/**
* Returns an unsigned integer from the bit level
*
* @param \PhpBinaryReader\BinaryReader $br
* @param int $length
* @throws \OutOfBoundsException
* @throws InvalidDataException
* @return int
*/
public function read(BinaryReader &$br, $length)
{
if (!is_int($length)) {
throw new InvalidDataException('The length parameter must be an integer');
}
$bitmask = new BitMask();
$result = 0;
$bits = $length;
$shift = $br->getCurrentBit();
if ($shift != 0) {
$bitsLeft = 8 - $shift;
if ($bitsLeft < $bits) {
$bits -= $bitsLeft;
$result = $br->getNextByte() >> $shift << $bits;
} elseif ($bitsLeft > $bits) {
$br->setCurrentBit($br->getCurrentBit() + $bits);
return $br->getNextByte() >> $shift & $bitmask->getMask($bits, BitMask::MASK_LO);
} else {
$br->setCurrentBit(0);
return $br->getNextByte() >> $shift;
}
}
if (!$br->canReadBytes($length / 8)) {
throw new \OutOfBoundsException('Cannot read bits, it exceeds the boundary of the file');
}
if ($bits >= 8) {
$bytes = intval($bits / 8);
if ($bytes == 1) {
$bits -= 8;
$result |= ($this->getSigned() ? $br->readInt8() : $br->readUInt8()) << $bits;
} elseif ($bytes == 2) {
$bits -= 16;
$result |= ($this->getSigned() ? $br->readInt16() : $br->readUInt16()) << $bits;
} elseif ($bytes == 4) {
$bits -= 32;
$result |= ($this->getSigned() ? $br->readInt32() : $br->readUInt32()) << $bits;
} else {
while ($bits > 8) {
$bits -= 8;
$result |= ($this->getSigned() ? $br->readInt8() : $br->readUInt8()) << 8;
}
}
}
if ($bits != 0) {
$code = $this->getSigned() ? 'c' : 'C';
$data = unpack($code, $br->readFromHandle(1));
$br->setNextByte($data[1]);
$result |= $br->getNextByte() & $bitmask->getMask($bits, BitMask::MASK_LO);
}
$br->setCurrentBit($bits);
return $result;
}