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comparison cpp/to_int/to_int.hpp @ 626:64884a4de16a

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to_int: initial import
author David Demelier <markand@malikania.fr>
date Thu, 26 Oct 2017 19:45:00 +0200
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children b327391f6a62
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625:dccaf66c8b9f 626:64884a4de16a
1 /*
2 * to_int.hpp -- safely convert string to integers
3 *
4 * Copyright (c) 2016-2017 David Demelier <markand@malikania.fr>
5 *
6 * Permission to use, copy, modify, and/or distribute this software for any
7 * purpose with or without fee is hereby granted, provided that the above
8 * copyright notice and this permission notice appear in all copies.
9 *
10 * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
11 * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
12 * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
13 * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
14 * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
15 * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
16 * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
17 */
18
19 #ifndef TO_INT_HPP
20 #define TO_INT_HPP
21
22 /**
23 * \file to_int.hpp
24 * \brief Safely convert string to integers.
25 */
26
27 #include <cassert>
28 #include <limits>
29 #include <sstream>
30 #include <stdexcept>
31 #include <string>
32 #include <type_traits>
33
34 /**
35 * \cond HIDDEN_SYMBOLS
36 */
37
38 namespace detail {
39
40 std::invalid_argument make_invalid_argument(const std::string& str)
41 {
42 std::ostringstream oss;
43
44 oss << "invalid number '" << str << "'";
45
46 return std::invalid_argument(oss.str());
47 }
48
49 template <typename T>
50 std::out_of_range make_out_of_range(const std::string& str, T min, T max)
51 {
52 std::ostringstream oss;
53
54 oss << "number '" << str << "' is out of range ";
55 oss << min << ".." << max;
56
57 return std::out_of_range(oss.str());
58 }
59
60 } // !detail
61
62 /**
63 * \endcond
64 */
65
66 /**
67 * Convert the given string into a signed integer.
68 *
69 * \param str the string to convert
70 * \param min the minimum value allowed
71 * \param max the maximum value allowed
72 * \throw std::invalid_argument if the number was not parsed
73 * \throw std::out_or_range if the argument is out of the specified range
74 */
75 template <typename T = int>
76 T to_int(const std::string& str, T min = std::numeric_limits<T>::min(), T max = std::numeric_limits<T>::max())
77 {
78 static_assert(std::is_signed<T>::value, "must be signed");
79
80 char* end;
81 auto v = std::strtoll(str.c_str(), &end, 10);
82
83 if (*end != '\0')
84 throw detail::make_invalid_argument(str);
85 if (v < min || v > max)
86 throw detail::make_out_of_range(str, min, max);
87
88 return static_cast<T>(v);
89 }
90
91 /**
92 * Convert the given string into an unsigned integer.
93 *
94 * In contrast to the [std::strtoull][strtoull] function, this functions
95 * verifies if the string starts with minus sign and throws an exception if any.
96 *
97 * Note, for this you need to have a trimmed string which contains no leading
98 * whitespaces.
99 *
100 * \pre string must be trimmed
101 * \param str the string to convert
102 * \param min the minimum value allowed
103 * \param max the maximum value allowed
104 * \throw std::invalid_argument if the number was not parsed
105 * \throw std::out_or_range if the argument is out of the specified range
106 *
107 * [strtoull]: http://en.cppreference.com/w/cpp/string/byte/strtoul
108 */
109 template <typename T = unsigned>
110 T to_uint(const std::string& str, T min = std::numeric_limits<T>::min(), T max = std::numeric_limits<T>::max())
111 {
112 static_assert(std::is_unsigned<T>::value, "must be unsigned");
113
114 assert(str.empty() || !std::isspace(str[0]));
115
116 if (str.size() > 0U && str[0] == '-')
117 throw detail::make_out_of_range(str, min, max);
118
119 char* end;
120 auto v = std::strtoull(str.c_str(), &end, 10);
121
122 if (*end != '\0')
123 throw detail::make_invalid_argument(str);
124 if (v < min || v > max)
125 throw detail::make_out_of_range(str, min, max);
126
127 return v;
128 }
129
130 #endif // !TO_INT_HPP