include/__format/write_escaped.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_WRITE_ESCAPED_H
 #define _LIBCPP___FORMAT_WRITE_ESCAPED_H

 #include <__algorithm/ranges_copy.h>
 #include <__algorithm/ranges_for_each.h>
 #include <__charconv/to_chars_integral.h>
 #include <__charconv/to_chars_result.h>
 #include <__chrono/statically_widen.h>
 #include <__format/escaped_output_table.h>
 #include <__format/formatter_output.h>
 #include <__format/parser_std_format_spec.h>
 #include <__format/unicode.h>
 #include <__iterator/back_insert_iterator.h>
 #include <__memory/addressof.h>
 #include <__system_error/errc.h>
 #include <__type_traits/make_unsigned.h>
 #include <__utility/move.h>
 #include <string_view>

 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
 #  pragma GCC system_header
 #endif

 _LIBCPP_PUSH_MACROS
 #include <__undef_macros>

 _LIBCPP_BEGIN_NAMESPACE_STD

 namespace __formatter {

 #if _LIBCPP_STD_VER >= 20

 /// Writes a string using format's width estimation algorithm.
 ///
 /// \note When \c _LIBCPP_HAS_NO_UNICODE is defined the function assumes the
 /// input is ASCII.
 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI auto
 __write_string(basic_string_view<_CharT> __str,
                output_iterator<const _CharT&> auto __out_it,
                __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) {
   if (!__specs.__has_precision())
     return __formatter::__write_string_no_precision(__str, std::move(__out_it), __specs);

   int __size = __formatter::__truncate(__str, __specs.__precision_);

   return __formatter::__write(__str.begin(), __str.end(), std::move(__out_it), __specs, __size);
 }

 #endif // _LIBCPP_STD_VER >= 20
 #if _LIBCPP_STD_VER >= 23

 struct __nul_terminator {};

 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI bool operator==(const _CharT* __cstr, __nul_terminator) {
   return *__cstr == _CharT('\0');
 }

 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI void
 __write_escaped_code_unit(basic_string<_CharT>& __str, char32_t __value, const _CharT* __prefix) {
   back_insert_iterator __out_it{__str};
   std::ranges::copy(__prefix, __nul_terminator{}, __out_it);

   char __buffer[8];
   to_chars_result __r = std::to_chars(std::begin(__buffer), std::end(__buffer), __value, 16);
   _LIBCPP_ASSERT_INTERNAL(__r.ec == errc(0), "Internal buffer too small");
   std::ranges::copy(std::begin(__buffer), __r.ptr, __out_it);

   __str += _CharT('}');
 }

 // [format.string.escaped]/2.2.1.2
 // ...
 // then the sequence \u{hex-digit-sequence} is appended to E, where
 // hex-digit-sequence is the shortest hexadecimal representation of C using
 // lower-case hexadecimal digits.
 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI void __write_well_formed_escaped_code_unit(basic_string<_CharT>& __str, char32_t __value) {
   __formatter::__write_escaped_code_unit(__str, __value, _LIBCPP_STATICALLY_WIDEN(_CharT, "\\u{"));
 }

 // [format.string.escaped]/2.2.3
 // Otherwise (X is a sequence of ill-formed code units), each code unit U is
 // appended to E in order as the sequence \x{hex-digit-sequence}, where
 // hex-digit-sequence is the shortest hexadecimal representation of U using
 // lower-case hexadecimal digits.
 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI void __write_escape_ill_formed_code_unit(basic_string<_CharT>& __str, char32_t __value) {
   __formatter::__write_escaped_code_unit(__str, __value, _LIBCPP_STATICALLY_WIDEN(_CharT, "\\x{"));
 }

 template <class _CharT>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool
 __is_escaped_sequence_written(basic_string<_CharT>& __str, bool __last_escaped, char32_t __value) {
 #  ifdef _LIBCPP_HAS_NO_UNICODE
   // For ASCII assume everything above 127 is printable.
   if (__value > 127)
     return false;
 #  endif

   // [format.string.escaped]/2.2.1.2.1
   //   CE is UTF-8, UTF-16, or UTF-32 and C corresponds to a Unicode scalar
   //   value whose Unicode property General_Category has a value in the groups
   //   Separator (Z) or Other (C), as described by UAX #44 of the Unicode Standard,
   if (!__escaped_output_table::__needs_escape(__value))
     // [format.string.escaped]/2.2.1.2.2
     //   CE is UTF-8, UTF-16, or UTF-32 and C corresponds to a Unicode scalar
     //   value with the Unicode property Grapheme_Extend=Yes as described by UAX
     //   #44 of the Unicode Standard and C is not immediately preceded in S by a
     //   character P appended to E without translation to an escape sequence,
     if (!__last_escaped || __extended_grapheme_custer_property_boundary::__get_property(__value) !=
                                __extended_grapheme_custer_property_boundary::__property::__Extend)
       return false;

   __formatter::__write_well_formed_escaped_code_unit(__str, __value);
   return true;
 }

 template <class _CharT>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr char32_t __to_char32(_CharT __value) {
   return static_cast<make_unsigned_t<_CharT>>(__value);
 }

 enum class __escape_quotation_mark { __apostrophe, __double_quote };

 // [format.string.escaped]/2
 template <class _CharT>
 [[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool __is_escaped_sequence_written(
     basic_string<_CharT>& __str, char32_t __value, bool __last_escaped, __escape_quotation_mark __mark) {
   // 2.2.1.1 - Mapped character in [tab:format.escape.sequences]
   switch (__value) {
   case _CharT('\t'):
     __str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\t");
     return true;
   case _CharT('\n'):
     __str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\n");
     return true;
   case _CharT('\r'):
     __str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\r");
     return true;
   case _CharT('\''):
     if (__mark == __escape_quotation_mark::__apostrophe)
       __str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\')");
     else
       __str += __value;
     return true;
   case _CharT('"'):
     if (__mark == __escape_quotation_mark::__double_quote)
       __str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\")");
     else
       __str += __value;
     return true;
   case _CharT('\\'):
     __str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\\)");
     return true;

   // 2.2.1.2 - Space
   case _CharT(' '):
     __str += __value;
     return true;
   }

   // 2.2.2
   //   Otherwise, if X is a shift sequence, the effect on E and further
   //   decoding of S is unspecified.
   // For now shift sequences are ignored and treated as Unicode. Other parts
   // of the format library do the same. It's unknown how ostream treats them.
   // TODO FMT determine what to do with shift sequences.

   // 2.2.1.2.1 and 2.2.1.2.2 - Escape
   return __formatter::__is_escaped_sequence_written(__str, __last_escaped, __formatter::__to_char32(__value));
 }

 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI void
 __escape(basic_string<_CharT>& __str, basic_string_view<_CharT> __values, __escape_quotation_mark __mark) {
   __unicode::__code_point_view<_CharT> __view{__values.begin(), __values.end()};

   // When the first code unit has the property Grapheme_Extend=Yes it needs to
   // be escaped. This happens when the previous code unit was also escaped.
   bool __escape = true;
   while (!__view.__at_end()) {
     auto __first                                  = __view.__position();
     typename __unicode::__consume_result __result = __view.__consume();
     if (__result.__status == __unicode::__consume_result::__ok) {
       __escape = __formatter::__is_escaped_sequence_written(__str, __result.__code_point, __escape, __mark);
       if (!__escape)
         // 2.2.1.3 - Add the character
         ranges::copy(__first, __view.__position(), std::back_insert_iterator(__str));
     } else {
       // 2.2.3 sequence of ill-formed code units
       ranges::for_each(__first, __view.__position(), [&](_CharT __value) {
         __formatter::__write_escape_ill_formed_code_unit(__str, __formatter::__to_char32(__value));
       });
     }
   }
 }

 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI auto
 __format_escaped_char(_CharT __value,
                       output_iterator<const _CharT&> auto __out_it,
                       __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) {
   basic_string<_CharT> __str;
   __str += _CharT('\'');
   __formatter::__escape(__str, basic_string_view{std::addressof(__value), 1}, __escape_quotation_mark::__apostrophe);
   __str += _CharT('\'');
   return __formatter::__write(__str.data(), __str.data() + __str.size(), std::move(__out_it), __specs, __str.size());
 }

 template <class _CharT>
 _LIBCPP_HIDE_FROM_ABI auto
 __format_escaped_string(basic_string_view<_CharT> __values,
                         output_iterator<const _CharT&> auto __out_it,
                         __format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) {
   basic_string<_CharT> __str;
   __str += _CharT('"');
   __formatter::__escape(__str, __values, __escape_quotation_mark::__double_quote);
   __str += _CharT('"');
   return __formatter::__write_string(basic_string_view{__str}, std::move(__out_it), __specs);
 }

 #endif // _LIBCPP_STD_VER >= 23

 } // namespace __formatter

 _LIBCPP_END_NAMESPACE_STD

 _LIBCPP_POP_MACROS

 #endif // _LIBCPP___FORMAT_WRITE_ESCAPED_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_WRITE_ESCAPED_H
	#define _LIBCPP___FORMAT_WRITE_ESCAPED_H

	#include <__algorithm/ranges_copy.h>
	#include <__algorithm/ranges_for_each.h>
	#include <__charconv/to_chars_integral.h>
	#include <__charconv/to_chars_result.h>
	#include <__chrono/statically_widen.h>
	#include <__format/escaped_output_table.h>
	#include <__format/formatter_output.h>
	#include <__format/parser_std_format_spec.h>
	#include <__format/unicode.h>
	#include <__iterator/back_insert_iterator.h>
	#include <__memory/addressof.h>
	#include <__system_error/errc.h>
	#include <__type_traits/make_unsigned.h>
	#include <__utility/move.h>
	#include <string_view>

	#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
	# pragma GCC system_header
	#endif

	_LIBCPP_PUSH_MACROS
	#include <__undef_macros>

	_LIBCPP_BEGIN_NAMESPACE_STD

	namespace __formatter {

	#if _LIBCPP_STD_VER >= 20

	/// Writes a string using format's width estimation algorithm.
	///
	/// \note When \c _LIBCPP_HAS_NO_UNICODE is defined the function assumes the
	/// input is ASCII.
	template <class _CharT>
	_LIBCPP_HIDE_FROM_ABI auto
	__write_string(basic_string_view<_CharT> __str,
	output_iterator<const _CharT&> auto __out_it,
	__format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) {
	if (!__specs.__has_precision())
	return __formatter::__write_string_no_precision(__str, std::move(__out_it), __specs);

	int __size = __formatter::__truncate(__str, __specs.__precision_);

	return __formatter::__write(__str.begin(), __str.end(), std::move(__out_it), __specs, __size);
	}

	#endif // _LIBCPP_STD_VER >= 20
	#if _LIBCPP_STD_VER >= 23

	struct __nul_terminator {};

	template <class _CharT>
	_LIBCPP_HIDE_FROM_ABI bool operator==(const _CharT* __cstr, __nul_terminator) {
	return *__cstr == _CharT('\0');
	}

	template <class _CharT>
	_LIBCPP_HIDE_FROM_ABI void
	__write_escaped_code_unit(basic_string<_CharT>& __str, char32_t __value, const _CharT* __prefix) {
	back_insert_iterator __out_it{__str};
	std::ranges::copy(__prefix, __nul_terminator{}, __out_it);

	char __buffer[8];
	to_chars_result __r = std::to_chars(std::begin(__buffer), std::end(__buffer), __value, 16);
	_LIBCPP_ASSERT_INTERNAL(__r.ec == errc(0), "Internal buffer too small");
	std::ranges::copy(std::begin(__buffer), __r.ptr, __out_it);

	__str += _CharT('}');
	}

	// [format.string.escaped]/2.2.1.2
	// ...
	// then the sequence \u{hex-digit-sequence} is appended to E, where
	// hex-digit-sequence is the shortest hexadecimal representation of C using
	// lower-case hexadecimal digits.
	template <class _CharT>
	_LIBCPP_HIDE_FROM_ABI void __write_well_formed_escaped_code_unit(basic_string<_CharT>& __str, char32_t __value) {
	__formatter::__write_escaped_code_unit(__str, __value, _LIBCPP_STATICALLY_WIDEN(_CharT, "\\u{"));
	}

	// [format.string.escaped]/2.2.3
	// Otherwise (X is a sequence of ill-formed code units), each code unit U is
	// appended to E in order as the sequence \x{hex-digit-sequence}, where
	// hex-digit-sequence is the shortest hexadecimal representation of U using
	// lower-case hexadecimal digits.
	template <class _CharT>
	_LIBCPP_HIDE_FROM_ABI void __write_escape_ill_formed_code_unit(basic_string<_CharT>& __str, char32_t __value) {
	__formatter::__write_escaped_code_unit(__str, __value, _LIBCPP_STATICALLY_WIDEN(_CharT, "\\x{"));
	}

	template <class _CharT>
	[[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool
	__is_escaped_sequence_written(basic_string<_CharT>& __str, bool __last_escaped, char32_t __value) {
	# ifdef _LIBCPP_HAS_NO_UNICODE
	// For ASCII assume everything above 127 is printable.
	if (__value > 127)
	return false;
	# endif

	// [format.string.escaped]/2.2.1.2.1
	// CE is UTF-8, UTF-16, or UTF-32 and C corresponds to a Unicode scalar
	// value whose Unicode property General_Category has a value in the groups
	// Separator (Z) or Other (C), as described by UAX #44 of the Unicode Standard,
	if (!__escaped_output_table::__needs_escape(__value))
	// [format.string.escaped]/2.2.1.2.2
	// CE is UTF-8, UTF-16, or UTF-32 and C corresponds to a Unicode scalar
	// value with the Unicode property Grapheme_Extend=Yes as described by UAX
	// #44 of the Unicode Standard and C is not immediately preceded in S by a
	// character P appended to E without translation to an escape sequence,
	if (!__last_escaped \|\| __extended_grapheme_custer_property_boundary::__get_property(__value) !=
	__extended_grapheme_custer_property_boundary::__property::__Extend)
	return false;

	__formatter::__write_well_formed_escaped_code_unit(__str, __value);
	return true;
	}

	template <class _CharT>
	[[nodiscard]] _LIBCPP_HIDE_FROM_ABI constexpr char32_t __to_char32(_CharT __value) {
	return static_cast<make_unsigned_t<_CharT>>(__value);
	}

	enum class __escape_quotation_mark { __apostrophe, __double_quote };

	// [format.string.escaped]/2
	template <class _CharT>
	[[nodiscard]] _LIBCPP_HIDE_FROM_ABI bool __is_escaped_sequence_written(
	basic_string<_CharT>& __str, char32_t __value, bool __last_escaped, __escape_quotation_mark __mark) {
	// 2.2.1.1 - Mapped character in [tab:format.escape.sequences]
	switch (__value) {
	case _CharT('\t'):
	__str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\t");
	return true;
	case _CharT('\n'):
	__str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\n");
	return true;
	case _CharT('\r'):
	__str += _LIBCPP_STATICALLY_WIDEN(_CharT, "\\r");
	return true;
	case _CharT('\''):
	if (__mark == __escape_quotation_mark::__apostrophe)
	__str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\')");
	else
	__str += __value;
	return true;
	case _CharT('"'):
	if (__mark == __escape_quotation_mark::__double_quote)
	__str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\")");
	else
	__str += __value;
	return true;
	case _CharT('\\'):
	__str += _LIBCPP_STATICALLY_WIDEN(_CharT, R"(\\)");
	return true;

	// 2.2.1.2 - Space
	case _CharT(' '):
	__str += __value;
	return true;
	}

	// 2.2.2
	// Otherwise, if X is a shift sequence, the effect on E and further
	// decoding of S is unspecified.
	// For now shift sequences are ignored and treated as Unicode. Other parts
	// of the format library do the same. It's unknown how ostream treats them.
	// TODO FMT determine what to do with shift sequences.

	// 2.2.1.2.1 and 2.2.1.2.2 - Escape
	return __formatter::__is_escaped_sequence_written(__str, __last_escaped, __formatter::__to_char32(__value));
	}

	template <class _CharT>
	_LIBCPP_HIDE_FROM_ABI void
	__escape(basic_string<_CharT>& __str, basic_string_view<_CharT> __values, __escape_quotation_mark __mark) {
	__unicode::__code_point_view<_CharT> __view{__values.begin(), __values.end()};

	// When the first code unit has the property Grapheme_Extend=Yes it needs to
	// be escaped. This happens when the previous code unit was also escaped.
	bool __escape = true;
	while (!__view.__at_end()) {
	auto __first = __view.__position();
	typename __unicode::__consume_result __result = __view.__consume();
	if (__result.__status == __unicode::__consume_result::__ok) {
	__escape = __formatter::__is_escaped_sequence_written(__str, __result.__code_point, __escape, __mark);
	if (!__escape)
	// 2.2.1.3 - Add the character
	ranges::copy(__first, __view.__position(), std::back_insert_iterator(__str));
	} else {
	// 2.2.3 sequence of ill-formed code units
	ranges::for_each(__first, __view.__position(), [&](_CharT __value) {
	__formatter::__write_escape_ill_formed_code_unit(__str, __formatter::__to_char32(__value));
	});
	}
	}
	}

	template <class _CharT>
	_LIBCPP_HIDE_FROM_ABI auto
	__format_escaped_char(_CharT __value,
	output_iterator<const _CharT&> auto __out_it,
	__format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) {
	basic_string<_CharT> __str;
	__str += _CharT('\'');
	__formatter::__escape(__str, basic_string_view{std::addressof(__value), 1}, __escape_quotation_mark::__apostrophe);
	__str += _CharT('\'');
	return __formatter::__write(__str.data(), __str.data() + __str.size(), std::move(__out_it), __specs, __str.size());
	}

	template <class _CharT>
	_LIBCPP_HIDE_FROM_ABI auto
	__format_escaped_string(basic_string_view<_CharT> __values,
	output_iterator<const _CharT&> auto __out_it,
	__format_spec::__parsed_specifications<_CharT> __specs) -> decltype(__out_it) {
	basic_string<_CharT> __str;
	__str += _CharT('"');
	__formatter::__escape(__str, __values, __escape_quotation_mark::__double_quote);
	__str += _CharT('"');
	return __formatter::__write_string(basic_string_view{__str}, std::move(__out_it), __specs);
	}

	#endif // _LIBCPP_STD_VER >= 23

	} // namespace __formatter

	_LIBCPP_END_NAMESPACE_STD

	_LIBCPP_POP_MACROS

	#endif // _LIBCPP___FORMAT_WRITE_ESCAPED_H