// Boost.Range library concept checks | |
// | |
// Copyright Neil Groves 2009. Use, modification and distribution | |
// are subject to 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) | |
// | |
// Copyright Daniel Walker 2006. Use, modification and distribution | |
// are subject to 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/libs/range/ | |
// | |
#ifndef BOOST_RANGE_CONCEPTS_HPP | |
#define BOOST_RANGE_CONCEPTS_HPP | |
#include <boost/concept_check.hpp> | |
#include <boost/iterator/iterator_concepts.hpp> | |
#include <boost/range/begin.hpp> | |
#include <boost/range/end.hpp> | |
#include <boost/range/iterator.hpp> | |
#include <boost/range/value_type.hpp> | |
#include <boost/range/detail/misc_concept.hpp> | |
/*! | |
* \file | |
* \brief Concept checks for the Boost Range library. | |
* | |
* The structures in this file may be used in conjunction with the | |
* Boost Concept Check library to insure that the type of a function | |
* parameter is compatible with a range concept. If not, a meaningful | |
* compile time error is generated. Checks are provided for the range | |
* concepts related to iterator traversal categories. For example, the | |
* following line checks that the type T models the ForwardRange | |
* concept. | |
* | |
* \code | |
* BOOST_CONCEPT_ASSERT((ForwardRangeConcept<T>)); | |
* \endcode | |
* | |
* A different concept check is required to ensure writeable value | |
* access. For example to check for a ForwardRange that can be written | |
* to, the following code is required. | |
* | |
* \code | |
* BOOST_CONCEPT_ASSERT((WriteableForwardRangeConcept<T>)); | |
* \endcode | |
* | |
* \see http://www.boost.org/libs/range/doc/range.html for details | |
* about range concepts. | |
* \see http://www.boost.org/libs/iterator/doc/iterator_concepts.html | |
* for details about iterator concepts. | |
* \see http://www.boost.org/libs/concept_check/concept_check.htm for | |
* details about concept checks. | |
*/ | |
namespace boost { | |
namespace range_detail { | |
#ifndef BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
// List broken compiler versions here: | |
#ifdef __GNUC__ | |
// GNUC 4.2 has strange issues correctly detecting compliance with the Concepts | |
// hence the least disruptive approach is to turn-off the concept checking for | |
// this version of the compiler. | |
#if __GNUC__ == 4 && __GNUC_MINOR__ == 2 | |
#define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 | |
#endif | |
#endif | |
#ifdef __BORLANDC__ | |
#define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 | |
#endif | |
#ifdef __PATHCC__ | |
#define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 0 | |
#endif | |
// Default to using the concept asserts unless we have defined it off | |
// during the search for black listed compilers. | |
#ifndef BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
#define BOOST_RANGE_ENABLE_CONCEPT_ASSERT 1 | |
#endif | |
#endif | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
#define BOOST_RANGE_CONCEPT_ASSERT( x ) BOOST_CONCEPT_ASSERT( x ) | |
#else | |
#define BOOST_RANGE_CONCEPT_ASSERT( x ) | |
#endif | |
// Rationale for the inclusion of redefined iterator concept | |
// classes: | |
// | |
// The Range algorithms often do not require that the iterators are | |
// Assignable or default constructable, but the correct standard | |
// conformant iterators do require the iterators to be a model of the | |
// Assignable concept. | |
// Iterators that contains a functor that is not assignable therefore | |
// are not correct models of the standard iterator concepts, | |
// despite being adequate for most algorithms. An example of this | |
// use case is the combination of the boost::adaptors::filtered | |
// class with a boost::lambda::bind generated functor. | |
// Ultimately modeling the range concepts using composition | |
// with the Boost.Iterator concepts would render the library | |
// incompatible with many common Boost.Lambda expressions. | |
template<class Iterator> | |
struct IncrementableIteratorConcept : CopyConstructible<Iterator> | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
typedef BOOST_DEDUCED_TYPENAME iterator_traversal<Iterator>::type traversal_category; | |
BOOST_RANGE_CONCEPT_ASSERT(( | |
Convertible< | |
traversal_category, | |
incrementable_traversal_tag | |
>)); | |
BOOST_CONCEPT_USAGE(IncrementableIteratorConcept) | |
{ | |
++i; | |
(void)i++; | |
} | |
private: | |
Iterator i; | |
#endif | |
}; | |
template<class Iterator> | |
struct SinglePassIteratorConcept | |
: IncrementableIteratorConcept<Iterator> | |
, EqualityComparable<Iterator> | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
BOOST_RANGE_CONCEPT_ASSERT(( | |
Convertible< | |
BOOST_DEDUCED_TYPENAME SinglePassIteratorConcept::traversal_category, | |
single_pass_traversal_tag | |
>)); | |
BOOST_CONCEPT_USAGE(SinglePassIteratorConcept) | |
{ | |
Iterator i2(++i); | |
boost::ignore_unused_variable_warning(i2); | |
// deliberately we are loose with the postfix version for the single pass | |
// iterator due to the commonly poor adherence to the specification means that | |
// many algorithms would be unusable, whereas actually without the check they | |
// work | |
(void)(i++); | |
BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r1(*i); | |
boost::ignore_unused_variable_warning(r1); | |
BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r2(*(++i)); | |
boost::ignore_unused_variable_warning(r2); | |
} | |
private: | |
Iterator i; | |
#endif | |
}; | |
template<class Iterator> | |
struct ForwardIteratorConcept | |
: SinglePassIteratorConcept<Iterator> | |
, DefaultConstructible<Iterator> | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
typedef BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::difference_type difference_type; | |
BOOST_MPL_ASSERT((is_integral<difference_type>)); | |
BOOST_MPL_ASSERT_RELATION(std::numeric_limits<difference_type>::is_signed, ==, true); | |
BOOST_RANGE_CONCEPT_ASSERT(( | |
Convertible< | |
BOOST_DEDUCED_TYPENAME ForwardIteratorConcept::traversal_category, | |
forward_traversal_tag | |
>)); | |
BOOST_CONCEPT_USAGE(ForwardIteratorConcept) | |
{ | |
// See the above note in the SinglePassIteratorConcept about the handling of the | |
// postfix increment. Since with forward and better iterators there is no need | |
// for a proxy, we can sensibly require that the dereference result | |
// is convertible to reference. | |
Iterator i2(i++); | |
boost::ignore_unused_variable_warning(i2); | |
BOOST_DEDUCED_TYPENAME boost::detail::iterator_traits<Iterator>::reference r(*(i++)); | |
boost::ignore_unused_variable_warning(r); | |
} | |
private: | |
Iterator i; | |
#endif | |
}; | |
template<class Iterator> | |
struct BidirectionalIteratorConcept | |
: ForwardIteratorConcept<Iterator> | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
BOOST_RANGE_CONCEPT_ASSERT(( | |
Convertible< | |
BOOST_DEDUCED_TYPENAME BidirectionalIteratorConcept::traversal_category, | |
bidirectional_traversal_tag | |
>)); | |
BOOST_CONCEPT_USAGE(BidirectionalIteratorConcept) | |
{ | |
--i; | |
(void)i--; | |
} | |
private: | |
Iterator i; | |
#endif | |
}; | |
template<class Iterator> | |
struct RandomAccessIteratorConcept | |
: BidirectionalIteratorConcept<Iterator> | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
BOOST_RANGE_CONCEPT_ASSERT(( | |
Convertible< | |
BOOST_DEDUCED_TYPENAME RandomAccessIteratorConcept::traversal_category, | |
random_access_traversal_tag | |
>)); | |
BOOST_CONCEPT_USAGE(RandomAccessIteratorConcept) | |
{ | |
i += n; | |
i = i + n; | |
i = n + i; | |
i -= n; | |
i = i - n; | |
n = i - j; | |
} | |
private: | |
BOOST_DEDUCED_TYPENAME RandomAccessIteratorConcept::difference_type n; | |
Iterator i; | |
Iterator j; | |
#endif | |
}; | |
} // namespace range_detail | |
//! Check if a type T models the SinglePassRange range concept. | |
template<class T> | |
struct SinglePassRangeConcept | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
typedef BOOST_DEDUCED_TYPENAME range_iterator<T const>::type const_iterator; | |
typedef BOOST_DEDUCED_TYPENAME range_iterator<T>::type iterator; | |
BOOST_RANGE_CONCEPT_ASSERT((range_detail::SinglePassIteratorConcept<iterator>)); | |
BOOST_RANGE_CONCEPT_ASSERT((range_detail::SinglePassIteratorConcept<const_iterator>)); | |
BOOST_CONCEPT_USAGE(SinglePassRangeConcept) | |
{ | |
// This has been modified from assigning to this->i | |
// (where i was a member variable) to improve | |
// compatibility with Boost.Lambda | |
iterator i1 = boost::begin(*m_range); | |
iterator i2 = boost::end(*m_range); | |
ignore_unused_variable_warning(i1); | |
ignore_unused_variable_warning(i2); | |
const_constraints(*m_range); | |
} | |
private: | |
void const_constraints(const T& const_range) | |
{ | |
const_iterator ci1 = boost::begin(const_range); | |
const_iterator ci2 = boost::end(const_range); | |
ignore_unused_variable_warning(ci1); | |
ignore_unused_variable_warning(ci2); | |
} | |
// Rationale: | |
// The type of m_range is T* rather than T because it allows | |
// T to be an abstract class. The other obvious alternative of | |
// T& produces a warning on some compilers. | |
T* m_range; | |
#endif | |
}; | |
//! Check if a type T models the ForwardRange range concept. | |
template<class T> | |
struct ForwardRangeConcept : SinglePassRangeConcept<T> | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
BOOST_RANGE_CONCEPT_ASSERT((range_detail::ForwardIteratorConcept<BOOST_DEDUCED_TYPENAME ForwardRangeConcept::iterator>)); | |
BOOST_RANGE_CONCEPT_ASSERT((range_detail::ForwardIteratorConcept<BOOST_DEDUCED_TYPENAME ForwardRangeConcept::const_iterator>)); | |
#endif | |
}; | |
template<class Range> | |
struct WriteableRangeConcept | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
typedef BOOST_DEDUCED_TYPENAME range_iterator<Range>::type iterator; | |
BOOST_CONCEPT_USAGE(WriteableRangeConcept) | |
{ | |
*i = v; | |
} | |
private: | |
iterator i; | |
BOOST_DEDUCED_TYPENAME range_value<Range>::type v; | |
#endif | |
}; | |
//! Check if a type T models the WriteableForwardRange range concept. | |
template<class T> | |
struct WriteableForwardRangeConcept | |
: ForwardRangeConcept<T> | |
, WriteableRangeConcept<T> | |
{ | |
}; | |
//! Check if a type T models the BidirectionalRange range concept. | |
template<class T> | |
struct BidirectionalRangeConcept : ForwardRangeConcept<T> | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
BOOST_RANGE_CONCEPT_ASSERT((BidirectionalIteratorConcept<BOOST_DEDUCED_TYPENAME BidirectionalRangeConcept::iterator>)); | |
BOOST_RANGE_CONCEPT_ASSERT((BidirectionalIteratorConcept<BOOST_DEDUCED_TYPENAME BidirectionalRangeConcept::const_iterator>)); | |
#endif | |
}; | |
//! Check if a type T models the WriteableBidirectionalRange range concept. | |
template<class T> | |
struct WriteableBidirectionalRangeConcept | |
: BidirectionalRangeConcept<T> | |
, WriteableRangeConcept<T> | |
{ | |
}; | |
//! Check if a type T models the RandomAccessRange range concept. | |
template<class T> | |
struct RandomAccessRangeConcept : BidirectionalRangeConcept<T> | |
{ | |
#if BOOST_RANGE_ENABLE_CONCEPT_ASSERT | |
BOOST_RANGE_CONCEPT_ASSERT((RandomAccessIteratorConcept<BOOST_DEDUCED_TYPENAME RandomAccessRangeConcept::iterator>)); | |
BOOST_RANGE_CONCEPT_ASSERT((RandomAccessIteratorConcept<BOOST_DEDUCED_TYPENAME RandomAccessRangeConcept::const_iterator>)); | |
#endif | |
}; | |
//! Check if a type T models the WriteableRandomAccessRange range concept. | |
template<class T> | |
struct WriteableRandomAccessRangeConcept | |
: RandomAccessRangeConcept<T> | |
, WriteableRangeConcept<T> | |
{ | |
}; | |
} // namespace boost | |
#endif // BOOST_RANGE_CONCEPTS_HPP |