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word_wrap.cpp
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1 /*******************************************************************************
2  * tlx/string/word_wrap.cpp
3  *
4  * Part of tlx - http://panthema.net/tlx
5  *
6  * Copyright (C) 2016-2017 Timo Bingmann <[email protected]>
7  *
8  * All rights reserved. Published under the Boost Software License, Version 1.0
9  ******************************************************************************/
10 
11 #include <tlx/string/word_wrap.hpp>
12 
13 #include <cctype>
14 
15 namespace tlx {
16 
17 bool is_space(char ch) {
18  return ch == ' ' || ch == '\f' || ch == '\t' ||
19  ch == '\r' || ch == '\n' || ch == '\v';
20 }
21 
22 std::string word_wrap(const std::string& str, unsigned int wrap) {
23  std::string out;
24  out.resize(str.size());
25 
26  std::string::size_type i = 0, last_space;
27 
28  while (i < str.size())
29  {
30  last_space = std::string::npos;
31 
32  // copy string until the end of the line is reached
33  for (std::string::size_type count = 0; count < wrap; ++count)
34  {
35  if (i == str.size()) {
36  // end of string reached
37  return out;
38  }
39 
40  out[i] = str[i];
41 
42  // check for newlines in input and reset counter
43  if (out[i] == '\n')
44  count = 0;
45  // save last space position
46  if (is_space(out[i]))
47  last_space = i;
48 
49  ++i;
50  }
51 
52  if (last_space != std::string::npos)
53  {
54  // turn last space into newline and step counter back
55  out[last_space] = '\n';
56 
57  if (i == str.size()) {
58  // end of string reached
59  return out;
60  }
61 
62  i = last_space + 1;
63  }
64  else
65  {
66  // no space in last line, copy until we find one
67  while (i != str.size() && !is_space(str[i]))
68  out[i] = str[i], ++i;
69 
70  if (i == str.size()) {
71  // end of string reached
72  return out;
73  }
74 
75  out[i] = '\n';
76  ++i;
77  }
78  }
79 
80  return out;
81 }
82 
83 } // namespace tlx
84 
85 /******************************************************************************/
std::string word_wrap(const std::string &str, unsigned int wrap)
Try to wrap a string to 80 columns without split words.
Definition: word_wrap.cpp:22
bool is_space(char ch)
Definition: word_wrap.cpp:17
std::basic_string< char, std::char_traits< char >, Allocator< char > > string
string with Manager tracking
Definition: allocator.hpp:220