function hashCode($s)
{
$h = 0;
$len = strlen($s);
for ($i = 0; $i < $len; $i++) {
$h = overflow32(31 * $h + ord($s[$i]));
}
return $h;
}
/**
* Efficient method to check if a range of bits is set, or not set.
*
* @param start start of range, inclusive.
* @param end end of range, exclusive
* @param value if true, checks that bits in range are set, otherwise checks that they are not set
* @return true iff all bits are set or not set in range, according to value argument
* @throws InvalidArgumentException if end is less than or equal to start
*/
public function isRange($start, $end, $value)
{
if ($end < $start) {
throw new InvalidArgumentException();
}
if ($end == $start) {
return true;
// empty range matches
}
$end--;
// will be easier to treat this as the last actually set bit -- inclusive
$firstInt = intval($start / 32);
$lastInt = intval($end / 32);
for ($i = $firstInt; $i <= $lastInt; $i++) {
$firstBit = $i > $firstInt ? 0 : $start & 0x1f;
$lastBit = $i < $lastInt ? 31 : $end & 0x1f;
$mask = 0;
if ($firstBit == 0 && $lastBit == 31) {
$mask = -1;
} else {
$mask = 0;
for ($j = $firstBit; $j <= $lastBit; $j++) {
$mask = overflow32($mask | 1 << $j);
}
}
// Return false if we're looking for 1s and the masked bits[i] isn't all 1s (that is,
// equals the mask, or we're looking for 0s and the masked portion is not all 0s
if (($this->bits[$i] & $mask) != ($value ? $mask : 0)) {
return false;
}
}
return true;
}
/**
* <p>Sets a square region of the bit matrix to true.</p>
*
* @param $left; The horizontal position to begin at (inclusive)
* @param $top; The vertical position to begin at (inclusive)
* @param $width; The width of the region
* @param $height; The height of the region
*/
public function setRegion($left, $top, $width, $height)
{
if ($top < 0 || $left < 0) {
throw new InvalidArgumentException("Left and top must be nonnegative");
}
if ($height < 1 || $width < 1) {
throw new InvalidArgumentException("Height and width must be at least 1");
}
$right = $left + $width;
$bottom = $top + $height;
if ($bottom > $this->height || $right > $this->width) {
//> this.height || right > this.width
throw new InvalidArgumentException("The region must fit inside the matrix");
}
for ($y = $top; $y < $bottom; $y++) {
$offset = $y * $this->rowSize;
for ($x = $left; $x < $right; $x++) {
$this->bits[$offset + intval($x / 32)] = overflow32($this->bits[$offset + intval($x / 32)] |= 1 << ($x & 0x1f));
}
}
}
