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Added specialisations of etl::rotate for different iterator types

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This commit is contained in:
John Wellbelove 2024-05-13 10:56:54 +01:00
parent 8528ed2b80
commit 4f64c83a47
1 changed files with 55 additions and 2 deletions
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57
include/etl/algorithm.h
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@ -1157,6 +1157,7 @@ namespace etl
//***************************************************************************
namespace private_algorithm
{
#if ETL_USING_CPP11
//*********************************
// For random access iterators
template <typename TIterator>
@ -1169,15 +1170,17 @@ namespace etl
return first;
}
typedef typename etl::iterator_traits<TIterator>::value_type value_type;
int n = last - first;
int m = middle - first;
int gcd_nm = etl::gcd(n, m);
int gcd_nm = (n == 0 || m == 0) ? n + m : etl::gcd(n, m);
TIterator result = first + (last - middle);
for (int i = 0; i < gcd_nm; i++)
{
auto temp = *(first + i);
value_type temp = etl::move(*(first + i));
int j = i;
while (true)
@ -1194,6 +1197,55 @@ namespace etl
break;
}
*(first + j) = etl::move(*(first + k));
j = k;
}
*(first + j) = etl::move(temp);
}
return result;
}
#else
//*********************************
// For random access iterators
template <typename TIterator>
ETL_CONSTEXPR14
typename etl::enable_if<etl::is_random_access_iterator<TIterator>::value, TIterator>::type
rotate_general(TIterator first, TIterator middle, TIterator last)
{
if (first == middle || middle == last)
{
return first;
}
typedef typename etl::iterator_traits<TIterator>::value_type value_type;
int n = last - first;
int m = middle - first;
int gcd_nm = (n == 0 || m == 0) ? n + m : etl::gcd(n, m);
TIterator result = first + (last - middle);
for (int i = 0; i < gcd_nm; i++)
{
value_type temp = *(first + i);
int j = i;
while (true)
{
int k = j + m;
if (k >= n)
{
k = k - n;
}
if (k == i)
{
break;
}
*(first + j) = *(first + k);
j = k;
}
@ -1203,6 +1255,7 @@ namespace etl
return result;
}
#endif
//*********************************
// For bidirectional iterators