xref: /freebsd-12.1/contrib/libc++/include/numeric (revision cc65eb4e) 
1// -*- C++ -*-
2//===---------------------------- numeric ---------------------------------===//
3//
4//                     The LLVM Compiler Infrastructure
5//
6// This file is dual licensed under the MIT and the University of Illinois Open
7// Source Licenses. See LICENSE.TXT for details.
8//
9//===----------------------------------------------------------------------===//
10
11#ifndef _LIBCPP_NUMERIC
12#define _LIBCPP_NUMERIC
13
14/*
15    numeric synopsis
16
17namespace std
18{
19
20template <class InputIterator, class T>
21    T
22    accumulate(InputIterator first, InputIterator last, T init);
23
24template <class InputIterator, class T, class BinaryOperation>
25    T
26    accumulate(InputIterator first, InputIterator last, T init, BinaryOperation binary_op);
27
28template <class InputIterator1, class InputIterator2, class T>
29    T
30    inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init);
31
32template <class InputIterator1, class InputIterator2, class T, class BinaryOperation1, class BinaryOperation2>
33    T
34    inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
35                  T init, BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);
36
37template <class InputIterator, class OutputIterator>
38    OutputIterator
39    partial_sum(InputIterator first, InputIterator last, OutputIterator result);
40
41template <class InputIterator, class OutputIterator, class BinaryOperation>
42    OutputIterator
43    partial_sum(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op);
44
45template <class InputIterator, class OutputIterator>
46    OutputIterator
47    adjacent_difference(InputIterator first, InputIterator last, OutputIterator result);
48
49template <class InputIterator, class OutputIterator, class BinaryOperation>
50    OutputIterator
51    adjacent_difference(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op);
52
53template <class ForwardIterator, class T>
54    void iota(ForwardIterator first, ForwardIterator last, T value);
55
56template <class M, class N>
57    constexpr common_type_t<M,N> gcd(M m, N n);    // C++17
58
59template <class M, class N>
60    constexpr common_type_t<M,N> lcm(M m, N n);    // C++17
61
62}  // std
63
64*/
65
66#include <__config>
67#include <iterator>
68
69#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
70#pragma GCC system_header
71#endif
72
73_LIBCPP_BEGIN_NAMESPACE_STD
74
75template <class _InputIterator, class _Tp>
76inline _LIBCPP_INLINE_VISIBILITY
77_Tp
78accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
79{
80    for (; __first != __last; ++__first)
81        __init = __init + *__first;
82    return __init;
83}
84
85template <class _InputIterator, class _Tp, class _BinaryOperation>
86inline _LIBCPP_INLINE_VISIBILITY
87_Tp
88accumulate(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOperation __binary_op)
89{
90    for (; __first != __last; ++__first)
91        __init = __binary_op(__init, *__first);
92    return __init;
93}
94
95template <class _InputIterator1, class _InputIterator2, class _Tp>
96inline _LIBCPP_INLINE_VISIBILITY
97_Tp
98inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _Tp __init)
99{
100    for (; __first1 != __last1; ++__first1, (void) ++__first2)
101        __init = __init + *__first1 * *__first2;
102    return __init;
103}
104
105template <class _InputIterator1, class _InputIterator2, class _Tp, class _BinaryOperation1, class _BinaryOperation2>
106inline _LIBCPP_INLINE_VISIBILITY
107_Tp
108inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
109              _Tp __init, _BinaryOperation1 __binary_op1, _BinaryOperation2 __binary_op2)
110{
111    for (; __first1 != __last1; ++__first1, (void) ++__first2)
112        __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
113    return __init;
114}
115
116template <class _InputIterator, class _OutputIterator>
117inline _LIBCPP_INLINE_VISIBILITY
118_OutputIterator
119partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
120{
121    if (__first != __last)
122    {
123        typename iterator_traits<_InputIterator>::value_type __t(*__first);
124        *__result = __t;
125        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
126        {
127            __t = __t + *__first;
128            *__result = __t;
129        }
130    }
131    return __result;
132}
133
134template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
135inline _LIBCPP_INLINE_VISIBILITY
136_OutputIterator
137partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
138              _BinaryOperation __binary_op)
139{
140    if (__first != __last)
141    {
142        typename iterator_traits<_InputIterator>::value_type __t(*__first);
143        *__result = __t;
144        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
145        {
146            __t = __binary_op(__t, *__first);
147            *__result = __t;
148        }
149    }
150    return __result;
151}
152
153template <class _InputIterator, class _OutputIterator>
154inline _LIBCPP_INLINE_VISIBILITY
155_OutputIterator
156adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
157{
158    if (__first != __last)
159    {
160        typename iterator_traits<_InputIterator>::value_type __t1(*__first);
161        *__result = __t1;
162        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
163        {
164            typename iterator_traits<_InputIterator>::value_type __t2(*__first);
165            *__result = __t2 - __t1;
166            __t1 = _VSTD::move(__t2);
167        }
168    }
169    return __result;
170}
171
172template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
173inline _LIBCPP_INLINE_VISIBILITY
174_OutputIterator
175adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
176                      _BinaryOperation __binary_op)
177{
178    if (__first != __last)
179    {
180        typename iterator_traits<_InputIterator>::value_type __t1(*__first);
181        *__result = __t1;
182        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
183        {
184            typename iterator_traits<_InputIterator>::value_type __t2(*__first);
185            *__result = __binary_op(__t2, __t1);
186            __t1 = _VSTD::move(__t2);
187        }
188    }
189    return __result;
190}
191
192template <class _ForwardIterator, class _Tp>
193inline _LIBCPP_INLINE_VISIBILITY
194void
195iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value_)
196{
197    for (; __first != __last; ++__first, (void) ++__value_)
198        *__first = __value_;
199}
200
201
202#if _LIBCPP_STD_VER > 14
203template <typename _Tp, bool _IsSigned = is_signed<_Tp>::value> struct __abs;
204
205template <typename _Tp>
206struct __abs<_Tp, true> {
207    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
208    _Tp operator()(_Tp __t) const noexcept { return __t >= 0 ? __t : -__t; }
209};
210
211template <typename _Tp>
212struct __abs<_Tp, false> {
213    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
214    _Tp operator()(_Tp __t) const noexcept { return __t; }
215};
216
217
218template<class _Tp>
219_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
220_Tp __gcd(_Tp __m, _Tp __n)
221{
222    static_assert((!is_signed<_Tp>::value), "" );
223    return __n == 0 ? __m : __gcd<_Tp>(__n, __m % __n);
224}
225
226
227template<class _Tp, class _Up>
228_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
229common_type_t<_Tp,_Up>
230gcd(_Tp __m, _Up __n)
231{
232    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
233    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to gcd cannot be bool" );
234    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to gcd cannot be bool" );
235    using _Rp = common_type_t<_Tp,_Up>;
236    using _Wp = make_unsigned_t<_Rp>;
237    return static_cast<_Rp>(__gcd(static_cast<_Wp>(__abs<_Tp>()(__m)),
238                                  static_cast<_Wp>(__abs<_Up>()(__n))));
239}
240
241template<class _Tp, class _Up>
242_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
243common_type_t<_Tp,_Up>
244lcm(_Tp __m, _Up __n)
245{
246    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
247    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to lcm cannot be bool" );
248    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to lcm cannot be bool" );
249    if (__m == 0 || __n == 0)
250        return 0;
251
252    using _Rp = common_type_t<_Tp,_Up>;
253    _Rp __val1 = __abs<_Tp>()(__m) / gcd(__m,__n);
254    _Up __val2 = __abs<_Up>()(__n);
255    _LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
256    return __val1 * __val2;
257}
258
259#endif /* _LIBCPP_STD_VER > 14 */
260
261_LIBCPP_END_NAMESPACE_STD
262
263#endif  // _LIBCPP_NUMERIC
264