public int Seek(int char0, int char1)
{
if (IsDefault)
{
return -1;
}
var byte0 = (byte)char0;
var byte1 = (byte)char1;
var vectorStride = Vector<byte>.Count;
var ch0Vector = new Vector<byte>(byte0);
var ch1Vector = new Vector<byte>(byte1);
var block = _block;
var index = _index;
var array = block.Array;
while (true)
{
while (block.End == index)
{
if (block.Next == null)
{
_block = block;
_index = index;
return -1;
}
block = block.Next;
index = block.Start;
array = block.Array;
}
while (block.End != index)
{
var following = block.End - index;
if (following >= vectorStride)
{
var data = new Vector<byte>(array, index);
var ch0Equals = Vector.Equals(data, ch0Vector);
var ch0Count = Vector.Dot(ch0Equals, _dotCount);
var ch1Equals = Vector.Equals(data, ch1Vector);
var ch1Count = Vector.Dot(ch1Equals, _dotCount);
if (ch0Count == 0 && ch1Count == 0)
{
index += vectorStride;
continue;
}
else if (ch0Count < 2 && ch1Count < 2)
{
var ch0Index = ch0Count == 1 ? Vector.Dot(ch0Equals, _dotIndex) : byte.MaxValue;
var ch1Index = ch1Count == 1 ? Vector.Dot(ch1Equals, _dotIndex) : byte.MaxValue;
if (ch0Index < ch1Index)
{
_block = block;
_index = index + ch0Index;
return char0;
}
else
{
_block = block;
_index = index + ch1Index;
return char1;
}
}
else
{
following = vectorStride;
}
}
while (following > 0)
{
var byteIndex = block.Array[index];
if (byteIndex == byte0)
{
_block = block;
_index = index;
return char0;
}
else if (byteIndex == byte1)
{
_block = block;
_index = index;
return char1;
}
following--;
index++;
}
}
}
}