include/o3tl/strong_int.hxx

   1 /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
   2 /*
   3  * This file is part of the LibreOffice project.
   4  *
   5  * This Source Code Form is subject to the terms of the Mozilla Public
   6  * License, v. 2.0. If a copy of the MPL was not distributed with this
   7  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
   8  *
   9  * This file incorporates work covered by the following license notice:
  10  *
  11  *   Licensed to the Apache Software Foundation (ASF) under one or more
  12  *   contributor license agreements. See the NOTICE file distributed
  13  *   with this work for additional information regarding copyright
  14  *   ownership. The ASF licenses this file to you under the Apache
  15  *   License, Version 2.0 (the "License"); you may not use this file
  16  *   except in compliance with the License. You may obtain a copy of
  17  *   the License at http://www.apache.org/licenses/LICENSE-2.0 .
  18  */
  19
  20 #ifndef INCLUDED_O3TL_STRONG_INT_HXX
  21 #define INCLUDED_O3TL_STRONG_INT_HXX
  22
  23 #include <sal/config.h>
  24 #include <limits>
  25 #include <cassert>
  26 #include <type_traits>
  27
  28 namespace o3tl
  29 {
  30
  31 #if !defined __COVERITY__
  32
  33 namespace detail {
  34
  35 template<typename T1, typename T2> constexpr
  36 typename std::enable_if<
  37     std::is_signed<T1>::value && std::is_signed<T2>::value, bool>::type
  38 isInRange(T2 value) {
  39     return value >= std::numeric_limits<T1>::min()
  40         && value <= std::numeric_limits<T1>::max();
  41 }
  42
  43 template<typename T1, typename T2> constexpr
  44 typename std::enable_if<
  45     std::is_signed<T1>::value && std::is_unsigned<T2>::value, bool>::type
  46 isInRange(T2 value) {
  47     return value
  48         <= static_cast<typename std::make_unsigned<T1>::type>(
  49             std::numeric_limits<T1>::max());
  50 }
  51
  52 template<typename T1, typename T2> constexpr
  53 typename std::enable_if<
  54     std::is_unsigned<T1>::value && std::is_signed<T2>::value, bool>::type
  55 isInRange(T2 value) {
  56     return value >= 0
  57         && (static_cast<typename std::make_unsigned<T2>::type>(value)
  58             <= std::numeric_limits<T1>::max());
  59 }
  60
  61 template<typename T1, typename T2> constexpr
  62 typename std::enable_if<
  63     std::is_unsigned<T1>::value && std::is_unsigned<T2>::value, bool>::type
  64 isInRange(T2 value) {
  65     return value <= std::numeric_limits<T1>::max();
  66 }
  67
  68 }
  69
  70 #endif
  71
  72 ///
  73 /// Wrap up an integer type so that we prevent accidental conversion to other integer types.
  74 ///
  75 /// e.g.
  76 ///   typedef o3tl::strong_int<unsigned, struct MyIntTag> MyInt;
  77 ///
  78 /// \param UNDERLYING_TYPE the underlying scalar type
  79 /// \param PHANTOM_TYPE    a type tag, used to distinguish this instantiation of the template
  80 ///                        from other instantiations with the same UNDERLYING_TYPE.
  81 ///
  82 template <typename UNDERLYING_TYPE, typename PHANTOM_TYPE>
  83 struct strong_int
  84 {
  85 public:
  86     template<typename T> explicit constexpr strong_int(
  87         T value,
  88         typename std::enable_if<std::is_integral<T>::value, int>::type = 0):
  89         m_value(value)
  90     {
  91 #if !defined __COVERITY__
  92         // catch attempts to pass in out-of-range values early
  93         assert(detail::isInRange<UNDERLYING_TYPE>(value)
  94                && "out of range");
  95 #endif
  96     }
  97     strong_int() : m_value(0) {}
  98
  99     explicit constexpr operator UNDERLYING_TYPE() const { return m_value; }
 100     explicit operator bool() const { return m_value != 0; }
 101     UNDERLYING_TYPE get() const { return m_value; }
 102
 103     bool operator<(strong_int const & other) const { return m_value < other.m_value; }
 104     bool operator<=(strong_int const & other) const { return m_value <= other.m_value; }
 105     bool operator>(strong_int const & other) const { return m_value > other.m_value; }
 106     bool operator>=(strong_int const & other) const { return m_value >= other.m_value; }
 107     bool operator==(strong_int const & other) const { return m_value == other.m_value; }
 108     bool operator!=(strong_int const & other) const { return m_value != other.m_value; }
 109     strong_int& operator++() { ++m_value; return *this; }
 110     strong_int operator++(int) { UNDERLYING_TYPE nOldValue = m_value; ++m_value; return strong_int(nOldValue); }
 111     strong_int& operator--() { --m_value; return *this; }
 112     strong_int operator--(int) { UNDERLYING_TYPE nOldValue = m_value; --m_value; return strong_int(nOldValue); }
 113     strong_int& operator+=(strong_int const & other) { m_value += other.m_value; return *this; }
 114     strong_int& operator-=(strong_int const & other) { m_value -= other.m_value; return *this; }
 115     strong_int& operator%=(strong_int const & other) { m_value %= other.m_value; return *this; }
 116     strong_int& operator*=(strong_int const & other) { m_value *= other.m_value; return *this; }
 117     strong_int& operator/=(strong_int const & other) { m_value /= other.m_value; return *this; }
 118     [[nodiscard]]
 119     strong_int operator%(strong_int const & other) const { return strong_int(m_value % other.m_value); }
 120     [[nodiscard]]
 121     strong_int operator-() const { return strong_int(-m_value); }
 122     [[nodiscard]]
 123     strong_int operator*(strong_int const & other) const { return strong_int(m_value * other.m_value); }
 124     [[nodiscard]]
 125     strong_int operator/(strong_int const & other) const { return strong_int(m_value / other.m_value); }
 126
 127     bool anyOf(strong_int v) const {
 128       return *this == v;
 129     }
 130
 131     template<typename... Args>
 132     bool anyOf(strong_int first, Args... args) const {
 133       return *this == first || anyOf(args...);
 134     }
 135
 136 private:
 137     UNDERLYING_TYPE m_value;
 138 };
 139
 140 template <typename UT, typename PT>
 141 strong_int<UT,PT> operator+(strong_int<UT,PT> const & lhs, strong_int<UT,PT> const & rhs)
 142 {
 143     return strong_int<UT,PT>(lhs.get() + rhs.get());
 144 }
 145
 146 template <typename UT, typename PT>
 147 strong_int<UT,PT> operator-(strong_int<UT,PT> const & lhs, strong_int<UT,PT> const & rhs)
 148 {
 149     return strong_int<UT,PT>(lhs.get() - rhs.get());
 150 }
 151
 152 }; // namespace o3tl
 153
 154 #endif /* INCLUDED_O3TL_STRONG_INT_HXX */
 155
 156 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */