static TSum SumNullable <TSource, TSum>(this ReadOnlySpan <TSource> source)
where TSum : struct
{
var sum = default(TSum);
foreach (var item in source)
{
sum = GenericsOperator.Sum(item, sum);
}
return(sum);
}
internal static TSum Sum <TEnumerable, TEnumerator, TSource, TSum>(this TEnumerable source)
where TEnumerable : IValueEnumerable <TSource, TEnumerator>
where TEnumerator : struct, IEnumerator <TSource>
where TSum : struct
{
var sum = default(TSum);
using var enumerator = source.GetEnumerator();
while (enumerator.MoveNext())
{
sum = GenericsOperator.Sum(enumerator.Current, sum);
}
return(sum);
}
static TSum SumRef <TSource, TSum, TPredicate>(this ReadOnlySpan <TSource> source, TPredicate predicate)
where TPredicate : struct, IFunctionIn <TSource, bool>
where TSum : struct
{
var sum = default(TSum);
foreach (ref readonly var item in source)
{
if (predicate.Invoke(in item))
{
sum = GenericsOperator.Sum(item, sum);
}
}
return(sum);
}
static TSum SumAt <TSource, TSum, TPredicate>(this ReadOnlySpan <TSource> source, TPredicate predicate)
where TPredicate : struct, IFunction <TSource, int, bool>
where TSum : struct
{
var sum = default(TSum);
for (var index = 0; index < source.Length; index++)
{
var item = source[index];
if (predicate.Invoke(item, index))
{
sum = GenericsOperator.Sum(item, sum);
}
}
return(sum);
}
static TSum SumAt <TEnumerable, TEnumerator, TSource, TResult, TSum, TSelector>(this TEnumerable source, TSelector selector)
where TEnumerable : IValueEnumerable <TSource, TEnumerator>
where TEnumerator : struct, IEnumerator <TSource>
where TSelector : struct, IFunction <TSource, int, TResult>
where TSum : struct
{
var sum = default(TSum);
using var enumerator = source.GetEnumerator();
for (var index = 0; enumerator.MoveNext(); index++)
{
var item = enumerator.Current;
sum = GenericsOperator.Sum(selector.Invoke(item, index), sum);
}
return(sum);
}
internal static TSum SumAtRef <TEnumerable, TEnumerator, TSource, TSum, TPredicate>(this TEnumerable source, TPredicate predicate)
where TEnumerable : IValueEnumerable <TSource, TEnumerator>
where TEnumerator : struct, IEnumerator <TSource>
where TPredicate : struct, IFunctionIn <TSource, int, bool>
where TSum : struct
{
var sum = default(TSum);
using var enumerator = source.GetEnumerator();
for (var index = 0; enumerator.MoveNext(); index++)
{
var item = enumerator.Current;
if (predicate.Invoke(in item, index))
{
sum = GenericsOperator.Sum(item, sum);
}
}
return(sum);
}
internal static TSum Sum <TEnumerable, TEnumerator, TSource, TResult, TSum, TPredicate, TSelector>(this TEnumerable source, TPredicate predicate, TSelector selector)
where TEnumerable : IValueEnumerable <TSource, TEnumerator>
where TEnumerator : struct, IEnumerator <TSource>
where TPredicate : struct, IFunction <TSource, bool>
where TSelector : struct, IFunction <TSource, TResult>
where TSum : struct
{
var sum = default(TSum);
using var enumerator = source.GetEnumerator();
while (enumerator.MoveNext())
{
var item = enumerator.Current;
if (predicate.Invoke(item))
{
sum = GenericsOperator.Sum(selector.Invoke(item), sum);
}
}
return(sum);
}