multipleiterator.inc

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<?php
class MultipleIterator implements Iterator
{
    private $iterators;

    private $flags;

    const MIT_NEED_ANY = 0;

    const MIT_NEED_ALL  = 1;

    const MIT_KEYS_NUMERIC  = 0;

    const MIT_KEYS_ASSOC  = 2;

    public function __construct($flags = self::MIT_NEED_ALL|self::MIT_KEYS_NUMERIC)
    {
        $this->iterators = new SplObjectStorage();
        $this->flags = $flags;
    }

    public function getFlags()
    {
        return $this->flags;
    }

    public function setFlags($flags)
    {
        $this->flags = $flags;
    }

    public function attachIterator(Iterator $iter, $inf = NULL)
    {

        if (!is_null($inf))
        {
            if (!is_int($inf) && !is_string($inf))
            {
                throw new IllegalValueException('Inf must be NULL, integer or string');
            }
            foreach($this->iterators as $iter)
            {
                if ($inf == $this->iterators->getInfo())
                {
                    throw new IllegalValueException('Key duplication error');
                }
            }
        }
        $this->iterators->attach($iter, $inf);
    }

    public function detachIterator(Iterator $iter)
    {
        $this->iterators->detach($iter);
    }

    public function containsIterator(Iterator $iter)
    {
        return $this->iterator->contains($iter);
    }

    public function countIterators()
    {
        return $this->iterators->count();
    }

    public function rewind()
    {
        foreach($this->iterators as $iter)
        {
            $iter->rewind();
        }
    }

    public function valid()
    {
        if (!sizeof($this->iterators)) {
            return false;
        }
        // The following code is an optimized version that executes as few
        // valid() calls as necessary and that only checks the flags once.
        $expect = $this->flags & self::MIT_NEED_ALL ? true : false;
        foreach($this->iterators as $iter)
        {
            if ($expect != $iter->valid())
            {
                return !$expect;
            }
        }
        return $expect;
    }

    public function next()
    {
        foreach($this->iterators as $iter)
        {
            $iter->next();
        }
    }

    public function current()
    {
        if (!sizeof($this->iterators))
        {
            return false;
        }
        $retval = array();
        foreach($this->iterators as $iter)
        {
            if ($iter->valid())
            {
                if ($this->flags & self::MIT_KEYS_ASSOC)
                {
                    $key = $this->iterators->getInfo();
                    if (is_null($key))
                    {
                        throw new IllegalValueException('Sub-Iterator is associated with NULL');
                    }
                    $retval[$key] = $iter->current();
                }
                else
                {
                    $retval[] = $iter->current();
                }
            }
            else if ($this->flags & self::MIT_NEED_ALL)
            {
                throw new RuntimeException('Called current() with non valid sub iterator');
            }
            else
            {
                $retval[] = NULL;
            }
        }
        return $retval;
    }

    public function key()
    {
        if (!sizeof($this->iterators))
        {
            return false;
        }
        $retval = array();
        foreach($this->iterators as $iter)
        {
            if ($iter->valid())
            {
                $retval[] = $iter->key();
            }
            else if ($this->flags & self::MIT_NEED_ALL)
            {
                throw new LogicException('Called key() with non valid sub iterator');
            }
            else
            {
                $retval[] = NULL;
            }
        }
        return $retval;
    }
}