| 1 | // Copyright (C) 2003, Fernando Luis Cacciola Carballal. |
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| 2 | // |
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| 3 | // Use, modification, and distribution is subject to the Boost Software |
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| 4 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
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| 5 | // http://www.boost.org/LICENSE_1_0.txt) |
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| 6 | // |
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| 7 | // See http://www.boost.org/libs/optional for documentation. |
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| 8 | // |
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| 9 | // You are welcome to contact the author at: |
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| 10 | // fernando_cacciola@hotmail.com |
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| 11 | // |
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| 12 | #ifndef BOOST_UTILITY_COMPARE_POINTEES_25AGO2003_HPP |
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| 13 | #define BOOST_UTILITY_COMPARE_POINTEES_25AGO2003_HPP |
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| 14 | |
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| 15 | #include<functional> |
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| 16 | |
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| 17 | namespace boost { |
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| 18 | |
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| 19 | // template<class OP> bool equal_pointees(OP const& x, OP const& y); |
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| 20 | // template<class OP> struct equal_pointees_t; |
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| 21 | // |
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| 22 | // Being OP a model of OptionalPointee (either a pointer or an optional): |
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| 23 | // |
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| 24 | // If both x and y have valid pointees, returns the result of (*x == *y) |
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| 25 | // If only one has a valid pointee, returns false. |
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| 26 | // If none have valid pointees, returns true. |
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| 27 | // No-throw |
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| 28 | template<class OptionalPointee> |
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| 29 | inline |
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| 30 | bool equal_pointees ( OptionalPointee const& x, OptionalPointee const& y ) |
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| 31 | { |
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| 32 | return (!x) != (!y) ? false : ( !x ? true : (*x) == (*y) ) ; |
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| 33 | } |
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| 34 | |
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| 35 | template<class OptionalPointee> |
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| 36 | struct equal_pointees_t |
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| 37 | { |
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| 38 | typedef bool result_type; |
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| 39 | typedef OptionalPointee first_argument_type; |
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| 40 | typedef OptionalPointee second_argument_type; |
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| 41 | |
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| 42 | bool operator() ( OptionalPointee const& x, OptionalPointee const& y ) const |
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| 43 | { return equal_pointees(x,y) ; } |
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| 44 | } ; |
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| 45 | |
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| 46 | // template<class OP> bool less_pointees(OP const& x, OP const& y); |
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| 47 | // template<class OP> struct less_pointees_t; |
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| 48 | // |
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| 49 | // Being OP a model of OptionalPointee (either a pointer or an optional): |
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| 50 | // |
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| 51 | // If y has not a valid pointee, returns false. |
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| 52 | // ElseIf x has not a valid pointee, returns true. |
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| 53 | // ElseIf both x and y have valid pointees, returns the result of (*x < *y) |
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| 54 | // No-throw |
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| 55 | template<class OptionalPointee> |
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| 56 | inline |
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| 57 | bool less_pointees ( OptionalPointee const& x, OptionalPointee const& y ) |
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| 58 | { |
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| 59 | return !y ? false : ( !x ? true : (*x) < (*y) ) ; |
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| 60 | } |
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| 61 | |
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| 62 | template<class OptionalPointee> |
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| 63 | struct less_pointees_t |
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| 64 | { |
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| 65 | typedef bool result_type; |
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| 66 | typedef OptionalPointee first_argument_type; |
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| 67 | typedef OptionalPointee second_argument_type; |
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| 68 | |
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| 69 | bool operator() ( OptionalPointee const& x, OptionalPointee const& y ) const |
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| 70 | { return less_pointees(x,y) ; } |
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| 71 | } ; |
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| 72 | |
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| 73 | } // namespace boost |
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| 74 | |
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| 75 | #endif |
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| 76 | |
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| 77 | |
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