boost/spirit/home/karma/directive/center_alignment.hpp
// Copyright (c) 2001-2011 Hartmut Kaiser
//
// 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)
#if !defined(BOOST_SPIRIT_KARMA_CENTER_ALIGNMENT_FEB_27_2007_1216PM)
#define BOOST_SPIRIT_KARMA_CENTER_ALIGNMENT_FEB_27_2007_1216PM
#if defined(_MSC_VER)
#pragma once
#endif
#include <boost/spirit/home/karma/meta_compiler.hpp>
#include <boost/spirit/home/karma/generator.hpp>
#include <boost/spirit/home/karma/domain.hpp>
#include <boost/spirit/home/karma/detail/output_iterator.hpp>
#include <boost/spirit/home/karma/detail/default_width.hpp>
#include <boost/spirit/home/karma/delimit_out.hpp>
#include <boost/spirit/home/karma/auxiliary/lazy.hpp>
#include <boost/spirit/home/karma/char/char.hpp>
#include <boost/spirit/home/support/unused.hpp>
#include <boost/spirit/home/support/common_terminals.hpp>
#include <boost/spirit/home/support/has_semantic_action.hpp>
#include <boost/spirit/home/support/handles_container.hpp>
#include <boost/spirit/home/karma/detail/attributes.hpp>
#include <boost/spirit/home/support/info.hpp>
#include <boost/spirit/home/support/unused.hpp>
#include <boost/fusion/include/at.hpp>
#include <boost/fusion/include/vector.hpp>
#include <boost/integer_traits.hpp>
#include <boost/mpl/bool.hpp>
#include <boost/utility/enable_if.hpp>
#include <boost/detail/workaround.hpp>
///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit
{
///////////////////////////////////////////////////////////////////////////
// Enablers
///////////////////////////////////////////////////////////////////////////
// enables center[]
template <>
struct use_directive<karma::domain, tag::center>
: mpl::true_ {};
// enables center(d)[g] and center(w)[g], where d is a generator
// and w is a maximum width
template <typename T>
struct use_directive<karma::domain
, terminal_ex<tag::center, fusion::vector1<T> > >
: mpl::true_ {};
// enables *lazy* center(d)[g], where d provides a generator
template <>
struct use_lazy_directive<karma::domain, tag::center, 1>
: mpl::true_ {};
// enables center(w, d)[g], where d is a generator and w is a maximum
// width
template <typename Width, typename Padding>
struct use_directive<karma::domain
, terminal_ex<tag::center, fusion::vector2<Width, Padding> > >
: spirit::traits::matches<karma::domain, Padding> {};
// enables *lazy* center(w, d)[g], where d provides a generator and w is
// a maximum width
template <>
struct use_lazy_directive<karma::domain, tag::center, 2>
: mpl::true_ {};
}}
///////////////////////////////////////////////////////////////////////////////
namespace boost { namespace spirit { namespace karma
{
#ifndef BOOST_SPIRIT_NO_PREDEFINED_TERMINALS
using spirit::center;
#endif
using spirit::center_type;
namespace detail
{
///////////////////////////////////////////////////////////////////////
// The center_generate template function is used for all the
// different flavors of the center[] directive.
///////////////////////////////////////////////////////////////////////
template <typename OutputIterator, typename Context, typename Delimiter,
typename Attribute, typename Embedded, typename Padding>
inline static bool
center_generate(OutputIterator& sink, Context& ctx,
Delimiter const& d, Attribute const& attr, Embedded const& e,
unsigned int const width, Padding const& p)
{
#if BOOST_WORKAROUND(BOOST_MSVC, BOOST_TESTED_AT(1600))
(void)e; // suppresses warning: C4100: 'e' : unreferenced formal parameter
#endif
// wrap the given output iterator to allow left padding
detail::enable_buffering<OutputIterator> buffering(sink, width);
bool r = false;
// first generate the embedded output
{
detail::disable_counting<OutputIterator> nocounting(sink);
r = e.generate(sink, ctx, d, attr);
} // re-enable counting
buffering.disable(); // do not perform buffering any more
// generate the left padding
detail::enable_counting<OutputIterator> counting(sink);
std::size_t const pre = width - (buffering.buffer_size() + width)/2;
while (r && counting.count() < pre)
r = p.generate(sink, ctx, unused, unused);
if (r) {
// copy the embedded output to the target output iterator
buffering.buffer_copy();
// generate the right padding
while (r && counting.count() < width)
r = p.generate(sink, ctx, unused, unused);
}
return r;
}
}
///////////////////////////////////////////////////////////////////////////
// The simple left alignment directive is used for center[...]
// generators. It uses default values for the generated width (defined via
// the BOOST_KARMA_DEFAULT_FIELD_LENGTH constant) and for the padding
// generator (always spaces).
///////////////////////////////////////////////////////////////////////////
template <typename Subject, typename Width = detail::default_width>
struct simple_center_alignment
: unary_generator<simple_center_alignment<Subject, Width> >
{
typedef Subject subject_type;
typedef mpl::int_<
generator_properties::countingbuffer | subject_type::properties::value
> properties;
template <typename Context, typename Iterator>
struct attribute
: traits::attribute_of<subject_type, Context, Iterator>
{};
simple_center_alignment(Subject const& subject, Width width = Width())
: subject(subject), width(width) {}
template <typename OutputIterator, typename Context, typename Delimiter
, typename Attribute>
bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
, Attribute const& attr) const
{
return detail::center_generate(sink, ctx, d, attr,
subject, width, compile<karma::domain>(' '));
}
template <typename Context>
info what(Context& context) const
{
return info("center", subject.what(context));
}
Subject subject;
Width width;
};
///////////////////////////////////////////////////////////////////////////
// The left alignment directive with padding, is used for generators like
// center(padding)[...], where padding is a arbitrary generator
// expression. It uses a default value for the generated width (defined
// via the BOOST_KARMA_DEFAULT_FIELD_LENGTH constant).
///////////////////////////////////////////////////////////////////////////
template <typename Subject, typename Padding
, typename Width = detail::default_width>
struct padding_center_alignment
: unary_generator<padding_center_alignment<Subject, Padding, Width> >
{
typedef Subject subject_type;
typedef Padding padding_type;
typedef mpl::int_<
generator_properties::countingbuffer |
subject_type::properties::value | padding_type::properties::value
> properties;
template <typename Context, typename Iterator>
struct attribute
: traits::attribute_of<Subject, Context, Iterator>
{};
padding_center_alignment(Subject const& subject, Padding const& padding
, Width width = Width())
: subject(subject), padding(padding), width(width) {}
template <typename OutputIterator, typename Context, typename Delimiter
, typename Attribute>
bool generate(OutputIterator& sink, Context& ctx, Delimiter const& d
, Attribute const& attr) const
{
return detail::center_generate(sink, ctx, d, attr,
subject, width, padding);
}
template <typename Context>
info what(Context& context) const
{
return info("center", subject.what(context));
}
Subject subject;
Padding padding;
Width width;
};
///////////////////////////////////////////////////////////////////////////
// Generator generators: make_xxx function (objects)
///////////////////////////////////////////////////////////////////////////
// creates center[] directive generator
template <typename Subject, typename Modifiers>
struct make_directive<tag::center, Subject, Modifiers>
{
typedef simple_center_alignment<Subject> result_type;
result_type operator()(unused_type, Subject const& subject
, unused_type) const
{
return result_type(subject);
}
};
// creates center(width)[] directive generator
template <typename Width, typename Subject, typename Modifiers>
struct make_directive<
terminal_ex<tag::center, fusion::vector1<Width> >
, Subject, Modifiers
, typename enable_if_c< integer_traits<Width>::is_integral >::type>
{
typedef simple_center_alignment<Subject, Width> result_type;
template <typename Terminal>
result_type operator()(Terminal const& term, Subject const& subject
, unused_type) const
{
return result_type(subject, fusion::at_c<0>(term.args));
}
};
// creates center(pad)[] directive generator
template <typename Padding, typename Subject, typename Modifiers>
struct make_directive<
terminal_ex<tag::center, fusion::vector1<Padding> >
, Subject, Modifiers
, typename enable_if<
mpl::and_<
spirit::traits::matches<karma::domain, Padding>,
mpl::not_<mpl::bool_<integer_traits<Padding>::is_integral> >
>
>::type>
{
typedef typename
result_of::compile<karma::domain, Padding, Modifiers>::type
padding_type;
typedef padding_center_alignment<Subject, padding_type> result_type;
template <typename Terminal>
result_type operator()(Terminal const& term, Subject const& subject
, Modifiers const& modifiers) const
{
return result_type(subject
, compile<karma::domain>(fusion::at_c<0>(term.args), modifiers));
}
};
// creates center(width, pad)[] directive generator
template <typename Width, typename Padding, typename Subject
, typename Modifiers>
struct make_directive<
terminal_ex<tag::center, fusion::vector2<Width, Padding> >
, Subject, Modifiers>
{
typedef typename
result_of::compile<karma::domain, Padding, Modifiers>::type
padding_type;
typedef padding_center_alignment<Subject, padding_type, Width> result_type;
template <typename Terminal>
result_type operator()(Terminal const& term, Subject const& subject
, Modifiers const& modifiers) const
{
return result_type(subject
, compile<karma::domain>(fusion::at_c<1>(term.args), modifiers)
, fusion::at_c<0>(term.args));
}
};
}}} // namespace boost::spirit::karma
namespace boost { namespace spirit { namespace traits
{
///////////////////////////////////////////////////////////////////////////
template <typename Subject, typename Width>
struct has_semantic_action<karma::simple_center_alignment<Subject, Width> >
: unary_has_semantic_action<Subject> {};
template <typename Subject, typename Padding, typename Width>
struct has_semantic_action<
karma::padding_center_alignment<Subject, Padding, Width> >
: unary_has_semantic_action<Subject> {};
///////////////////////////////////////////////////////////////////////////
template <typename Subject, typename Width, typename Attribute
, typename Context, typename Iterator>
struct handles_container<
karma::simple_center_alignment<Subject, Width>, Attribute
, Context, Iterator>
: unary_handles_container<Subject, Attribute, Context, Iterator> {};
template <typename Subject, typename Padding, typename Width
, typename Attribute, typename Context, typename Iterator>
struct handles_container<
karma::padding_center_alignment<Subject, Padding, Width>
, Attribute, Context, Iterator>
: unary_handles_container<Subject, Attribute, Context, Iterator> {};
}}}
#endif