xref: /freebsd-12.1/contrib/libc++/include/numeric (revision f9448bf3)
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#include <limits> // for numeric_limits
69
70#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
71#pragma GCC system_header
72#endif
73
74_LIBCPP_PUSH_MACROS
75#include <__undef_macros>
76
77_LIBCPP_BEGIN_NAMESPACE_STD
78
79template <class _InputIterator, class _Tp>
80inline _LIBCPP_INLINE_VISIBILITY
81_Tp
82accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
83{
84    for (; __first != __last; ++__first)
85        __init = __init + *__first;
86    return __init;
87}
88
89template <class _InputIterator, class _Tp, class _BinaryOperation>
90inline _LIBCPP_INLINE_VISIBILITY
91_Tp
92accumulate(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOperation __binary_op)
93{
94    for (; __first != __last; ++__first)
95        __init = __binary_op(__init, *__first);
96    return __init;
97}
98
99template <class _InputIterator1, class _InputIterator2, class _Tp>
100inline _LIBCPP_INLINE_VISIBILITY
101_Tp
102inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _Tp __init)
103{
104    for (; __first1 != __last1; ++__first1, (void) ++__first2)
105        __init = __init + *__first1 * *__first2;
106    return __init;
107}
108
109template <class _InputIterator1, class _InputIterator2, class _Tp, class _BinaryOperation1, class _BinaryOperation2>
110inline _LIBCPP_INLINE_VISIBILITY
111_Tp
112inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
113              _Tp __init, _BinaryOperation1 __binary_op1, _BinaryOperation2 __binary_op2)
114{
115    for (; __first1 != __last1; ++__first1, (void) ++__first2)
116        __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
117    return __init;
118}
119
120template <class _InputIterator, class _OutputIterator>
121inline _LIBCPP_INLINE_VISIBILITY
122_OutputIterator
123partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
124{
125    if (__first != __last)
126    {
127        typename iterator_traits<_InputIterator>::value_type __t(*__first);
128        *__result = __t;
129        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
130        {
131            __t = __t + *__first;
132            *__result = __t;
133        }
134    }
135    return __result;
136}
137
138template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
139inline _LIBCPP_INLINE_VISIBILITY
140_OutputIterator
141partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
142              _BinaryOperation __binary_op)
143{
144    if (__first != __last)
145    {
146        typename iterator_traits<_InputIterator>::value_type __t(*__first);
147        *__result = __t;
148        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
149        {
150            __t = __binary_op(__t, *__first);
151            *__result = __t;
152        }
153    }
154    return __result;
155}
156
157template <class _InputIterator, class _OutputIterator>
158inline _LIBCPP_INLINE_VISIBILITY
159_OutputIterator
160adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
161{
162    if (__first != __last)
163    {
164        typename iterator_traits<_InputIterator>::value_type __t1(*__first);
165        *__result = __t1;
166        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
167        {
168            typename iterator_traits<_InputIterator>::value_type __t2(*__first);
169            *__result = __t2 - __t1;
170            __t1 = _VSTD::move(__t2);
171        }
172    }
173    return __result;
174}
175
176template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
177inline _LIBCPP_INLINE_VISIBILITY
178_OutputIterator
179adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
180                      _BinaryOperation __binary_op)
181{
182    if (__first != __last)
183    {
184        typename iterator_traits<_InputIterator>::value_type __t1(*__first);
185        *__result = __t1;
186        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
187        {
188            typename iterator_traits<_InputIterator>::value_type __t2(*__first);
189            *__result = __binary_op(__t2, __t1);
190            __t1 = _VSTD::move(__t2);
191        }
192    }
193    return __result;
194}
195
196template <class _ForwardIterator, class _Tp>
197inline _LIBCPP_INLINE_VISIBILITY
198void
199iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value_)
200{
201    for (; __first != __last; ++__first, (void) ++__value_)
202        *__first = __value_;
203}
204
205
206#if _LIBCPP_STD_VER > 14
207template <typename _Result, typename _Source, bool _IsSigned = is_signed<_Source>::value> struct __abs;
208
209template <typename _Result, typename _Source>
210struct __abs<_Result, _Source, true> {
211    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
212    _Result operator()(_Source __t) const noexcept
213    {
214    if (__t >= 0) return __t;
215    if (__t == numeric_limits<_Source>::min()) return -static_cast<_Result>(__t);
216    return -__t;
217    }
218};
219
220template <typename _Result, typename _Source>
221struct __abs<_Result, _Source, false> {
222    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
223    _Result operator()(_Source __t) const noexcept { return __t; }
224};
225
226
227template<class _Tp>
228_LIBCPP_CONSTEXPR _LIBCPP_HIDDEN
229_Tp __gcd(_Tp __m, _Tp __n)
230{
231    static_assert((!is_signed<_Tp>::value), "");
232    return __n == 0 ? __m : _VSTD::__gcd<_Tp>(__n, __m % __n);
233}
234
235
236template<class _Tp, class _Up>
237_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
238common_type_t<_Tp,_Up>
239gcd(_Tp __m, _Up __n)
240{
241    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
242    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to gcd cannot be bool" );
243    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to gcd cannot be bool" );
244    using _Rp = common_type_t<_Tp,_Up>;
245    using _Wp = make_unsigned_t<_Rp>;
246    return static_cast<_Rp>(_VSTD::__gcd(
247        static_cast<_Wp>(__abs<_Rp, _Tp>()(__m)),
248        static_cast<_Wp>(__abs<_Rp, _Up>()(__n))));
249}
250
251template<class _Tp, class _Up>
252_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
253common_type_t<_Tp,_Up>
254lcm(_Tp __m, _Up __n)
255{
256    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
257    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to lcm cannot be bool" );
258    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to lcm cannot be bool" );
259    if (__m == 0 || __n == 0)
260        return 0;
261
262    using _Rp = common_type_t<_Tp,_Up>;
263    _Rp __val1 = __abs<_Rp, _Tp>()(__m) / _VSTD::gcd(__m, __n);
264    _Rp __val2 = __abs<_Rp, _Up>()(__n);
265    _LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
266    return __val1 * __val2;
267}
268
269#endif /* _LIBCPP_STD_VER > 14 */
270
271_LIBCPP_END_NAMESPACE_STD
272
273_LIBCPP_POP_MACROS
274
275#endif  // _LIBCPP_NUMERIC
276