Create branch to keep WIP patch for modular build.

[SVN r85883]

doc/function_input_iterator.rst

@@ -1,10 +1,13 @@
 :Author:
-    `Dean Michael Berris <mailto:mikhailberis@gmail.com>`_
+    `Dean Michael Berris <mailto:me@deanberris.com>`_
 
 :License:
     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)
 
+:Copyright:
+    Copyright 2012 Google, Inc.
+
 Function Input Iterator
 =======================
 
@@ -15,11 +18,14 @@ the iterator has been incremented. A Function Input Iterator models the
 
 .. _InputIterator: http://www.sgi.com/tech/stl/InputIterator.html
 
-Like the Generator Iterator, the Function Input Iterator takes a function
-that models the Generator_ concept (which is basically a nullary or 0-arity
-function object). Each increment of the function Function Input Iterator
-invokes the generator function and stores the value in the iterator. When
-the iterator is dereferenced the stored value is returned.
+The Function Input Iterator takes a function that models the Generator_ concept
+(which is basically a nullary or 0-arity function object). The first dereference
+of the iterator at a given position invokes the generator function and stores
+and returns the result; subsequent dereferences at the same position simply
+return the same stored result. Incrementing the iterator places it at a new
+position, hence a subsequent dereference will generate a new value via another
+invokation of the generator function. This ensures the generator function is
+invoked precisely when the iterator is requested to return a (new) value.
 
 .. _Generator: http://www.sgi.com/tech/stl/Generator.html
 
@@ -58,7 +64,7 @@ Synopsis
 
         template <class Function, class State>
         typename function_input_iterator<Function, State>
-        make_function_input_iterator(Function & f);
+        make_function_input_iterator(Function & f, State s);
 
         struct infinite;
     }
@@ -112,7 +118,7 @@ it with the ``boost::infinite`` helper class.
     copy(
             make_function_input_iterator(f,infinite()),
             make_function_input_iterator(f,infinite()),
-            ostream_iterator<int>(count, " ")
+            ostream_iterator<int>(cout, " ")
         );
    
 Above, instead of creating a huge vector we rely on the STL copy algorithm

doc/iterator_facade_ref.rst

@@ -106,7 +106,7 @@ The ``iterator_category`` member of ``iterator_facade`` is
 
 .. parsed-literal::
 
-  *iterator-category*\ (CategoryOrTraversal, value_type, reference)
+  *iterator-category*\ (CategoryOrTraversal, reference, value_type)
 
 where *iterator-category* is defined as follows:
 

include/boost/iterator/detail/facade_iterator_category.hpp

@@ -73,15 +73,8 @@ struct iterator_writability_disabled
 // Convert an iterator_facade's traversal category, Value parameter,
 // and ::reference type to an appropriate old-style category.
 //
-// If writability has been disabled per the above metafunction, the
-// result will not be convertible to output_iterator_tag.
-//
-// Otherwise, if Traversal == single_pass_traversal_tag, the following
-// conditions will result in a tag that is convertible both to
-// input_iterator_tag and output_iterator_tag:
-//
-//    1. Reference is a reference to non-const
-//    2. Reference is not a reference and is convertible to Value
+// Due to changeset 21683, this now never results in a category convertible
+// to output_iterator_tag.
 //
 template <class Traversal, class ValueParam, class Reference>
 struct iterator_facade_default_category

include/boost/iterator/detail/operator_brackets_dispatch.hpp

@@ -0,0 +1,88 @@
+// (C) Copyright David Abrahams 2002.
+// (C) Copyright Jeremy Siek    2002.
+// (C) Copyright Thomas Witt    2002.
+// (C) Copyright Jeffrey Lee Hellrung, Jr. 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)
+#ifndef BOOST_OPERATOR_BRACKETS_DISPATCH_07102012JLH_HPP
+#define BOOST_OPERATOR_BRACKETS_DISPATCH_07102012JLH_HPP
+
+#include <boost/iterator/detail/facade_iterator_category.hpp>
+
+#include <boost/type_traits/is_pod.hpp>
+#include <boost/type_traits/remove_const.hpp>
+
+#include <boost/mpl/if.hpp>
+
+namespace boost { namespace detail {
+
+// operator[] must return a proxy in case iterator destruction invalidates
+// referents.
+// To see why, consider the following implementation of operator[]:
+//   reference operator[](difference_type n) const
+//   { return *(*this + n); }
+// The problem here is that operator[] would return a reference created from
+// a temporary iterator.
+
+template <class Value>
+struct operator_brackets_value
+{
+    typedef Value result_type;
+    template <class Iterator>
+    static result_type apply(Iterator const & i)
+    { return *i; }
+};
+
+template <class Iterator, class Reference>
+struct operator_brackets_const_proxy
+{
+    class result_type
+    {
+        Iterator const m_i;
+        explicit result_type(Iterator const & i) : m_i(i) { }
+        friend struct operator_brackets_const_proxy;
+        void operator=(result_type&);
+    public:
+        operator Reference() const { return *m_i; }
+    };
+    static result_type apply(Iterator const & i)
+    { return result_type(i); }
+};
+
+template <class Iterator, class Reference>
+struct operator_brackets_proxy
+{
+    class result_type
+    {
+        Iterator const m_i;
+        explicit result_type(Iterator const & i) : m_i(i) { }
+        friend struct operator_brackets_proxy;
+        void operator=(result_type&);
+    public:
+        operator Reference() const { return *m_i; }
+        operator_brackets_proxy const & operator=(
+          typename Iterator::value_type const & x) const
+        { *m_i = x; return *this; }
+    };
+    static result_type apply(Iterator const & i)
+    { return result_type(i); }
+};
+
+template <class Iterator, class ValueType, class Reference>
+struct operator_brackets_dispatch
+{
+    typedef typename mpl::if_c<
+        iterator_writability_disabled<ValueType,Reference>::value,
+        typename mpl::if_c<
+            boost::is_POD<ValueType>::value,
+            operator_brackets_value<typename boost::remove_const<ValueType>::type>,
+            operator_brackets_const_proxy<Iterator,Reference>
+        >::type,
+        operator_brackets_proxy<Iterator,Reference>
+    >::type type;
+};
+
+} } // namespace detail / namespace boost
+
+#endif // #ifndef BOOST_OPERATOR_BRACKETS_DISPATCH_07102012JLH_HPP

include/boost/iterator/function_input_iterator.hpp

@@ -1,4 +1,6 @@
 // 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)
@@ -7,11 +9,14 @@
 #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 {
 
@@ -29,16 +34,19 @@ namespace boost {
         public:
             function_input_iterator() {}
             function_input_iterator(Function & f_, Input state_ = Input()) 
-                : f(&f_), state(state_), value((*f)()) {}
+                : f(&f_), state(state_) {}
 
             void increment() {
-                value = (*f)();
+                if(value)
+                    value = none;
+                else
+                    (*f)();
                 ++state;
             }
 
             typename Function::result_type const & 
                 dereference() const {
-                    return value;
+                    return (value ? value : value = (*f)()).get();
             }
 
             bool equal(function_input_iterator const & other) const {
@@ -48,7 +56,7 @@ namespace boost {
         private:
             Function * f;
             Input state;
-            typename Function::result_type value;
+            mutable optional<typename Function::result_type> value;
         };
 
         template <class Function, class Input>
@@ -63,17 +71,19 @@ namespace boost {
         public:
             function_pointer_input_iterator() {}
             function_pointer_input_iterator(Function &f_, Input state_ = Input())
-                : f(f_), state(state_), value((*f)()) 
-            {}
+                : f(f_), state(state_) {}
 
             void increment() {
-                value = (*f)();
+                if(value)
+                    value = none;
+                else
+                    (*f)();
                 ++state;
             }
 
             typename function_types::result_type<Function>::type const &
                 dereference() const {
-                    return value;
+                    return (value ? value : value = (*f)()).get();
             }
 
             bool equal(function_pointer_input_iterator const & other) const {
@@ -83,7 +93,7 @@ namespace boost {
         private:
             Function f;
             Input state;
-            typename function_types::result_type<Function>::type value;
+            mutable optional<typename function_types::result_type<Function>::type> value;
         };
 
         template <class Function, class Input>

include/boost/iterator/iterator_facade.hpp

@@ -1,6 +1,7 @@
 // (C) Copyright David Abrahams 2002.
 // (C) Copyright Jeremy Siek    2002.
 // (C) Copyright Thomas Witt    2002.
+// (C) copyright Jeffrey Lee Hellrung, Jr. 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)
@@ -13,6 +14,7 @@
 
 #include <boost/iterator/detail/facade_iterator_category.hpp>
 #include <boost/iterator/detail/enable_if.hpp>
+#include <boost/iterator/detail/operator_brackets_dispatch.hpp>
 
 #include <boost/static_assert.hpp>
 #include <boost/utility/addressof.hpp>
@@ -75,7 +77,7 @@ namespace boost
           , Return
           , int[3]
         >::type type;
-    };        
+    };
 #else
       : ::boost::iterators::enable_if<
            mpl::or_<
@@ -85,7 +87,7 @@ namespace boost
          , Return
         >
     {};
-#endif 
+#endif
 
     //
     // Generates associated types for an iterator_facade with the
@@ -94,7 +96,7 @@ namespace boost
     template <
         class ValueParam
       , class CategoryOrTraversal
-      , class Reference 
+      , class Reference
       , class Difference
     >
     struct iterator_facade_types
@@ -102,16 +104,16 @@ namespace boost
         typedef typename facade_iterator_category<
             CategoryOrTraversal, ValueParam, Reference
         >::type iterator_category;
-        
+
         typedef typename remove_const<ValueParam>::type value_type;
-        
+
         // Not the real associated pointer type
         typedef typename mpl::eval_if<
             boost::detail::iterator_writability_disabled<ValueParam,Reference>
           , add_pointer<const value_type>
           , add_pointer<value_type>
         >::type pointer;
-      
+
 # if defined(BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION)                          \
     && (BOOST_WORKAROUND(_STLPORT_VERSION, BOOST_TESTED_AT(0x452))              \
         || BOOST_WORKAROUND(BOOST_DINKUMWARE_STDLIB, BOOST_TESTED_AT(310)))     \
@@ -147,7 +149,7 @@ namespace boost
 
         // Returning a mutable reference allows nonsense like
         // (*r++).mutate(), but it imposes fewer assumptions about the
-        // behavior of the value_type.  In particular, recall taht
+        // behavior of the value_type.  In particular, recall that
         // (*r).mutate() is legal if operator* returns by value.
         value_type&
         operator*() const
@@ -157,7 +159,7 @@ namespace boost
      private:
         mutable value_type stored_value;
     };
-    
+
     //
     // In general, we can't determine that such an iterator isn't
     // writable -- we also need to store a copy of the old iterator so
@@ -209,7 +211,7 @@ namespace boost
         {
             return stored_iterator;
         }
-        
+
      private:
         mutable value_type stored_value;
         Iterator stored_iterator;
@@ -221,7 +223,7 @@ namespace boost
     struct is_non_proxy_reference_impl
     {
         static Reference r;
-        
+
         template <class R>
         static typename mpl::if_<
             is_convertible<
@@ -231,17 +233,17 @@ namespace boost
           , char[1]
           , char[2]
         >::type& helper(R const&);
-        
+
         BOOST_STATIC_CONSTANT(bool, value = sizeof(helper(r)) == 1);
     };
-        
+
     template <class Reference, class Value>
     struct is_non_proxy_reference
       : mpl::bool_<
             is_non_proxy_reference_impl<Reference, Value>::value
         >
     {};
-# else 
+# else
     template <class Reference, class Value>
     struct is_non_proxy_reference
       : is_convertible<
@@ -250,8 +252,8 @@ namespace boost
           , Value const volatile*
         >
     {};
-# endif 
-        
+# endif
+
     // A metafunction to choose the result type of postfix ++
     //
     // Because the C++98 input iterator requirements say that *r++ has
@@ -273,7 +275,7 @@ namespace boost
             mpl::and_<
                 // A proxy is only needed for readable iterators
                 is_convertible<Reference,Value const&>
-                
+
                 // No multipass iterator can have values that disappear
                 // before positions can be re-visited
               , mpl::not_<
@@ -294,9 +296,9 @@ namespace boost
 
     // operator->() needs special support for input iterators to strictly meet the
     // standard's requirements. If *i is not a reference type, we must still
-    // produce a lvalue to which a pointer can be formed.  We do that by
+    // produce an lvalue to which a pointer can be formed.  We do that by
     // returning a proxy object containing an instance of the reference object.
-    template <class Reference, class Pointer>
+    template <class Reference>
     struct operator_arrow_dispatch // proxy references
     {
         struct proxy
@@ -315,10 +317,10 @@ namespace boost
         }
     };
 
-    template <class T, class Pointer>
-    struct operator_arrow_dispatch<T&, Pointer> // "real" references
+    template <class T>
+    struct operator_arrow_dispatch<T&> // "real" references
     {
-        typedef Pointer result_type;
+        typedef T* result_type;
         static result_type apply(T& x)
         {
             return boost::addressof(x);
@@ -328,79 +330,12 @@ namespace boost
 # if BOOST_WORKAROUND(BOOST_MSVC, < 1300)
     // Deal with ETI
     template<>
-    struct operator_arrow_dispatch<int, int>
+    struct operator_arrow_dispatch<int>
     {
         typedef int result_type;
     };
 # endif
 
-    // A proxy return type for operator[], needed to deal with
-    // iterators that may invalidate referents upon destruction.
-    // Consider the temporary iterator in *(a + n)
-    template <class Iterator>
-    class operator_brackets_proxy
-    {
-        // Iterator is actually an iterator_facade, so we do not have to
-        // go through iterator_traits to access the traits.
-        typedef typename Iterator::reference  reference;
-        typedef typename Iterator::value_type value_type;
-
-     public:
-        operator_brackets_proxy(Iterator const& iter)
-          : m_iter(iter)
-        {}
-
-        operator reference() const
-        {
-            return *m_iter;
-        }
-
-        operator_brackets_proxy& operator=(value_type const& val)
-        {
-            *m_iter = val;
-            return *this;
-        }
-
-     private:
-        Iterator m_iter;
-    };
-
-    // A metafunction that determines whether operator[] must return a
-    // proxy, or whether it can simply return a copy of the value_type.
-    template <class ValueType, class Reference>
-    struct use_operator_brackets_proxy
-      : mpl::not_<
-            mpl::and_<
-                // Really we want an is_copy_constructible trait here,
-                // but is_POD will have to suffice in the meantime.
-                boost::is_POD<ValueType>
-              , iterator_writability_disabled<ValueType,Reference>
-            >
-        >
-    {};
-        
-    template <class Iterator, class Value, class Reference>
-    struct operator_brackets_result
-    {
-        typedef typename mpl::if_<
-            use_operator_brackets_proxy<Value,Reference>
-          , operator_brackets_proxy<Iterator>
-          , Value
-        >::type type;
-    };
-
-    template <class Iterator>
-    operator_brackets_proxy<Iterator> make_operator_brackets_result(Iterator const& iter, mpl::true_)
-    {
-        return operator_brackets_proxy<Iterator>(iter);
-    }
-
-    template <class Iterator>
-    typename Iterator::value_type make_operator_brackets_result(Iterator const& iter, mpl::false_)
-    {
-      return *iter;
-    }
-
     struct choose_difference_type
     {
         template <class I1, class I2>
@@ -414,13 +349,13 @@ namespace boost
             , typename I1::difference_type
             , typename I2::difference_type
           >
-# else 
+# else
           mpl::eval_if<
               is_convertible<I2,I1>
             , iterator_difference<I1>
             , iterator_difference<I2>
           >
-# endif 
+# endif
         {};
 
     };
@@ -438,7 +373,7 @@ namespace boost
     operator op(                                                            \
         iterator_facade<Derived1, V1, TC1, Reference1, Difference1> const& lhs   \
       , iterator_facade<Derived2, V2, TC2, Reference2, Difference2> const& rhs)
-# else 
+# else
 #  define BOOST_ITERATOR_FACADE_INTEROP_HEAD(prefix, op, result_type)   \
     template <                                                          \
         class Derived1, class V1, class TC1, class Reference1, class Difference1 \
@@ -451,7 +386,7 @@ namespace boost
     operator op(                                                        \
         iterator_facade<Derived1, V1, TC1, Reference1, Difference1> const& lhs   \
       , iterator_facade<Derived2, V2, TC2, Reference2, Difference2> const& rhs)
-# endif 
+# endif
 
 #  define BOOST_ITERATOR_FACADE_PLUS_HEAD(prefix,args)              \
     template <class Derived, class V, class TC, class R, class D>   \
@@ -468,12 +403,12 @@ namespace boost
   //
   class iterator_core_access
   {
-# if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)                  
+# if defined(BOOST_NO_MEMBER_TEMPLATE_FRIENDS)
       // Tasteless as this may seem, making all members public allows member templates
       // to work in the absence of member template friends.
    public:
 # else
-      
+
       template <class I, class V, class TC, class R, class D> friend class iterator_facade;
 
 #  define BOOST_ITERATOR_FACADE_RELATION(op)                                \
@@ -616,14 +551,15 @@ namespace boost
       > associated_types;
 
       typedef boost::detail::operator_arrow_dispatch<
-          Reference
-        , typename associated_types::pointer
-      > operator_arrow_dispatch_;
+          Reference> operator_arrow_dispatch_;
+
+      typedef typename boost::detail::operator_brackets_dispatch<
+          Derived, Value, Reference>::type operator_brackets_dispatch_;
 
    protected:
       // For use by derived classes
       typedef iterator_facade<Derived,Value,CategoryOrTraversal,Reference,Difference> iterator_facade_;
-      
+
    public:
 
       typedef typename associated_types::value_type value_type;
@@ -643,16 +579,11 @@ namespace boost
       {
           return operator_arrow_dispatch_::apply(*this->derived());
       }
-        
-      typename boost::detail::operator_brackets_result<Derived,Value,reference>::type
+
+      typename operator_brackets_dispatch_::result_type
       operator[](difference_type n) const
       {
-          typedef boost::detail::use_operator_brackets_proxy<Value,Reference> use_proxy;
-          
-          return boost::detail::make_operator_brackets_result<Derived>(
-              this->derived() + n
-            , use_proxy()
-          );
+          return operator_brackets_dispatch_::apply(this->derived() + n);
       }
 
       Derived& operator++()
@@ -671,7 +602,7 @@ namespace boost
           return tmp;
       }
 # endif
-      
+
       Derived& operator--()
       {
           iterator_core_access::decrement(this->derived());
@@ -726,14 +657,14 @@ namespace boost
   {
       typename boost::detail::postfix_increment_result<I,V,R,TC>::type
           tmp(*static_cast<I*>(&i));
-      
+
       ++i;
-      
+
       return tmp;
   }
-# endif 
+# endif
+
 
-  
   //
   // Comparison operator implementation. The library supplied operators
   // enables the user to provide fully interoperable constant/mutable

include/boost/iterator/reverse_iterator.hpp

@@ -7,8 +7,8 @@
 #ifndef BOOST_REVERSE_ITERATOR_23022003THW_HPP
 #define BOOST_REVERSE_ITERATOR_23022003THW_HPP
 
+#include <boost/next_prior.hpp>
 #include <boost/iterator.hpp>
-#include <boost/utility.hpp>
 #include <boost/iterator/iterator_adaptor.hpp>
 
 namespace boost

test/function_input_iterator_test.cpp

@@ -3,12 +3,17 @@
 // (See accompanying file LICENSE_1_0.txt or copy at
 // http://www.boost.org/LICENSE_1_0.txt)
 
-#include <boost/iterator/function_input_iterator.hpp>
-#include <vector>
-#include <iterator>
 #include <cassert>
+#include <cstddef>
+
 #include <algorithm>
 #include <iostream>
+#include <iterator>
+#include <vector>
+
+#include <boost/iterator/function_input_iterator.hpp>
+
+namespace {
 
 struct ones {
     typedef int result_type;
@@ -21,6 +26,17 @@ int ones_function () {
     return 1;
 }
 
+struct counter {
+    typedef int result_type;
+    int n;
+    explicit counter(int n_) : n(n_) { }
+    result_type operator() () {
+        return n++;
+    }
+};
+
+} // namespace
+
 using namespace std;
 
 int main(int argc, char * argv[])
@@ -65,6 +81,21 @@ int main(int argc, char * argv[])
     assert(equal(values.begin(), values.end(), generated.begin()));
     cout << "function iterator test with reference to function successful." << endl;
 
+    // test the iterator with a stateful function object
+    counter counter_generator(42);
+    vector<int>().swap(generated);
+    copy(
+        boost::make_function_input_iterator(counter_generator, 0),
+        boost::make_function_input_iterator(counter_generator, 10),
+        back_inserter(generated)
+        );
+
+    assert(generated.size() == 10);
+    assert(counter_generator.n == 42 + 10);
+    for(std::size_t i = 0; i != 10; ++i)
+        assert(generated[i] == 42 + i);
+    cout << "function iterator test with stateful function object successful." << endl;
+
     return 0;
 }
 

test/indirect_iter_member_types.cpp

@@ -82,7 +82,7 @@ int main()
     typedef boost::indirect_iterator<char**, int, std::random_access_iterator_tag, long&, short> Iter;
     STATIC_ASSERT_SAME(Iter::value_type, int);
     STATIC_ASSERT_SAME(Iter::reference, long&);  
-    STATIC_ASSERT_SAME(Iter::pointer, int*);  
+    STATIC_ASSERT_SAME(Iter::pointer, long*);  
     STATIC_ASSERT_SAME(Iter::difference_type, short);  
   }
   return 0;