boost/tuple/tuple_io.hpp
// tuple_io.hpp --------------------------------------------------------------
// Copyright (C) 2001 Jaakko Jarvi (jaakko.jarvi@cs.utu.fi)
// 2001 Gary Powell (gary.powell@sierra.com)
//
// 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)
// For more information, see http://www.boost.org
// ----------------------------------------------------------------------------
#ifndef BOOST_TUPLE_IO_HPP
#define BOOST_TUPLE_IO_HPP
#include <istream>
#include <ostream>
#include <sstream>
#include <boost/tuple/tuple.hpp>
// This is ugly: one should be using twoargument isspace since whitspace can
// be locale dependent, in theory at least.
// not all libraries implement have the two-arg version, so we need to
// use the one-arg one, which one should get with <cctype> but there seem
// to be exceptions to this.
#if !defined (BOOST_NO_STD_LOCALE)
#include <locale> // for two-arg isspace
#else
#include <cctype> // for one-arg (old) isspace
#include <ctype.h> // Metrowerks does not find one-arg isspace from cctype
#endif
namespace boost {
namespace tuples {
namespace detail {
class format_info {
public:
enum manipulator_type { open, close, delimiter };
BOOST_STATIC_CONSTANT(int, number_of_manipulators = delimiter + 1);
private:
static int get_stream_index (int m)
{
static const int stream_index[number_of_manipulators]
= { std::ios::xalloc(), std::ios::xalloc(), std::ios::xalloc() };
return stream_index[m];
}
format_info(const format_info&);
format_info();
public:
template<class CharType, class CharTrait>
static CharType get_manipulator(std::basic_ios<CharType, CharTrait>& i,
manipulator_type m) {
// The manipulators are stored as long.
// A valid instanitation of basic_stream allows CharType to be any POD,
// hence, the static_cast may fail (it fails if long is not convertible
// to CharType
CharType c = static_cast<CharType>(i.iword(get_stream_index(m)) );
// parentheses and space are the default manipulators
if (!c) {
switch(m) {
case detail::format_info::open : c = i.widen('('); break;
case detail::format_info::close : c = i.widen(')'); break;
case detail::format_info::delimiter : c = i.widen(' '); break;
}
}
return c;
}
template<class CharType, class CharTrait>
static void set_manipulator(std::basic_ios<CharType, CharTrait>& i,
manipulator_type m, CharType c) {
// The manipulators are stored as long.
// A valid instanitation of basic_stream allows CharType to be any POD,
// hence, the static_cast may fail (it fails if CharType is not
// convertible long.
i.iword(get_stream_index(m)) = static_cast<long>(c);
}
};
} // end of namespace detail
template<class CharType>
class tuple_manipulator {
const detail::format_info::manipulator_type mt;
CharType f_c;
public:
explicit tuple_manipulator(detail::format_info::manipulator_type m,
CharType c = CharType())
: mt(m), f_c(c) {}
template<class CharTrait>
void set(std::basic_ios<CharType, CharTrait> &io) const {
detail::format_info::set_manipulator(io, mt, f_c);
}
};
template<class CharType, class CharTrait>
inline std::basic_ostream<CharType, CharTrait>&
operator<<(std::basic_ostream<CharType, CharTrait>& o, const tuple_manipulator<CharType>& m) {
m.set(o);
return o;
}
template<class CharType, class CharTrait>
inline std::basic_istream<CharType, CharTrait>&
operator>>(std::basic_istream<CharType, CharTrait>& i, const tuple_manipulator<CharType>& m) {
m.set(i);
return i;
}
template<class CharType>
inline tuple_manipulator<CharType> set_open(const CharType c) {
return tuple_manipulator<CharType>(detail::format_info::open, c);
}
template<class CharType>
inline tuple_manipulator<CharType> set_close(const CharType c) {
return tuple_manipulator<CharType>(detail::format_info::close, c);
}
template<class CharType>
inline tuple_manipulator<CharType> set_delimiter(const CharType c) {
return tuple_manipulator<CharType>(detail::format_info::delimiter, c);
}
// -------------------------------------------------------------
// printing tuples to ostream in format (a b c)
// parentheses and space are defaults, but can be overriden with manipulators
// set_open, set_close and set_delimiter
namespace detail {
// Note: The order of the print functions is critical
// to let a conforming compiler find and select the correct one.
template<class CharType, class CharTrait, class T1>
inline std::basic_ostream<CharType, CharTrait>&
print(std::basic_ostream<CharType, CharTrait>& o, const cons<T1, null_type>& t) {
return o << t.head;
}
template<class CharType, class CharTrait>
inline std::basic_ostream<CharType, CharTrait>&
print(std::basic_ostream<CharType, CharTrait>& o, const null_type&) {
return o;
}
template<class CharType, class CharTrait, class T1, class T2>
inline std::basic_ostream<CharType, CharTrait>&
print(std::basic_ostream<CharType, CharTrait>& o, const cons<T1, T2>& t) {
const CharType d = format_info::get_manipulator(o, format_info::delimiter);
o << t.head;
o << d;
return print(o, t.tail);
}
template<class CharT, class Traits, class T>
inline bool handle_width(std::basic_ostream<CharT, Traits>& o, const T& t) {
std::streamsize width = o.width();
if(width == 0) return false;
std::basic_ostringstream<CharT, Traits> ss;
ss.copyfmt(o);
ss.tie(0);
ss.width(0);
ss << t;
o << ss.str();
return true;
}
} // namespace detail
template<class CharType, class CharTrait>
inline std::basic_ostream<CharType, CharTrait>&
operator<<(std::basic_ostream<CharType, CharTrait>& o,
const null_type& t) {
if (!o.good() ) return o;
if (detail::handle_width(o, t)) return o;
const CharType l =
detail::format_info::get_manipulator(o, detail::format_info::open);
const CharType r =
detail::format_info::get_manipulator(o, detail::format_info::close);
o << l;
o << r;
return o;
}
template<class CharType, class CharTrait, class T1, class T2>
inline std::basic_ostream<CharType, CharTrait>&
operator<<(std::basic_ostream<CharType, CharTrait>& o,
const cons<T1, T2>& t) {
if (!o.good() ) return o;
if (detail::handle_width(o, t)) return o;
const CharType l =
detail::format_info::get_manipulator(o, detail::format_info::open);
const CharType r =
detail::format_info::get_manipulator(o, detail::format_info::close);
o << l;
detail::print(o, t);
o << r;
return o;
}
// -------------------------------------------------------------
// input stream operators
namespace detail {
template<class CharType, class CharTrait>
inline std::basic_istream<CharType, CharTrait>&
extract_and_check_delimiter(
std::basic_istream<CharType, CharTrait> &is, format_info::manipulator_type del)
{
const CharType d = format_info::get_manipulator(is, del);
#if defined (BOOST_NO_STD_LOCALE)
const bool is_delimiter = !isspace(d);
#elif defined ( BOOST_BORLANDC )
const bool is_delimiter = !std::use_facet< std::ctype< CharType > >
(is.getloc() ).is( std::ctype_base::space, d);
#else
const bool is_delimiter = (!std::isspace(d, is.getloc()) );
#endif
CharType c;
if (is_delimiter) {
is >> c;
if (is.good() && c!=d) {
is.setstate(std::ios::failbit);
}
} else {
is >> std::ws;
}
return is;
}
template<class CharType, class CharTrait, class T1>
inline std::basic_istream<CharType, CharTrait> &
read (std::basic_istream<CharType, CharTrait> &is, cons<T1, null_type>& t1) {
if (!is.good()) return is;
return is >> t1.head;
}
template<class CharType, class CharTrait, class T1, class T2>
inline std::basic_istream<CharType, CharTrait>&
read(std::basic_istream<CharType, CharTrait> &is, cons<T1, T2>& t1) {
if (!is.good()) return is;
is >> t1.head;
extract_and_check_delimiter(is, format_info::delimiter);
return read(is, t1.tail);
}
} // end namespace detail
template<class CharType, class CharTrait>
inline std::basic_istream<CharType, CharTrait>&
operator>>(std::basic_istream<CharType, CharTrait> &is, null_type&) {
if (!is.good() ) return is;
detail::extract_and_check_delimiter(is, detail::format_info::open);
detail::extract_and_check_delimiter(is, detail::format_info::close);
return is;
}
template<class CharType, class CharTrait, class T1, class T2>
inline std::basic_istream<CharType, CharTrait>&
operator>>(std::basic_istream<CharType, CharTrait>& is, cons<T1, T2>& t1) {
if (!is.good() ) return is;
detail::extract_and_check_delimiter(is, detail::format_info::open);
detail::read(is, t1);
detail::extract_and_check_delimiter(is, detail::format_info::close);
return is;
}
} // end of namespace tuples
} // end of namespace boost
#endif // BOOST_TUPLE_IO_HPP