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- /*
- Copyright (c) Marshall Clow 2008-2012.
- 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)
- Revision history:
- 27 June 2009 mtc First version
- 23 Oct 2010 mtc Added predicate version
-
- */
- /// \file clamp.hpp
- /// \brief Clamp algorithm
- /// \author Marshall Clow
- ///
- /// Suggested by olafvdspek in https://svn.boost.org/trac/boost/ticket/3215
- #ifndef BOOST_ALGORITHM_CLAMP_HPP
- #define BOOST_ALGORITHM_CLAMP_HPP
- #include <functional> // For std::less
- #include <iterator> // For std::iterator_traits
- #include <cassert>
- #include <boost/config.hpp>
- #include <boost/range/begin.hpp>
- #include <boost/range/end.hpp>
- #include <boost/mpl/identity.hpp> // for identity
- #include <boost/utility/enable_if.hpp> // for boost::disable_if
- namespace boost { namespace algorithm {
- /// \fn clamp ( T const& val,
- /// typename boost::mpl::identity<T>::type const & lo,
- /// typename boost::mpl::identity<T>::type const & hi, Pred p )
- /// \return the value "val" brought into the range [ lo, hi ]
- /// using the comparison predicate p.
- /// If p ( val, lo ) return lo.
- /// If p ( hi, val ) return hi.
- /// Otherwise, return the original value.
- ///
- /// \param val The value to be clamped
- /// \param lo The lower bound of the range to be clamped to
- /// \param hi The upper bound of the range to be clamped to
- /// \param p A predicate to use to compare the values.
- /// p ( a, b ) returns a boolean.
- ///
- template<typename T, typename Pred>
- BOOST_CXX14_CONSTEXPR T const & clamp ( T const& val,
- typename boost::mpl::identity<T>::type const & lo,
- typename boost::mpl::identity<T>::type const & hi, Pred p )
- {
- // assert ( !p ( hi, lo )); // Can't assert p ( lo, hi ) b/c they might be equal
- return p ( val, lo ) ? lo : p ( hi, val ) ? hi : val;
- }
- /// \fn clamp ( T const& val,
- /// typename boost::mpl::identity<T>::type const & lo,
- /// typename boost::mpl::identity<T>::type const & hi )
- /// \return the value "val" brought into the range [ lo, hi ].
- /// If the value is less than lo, return lo.
- /// If the value is greater than "hi", return hi.
- /// Otherwise, return the original value.
- ///
- /// \param val The value to be clamped
- /// \param lo The lower bound of the range to be clamped to
- /// \param hi The upper bound of the range to be clamped to
- ///
- template<typename T>
- BOOST_CXX14_CONSTEXPR T const& clamp ( const T& val,
- typename boost::mpl::identity<T>::type const & lo,
- typename boost::mpl::identity<T>::type const & hi )
- {
- return boost::algorithm::clamp ( val, lo, hi, std::less<T>());
- }
- /// \fn clamp_range ( InputIterator first, InputIterator last, OutputIterator out,
- /// std::iterator_traits<InputIterator>::value_type const & lo,
- /// std::iterator_traits<InputIterator>::value_type const & hi )
- /// \return clamp the sequence of values [first, last) into [ lo, hi ]
- ///
- /// \param first The start of the range of values
- /// \param last One past the end of the range of input values
- /// \param out An output iterator to write the clamped values into
- /// \param lo The lower bound of the range to be clamped to
- /// \param hi The upper bound of the range to be clamped to
- ///
- template<typename InputIterator, typename OutputIterator>
- BOOST_CXX14_CONSTEXPR OutputIterator clamp_range ( InputIterator first, InputIterator last, OutputIterator out,
- typename std::iterator_traits<InputIterator>::value_type const & lo,
- typename std::iterator_traits<InputIterator>::value_type const & hi )
- {
- // this could also be written with bind and std::transform
- while ( first != last )
- *out++ = boost::algorithm::clamp ( *first++, lo, hi );
- return out;
- }
- /// \fn clamp_range ( const Range &r, OutputIterator out,
- /// typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type const & lo,
- /// typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type const & hi )
- /// \return clamp the sequence of values [first, last) into [ lo, hi ]
- ///
- /// \param r The range of values to be clamped
- /// \param out An output iterator to write the clamped values into
- /// \param lo The lower bound of the range to be clamped to
- /// \param hi The upper bound of the range to be clamped to
- ///
- template<typename Range, typename OutputIterator>
- BOOST_CXX14_CONSTEXPR typename boost::disable_if_c<boost::is_same<Range, OutputIterator>::value, OutputIterator>::type
- clamp_range ( const Range &r, OutputIterator out,
- typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type const & lo,
- typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type const & hi )
- {
- return boost::algorithm::clamp_range ( boost::begin ( r ), boost::end ( r ), out, lo, hi );
- }
- /// \fn clamp_range ( InputIterator first, InputIterator last, OutputIterator out,
- /// std::iterator_traits<InputIterator>::value_type const & lo,
- /// std::iterator_traits<InputIterator>::value_type const & hi, Pred p )
- /// \return clamp the sequence of values [first, last) into [ lo, hi ]
- /// using the comparison predicate p.
- ///
- /// \param first The start of the range of values
- /// \param last One past the end of the range of input values
- /// \param out An output iterator to write the clamped values into
- /// \param lo The lower bound of the range to be clamped to
- /// \param hi The upper bound of the range to be clamped to
- /// \param p A predicate to use to compare the values.
- /// p ( a, b ) returns a boolean.
- ///
- template<typename InputIterator, typename OutputIterator, typename Pred>
- BOOST_CXX14_CONSTEXPR OutputIterator clamp_range ( InputIterator first, InputIterator last, OutputIterator out,
- typename std::iterator_traits<InputIterator>::value_type const & lo,
- typename std::iterator_traits<InputIterator>::value_type const & hi, Pred p )
- {
- // this could also be written with bind and std::transform
- while ( first != last )
- *out++ = boost::algorithm::clamp ( *first++, lo, hi, p );
- return out;
- }
- /// \fn clamp_range ( const Range &r, OutputIterator out,
- /// typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type const & lo,
- /// typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type const & hi,
- /// Pred p )
- /// \return clamp the sequence of values [first, last) into [ lo, hi ]
- /// using the comparison predicate p.
- ///
- /// \param r The range of values to be clamped
- /// \param out An output iterator to write the clamped values into
- /// \param lo The lower bound of the range to be clamped to
- /// \param hi The upper bound of the range to be clamped to
- /// \param p A predicate to use to compare the values.
- /// p ( a, b ) returns a boolean.
- //
- // Disable this template if the first two parameters are the same type;
- // In that case, the user will get the two iterator version.
- template<typename Range, typename OutputIterator, typename Pred>
- BOOST_CXX14_CONSTEXPR typename boost::disable_if_c<boost::is_same<Range, OutputIterator>::value, OutputIterator>::type
- clamp_range ( const Range &r, OutputIterator out,
- typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type const & lo,
- typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type const & hi,
- Pred p )
- {
- return boost::algorithm::clamp_range ( boost::begin ( r ), boost::end ( r ), out, lo, hi, p );
- }
- }}
- #endif // BOOST_ALGORITHM_CLAMP_HPP
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