Chris@16: // Copyright 2009 (C) Dean Michael Berris <me@deanberris.com>
Chris@16: // Copyright 2012 (C) Google, Inc.
Chris@16: // Copyright 2012 (C) Jeffrey Lee Hellrung, Jr.
Chris@16: // Distributed under the Boost Software License, Version 1.0. (See
Chris@16: // accompanying file LICENSE_1_0.txt or copy at
Chris@16: // http://www.boost.org/LICENSE_1_0.txt)
Chris@16: //
Chris@16: 
Chris@16: #ifndef BOOST_FUNCTION_INPUT_ITERATOR
Chris@16: #define BOOST_FUNCTION_INPUT_ITERATOR
Chris@16: 
Chris@16: #include <boost/assert.hpp>
Chris@16: #include <boost/mpl/if.hpp>
Chris@16: #include <boost/function_types/is_function_pointer.hpp>
Chris@16: #include <boost/function_types/is_function_reference.hpp>
Chris@16: #include <boost/function_types/result_type.hpp>
Chris@16: #include <boost/iterator/iterator_facade.hpp>
Chris@16: #include <boost/none.hpp>
Chris@16: #include <boost/optional/optional.hpp>
Chris@16: 
Chris@16: namespace boost {
Chris@16: 
Chris@101: namespace iterators {
Chris@101: 
Chris@16:     namespace impl {
Chris@16: 
Chris@16:         template <class Function, class Input>
Chris@16:         class function_input_iterator
Chris@16:             : public iterator_facade<
Chris@16:             function_input_iterator<Function, Input>,
Chris@16:             typename Function::result_type,
Chris@16:             single_pass_traversal_tag,
Chris@16:             typename Function::result_type const &
Chris@16:             >
Chris@16:         {
Chris@16:         public:
Chris@16:             function_input_iterator() {}
Chris@101:             function_input_iterator(Function & f_, Input state_ = Input())
Chris@16:                 : f(&f_), state(state_) {}
Chris@16: 
Chris@16:             void increment() {
Chris@16:                 if(value)
Chris@16:                     value = none;
Chris@16:                 else
Chris@16:                     (*f)();
Chris@16:                 ++state;
Chris@16:             }
Chris@16: 
Chris@101:             typename Function::result_type const &
Chris@16:                 dereference() const {
Chris@16:                     return (value ? value : value = (*f)()).get();
Chris@16:             }
Chris@16: 
Chris@16:             bool equal(function_input_iterator const & other) const {
Chris@16:                 return f == other.f && state == other.state;
Chris@16:             }
Chris@16: 
Chris@16:         private:
Chris@16:             Function * f;
Chris@16:             Input state;
Chris@16:             mutable optional<typename Function::result_type> value;
Chris@16:         };
Chris@16: 
Chris@16:         template <class Function, class Input>
Chris@16:         class function_pointer_input_iterator
Chris@16:             : public iterator_facade<
Chris@16:             function_pointer_input_iterator<Function, Input>,
Chris@16:             typename function_types::result_type<Function>::type,
Chris@16:             single_pass_traversal_tag,
Chris@16:             typename function_types::result_type<Function>::type const &
Chris@16:             >
Chris@16:         {
Chris@16:         public:
Chris@16:             function_pointer_input_iterator() {}
Chris@16:             function_pointer_input_iterator(Function &f_, Input state_ = Input())
Chris@16:                 : f(f_), state(state_) {}
Chris@16: 
Chris@16:             void increment() {
Chris@16:                 if(value)
Chris@16:                     value = none;
Chris@16:                 else
Chris@16:                     (*f)();
Chris@16:                 ++state;
Chris@16:             }
Chris@16: 
Chris@16:             typename function_types::result_type<Function>::type const &
Chris@16:                 dereference() const {
Chris@16:                     return (value ? value : value = (*f)()).get();
Chris@16:             }
Chris@16: 
Chris@16:             bool equal(function_pointer_input_iterator const & other) const {
Chris@16:                 return f == other.f && state == other.state;
Chris@16:             }
Chris@16: 
Chris@16:         private:
Chris@16:             Function f;
Chris@16:             Input state;
Chris@16:             mutable optional<typename function_types::result_type<Function>::type> value;
Chris@16:         };
Chris@16: 
Chris@16:         template <class Function, class Input>
Chris@16:         class function_reference_input_iterator
Chris@16:             : public function_pointer_input_iterator<Function*,Input>
Chris@16:         {
Chris@16:         public:
Chris@16:             function_reference_input_iterator(Function & f_, Input state_ = Input())
Chris@16:                 : function_pointer_input_iterator<Function*,Input>(&f_, state_)
Chris@16:             {}
Chris@16:         };
Chris@16: 
Chris@16:     } // namespace impl
Chris@16: 
Chris@16:     template <class Function, class Input>
Chris@101:     class function_input_iterator
Chris@16:         : public mpl::if_<
Chris@16:             function_types::is_function_pointer<Function>,
Chris@16:             impl::function_pointer_input_iterator<Function,Input>,
Chris@16:             typename mpl::if_<
Chris@16:                 function_types::is_function_reference<Function>,
Chris@16:                 impl::function_reference_input_iterator<Function,Input>,
Chris@16:                 impl::function_input_iterator<Function,Input>
Chris@16:             >::type
Chris@16:         >::type
Chris@16:     {
Chris@16:         typedef typename mpl::if_<
Chris@16:             function_types::is_function_pointer<Function>,
Chris@16:             impl::function_pointer_input_iterator<Function,Input>,
Chris@16:             typename mpl::if_<
Chris@16:                 function_types::is_function_reference<Function>,
Chris@16:                 impl::function_reference_input_iterator<Function,Input>,
Chris@16:                 impl::function_input_iterator<Function,Input>
Chris@16:             >::type
Chris@16:         >::type base_type;
Chris@16:     public:
Chris@16:         function_input_iterator(Function & f, Input i)
Chris@16:             : base_type(f, i) {}
Chris@16:     };
Chris@16: 
Chris@16:     template <class Function, class Input>
Chris@16:     inline function_input_iterator<Function, Input>
Chris@16:         make_function_input_iterator(Function & f, Input state) {
Chris@16:             typedef function_input_iterator<Function, Input> result_t;
Chris@16:             return result_t(f, state);
Chris@16:     }
Chris@16: 
Chris@16:     template <class Function, class Input>
Chris@16:     inline function_input_iterator<Function*, Input>
Chris@16:         make_function_input_iterator(Function * f, Input state) {
Chris@16:             typedef function_input_iterator<Function*, Input> result_t;
Chris@16:             return result_t(f, state);
Chris@16:     }
Chris@16: 
Chris@16:     struct infinite {
Chris@16:         infinite & operator++() { return *this; }
Chris@16:         infinite & operator++(int) { return *this; }
Chris@16:         bool operator==(infinite &) const { return false; };
Chris@16:         bool operator==(infinite const &) const { return false; };
Chris@16:     };
Chris@101: 
Chris@101: } // namespace iterators
Chris@101: 
Chris@101: using iterators::function_input_iterator;
Chris@101: using iterators::make_function_input_iterator;
Chris@101: using iterators::infinite;
Chris@101: 
Chris@101: } // namespace boost
Chris@16: 
Chris@16: #endif
Chris@16: