Merge pull request #91 from glenfe/develop

Implement min_element and max_element and sever algorithm dependency

include/boost/range/algorithm/max_element.hpp

@@ -3,17 +3,18 @@
 //  1.0. (See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt)
 //
+// Copyright 2019 Glen Joseph Fernandes (glenjofe@gmail.com)
 //
 // For more information, see http://www.boost.org/libs/range/
 //
 #ifndef BOOST_RANGE_ALGORITHM_MAX_ELEMENT_HPP_INCLUDED
 #define BOOST_RANGE_ALGORITHM_MAX_ELEMENT_HPP_INCLUDED
 
-#include <boost/algorithm/minmax_element.hpp>
 #include <boost/concept_check.hpp>
 #include <boost/range/begin.hpp>
 #include <boost/range/end.hpp>
 #include <boost/range/concepts.hpp>
+#include <boost/range/detail/less.hpp>
 #include <boost/range/detail/range_return.hpp>
 
 namespace boost
@@ -21,6 +22,27 @@ namespace boost
     namespace range
     {
 
+namespace detail
+{
+
+template<typename Iterator, class Predicate>
+inline Iterator
+max_element(Iterator first, Iterator last, Predicate comp)
+{
+    if (first == last) {
+        return last;
+    }
+    Iterator result = first;
+    while (++first != last) {
+        if (comp(*result, *first)) {
+            result = first;
+        }
+    }
+    return result;
+}
+
+} // namespace detail
+
 /// \brief template function max_element
 ///
 /// range-based version of the max_element std algorithm
@@ -32,7 +54,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type
 max_element(ForwardRange& rng)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<ForwardRange> ));
-    return boost::first_max_element(boost::begin(rng), boost::end(rng));
+    return detail::max_element(boost::begin(rng), boost::end(rng), detail::less());
 }
 
 /// \overload
@@ -41,7 +63,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<const ForwardRange>::type
 max_element(const ForwardRange& rng)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<const ForwardRange> ));
-    return boost::first_max_element(boost::begin(rng), boost::end(rng));
+    return detail::max_element(boost::begin(rng), boost::end(rng), detail::less());
 }
 
 /// \overload
@@ -50,7 +72,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type
 max_element(ForwardRange& rng, BinaryPredicate pred)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<ForwardRange> ));
-    return boost::first_max_element(boost::begin(rng), boost::end(rng), pred);
+    return detail::max_element(boost::begin(rng), boost::end(rng), pred);
 }
 
 /// \overload
@@ -59,7 +81,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<const ForwardRange>::type
 max_element(const ForwardRange& rng, BinaryPredicate pred)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<const ForwardRange> ));
-    return boost::first_max_element(boost::begin(rng), boost::end(rng), pred);
+    return detail::max_element(boost::begin(rng), boost::end(rng), pred);
 }
 
 // range_return overloads
@@ -71,7 +93,7 @@ max_element(ForwardRange& rng)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<ForwardRange> ));
     return range_return<ForwardRange,re>::pack(
-        boost::first_max_element(boost::begin(rng), boost::end(rng)),
+        detail::max_element(boost::begin(rng), boost::end(rng), detail::less()),
         rng);
 }
 
@@ -82,7 +104,7 @@ max_element(const ForwardRange& rng)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<const ForwardRange> ));
     return range_return<const ForwardRange,re>::pack(
-        boost::first_max_element(boost::begin(rng), boost::end(rng)),
+        detail::max_element(boost::begin(rng), boost::end(rng), detail::less()),
         rng);
 }
 
@@ -93,7 +115,7 @@ max_element(ForwardRange& rng, BinaryPredicate pred)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<ForwardRange> ));
     return range_return<ForwardRange,re>::pack(
-        boost::first_max_element(boost::begin(rng), boost::end(rng), pred),
+        detail::max_element(boost::begin(rng), boost::end(rng), pred),
         rng);
 }
 
@@ -104,7 +126,7 @@ max_element(const ForwardRange& rng, BinaryPredicate pred)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<const ForwardRange> ));
     return range_return<const ForwardRange,re>::pack(
-        boost::first_max_element(boost::begin(rng), boost::end(rng), pred),
+        detail::max_element(boost::begin(rng), boost::end(rng), pred),
         rng);
 }
 

include/boost/range/algorithm/min_element.hpp

@@ -3,17 +3,18 @@
 //  1.0. (See accompanying file LICENSE_1_0.txt or copy at
 //  http://www.boost.org/LICENSE_1_0.txt)
 //
+// Copyright 2019 Glen Joseph Fernandes (glenjofe@gmail.com)
 //
 // For more information, see http://www.boost.org/libs/range/
 //
 #ifndef BOOST_RANGE_ALGORITHM_MIN_ELEMENT_HPP_INCLUDED
 #define BOOST_RANGE_ALGORITHM_MIN_ELEMENT_HPP_INCLUDED
 
-#include <boost/algorithm/minmax_element.hpp>
 #include <boost/concept_check.hpp>
 #include <boost/range/begin.hpp>
 #include <boost/range/end.hpp>
 #include <boost/range/concepts.hpp>
+#include <boost/range/detail/less.hpp>
 #include <boost/range/detail/range_return.hpp>
 
 namespace boost
@@ -21,6 +22,27 @@ namespace boost
     namespace range
     {
 
+namespace detail
+{
+
+template<typename Iterator, class Predicate>
+inline Iterator
+min_element(Iterator first, Iterator last, Predicate comp)
+{
+    if (first == last) {
+        return last;
+    }
+    Iterator result = first;
+    while (++first != last) {
+        if (comp(*first, *result)) {
+            result = first;
+        }
+    }
+    return result;
+}
+
+} // namespace detail
+
 /// \brief template function min_element
 ///
 /// range-based version of the min_element std algorithm
@@ -32,7 +54,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type
 min_element(ForwardRange& rng)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<ForwardRange> ));
-    return boost::first_min_element(boost::begin(rng), boost::end(rng));
+    return detail::min_element(boost::begin(rng), boost::end(rng), detail::less());
 }
 
 /// \overload
@@ -41,7 +63,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<const ForwardRange>::type
 min_element(const ForwardRange& rng)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<const ForwardRange> ));
-    return boost::first_min_element(boost::begin(rng), boost::end(rng));
+    return detail::min_element(boost::begin(rng), boost::end(rng), detail::less());
 }
 
 /// \overload
@@ -50,7 +72,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<ForwardRange>::type
 min_element(ForwardRange& rng, BinaryPredicate pred)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<ForwardRange> ));
-    return boost::first_min_element(boost::begin(rng), boost::end(rng), pred);
+    return detail::min_element(boost::begin(rng), boost::end(rng), pred);
 }
 
 /// \overload
@@ -59,7 +81,7 @@ inline BOOST_DEDUCED_TYPENAME range_iterator<const ForwardRange>::type
 min_element(const ForwardRange& rng, BinaryPredicate pred)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<const ForwardRange> ));
-    return boost::first_min_element(boost::begin(rng), boost::end(rng), pred);
+    return detail::min_element(boost::begin(rng), boost::end(rng), pred);
 }
 
 // range_return overloads
@@ -71,7 +93,7 @@ min_element(ForwardRange& rng)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<ForwardRange> ));
     return range_return<ForwardRange,re>::pack(
-        boost::first_min_element(boost::begin(rng), boost::end(rng)),
+        detail::min_element(boost::begin(rng), boost::end(rng), detail::less()),
         rng);
 }
 
@@ -82,7 +104,7 @@ min_element(const ForwardRange& rng)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<const ForwardRange> ));
     return range_return<const ForwardRange,re>::pack(
-        boost::first_min_element(boost::begin(rng), boost::end(rng)),
+        detail::min_element(boost::begin(rng), boost::end(rng), detail::less()),
         rng);
 }
 
@@ -93,7 +115,7 @@ min_element(ForwardRange& rng, BinaryPredicate pred)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<ForwardRange> ));
     return range_return<ForwardRange,re>::pack(
-        boost::first_min_element(boost::begin(rng), boost::end(rng), pred),
+        detail::min_element(boost::begin(rng), boost::end(rng), pred),
         rng);
 }
 
@@ -104,7 +126,7 @@ min_element(const ForwardRange& rng, BinaryPredicate pred)
 {
     BOOST_RANGE_CONCEPT_ASSERT(( ForwardRangeConcept<const ForwardRange> ));
     return range_return<const ForwardRange,re>::pack(
-        boost::first_min_element(boost::begin(rng), boost::end(rng), pred),
+        detail::min_element(boost::begin(rng), boost::end(rng), pred),
         rng);
 }
 

include/boost/range/detail/less.hpp

@@ -0,0 +1,26 @@
+/*
+Copyright 2019 Glen Joseph Fernandes
+(glenjofe@gmail.com)
+
+Distributed under the Boost Software License, Version 1.0.
+(http://www.boost.org/LICENSE_1_0.txt)
+*/
+#ifndef BOOST_RANGE_DETAIL_LESS
+#define BOOST_RANGE_DETAIL_LESS
+
+namespace boost {
+namespace range {
+namespace detail {
+
+struct less {
+    template<class T, class U>
+    bool operator()(const T& lhs, const U& rhs) const {
+        return lhs < rhs;
+    }
+};
+
+} /* detail */
+} /* range */
+} /* boost */
+
+#endif