The Battle for Wesnoth  1.17.4+dev
general.hpp
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1 /*
2  Copyright (C) 2003 - 2022
3  Part of the Battle for Wesnoth Project https://www.wesnoth.org/
4 
5  This program is free software; you can redistribute it and/or modify
6  it under the terms of the GNU General Public License as published by
7  the Free Software Foundation; either version 2 of the License, or
8  (at your option) any later version.
9  This program is distributed in the hope that it will be useful,
10  but WITHOUT ANY WARRANTY.
11 
12  See the COPYING file for more details.
13 */
14 
15 #pragma once
16 
17 #include <algorithm>
18 #include <cctype>
19 #include <functional>
20 
21 namespace utils
22 {
23 inline bool chars_equal_insensitive(char a, char b) { return tolower(a) == tolower(b); }
24 inline bool chars_less_insensitive(char a, char b) { return tolower(a) < tolower(b); }
25 
26 /**
27  * Equivalent to as @c std::is_same_v except both types are passed through std::decay first.
28  *
29  * @tparam T1 The first type to compare.
30  * @tparam T2 The second type to compare.
31  */
32 template<typename T1, typename T2>
33 inline constexpr bool decayed_is_same = std::is_same_v<std::decay_t<T1>, std::decay_t<T2>>;
34 
35 /**
36  * Workaround for the fact that static_assert(false) is invalid.
37  * See https://devblogs.microsoft.com/oldnewthing/20200311-00/?p=103553
38  */
39 template<typename>
40 inline constexpr bool dependent_false_v = false;
41 
42 namespace detail
43 {
44 /**
45  * A struct that exists to implement a generic wrapper for std::find.
46  * Container should "look like" an STL container of Values.
47  */
48 template<typename Container, typename Value>
50 {
51  static bool eval(const Container& container, const Value& value)
52  {
53  typename Container::const_iterator end = container.end();
54  return std::find(container.begin(), end, value) != end;
55  }
56 };
57 
58 /**
59  * A struct that exists to implement a generic wrapper for the find()
60  * member of associative containers.
61  * Container should "look like" an STL associative container.
62  */
63 template<typename Container>
64 struct contains_impl<Container, typename Container::key_type>
65 {
66  static bool eval(const Container& container, const typename Container::key_type& value)
67  {
68  return container.find(value) != container.end();
69  }
70 };
71 
72 } // namespace detail
73 
74 /**
75  * Returns true iff @a value is found in @a container.
76  *
77  * This should work whenever Container "looks like" an STL container of Values.
78  * Normally this uses std::find(), but a simulated partial template specialization
79  * exists when Value is Container::key_type. In this case, Container is assumed
80  * an associative container, and the member function find() is used.
81  */
82 template<typename Container, typename Value>
83 inline bool contains(const Container& container, const Value& value)
84 {
85  return detail::contains_impl<Container, Value>::eval(container, value);
86 }
87 
88 } // namespace utils
static bool eval(const Container &container, const typename Container::key_type &value)
Definition: general.hpp:66
#define a
bool chars_equal_insensitive(char a, char b)
Definition: general.hpp:23
constexpr bool dependent_false_v
Workaround for the fact that static_assert(false) is invalid.
Definition: general.hpp:40
bool contains(const Container &container, const Value &value)
Returns true iff value is found in container.
Definition: general.hpp:83
#define b
constexpr bool decayed_is_same
Equivalent to as std::is_same_v except both types are passed through std::decay first.
Definition: general.hpp:33
static bool eval(const Container &container, const Value &value)
Definition: general.hpp:51
A struct that exists to implement a generic wrapper for std::find.
Definition: general.hpp:49
bool chars_less_insensitive(char a, char b)
Definition: general.hpp:24