1<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"> 2 3<html> 4<head> 5 <meta http-equiv="Content-Language" content="en-us"> 6 <meta http-equiv="Content-Type" content="text/html; charset=us-ascii"> 7 <meta name="GENERATOR" content="Microsoft FrontPage 6.0"> 8 <meta name="ProgId" content="FrontPage.Editor.Document"> 9 10 <title>Boost Offset Separator</title> 11</head> 12 13<body bgcolor="#FFFFFF" text="#000000" link="#0000EE" vlink="#551A8B" alink= 14"#FF0000"> 15 <p><img src="../../../boost.png" alt="C++ Boost" width="277" height= 16 "86"><br></p> 17 18 <h1 align="center">Offset Separator</h1> 19 <pre> 20class offset_separator 21</pre> 22 23 <p>The <tt>offset_separator</tt> class is an implementation of the <a href= 24 "tokenizerfunction.htm">TokenizerFunction</a> concept that can be used with 25 the <a href="tokenizer.htm">tokenizer</a> class to break text up into 26 tokens. The <tt>offset_separator</tt> breaks a sequence of <tt>Char</tt>'s 27 into strings based on a sequence of offsets. For example, if you had the 28 string "12252001" and offsets (2,2,4) it would break the string into 12 25 29 2001. Here is an example.</p> 30 31 <h2>Example</h2> 32 <pre> 33// simple_example_3.cpp 34#include<iostream> 35#include<boost/tokenizer.hpp> 36#include<string> 37 38int main(){ 39 using namespace std; 40 using namespace boost; 41 string s = "12252001"; 42 int offsets[] = {2,2,4}; 43 offset_separator f(offsets, offsets+3); 44 tokenizer<offset_separator> tok(s,f); 45 for(tokenizer<offset_separator>::iterator beg=tok.begin(); beg!=tok.end();++beg){ 46 cout << *beg << "\n"; 47 } 48} 49</pre> 50 51 <p> </p> 52 53 <h2>Construction and Usage</h2> 54 55 <p>The offset_separator has 1 constructor of interest. (The default 56 constructor is just there to make some compilers happy). The declaration is 57 below</p> 58 <pre> 59template<typename Iter> 60offset_separator(Iter begin,Iter end,bool bwrapoffsets = true, bool breturnpartiallast = true) 61</pre> 62 63 <table border="1" summary=""> 64 <tr> 65 <td> 66 <p align="center"><strong>Parameter</strong></p> 67 </td> 68 69 <td> 70 <p align="center"><strong>Description</strong></p> 71 </td> 72 </tr> 73 74 <tr> 75 <td>begin, end</td> 76 77 <td>Specify the sequence of integer offsets.</td> 78 </tr> 79 80 <tr> 81 <td>bwrapoffsets</td> 82 83 <td>Tells whether to wrap around to the beginning of the offsets when 84 the all the offsets have been used. For example the string 85 "1225200101012002" with offsets (2,2,4) with bwrapoffsets to true, 86 would parse to 12 25 2001 01 01 2002. With bwrapoffsets to false, it 87 would parse to 12 25 2001 and then stop because all the offsets have 88 been used.</td> 89 </tr> 90 91 <tr> 92 <td>breturnpartiallast</td> 93 94 <td>Tells whether, when the parsed sequence terminates before yielding 95 the number of characters in the current offset, to create a token with 96 what was parsed, or to ignore it. For example the string "122501" with 97 offsets (2,2,4) with breturnpartiallast set to true will parse to 12 25 98 01. With it set to false, it will parse to 12 25 and then will stop 99 because there are only 2 characters left in the sequence instead of the 100 4 that should have been there.</td> 101 </tr> 102 </table> 103 104 <p>To use this class, pass an object of it anywhere a TokenizerFunction is 105 required. If you default constructruct the object, it will just return 106 every character in the parsed sequence as a token. (ie it defaults to an 107 offset of 1, and bwrapoffsets is true).</p> 108 109 <p> </p> 110 111 <h2>Model of</h2> 112 113 <p><a href="tokenizerfunction.htm">TokenizerFunction</a></p> 114 <hr> 115 116 <p><a href="http://validator.w3.org/check?uri=referer"><img border="0" src= 117 "../../doc/images/valid-html401.png" alt="Valid HTML 4.01 Transitional" 118 height="31" width="88"></a></p> 119 120 <p>Revised 121 <!--webbot bot="Timestamp" s-type="EDITED" s-format="%d %B, %Y" startspan -->25 122 December, 2006<!--webbot bot="Timestamp" endspan i-checksum="38518" --></p> 123 124 <p><i>Copyright © 2001 John R. Bandela</i></p> 125 126 <p><i>Distributed under the Boost Software License, Version 1.0. (See 127 accompanying file <a href="../../LICENSE_1_0.txt">LICENSE_1_0.txt</a> or 128 copy at <a href= 129 "http://www.boost.org/LICENSE_1_0.txt">http://www.boost.org/LICENSE_1_0.txt</a>)</i></p> 130</body> 131</html> 132
