Pull in some dependencies of Boost.Range.

boost/iterator/function_input_iterator.hpp

@@ -0,0 +1,169 @@
+// Copyright 2009 (C) Dean Michael Berris <me@deanberris.com>
+// Copyright 2012 (C) Google, Inc.
+// Copyright 2012 (C) Jeffrey Lee Hellrung, Jr.
+// 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)
+//
+
+#ifndef BOOST_FUNCTION_INPUT_ITERATOR
+#define BOOST_FUNCTION_INPUT_ITERATOR
+
+#include <boost/assert.hpp>
+#include <boost/mpl/if.hpp>
+#include <boost/function_types/is_function_pointer.hpp>
+#include <boost/function_types/is_function_reference.hpp>
+#include <boost/function_types/result_type.hpp>
+#include <boost/iterator/iterator_facade.hpp>
+#include <boost/none.hpp>
+#include <boost/optional/optional.hpp>
+
+namespace boost {
+
+namespace iterators {
+
+    namespace impl {
+
+        template <class Function, class Input>
+        class function_input_iterator
+            : public iterator_facade<
+            function_input_iterator<Function, Input>,
+            typename Function::result_type,
+            single_pass_traversal_tag,
+            typename Function::result_type const &
+            >
+        {
+        public:
+            function_input_iterator() {}
+            function_input_iterator(Function & f_, Input state_ = Input())
+                : f(&f_), state(state_) {}
+
+            void increment() {
+                if(value)
+                    value = none;
+                else
+                    (*f)();
+                ++state;
+            }
+
+            typename Function::result_type const &
+                dereference() const {
+                    return (value ? value : value = (*f)()).get();
+            }
+
+            bool equal(function_input_iterator const & other) const {
+                return f == other.f && state == other.state;
+            }
+
+        private:
+            Function * f;
+            Input state;
+            mutable optional<typename Function::result_type> value;
+        };
+
+        template <class Function, class Input>
+        class function_pointer_input_iterator
+            : public iterator_facade<
+            function_pointer_input_iterator<Function, Input>,
+            typename function_types::result_type<Function>::type,
+            single_pass_traversal_tag,
+            typename function_types::result_type<Function>::type const &
+            >
+        {
+        public:
+            function_pointer_input_iterator() {}
+            function_pointer_input_iterator(Function &f_, Input state_ = Input())
+                : f(f_), state(state_) {}
+
+            void increment() {
+                if(value)
+                    value = none;
+                else
+                    (*f)();
+                ++state;
+            }
+
+            typename function_types::result_type<Function>::type const &
+                dereference() const {
+                    return (value ? value : value = (*f)()).get();
+            }
+
+            bool equal(function_pointer_input_iterator const & other) const {
+                return f == other.f && state == other.state;
+            }
+
+        private:
+            Function f;
+            Input state;
+            mutable optional<typename function_types::result_type<Function>::type> value;
+        };
+
+        template <class Function, class Input>
+        class function_reference_input_iterator
+            : public function_pointer_input_iterator<Function*,Input>
+        {
+        public:
+            function_reference_input_iterator(Function & f_, Input state_ = Input())
+                : function_pointer_input_iterator<Function*,Input>(&f_, state_)
+            {}
+        };
+
+    } // namespace impl
+
+    template <class Function, class Input>
+    class function_input_iterator
+        : public mpl::if_<
+            function_types::is_function_pointer<Function>,
+            impl::function_pointer_input_iterator<Function,Input>,
+            typename mpl::if_<
+                function_types::is_function_reference<Function>,
+                impl::function_reference_input_iterator<Function,Input>,
+                impl::function_input_iterator<Function,Input>
+            >::type
+        >::type
+    {
+        typedef typename mpl::if_<
+            function_types::is_function_pointer<Function>,
+            impl::function_pointer_input_iterator<Function,Input>,
+            typename mpl::if_<
+                function_types::is_function_reference<Function>,
+                impl::function_reference_input_iterator<Function,Input>,
+                impl::function_input_iterator<Function,Input>
+            >::type
+        >::type base_type;
+    public:
+        function_input_iterator(Function & f, Input i)
+            : base_type(f, i) {}
+    };
+
+    template <class Function, class Input>
+    inline function_input_iterator<Function, Input>
+        make_function_input_iterator(Function & f, Input state) {
+            typedef function_input_iterator<Function, Input> result_t;
+            return result_t(f, state);
+    }
+
+    template <class Function, class Input>
+    inline function_input_iterator<Function*, Input>
+        make_function_input_iterator(Function * f, Input state) {
+            typedef function_input_iterator<Function*, Input> result_t;
+            return result_t(f, state);
+    }
+
+    struct infinite {
+        infinite & operator++() { return *this; }
+        infinite & operator++(int) { return *this; }
+        bool operator==(infinite &) const { return false; };
+        bool operator==(infinite const &) const { return false; };
+    };
+
+} // namespace iterators
+
+using iterators::function_input_iterator;
+using iterators::make_function_input_iterator;
+using iterators::infinite;
+
+} // namespace boost
+
+#endif
+