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- // (C) Copyright 2008 CodeRage, LLC (turkanis at coderage dot com)
- // (C) Copyright 2005-2007 Jonathan Turkanis
- // Distributed under the Boost Software License, Version 1.0. (See accompanying
- // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt.)
- // See http://www.boost.org/libs/iostreams for documentation.
- // Adapted from an example of James Kanze, with suggestions from Rob Stewart.
- // See https://web.archive.org/web/20041222094942/http://www.gabi-soft.fr/codebase-en.html.
- #ifndef BOOST_IOSTREAMS_TAB_EXPANDING_FILTER_HPP_INCLUDED
- #define BOOST_IOSTREAMS_TAB_EXPANDING_FILTER_HPP_INCLUDED
- #include <cassert>
- #include <cstdio> // EOF.
- #include <iostream> // cin, cout.
- #include <boost/iostreams/concepts.hpp>
- #include <boost/iostreams/filter/stdio.hpp>
- #include <boost/iostreams/operations.hpp>
- namespace boost { namespace iostreams { namespace example {
- class tab_expanding_stdio_filter : public stdio_filter {
- public:
- explicit tab_expanding_stdio_filter(int tab_size = 8)
- : tab_size_(tab_size), col_no_(0)
- {
- assert(tab_size > 0);
- }
- private:
- void do_filter()
- {
- int c;
- while ((c = std::cin.get()) != EOF) {
- if (c == '\t') {
- int spaces = tab_size_ - (col_no_ % tab_size_);
- for (; spaces > 0; --spaces)
- put_char(' ');
- } else {
- put_char(c);
- }
- }
- }
- void do_close() { col_no_ = 0; }
- void put_char(int c)
- {
- std::cout.put(c);
- if (c == '\n') {
- col_no_ = 0;
- } else {
- ++col_no_;
- }
- }
- int tab_size_;
- int col_no_;
- };
- class tab_expanding_input_filter : public input_filter {
- public:
- explicit tab_expanding_input_filter(int tab_size = 8)
- : tab_size_(tab_size), col_no_(0), spaces_(0)
- {
- assert(tab_size > 0);
- }
- template<typename Source>
- int get(Source& src)
- {
- if (spaces_ > 0) {
- --spaces_;
- return get_char(' ');
- }
- int c;
- if ((c = iostreams::get(src)) == EOF || c == WOULD_BLOCK)
- return c;
- if (c != '\t')
- return get_char(c);
- // Found a tab. Call this filter recursively.
- spaces_ = tab_size_ - (col_no_ % tab_size_);
- return this->get(src);
- }
- template<typename Source>
- void close(Source&)
- {
- col_no_ = 0;
- spaces_ = 0;
- }
- private:
- int get_char(int c)
- {
- if (c == '\n') {
- col_no_ = 0;
- } else {
- ++col_no_;
- }
- return c;
- }
- int tab_size_;
- int col_no_;
- int spaces_;
- };
- class tab_expanding_output_filter : public output_filter {
- public:
- explicit tab_expanding_output_filter(int tab_size = 8)
- : tab_size_(tab_size), col_no_(0), spaces_(0)
- {
- assert(tab_size > 0);
- }
- template<typename Sink>
- bool put(Sink& dest, int c)
- {
- for (; spaces_ > 0; --spaces_)
- if (!put_char(dest, ' '))
- return false;
- if (c == '\t') {
- spaces_ = tab_size_ - (col_no_ % tab_size_) - 1;
- return this->put(dest, ' ');
- }
- return put_char(dest, c);
- }
- template<typename Sink>
- void close(Sink&)
- {
- col_no_ = 0;
- spaces_ = 0;
- }
- private:
- template<typename Sink>
- bool put_char(Sink& dest, int c)
- {
- if (!iostreams::put(dest, c))
- return false;
- if (c != '\n')
- ++col_no_;
- else
- col_no_ = 0;
- return true;
- }
- int tab_size_;
- int col_no_;
- int spaces_;
- };
- } } } // End namespaces example, iostreams, boost.
- #endif // #ifndef BOOST_IOSTREAMS_TAB_EXPANDING_FILTER_HPP_INCLUDED
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