include/__format/range_formatter.h - llvm-project/libcxx - Git at Google

 // -*- 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
	// -- 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