| // (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 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 |