libcxx/test/std/utilities/format/format.functions/vformat_to.pass.cpp

   1 //===----------------------------------------------------------------------===//
   2 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   3 // See https://llvm.org/LICENSE.txt for license information.
   4 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   5 //
   6 //===----------------------------------------------------------------------===//
   7
   8 // UNSUPPORTED: c++03, c++11, c++14, c++17
   9 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
  10
  11 // XFAIL: availability-fp_to_chars-missing
  12
  13 // <format>
  14
  15 // template<class Out>
  16 //   Out vformat_to(Out out, string_view fmt, format_args args);
  17 // template<class Out>
  18 //    Out vformat_to(Out out, wstring_view fmt, wformat_args_t args);
  19
  20 #include <format>
  21 #include <algorithm>
  22 #include <cassert>
  23 #include <list>
  24 #include <vector>
  25
  26 #include "assert_macros.h"
  27 #include "concat_macros.h"
  28 #include "test_macros.h"
  29 #include "format_tests.h"
  30 #include "string_literal.h"
  31
  32 auto test = []<class CharT, class... Args>(
  33                 std::basic_string_view<CharT> expected, std::basic_string_view<CharT> fmt, Args&&... args) constexpr {
  34   {
  35     std::basic_string<CharT> out(expected.size(), CharT(' '));
  36     auto it = std::vformat_to(out.begin(), fmt, std::make_format_args<context_t<CharT>>(args...));
  37     assert(it == out.end());
  38     assert(out == expected);
  39   }
  40   {
  41     std::list<CharT> out;
  42     std::vformat_to(std::back_inserter(out), fmt, std::make_format_args<context_t<CharT>>(args...));
  43     assert(std::equal(out.begin(), out.end(), expected.begin(), expected.end()));
  44   }
  45   {
  46     std::vector<CharT> out;
  47     std::vformat_to(std::back_inserter(out), fmt, std::make_format_args<context_t<CharT>>(args...));
  48     assert(std::equal(out.begin(), out.end(), expected.begin(), expected.end()));
  49   }
  50   {
  51     assert(expected.size() < 4096 && "Update the size of the buffer.");
  52     CharT out[4096];
  53     CharT* it = std::vformat_to(out, fmt, std::make_format_args<context_t<CharT>>(args...));
  54     assert(std::distance(out, it) == int(expected.size()));
  55     // Convert to std::string since output contains '\0' for boolean tests.
  56     assert(std::basic_string<CharT>(out, it) == expected);
  57   }
  58 };
  59
  60 auto test_exception =
  61     []<class CharT, class... Args>(
  62         [[maybe_unused]] std::string_view what,
  63         [[maybe_unused]] std::basic_string_view<CharT> fmt,
  64         [[maybe_unused]] Args&&... args) {
  65       TEST_VALIDATE_EXCEPTION(
  66           std::format_error,
  67           [&]([[maybe_unused]] const std::format_error& e) {
  68             TEST_LIBCPP_REQUIRE(
  69                 e.what() == what,
  70                 TEST_WRITE_CONCATENATED(
  71                     "\nFormat string   ", fmt, "\nExpected exception ", what, "\nActual exception   ", e.what(), '\n'));
  72           },
  73           [&] {
  74             std::basic_string<CharT> out;
  75             std::vformat_to(std::back_inserter(out), fmt, std::make_format_args<context_t<CharT>>(args...));
  76           }());
  77     };
  78
  79 int main(int, char**) {
  80   format_tests<char, execution_modus::partial>(test, test_exception);
  81
  82 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  83   format_tests_char_to_wchar_t(test);
  84   format_tests<wchar_t, execution_modus::partial>(test, test_exception);
  85 #endif
  86
  87   return 0;
  88 }