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| <div class="titlepage"><div><div><h4 class="title"> |
| <a name="boost_regex.ref.deprecated_interfaces.regex_split"></a><a class="link" href="regex_split.html" title="regex_split (deprecated)"> |
| regex_split (deprecated)</a> |
| </h4></div></div></div> |
| <p> |
| The algorithm <a class="link" href="regex_split.html" title="regex_split (deprecated)"><code class="computeroutput"><span class="identifier">regex_split</span></code></a> has been deprecated |
| in favor of the iterator <a class="link" href="../regex_token_iterator.html" title="regex_token_iterator"><code class="computeroutput"><span class="identifier">regex_token_iterator</span></code></a> which has |
| a more flexible and powerful interface, as well as following the more usual |
| standard library "pull" rather than "push" semantics. |
| </p> |
| <p> |
| Code which uses <a class="link" href="regex_split.html" title="regex_split (deprecated)"><code class="computeroutput"><span class="identifier">regex_split</span></code></a> will continue to compile, |
| the following documentation is taken from a previous Boost.Regex version: |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">regex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| </pre> |
| <p> |
| Algorithm <a class="link" href="regex_split.html" title="regex_split (deprecated)"><code class="computeroutput"><span class="identifier">regex_split</span></code></a> performs a similar |
| operation to the perl split operation, and comes in three overloaded forms: |
| </p> |
| <pre class="programlisting"><span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">OutputIterator</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">charT</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Traits1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Alloc1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Traits2</span><span class="special">></span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">regex_split</span><span class="special">(</span><span class="identifier">OutputIterator</span> <span class="identifier">out</span><span class="special">,</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span><span class="special"><</span><span class="identifier">charT</span><span class="special">,</span> <span class="identifier">Traits1</span><span class="special">,</span> <span class="identifier">Alloc1</span><span class="special">>&</span> <span class="identifier">s</span><span class="special">,</span> |
| <span class="keyword">const</span> <span class="identifier">basic_regex</span><span class="special"><</span><span class="identifier">charT</span><span class="special">,</span> <span class="identifier">Traits2</span><span class="special">>&</span> <span class="identifier">e</span><span class="special">,</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">match_flag_type</span> <span class="identifier">flags</span><span class="special">,</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">max_split</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">OutputIterator</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">charT</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Traits1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Alloc1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Traits2</span><span class="special">></span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">regex_split</span><span class="special">(</span><span class="identifier">OutputIterator</span> <span class="identifier">out</span><span class="special">,</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span><span class="special"><</span><span class="identifier">charT</span><span class="special">,</span> <span class="identifier">Traits1</span><span class="special">,</span> <span class="identifier">Alloc1</span><span class="special">>&</span> <span class="identifier">s</span><span class="special">,</span> |
| <span class="keyword">const</span> <span class="identifier">basic_regex</span><span class="special"><</span><span class="identifier">charT</span><span class="special">,</span> <span class="identifier">Traits2</span><span class="special">>&</span> <span class="identifier">e</span><span class="special">,</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">match_flag_type</span> <span class="identifier">flags</span> <span class="special">=</span> <span class="identifier">match_default</span><span class="special">);</span> |
| |
| <span class="keyword">template</span> <span class="special"><</span><span class="keyword">class</span> <span class="identifier">OutputIterator</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">charT</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Traits1</span><span class="special">,</span> <span class="keyword">class</span> <span class="identifier">Alloc1</span><span class="special">></span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">size_t</span> <span class="identifier">regex_split</span><span class="special">(</span><span class="identifier">OutputIterator</span> <span class="identifier">out</span><span class="special">,</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">basic_string</span><span class="special"><</span><span class="identifier">charT</span><span class="special">,</span> <span class="identifier">Traits1</span><span class="special">,</span> <span class="identifier">Alloc1</span><span class="special">>&</span> <span class="identifier">s</span><span class="special">);</span> |
| </pre> |
| <p> |
| <span class="bold"><strong>Effects</strong></span>: Each version of the algorithm |
| takes an output-iterator for output, and a string for input. If the expression |
| contains no marked sub-expressions, then the algorithm writes one string |
| onto the output-iterator for each section of input that does not match |
| the expression. If the expression does contain marked sub-expressions, |
| then each time a match is found, one string for each marked sub-expression |
| will be written to the output-iterator. No more than max_split strings |
| will be written to the output-iterator. Before returning, all the input |
| processed will be deleted from the string <span class="emphasis"><em>s</em></span> (if <span class="emphasis"><em>max_split</em></span> |
| is not reached then all of <span class="emphasis"><em>s</em></span> will be deleted). Returns |
| the number of strings written to the output-iterator. If the parameter |
| <span class="emphasis"><em>max_split</em></span> is not specified then it defaults to <code class="computeroutput"><span class="identifier">UINT_MAX</span></code>. If no expression is specified, |
| then it defaults to "\s+", and splitting occurs on whitespace. |
| </p> |
| <p> |
| <span class="bold"><strong>Throws</strong></span>: <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">runtime_error</span></code> |
| if the complexity of matching the expression against an N character string |
| begins to exceed O(N<sup>2</sup>), or if the program runs out of stack space while |
| matching the expression (if Boost.Regex is configured in recursive mode), |
| or if the matcher exhausts its permitted memory allocation (if Boost.Regex |
| is configured in non-recursive mode). |
| </p> |
| <p> |
| <span class="bold"><strong>Example</strong></span>: the following function will split |
| the input string into a series of tokens, and remove each token from the |
| string <span class="emphasis"><em>s</em></span>: |
| </p> |
| <pre class="programlisting"><span class="keyword">unsigned</span> <span class="identifier">tokenise</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">list</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">>&</span> <span class="identifier">l</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&</span> <span class="identifier">s</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="keyword">return</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex_split</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">l</span><span class="special">),</span> <span class="identifier">s</span><span class="special">);</span> |
| <span class="special">}</span> |
| </pre> |
| <p> |
| Example: the following short program will extract all of the URL's from |
| a html file, and print them out to cout: |
| </p> |
| <pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">list</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">fstream</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> |
| <span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">boost</span><span class="special">/</span><span class="identifier">regex</span><span class="special">.</span><span class="identifier">hpp</span><span class="special">></span> |
| |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex</span> <span class="identifier">e</span><span class="special">(</span><span class="string">"<\\s*A\\s+[^>]*href\\s*=\\s*\"([^\"]*)\""</span><span class="special">,</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regbase</span><span class="special">::</span><span class="identifier">normal</span> <span class="special">|</span> <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regbase</span><span class="special">::</span><span class="identifier">icase</span><span class="special">);</span> |
| |
| <span class="keyword">void</span> <span class="identifier">load_file</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">&</span> <span class="identifier">s</span><span class="special">,</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">istream</span><span class="special">&</span> <span class="identifier">is</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="identifier">s</span><span class="special">.</span><span class="identifier">erase</span><span class="special">();</span> |
| <span class="comment">// |
| </span> <span class="comment">// attempt to grow string buffer to match file size, |
| </span> <span class="comment">// this doesn't always work... |
| </span> <span class="identifier">s</span><span class="special">.</span><span class="identifier">reserve</span><span class="special">(</span><span class="identifier">is</span><span class="special">.</span><span class="identifier">rdbuf</span><span class="special">()-&</span><span class="identifier">gtin_avail</span><span class="special">());</span> |
| <span class="keyword">char</span> <span class="identifier">c</span><span class="special">;</span> |
| <span class="keyword">while</span><span class="special">(</span><span class="identifier">is</span><span class="special">.</span><span class="identifier">get</span><span class="special">(</span><span class="identifier">c</span><span class="special">))</span> |
| <span class="special">{</span> |
| <span class="comment">// use logarithmic growth stategy, in case |
| </span> <span class="comment">// in_avail (above) returned zero: |
| </span> <span class="keyword">if</span><span class="special">(</span><span class="identifier">s</span><span class="special">.</span><span class="identifier">capacity</span><span class="special">()</span> <span class="special">==</span> <span class="identifier">s</span><span class="special">.</span><span class="identifier">size</span><span class="special">())</span> |
| <span class="identifier">s</span><span class="special">.</span><span class="identifier">reserve</span><span class="special">(</span><span class="identifier">s</span><span class="special">.</span><span class="identifier">capacity</span><span class="special">()</span> <span class="special">*</span> <span class="number">3</span><span class="special">);</span> |
| <span class="identifier">s</span><span class="special">.</span><span class="identifier">append</span><span class="special">(</span><span class="number">1</span><span class="special">,</span> <span class="identifier">c</span><span class="special">);</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| |
| |
| <span class="keyword">int</span> <span class="identifier">main</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">argc</span><span class="special">,</span> <span class="keyword">char</span><span class="special">**</span> <span class="identifier">argv</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">s</span><span class="special">;</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">list</span><span class="special"><</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span><span class="special">></span> <span class="identifier">l</span><span class="special">;</span> |
| |
| <span class="keyword">for</span><span class="special">(</span><span class="keyword">int</span> <span class="identifier">i</span> <span class="special">=</span> <span class="number">1</span><span class="special">;</span> <span class="identifier">i</span> <span class="special"><</span> <span class="identifier">argc</span><span class="special">;</span> <span class="special">++</span><span class="identifier">i</span><span class="special">)</span> |
| <span class="special">{</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="string">"Findings URL's in "</span> <span class="special"><<</span> <span class="identifier">argv</span><span class="special">[</span><span class="identifier">i</span><span class="special">]</span> <span class="special"><<</span> <span class="string">":"</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> |
| <span class="identifier">s</span><span class="special">.</span><span class="identifier">erase</span><span class="special">();</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">ifstream</span> <span class="identifier">is</span><span class="special">(</span><span class="identifier">argv</span><span class="special">[</span><span class="identifier">i</span><span class="special">]);</span> |
| <span class="identifier">load_file</span><span class="special">(</span><span class="identifier">s</span><span class="special">,</span> <span class="identifier">is</span><span class="special">);</span> |
| <span class="identifier">boost</span><span class="special">::</span><span class="identifier">regex_split</span><span class="special">(</span><span class="identifier">std</span><span class="special">::</span><span class="identifier">back_inserter</span><span class="special">(</span><span class="identifier">l</span><span class="special">),</span> <span class="identifier">s</span><span class="special">,</span> <span class="identifier">e</span><span class="special">);</span> |
| <span class="keyword">while</span><span class="special">(</span><span class="identifier">l</span><span class="special">.</span><span class="identifier">size</span><span class="special">())</span> |
| <span class="special">{</span> |
| <span class="identifier">s</span> <span class="special">=</span> <span class="special">*(</span><span class="identifier">l</span><span class="special">.</span><span class="identifier">begin</span><span class="special">());</span> |
| <span class="identifier">l</span><span class="special">.</span><span class="identifier">pop_front</span><span class="special">();</span> |
| <span class="identifier">std</span><span class="special">::</span><span class="identifier">cout</span> <span class="special"><<</span> <span class="identifier">s</span> <span class="special"><<</span> <span class="identifier">std</span><span class="special">::</span><span class="identifier">endl</span><span class="special">;</span> |
| <span class="special">}</span> |
| <span class="special">}</span> |
| <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> |
| <span class="special">}</span> |
| </pre> |
| </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 © 1998 -2010 John Maddock<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> |
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