1<html> 2<head> 3<meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> 4<title>regex_split (deprecated)</title> 5<link rel="stylesheet" href="../../../../../../../doc/src/boostbook.css" type="text/css"> 6<meta name="generator" content="DocBook XSL Stylesheets V1.79.1"> 7<link rel="home" href="../../../index.html" title="Boost.Regex 5.1.4"> 8<link rel="up" href="../deprecated.html" title="Deprecated Interfaces"> 9<link rel="prev" href="regex_grep.html" title="regex_grep (Deprecated)"> 10<link rel="next" href="old_regex.html" title="High Level Class RegEx (Deprecated)"> 11</head> 12<body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"> 13<table cellpadding="2" width="100%"><tr> 14<td valign="top"><img alt="Boost C++ Libraries" width="277" height="86" src="../../../../../../../boost.png"></td> 15<td align="center"><a href="../../../../../../../index.html">Home</a></td> 16<td align="center"><a 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title="regex_split (deprecated)">regex_split 28 (deprecated)</a> 29</h4></div></div></div> 30<p> 31 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 32 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 33 a more flexible and powerful interface, as well as following the more usual 34 standard library "pull" rather than "push" semantics. 35 </p> 36<p> 37 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, 38 the following documentation is taken from a previous Boost.Regex version: 39 </p> 40<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> 41</pre> 42<p> 43 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 44 operation to the perl split operation, and comes in three overloaded forms: 45 </p> 46<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> 47<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> 48 <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> 49 <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> 50 <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> 51 <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> 52 53<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> 54<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> 55 <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> 56 <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> 57 <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> 58 59<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> 60<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> 61 <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> 62</pre> 63<p> 64 <span class="bold"><strong>Effects</strong></span>: Each version of the algorithm 65 takes an output-iterator for output, and a string for input. If the expression 66 contains no marked sub-expressions, then the algorithm writes one string 67 onto the output-iterator for each section of input that does not match 68 the expression. If the expression does contain marked sub-expressions, 69 then each time a match is found, one string for each marked sub-expression 70 will be written to the output-iterator. No more than max_split strings 71 will be written to the output-iterator. Before returning, all the input 72 processed will be deleted from the string <span class="emphasis"><em>s</em></span> (if <span class="emphasis"><em>max_split</em></span> 73 is not reached then all of <span class="emphasis"><em>s</em></span> will be deleted). Returns 74 the number of strings written to the output-iterator. If the parameter 75 <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, 76 then it defaults to "\s+", and splitting occurs on whitespace. 77 </p> 78<p> 79 <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> 80 if the complexity of matching the expression against an N character string 81 begins to exceed O(N<sup>2</sup>), or if the program runs out of stack space while 82 matching the expression (if Boost.Regex is configured in recursive mode), 83 or if the matcher exhausts its permitted memory allocation (if Boost.Regex 84 is configured in non-recursive mode). 85 </p> 86<p> 87 <span class="bold"><strong>Example</strong></span>: the following function will split 88 the input string into a series of tokens, and remove each token from the 89 string <span class="emphasis"><em>s</em></span>: 90 </p> 91<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> 92<span class="special">{</span> 93 <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> 94<span class="special">}</span> 95</pre> 96<p> 97 Example: the following short program will extract all of the URL's from 98 a html file, and print them out to cout: 99 </p> 100<pre class="programlisting"><span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">list</span><span class="special">></span> 101<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">fstream</span><span class="special">></span> 102<span class="preprocessor">#include</span> <span class="special"><</span><span class="identifier">iostream</span><span class="special">></span> 103<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> 104 105<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> 106 <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> 107 108<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> 109<span class="special">{</span> 110 <span class="identifier">s</span><span class="special">.</span><span class="identifier">erase</span><span class="special">();</span> 111 <span class="comment">//</span> 112 <span class="comment">// attempt to grow string buffer to match file size,</span> 113 <span class="comment">// this doesn't always work...</span> 114 <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> 115 <span class="keyword">char</span> <span class="identifier">c</span><span class="special">;</span> 116 <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> 117 <span class="special">{</span> 118 <span class="comment">// use logarithmic growth strategy, in case</span> 119 <span class="comment">// in_avail (above) returned zero:</span> 120 <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> 121 <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> 122 <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> 123 <span class="special">}</span> 124<span class="special">}</span> 125 126 127<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> 128<span class="special">{</span> 129 <span class="identifier">std</span><span class="special">::</span><span class="identifier">string</span> <span class="identifier">s</span><span class="special">;</span> 130 <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> 131 132 <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> 133 <span class="special">{</span> 134 <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> 135 <span class="identifier">s</span><span class="special">.</span><span class="identifier">erase</span><span class="special">();</span> 136 <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> 137 <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> 138 <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> 139 <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> 140 <span class="special">{</span> 141 <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> 142 <span class="identifier">l</span><span class="special">.</span><span class="identifier">pop_front</span><span class="special">();</span> 143 <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> 144 <span class="special">}</span> 145 <span class="special">}</span> 146 <span class="keyword">return</span> <span class="number">0</span><span class="special">;</span> 147<span class="special">}</span> 148</pre> 149</div> 150<table xmlns:rev="http://www.cs.rpi.edu/~gregod/boost/tools/doc/revision" width="100%"><tr> 151<td align="left"></td> 152<td align="right"><div class="copyright-footer">Copyright © 1998-2013 John Maddock<p> 153 Distributed under the Boost Software License, Version 1.0. (See accompanying 154 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>) 155 </p> 156</div></td> 157</tr></table> 158<hr> 159<div class="spirit-nav"> 160<a accesskey="p" href="regex_grep.html"><img src="../../../../../../../doc/src/images/prev.png" alt="Prev"></a><a accesskey="u" href="../deprecated.html"><img src="../../../../../../../doc/src/images/up.png" alt="Up"></a><a accesskey="h" href="../../../index.html"><img src="../../../../../../../doc/src/images/home.png" alt="Home"></a><a accesskey="n" href="old_regex.html"><img src="../../../../../../../doc/src/images/next.png" alt="Next"></a> 161</div> 162</body> 163</html> 164
