williamr@2: //  Boost operators.hpp header file  ----------------------------------------//
williamr@2: 
williamr@2: //  (C) Copyright David Abrahams, Jeremy Siek, Daryle Walker 1999-2001.
williamr@2: //  Distributed under the Boost Software License, Version 1.0. (See
williamr@2: //  accompanying file LICENSE_1_0.txt or copy at
williamr@2: //  http://www.boost.org/LICENSE_1_0.txt)
williamr@2: 
williamr@2: //  See http://www.boost.org/libs/utility/operators.htm for documentation.
williamr@2: 
williamr@2: //  Revision History
williamr@2: //  21 Oct 02 Modified implementation of operators to allow compilers with a
williamr@2: //            correct named return value optimization (NRVO) to produce optimal
williamr@2: //            code.  (Daniel Frey)
williamr@2: //  02 Dec 01 Bug fixed in random_access_iteratable.  (Helmut Zeisel)
williamr@2: //  28 Sep 01 Factored out iterator operator groups.  (Daryle Walker)
williamr@2: //  27 Aug 01 'left' form for non commutative operators added;
williamr@2: //            additional classes for groups of related operators added;
williamr@2: //            workaround for empty base class optimization
williamr@2: //            bug of GCC 3.0 (Helmut Zeisel)
williamr@2: //  25 Jun 01 output_iterator_helper changes: removed default template 
williamr@2: //            parameters, added support for self-proxying, additional 
williamr@2: //            documentation and tests (Aleksey Gurtovoy)
williamr@2: //  29 May 01 Added operator classes for << and >>.  Added input and output
williamr@2: //            iterator helper classes.  Added classes to connect equality and
williamr@2: //            relational operators.  Added classes for groups of related
williamr@2: //            operators.  Reimplemented example operator and iterator helper
williamr@2: //            classes in terms of the new groups.  (Daryle Walker, with help
williamr@2: //            from Alexy Gurtovoy)
williamr@2: //  11 Feb 01 Fixed bugs in the iterator helpers which prevented explicitly
williamr@2: //            supplied arguments from actually being used (Dave Abrahams)
williamr@2: //  04 Jul 00 Fixed NO_OPERATORS_IN_NAMESPACE bugs, major cleanup and
williamr@2: //            refactoring of compiler workarounds, additional documentation
williamr@2: //            (Alexy Gurtovoy and Mark Rodgers with some help and prompting from
williamr@2: //            Dave Abrahams) 
williamr@2: //  28 Jun 00 General cleanup and integration of bugfixes from Mark Rodgers and
williamr@2: //            Jeremy Siek (Dave Abrahams)
williamr@2: //  20 Jun 00 Changes to accommodate Borland C++Builder 4 and Borland C++ 5.5
williamr@2: //            (Mark Rodgers)
williamr@2: //  20 Jun 00 Minor fixes to the prior revision (Aleksey Gurtovoy)
williamr@2: //  10 Jun 00 Support for the base class chaining technique was added
williamr@2: //            (Aleksey Gurtovoy). See documentation and the comments below 
williamr@2: //            for the details. 
williamr@2: //  12 Dec 99 Initial version with iterator operators (Jeremy Siek)
williamr@2: //  18 Nov 99 Change name "divideable" to "dividable", remove unnecessary
williamr@2: //            specializations of dividable, subtractable, modable (Ed Brey) 
williamr@2: //  17 Nov 99 Add comments (Beman Dawes)
williamr@2: //            Remove unnecessary specialization of operators<> (Ed Brey)
williamr@2: //  15 Nov 99 Fix less_than_comparable<T,U> second operand type for first two
williamr@2: //            operators.(Beman Dawes)
williamr@2: //  12 Nov 99 Add operators templates (Ed Brey)
williamr@2: //  11 Nov 99 Add single template parameter version for compilers without
williamr@2: //            partial specialization (Beman Dawes)
williamr@2: //  10 Nov 99 Initial version
williamr@2: 
williamr@2: // 10 Jun 00:
williamr@2: // An additional optional template parameter was added to most of 
williamr@2: // operator templates to support the base class chaining technique (see 
williamr@2: // documentation for the details). Unfortunately, a straightforward
williamr@2: // implementation of this change would have broken compatibility with the
williamr@2: // previous version of the library by making it impossible to use the same
williamr@2: // template name (e.g. 'addable') for both the 1- and 2-argument versions of
williamr@2: // an operator template. This implementation solves the backward-compatibility
williamr@2: // issue at the cost of some simplicity.
williamr@2: //
williamr@2: // One of the complications is an existence of special auxiliary class template
williamr@2: // 'is_chained_base<>' (see 'detail' namespace below), which is used
williamr@2: // to determine whether its template parameter is a library's operator template
williamr@2: // or not. You have to specialize 'is_chained_base<>' for each new 
williamr@2: // operator template you add to the library.
williamr@2: //
williamr@2: // However, most of the non-trivial implementation details are hidden behind 
williamr@2: // several local macros defined below, and as soon as you understand them,
williamr@2: // you understand the whole library implementation. 
williamr@2: 
williamr@2: #ifndef BOOST_OPERATORS_HPP
williamr@2: #define BOOST_OPERATORS_HPP
williamr@2: 
williamr@2: #include <boost/config.hpp>
williamr@2: #include <boost/iterator.hpp>
williamr@2: #include <boost/detail/workaround.hpp>
williamr@2: 
williamr@2: #if defined(__sgi) && !defined(__GNUC__)
williamr@2: #   pragma set woff 1234
williamr@2: #endif
williamr@2: 
williamr@2: #if defined(BOOST_MSVC)
williamr@2: #   pragma warning( disable : 4284 ) // complaint about return type of 
williamr@2: #endif                               // operator-> not begin a UDT
williamr@2: 
williamr@2: namespace boost {
williamr@2: namespace detail {
williamr@2: 
williamr@2: // Helmut Zeisel, empty base class optimization bug with GCC 3.0.0
williamr@2: #if defined(__GNUC__) && __GNUC__==3 && __GNUC_MINOR__==0 && __GNU_PATCHLEVEL__==0
williamr@2: class empty_base {
williamr@2:   bool dummy; 
williamr@2: };
williamr@2: #else
williamr@2: class empty_base {};
williamr@2: #endif
williamr@2: 
williamr@2: } // namespace detail
williamr@2: } // namespace boost
williamr@2: 
williamr@2: // In this section we supply the xxxx1 and xxxx2 forms of the operator
williamr@2: // templates, which are explicitly targeted at the 1-type-argument and
williamr@2: // 2-type-argument operator forms, respectively. Some compilers get confused
williamr@2: // when inline friend functions are overloaded in namespaces other than the
williamr@2: // global namespace. When BOOST_NO_OPERATORS_IN_NAMESPACE is defined, all of
williamr@2: // these templates must go in the global namespace.
williamr@2: 
williamr@2: #ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
williamr@2: namespace boost
williamr@2: {
williamr@2: #endif
williamr@2: 
williamr@2: //  Basic operator classes (contributed by Dave Abrahams) ------------------//
williamr@2: 
williamr@2: //  Note that friend functions defined in a class are implicitly inline.
williamr@2: //  See the C++ std, 11.4 [class.friend] paragraph 5
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct less_than_comparable2 : B
williamr@2: {
williamr@2:      friend bool operator<=(const T& x, const U& y) { return !(x > y); }
williamr@2:      friend bool operator>=(const T& x, const U& y) { return !(x < y); }
williamr@2:      friend bool operator>(const U& x, const T& y)  { return y < x; }
williamr@2:      friend bool operator<(const U& x, const T& y)  { return y > x; }
williamr@2:      friend bool operator<=(const U& x, const T& y) { return !(y < x); }
williamr@2:      friend bool operator>=(const U& x, const T& y) { return !(y > x); }
williamr@2: };
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct less_than_comparable1 : B
williamr@2: {
williamr@2:      friend bool operator>(const T& x, const T& y)  { return y < x; }
williamr@2:      friend bool operator<=(const T& x, const T& y) { return !(y < x); }
williamr@2:      friend bool operator>=(const T& x, const T& y) { return !(x < y); }
williamr@2: };
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct equality_comparable2 : B
williamr@2: {
williamr@2:      friend bool operator==(const U& y, const T& x) { return x == y; }
williamr@2:      friend bool operator!=(const U& y, const T& x) { return !(x == y); }
williamr@2:      friend bool operator!=(const T& y, const U& x) { return !(y == x); }
williamr@2: };
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct equality_comparable1 : B
williamr@2: {
williamr@2:      friend bool operator!=(const T& x, const T& y) { return !(x == y); }
williamr@2: };
williamr@2: 
williamr@2: // A macro which produces "name_2left" from "name".
williamr@2: #define BOOST_OPERATOR2_LEFT(name) name##2##_##left
williamr@2: 
williamr@2: //  NRVO-friendly implementation (contributed by Daniel Frey) ---------------//
williamr@2: 
williamr@2: #if defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
williamr@2: 
williamr@2: // This is the optimal implementation for ISO/ANSI C++,
williamr@2: // but it requires the compiler to implement the NRVO.
williamr@2: // If the compiler has no NRVO, this is the best symmetric
williamr@2: // implementation available.
williamr@2: 
williamr@2: #define BOOST_BINARY_OPERATOR_COMMUTATIVE( NAME, OP )                         \
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>            \
williamr@2: struct NAME##2 : B                                                            \
williamr@2: {                                                                             \
williamr@2:   friend T operator OP( const T& lhs, const U& rhs )                          \
williamr@2:     { T nrv( lhs ); nrv OP##= rhs; return nrv; }                              \
williamr@2:   friend T operator OP( const U& lhs, const T& rhs )                          \
williamr@2:     { T nrv( rhs ); nrv OP##= lhs; return nrv; }                              \
williamr@2: };                                                                            \
williamr@2:                                                                               \
williamr@2: template <class T, class B = ::boost::detail::empty_base>                     \
williamr@2: struct NAME##1 : B                                                            \
williamr@2: {                                                                             \
williamr@2:   friend T operator OP( const T& lhs, const T& rhs )                          \
williamr@2:     { T nrv( lhs ); nrv OP##= rhs; return nrv; }                              \
williamr@2: };
williamr@2: 
williamr@2: #define BOOST_BINARY_OPERATOR_NON_COMMUTATIVE( NAME, OP )           \
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>  \
williamr@2: struct NAME##2 : B                                                  \
williamr@2: {                                                                   \
williamr@2:   friend T operator OP( const T& lhs, const U& rhs )                \
williamr@2:     { T nrv( lhs ); nrv OP##= rhs; return nrv; }                    \
williamr@2: };                                                                  \
williamr@2:                                                                     \
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>  \
williamr@2: struct BOOST_OPERATOR2_LEFT(NAME) : B                               \
williamr@2: {                                                                   \
williamr@2:   friend T operator OP( const U& lhs, const T& rhs )                \
williamr@2:     { T nrv( lhs ); nrv OP##= rhs; return nrv; }                    \
williamr@2: };                                                                  \
williamr@2:                                                                     \
williamr@2: template <class T, class B = ::boost::detail::empty_base>           \
williamr@2: struct NAME##1 : B                                                  \
williamr@2: {                                                                   \
williamr@2:   friend T operator OP( const T& lhs, const T& rhs )                \
williamr@2:     { T nrv( lhs ); nrv OP##= rhs; return nrv; }                    \
williamr@2: };
williamr@2: 
williamr@2: #else // defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
williamr@2: 
williamr@2: // For compilers without NRVO the following code is optimal, but not
williamr@2: // symmetric!  Note that the implementation of
williamr@2: // BOOST_OPERATOR2_LEFT(NAME) only looks cool, but doesn't provide
williamr@2: // optimization opportunities to the compiler :)
williamr@2: 
williamr@2: #define BOOST_BINARY_OPERATOR_COMMUTATIVE( NAME, OP )                         \
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>            \
williamr@2: struct NAME##2 : B                                                            \
williamr@2: {                                                                             \
williamr@2:   friend T operator OP( T lhs, const U& rhs ) { return lhs OP##= rhs; }       \
williamr@2:   friend T operator OP( const U& lhs, T rhs ) { return rhs OP##= lhs; }       \
williamr@2: };                                                                            \
williamr@2:                                                                               \
williamr@2: template <class T, class B = ::boost::detail::empty_base>                     \
williamr@2: struct NAME##1 : B                                                            \
williamr@2: {                                                                             \
williamr@2:   friend T operator OP( T lhs, const T& rhs ) { return lhs OP##= rhs; }       \
williamr@2: };
williamr@2: 
williamr@2: #define BOOST_BINARY_OPERATOR_NON_COMMUTATIVE( NAME, OP )               \
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>      \
williamr@2: struct NAME##2 : B                                                      \
williamr@2: {                                                                       \
williamr@2:   friend T operator OP( T lhs, const U& rhs ) { return lhs OP##= rhs; } \
williamr@2: };                                                                      \
williamr@2:                                                                         \
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>      \
williamr@2: struct BOOST_OPERATOR2_LEFT(NAME) : B                                   \
williamr@2: {                                                                       \
williamr@2:   friend T operator OP( const U& lhs, const T& rhs )                    \
williamr@2:     { return T( lhs ) OP##= rhs; }                                      \
williamr@2: };                                                                      \
williamr@2:                                                                         \
williamr@2: template <class T, class B = ::boost::detail::empty_base>               \
williamr@2: struct NAME##1 : B                                                      \
williamr@2: {                                                                       \
williamr@2:   friend T operator OP( T lhs, const T& rhs ) { return lhs OP##= rhs; } \
williamr@2: };
williamr@2: 
williamr@2: #endif // defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
williamr@2: 
williamr@2: BOOST_BINARY_OPERATOR_COMMUTATIVE( multipliable, * )
williamr@2: BOOST_BINARY_OPERATOR_COMMUTATIVE( addable, + )
williamr@2: BOOST_BINARY_OPERATOR_NON_COMMUTATIVE( subtractable, - )
williamr@2: BOOST_BINARY_OPERATOR_NON_COMMUTATIVE( dividable, / )
williamr@2: BOOST_BINARY_OPERATOR_NON_COMMUTATIVE( modable, % )
williamr@2: BOOST_BINARY_OPERATOR_COMMUTATIVE( xorable, ^ )
williamr@2: BOOST_BINARY_OPERATOR_COMMUTATIVE( andable, & )
williamr@2: BOOST_BINARY_OPERATOR_COMMUTATIVE( orable, | )
williamr@2: 
williamr@2: #undef BOOST_BINARY_OPERATOR_COMMUTATIVE
williamr@2: #undef BOOST_BINARY_OPERATOR_NON_COMMUTATIVE
williamr@2: #undef BOOST_OPERATOR2_LEFT
williamr@2: 
williamr@2: //  incrementable and decrementable contributed by Jeremy Siek
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct incrementable : B
williamr@2: {
williamr@2:   friend T operator++(T& x, int)
williamr@2:   {
williamr@2:     incrementable_type nrv(x);
williamr@2:     ++x;
williamr@2:     return nrv;
williamr@2:   }
williamr@2: private: // The use of this typedef works around a Borland bug
williamr@2:   typedef T incrementable_type;
williamr@2: };
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct decrementable : B
williamr@2: {
williamr@2:   friend T operator--(T& x, int)
williamr@2:   {
williamr@2:     decrementable_type nrv(x);
williamr@2:     --x;
williamr@2:     return nrv;
williamr@2:   }
williamr@2: private: // The use of this typedef works around a Borland bug
williamr@2:   typedef T decrementable_type;
williamr@2: };
williamr@2: 
williamr@2: //  Iterator operator classes (contributed by Jeremy Siek) ------------------//
williamr@2: 
williamr@2: template <class T, class P, class B = ::boost::detail::empty_base>
williamr@2: struct dereferenceable : B
williamr@2: {
williamr@2:   P operator->() const
williamr@2:   { 
williamr@2:     return &*static_cast<const T&>(*this); 
williamr@2:   }
williamr@2: };
williamr@2: 
williamr@2: template <class T, class I, class R, class B = ::boost::detail::empty_base>
williamr@2: struct indexable : B
williamr@2: {
williamr@2:   R operator[](I n) const
williamr@2:   {
williamr@2:     return *(static_cast<const T&>(*this) + n);
williamr@2:   }
williamr@2: };
williamr@2: 
williamr@2: //  More operator classes (contributed by Daryle Walker) --------------------//
williamr@2: //  (NRVO-friendly implementation contributed by Daniel Frey) ---------------//
williamr@2: 
williamr@2: #if defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
williamr@2: 
williamr@2: #define BOOST_BINARY_OPERATOR( NAME, OP )                                     \
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>            \
williamr@2: struct NAME##2 : B                                                            \
williamr@2: {                                                                             \
williamr@2:   friend T operator OP( const T& lhs, const U& rhs )                          \
williamr@2:     { T nrv( lhs ); nrv OP##= rhs; return nrv; }                              \
williamr@2: };                                                                            \
williamr@2:                                                                               \
williamr@2: template <class T, class B = ::boost::detail::empty_base>                     \
williamr@2: struct NAME##1 : B                                                            \
williamr@2: {                                                                             \
williamr@2:   friend T operator OP( const T& lhs, const T& rhs )                          \
williamr@2:     { T nrv( lhs ); nrv OP##= rhs; return nrv; }                              \
williamr@2: };
williamr@2: 
williamr@2: #else // defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
williamr@2: 
williamr@2: #define BOOST_BINARY_OPERATOR( NAME, OP )                                     \
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>            \
williamr@2: struct NAME##2 : B                                                            \
williamr@2: {                                                                             \
williamr@2:   friend T operator OP( T lhs, const U& rhs ) { return lhs OP##= rhs; }       \
williamr@2: };                                                                            \
williamr@2:                                                                               \
williamr@2: template <class T, class B = ::boost::detail::empty_base>                     \
williamr@2: struct NAME##1 : B                                                            \
williamr@2: {                                                                             \
williamr@2:   friend T operator OP( T lhs, const T& rhs ) { return lhs OP##= rhs; }       \
williamr@2: };
williamr@2: 
williamr@2: #endif // defined(BOOST_HAS_NRVO) || defined(BOOST_FORCE_SYMMETRIC_OPERATORS)
williamr@2: 
williamr@2: BOOST_BINARY_OPERATOR( left_shiftable, << )
williamr@2: BOOST_BINARY_OPERATOR( right_shiftable, >> )
williamr@2: 
williamr@2: #undef BOOST_BINARY_OPERATOR
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct equivalent2 : B
williamr@2: {
williamr@2:   friend bool operator==(const T& x, const U& y)
williamr@2:   {
williamr@2:     return !(x < y) && !(x > y);
williamr@2:   }
williamr@2: };
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct equivalent1 : B
williamr@2: {
williamr@2:   friend bool operator==(const T&x, const T&y)
williamr@2:   {
williamr@2:     return !(x < y) && !(y < x);
williamr@2:   }
williamr@2: };
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct partially_ordered2 : B
williamr@2: {
williamr@2:   friend bool operator<=(const T& x, const U& y)
williamr@2:     { return (x < y) || (x == y); }
williamr@2:   friend bool operator>=(const T& x, const U& y)
williamr@2:     { return (x > y) || (x == y); }
williamr@2:   friend bool operator>(const U& x, const T& y)
williamr@2:     { return y < x; }
williamr@2:   friend bool operator<(const U& x, const T& y)
williamr@2:     { return y > x; }
williamr@2:   friend bool operator<=(const U& x, const T& y)
williamr@2:     { return (y > x) || (y == x); }
williamr@2:   friend bool operator>=(const U& x, const T& y)
williamr@2:     { return (y < x) || (y == x); }
williamr@2: };
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct partially_ordered1 : B
williamr@2: {
williamr@2:   friend bool operator>(const T& x, const T& y)
williamr@2:     { return y < x; }
williamr@2:   friend bool operator<=(const T& x, const T& y)
williamr@2:     { return (x < y) || (x == y); }
williamr@2:   friend bool operator>=(const T& x, const T& y)
williamr@2:     { return (y < x) || (x == y); }
williamr@2: };
williamr@2: 
williamr@2: //  Combined operator classes (contributed by Daryle Walker) ----------------//
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct totally_ordered2
williamr@2:     : less_than_comparable2<T, U
williamr@2:     , equality_comparable2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct totally_ordered1
williamr@2:     : less_than_comparable1<T
williamr@2:     , equality_comparable1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct additive2
williamr@2:     : addable2<T, U
williamr@2:     , subtractable2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct additive1
williamr@2:     : addable1<T
williamr@2:     , subtractable1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct multiplicative2
williamr@2:     : multipliable2<T, U
williamr@2:     , dividable2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct multiplicative1
williamr@2:     : multipliable1<T
williamr@2:     , dividable1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct integer_multiplicative2
williamr@2:     : multiplicative2<T, U
williamr@2:     , modable2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct integer_multiplicative1
williamr@2:     : multiplicative1<T
williamr@2:     , modable1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct arithmetic2
williamr@2:     : additive2<T, U
williamr@2:     , multiplicative2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct arithmetic1
williamr@2:     : additive1<T
williamr@2:     , multiplicative1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct integer_arithmetic2
williamr@2:     : additive2<T, U
williamr@2:     , integer_multiplicative2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct integer_arithmetic1
williamr@2:     : additive1<T
williamr@2:     , integer_multiplicative1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct bitwise2
williamr@2:     : xorable2<T, U
williamr@2:     , andable2<T, U
williamr@2:     , orable2<T, U, B
williamr@2:       > > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct bitwise1
williamr@2:     : xorable1<T
williamr@2:     , andable1<T
williamr@2:     , orable1<T, B
williamr@2:       > > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct unit_steppable
williamr@2:     : incrementable<T
williamr@2:     , decrementable<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct shiftable2
williamr@2:     : left_shiftable2<T, U
williamr@2:     , right_shiftable2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct shiftable1
williamr@2:     : left_shiftable1<T
williamr@2:     , right_shiftable1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct ring_operators2
williamr@2:     : additive2<T, U
williamr@2:     , subtractable2_left<T, U
williamr@2:     , multipliable2<T, U, B
williamr@2:       > > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct ring_operators1
williamr@2:     : additive1<T
williamr@2:     , multipliable1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct ordered_ring_operators2
williamr@2:     : ring_operators2<T, U
williamr@2:     , totally_ordered2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct ordered_ring_operators1
williamr@2:     : ring_operators1<T
williamr@2:     , totally_ordered1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct field_operators2
williamr@2:     : ring_operators2<T, U
williamr@2:     , dividable2<T, U
williamr@2:     , dividable2_left<T, U, B
williamr@2:       > > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct field_operators1
williamr@2:     : ring_operators1<T
williamr@2:     , dividable1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct ordered_field_operators2
williamr@2:     : field_operators2<T, U
williamr@2:     , totally_ordered2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct ordered_field_operators1
williamr@2:     : field_operators1<T
williamr@2:     , totally_ordered1<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct euclidian_ring_operators2
williamr@2:     : ring_operators2<T, U
williamr@2:     , dividable2<T, U
williamr@2:     , dividable2_left<T, U
williamr@2:     , modable2<T, U
williamr@2:     , modable2_left<T, U, B
williamr@2:       > > > > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct euclidian_ring_operators1
williamr@2:     : ring_operators1<T
williamr@2:     , dividable1<T
williamr@2:     , modable1<T, B
williamr@2:       > > > {};
williamr@2: 
williamr@2: template <class T, class U, class B = ::boost::detail::empty_base>
williamr@2: struct ordered_euclidian_ring_operators2
williamr@2:     : totally_ordered2<T, U
williamr@2:     , euclidian_ring_operators2<T, U, B
williamr@2:       > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct ordered_euclidian_ring_operators1
williamr@2:     : totally_ordered1<T
williamr@2:     , euclidian_ring_operators1<T, B
williamr@2:       > > {};
williamr@2:       
williamr@2: template <class T, class P, class B = ::boost::detail::empty_base>
williamr@2: struct input_iteratable
williamr@2:     : equality_comparable1<T
williamr@2:     , incrementable<T
williamr@2:     , dereferenceable<T, P, B
williamr@2:       > > > {};
williamr@2: 
williamr@2: template <class T, class B = ::boost::detail::empty_base>
williamr@2: struct output_iteratable
williamr@2:     : incrementable<T, B
williamr@2:       > {};
williamr@2: 
williamr@2: template <class T, class P, class B = ::boost::detail::empty_base>
williamr@2: struct forward_iteratable
williamr@2:     : input_iteratable<T, P, B
williamr@2:       > {};
williamr@2: 
williamr@2: template <class T, class P, class B = ::boost::detail::empty_base>
williamr@2: struct bidirectional_iteratable
williamr@2:     : forward_iteratable<T, P
williamr@2:     , decrementable<T, B
williamr@2:       > > {};
williamr@2: 
williamr@2: //  To avoid repeated derivation from equality_comparable,
williamr@2: //  which is an indirect base class of bidirectional_iterable,
williamr@2: //  random_access_iteratable must not be derived from totally_ordered1
williamr@2: //  but from less_than_comparable1 only. (Helmut Zeisel, 02-Dec-2001)
williamr@2: template <class T, class P, class D, class R, class B = ::boost::detail::empty_base>
williamr@2: struct random_access_iteratable
williamr@2:     : bidirectional_iteratable<T, P
williamr@2:     , less_than_comparable1<T
williamr@2:     , additive2<T, D
williamr@2:     , indexable<T, D, R, B
williamr@2:       > > > > {};
williamr@2: 
williamr@2: #ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
williamr@2: } // namespace boost
williamr@2: #endif // BOOST_NO_OPERATORS_IN_NAMESPACE
williamr@2: 
williamr@2: 
williamr@2: // BOOST_IMPORT_TEMPLATE1 .. BOOST_IMPORT_TEMPLATE4 -
williamr@2: //
williamr@2: // When BOOST_NO_OPERATORS_IN_NAMESPACE is defined we need a way to import an
williamr@2: // operator template into the boost namespace. BOOST_IMPORT_TEMPLATE1 is used
williamr@2: // for one-argument forms of operator templates; BOOST_IMPORT_TEMPLATE2 for
williamr@2: // two-argument forms. Note that these macros expect to be invoked from within
williamr@2: // boost.
williamr@2: 
williamr@2: #ifndef BOOST_NO_OPERATORS_IN_NAMESPACE
williamr@2: 
williamr@2:   // The template is already in boost so we have nothing to do.
williamr@2: # define BOOST_IMPORT_TEMPLATE4(template_name)
williamr@2: # define BOOST_IMPORT_TEMPLATE3(template_name)
williamr@2: # define BOOST_IMPORT_TEMPLATE2(template_name)
williamr@2: # define BOOST_IMPORT_TEMPLATE1(template_name)
williamr@2: 
williamr@2: #else // BOOST_NO_OPERATORS_IN_NAMESPACE
williamr@2: 
williamr@2: #  ifndef BOOST_NO_USING_TEMPLATE
williamr@2: 
williamr@2:      // Bring the names in with a using-declaration
williamr@2:      // to avoid stressing the compiler.
williamr@2: #    define BOOST_IMPORT_TEMPLATE4(template_name) using ::template_name;
williamr@2: #    define BOOST_IMPORT_TEMPLATE3(template_name) using ::template_name;
williamr@2: #    define BOOST_IMPORT_TEMPLATE2(template_name) using ::template_name;
williamr@2: #    define BOOST_IMPORT_TEMPLATE1(template_name) using ::template_name;
williamr@2: 
williamr@2: #  else
williamr@2: 
williamr@2:      // Otherwise, because a Borland C++ 5.5 bug prevents a using declaration
williamr@2:      // from working, we are forced to use inheritance for that compiler.
williamr@2: #    define BOOST_IMPORT_TEMPLATE4(template_name)                                          \
williamr@2:      template <class T, class U, class V, class W, class B = ::boost::detail::empty_base>  \
williamr@2:      struct template_name : ::template_name<T, U, V, W, B> {};
williamr@2: 
williamr@2: #    define BOOST_IMPORT_TEMPLATE3(template_name)                                 \
williamr@2:      template <class T, class U, class V, class B = ::boost::detail::empty_base>  \
williamr@2:      struct template_name : ::template_name<T, U, V, B> {};
williamr@2: 
williamr@2: #    define BOOST_IMPORT_TEMPLATE2(template_name)                              \
williamr@2:      template <class T, class U, class B = ::boost::detail::empty_base>        \
williamr@2:      struct template_name : ::template_name<T, U, B> {};
williamr@2: 
williamr@2: #    define BOOST_IMPORT_TEMPLATE1(template_name)                              \
williamr@2:      template <class T, class B = ::boost::detail::empty_base>                 \
williamr@2:      struct template_name : ::template_name<T, B> {};
williamr@2: 
williamr@2: #  endif // BOOST_NO_USING_TEMPLATE
williamr@2: 
williamr@2: #endif // BOOST_NO_OPERATORS_IN_NAMESPACE
williamr@2: 
williamr@2: //
williamr@2: // Here's where we put it all together, defining the xxxx forms of the templates
williamr@2: // in namespace boost. We also define specializations of is_chained_base<> for
williamr@2: // the xxxx, xxxx1, and xxxx2 templates, importing them into boost:: as
williamr@2: // necessary.
williamr@2: //
williamr@2: #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2: 
williamr@2: // is_chained_base<> - a traits class used to distinguish whether an operator
williamr@2: // template argument is being used for base class chaining, or is specifying a
williamr@2: // 2nd argument type.
williamr@2: 
williamr@2: namespace boost {
williamr@2: // A type parameter is used instead of a plain bool because Borland's compiler
williamr@2: // didn't cope well with the more obvious non-type template parameter.
williamr@2: namespace detail {
williamr@2:   struct true_t {};
williamr@2:   struct false_t {};
williamr@2: } // namespace detail
williamr@2: 
williamr@2: // Unspecialized version assumes that most types are not being used for base
williamr@2: // class chaining. We specialize for the operator templates defined in this
williamr@2: // library.
williamr@2: template<class T> struct is_chained_base {
williamr@2:   typedef ::boost::detail::false_t value;
williamr@2: };
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: // Import a 4-type-argument operator template into boost (if necessary) and
williamr@2: // provide a specialization of 'is_chained_base<>' for it.
williamr@2: # define BOOST_OPERATOR_TEMPLATE4(template_name4)                     \
williamr@2:   BOOST_IMPORT_TEMPLATE4(template_name4)                              \
williamr@2:   template<class T, class U, class V, class W, class B>               \
williamr@2:   struct is_chained_base< ::boost::template_name4<T, U, V, W, B> > {  \
williamr@2:     typedef ::boost::detail::true_t value;                            \
williamr@2:   };
williamr@2: 
williamr@2: // Import a 3-type-argument operator template into boost (if necessary) and
williamr@2: // provide a specialization of 'is_chained_base<>' for it.
williamr@2: # define BOOST_OPERATOR_TEMPLATE3(template_name3)                     \
williamr@2:   BOOST_IMPORT_TEMPLATE3(template_name3)                              \
williamr@2:   template<class T, class U, class V, class B>                        \
williamr@2:   struct is_chained_base< ::boost::template_name3<T, U, V, B> > {     \
williamr@2:     typedef ::boost::detail::true_t value;                            \
williamr@2:   };
williamr@2: 
williamr@2: // Import a 2-type-argument operator template into boost (if necessary) and
williamr@2: // provide a specialization of 'is_chained_base<>' for it.
williamr@2: # define BOOST_OPERATOR_TEMPLATE2(template_name2)                  \
williamr@2:   BOOST_IMPORT_TEMPLATE2(template_name2)                           \
williamr@2:   template<class T, class U, class B>                              \
williamr@2:   struct is_chained_base< ::boost::template_name2<T, U, B> > {     \
williamr@2:     typedef ::boost::detail::true_t value;                         \
williamr@2:   };
williamr@2: 
williamr@2: // Import a 1-type-argument operator template into boost (if necessary) and
williamr@2: // provide a specialization of 'is_chained_base<>' for it.
williamr@2: # define BOOST_OPERATOR_TEMPLATE1(template_name1)                  \
williamr@2:   BOOST_IMPORT_TEMPLATE1(template_name1)                           \
williamr@2:   template<class T, class B>                                       \
williamr@2:   struct is_chained_base< ::boost::template_name1<T, B> > {        \
williamr@2:     typedef ::boost::detail::true_t value;                         \
williamr@2:   };
williamr@2: 
williamr@2: // BOOST_OPERATOR_TEMPLATE(template_name) defines template_name<> such that it
williamr@2: // can be used for specifying both 1-argument and 2-argument forms. Requires the
williamr@2: // existence of two previously defined class templates named '<template_name>1'
williamr@2: // and '<template_name>2' which must implement the corresponding 1- and 2-
williamr@2: // argument forms.
williamr@2: //
williamr@2: // The template type parameter O == is_chained_base<U>::value is used to
williamr@2: // distinguish whether the 2nd argument to <template_name> is being used for
williamr@2: // base class chaining from another boost operator template or is describing a
williamr@2: // 2nd operand type. O == true_t only when U is actually an another operator
williamr@2: // template from the library. Partial specialization is used to select an
williamr@2: // implementation in terms of either '<template_name>1' or '<template_name>2'.
williamr@2: //
williamr@2: 
williamr@2: # define BOOST_OPERATOR_TEMPLATE(template_name)                    \
williamr@2: template <class T                                                  \
williamr@2:          ,class U = T                                              \
williamr@2:          ,class B = ::boost::detail::empty_base                    \
williamr@2:          ,class O = typename is_chained_base<U>::value             \
williamr@2:          >                                                         \
williamr@2: struct template_name : template_name##2<T, U, B> {};               \
williamr@2:                                                                    \
williamr@2: template<class T, class U, class B>                                \
williamr@2: struct template_name<T, U, B, ::boost::detail::true_t>             \
williamr@2:   : template_name##1<T, U> {};                                     \
williamr@2:                                                                    \
williamr@2: template <class T, class B>                                        \
williamr@2: struct template_name<T, T, B, ::boost::detail::false_t>            \
williamr@2:   : template_name##1<T, B> {};                                     \
williamr@2:                                                                    \
williamr@2: template<class T, class U, class B, class O>                       \
williamr@2: struct is_chained_base< ::boost::template_name<T, U, B, O> > {     \
williamr@2:   typedef ::boost::detail::true_t value;                           \
williamr@2: };                                                                 \
williamr@2:                                                                    \
williamr@2: BOOST_OPERATOR_TEMPLATE2(template_name##2)                         \
williamr@2: BOOST_OPERATOR_TEMPLATE1(template_name##1)
williamr@2: 
williamr@2: 
williamr@2: #else // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2: 
williamr@2: #  define BOOST_OPERATOR_TEMPLATE4(template_name4) \
williamr@2:         BOOST_IMPORT_TEMPLATE4(template_name4)
williamr@2: #  define BOOST_OPERATOR_TEMPLATE3(template_name3) \
williamr@2:         BOOST_IMPORT_TEMPLATE3(template_name3)
williamr@2: #  define BOOST_OPERATOR_TEMPLATE2(template_name2) \
williamr@2:         BOOST_IMPORT_TEMPLATE2(template_name2)
williamr@2: #  define BOOST_OPERATOR_TEMPLATE1(template_name1) \
williamr@2:         BOOST_IMPORT_TEMPLATE1(template_name1)
williamr@2: 
williamr@2:    // In this case we can only assume that template_name<> is equivalent to the
williamr@2:    // more commonly needed template_name1<> form.
williamr@2: #  define BOOST_OPERATOR_TEMPLATE(template_name)                   \
williamr@2:    template <class T, class B = ::boost::detail::empty_base>       \
williamr@2:    struct template_name : template_name##1<T, B> {};
williamr@2: 
williamr@2: #endif // BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2: 
williamr@2: namespace boost {
williamr@2:     
williamr@2: BOOST_OPERATOR_TEMPLATE(less_than_comparable)
williamr@2: BOOST_OPERATOR_TEMPLATE(equality_comparable)
williamr@2: BOOST_OPERATOR_TEMPLATE(multipliable)
williamr@2: BOOST_OPERATOR_TEMPLATE(addable)
williamr@2: BOOST_OPERATOR_TEMPLATE(subtractable)
williamr@2: BOOST_OPERATOR_TEMPLATE2(subtractable2_left)
williamr@2: BOOST_OPERATOR_TEMPLATE(dividable)
williamr@2: BOOST_OPERATOR_TEMPLATE2(dividable2_left)
williamr@2: BOOST_OPERATOR_TEMPLATE(modable)
williamr@2: BOOST_OPERATOR_TEMPLATE2(modable2_left)
williamr@2: BOOST_OPERATOR_TEMPLATE(xorable)
williamr@2: BOOST_OPERATOR_TEMPLATE(andable)
williamr@2: BOOST_OPERATOR_TEMPLATE(orable)
williamr@2: 
williamr@2: BOOST_OPERATOR_TEMPLATE1(incrementable)
williamr@2: BOOST_OPERATOR_TEMPLATE1(decrementable)
williamr@2: 
williamr@2: BOOST_OPERATOR_TEMPLATE2(dereferenceable)
williamr@2: BOOST_OPERATOR_TEMPLATE3(indexable)
williamr@2: 
williamr@2: BOOST_OPERATOR_TEMPLATE(left_shiftable)
williamr@2: BOOST_OPERATOR_TEMPLATE(right_shiftable)
williamr@2: BOOST_OPERATOR_TEMPLATE(equivalent)
williamr@2: BOOST_OPERATOR_TEMPLATE(partially_ordered)
williamr@2: 
williamr@2: BOOST_OPERATOR_TEMPLATE(totally_ordered)
williamr@2: BOOST_OPERATOR_TEMPLATE(additive)
williamr@2: BOOST_OPERATOR_TEMPLATE(multiplicative)
williamr@2: BOOST_OPERATOR_TEMPLATE(integer_multiplicative)
williamr@2: BOOST_OPERATOR_TEMPLATE(arithmetic)
williamr@2: BOOST_OPERATOR_TEMPLATE(integer_arithmetic)
williamr@2: BOOST_OPERATOR_TEMPLATE(bitwise)
williamr@2: BOOST_OPERATOR_TEMPLATE1(unit_steppable)
williamr@2: BOOST_OPERATOR_TEMPLATE(shiftable)
williamr@2: BOOST_OPERATOR_TEMPLATE(ring_operators)
williamr@2: BOOST_OPERATOR_TEMPLATE(ordered_ring_operators)
williamr@2: BOOST_OPERATOR_TEMPLATE(field_operators)
williamr@2: BOOST_OPERATOR_TEMPLATE(ordered_field_operators)
williamr@2: BOOST_OPERATOR_TEMPLATE(euclidian_ring_operators)
williamr@2: BOOST_OPERATOR_TEMPLATE(ordered_euclidian_ring_operators)
williamr@2: BOOST_OPERATOR_TEMPLATE2(input_iteratable)
williamr@2: BOOST_OPERATOR_TEMPLATE1(output_iteratable)
williamr@2: BOOST_OPERATOR_TEMPLATE2(forward_iteratable)
williamr@2: BOOST_OPERATOR_TEMPLATE2(bidirectional_iteratable)
williamr@2: BOOST_OPERATOR_TEMPLATE4(random_access_iteratable)
williamr@2: 
williamr@2: #undef BOOST_OPERATOR_TEMPLATE
williamr@2: #undef BOOST_OPERATOR_TEMPLATE4
williamr@2: #undef BOOST_OPERATOR_TEMPLATE3
williamr@2: #undef BOOST_OPERATOR_TEMPLATE2
williamr@2: #undef BOOST_OPERATOR_TEMPLATE1
williamr@2: #undef BOOST_IMPORT_TEMPLATE1
williamr@2: #undef BOOST_IMPORT_TEMPLATE2
williamr@2: #undef BOOST_IMPORT_TEMPLATE3
williamr@2: #undef BOOST_IMPORT_TEMPLATE4
williamr@2: 
williamr@2: // The following 'operators' classes can only be used portably if the derived class
williamr@2: // declares ALL of the required member operators.
williamr@2: template <class T, class U>
williamr@2: struct operators2
williamr@2:     : totally_ordered2<T,U
williamr@2:     , integer_arithmetic2<T,U
williamr@2:     , bitwise2<T,U
williamr@2:       > > > {};
williamr@2: 
williamr@2: #ifndef BOOST_NO_TEMPLATE_PARTIAL_SPECIALIZATION
williamr@2: template <class T, class U = T>
williamr@2: struct operators : operators2<T, U> {};
williamr@2: 
williamr@2: template <class T> struct operators<T, T>
williamr@2: #else
williamr@2: template <class T> struct operators
williamr@2: #endif
williamr@2:     : totally_ordered<T
williamr@2:     , integer_arithmetic<T
williamr@2:     , bitwise<T
williamr@2:     , unit_steppable<T
williamr@2:       > > > > {};
williamr@2: 
williamr@2: //  Iterator helper classes (contributed by Jeremy Siek) -------------------//
williamr@2: //  (Input and output iterator helpers contributed by Daryle Walker) -------//
williamr@2: //  (Changed to use combined operator classes by Daryle Walker) ------------//
williamr@2: template <class T,
williamr@2:           class V,
williamr@2:           class D = std::ptrdiff_t,
williamr@2:           class P = V const *,
williamr@2:           class R = V const &>
williamr@2: struct input_iterator_helper
williamr@2:   : input_iteratable<T, P
williamr@2:   , boost::iterator<std::input_iterator_tag, V, D, P, R
williamr@2:     > > {};
williamr@2: 
williamr@2: template<class T>
williamr@2: struct output_iterator_helper
williamr@2:   : output_iteratable<T
williamr@2:   , boost::iterator<std::output_iterator_tag, void, void, void, void
williamr@2:   > >
williamr@2: {
williamr@2:   T& operator*()  { return static_cast<T&>(*this); }
williamr@2:   T& operator++() { return static_cast<T&>(*this); }
williamr@2: };
williamr@2: 
williamr@2: template <class T,
williamr@2:           class V,
williamr@2:           class D = std::ptrdiff_t,
williamr@2:           class P = V*,
williamr@2:           class R = V&>
williamr@2: struct forward_iterator_helper
williamr@2:   : forward_iteratable<T, P
williamr@2:   , boost::iterator<std::forward_iterator_tag, V, D, P, R
williamr@2:     > > {};
williamr@2: 
williamr@2: template <class T,
williamr@2:           class V,
williamr@2:           class D = std::ptrdiff_t,
williamr@2:           class P = V*,
williamr@2:           class R = V&>
williamr@2: struct bidirectional_iterator_helper
williamr@2:   : bidirectional_iteratable<T, P
williamr@2:   , boost::iterator<std::bidirectional_iterator_tag, V, D, P, R
williamr@2:     > > {};
williamr@2: 
williamr@2: template <class T,
williamr@2:           class V, 
williamr@2:           class D = std::ptrdiff_t,
williamr@2:           class P = V*,
williamr@2:           class R = V&>
williamr@2: struct random_access_iterator_helper
williamr@2:   : random_access_iteratable<T, P, D, R
williamr@2:   , boost::iterator<std::random_access_iterator_tag, V, D, P, R
williamr@2:     > >
williamr@2: {
williamr@2:   friend D requires_difference_operator(const T& x, const T& y) {
williamr@2:     return x - y;
williamr@2:   }
williamr@2: }; // random_access_iterator_helper
williamr@2: 
williamr@2: } // namespace boost
williamr@2: 
williamr@2: #if defined(__sgi) && !defined(__GNUC__)
williamr@2: #pragma reset woff 1234
williamr@2: #endif
williamr@2: 
williamr@2: #endif // BOOST_OPERATORS_HPP