/**
* Return a signed byte from the data.
*
* @param
* int the offset into the data. An offset of zero will
* return the first byte in the current allowed window. The last
* valid offset is equal to {@link getSize()}-1. Invalid offsets
* will result in a {@link PelDataWindowOffsetException} being
* thrown.
*
* @return int the signed byte found at offset.
*/
public function getSByte($o = 0)
{
/*
* Validate the offset --- this throws an exception if offset is
* out of range.
*/
$this->validateOffset($o);
/* Translate the offset into an offset into the data. */
$o += $this->start;
/* Return a signed byte. */
return PelConvert::bytesToSByte($this->data, $o);
}
function testSByte()
{
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 0), 0);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 1), 0);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 2), 0);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 3), 0);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 4), 1);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 5), 35);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 6), 69);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 7), 103);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 8), -119);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 9), -85);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 10), -51);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 11), -17);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 12), -1);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 13), -1);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 14), -1);
$this->assertEqual(PelConvert::bytesToSByte($this->bytes, 15), -1);
}