xref: /llvm-project-15.0.7/libcxx/include/numeric (revision 50d61da2)

// -*- C++ -*-
//===---------------------------- numeric ---------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//

#ifndef _LIBCPP_NUMERIC
#define _LIBCPP_NUMERIC

/*
    numeric synopsis

namespace std
{

template <class InputIterator, class T>
    T
    accumulate(InputIterator first, InputIterator last, T init);

template <class InputIterator, class T, class BinaryOperation>
    T
    accumulate(InputIterator first, InputIterator last, T init, BinaryOperation binary_op);

template <class InputIterator1, class InputIterator2, class T>
    T
    inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2, T init);

template <class InputIterator1, class InputIterator2, class T, class BinaryOperation1, class BinaryOperation2>
    T
    inner_product(InputIterator1 first1, InputIterator1 last1, InputIterator2 first2,
                  T init, BinaryOperation1 binary_op1, BinaryOperation2 binary_op2);

template <class InputIterator, class OutputIterator>
    OutputIterator
    partial_sum(InputIterator first, InputIterator last, OutputIterator result);

template <class InputIterator, class OutputIterator, class BinaryOperation>
    OutputIterator
    partial_sum(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op);

template <class InputIterator, class OutputIterator>
    OutputIterator
    adjacent_difference(InputIterator first, InputIterator last, OutputIterator result);

template <class InputIterator, class OutputIterator, class BinaryOperation>
    OutputIterator
    adjacent_difference(InputIterator first, InputIterator last, OutputIterator result, BinaryOperation binary_op);

template <class ForwardIterator, class T>
    void iota(ForwardIterator first, ForwardIterator last, T value);

template <class M, class N>
    constexpr common_type_t<M,N> gcd(M m, N n);    // C++17

template <class M, class N>
    constexpr common_type_t<M,N> lcm(M m, N n);    // C++17

}  // std

*/

#include <__config>
#include <iterator>
#include <limits> // for numeric_limits

#if !defined(_LIBCPP_HAS_NO_PRAGMA_SYSTEM_HEADER)
#pragma GCC system_header
#endif

_LIBCPP_BEGIN_NAMESPACE_STD

template <class _InputIterator, class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
accumulate(_InputIterator __first, _InputIterator __last, _Tp __init)
{
    for (; __first != __last; ++__first)
        __init = __init + *__first;
    return __init;
}

template <class _InputIterator, class _Tp, class _BinaryOperation>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
accumulate(_InputIterator __first, _InputIterator __last, _Tp __init, _BinaryOperation __binary_op)
{
    for (; __first != __last; ++__first)
        __init = __binary_op(__init, *__first);
    return __init;
}

template <class _InputIterator1, class _InputIterator2, class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2, _Tp __init)
{
    for (; __first1 != __last1; ++__first1, (void) ++__first2)
        __init = __init + *__first1 * *__first2;
    return __init;
}

template <class _InputIterator1, class _InputIterator2, class _Tp, class _BinaryOperation1, class _BinaryOperation2>
inline _LIBCPP_INLINE_VISIBILITY
_Tp
inner_product(_InputIterator1 __first1, _InputIterator1 __last1, _InputIterator2 __first2,
              _Tp __init, _BinaryOperation1 __binary_op1, _BinaryOperation2 __binary_op2)
{
    for (; __first1 != __last1; ++__first1, (void) ++__first2)
        __init = __binary_op1(__init, __binary_op2(*__first1, *__first2));
    return __init;
}

template <class _InputIterator, class _OutputIterator>
inline _LIBCPP_INLINE_VISIBILITY
_OutputIterator
partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
{
    if (__first != __last)
    {
        typename iterator_traits<_InputIterator>::value_type __t(*__first);
        *__result = __t;
        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
        {
            __t = __t + *__first;
            *__result = __t;
        }
    }
    return __result;
}

template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
inline _LIBCPP_INLINE_VISIBILITY
_OutputIterator
partial_sum(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
              _BinaryOperation __binary_op)
{
    if (__first != __last)
    {
        typename iterator_traits<_InputIterator>::value_type __t(*__first);
        *__result = __t;
        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
        {
            __t = __binary_op(__t, *__first);
            *__result = __t;
        }
    }
    return __result;
}

template <class _InputIterator, class _OutputIterator>
inline _LIBCPP_INLINE_VISIBILITY
_OutputIterator
adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result)
{
    if (__first != __last)
    {
        typename iterator_traits<_InputIterator>::value_type __t1(*__first);
        *__result = __t1;
        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
        {
            typename iterator_traits<_InputIterator>::value_type __t2(*__first);
            *__result = __t2 - __t1;
            __t1 = _VSTD::move(__t2);
        }
    }
    return __result;
}

template <class _InputIterator, class _OutputIterator, class _BinaryOperation>
inline _LIBCPP_INLINE_VISIBILITY
_OutputIterator
adjacent_difference(_InputIterator __first, _InputIterator __last, _OutputIterator __result,
                      _BinaryOperation __binary_op)
{
    if (__first != __last)
    {
        typename iterator_traits<_InputIterator>::value_type __t1(*__first);
        *__result = __t1;
        for (++__first, (void) ++__result; __first != __last; ++__first, (void) ++__result)
        {
            typename iterator_traits<_InputIterator>::value_type __t2(*__first);
            *__result = __binary_op(__t2, __t1);
            __t1 = _VSTD::move(__t2);
        }
    }
    return __result;
}

template <class _ForwardIterator, class _Tp>
inline _LIBCPP_INLINE_VISIBILITY
void
iota(_ForwardIterator __first, _ForwardIterator __last, _Tp __value_)
{
    for (; __first != __last; ++__first, (void) ++__value_)
        *__first = __value_;
}


#if _LIBCPP_STD_VER > 14
template <typename _Result, typename _Source, bool _IsSigned = is_signed<_Source>::value> struct __abs;

template <typename _Result, typename _Source>
struct __abs<_Result, _Source, true> {
    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
    _Result operator()(_Source __t) const noexcept
    {
    if (__t >= 0) return __t;
    if (__t == numeric_limits<_Source>::min()) return -static_cast<_Result>(__t);
    return -__t;
    }
};

template <typename _Result, typename _Source>
struct __abs<_Result, _Source, false> {
    _LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
    _Result operator()(_Source __t) const noexcept { return __t; }
};


template<class _Tp>
_LIBCPP_CONSTEXPR _LIBCPP_HIDDEN
_Tp __gcd(_Tp __m, _Tp __n)
{
    static_assert((!is_signed<_Tp>::value), "");
    return __n == 0 ? __m : _VSTD::__gcd<_Tp>(__n, __m % __n);
}


template<class _Tp, class _Up>
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
common_type_t<_Tp,_Up>
gcd(_Tp __m, _Up __n)
{
    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to gcd must be integer types");
    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to gcd cannot be bool" );
    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to gcd cannot be bool" );
    using _Rp = common_type_t<_Tp,_Up>;
    using _Wp = make_unsigned_t<_Rp>;
    return static_cast<_Rp>(_VSTD::__gcd(
        static_cast<_Wp>(__abs<_Rp, _Tp>()(__m)),
        static_cast<_Wp>(__abs<_Rp, _Up>()(__n))));
}

template<class _Tp, class _Up>
_LIBCPP_CONSTEXPR _LIBCPP_INLINE_VISIBILITY
common_type_t<_Tp,_Up>
lcm(_Tp __m, _Up __n)
{
    static_assert((is_integral<_Tp>::value && is_integral<_Up>::value), "Arguments to lcm must be integer types");
    static_assert((!is_same<typename remove_cv<_Tp>::type, bool>::value), "First argument to lcm cannot be bool" );
    static_assert((!is_same<typename remove_cv<_Up>::type, bool>::value), "Second argument to lcm cannot be bool" );
    if (__m == 0 || __n == 0)
        return 0;

    using _Rp = common_type_t<_Tp,_Up>;
    _Rp __val1 = __abs<_Rp, _Tp>()(__m) / _VSTD::gcd(__m, __n);
    _Rp __val2 = __abs<_Rp, _Up>()(__n);
    _LIBCPP_ASSERT((numeric_limits<_Rp>::max() / __val1 > __val2), "Overflow in lcm");
    return __val1 * __val2;
}

#endif /* _LIBCPP_STD_VER > 14 */

_LIBCPP_END_NAMESPACE_STD

#endif  // _LIBCPP_NUMERIC