The Battle for Wesnoth  1.17.0-dev
string_utils.hpp
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1 /*
2  Copyright (C) 2005 - 2021
3  by Guillaume Melquiond <guillaume.melquiond@gmail.com>
4  Copyright (C) 2003 by David White <dave@whitevine.net>
5  Part of the Battle for Wesnoth Project https://www.wesnoth.org/
6 
7  This program is free software; you can redistribute it and/or modify
8  it under the terms of the GNU General Public License as published by
9  the Free Software Foundation; either version 2 of the License, or
10  (at your option) any later version.
11  This program is distributed in the hope that it will be useful,
12  but WITHOUT ANY WARRANTY.
13 
14  See the COPYING file for more details.
15 */
16 
17 #pragma once
18 
19 // Need this to get the default GETTEXT_DOMAIN for VGETTEXT/VNGETTEXT
20 #include "gettext.hpp"
21 
23 
24 #include <ctime>
25 
26 class variable_set;
27 
28 namespace utils {
29 
30  namespace detail {
31  extern std::string(* evaluate_formula)(const std::string& formula);
32  }
33 
34 /**
35  * Determines if a string might contain variables to interpolate.
36  * This can allow one to skip future interpolations (plural -- if there is only
37  * one interpolation, the savings are not worth this check). In this spirit,
38  * precision is sacrificed in the name of efficiency; the check is quick and
39  * allows false positives, but there are no false negatives. (A false negative
40  * would lead to incorrect behavior, whereas a false positive leads to merely
41  * inefficient behavior.) In practice, false positives should be uncommon enough
42  * to not worry about.
43  */
44 inline bool might_contain_variables(const std::string &str)
45 { return str.find('$') != std::string::npos; }
46 
47 /**
48  * Function which will interpolate variables, starting with '$' in the string
49  * 'str' with the equivalent symbols in the given symbol table. If 'symbols'
50  * is nullptr, then game event variables will be used instead.
51  */
52 std::string interpolate_variables_into_string(const std::string &str, const string_map * const symbols);
53 std::string interpolate_variables_into_string(const std::string &str, const std::map<std::string,std::string> * const symbols);
54 std::string interpolate_variables_into_string(const std::string &str, const variable_set& variables);
55 
56 /**
57  * Function that does the same as the above, for t_stringS.
58  * If a change was made, then the t_string's translation is done in this
59  * function, rather than at use. This limitation is due to the use of
60  * create-time interpolation, rather than use-time.
61  */
63 
64 /**
65  * Format a conjunctive list.
66  * @param empty The string to return for an empty list
67  * @param elems The list of entries in the list
68  * @return The elements of the list joined by "and".
69  */
70 std::string format_conjunct_list(const t_string& empty, const std::vector<t_string>& elems);
71 
72 /**
73  * Format a disjunctive list.
74  * @param empty The string to return for an empty list
75  * @param elems The list of entries in the list
76  * @return The elements of the list joined or "and".
77  */
78 std::string format_disjunct_list(const t_string& empty, const std::vector<t_string>& elems);
79 
80 /**
81  * Formats a timespan into human-readable text for player authentication functions.
82  *
83  * This is intentionally not a very thorough representation of time intervals.
84  * See <https://github.com/wesnoth/wesnoth/issues/6036> for more information.
85  *
86  * @param time The timespan in seconds.
87  * @param detailed Whether to display more specific values such as "3 months, 2 days,
88  * 30 minutes, and 1 second". If not specified or set to @a false, the
89  * return value will ONLY include most significant time unit (e.g. "3
90  * months").
91  * @return A human-readable timespan description.
92  *
93  * @note The implementation is not very precise because not all months in the Gregorian
94  * calendar have 30 days. Furthermore, it doesn't take into account leap years or
95  * leap seconds. If you need to account for those, you are better off importing
96  * a new library and providing it with more specific information about the start and
97  * end times of the interval; otherwise your next best option is to hire a fortune
98  * teller to manually service your requests every time instead of this function.
99  */
100 std::string format_timespan(std::time_t time, bool detailed = false);
101 }
102 
103 /**
104  * Implementation functions for the VGETTEXT and VNGETTEXT macros.
105  *
106  * DO NOT USE DIRECTLY unless you really know what you're doing.
107  * See https://github.com/wesnoth/wesnoth/issues/2716 for more info.
108  */
109 
110 std::string vgettext_impl(const char* domain, const char* msgid, const utils::string_map& symbols);
111 
112 std::string vngettext_impl(const char* domain,
113  const char* singular,
114  const char* plural,
115  int count,
116  const utils::string_map& symbols);
117 
118 /**
119  * Handy wrappers around interpolate_variables_into_string and gettext.
120  *
121  * These should cover most usecases. If you're not sure whether you want
122  * these macros or their implementation functions, use these. The only time
123  * you should need to use the implementation functions directly is to pass a
124  * different textdomain than the current value of GETTEXT_DOMAIN.
125  */
126 
127 #define VGETTEXT(msgid, ...) \
128  vgettext_impl(GETTEXT_DOMAIN, msgid, __VA_ARGS__)
129 
130 #define VNGETTEXT(msgid, msgid_plural, count, ...) \
131  vngettext_impl(GETTEXT_DOMAIN, msgid, msgid_plural, count, __VA_ARGS__)
std::string format_conjunct_list(const t_string &empty, const std::vector< t_string > &elems)
Format a conjunctive list.
std::string interpolate_variables_into_string(const std::string &str, const string_map *const symbols)
Function which will interpolate variables, starting with &#39;$&#39; in the string &#39;str&#39; with the equivalent ...
std::map< std::string, t_string > string_map
std::string format_disjunct_list(const t_string &empty, const std::vector< t_string > &elems)
Format a disjunctive list.
std::string vgettext_impl(const char *domain, const char *msgid, const utils::string_map &symbols)
Implementation functions for the VGETTEXT and VNGETTEXT macros.
std::string format_timespan(std::time_t time, bool detailed)
Formats a timespan into human-readable text for player authentication functions.
std::string(* evaluate_formula)(const std::string &formula)
std::string vngettext_impl(const char *domain, const char *singular, const char *plural, int count, const utils::string_map &symbols)
bool might_contain_variables(const std::string &str)
Determines if a string might contain variables to interpolate.
t_string interpolate_variables_into_tstring(const t_string &tstr, const variable_set &variables)
Function that does the same as the above, for t_stringS.