//===----------------------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//
#ifndef TEST_SUPPORT_FORMAT_FUNCTIONS_COMMON_H
#define TEST_SUPPORT_FORMAT_FUNCTIONS_COMMON_H
// Contains the common part of the formatter tests for different papers.
#include <algorithm>
#include <cctype>
#include <charconv>
#include <cstddef>
#include <cstdint>
#include <cstdlib>
#include <format>
#include <ranges>
#include <string_view>
#include <string>
#include <vector>
#include "make_string.h"
#define STR(S) MAKE_STRING(CharT, S)
#define SV(S) MAKE_STRING_VIEW(CharT, S)
#define CSTR(S) MAKE_CSTRING(CharT, S)
template <class T>
struct context {};
template <>
struct context<char> {
using type = std::format_context;
};
#ifndef TEST_HAS_NO_WIDE_CHARACTERS
template <>
struct context<wchar_t> {
using type = std::wformat_context;
};
#endif
template <class T>
using context_t = typename context<T>::type;
// A user-defined type used to test the handle formatter.
enum class status : std::uint16_t { foo = 0xAAAA, bar = 0x5555, foobar = 0xAA55 };
// The formatter for a user-defined type used to test the handle formatter.
template <class CharT>
struct std::formatter<status, CharT> {
// During the 2023 Issaquah meeting LEWG made it clear a formatter is
// required to call its parse function. LWG3892 Adds the wording for that
// requirement. Therefore this formatter is initialized in an invalid state.
// A call to parse sets it in a valid state and a call to format validates
// the state.
int type = -1;
constexpr auto parse(basic_format_parse_context<CharT>& parse_ctx) -> decltype(parse_ctx.begin()) {
auto begin = parse_ctx.begin();
auto end = parse_ctx.end();
type = 0;
if (begin == end)
return begin;
switch (*begin) {
case CharT('x'):
break;
case CharT('X'):
type = 1;
break;
case CharT('s'):
type = 2;
break;
case CharT('}'):
return begin;
default:
throw_format_error("The type option contains an invalid value for a status formatting argument");
}
++begin;
if (begin != end && *begin != CharT('}'))
throw_format_error("The format specifier should consume the input or end with a '}'");
return begin;
}
template <class Out>
auto format(status s, basic_format_context<Out, CharT>& ctx) const -> decltype(ctx.out()) {
const char* names[] = {"foo", "bar", "foobar"};
char buffer[7];
const char* begin = names[0];
const char* end = names[0];
switch (type) {
case -1:
throw_format_error("The formatter's parse function has not been called.");
case 0:
begin = buffer;
buffer[0] = '0';
buffer[1] = 'x';
end = std::to_chars(&buffer[2], std::end(buffer), static_cast<std::uint16_t>(s), 16).ptr;
buffer[6] = '\0';
break;
case 1:
begin = buffer;
buffer[0] = '0';
buffer[1] = 'X';
end = std::to_chars(&buffer[2], std::end(buffer), static_cast<std::uint16_t>(s), 16).ptr;
std::transform(static_cast<const char*>(&buffer[2]), end, &buffer[2], [](char c) {
return static_cast<char>(std::toupper(c)); });
buffer[6] = '\0';
break;
case 2:
switch (s) {
case status::foo:
begin = names[0];
break;
case status::bar:
begin = names[1];
break;
case status::foobar:
begin = names[2];
break;
}
end = begin + strlen(begin);
break;
}
return std::copy(begin, end, ctx.out());
}
private:
[[noreturn]] void throw_format_error([[maybe_unused]] const char* s) const {
#ifndef TEST_HAS_NO_EXCEPTIONS
throw std::format_error(s);
#else
std::abort();
#endif
}
};
struct parse_call_validator {
struct parse_function_not_called {};
friend constexpr auto operator<=>(const parse_call_validator& lhs, const parse_call_validator& rhs) {
return &lhs <=> &rhs;
}
};
// The formatter for a user-defined type used to test the handle formatter.
//
// Like std::formatter<status, CharT> this formatter validates that parse is
// called. This formatter is intended to be used when the formatter's parse is
// called directly and not with format. In that case the format-spec does not
// require a terminating }. The tests must be written in a fashion where this
// formatter is always called with an empty format-spec. This requirement
// allows testing of certain code paths that are never reached by using a
// well-formed format-string in the format functions.
template <class CharT>
struct std::formatter<parse_call_validator, CharT> {
bool parse_called{false};
constexpr auto parse(basic_format_parse_context<CharT>& parse_ctx) -> decltype(parse_ctx.begin()) {
auto begin = parse_ctx.begin();
auto end = parse_ctx.end();
assert(begin == end);
parse_called = true;
return begin;
}
auto format(parse_call_validator, auto& ctx) const -> decltype(ctx.out()) {
if (!parse_called)
throw_error<parse_call_validator::parse_function_not_called>();
return ctx.out();
}
private:
template <class T>
[[noreturn]] void throw_error() const {
#ifndef TEST_HAS_NO_EXCEPTIONS
throw T{};
#else
std::abort();
#endif
}
};
// Creates format string for the invalid types.
//
// valid contains a list of types that are valid.
// - The type ?s is the only type requiring 2 characters, use S for that type.
// - Whether n is a type or not depends on the context, is is always used.
//
// The return value is a collection of basic_strings, instead of
// basic_string_views since the values are temporaries.
namespace detail {
template <class CharT, std::size_t N>
std::basic_string<CharT> get_colons() {
static std::basic_string<CharT> result(N, CharT(':'));
return result;
}
constexpr std::string_view get_format_types() {
return "aAbBcdeEfFgGopPsxX"
#if TEST_STD_VER > 20
"?"
#endif
;
}
template <class CharT, /*format_types types,*/ size_t N>
std::vector<std::basic_string<CharT>> fmt_invalid_types(std::string_view valid) {
// std::ranges::to is not available in C++20.
std::vector<std::basic_string<CharT>> result;
std::ranges::copy(
get_format_types() | std::views::filter([&](char type) { return valid.find(type) == std::string_view::npos; }) |
std::views::transform([&](char type) { return std::format(SV("{{{}{}}}"), get_colons<CharT, N>(), type); }),
std::back_inserter(result));
return result;
}
} // namespace detail
// Creates format string for the invalid types.
//
// valid contains a list of types that are valid.
//
// The return value is a collection of basic_strings, instead of
// basic_string_views since the values are temporaries.
template <class CharT>
std::vector<std::basic_string<CharT>> fmt_invalid_types(std::string_view valid) {
return detail::fmt_invalid_types<CharT, 1>(valid);
}
// Like fmt_invalid_types but when the format spec is for an underlying formatter.
template <class CharT>
std::vector<std::basic_string<CharT>> fmt_invalid_nested_types(std::string_view valid) {
return detail::fmt_invalid_types<CharT, 2>(valid);
}
#endif // TEST_SUPPORT_FORMAT_FUNCTIONS_COMMON_H
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