xref: /llvm-project/libcxx/test/std/utilities/format/format.functions/vformat_to.pass.cpp (revision 6a54dfbfe534276d644d7f9c027f0deeb748dd53)
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, c++17
10 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
11 
12 // XFAIL: availability-fp_to_chars-missing
13 
14 // <format>
15 
16 // template<class Out>
17 //   Out vformat_to(Out out, string_view fmt, format_args args);
18 // template<class Out>
19 //    Out vformat_to(Out out, wstring_view fmt, wformat_args_t args);
20 
21 #include <format>
22 #include <algorithm>
23 #include <cassert>
24 #include <list>
25 #include <vector>
26 
27 #include "assert_macros.h"
28 #include "concat_macros.h"
29 #include "test_macros.h"
30 #include "format_tests.h"
31 #include "string_literal.h"
32 
33 auto test = []<class CharT, class... Args>(
34                 std::basic_string_view<CharT> expected, std::basic_string_view<CharT> fmt, Args&&... args) constexpr {
35   {
36     std::basic_string<CharT> out(expected.size(), CharT(' '));
37     auto it = std::vformat_to(out.begin(), fmt, std::make_format_args<context_t<CharT>>(args...));
38     assert(it == out.end());
39     assert(out == expected);
40   }
41   {
42     std::list<CharT> out;
43     std::vformat_to(std::back_inserter(out), fmt, std::make_format_args<context_t<CharT>>(args...));
44     assert(std::equal(out.begin(), out.end(), expected.begin(), expected.end()));
45   }
46   {
47     std::vector<CharT> out;
48     std::vformat_to(std::back_inserter(out), fmt, std::make_format_args<context_t<CharT>>(args...));
49     assert(std::equal(out.begin(), out.end(), expected.begin(), expected.end()));
50   }
51   {
52     assert(expected.size() < 4096 && "Update the size of the buffer.");
53     CharT out[4096];
54     CharT* it = std::vformat_to(out, fmt, std::make_format_args<context_t<CharT>>(args...));
55     assert(std::distance(out, it) == int(expected.size()));
56     // Convert to std::string since output contains '\0' for boolean tests.
57     assert(std::basic_string<CharT>(out, it) == expected);
58   }
59 };
60 
61 auto test_exception =
62     []<class CharT, class... Args>(
63         [[maybe_unused]] std::string_view what,
64         [[maybe_unused]] std::basic_string_view<CharT> fmt,
65         [[maybe_unused]] Args&&... args) {
66       TEST_VALIDATE_EXCEPTION(
67           std::format_error,
68           [&]([[maybe_unused]] const std::format_error& e) {
69             TEST_LIBCPP_REQUIRE(
70                 e.what() == what,
71                 TEST_WRITE_CONCATENATED(
72                     "\nFormat string   ", fmt, "\nExpected exception ", what, "\nActual exception   ", e.what(), '\n'));
73           },
74           [&] {
75             std::basic_string<CharT> out;
76             std::vformat_to(std::back_inserter(out), fmt, std::make_format_args<context_t<CharT>>(args...));
77           }());
78     };
79 
80 int main(int, char**) {
81   format_tests<char, execution_modus::partial>(test, test_exception);
82 
83 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
84   format_tests_char_to_wchar_t(test);
85   format_tests<wchar_t, execution_modus::partial>(test, test_exception);
86 #endif
87 
88   return 0;
89 }
90