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| 1 | +/* |
| 2 | + Copyright (c) Marshall Clow 2008-2012. |
| 3 | +
|
| 4 | + Distributed under the Boost Software License, Version 1.0. (See accompanying |
| 5 | + file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) |
| 6 | +
|
| 7 | + Revision history: |
| 8 | + 27 June 2009 mtc First version |
| 9 | + 23 Oct 2010 mtc Added predicate version |
| 10 | + |
| 11 | +*/ |
| 12 | + |
| 13 | +/// \file clamp.hpp |
| 14 | +/// \brief Clamp algorithm |
| 15 | +/// \author Marshall Clow |
| 16 | +/// |
| 17 | +/// Suggested by olafvdspek in https://svn.boost.org/trac/boost/ticket/3215 |
| 18 | + |
| 19 | +#ifndef BOOST_ALGORITHM_CLAMP_HPP |
| 20 | +#define BOOST_ALGORITHM_CLAMP_HPP |
| 21 | + |
| 22 | +#include <functional> // For std::less |
| 23 | +#include <iterator> // For std::iterator_traits |
| 24 | +#include <cassert> |
| 25 | + |
| 26 | +#include <boost/range/begin.hpp> |
| 27 | +#include <boost/range/end.hpp> |
| 28 | +#include <boost/mpl/identity.hpp> // for identity |
| 29 | +#include <boost/utility/enable_if.hpp> // for boost::disable_if |
| 30 | + |
| 31 | +namespace boost { namespace algorithm { |
| 32 | + |
| 33 | +/// \fn clamp ( T const& val, |
| 34 | +/// typename boost::mpl::identity<T>::type const& lo, |
| 35 | +/// typename boost::mpl::identity<T>::type const& hi, Pred p ) |
| 36 | +/// \return the value "val" brought into the range [ lo, hi ] |
| 37 | +/// using the comparison predicate p. |
| 38 | +/// If p ( val, lo ) return lo. |
| 39 | +/// If p ( hi, val ) return hi. |
| 40 | +/// Otherwise, return the original value. |
| 41 | +/// |
| 42 | +/// \param val The value to be clamped |
| 43 | +/// \param lo The lower bound of the range to be clamped to |
| 44 | +/// \param hi The upper bound of the range to be clamped to |
| 45 | +/// \param p A predicate to use to compare the values. |
| 46 | +/// p ( a, b ) returns a boolean. |
| 47 | +/// |
| 48 | + template<typename T, typename Pred> |
| 49 | + T const & clamp ( T const& val, |
| 50 | + typename boost::mpl::identity<T>::type const & lo, |
| 51 | + typename boost::mpl::identity<T>::type const & hi, Pred p ) |
| 52 | + { |
| 53 | +// assert ( !p ( hi, lo )); // Can't assert p ( lo, hi ) b/c they might be equal |
| 54 | + return p ( val, lo ) ? lo : p ( hi, val ) ? hi : val; |
| 55 | + } |
| 56 | + |
| 57 | + |
| 58 | +/// \fn clamp ( T const& val, |
| 59 | +/// typename boost::mpl::identity<T>::type const& lo, |
| 60 | +/// typename boost::mpl::identity<T>::type const& hi ) |
| 61 | +/// \return the value "val" brought into the range [ lo, hi ]. |
| 62 | +/// If the value is less than lo, return lo. |
| 63 | +/// If the value is greater than "hi", return hi. |
| 64 | +/// Otherwise, return the original value. |
| 65 | +/// |
| 66 | +/// \param val The value to be clamped |
| 67 | +/// \param lo The lower bound of the range to be clamped to |
| 68 | +/// \param hi The upper bound of the range to be clamped to |
| 69 | +/// |
| 70 | + template<typename T> |
| 71 | + T const& clamp ( const T& val, |
| 72 | + typename boost::mpl::identity<T>::type const & lo, |
| 73 | + typename boost::mpl::identity<T>::type const & hi ) |
| 74 | + { |
| 75 | + return (clamp) ( val, lo, hi, std::less<T>()); |
| 76 | + } |
| 77 | + |
| 78 | +/// \fn clamp_range ( InputIterator first, InputIterator last, OutputIterator out, |
| 79 | +/// std::iterator_traits<InputIterator>::value_type lo, |
| 80 | +/// std::iterator_traits<InputIterator>::value_type hi ) |
| 81 | +/// \return clamp the sequence of values [first, last) into [ lo, hi ] |
| 82 | +/// |
| 83 | +/// \param first The start of the range of values |
| 84 | +/// \param last One past the end of the range of input values |
| 85 | +/// \param out An output iterator to write the clamped values into |
| 86 | +/// \param lo The lower bound of the range to be clamped to |
| 87 | +/// \param hi The upper bound of the range to be clamped to |
| 88 | +/// |
| 89 | + template<typename InputIterator, typename OutputIterator> |
| 90 | + OutputIterator clamp_range ( InputIterator first, InputIterator last, OutputIterator out, |
| 91 | + typename std::iterator_traits<InputIterator>::value_type lo, |
| 92 | + typename std::iterator_traits<InputIterator>::value_type hi ) |
| 93 | + { |
| 94 | + // this could also be written with bind and std::transform |
| 95 | + while ( first != last ) |
| 96 | + *out++ = clamp ( *first++, lo, hi ); |
| 97 | + return out; |
| 98 | + } |
| 99 | + |
| 100 | +/// \fn clamp_range ( const Range &r, OutputIterator out, |
| 101 | +/// typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type lo, |
| 102 | +/// typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type hi ) |
| 103 | +/// \return clamp the sequence of values [first, last) into [ lo, hi ] |
| 104 | +/// |
| 105 | +/// \param r The range of values to be clamped |
| 106 | +/// \param out An output iterator to write the clamped values into |
| 107 | +/// \param lo The lower bound of the range to be clamped to |
| 108 | +/// \param hi The upper bound of the range to be clamped to |
| 109 | +/// |
| 110 | + template<typename Range, typename OutputIterator> |
| 111 | + typename boost::disable_if_c<boost::is_same<Range, OutputIterator>::value, OutputIterator>::type |
| 112 | + clamp_range ( const Range &r, OutputIterator out, |
| 113 | + typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type lo, |
| 114 | + typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type hi ) |
| 115 | + { |
| 116 | + return clamp_range ( boost::begin ( r ), boost::end ( r ), out, lo, hi ); |
| 117 | + } |
| 118 | + |
| 119 | + |
| 120 | +/// \fn clamp_range ( InputIterator first, InputIterator last, OutputIterator out, |
| 121 | +/// std::iterator_traits<InputIterator>::value_type lo, |
| 122 | +/// std::iterator_traits<InputIterator>::value_type hi, Pred p ) |
| 123 | +/// \return clamp the sequence of values [first, last) into [ lo, hi ] |
| 124 | +/// using the comparison predicate p. |
| 125 | +/// |
| 126 | +/// \param first The start of the range of values |
| 127 | +/// \param last One past the end of the range of input values |
| 128 | +/// \param out An output iterator to write the clamped values into |
| 129 | +/// \param lo The lower bound of the range to be clamped to |
| 130 | +/// \param hi The upper bound of the range to be clamped to |
| 131 | +/// \param p A predicate to use to compare the values. |
| 132 | +/// p ( a, b ) returns a boolean. |
| 133 | + |
| 134 | +/// |
| 135 | + template<typename InputIterator, typename OutputIterator, typename Pred> |
| 136 | + OutputIterator clamp_range ( InputIterator first, InputIterator last, OutputIterator out, |
| 137 | + typename std::iterator_traits<InputIterator>::value_type lo, |
| 138 | + typename std::iterator_traits<InputIterator>::value_type hi, Pred p ) |
| 139 | + { |
| 140 | + // this could also be written with bind and std::transform |
| 141 | + while ( first != last ) |
| 142 | + *out++ = clamp ( *first++, lo, hi, p ); |
| 143 | + return out; |
| 144 | + } |
| 145 | + |
| 146 | +/// \fn clamp_range ( const Range &r, OutputIterator out, |
| 147 | +/// typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type lo, |
| 148 | +/// typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type hi, |
| 149 | +/// Pred p ) |
| 150 | +/// \return clamp the sequence of values [first, last) into [ lo, hi ] |
| 151 | +/// using the comparison predicate p. |
| 152 | +/// |
| 153 | +/// \param r The range of values to be clamped |
| 154 | +/// \param out An output iterator to write the clamped values into |
| 155 | +/// \param lo The lower bound of the range to be clamped to |
| 156 | +/// \param hi The upper bound of the range to be clamped to |
| 157 | +/// \param p A predicate to use to compare the values. |
| 158 | +/// p ( a, b ) returns a boolean. |
| 159 | +// |
| 160 | +// Disable this template if the first two parameters are the same type; |
| 161 | +// In that case, the user will get the two iterator version. |
| 162 | + template<typename Range, typename OutputIterator, typename Pred> |
| 163 | + typename boost::disable_if_c<boost::is_same<Range, OutputIterator>::value, OutputIterator>::type |
| 164 | + clamp_range ( const Range &r, OutputIterator out, |
| 165 | + typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type lo, |
| 166 | + typename std::iterator_traits<typename boost::range_iterator<const Range>::type>::value_type hi, |
| 167 | + Pred p ) |
| 168 | + { |
| 169 | + return clamp_range ( boost::begin ( r ), boost::end ( r ), out, lo, hi, p ); |
| 170 | + } |
| 171 | + |
| 172 | + |
| 173 | +}} |
| 174 | + |
| 175 | +#endif // BOOST_ALGORITHM_CLAMP_HPP |
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