1 // -*- C++ -*- 2 //===----------------------------------------------------------------------===// 3 // 4 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 5 // See https://llvm.org/LICENSE.txt for license information. 6 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 7 // 8 //===----------------------------------------------------------------------===// 9 10 #ifndef _LIBCPP___FORMAT_FORMATTER_STRING_H 11 #define _LIBCPP___FORMAT_FORMATTER_STRING_H 12 13 #include <__assert> 14 #include <__config> 15 #include <__format/format_error.h> 16 #include <__format/format_fwd.h> 17 #include <__format/format_string.h> 18 #include <__format/formatter.h> 19 #include <__format/parser_std_format_spec.h> 20 #include <string_view> 21 22 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER) 23 # pragma GCC system_header 24 #endif 25 26 _LIBCPP_BEGIN_NAMESPACE_STD 27 28 #if _LIBCPP_STD_VER > 17 29 30 namespace __format_spec { 31 32 template <__formatter::__char_type _CharT> 33 class _LIBCPP_TEMPLATE_VIS __formatter_string : public __parser_string<_CharT> { 34 public: 35 _LIBCPP_HIDE_FROM_ABI auto format(basic_string_view<_CharT> __str, 36 auto& __ctx) -> decltype(__ctx.out()) { 37 38 _LIBCPP_ASSERT(this->__alignment != _Flags::_Alignment::__default, 39 "The parser should not use these defaults"); 40 41 if (this->__width_needs_substitution()) 42 this->__substitute_width_arg_id(__ctx.arg(this->__width)); 43 44 if (this->__precision_needs_substitution()) 45 this->__substitute_precision_arg_id(__ctx.arg(this->__precision)); 46 47 return __formatter::__write_unicode( 48 __ctx.out(), __str, this->__width, 49 this->__has_precision_field() ? this->__precision : -1, this->__fill, 50 this->__alignment); 51 } 52 }; 53 54 } //namespace __format_spec 55 56 // [format.formatter.spec]/2.2 For each charT, the string type specializations 57 58 // Formatter const char*. 59 template <__formatter::__char_type _CharT> 60 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT 61 formatter<const _CharT*, _CharT> 62 : public __format_spec::__formatter_string<_CharT> { 63 using _Base = __format_spec::__formatter_string<_CharT>; 64 65 _LIBCPP_HIDE_FROM_ABI auto format(const _CharT* __str, auto& __ctx) 66 -> decltype(__ctx.out()) { 67 _LIBCPP_ASSERT(__str, "The basic_format_arg constructor should have " 68 "prevented an invalid pointer."); 69 70 // When using a center or right alignment and the width option the length 71 // of __str must be known to add the padding upfront. This case is handled 72 // by the base class by converting the argument to a basic_string_view. 73 // 74 // When using left alignment and the width option the padding is added 75 // after outputting __str so the length can be determined while outputting 76 // __str. The same holds true for the precision, during outputting __str it 77 // can be validated whether the precision threshold has been reached. For 78 // now these optimizations aren't implemented. Instead the base class 79 // handles these options. 80 // TODO FMT Implement these improvements. 81 if (this->__has_width_field() || this->__has_precision_field()) 82 return _Base::format(__str, __ctx); 83 84 // No formatting required, copy the string to the output. 85 auto __out_it = __ctx.out(); 86 while (*__str) 87 *__out_it++ = *__str++; 88 return __out_it; 89 } 90 }; 91 92 // Formatter char*. 93 template <__formatter::__char_type _CharT> 94 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT 95 formatter<_CharT*, _CharT> : public formatter<const _CharT*, _CharT> { 96 using _Base = formatter<const _CharT*, _CharT>; 97 98 _LIBCPP_HIDE_FROM_ABI auto format(_CharT* __str, auto& __ctx) 99 -> decltype(__ctx.out()) { 100 return _Base::format(__str, __ctx); 101 } 102 }; 103 104 // Formatter char[]. 105 template <__formatter::__char_type _CharT, size_t _Size> 106 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<_CharT[_Size], _CharT> 107 : public __format_spec::__formatter_string<_CharT> { 108 static_assert(!is_const_v<_CharT>); 109 using _Base = __format_spec::__formatter_string<_CharT>; 110 111 _LIBCPP_HIDE_FROM_ABI auto format(_CharT __str[_Size], auto& __ctx) -> decltype(__ctx.out()) { 112 return _Base::format(basic_string_view<_CharT>(__str, _Size), __ctx); 113 } 114 }; 115 116 // Formatter const char[]. 117 template <__formatter::__char_type _CharT, size_t _Size> 118 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT 119 formatter<const _CharT[_Size], _CharT> 120 : public __format_spec::__formatter_string<_CharT> { 121 using _Base = __format_spec::__formatter_string<_CharT>; 122 123 _LIBCPP_HIDE_FROM_ABI auto format(const _CharT __str[_Size], auto& __ctx) 124 -> decltype(__ctx.out()) { 125 return _Base::format(basic_string_view<_CharT>(__str, _Size), __ctx); 126 } 127 }; 128 129 // Formatter std::string. 130 template <__formatter::__char_type _CharT, class _Traits, class _Allocator> 131 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT 132 formatter<basic_string<_CharT, _Traits, _Allocator>, _CharT> 133 : public __format_spec::__formatter_string<_CharT> { 134 using _Base = __format_spec::__formatter_string<_CharT>; 135 136 _LIBCPP_HIDE_FROM_ABI auto 137 format(const basic_string<_CharT, _Traits, _Allocator>& __str, auto& __ctx) 138 -> decltype(__ctx.out()) { 139 // drop _Traits and _Allocator 140 return _Base::format(basic_string_view<_CharT>(__str.data(), __str.size()), __ctx); 141 } 142 }; 143 144 // Formatter std::string_view. 145 template <__formatter::__char_type _CharT, class _Traits> 146 struct _LIBCPP_TEMPLATE_VIS _LIBCPP_AVAILABILITY_FORMAT formatter<basic_string_view<_CharT, _Traits>, _CharT> 147 : public __format_spec::__formatter_string<_CharT> { 148 using _Base = __format_spec::__formatter_string<_CharT>; 149 150 _LIBCPP_HIDE_FROM_ABI auto 151 format(basic_string_view<_CharT, _Traits> __str, auto& __ctx) 152 -> decltype(__ctx.out()) { 153 // drop _Traits 154 return _Base::format(basic_string_view<_CharT>(__str.data(), __str.size()), __ctx); 155 } 156 }; 157 158 #endif //_LIBCPP_STD_VER > 17 159 160 _LIBCPP_END_NAMESPACE_STD 161 162 #endif // _LIBCPP___FORMAT_FORMATTER_STRING_H 163