| //===----------------------------------------------------------------------===// |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| // UNSUPPORTED: c++03, c++11, c++14, c++17 |
| // UNSUPPORTED: libcpp-has-no-incomplete-format |
| |
| // <format> |
| |
| // A user defined formatter using |
| // template<class Context> |
| // class basic_format_arg<Context>::handle |
| |
| #include <format> |
| |
| #include <array> |
| #include <cassert> |
| #include <cmath> |
| #include <charconv> |
| #include <concepts> |
| #include <iterator> |
| #include <string> |
| #include <type_traits> |
| |
| #include "test_format_context.h" |
| #include "test_macros.h" |
| |
| enum class color { black, red, gold }; |
| const char* color_names[] = {"black", "red", "gold"}; |
| |
| template <> |
| struct std::formatter<color> : std::formatter<const char*> { |
| auto format(color c, auto& ctx) const { |
| return formatter<const char*>::format(color_names[static_cast<int>(c)], ctx); |
| } |
| }; |
| |
| void test(std::string expected, std::string_view fmt, color arg, std::size_t offset) { |
| auto parse_ctx = std::format_parse_context(fmt); |
| std::formatter<color, char> formatter; |
| static_assert(std::semiregular<decltype(formatter)>); |
| |
| auto it = formatter.parse(parse_ctx); |
| assert(it == fmt.end() - offset); |
| |
| std::string result; |
| auto out = std::back_inserter(result); |
| using FormatCtxT = std::basic_format_context<decltype(out), char>; |
| |
| FormatCtxT format_ctx = |
| test_format_context_create<decltype(out), char>(out, std::make_format_args<FormatCtxT>(arg)); |
| formatter.format(arg, format_ctx); |
| assert(result == expected); |
| } |
| |
| void test_termination_condition(std::string expected, std::string f, color arg) { |
| // The format-spec is valid if completely consumed or terminates at a '}'. |
| // The valid inputs all end with a '}'. The test is executed twice: |
| // - first with the terminating '}', |
| // - second consuming the entire input. |
| std::string_view fmt{f}; |
| assert(fmt.back() == '}' && "Pre-condition failure"); |
| |
| test(expected, fmt, arg, 1); |
| fmt.remove_suffix(1); |
| test(expected, fmt, arg, 0); |
| } |
| |
| int main(int, char**) { |
| test_termination_condition("black", "}", color::black); |
| test_termination_condition("red", "}", color::red); |
| test_termination_condition("gold", "}", color::gold); |
| |
| return 0; |
| } |