private Span Read(
int tag)
{
Span span = Unsafe.Add(ref _stack0, _depth);
ReadOnlySpan <byte> bytes = span.ApplyTo(_buffer);
if (_failed || bytes.Length < 2 || bytes[0] != tag)
{
goto failed;
}
int start = 2;
int length = 0;
if ((bytes[1] & ~0x7F) == 0)
{
length = bytes[1];
}
else
{
int count = bytes[1] & 0x7F;
if (count < 1 || count > sizeof(int) || count > bytes.Length - 2 || bytes[2] == 0)
{
goto failed;
}
while (count-- > 0)
{
length = (length << 8) | bytes[start++];
}
if (length < 0x80)
{
goto failed;
}
}
if (length > bytes.Length - start)
{
goto failed;
}
Unsafe.Add(ref _stack0, _depth) = span.Slice(start + length);
return(span.Slice(start, length));
failed:
Fail();
return(default);