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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.
namespace boost { namespace iostreams {
namespace detail {
template<typename T>
struct read_device_impl;
template<typename T>
struct read_filter_impl;
} // End namespace detail.
template<typename T>
typename int_type_of<T>::type get(T& t)
{
typedef typename detail::unwrapped_type<T>::type unwrapped;
return detail::read_device_impl<T>::inner<unwrapped>::get(detail::unwrap(t));
}
template<typename T>
inline std::streamsize
read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
{
typedef typename detail::unwrapped_type<T>::type unwrapped;
return detail::read_device_impl<T>::inner<unwrapped>::read(detail::unwrap(t), s, n);
}
template<typename T, typename Source>
std::streamsize
read(T& t, Source& src, typename char_type_of<T>::type* s, std::streamsize n)
{
typedef typename detail::unwrapped_type<T>::type unwrapped;
return detail::read_filter_impl<T>::inner<unwrapped>::read(detail::unwrap(t), src, s, n);
}
template<typename T>
bool putback(T& t, typename char_type_of<T>::type c)
{
typedef typename detail::unwrapped_type<T>::type unwrapped;
return detail::read_device_impl<T>::inner<unwrapped>::putback(detail::unwrap(t), c);
}
//----------------------------------------------------------------------------//
namespace detail {
// Helper function for adding -1 as EOF indicator.
inline std::streamsize check_eof(std::streamsize n) { return n != 0 ? n : -1; }
// Helper templates for reading from streambufs.
template<bool IsLinked>
struct true_eof_impl;
template<>
struct true_eof_impl<true> {
template<typename T>
static bool true_eof(T& t) { return t.true_eof(); }
};
template<>
struct true_eof_impl<false> {
template<typename T>
static bool true_eof(T& t) { return true; }
};
template<typename T>
inline bool true_eof(T& t)
{
const bool linked = is_linked<T>::value;
return true_eof_impl<linked>::true_eof(t);
}
//------------------Definition of read_device_impl----------------------------//
template<typename T>
struct read_device_impl
: mpl::if_<
detail::is_custom<T>,
operations<T>,
read_device_impl<
BOOST_DEDUCED_TYPENAME
detail::dispatch<
T, istream_tag, streambuf_tag, input
>::type
>
>::type
{ };
template<>
struct read_device_impl<istream_tag> {
template<typename T>
struct inner {
static typename int_type_of<T>::type get(T& t)
{ return t.get(); }
static std::streamsize
read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
{ return check_eof(t.rdbuf()->sgetn(s, n)); }
static bool putback(T& t, typename char_type_of<T>::type c)
{
typedef typename char_type_of<T>::type char_type;
typedef BOOST_IOSTREAMS_CHAR_TRAITS(char_type) traits_type;
return !traits_type::eq_int_type( t.rdbuf()->sputbackc(c),
traits_type::eof() );
}
};
};
template<>
struct read_device_impl<streambuf_tag> {
template<typename T>
struct inner {
static typename int_type_of<T>::type
get(T& t)
{
typedef typename char_type_of<T>::type char_type;
typedef char_traits<char_type> traits_type;
typename int_type_of<T>::type c;
return !traits_type::is_eof(c = t.sbumpc()) ||
detail::true_eof(t)
?
c : traits_type::would_block();
}
static std::streamsize
read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
{
std::streamsize amt;
return (amt = t.sgetn(s, n)) != 0 ?
amt :
detail::true_eof(t) ?
-1 :
0;
}
static bool putback(T& t, typename char_type_of<T>::type c)
{
typedef typename char_type_of<T>::type char_type;
typedef char_traits<char_type> traits_type;
return !traits_type::is_eof(t.sputbackc(c));
}
};
};
template<>
struct read_device_impl<input> {
template<typename T>
struct inner {
static typename int_type_of<T>::type
get(T& t)
{
typedef typename char_type_of<T>::type char_type;
typedef char_traits<char_type> traits_type;
char_type c;
std::streamsize amt;
return (amt = t.read(&c, 1)) == 1 ?
traits_type::to_int_type(c) :
amt == -1 ?
traits_type::eof() :
traits_type::would_block();
}
template<typename T>
static std::streamsize
read(T& t, typename char_type_of<T>::type* s, std::streamsize n)
{ return t.read(s, n); }
template<typename T>
static bool putback(T& t, typename char_type_of<T>::type c)
{ // T must be Peekable.
return t.putback(c);
}
};
};
//------------------Definition of read_filter_impl----------------------------//
template<typename T>
struct read_filter_impl
: mpl::if_<
detail::is_custom<T>,
operations<T>,
read_filter_impl<
BOOST_DEDUCED_TYPENAME
detail::dispatch<
T, multichar_tag, any_tag
>::type
>
>::type
{ };
template<>
struct read_filter_impl<multichar_tag> {
template<typename T>
struct inner {
template<typename Source>
static std::streamsize read
( T& t, Source& src, typename char_type_of<T>::type* s,
std::streamsize n )
{ return t.read(src, s, n); }
};
};
template<>
struct read_filter_impl<any_tag> {
template<typename T>
struct inner {
template<typename Source>
static std::streamsize read
( T& t, Source& src, typename char_type_of<T>::type* s,
std::streamsize n )
{
typedef typename char_type_of<T>::type char_type;
typedef char_traits<char_type> traits_type;
for (std::streamsize off = 0; off < n; ++off) {
typename traits_type::int_type c = t.get(src);
if (traits_type::is_eof(c))
return check_eof(off);
if (traits_type::would_block(c))
return off;
s[off] = traits_type::to_char_type(c);
}
return n;
}
};
};
} // End namespace detail.
} } // End namespaces iostreams, boost.
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