libstdc++
experimental/functional
Go to the documentation of this file.
1 // <experimental/functional> -*- C++ -*-
2 
3 // Copyright (C) 2014-2022 Free Software Foundation, Inc.
4 //
5 // This file is part of the GNU ISO C++ Library. This library is free
6 // software; you can redistribute it and/or modify it under the
7 // terms of the GNU General Public License as published by the
8 // Free Software Foundation; either version 3, or (at your option)
9 // any later version.
10 
11 // This library is distributed in the hope that it will be useful,
12 // but WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 // GNU General Public License for more details.
15 
16 // Under Section 7 of GPL version 3, you are granted additional
17 // permissions described in the GCC Runtime Library Exception, version
18 // 3.1, as published by the Free Software Foundation.
19 
20 // You should have received a copy of the GNU General Public License and
21 // a copy of the GCC Runtime Library Exception along with this program;
22 // see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
23 // <http://www.gnu.org/licenses/>.
24 
25 /** @file experimental/functional
26  * This is a TS C++ Library header.
27  * @ingroup libfund-ts
28  */
29 
30 #ifndef _GLIBCXX_EXPERIMENTAL_FUNCTIONAL
31 #define _GLIBCXX_EXPERIMENTAL_FUNCTIONAL 1
32 
33 #pragma GCC system_header
34 
35 #if __cplusplus >= 201402L
36 
37 #include <functional>
38 #include <tuple>
39 #include <iterator>
40 #include <unordered_map>
41 #include <vector>
42 #include <array>
43 #include <bits/stl_algo.h>
44 #ifdef _GLIBCXX_PARALLEL
45 # include <parallel/algorithm> // For std::__parallel::search
46 #endif
47 #include <experimental/bits/lfts_config.h>
48 
49 namespace std _GLIBCXX_VISIBILITY(default)
50 {
51 _GLIBCXX_BEGIN_NAMESPACE_VERSION
52 
53 namespace experimental
54 {
55 inline namespace fundamentals_v1
56 {
57  // See C++14 20.9.9, Function object binders
58 
59  /// Variable template for std::is_bind_expression
60  template<typename _Tp>
61  constexpr bool is_bind_expression_v = std::is_bind_expression<_Tp>::value;
62 
63  /// Variable template for std::is_placeholder
64  template<typename _Tp>
65  constexpr int is_placeholder_v = std::is_placeholder<_Tp>::value;
66 
67 #define __cpp_lib_experimental_boyer_moore_searching 201411
68 
69  // Searchers
70 
71  template<typename _ForwardIterator1, typename _BinaryPredicate = equal_to<>>
72  class default_searcher
73  {
74  public:
75  default_searcher(_ForwardIterator1 __pat_first,
76  _ForwardIterator1 __pat_last,
77  _BinaryPredicate __pred = _BinaryPredicate())
78  : _M_m(__pat_first, __pat_last, std::move(__pred))
79  { }
80 
81  template<typename _ForwardIterator2>
82  _ForwardIterator2
83  operator()(_ForwardIterator2 __first, _ForwardIterator2 __last) const
84  {
85  return std::search(__first, __last,
86  std::get<0>(_M_m), std::get<1>(_M_m),
87  std::get<2>(_M_m));
88  }
89 
90  private:
91  std::tuple<_ForwardIterator1, _ForwardIterator1, _BinaryPredicate> _M_m;
92  };
93 
94  template<typename _Key, typename _Tp, typename _Hash, typename _Pred>
95  struct __boyer_moore_map_base
96  {
97  template<typename _RAIter>
98  __boyer_moore_map_base(_RAIter __pat, size_t __patlen,
99  _Hash&& __hf, _Pred&& __pred)
100  : _M_bad_char{ __patlen, std::move(__hf), std::move(__pred) }
101  {
102  if (__patlen > 0)
103  for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
104  _M_bad_char[__pat[__i]] = __patlen - 1 - __i;
105  }
106 
107  using __diff_type = _Tp;
108 
109  __diff_type
110  _M_lookup(_Key __key, __diff_type __not_found) const
111  {
112  auto __iter = _M_bad_char.find(__key);
113  if (__iter == _M_bad_char.end())
114  return __not_found;
115  return __iter->second;
116  }
117 
118  _Pred
119  _M_pred() const { return _M_bad_char.key_eq(); }
120 
121  _GLIBCXX_STD_C::unordered_map<_Key, _Tp, _Hash, _Pred> _M_bad_char;
122  };
123 
124  template<typename _Tp, size_t _Len, typename _Pred>
125  struct __boyer_moore_array_base
126  {
127  template<typename _RAIter, typename _Unused>
128  __boyer_moore_array_base(_RAIter __pat, size_t __patlen,
129  _Unused&&, _Pred&& __pred)
130  : _M_bad_char{ std::array<_Tp, _Len>{}, std::move(__pred) }
131  {
132  std::get<0>(_M_bad_char).fill(__patlen);
133  if (__patlen > 0)
134  for (__diff_type __i = 0; __i < __patlen - 1; ++__i)
135  {
136  auto __ch = __pat[__i];
137  using _UCh = std::make_unsigned_t<decltype(__ch)>;
138  auto __uch = static_cast<_UCh>(__ch);
139  std::get<0>(_M_bad_char)[__uch] = __patlen - 1 - __i;
140  }
141  }
142 
143  using __diff_type = _Tp;
144 
145  template<typename _Key>
146  __diff_type
147  _M_lookup(_Key __key, __diff_type __not_found) const
148  {
149  auto __ukey = static_cast<std::make_unsigned_t<_Key>>(__key);
150  if (__ukey >= _Len)
151  return __not_found;
152  return std::get<0>(_M_bad_char)[__ukey];
153  }
154 
155  const _Pred&
156  _M_pred() const { return std::get<1>(_M_bad_char); }
157 
158  std::tuple<std::array<_Tp, _Len>, _Pred> _M_bad_char;
159  };
160 
161  // Use __boyer_moore_array_base when pattern consists of narrow characters
162  // (or std::byte) and uses std::equal_to as the predicate.
163  template<typename _RAIter, typename _Hash, typename _Pred,
164  typename _Val = typename iterator_traits<_RAIter>::value_type,
165  typename _Diff = typename iterator_traits<_RAIter>::difference_type>
166  using __boyer_moore_base_t
167  = std::__conditional_t<std::__is_byte_like<_Val, _Pred>::value,
168  __boyer_moore_array_base<_Diff, 256, _Pred>,
169  __boyer_moore_map_base<_Val, _Diff, _Hash, _Pred>>;
170 
171  template<typename _RAIter, typename _Hash
172  = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
173  typename _BinaryPredicate = std::equal_to<>>
174  class boyer_moore_searcher
175  : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
176  {
177  using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
178  using typename _Base::__diff_type;
179 
180  public:
181  boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
182  _Hash __hf = _Hash(),
183  _BinaryPredicate __pred = _BinaryPredicate());
184 
185  template<typename _RandomAccessIterator2>
186  _RandomAccessIterator2
187  operator()(_RandomAccessIterator2 __first,
188  _RandomAccessIterator2 __last) const;
189 
190  private:
191  bool
192  _M_is_prefix(_RAIter __word, __diff_type __len,
193  __diff_type __pos)
194  {
195  const auto& __pred = this->_M_pred();
196  __diff_type __suffixlen = __len - __pos;
197  for (__diff_type __i = 0; __i < __suffixlen; ++__i)
198  if (!__pred(__word[__i], __word[__pos + __i]))
199  return false;
200  return true;
201  }
202 
203  __diff_type
204  _M_suffix_length(_RAIter __word, __diff_type __len,
205  __diff_type __pos)
206  {
207  const auto& __pred = this->_M_pred();
208  __diff_type __i = 0;
209  while (__pred(__word[__pos - __i], __word[__len - 1 - __i])
210  && __i < __pos)
211  {
212  ++__i;
213  }
214  return __i;
215  }
216 
217  template<typename _Tp>
218  __diff_type
219  _M_bad_char_shift(_Tp __c) const
220  { return this->_M_lookup(__c, _M_pat_end - _M_pat); }
221 
222  _RAIter _M_pat;
223  _RAIter _M_pat_end;
224  _GLIBCXX_STD_C::vector<__diff_type> _M_good_suffix;
225  };
226 
227  template<typename _RAIter, typename _Hash
228  = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
229  typename _BinaryPredicate = std::equal_to<>>
230  class boyer_moore_horspool_searcher
231  : __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>
232  {
233  using _Base = __boyer_moore_base_t<_RAIter, _Hash, _BinaryPredicate>;
234  using typename _Base::__diff_type;
235 
236  public:
237  boyer_moore_horspool_searcher(_RAIter __pat,
238  _RAIter __pat_end,
239  _Hash __hf = _Hash(),
240  _BinaryPredicate __pred
241  = _BinaryPredicate())
242  : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
243  _M_pat(__pat), _M_pat_end(__pat_end)
244  { }
245 
246  template<typename _RandomAccessIterator2>
247  _RandomAccessIterator2
248  operator()(_RandomAccessIterator2 __first,
249  _RandomAccessIterator2 __last) const
250  {
251  const auto& __pred = this->_M_pred();
252  auto __patlen = _M_pat_end - _M_pat;
253  if (__patlen == 0)
254  return __first;
255  auto __len = __last - __first;
256  while (__len >= __patlen)
257  {
258  for (auto __scan = __patlen - 1;
259  __pred(__first[__scan], _M_pat[__scan]); --__scan)
260  if (__scan == 0)
261  return __first;
262  auto __shift = _M_bad_char_shift(__first[__patlen - 1]);
263  __len -= __shift;
264  __first += __shift;
265  }
266  return __last;
267  }
268 
269  private:
270  template<typename _Tp>
271  __diff_type
272  _M_bad_char_shift(_Tp __c) const
273  { return this->_M_lookup(__c, _M_pat_end - _M_pat); }
274 
275  _RAIter _M_pat;
276  _RAIter _M_pat_end;
277  };
278 
279  /// Generator function for default_searcher
280  template<typename _ForwardIterator,
281  typename _BinaryPredicate = std::equal_to<>>
282  inline default_searcher<_ForwardIterator, _BinaryPredicate>
283  make_default_searcher(_ForwardIterator __pat_first,
284  _ForwardIterator __pat_last,
285  _BinaryPredicate __pred = _BinaryPredicate())
286  { return { __pat_first, __pat_last, __pred }; }
287 
288  /// Generator function for boyer_moore_searcher
289  template<typename _RAIter, typename _Hash
290  = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
291  typename _BinaryPredicate = equal_to<>>
292  inline boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>
293  make_boyer_moore_searcher(_RAIter __pat_first, _RAIter __pat_last,
294  _Hash __hf = _Hash(),
295  _BinaryPredicate __pred = _BinaryPredicate())
296  { return { __pat_first, __pat_last, std::move(__hf), std::move(__pred) }; }
297 
298  /// Generator function for boyer_moore_horspool_searcher
299  template<typename _RAIter, typename _Hash
300  = std::hash<typename std::iterator_traits<_RAIter>::value_type>,
301  typename _BinaryPredicate = equal_to<>>
302  inline boyer_moore_horspool_searcher<_RAIter, _Hash, _BinaryPredicate>
303  make_boyer_moore_horspool_searcher(_RAIter __pat_first, _RAIter __pat_last,
304  _Hash __hf = _Hash(),
305  _BinaryPredicate __pred
306  = _BinaryPredicate())
307  { return { __pat_first, __pat_last, std::move(__hf), std::move(__pred) }; }
308 
309  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
310  boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
311  boyer_moore_searcher(_RAIter __pat, _RAIter __pat_end,
312  _Hash __hf, _BinaryPredicate __pred)
313  : _Base(__pat, __pat_end - __pat, std::move(__hf), std::move(__pred)),
314  _M_pat(__pat), _M_pat_end(__pat_end), _M_good_suffix(__pat_end - __pat)
315  {
316  auto __patlen = __pat_end - __pat;
317  if (__patlen == 0)
318  return;
319  __diff_type __last_prefix = __patlen - 1;
320  for (__diff_type __p = __patlen - 1; __p >= 0; --__p)
321  {
322  if (_M_is_prefix(__pat, __patlen, __p + 1))
323  __last_prefix = __p + 1;
324  _M_good_suffix[__p] = __last_prefix + (__patlen - 1 - __p);
325  }
326  for (__diff_type __p = 0; __p < __patlen - 1; ++__p)
327  {
328  auto __slen = _M_suffix_length(__pat, __patlen, __p);
329  auto __pos = __patlen - 1 - __slen;
330  if (!__pred(__pat[__p - __slen], __pat[__pos]))
331  _M_good_suffix[__pos] = __patlen - 1 - __p + __slen;
332  }
333  }
334 
335  template<typename _RAIter, typename _Hash, typename _BinaryPredicate>
336  template<typename _RandomAccessIterator2>
337  _RandomAccessIterator2
338  boyer_moore_searcher<_RAIter, _Hash, _BinaryPredicate>::
339  operator()(_RandomAccessIterator2 __first,
340  _RandomAccessIterator2 __last) const
341  {
342  auto __patlen = _M_pat_end - _M_pat;
343  if (__patlen == 0)
344  return __first;
345  const auto& __pred = this->_M_pred();
346  __diff_type __i = __patlen - 1;
347  auto __stringlen = __last - __first;
348  while (__i < __stringlen)
349  {
350  __diff_type __j = __patlen - 1;
351  while (__j >= 0 && __pred(__first[__i], _M_pat[__j]))
352  {
353  --__i;
354  --__j;
355  }
356  if (__j < 0)
357  return __first + __i + 1;
358  __i += std::max(_M_bad_char_shift(__first[__i]),
359  _M_good_suffix[__j]);
360  }
361  return __last;
362  }
363 } // namespace fundamentals_v1
364 
365 inline namespace fundamentals_v2
366 {
367 #define __cpp_lib_experimental_not_fn 201406
368 
369  /// [func.not_fn] Function template not_fn
370  template<typename _Fn>
371  inline auto
372  not_fn(_Fn&& __fn)
373  noexcept(std::is_nothrow_constructible<std::decay_t<_Fn>, _Fn&&>::value)
374  {
375  return std::_Not_fn<std::decay_t<_Fn>>{std::forward<_Fn>(__fn), 0};
376  }
377 } // namespace fundamentals_v2
378 } // namespace experimental
379 
380 _GLIBCXX_END_NAMESPACE_VERSION
381 } // namespace std
382 
383 #endif // C++14
384 
385 #endif // _GLIBCXX_EXPERIMENTAL_FUNCTIONAL