libcxx/include/__format/formatter_string.h

   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 <__availability>
  14 #include <__config>
  15 #include <__format/concepts.h>
  16 #include <__format/format_parse_context.h>
  17 #include <__format/formatter.h>
  18 #include <__format/formatter_output.h>
  19 #include <__format/parser_std_format_spec.h>
  20 #include <__format/write_escaped.h>
  21 #include <string>
  22 #include <string_view>
  23
  24 #if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
  25 #  pragma GCC system_header
  26 #endif
  27
  28 _LIBCPP_BEGIN_NAMESPACE_STD
  29
  30 #if _LIBCPP_STD_VER >= 20
  31
  32 template <__fmt_char_type _CharT>
  33 struct _LIBCPP_TEMPLATE_VIS __formatter_string {
  34 public:
  35   template <class _ParseContext>
  36   _LIBCPP_HIDE_FROM_ABI constexpr typename _ParseContext::iterator parse(_ParseContext& __ctx) {
  37     typename _ParseContext::iterator __result = __parser_.__parse(__ctx, __format_spec::__fields_string);
  38     __format_spec::__process_display_type_string(__parser_.__type_);
  39     return __result;
  40   }
  41
  42   template <class _FormatContext>
  43   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
  44   format(basic_string_view<_CharT> __str, _FormatContext& __ctx) const {
  45 #  if _LIBCPP_STD_VER >= 23
  46     if (__parser_.__type_ == __format_spec::__type::__debug)
  47       return __formatter::__format_escaped_string(__str, __ctx.out(), __parser_.__get_parsed_std_specifications(__ctx));
  48 #  endif
  49
  50     return __formatter::__write_string(__str, __ctx.out(), __parser_.__get_parsed_std_specifications(__ctx));
  51   }
  52
  53 #  if _LIBCPP_STD_VER >= 23
  54   _LIBCPP_HIDE_FROM_ABI constexpr void set_debug_format() { __parser_.__type_ = __format_spec::__type::__debug; }
  55 #  endif
  56
  57   __format_spec::__parser<_CharT> __parser_{.__alignment_ = __format_spec::__alignment::__left};
  58 };
  59
  60 // Formatter const char*.
  61 template <__fmt_char_type _CharT>
  62 struct _LIBCPP_TEMPLATE_VIS formatter<const _CharT*, _CharT>
  63     : public __formatter_string<_CharT> {
  64   using _Base = __formatter_string<_CharT>;
  65
  66   template <class _FormatContext>
  67   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator format(const _CharT* __str, _FormatContext& __ctx) const {
  68     _LIBCPP_ASSERT_UNCATEGORIZED(__str, "The basic_format_arg constructor should have "
  69                                  "prevented an invalid pointer.");
  70
  71     __format_spec::__parsed_specifications<_CharT> __specs = _Base::__parser_.__get_parsed_std_specifications(__ctx);
  72 #  if _LIBCPP_STD_VER >= 23
  73     if (_Base::__parser_.__type_ == __format_spec::__type::__debug)
  74       return __formatter::__format_escaped_string(basic_string_view<_CharT>{__str}, __ctx.out(), __specs);
  75 #  endif
  76
  77     // When using a center or right alignment and the width option the length
  78     // of __str must be known to add the padding upfront. This case is handled
  79     // by the base class by converting the argument to a basic_string_view.
  80     //
  81     // When using left alignment and the width option the padding is added
  82     // after outputting __str so the length can be determined while outputting
  83     // __str. The same holds true for the precision, during outputting __str it
  84     // can be validated whether the precision threshold has been reached. For
  85     // now these optimizations aren't implemented. Instead the base class
  86     // handles these options.
  87     // TODO FMT Implement these improvements.
  88     if (__specs.__has_width() || __specs.__has_precision())
  89       return __formatter::__write_string(basic_string_view<_CharT>{__str}, __ctx.out(), __specs);
  90
  91     // No formatting required, copy the string to the output.
  92     auto __out_it = __ctx.out();
  93     while (*__str)
  94       *__out_it++ = *__str++;
  95     return __out_it;
  96   }
  97 };
  98
  99 // Formatter char*.
 100 template <__fmt_char_type _CharT>
 101 struct _LIBCPP_TEMPLATE_VIS formatter<_CharT*, _CharT>
 102     : public formatter<const _CharT*, _CharT> {
 103   using _Base = formatter<const _CharT*, _CharT>;
 104
 105   template <class _FormatContext>
 106   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator format(_CharT* __str, _FormatContext& __ctx) const {
 107     return _Base::format(__str, __ctx);
 108   }
 109 };
 110
 111 // Formatter char[].
 112 template <__fmt_char_type _CharT, size_t _Size>
 113 struct _LIBCPP_TEMPLATE_VIS formatter<_CharT[_Size], _CharT>
 114     : public __formatter_string<_CharT> {
 115   using _Base = __formatter_string<_CharT>;
 116
 117   template <class _FormatContext>
 118   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
 119   format(const _CharT (&__str)[_Size], _FormatContext& __ctx) const {
 120     return _Base::format(basic_string_view<_CharT>(__str, _Size), __ctx);
 121   }
 122 };
 123
 124 // Formatter std::string.
 125 template <__fmt_char_type _CharT, class _Traits, class _Allocator>
 126 struct _LIBCPP_TEMPLATE_VIS formatter<basic_string<_CharT, _Traits, _Allocator>, _CharT>
 127     : public __formatter_string<_CharT> {
 128   using _Base = __formatter_string<_CharT>;
 129
 130   template <class _FormatContext>
 131   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
 132   format(const basic_string<_CharT, _Traits, _Allocator>& __str, _FormatContext& __ctx) const {
 133     // Drop _Traits and _Allocator to have one std::basic_string formatter.
 134     return _Base::format(basic_string_view<_CharT>(__str.data(), __str.size()), __ctx);
 135   }
 136 };
 137
 138 // Formatter std::string_view.
 139 template <__fmt_char_type _CharT, class _Traits>
 140 struct _LIBCPP_TEMPLATE_VIS formatter<basic_string_view<_CharT, _Traits>, _CharT>
 141     : public __formatter_string<_CharT> {
 142   using _Base = __formatter_string<_CharT>;
 143
 144   template <class _FormatContext>
 145   _LIBCPP_HIDE_FROM_ABI typename _FormatContext::iterator
 146   format(basic_string_view<_CharT, _Traits> __str, _FormatContext& __ctx) const {
 147     // Drop _Traits to have one std::basic_string_view formatter.
 148     return _Base::format(basic_string_view<_CharT>(__str.data(), __str.size()), __ctx);
 149   }
 150 };
 151
 152 #endif //_LIBCPP_STD_VER >= 20
 153
 154 _LIBCPP_END_NAMESPACE_STD
 155
 156 #endif // _LIBCPP___FORMAT_FORMATTER_STRING_H