1 files changed, 410 insertions, 0 deletions
diff --git a/libcxx/include/__chrono/parser_std_format_spec.h b/libcxx/include/__chrono/parser_std_format_spec.h
new file mode 100644
index 000000000000..dbcfe6da608a
--- /dev/null
+++ b/libcxx/include/__chrono/parser_std_format_spec.h
@@ -0,0 +1,410 @@
+// -*- C++ -*-
+//===----------------------------------------------------------------------===//
+//
+// 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 _LIBCPP___CHRONO_PARSER_STD_FORMAT_SPEC_H
+#define _LIBCPP___CHRONO_PARSER_STD_FORMAT_SPEC_H
+
+#include <__config>
+#include <__format/concepts.h>
+#include <__format/format_error.h>
+#include <__format/format_parse_context.h>
+#include <__format/formatter_string.h>
+#include <__format/parser_std_format_spec.h>
+#include <string_view>
+
+#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
+#  pragma GCC system_header
+#endif
+
+_LIBCPP_BEGIN_NAMESPACE_STD
+
+#if _LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+
+namespace __format_spec {
+
+// By not placing this constant in the formatter class it's not duplicated for char and wchar_t
+inline constexpr __fields __fields_chrono_fractional{
+    .__precision_ = true, .__locale_specific_form_ = true, .__type_ = false};
+inline constexpr __fields __fields_chrono{.__locale_specific_form_ = true, .__type_ = false};
+
+/// Flags available or required in a chrono type.
+///
+/// The caller of the chrono formatter lists the types it has available and the
+/// validation tests whether the requested type spec (e.g. %M) is available in
+/// the formatter.
+/// When the type in the chrono-format-spec isn't present in the data a
+/// \ref format_error is thrown.
+enum class __flags {
+  __second = 0x1,
+  __minute = 0x2,
+  __hour   = 0x4,
+  __time   = __hour | __minute | __second,
+
+  __day   = 0x8,
+  __month = 0x10,
+  __year  = 0x20,
+
+  __weekday = 0x40,
+
+  __month_day     = __day | __month,
+  __month_weekday = __weekday | __month,
+  __year_month    = __month | __year,
+  __date          = __day | __month | __year | __weekday,
+
+  __date_time = __date | __time,
+
+  __duration = 0x80 | __time,
+
+  __time_zone = 0x100,
+
+  __clock = __date_time | __time_zone
+};
+
+_LIBCPP_HIDE_FROM_ABI constexpr __flags operator&(__flags __lhs, __flags __rhs) {
+  return static_cast<__flags>(static_cast<unsigned>(__lhs) & static_cast<unsigned>(__rhs));
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_second(__flags __flags) {
+  if ((__flags & __flags::__second) != __flags::__second)
+    std::__throw_format_error("The supplied date time doesn't contain a second");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_minute(__flags __flags) {
+  if ((__flags & __flags::__minute) != __flags::__minute)
+    std::__throw_format_error("The supplied date time doesn't contain a minute");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_hour(__flags __flags) {
+  if ((__flags & __flags::__hour) != __flags::__hour)
+    std::__throw_format_error("The supplied date time doesn't contain an hour");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_time(__flags __flags) {
+  if ((__flags & __flags::__time) != __flags::__time)
+    std::__throw_format_error("The supplied date time doesn't contain a time");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_day(__flags __flags) {
+  if ((__flags & __flags::__day) != __flags::__day)
+    std::__throw_format_error("The supplied date time doesn't contain a day");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_month(__flags __flags) {
+  if ((__flags & __flags::__month) != __flags::__month)
+    std::__throw_format_error("The supplied date time doesn't contain a month");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_year(__flags __flags) {
+  if ((__flags & __flags::__year) != __flags::__year)
+    std::__throw_format_error("The supplied date time doesn't contain a year");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_date(__flags __flags) {
+  if ((__flags & __flags::__date) != __flags::__date)
+    std::__throw_format_error("The supplied date time doesn't contain a date");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_date_or_duration(__flags __flags) {
+  if (((__flags & __flags::__date) != __flags::__date) && ((__flags & __flags::__duration) != __flags::__duration))
+    std::__throw_format_error("The supplied date time doesn't contain a date or duration");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_date_time(__flags __flags) {
+  if ((__flags & __flags::__date_time) != __flags::__date_time)
+    std::__throw_format_error("The supplied date time doesn't contain a date and time");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_weekday(__flags __flags) {
+  if ((__flags & __flags::__weekday) != __flags::__weekday)
+    std::__throw_format_error("The supplied date time doesn't contain a weekday");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_duration(__flags __flags) {
+  if ((__flags & __flags::__duration) != __flags::__duration)
+    std::__throw_format_error("The supplied date time doesn't contain a duration");
+}
+
+_LIBCPP_HIDE_FROM_ABI constexpr void __validate_time_zone(__flags __flags) {
+  if ((__flags & __flags::__time_zone) != __flags::__time_zone)
+    std::__throw_format_error("The supplied date time doesn't contain a time zone");
+}
+
+template <class _CharT>
+class _LIBCPP_TEMPLATE_VIS __parser_chrono {
+public:
+  _LIBCPP_HIDE_FROM_ABI constexpr auto
+  __parse(basic_format_parse_context<_CharT>& __parse_ctx, __fields __fields, __flags __flags)
+      -> decltype(__parse_ctx.begin()) {
+    const _CharT* __begin = __parser_.__parse(__parse_ctx, __fields);
+    const _CharT* __end   = __parse_ctx.end();
+    if (__begin == __end)
+      return __begin;
+
+    const _CharT* __last = __parse_chrono_specs(__begin, __end, __flags);
+    __chrono_specs_      = basic_string_view<_CharT>{__begin, __last};
+
+    return __last;
+  }
+
+  __parser<_CharT> __parser_;
+  basic_string_view<_CharT> __chrono_specs_;
+
+private:
+  _LIBCPP_HIDE_FROM_ABI constexpr const _CharT*
+  __parse_chrono_specs(const _CharT* __begin, const _CharT* __end, __flags __flags) {
+    _LIBCPP_ASSERT(__begin != __end,
+                   "When called with an empty input the function will cause "
+                   "undefined behavior by evaluating data not in the input");
+
+    if (*__begin != _CharT('%') && *__begin != _CharT('}'))
+      std::__throw_format_error("Expected '%' or '}' in the chrono format-string");
+
+    do {
+      switch (*__begin) {
+      case _CharT('{'):
+        std::__throw_format_error("The chrono-specs contains a '{'");
+
+      case _CharT('}'):
+        return __begin;
+
+      case _CharT('%'):
+        __parse_conversion_spec(__begin, __end, __flags);
+        [[fallthrough]];
+
+      default:
+        // All other literals
+        ++__begin;
+      }
+
+    } while (__begin != __end && *__begin != _CharT('}'));
+
+    return __begin;
+  }
+
+  /// \pre *__begin == '%'
+  /// \post __begin points at the end parsed conversion-spec
+  _LIBCPP_HIDE_FROM_ABI constexpr void
+  __parse_conversion_spec(const _CharT*& __begin, const _CharT* __end, __flags __flags) {
+    ++__begin;
+    if (__begin == __end)
+      std::__throw_format_error("End of input while parsing the modifier chrono conversion-spec");
+
+    switch (*__begin) {
+    case _CharT('n'):
+    case _CharT('t'):
+    case _CharT('%'):
+      break;
+
+    case _CharT('S'):
+      __format_spec::__validate_second(__flags);
+      break;
+
+    case _CharT('M'):
+      __format_spec::__validate_minute(__flags);
+      break;
+
+    case _CharT('p'): // TODO FMT does the formater require an hour or a time?
+    case _CharT('H'):
+    case _CharT('I'):
+      __validate_hour(__flags);
+      break;
+
+    case _CharT('r'):
+    case _CharT('R'):
+    case _CharT('T'):
+    case _CharT('X'):
+      __format_spec::__validate_time(__flags);
+      break;
+
+    case _CharT('d'):
+    case _CharT('e'):
+      __format_spec::__validate_day(__flags);
+      break;
+
+    case _CharT('b'):
+    case _CharT('h'):
+    case _CharT('B'):
+      __parser_.__month_name_ = true;
+      [[fallthrough]];
+    case _CharT('m'):
+      __format_spec::__validate_month(__flags);
+      break;
+
+    case _CharT('y'):
+    case _CharT('C'):
+    case _CharT('Y'):
+      __format_spec::__validate_year(__flags);
+      break;
+
+    case _CharT('j'):
+      __parser_.__day_of_year_ = true;
+      __format_spec::__validate_date_or_duration(__flags);
+      break;
+
+    case _CharT('g'):
+    case _CharT('G'):
+    case _CharT('U'):
+    case _CharT('V'):
+    case _CharT('W'):
+      __parser_.__week_of_year_ = true;
+      [[fallthrough]];
+    case _CharT('x'):
+    case _CharT('D'):
+    case _CharT('F'):
+      __format_spec::__validate_date(__flags);
+      break;
+
+    case _CharT('c'):
+      __format_spec::__validate_date_time(__flags);
+      break;
+
+    case _CharT('a'):
+    case _CharT('A'):
+      __parser_.__weekday_name_ = true;
+      [[fallthrough]];
+    case _CharT('u'):
+    case _CharT('w'):
+      __parser_.__weekday_ = true;
+      __validate_weekday(__flags);
+      __format_spec::__validate_weekday(__flags);
+      break;
+
+    case _CharT('q'):
+    case _CharT('Q'):
+      __format_spec::__validate_duration(__flags);
+      break;
+
+    case _CharT('E'):
+      __parse_modifier_E(__begin, __end, __flags);
+      break;
+
+    case _CharT('O'):
+      __parse_modifier_O(__begin, __end, __flags);
+      break;
+
+    case _CharT('z'):
+    case _CharT('Z'):
+      // Currently there's no time zone information. However some clocks have a
+      // hard-coded "time zone", for these clocks the information can be used.
+      // TODO FMT implement time zones.
+      __format_spec::__validate_time_zone(__flags);
+      break;
+
+    default: // unknown type;
+      std::__throw_format_error("The date time type specifier is invalid");
+    }
+  }
+
+  /// \pre *__begin == 'E'
+  /// \post __begin is incremented by one.
+  _LIBCPP_HIDE_FROM_ABI constexpr void
+  __parse_modifier_E(const _CharT*& __begin, const _CharT* __end, __flags __flags) {
+    ++__begin;
+    if (__begin == __end)
+      std::__throw_format_error("End of input while parsing the modifier E");
+
+    switch (*__begin) {
+    case _CharT('X'):
+      __format_spec::__validate_time(__flags);
+      break;
+
+    case _CharT('y'):
+    case _CharT('C'):
+    case _CharT('Y'):
+      __format_spec::__validate_year(__flags);
+      break;
+
+    case _CharT('x'):
+      __format_spec::__validate_date(__flags);
+      break;
+
+    case _CharT('c'):
+      __format_spec::__validate_date_time(__flags);
+      break;
+
+    case _CharT('z'):
+      // Currently there's no time zone information. However some clocks have a
+      // hard-coded "time zone", for these clocks the information can be used.
+      // TODO FMT implement time zones.
+      __format_spec::__validate_time_zone(__flags);
+      break;
+
+    default:
+      std::__throw_format_error("The date time type specifier for modifier E is invalid");
+    }
+  }
+
+  /// \pre *__begin == 'O'
+  /// \post __begin is incremented by one.
+  _LIBCPP_HIDE_FROM_ABI constexpr void
+  __parse_modifier_O(const _CharT*& __begin, const _CharT* __end, __flags __flags) {
+    ++__begin;
+    if (__begin == __end)
+      std::__throw_format_error("End of input while parsing the modifier O");
+
+    switch (*__begin) {
+    case _CharT('S'):
+      __format_spec::__validate_second(__flags);
+      break;
+
+    case _CharT('M'):
+      __format_spec::__validate_minute(__flags);
+      break;
+
+    case _CharT('I'):
+    case _CharT('H'):
+      __format_spec::__validate_hour(__flags);
+      break;
+
+    case _CharT('d'):
+    case _CharT('e'):
+      __format_spec::__validate_day(__flags);
+      break;
+
+    case _CharT('m'):
+      __format_spec::__validate_month(__flags);
+      break;
+
+    case _CharT('y'):
+      __format_spec::__validate_year(__flags);
+      break;
+
+    case _CharT('U'):
+    case _CharT('V'):
+    case _CharT('W'):
+      __parser_.__week_of_year_ = true;
+      __format_spec::__validate_date(__flags);
+      break;
+
+    case _CharT('u'):
+    case _CharT('w'):
+      __parser_.__weekday_ = true;
+      __format_spec::__validate_weekday(__flags);
+      break;
+
+    case _CharT('z'):
+      // Currently there's no time zone information. However some clocks have a
+      // hard-coded "time zone", for these clocks the information can be used.
+      // TODO FMT implement time zones.
+      __format_spec::__validate_time_zone(__flags);
+      break;
+
+    default:
+      std::__throw_format_error("The date time type specifier for modifier O is invalid");
+    }
+  }
+};
+
+} // namespace __format_spec
+
+#endif //_LIBCPP_STD_VER > 17 && !defined(_LIBCPP_HAS_NO_INCOMPLETE_FORMAT)
+
+_LIBCPP_END_NAMESPACE_STD
+
+#endif // _LIBCPP___CHRONO_PARSER_STD_FORMAT_SPEC_H