3 // Copyright (C) 2007 Free Software Foundation, Inc.
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 terms
7 // of the GNU General Public License as published by the Free Software
8 // Foundation; either version 2, or (at your option) any later
11 // This library is distributed in the hope that it will be useful, but
12 // WITHOUT ANY WARRANTY; without even the implied warranty of
13 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 // General Public License for more details.
16 // You should have received a copy of the GNU General Public License
17 // along with this library; see the file COPYING. If not, write to
18 // the Free Software Foundation, 59 Temple Place - Suite 330, Boston,
19 // MA 02111-1307, USA.
21 // As a special exception, you may use this file as part of a free
22 // software library without restriction. Specifically, if other files
23 // instantiate templates or use macros or inline functions from this
24 // file, or you compile this file and link it with other files to
25 // produce an executable, this file does not by itself cause the
26 // resulting executable to be covered by the GNU General Public
27 // License. This exception does not however invalidate any other
28 // reasons why the executable file might be covered by the GNU General
31 /** @file parallel/base.h
32 * @brief Sequential helper functions.
33 * This file is a GNU parallel extension to the Standard C++ Library.
36 // Written by Johannes Singler.
38 #ifndef _GLIBCXX_PARALLEL_BASE_H
39 #define _GLIBCXX_PARALLEL_BASE_H 1
41 #include <parallel/features.h>
43 #include <parallel/basic_iterator.h>
44 #include <parallel/parallel.h>
47 namespace __gnu_parallel
49 // XXX remove std::duplicates from here if possible,
50 // XXX but keep minimal dependencies.
52 /** @brief Calculates the rounded-down logrithm of @c n for base 2.
54 * @return Returns 0 for argument 0.
56 template<typename Size>
61 for (k = 0; n != 1; n >>= 1)
66 /** @brief Encode two integers into one __gnu_parallel::lcas_t.
67 * @param a First integer, to be encoded in the most-significant @c
69 * @param b Second integer, to be encoded in the least-significant
70 * @c lcas_t_bits/2 bits.
71 * @return __gnu_parallel::lcas_t value encoding @c a and @c b.
75 encode2(int a, int b) //must all be non-negative, actually
77 return (((lcas_t)a) << (lcas_t_bits / 2)) | (((lcas_t)b) << 0);
80 /** @brief Decode two integers from one __gnu_parallel::lcas_t.
81 * @param x __gnu_parallel::lcas_t to decode integers from.
82 * @param a First integer, to be decoded from the most-significant
83 * @c lcas_t_bits/2 bits of @c x.
84 * @param b Second integer, to be encoded in the least-significant
85 * @c lcas_t_bits/2 bits of @c x.
89 decode2(lcas_t x, int& a, int& b)
91 a = (int)((x >> (lcas_t_bits / 2)) & lcas_t_mask);
92 b = (int)((x >> 0 ) & lcas_t_mask);
95 /** @brief Constructs predicate for equality from strict weak
98 // XXX comparator at the end, as per others
99 template<typename Comparator, typename T1, typename T2>
100 class equal_from_less : public std::binary_function<T1, T2, bool>
106 equal_from_less(Comparator& _comp) : comp(_comp) { }
108 bool operator()(const T1& a, const T2& b)
110 // FIXME: wrong in general (T1 != T2)
111 return !comp(a, b) && !comp(b, a);
116 /** @brief Similar to std::equal_to, but allows two different types. */
117 template<typename T1, typename T2>
118 struct equal_to : std::binary_function<T1, T2, bool>
120 bool operator()(const T1& t1, const T2& t2) const
124 /** @brief Similar to std::binder1st, but giving the argument types explicitly. */
125 template<typename _Predicate, typename argument_type>
127 : public std::unary_function<argument_type, bool>
134 unary_negate(const _Predicate& __x) : _M_pred(__x) { }
137 operator()(const argument_type& __x)
138 { return !_M_pred(__x); }
141 /** @brief Similar to std::binder1st, but giving the argument types explicitly. */
142 template<typename _Operation, typename first_argument_type, typename second_argument_type, typename result_type>
144 : public std::unary_function<second_argument_type, result_type>
148 first_argument_type value;
151 binder1st(const _Operation& __x,
152 const first_argument_type& __y)
153 : op(__x), value(__y) { }
156 operator()(const second_argument_type& __x)
157 { return op(value, __x); }
159 // _GLIBCXX_RESOLVE_LIB_DEFECTS
160 // 109. Missing binders for non-const sequence elements
162 operator()(second_argument_type& __x) const
163 { return op(value, __x); }
167 * @brief Similar to std::binder2nd, but giving the argument types
170 template<typename _Operation, typename first_argument_type, typename second_argument_type, typename result_type>
172 : public std::unary_function<first_argument_type, result_type>
176 second_argument_type value;
179 binder2nd(const _Operation& __x,
180 const second_argument_type& __y)
181 : op(__x), value(__y) { }
184 operator()(const first_argument_type& __x) const
185 { return op(__x, value); }
187 // _GLIBCXX_RESOLVE_LIB_DEFECTS
188 // 109. Missing binders for non-const sequence elements
190 operator()(first_argument_type& __x)
191 { return op(__x, value); }
194 /** @brief Similar to std::less, but allows two different types. */
195 template<typename T1, typename T2>
196 struct less : std::binary_function<T1, T2, bool>
199 operator()(const T1& t1, const T2& t2) const
203 operator()(const T2& t2, const T1& t1) const
207 // Partial specialization for one type. Same as std::less.
208 template<typename _Tp>
209 struct less<_Tp, _Tp> : public std::binary_function<_Tp, _Tp, bool>
212 operator()(const _Tp& __x, const _Tp& __y) const
213 { return __x < __y; }
216 template<typename T, typename _DifferenceTp>
217 class pseudo_sequence;
219 /** @brief Iterator associated with __gnu_parallel::pseudo_sequence.
220 * If features the usual random-access iterator functionality.
221 * @param T Sequence value type.
222 * @param difference_type Sequence difference type.
224 template<typename T, typename _DifferenceTp>
225 class pseudo_sequence_iterator
228 typedef _DifferenceTp difference_type;
231 typedef pseudo_sequence_iterator<T, _DifferenceTp> type;
237 pseudo_sequence_iterator(const T& val, difference_type pos)
238 : val(val), pos(pos) { }
240 // Pre-increment operator.
248 // Post-increment operator.
251 { return type(pos++); }
258 operator[](difference_type) const
262 operator==(const type& i2)
263 { return pos == i2.pos; }
266 operator!=(const type& i2)
267 { return pos != i2.pos; }
270 operator-(const type& i2)
271 { return pos - i2.pos; }
274 /** @brief Sequence that conceptually consists of multiple copies of
276 * The copies are not stored explicitly, of course.
277 * @param T Sequence value type.
278 * @param difference_type Sequence difference type.
280 template<typename T, typename _DifferenceTp>
281 class pseudo_sequence
283 typedef pseudo_sequence<T, _DifferenceTp> type;
286 typedef _DifferenceTp difference_type;
288 // Better case down to uint64, than up to _DifferenceTp.
289 typedef pseudo_sequence_iterator<T, uint64> iterator;
291 /** @brief Constructor.
292 * @param val Element of the sequence.
293 * @param count Number of (virtual) copies.
295 pseudo_sequence(const T& val, difference_type count)
296 : val(val), count(count) { }
298 /** @brief Begin iterator. */
301 { return iterator(val, 0); }
303 /** @brief End iterator. */
306 { return iterator(val, count); }
310 difference_type count;
313 /** @brief Functor that does nothing */
314 template<typename _ValueTp>
318 operator()(const _ValueTp& v) const { }
321 /** @brief Compute the median of three referenced elements,
322 according to @c comp.
323 * @param a First iterator.
324 * @param b Second iterator.
325 * @param c Third iterator.
326 * @param comp Comparator.
328 template<typename RandomAccessIterator, typename Comparator>
330 median_of_three_iterators(RandomAccessIterator a, RandomAccessIterator b,
331 RandomAccessIterator c, Comparator& comp)
343 // Just swap a and b.
354 // Avoid the use of assert, because we're trying to keep the <cassert>
355 // include out of the mix. (Same as debug mode).
357 __replacement_assert(const char* __file, int __line,
358 const char* __function, const char* __condition)
360 std::printf("%s:%d: %s: Assertion '%s' failed.\n", __file, __line,
361 __function, __condition);
365 #define _GLIBCXX_PARALLEL_ASSERT(_Condition) \
369 __gnu_parallel::__replacement_assert(__FILE__, __LINE__, \
370 __PRETTY_FUNCTION__, #_Condition); \
373 } //namespace __gnu_parallel