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1 | // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com) |
2 | // (C) Copyright 2005-2007 Jonathan Turkanis | |
3 | // Distributed under the Boost Software License, Version 1.0. (See accompanying | |
4 | // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.) | |
5 | ||
6 | // See http://www.boost.org/libs/iostreams for documentation. | |
7 | ||
8 | // Adapted from an example of James Kanze, with suggestions from Rob Stewart. | |
9 | // See http://www.gabi-soft.fr/codebase-en.html. | |
10 | ||
11 | #ifndef BOOST_IOSTREAMS_TAB_EXPANDING_FILTER_HPP_INCLUDED | |
12 | #define BOOST_IOSTREAMS_TAB_EXPANDING_FILTER_HPP_INCLUDED | |
13 | ||
14 | #include <cassert> | |
15 | #include <cstdio> // EOF. | |
16 | #include <iostream> // cin, cout. | |
17 | #include <boost/iostreams/concepts.hpp> | |
18 | #include <boost/iostreams/filter/stdio.hpp> | |
19 | #include <boost/iostreams/operations.hpp> | |
20 | ||
21 | namespace boost { namespace iostreams { namespace example { | |
22 | ||
23 | class tab_expanding_stdio_filter : public stdio_filter { | |
24 | public: | |
25 | explicit tab_expanding_stdio_filter(int tab_size = 8) | |
26 | : tab_size_(tab_size), col_no_(0) | |
27 | { | |
28 | assert(tab_size > 0); | |
29 | } | |
30 | private: | |
31 | void do_filter() | |
32 | { | |
33 | int c; | |
34 | while ((c = std::cin.get()) != EOF) { | |
35 | if (c == '\t') { | |
36 | int spaces = tab_size_ - (col_no_ % tab_size_); | |
37 | for (; spaces > 0; --spaces) | |
38 | put_char(' '); | |
39 | } else { | |
40 | put_char(c); | |
41 | } | |
42 | } | |
43 | } | |
44 | void do_close() { col_no_ = 0; } | |
45 | void put_char(int c) | |
46 | { | |
47 | std::cout.put(c); | |
48 | if (c == '\n') { | |
49 | col_no_ = 0; | |
50 | } else { | |
51 | ++col_no_; | |
52 | } | |
53 | } | |
54 | int tab_size_; | |
55 | int col_no_; | |
56 | }; | |
57 | ||
58 | class tab_expanding_input_filter : public input_filter { | |
59 | public: | |
60 | explicit tab_expanding_input_filter(int tab_size = 8) | |
61 | : tab_size_(tab_size), col_no_(0), spaces_(0) | |
62 | { | |
63 | assert(tab_size > 0); | |
64 | } | |
65 | ||
66 | template<typename Source> | |
67 | int get(Source& src) | |
68 | { | |
69 | if (spaces_ > 0) { | |
70 | --spaces_; | |
71 | return get_char(' '); | |
72 | } | |
73 | ||
74 | int c; | |
75 | if ((c = iostreams::get(src)) == EOF || c == WOULD_BLOCK) | |
76 | return c; | |
77 | ||
78 | if (c != '\t') | |
79 | return get_char(c); | |
80 | ||
81 | // Found a tab. Call this filter recursively. | |
82 | spaces_ = tab_size_ - (col_no_ % tab_size_); | |
83 | return this->get(src); | |
84 | } | |
85 | ||
86 | template<typename Source> | |
87 | void close(Source&) | |
88 | { | |
89 | col_no_ = 0; | |
90 | spaces_ = 0; | |
91 | } | |
92 | private: | |
93 | int get_char(int c) | |
94 | { | |
95 | if (c == '\n') { | |
96 | col_no_ = 0; | |
97 | } else { | |
98 | ++col_no_; | |
99 | } | |
100 | return c; | |
101 | } | |
102 | int tab_size_; | |
103 | int col_no_; | |
104 | int spaces_; | |
105 | }; | |
106 | ||
107 | class tab_expanding_output_filter : public output_filter { | |
108 | public: | |
109 | explicit tab_expanding_output_filter(int tab_size = 8) | |
110 | : tab_size_(tab_size), col_no_(0), spaces_(0) | |
111 | { | |
112 | assert(tab_size > 0); | |
113 | } | |
114 | ||
115 | template<typename Sink> | |
116 | bool put(Sink& dest, int c) | |
117 | { | |
118 | for (; spaces_ > 0; --spaces_) | |
119 | if (!put_char(dest, ' ')) | |
120 | return false; | |
121 | ||
122 | if (c == '\t') { | |
123 | spaces_ = tab_size_ - (col_no_ % tab_size_) - 1; | |
124 | return this->put(dest, ' '); | |
125 | } | |
126 | ||
127 | return put_char(dest, c); | |
128 | } | |
129 | ||
130 | template<typename Sink> | |
131 | void close(Sink&) | |
132 | { | |
133 | col_no_ = 0; | |
134 | spaces_ = 0; | |
135 | } | |
136 | private: | |
137 | template<typename Sink> | |
138 | bool put_char(Sink& dest, int c) | |
139 | { | |
140 | if (!iostreams::put(dest, c)) | |
141 | return false; | |
142 | if (c != '\n') | |
143 | ++col_no_; | |
144 | else | |
145 | col_no_ = 0; | |
146 | return true; | |
147 | } | |
148 | int tab_size_; | |
149 | int col_no_; | |
150 | int spaces_; | |
151 | }; | |
152 | ||
153 | } } } // End namespaces example, iostreams, boost. | |
154 | ||
155 | #endif // #ifndef BOOST_IOSTREAMS_TAB_EXPANDING_FILTER_HPP_INCLUDED |