/**
* @param \Traversable $iterator
*
* @return IGenerator
*/
public static function adapter(\Traversable $iterator)
{
if ($iterator instanceof IGenerator) {
return $iterator;
} elseif ($iterator instanceof IIterator) {
return new IIteratorAdapter($iterator);
} elseif ($iterator instanceof \ArrayIterator) {
return new ArrayIteratorAdapter($iterator);
} elseif ($iterator instanceof \IteratorAggregate) {
return static::adapter($iterator->getIterator());
} else {
return new IteratorAdapter($iterator);
}
}
/**
* @param array|\Traversable $xs
* @return \Iterator
* @throws \InvalidArgumentException
*/
public static function iterator($xs)
{
if ($xs instanceof \Iterator) {
return $xs;
} else {
if ($xs instanceof \IteratorAggregate) {
return $xs->getIterator();
} else {
if (is_array($xs)) {
return new \ArrayIterator($xs);
} else {
$t = gettype($xs);
throw new \InvalidArgumentException("'{$t}' object is not iterable");
}
}
}
}
/**
* @param \Traversable $x
* @param int $chunkSize
*/
public function __construct($x, $chunkSize)
{
if ($x instanceof \Iterator) {
$this->it = $x;
} else {
if ($x instanceof \IteratorAggregate) {
$this->it = $x->getIterator();
} else {
if (is_array($x)) {
$this->it = new \ArrayIterator($x);
} else {
$t = gettype($x);
throw new \InvalidArgumentException(sprintf('%s object is not iterable', $t));
}
}
}
if ($chunkSize < 1) {
throw new \InvalidArgumentException('chunkSize must be greater than 0');
}
$this->chunkSize = $chunkSize;
}
/**
* @param \Traversable $traversable
* @return array|\Traversable
*/
public static function copyTransversable($traversable)
{
// Allow for generators to be used once. Better than always throwing an error.
// Best to assume the user knows how to use Generators correctly,
// and might even be sending an empty iterator
if ($traversable instanceof \Generator) {
// We should NOT check the generator before it enters a foreach
// As with any PHP built in, observing it changes the outcome.
// Touching any method on an empty generator will cause a foreach to
// Throw rather than silently not iterating.
return $traversable;
}
return $traversable instanceof \IteratorAggregate ? $traversable->getIterator() : clone $traversable;
}
/**
* Just utils to convert any iterable to iterator object, used when slicing.
*
* @param \Traversable|array $iterable
*/
private function toIterator($iterable)
{
if ($iterable instanceof Iterator) {
return $iterable;
}
if ($iterable instanceof IteratorAggregate) {
return $iterable->getIterator();
}
if (is_array($iterable)) {
return new \ArrayIterator($iterable);
}
throw new \InvalidArgumentException('Argument must be iterable');
}
