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/Src/Dependencies/Boost/boost/iostreams/read.hpp

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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#ifndef BOOST_IOSTREAMS_READ_HPP_INCLUDED
  9#define BOOST_IOSTREAMS_READ_HPP_INCLUDED
 10
 11#if defined(_MSC_VER) && (_MSC_VER >= 1020)
 12# pragma once
 13#endif
 14
 15#include <boost/config.hpp>  // DEDUCED_TYPENAME, MSVC.
 16#include <boost/detail/workaround.hpp>
 17#include <boost/iostreams/char_traits.hpp>
 18#include <boost/iostreams/detail/char_traits.hpp>
 19#include <boost/iostreams/detail/dispatch.hpp>
 20#include <boost/iostreams/detail/ios.hpp>  // streamsize.
 21#include <boost/iostreams/detail/streambuf.hpp>
 22#include <boost/iostreams/detail/wrap_unwrap.hpp>
 23#include <boost/iostreams/operations_fwd.hpp>
 24#include <boost/mpl/if.hpp>
 25
 26// Must come last.
 27#include <boost/iostreams/detail/config/disable_warnings.hpp>
 28
 29#if BOOST_WORKAROUND(BOOST_MSVC, < 1300) //-----------------------------------//
 30# include <boost/iostreams/detail/vc6/read.hpp>
 31#else // #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) //--------------------------//
 32
 33namespace boost { namespace iostreams {
 34
 35namespace detail {
 36
 37template<typename T>
 38struct read_device_impl;
 39
 40template<typename T>
 41struct read_filter_impl;
 42
 43} // End namespace detail.
 44
 45template<typename T>
 46typename int_type_of<T>::type get(T& t)
 47{ return detail::read_device_impl<T>::get(detail::unwrap(t)); }
 48
 49template<typename T>
 50inline std::streamsize
 51read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
 52{ return detail::read_device_impl<T>::read(detail::unwrap(t), s, n); }
 53
 54template<typename T, typename Source>
 55std::streamsize
 56read(T& t, Source& src, typename char_type_of<T>::type* s, std::streamsize n)
 57{ return detail::read_filter_impl<T>::read(detail::unwrap(t), src, s, n); }
 58
 59template<typename T>
 60bool putback(T& t, typename char_type_of<T>::type c)
 61{ return detail::read_device_impl<T>::putback(detail::unwrap(t), c); }
 62
 63//----------------------------------------------------------------------------//
 64
 65namespace detail {
 66
 67// Helper function for adding -1 as EOF indicator.
 68inline std::streamsize check_eof(std::streamsize n) { return n != 0 ? n : -1; }
 69
 70// Helper templates for reading from streambufs.
 71template<bool IsLinked>
 72struct true_eof_impl;
 73
 74template<>
 75struct true_eof_impl<true> {
 76    template<typename T>
 77    static bool true_eof(T& t) { return t.true_eof(); }
 78};
 79
 80template<>
 81struct true_eof_impl<false> {
 82    template<typename T>
 83    static bool true_eof(T&) { return true; }
 84};
 85
 86template<typename T>
 87inline bool true_eof(T& t)
 88{
 89    const bool linked = is_linked<T>::value;
 90    return true_eof_impl<linked>::true_eof(t);
 91}
 92
 93//------------------Definition of read_device_impl----------------------------//
 94
 95template<typename T>
 96struct read_device_impl
 97    : mpl::if_<
 98          detail::is_custom<T>,
 99          operations<T>,
100          read_device_impl<
101              BOOST_DEDUCED_TYPENAME
102              detail::dispatch<
103                  T, istream_tag, streambuf_tag, input
104              >::type
105          >
106      >::type
107    { };
108
109template<>
110struct read_device_impl<istream_tag> {
111    template<typename T>
112    static typename int_type_of<T>::type get(T& t)
113    { return t.get(); }
114
115    template<typename T>
116    static std::streamsize
117    read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
118    { return check_eof(t.rdbuf()->sgetn(s, n)); }
119
120    template<typename T>
121    static bool putback(T& t, typename char_type_of<T>::type c)
122    {
123        typedef typename char_type_of<T>::type          char_type;
124        typedef BOOST_IOSTREAMS_CHAR_TRAITS(char_type)  traits_type;
125        return !traits_type::eq_int_type( t.rdbuf()->sputbackc(c),
126                                          traits_type::eof() );
127    }
128};
129
130template<>
131struct read_device_impl<streambuf_tag> {
132    template<typename T>
133    static typename int_type_of<T>::type
134    get(T& t)
135    {   // gcc 2.95 needs namespace qualification for char_traits.
136        typedef typename char_type_of<T>::type     char_type;
137        typedef iostreams::char_traits<char_type>  traits_type;
138        typename int_type_of<T>::type c;
139        return !traits_type::is_eof(c = t.sbumpc()) ||
140                detail::true_eof(t)
141                    ?
142                c : traits_type::would_block();
143    }
144
145    template<typename T>
146    static std::streamsize
147    read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
148    {
149        std::streamsize amt;
150        return (amt = t.sgetn(s, n)) != 0 ?
151            amt :
152            detail::true_eof(t) ?
153                -1 :
154                0;
155    }
156
157    template<typename T>
158    static bool putback(T& t, typename char_type_of<T>::type c)
159    {   // gcc 2.95 needs namespace qualification for char_traits.
160        typedef typename char_type_of<T>::type     char_type;
161        typedef iostreams::char_traits<char_type>  traits_type;
162        return !traits_type::is_eof(t.sputbackc(c));
163    }
164};
165
166template<>
167struct read_device_impl<input> {
168    template<typename T>
169    static typename int_type_of<T>::type
170    get(T& t)
171    {   // gcc 2.95 needs namespace qualification for char_traits.
172        typedef typename char_type_of<T>::type     char_type;
173        typedef iostreams::char_traits<char_type>  traits_type;
174        char_type c;
175        std::streamsize amt;
176        return (amt = t.read(&c, 1)) == 1 ?
177            traits_type::to_int_type(c) :
178            amt == -1 ?
179                traits_type::eof() :
180                traits_type::would_block();
181    }
182
183    template<typename T>
184    static std::streamsize
185    read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
186    { return t.read(s, n); }
187
188    template<typename T>
189    static bool putback(T& t, typename char_type_of<T>::type c)
190    {   // T must be Peekable.
191        return t.putback(c);
192    }
193};
194
195//------------------Definition of read_filter_impl----------------------------//
196
197template<typename T>
198struct read_filter_impl
199    : mpl::if_<
200          detail::is_custom<T>,
201          operations<T>,
202          read_filter_impl<
203              BOOST_DEDUCED_TYPENAME
204              detail::dispatch<
205                  T, multichar_tag, any_tag
206              >::type
207          >
208      >::type
209    { };
210
211template<>
212struct read_filter_impl<multichar_tag> {
213    template<typename T, typename Source>
214    static std::streamsize read
215       (T& t, Source& src, typename char_type_of<T>::type* s, std::streamsize n)
216    { return t.read(src, s, n); }
217};
218
219template<>
220struct read_filter_impl<any_tag> {
221    template<typename T, typename Source>
222    static std::streamsize read
223       (T& t, Source& src, typename char_type_of<T>::type* s, std::streamsize n)
224    {   // gcc 2.95 needs namespace qualification for char_traits.
225        typedef typename char_type_of<T>::type     char_type;
226        typedef iostreams::char_traits<char_type>  traits_type;
227        for (std::streamsize off = 0; off < n; ++off) {
228            typename traits_type::int_type c = t.get(src);
229            if (traits_type::is_eof(c))
230                return check_eof(off);
231            if (traits_type::would_block(c))
232                return off;
233            s[off] = traits_type::to_char_type(c);
234        }
235        return n;
236    }
237};
238
239} // End namespace detail.
240
241} } // End namespaces iostreams, boost.
242
243#endif // #if BOOST_WORKAROUND(BOOST_MSVC, < 1300) //-------------------------//
244
245#include <boost/iostreams/detail/config/enable_warnings.hpp>
246
247#endif // #ifndef BOOST_IOSTREAMS_READ_HPP_INCLUDED