1//===----------------------------------------------------------------------===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9// UNSUPPORTED: c++03, c++11, c++14
10
11// <charconv>
12
13// constexpr from_chars_result from_chars(const char* first, const char* last,
14// Integral& value, int base = 10)
15
16#include <charconv>
17#include <system_error>
18
19#include "test_macros.h"
20#include "charconv_test_helpers.h"
21
22template <typename T>
23struct test_basics
24{
25 TEST_CONSTEXPR_CXX23 void operator()()
26 {
27 std::from_chars_result r;
28 T x;
29
30 {
31 char s[] = "001x";
32
33 // the expected form of the subject sequence is a sequence of
34 // letters and digits representing an integer with the radix
35 // specified by base (C11 7.22.1.4/3)
36 r = std::from_chars(s, s + sizeof(s), x);
37 assert(r.ec == std::errc{});
38 assert(r.ptr == s + 3);
39 assert(x == 1);
40 }
41
42 {
43 // The string has more characters than valid in an 128-bit value.
44 char s[] = "0X7BAtSGHDkEIXZgQRfYChLpOzRnM ";
45
46 // The letters from a (or A) through z (or Z) are ascribed the
47 // values 10 through 35; (C11 7.22.1.4/3)
48 r = std::from_chars(s, s + sizeof(s), x, 36);
49 assert(r.ec == std::errc::result_out_of_range);
50 // The member ptr of the return value points to the first character
51 // not matching the pattern
52 assert(r.ptr == s + sizeof(s) - 2);
53 assert(x == 1);
54
55 // no "0x" or "0X" prefix shall appear if the value of base is 16
56 r = std::from_chars(s, s + sizeof(s), x, 16);
57 assert(r.ec == std::errc{});
58 assert(r.ptr == s + 1);
59 assert(x == 0);
60
61 // only letters and digits whose ascribed values are less than that
62 // of base are permitted. (C11 7.22.1.4/3)
63 r = std::from_chars(s + 2, s + sizeof(s), x, 12);
64 // If the parsed value is not in the range representable by the type
65 // of value,
66 if (!fits_in<T>(1150))
67 {
68 // value is unmodified and
69 assert(x == 0);
70 // the member ec of the return value is equal to
71 // errc::result_out_of_range
72 assert(r.ec == std::errc::result_out_of_range);
73 }
74 else
75 {
76 // Otherwise, value is set to the parsed value,
77 assert(x == 1150);
78 // and the member ec is value-initialized.
79 assert(r.ec == std::errc{});
80 }
81 assert(r.ptr == s + 5);
82 }
83 }
84};
85
86template <typename T>
87struct test_signed
88{
89 TEST_CONSTEXPR_CXX23 void operator()()
90 {
91 std::from_chars_result r;
92 T x = 42;
93
94 {
95 // If the pattern allows for an optional sign,
96 // but the string has no digit characters following the sign,
97 char s[] = "- 9+12";
98 r = std::from_chars(s, s + sizeof(s), x);
99 // value is unmodified,
100 assert(x == 42);
101 // no characters match the pattern.
102 assert(r.ptr == s);
103 assert(r.ec == std::errc::invalid_argument);
104 }
105
106 {
107 char s[] = "9+12";
108 r = std::from_chars(s, s + sizeof(s), x);
109 assert(r.ec == std::errc{});
110 // The member ptr of the return value points to the first character
111 // not matching the pattern,
112 assert(r.ptr == s + 1);
113 assert(x == 9);
114 }
115
116 {
117 char s[] = "12";
118 r = std::from_chars(s, s + 2, x);
119 assert(r.ec == std::errc{});
120 // or has the value last if all characters match.
121 assert(r.ptr == s + 2);
122 assert(x == 12);
123 }
124
125 {
126 // '-' is the only sign that may appear
127 char s[] = "+30";
128 // If no characters match the pattern,
129 r = std::from_chars(s, s + sizeof(s), x);
130 // value is unmodified,
131 assert(x == 12);
132 // the member ptr of the return value is first and
133 assert(r.ptr == s);
134 // the member ec is equal to errc::invalid_argument.
135 assert(r.ec == std::errc::invalid_argument);
136 }
137 }
138};
139
140TEST_CONSTEXPR_CXX23 bool test()
141{
142 run<test_basics>(integrals);
143 run<test_signed>(all_signed);
144
145 return true;
146}
147
148int main(int, char**) {
149 test();
150#if TEST_STD_VER > 20
151 static_assert(test());
152#endif
153
154 return 0;
155}
156

source code of libcxx/test/std/utilities/charconv/charconv.from.chars/integral.pass.cpp