support/char_set/range_functions.hpp

0001 /*=============================================================================
0002     Copyright (c) 2001-2011 Joel de Guzman
0003
0004     Distributed under the Boost Software License, Version 1.0. (See accompanying
0005     file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
0006 ==============================================================================*/
0007 #if !defined(BOOST_SPIRIT_RANGE_FUNCTIONS_MAY_16_2006_0720_PM)
0008 #define BOOST_SPIRIT_RANGE_FUNCTIONS_MAY_16_2006_0720_PM
0009
0010 #if defined(_MSC_VER)
0011 #pragma once
0012 #endif
0013
0014 #include <limits>
0015
0016 namespace boost { namespace spirit { namespace support { namespace detail
0017 {
0018     template <typename Range>
0019     inline bool
0020     is_valid(Range const& range)
0021     {
0022         // test for valid ranges
0023         return range.first <= range.last;
0024     }
0025
0026     template <typename Range>
0027     inline bool
0028     includes(Range const& range, Range const& other)
0029     {
0030         // see if two ranges intersect
0031         return (range.first <= other.first) && (range.last >= other.last);
0032     }
0033
0034     template <typename Range>
0035     inline bool
0036     includes(Range const& range, typename Range::value_type val)
0037     {
0038         // see if val is in range
0039         return (range.first <= val) && (range.last >= val);
0040     }
0041
0042     template <typename Range>
0043     inline bool
0044     can_merge(Range const& range, Range const& other)
0045     {
0046         // see if a 'range' overlaps, or is adjacent to
0047         // another range 'other', so we can merge them
0048
0049         typedef typename Range::value_type value_type;
0050         typedef std::numeric_limits<value_type> limits;
0051
0052         value_type decr_first =
0053             range.first == (limits::min)()
0054             ? range.first : range.first-1;
0055
0056         value_type incr_last =
0057             range.last == (limits::max)()
0058             ? range.last : range.last+1;
0059
0060         return (decr_first <= other.last) && (incr_last >= other.first);
0061     }
0062
0063     template <typename Range>
0064     inline void
0065     merge(Range& result, Range const& other)
0066     {
0067         // merge two ranges
0068         if (result.first > other.first)
0069             result.first = other.first;
0070         if (result.last < other.last)
0071             result.last = other.last;
0072     }
0073
0074     template <typename Range>
0075     struct range_compare
0076     {
0077         // compare functor with a value or another range
0078
0079         typedef typename Range::value_type value_type;
0080
0081         bool operator()(Range const& x, const value_type y) const
0082         {
0083             return x.first < y;
0084         }
0085
0086         bool operator()(value_type const x, Range const& y) const
0087         {
0088             return x < y.first;
0089         }
0090
0091         bool operator()(Range const& x, Range const& y) const
0092         {
0093             return x.first < y.first;
0094         }
0095     };
0096 }}}}
0097
0098 #endif