libcxx/test/std/containers/container.adaptors/container.adaptors.format/parse.pass.cpp

   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, c++20
  10
  11 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
  12
  13 // [container.adaptors.format]
  14 // For each of queue, priority_queue, and stack, the library provides the
  15 // following formatter specialization where adaptor-type is the name of the
  16 // template:
  17 //
  18 // template<class charT, class T, formattable<charT> Container, class... U>
  19 //   struct formatter<adaptor-type<T, Container, U...>, charT>
  20
  21 // template<class ParseContext>
  22 //   constexpr typename ParseContext::iterator
  23 //     parse(ParseContext& ctx);
  24
  25 // Note this tests the basics of this function. It's tested in more detail in
  26 // the format functions test.
  27
  28 #include <cassert>
  29 #include <concepts>
  30 #include <format>
  31 #include <memory>
  32 #include <queue>
  33 #include <stack>
  34
  35 #include "test_macros.h"
  36 #include "make_string.h"
  37
  38 #define SV(S) MAKE_STRING_VIEW(CharT, S)
  39
  40 template <class Arg, class StringViewT>
  41 constexpr void test_parse(StringViewT fmt, std::size_t offset) {
  42   using CharT    = typename StringViewT::value_type;
  43   auto parse_ctx = std::basic_format_parse_context<CharT>(fmt);
  44   std::formatter<Arg, CharT> formatter;
  45   static_assert(std::semiregular<decltype(formatter)>);
  46
  47   std::same_as<typename StringViewT::iterator> auto it = formatter.parse(parse_ctx);
  48   // std::to_address works around LWG3989 and MSVC STL's iterator debugging mechanism.
  49   assert(std::to_address(it) == std::to_address(fmt.end()) - offset);
  50 }
  51
  52 template <class StringViewT>
  53 constexpr void test_parse(StringViewT fmt, std::size_t offset) {
  54   test_parse<std::queue<int>>(fmt, offset);
  55   test_parse<std::priority_queue<int>>(fmt, offset);
  56   test_parse<std::stack<int>>(fmt, offset);
  57 }
  58
  59 template <class CharT>
  60 constexpr void test_fmt() {
  61   test_parse(SV(""), 0);
  62   test_parse(SV(":d"), 0);
  63
  64   test_parse(SV("}"), 1);
  65   test_parse(SV(":d}"), 1);
  66 }
  67
  68 constexpr bool test() {
  69   test_fmt<char>();
  70 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  71   test_fmt<wchar_t>();
  72 #endif
  73
  74   return true;
  75 }
  76
  77 int main(int, char**) {
  78   test();
  79   static_assert(test());
  80
  81   return 0;
  82 }