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Diffstat (limited to 'libcxx/include/__format/range_formatter.h')
| -rw-r--r-- | libcxx/include/__format/range_formatter.h | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/libcxx/include/__format/range_formatter.h b/libcxx/include/__format/range_formatter.h new file mode 100644 index 000000000000..9ea61a70350a --- /dev/null +++ b/libcxx/include/__format/range_formatter.h @@ -0,0 +1,255 @@ +// -*- 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 <__availability> +#include <__chrono/statically_widen.h> +#include <__concepts/same_as.h> +#include <__config> +#include <__format/buffer.h> +#include <__format/concepts.h> +#include <__format/format_args.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/size.h> +#include <__type_traits/remove_cvref.h> +#include <string_view> + +_LIBCPP_BEGIN_NAMESPACE_STD + +#if _LIBCPP_STD_VER > 20 + +template <class _Tp, class _CharT = char> + requires same_as<remove_cvref_t<_Tp>, _Tp> && formattable<_Tp, _CharT> +struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT range_formatter { + _LIBCPP_HIDE_FROM_ABI constexpr void set_separator(basic_string_view<_CharT> __separator) { + __separator_ = __separator; + } + _LIBCPP_HIDE_FROM_ABI constexpr void + set_brackets(basic_string_view<_CharT> __opening_bracket, basic_string_view<_CharT> __closing_bracket) { + __opening_bracket_ = __opening_bracket; + __closing_bracket_ = __closing_bracket; + } + + _LIBCPP_HIDE_FROM_ABI constexpr formatter<_Tp, _CharT>& underlying() { return __underlying_; } + _LIBCPP_HIDE_FROM_ABI constexpr const formatter<_Tp, _CharT>& underlying() const { return __underlying_; } + + template <class _ParseContext> + _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __parse_ctx) { + const _CharT* __begin = __parser_.__parse(__parse_ctx, __format_spec::__fields_range); + const _CharT* __end = __parse_ctx.end(); + if (__begin == __end) + return __begin; + + // The n field overrides a possible m type, therefore delay applying the + // effect of n until the type has been procesed. + bool __clear_brackets = (*__begin == _CharT('n')); + if (__clear_brackets) { + ++__begin; + if (__begin == __end) { + // Since there is no more data, clear the brackets before returning. + set_brackets({}, {}); + return __begin; + } + } + + __parse_type(__begin, __end); + if (__clear_brackets) + set_brackets({}, {}); + if (__begin == __end) + return __begin; + + bool __has_range_underlying_spec = *__begin == _CharT(':'); + 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 (__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_); + + if (__has_range_underlying_spec) { + // range-underlying-spec: + // : format-spec + ++__begin; + if (__begin == __end) + return __begin; + + __parse_ctx.advance_to(__begin); + __begin = __underlying_.parse(__parse_ctx); + } + + if (__begin != __end && *__begin != _CharT('}')) + std::__throw_format_error("The format-spec should consume the input or end with a '}'"); + + 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(); + // P2106's from_range has not been implemented yet. Instead use a simple + // copy operation. + // TODO FMT use basic_string's "from_range" constructor. + // return std::formatter<basic_string<_CharT>, _CharT>{}.format(basic_string<_CharT>{from_range, __range}, __ctx); + basic_string<_CharT> __str; + ranges::copy(__range, back_insert_iterator{__str}); + return __formatter.format(__str, __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: + _LIBCPP_HIDE_FROM_ABI constexpr void __parse_type(const _CharT*& __begin, const _CharT* __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("The range-format-spec type m requires two elements for a pair or tuple"); + break; + + case _CharT('s'): + if constexpr (same_as<_Tp, _CharT>) { + __parser_.__type_ = __format_spec::__type::__string; + ++__begin; + } else + std::__throw_format_error("The range-format-spec type s requires formatting a character type"); + break; + + case _CharT('?'): + ++__begin; + if (__begin == __end || *__begin != _CharT('s')) + std::__throw_format_error("The format-spec 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("The range-format-spec type ?s requires formatting a character type"); + } + } + + 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 > 20 + +_LIBCPP_END_NAMESPACE_STD + +#endif // _LIBCPP___FORMAT_RANGE_FORMATTER_H |