public unsafe int LastIndexOf(char value, int startIndex, int count)
{
if (Length == 0)
{
return(-1);
}
if ((uint)startIndex >= (uint)Length)
{
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.startIndex, ExceptionResource.ArgumentOutOfRange_IndexMustBeLess);
}
if ((uint)count > (uint)startIndex + 1)
{
ThrowHelper.ThrowArgumentOutOfRangeException(ExceptionArgument.count, ExceptionResource.ArgumentOutOfRange_Count);
}
int startSearchAt = startIndex + 1 - count;
int result = SpanHelpers.LastIndexOfValueType(ref Unsafe.As <char, short>(ref Unsafe.Add(ref _firstChar, startSearchAt)), (short)value, count);
return(result < 0 ? result : result + startSearchAt);
}
// Returns the index of the last occurrence of a specified character in the current instance. // The search starts at startIndex and runs backwards to startIndex - count + 1. // The character at position startIndex is included in the search. startIndex is the larger // index within the string. public int LastIndexOf(char value) => SpanHelpers.LastIndexOfValueType(ref Unsafe.As <char, short>(ref _firstChar), (short)value, Length);