archive) <code>ar</code>.
- <blockquote>
- <b>Requires:</b> <code>it</code> is a valid iterator of the index. The associated
- <code>multi_index_container</code> has been previously saved.
- </blockquote>
- Operation: loading of an <code>iterator</code> or <code>const_iterator</code>
- <code>it'</code> from an input archive (XML archive) <code>ar</code>.
- <blockquote>
- <b>Postconditions:</b> On successful loading, if <code>it</code> was dereferenceable
- then <code>*it'</code> is the restored copy of <code>*it</code>, otherwise
- <code>it'==end()</code>.<br>
- <b>Note:</b> It is allowed that <code>it</code> be a <code>const_iterator</code>
- and the restored <code>it'</code> an <code>iterator</code>, or vice versa.
- </blockquote>
- Operation: saving of a <code>local_iterator</code> or
- <code>const_local_iterator</code>
- <code>it</code> to an output archive (XML archive) <code>ar</code>.
- <blockquote>
- <b>Requires:</b> <code>it</code> is a valid local iterator of the index. The
- associated <code>multi_index_container</code> has been previously saved.
- </blockquote>
- Operation: loading of a <code>local_iterator</code> or
- <code>const_local_iterator</code>
- <code>it'</code> from an input archive (XML archive) <code>ar</code>.
- <blockquote>
- <b>Postconditions:</b> On successful loading, if <code>it</code> was dereferenceable
- then <code>*it'</code> is the restored copy of <code>*it</code>; if <code>it</code>
- was <code>m.get<i>().end(n)</code> for some <code>n</code>, then
- <code>it'==m'.get<i>().end(n)</code> (where <code>m</code> is the original
- <code>multi_index_container</code>, <code>m'</code> its restored copy
- and <code>i</code> is the ordinal of the index.)<br>
- <b>Note:</b> It is allowed that <code>it</code> be a <code>const_local_iterator</code>
- and the restored <code>it'</code> a <code>local_iterator</code>, or vice versa.
- </blockquote>
- <hr>
- <div class="prev_link"><a href="rnk_indices.html"><img src="../prev.gif" alt="ranked indices" border="0"><br>
- Ranked indices
- </a></div>
- <div class="up_link"><a href="index.html"><img src="../up.gif" alt="Boost.MultiIndex reference" border="0"><br>
- Boost.MultiIndex reference
- </a></div>
- <div class="next_link"><a href="seq_indices.html"><img src="../next.gif" alt="sequenced indices" border="0"><br>
- Sequenced indices
- </a></div><br clear="all" style="clear: all;">
- <br>
- <p>Revised August 25th 2017</p>
- <p>© Copyright 2003-2017 Joaquín M López Muñoz.
- Distributed under the Boost Software
- License, Version 1.0. (See accompanying file <a href="../../../../LICENSE_1_0.txt">
- LICENSE_1_0.txt</a> or copy at <a href="http://www.boost.org/LICENSE_1_0.txt">
- http://www.boost.org/LICENSE_1_0.txt</a>)
- </p>
- </body>
- </html>
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