experimental/functional

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// <experimental/functional> -*- C++ -*-
 
// Copyright (C) 2014-2025 Free Software Foundation, Inc.
//
// This file is part of the GNU ISO C++ Library.  This library is free
// software; you can redistribute it and/or modify it under the
// terms of the GNU General Public License as published by the
// Free Software Foundation; either version 3, or (at your option)
// any later version.
 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
 
// Under Section 7 of GPL version 3, you are granted additional
// permissions described in the GCC Runtime Library Exception, version
// 3.1, as published by the Free Software Foundation.
 
// You should have received a copy of the GNU General Public License and
// a copy of the GCC Runtime Library Exception along with this program;
// see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
// <http://www.gnu.org/licenses/>.
 
/** @file experimental/functional
 *  This is a TS C++ Library header.
 *  @ingroup libfund-ts
 */
 
#ifndef _GLIBCXX_EXPERIMENTAL_FUNCTIONAL
#define _GLIBCXX_EXPERIMENTAL_FUNCTIONAL 1
 
#ifdef _GLIBCXX_SYSHDR
#pragma GCC system_header
#endif
 
#include <bits/requires_hosted.h> // experimental is currently omitted
 
#if __cplusplus >= 201402L
 
#include <functional>
#include <tuple>
#include <iterator>
#include <unordered_map>
#include <vector>
#include <array>
#include <bits/stl_algobase.h> // std::max, std::search
#include <experimental/bits/lfts_config.h>
 
namespace std _GLIBCXX_VISIBILITY(default)
{
_GLIBCXX_BEGIN_NAMESPACE_VERSION
 
namespace experimental
{
inline namespace fundamentals_v1
{
  // See C++14 20.9.9, Function object binders
 
  /// Variable template for std::is_bind_expression
  template<typename _Tp>
    constexpr bool is_bind_expression_v = std::is_bind_expression<_Tp>::value;
 
  /// Variable template for std::is_placeholder
  template<typename _Tp>
    constexpr int is_placeholder_v = std::is_placeholder<_Tp>::value;
 
#define __cpp_lib_experimental_boyer_moore_searching 201411
 
  // Searchers
 
  template<typename _ForwardIterator1, typename _BinaryPredicate = equal_to<>>
    class default_searcher
    {
    public:
      default_searcher(_ForwardIterator1 __pat_first,
                       _ForwardIterator1 __pat_last,
                       _BinaryPredicate __pred = _BinaryPredicate())
      : _M_m(__pat_first, __pat_last, std::move(__pred))
      { }
 
      template<typename _ForwardIterator2>
        _ForwardIterator2
        operator()(_ForwardIterator2 __first, _ForwardIterator2 __last) const
        {
          return std::search(__first, __last,
                             std::get<0>(_M_m), std::get<1>(_M_m),
                             std::get<2>(_M_m));
        }
 
    private:
      std::tuple<_ForwardIterator1, _ForwardIterator1, _BinaryPredicate> _M_m;
    };
 
  template<typename _Key, typename _Tp, typename _Hash, typename _Pred>
    struct __boyer_moore_map_base
    {
      template<typename _RAIter>
        __boyer_moore_map_base(_RAIter __pat, size_t __patlen,
                               _Hash&& __hf, _Pred&& __pred)
        : _M_bad_char{ __patlen, std::move(__hf), std::move(__pred) }
        {
          if (__patlen > 0)
            for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
              _M_bad_char[__pat[__i]] = __patlen - 1 - __i;
        }
 
      using __diff_type = _Tp;
 
      __diff_type
      _M_lookup(_Key __key, __diff_type __not_found) const
      {
        auto __iter = _M_bad_char.find(__key);
        if (__iter == _M_bad_char.end())
          return __not_found;
        return __iter->second;
      }
 
      _Pred
      _M_pred() const { return _M_bad_char.key_eq(); }
 
      _GLIBCXX_STD_C::unordered_map<_Key, _Tp, _Hash, _Pred> _M_bad_char;
    };
 
  template<typename _Tp, size_t _Len, typename _Pred>
    struct __boyer_moore_array_base
    {
      template<typename _RAIter, typename _Unused>
        __boyer_moore_array_base(_RAIter __pat, size_t __patlen,
                                 _Unused&&, _Pred&& __pred)
        : _M_bad_char{ std::array<_Tp, _Len>{}, std::move(__pred) }
        {
          std::get<0>(_M_bad_char).fill(__patlen);
          if (__patlen > 0)
            for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
              {
                auto __ch = __pat[__i];
                using _UCh = std::make_unsigned_t<decltype(__ch)>;
                auto __uch = static_cast<_UCh>(__ch);
                std::get<0>(_M_bad_char)[__uch] = __patlen - 1 - __i;
              }
        }
 
      using __diff_type = _Tp;
 
      template<typename _Key>
        __diff_type
        _M_lookup(_Key __key, __diff_type __not_found) const
        {
          auto __ukey = static_cast<std::make_unsigned_t<_Key>>(__key);
          if (__ukey >= _Len)
            return __not_found;
          return std::get<0>(_M_bad_char)[__ukey];
        }
 
      const _Pred&
      _M_pred() const { return std::get<1>(_M_bad_char); }
 
      std::tuple<std::array<_Tp, _Len>, _Pred> _M_bad_char;
    };
 
  // Use __boyer_moore_array_base when pattern consists of narrow characters
  // (or std::byte) and uses std::equal_to as the predicate.
  template<typename _RAIter, typename _Hash, typename _Pred,
           typename _Val = typename iterator_traits<_RAIter>::value_type,
           typename _Diff = typename iterator_traits<_RAIter>::difference_type>
    using __boyer_moore_base_t
      = std::__conditional_t<std::__is_byte_like<_Val, _Pred>::value,
                             __boyer_moore_array_base<_Diff, 256, _Pred>,
                             __boyer_moore_map_base<_Val, _Diff, _Hash, _Pred>>;
 
  template<typename _RAIter, typename _Hash
             = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
           typename _BinaryPredicate = std::equal_to<>>
    class boyer_moore_searcher
    : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
    {
      using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
      using typename _Base::__diff_type;
 
    public:
      boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
                           _Hash __hf = _Hash(),
                           _BinaryPredicate __pred = _BinaryPredicate());
 
      template<typename _RandomAccessIterator2>
        _RandomAccessIterator2
        operator()(_RandomAccessIterator2 __first,
                   _RandomAccessIterator2 __last) const;
 
    private:
      bool
      _M_is_prefix(_RAIter __word, __diff_type __len,
                   __diff_type __pos)
      {
        const auto& __pred = this->_M_pred();
        __diff_type __suffixlen = __len - __pos;
        for (__diff_type __i = 0; __i < __suffixlen; ++__i)
          if (!__pred(__word[__i], __word[__pos + __i]))
            return false;
        return true;
      }
 
      __diff_type
      _M_suffix_length(_RAIter __word, __diff_type __len,
                       __diff_type __pos)
      {
        const auto& __pred = this->_M_pred();
        __diff_type __i = 0;
        while (__pred(__word[__pos - __i], __word[__len - 1 - __i])
               && __i < __pos)
          {
            ++__i;
          }
        return __i;
      }
 
      template<typename _Tp>
        __diff_type
        _M_bad_char_shift(_Tp __c) const
        { return this->_M_lookup(__c, _M_pat_end - _M_pat); }
 
      _RAIter _M_pat;
      _RAIter _M_pat_end;
      _GLIBCXX_STD_C::vector<__diff_type> _M_good_suffix;
    };
 
  template<typename _RAIter, typename _Hash
             = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
           typename _BinaryPredicate = std::equal_to<>>
    class boyer_moore_horspool_searcher
    : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
    {
      using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
      using typename _Base::__diff_type;
 
    public:
      boyer_moore_horspool_searcher(_RAIter __pat,
                                    _RAIter __pat_end,
                                    _Hash __hf = _Hash(),
                                    _BinaryPredicate __pred
                                    = _BinaryPredicate())
      : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
        _M_pat(__pat), _M_pat_end(__pat_end)
      { }
 
      template<typename _RandomAccessIterator2>
        _RandomAccessIterator2
        operator()(_RandomAccessIterator2 __first,
                   _RandomAccessIterator2 __last) const
        {
          const auto& __pred = this->_M_pred();
          auto __patlen = _M_pat_end - _M_pat;
          if (__patlen == 0)
            return __first;
          auto __len = __last - __first;
          while (__len >= __patlen)
            {
              for (auto __scan = __patlen - 1;
                   __pred(__first[__scan], _M_pat[__scan]); --__scan)
                if (__scan == 0)
                  return __first;
              auto __shift = _M_bad_char_shift(__first[__patlen - 1]);
              __len -= __shift;
              __first += __shift;
            }
          return __last;
        }
 
    private:
      template<typename _Tp>
        __diff_type
        _M_bad_char_shift(_Tp __c) const
        { return this->_M_lookup(__c, _M_pat_end - _M_pat); }
 
      _RAIter _M_pat;
      _RAIter _M_pat_end;
    };
 
  /// Generator function for default_searcher
  template<typename _ForwardIterator,
           typename _BinaryPredicate = std::equal_to<>>
    inline default_searcher<_ForwardIterator, _BinaryPredicate>
    make_default_searcher(_ForwardIterator __pat_first,
                          _ForwardIterator __pat_last,
                          _BinaryPredicate __pred = _BinaryPredicate())
    { return { __pat_first, __pat_last, __pred }; }
 
  /// Generator function for boyer_moore_searcher
  template<typename _RAIter, typename _Hash
             = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
           typename _BinaryPredicate = equal_to<>>
    inline boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>
    make_boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
                              _Hash __hf = _Hash(),
                              _BinaryPredicate __pred = _BinaryPredicate())
    { return { __pat_first, __pat_last, std::move(__hf), std::move(__pred) }; }
 
  /// Generator function for boyer_moore_horspool_searcher
  template<typename _RAIter, typename _Hash
             = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
           typename _BinaryPredicate = equal_to<>>
    inline boyer_moore_horspool_searcher<_RAIter, _Hash, _BinaryPredicate>
    make_boyer_moore_horspool_searcher(_RAIter __pat_first, _RAIter __pat_last,
                                       _Hash __hf = _Hash(),
                                       _BinaryPredicate __pred
                                       = _BinaryPredicate())
    { return { __pat_first, __pat_last, std::move(__hf), std::move(__pred) }; }
 
  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
    boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
    boyer_moore_searcher(_RAIter __pat, _RAIter __pat_end,
                         _Hash __hf, _BinaryPredicate __pred)
    : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
      _M_pat(__pat), _M_pat_end(__pat_end), _M_good_suffix(__pat_end - __pat)
    {
      auto __patlen = __pat_end - __pat;
      if (__patlen == 0)
        return;
      __diff_type __last_prefix = __patlen - 1;
      for (__diff_type __p = __patlen - 1; __p >= 0; --__p)
        {
          if (_M_is_prefix(__pat, __patlen, __p + 1))
            __last_prefix = __p + 1;
          _M_good_suffix[__p] = __last_prefix + (__patlen - 1 - __p);
        }
      for (__diff_type __p = 0; __p < __patlen - 1; ++__p)
        {
          auto __slen = _M_suffix_length(__pat, __patlen, __p);
          auto __pos = __patlen - 1 - __slen;
          if (!__pred(__pat[__p - __slen], __pat[__pos]))
            _M_good_suffix[__pos] = __patlen - 1 - __p + __slen;
        }
    }
 
  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
  template<typename _RandomAccessIterator2>
    _RandomAccessIterator2
    boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
    operator()(_RandomAccessIterator2 __first,
               _RandomAccessIterator2 __last) const
    {
      auto __patlen = _M_pat_end - _M_pat;
      if (__patlen == 0)
        return __first;
      const auto& __pred = this->_M_pred();
      __diff_type __i = __patlen - 1;
      auto __stringlen = __last - __first;
      while (__i < __stringlen)
        {
          __diff_type __j = __patlen - 1;
          while (__j >= 0 && __pred(__first[__i], _M_pat[__j]))
            {
              --__i;
              --__j;
            }
          if (__j < 0)
            return __first + __i + 1;
          __i += std::max(_M_bad_char_shift(__first[__i]),
                          _M_good_suffix[__j]);
        }
      return __last;
    }
} // namespace fundamentals_v1
 
inline namespace fundamentals_v2
{
#define __cpp_lib_experimental_not_fn 201406
 
  /// [func.not_fn] Function template not_fn
  template<typename _Fn>
    inline auto
    not_fn(_Fn&& __fn)
    noexcept(std::is_nothrow_constructible<std::decay_t<_Fn>, _Fn&&>::value)
    {
      return std::_Not_fn<std::decay_t<_Fn>>{std::forward<_Fn>(__fn), 0};
    }
} // namespace fundamentals_v2
} // namespace experimental
 
_GLIBCXX_END_NAMESPACE_VERSION
} // namespace std
 
#endif // C++14
 
#endif // _GLIBCXX_EXPERIMENTAL_FUNCTIONAL