/// <summary> The number of true elements in a boolean sequence. </summary>
public static int CountTrue <TIn, TProducer>(
this SpanEnumerable <TIn, bool, TProducer> spanEnum)
where TProducer : struct, IProducer <TIn, bool>
{
var count = 0;
long longOnStack = default;
Span <bool> onStack =
MemoryMarshal.Cast <long, bool>(
MemoryMarshal.CreateSpan(ref longOnStack, 1));
while (true)
{
onStack = spanEnum.ConsumeInto(onStack);
if (onStack.Length == 0)
{
break;
}
count += onStack.CountTrue();
}
return(count);
}
/// <summary>
/// Takes enough values from the sequence to fill the provided span.
/// </summary>
/// <remarks>
/// A copy of the enumerable is taken, which means that (beyond any
/// side-effects of consuming values from it) the original
/// enumerable is unchanged.
/// </remarks>
/// <returns>
/// Returns the span, maybe resized if there were not enough values
/// in the enumerable.
/// </returns>
public static Span <TOut> TakeInto <TOut>(
this SpanEnumerable <TOut> self,
Span <TOut> output)
=>
self.ConsumeInto(output);