public void Setup()
{
var array = Enumerable.Range(0, 1000).ToArray();
_data = new ListLike <int> {
Array = array, Length = 500
};
}
static EnumerationTest()
{
var array = Enumerable.Range(0, 1000).ToArray();
_data = new ListLike <int> {
Array = array, Length = 500
};
_expected = array.Take(500).Sum();
}
public static int SumArray(ListLike <int> list)
{
var sum = 0;
var(array, length) = (list.Array, list.Length);
for (int i = 0; i < length; i++)
{
sum += array[i];
}
return(sum);
}
public static int SumSpan(ListLike <int> list)
{
// Fast Span (.NET Core 2.1 以降限定)だけど、foreach で普通に生列挙と同じスピードが出るのが Span のいいところ。
var sum = 0;
foreach (var x in list.GetSpan())
{
sum += x;
}
return(sum);
}
public static int SumEnumerable(ListLike <int> list)
{
var sum = 0;
// foreach (var x in list) で行けるんだけど、比較のために生利用
var e = list.GetEnumerator();
while (e.MoveNext())
{
sum += e.Current;
}
return(sum);
}
public static int SumFastEnumerable(ListLike <int> list)
{
var sum = 0;
var e = list.GetFastEnumerator();
var x = e.TryMoveNext(out var success);
while (success)
{
sum += x;
x = e.TryMoveNext(out success);
}
return(sum);
}
