libcxx/test/std/containers/container.adaptors/container.adaptors.format/format.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, c++20
   9
  10 // UNSUPPORTED: GCC-ALWAYS_INLINE-FIXME
  11
  12 // [container.adaptors.format]
  13 // For each of queue, priority_queue, and stack, the library provides the
  14 // following formatter specialization where adaptor-type is the name of the
  15 // template:
  16 //
  17 // template<class charT, class T, formattable<charT> Container, class... U>
  18 //   struct formatter<adaptor-type<T, Container, U...>, charT>
  19
  20 // template<class FormatContext>
  21 //   typename FormatContext::iterator
  22 //     format(maybe-const-adaptor& r, FormatContext& ctx) const;
  23
  24 // Note this tests the basics of this function. It's tested in more detail in
  25 // the format functions test.
  26
  27 #include <array>
  28 #include <cassert>
  29 #include <concepts>
  30 #include <format>
  31 #include <queue>
  32 #include <stack>
  33
  34 #include "test_format_context.h"
  35 #include "test_macros.h"
  36 #include "make_string.h"
  37
  38 #define SV(S) MAKE_STRING_VIEW(CharT, S)
  39
  40 template <class StringViewT, class Arg>
  41 void test_format(StringViewT expected, Arg arg) {
  42   using CharT      = typename StringViewT::value_type;
  43   using String     = std::basic_string<CharT>;
  44   using OutIt      = std::back_insert_iterator<String>;
  45   using FormatCtxT = std::basic_format_context<OutIt, CharT>;
  46
  47   const std::formatter<Arg, CharT> formatter;
  48
  49   String result;
  50   OutIt out             = std::back_inserter(result);
  51   FormatCtxT format_ctx = test_format_context_create<OutIt, CharT>(out, std::make_format_args<FormatCtxT>(arg));
  52   formatter.format(arg, format_ctx);
  53   assert(result == expected);
  54 }
  55
  56 template <class CharT>
  57 void test_fmt() {
  58   std::array input{1, 42, 99, 0};
  59   test_format(SV("[1, 42, 99, 0]"), std::queue<int>{input.begin(), input.end()});
  60   test_format(SV("[99, 42, 1, 0]"), std::priority_queue<int>{input.begin(), input.end()});
  61   test_format(SV("[1, 42, 99, 0]"), std::stack<int>{input.begin(), input.end()});
  62 }
  63
  64 void test() {
  65   test_fmt<char>();
  66 #ifndef TEST_HAS_NO_WIDE_CHARACTERS
  67   test_fmt<wchar_t>();
  68 #endif
  69 }
  70
  71 int main(int, char**) {
  72   test();
  73
  74   return 0;
  75 }