// -*- 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___FORMAT_RANGE_FORMATTER_H
#define _LIBCPP___FORMAT_RANGE_FORMATTER_H
#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
# pragma GCC system_header
#endif
#include <__algorithm/ranges_copy.h>
#include <__chrono/statically_widen.h>
#include <__concepts/same_as.h>
#include <__config>
#include <__format/buffer.h>
#include <__format/concepts.h>
#include <__format/format_context.h>
#include <__format/format_error.h>
#include <__format/formatter.h>
#include <__format/formatter_output.h>
#include <__format/parser_std_format_spec.h>
#include <__iterator/back_insert_iterator.h>
#include <__ranges/concepts.h>
#include <__ranges/data.h>
#include <__ranges/from_range.h>
#include <__ranges/size.h>
#include <__type_traits/remove_cvref.h>
#include <string_view>
_LIBCPP_BEGIN_NAMESPACE_STD
#if _LIBCPP_STD_VER >= 23
template <class _Tp, class _CharT = char>
requires same_as<remove_cvref_t<_Tp>, _Tp> && formattable<_Tp, _CharT>
struct _LIBCPP_TEMPLATE_VIS range_formatter {
_LIBCPP_HIDE_FROM_ABI constexpr void set_separator(basic_string_view<_CharT> __separator) noexcept {
__separator_ = __separator;
}
_LIBCPP_HIDE_FROM_ABI constexpr void
set_brackets(basic_string_view<_CharT> __opening_bracket, basic_string_view<_CharT> __closing_bracket) noexcept {
__opening_bracket_ = __opening_bracket;
__closing_bracket_ = __closing_bracket;
}
_LIBCPP_HIDE_FROM_ABI constexpr formatter<_Tp, _CharT>& underlying() noexcept { return __underlying_; }
_LIBCPP_HIDE_FROM_ABI constexpr const formatter<_Tp, _CharT>& underlying() const noexcept { return __underlying_; }
template <class _ParseContext>
_LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
auto __begin = __parser_.__parse(__ctx, __format_spec::__fields_range);
auto __end = __ctx.end();
// Note the cases where __begin == __end in this code only happens when the
// replacement-field has no terminating }, or when the parse is manually
// called with a format-spec. The former is an error and the latter means
// using a formatter without the format functions or print.
if (__begin == __end) [[unlikely]]
return __parse_empty_range_underlying_spec(__ctx, __begin);
// The n field overrides a possible m type, therefore delay applying the
// effect of n until the type has been procesed.
__parse_type(__begin, __end);
if (__parser_.__clear_brackets_)
set_brackets({}, {});
if (__begin == __end) [[unlikely]]
return __parse_empty_range_underlying_spec(__ctx, __begin);
bool __has_range_underlying_spec = *__begin == _CharT(':');
if (__has_range_underlying_spec) {
// range-underlying-spec:
// : format-spec
++__begin;
} else if (__begin != __end && *__begin != _CharT('}'))
// When there is no underlaying range the current parse should have
// consumed the format-spec. If not, the not consumed input will be
// processed by the underlying. For example {:-} for a range in invalid,
// the sign field is not present. Without this check the underlying_ will
// get -} as input which my be valid.
std::__throw_format_error("The format specifier should consume the input or end with a '}'");
__ctx.advance_to(__begin);
__begin = __underlying_.parse(__ctx);
// This test should not be required if __has_range_underlying_spec is false.
// However this test makes sure the underlying formatter left the parser in
// a valid state. (Note this is not a full protection against evil parsers.
// For example
// } this is test for the next argument {}
// ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^
// could consume more than it should.
if (__begin != __end && *__begin != _CharT('}'))
std::__throw_format_error("The format specifier should consume the input or end with a '}'");
if (__parser_.__type_ != __format_spec::__type::__default) {
// [format.range.formatter]/6
// If the range-type is s or ?s, then there shall be no n option and no
// range-underlying-spec.
if (__parser_.__clear_brackets_) {
if (__parser_.__type_ == __format_spec::__type::__string)
std::__throw_format_error("The n option and type s can't be used together");
std::__throw_format_error("The n option and type ?s can't be used together");
}
if (__has_range_underlying_spec) {
if (__parser_.__type_ == __format_spec::__type::__string)
std::__throw_format_error("Type s and an underlying format specification can't be used together");
std::__throw_format_error("Type ?s and an underlying format specification can't be used together");
}
} else if (!__has_range_underlying_spec)
std::__set_debug_format(__underlying_);
return __begin;
}
template <ranges::input_range _Rp, class _FormatContext>
requires formattable<ranges::range_reference_t<_Rp>, _CharT> &&
same_as<remove_cvref_t<ranges::range_reference_t<_Rp>>, _Tp>
_LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator format(_Rp&& __range, _FormatContext& __ctx) const {
__format_spec::__parsed_specifications<_CharT> __specs = __parser_.__get_parsed_std_specifications(__ctx);
if (!__specs.__has_width())
return __format_range(__range, __ctx, __specs);
// The size of the buffer needed is:
// - open bracket characters
// - close bracket character
// - n elements where every element may have a different size
// - (n -1) separators
// The size of the element is hard to predict, knowing the type helps but
// it depends on the format-spec. As an initial estimate we guess 6
// characters.
// Typically both brackets are 1 character and the separator is 2
// characters. Which means there will be
// (n - 1) * 2 + 1 + 1 = n * 2 character
// So estimate 8 times the range size as buffer.
std::size_t __capacity_hint = 0;
if constexpr (std::ranges::sized_range<_Rp>)
__capacity_hint = 8 * ranges::size(__range);
__format::__retarget_buffer<_CharT> __buffer{__capacity_hint};
basic_format_context<typename __format::__retarget_buffer<_CharT>::__iterator, _CharT> __c{
__buffer.__make_output_iterator(), __ctx};
__format_range(__range, __c, __specs);
return __formatter::__write_string_no_precision(__buffer.__view(), __ctx.out(), __specs);
}
template <ranges::input_range _Rp, class _FormatContext>
typename _FormatContext::iterator _LIBCPP_HIDE_FROM_ABI
__format_range(_Rp&& __range, _FormatContext& __ctx, __format_spec::__parsed_specifications<_CharT> __specs) const {
if constexpr (same_as<_Tp, _CharT>) {
switch (__specs.__std_.__type_) {
case __format_spec::__type::__string:
case __format_spec::__type::__debug:
return __format_as_string(__range, __ctx, __specs.__std_.__type_ == __format_spec::__type::__debug);
default:
return __format_as_sequence(__range, __ctx);
}
} else
return __format_as_sequence(__range, __ctx);
}
template <ranges::input_range _Rp, class _FormatContext>
_LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
__format_as_string(_Rp&& __range, _FormatContext& __ctx, bool __debug_format) const {
// When the range is contiguous use a basic_string_view instead to avoid a
// copy of the underlying data. The basic_string_view formatter
// specialization is the "basic" string formatter in libc++.
if constexpr (ranges::contiguous_range<_Rp> && std::ranges::sized_range<_Rp>) {
std::formatter<basic_string_view<_CharT>, _CharT> __formatter;
if (__debug_format)
__formatter.set_debug_format();
return __formatter.format(
basic_string_view<_CharT>{
ranges::data(__range),
ranges::size(__range),
},
__ctx);
} else {
std::formatter<basic_string<_CharT>, _CharT> __formatter;
if (__debug_format)
__formatter.set_debug_format();
return __formatter.format(basic_string<_CharT>{from_range, __range}, __ctx);
}
}
template <ranges::input_range _Rp, class _FormatContext>
_LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
__format_as_sequence(_Rp&& __range, _FormatContext& __ctx) const {
__ctx.advance_to(ranges::copy(__opening_bracket_, __ctx.out()).out);
bool __use_separator = false;
for (auto&& __e : __range) {
if (__use_separator)
__ctx.advance_to(ranges::copy(__separator_, __ctx.out()).out);
else
__use_separator = true;
__ctx.advance_to(__underlying_.format(__e, __ctx));
}
return ranges::copy(__closing_bracket_, __ctx.out()).out;
}
__format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__left};
private:
template <contiguous_iterator _Iterator>
_LIBCPP_HIDE_FROM_ABI constexpr void __parse_type(_Iterator& __begin, _Iterator __end) {
switch (*__begin) {
case _CharT('m'):
if constexpr (__fmt_pair_like<_Tp>) {
set_brackets(_LIBCPP_STATICALLY_WIDEN(_CharT, "{"), _LIBCPP_STATICALLY_WIDEN(_CharT, "}"));
set_separator(_LIBCPP_STATICALLY_WIDEN(_CharT, ", "));
++__begin;
} else
std::__throw_format_error("Type m requires a pair or a tuple with two elements");
break;
case _CharT('s'):
if constexpr (same_as<_Tp, _CharT>) {
__parser_.__type_ = __format_spec::__type::__string;
++__begin;
} else
std::__throw_format_error("Type s requires character type as formatting argument");
break;
case _CharT('?'):
++__begin;
if (__begin == __end || *__begin != _CharT('s'))
std::__throw_format_error("The format specifier should consume the input or end with a '}'");
if constexpr (same_as<_Tp, _CharT>) {
__parser_.__type_ = __format_spec::__type::__debug;
++__begin;
} else
std::__throw_format_error("Type ?s requires character type as formatting argument");
}
}
template <class _ParseContext>
_LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator
__parse_empty_range_underlying_spec(_ParseContext& __ctx, typename _ParseContext::iterator __begin) {
__ctx.advance_to(__begin);
[[maybe_unused]] typename _ParseContext::iterator __result = __underlying_.parse(__ctx);
_LIBCPP_ASSERT_INTERNAL(__result == __begin,
"the underlying's parse function should not advance the input beyond the end of the input");
return __begin;
}
formatter<_Tp, _CharT> __underlying_;
basic_string_view<_CharT> __separator_ = _LIBCPP_STATICALLY_WIDEN(_CharT, ", ");
basic_string_view<_CharT> __opening_bracket_ = _LIBCPP_STATICALLY_WIDEN(_CharT, "[");
basic_string_view<_CharT> __closing_bracket_ = _LIBCPP_STATICALLY_WIDEN(_CharT, "]");
};
#endif // _LIBCPP_STD_VER >= 23
_LIBCPP_END_NAMESPACE_STD
#endif // _LIBCPP___FORMAT_RANGE_FORMATTER_H
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