vendor/llvm-project/llvmorg-16-init-18548-gb0daacf58f41

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
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+++ 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