dualiterator.inc

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<?php

class DualIterator implements Iterator
{
    const CURRENT_LHS   = 0x01;
    const CURRENT_RHS   = 0x02;
    const CURRENT_ARRAY = 0x03;
    const CURRENT_0     = 0x00;

    const KEY_LHS   = 0x10;
    const KEY_RHS   = 0x20;
    const KEY_0     = 0x00;
    
    const DEFAULT_FLAGS = 0x13;
    
    private $lhs;
    private $rhs;
    private $flags;

    function __construct(Iterator $lhs, Iterator $rhs, 
                    $flags = 0x13 /*DualIterator::DEFAULT_FLAGS*/)
    {
        $this->lhs   = $lhs;
        $this->rhs   = $rhs;
        $this->flags = $flags;
    }

    function getLHS()
    {
        return $this->lhs;
    }

    function getRHS()
    {
        return $this->rhs;
    }

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

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

    function rewind()
    {
        $this->lhs->rewind();
        $this->rhs->rewind();   
    }

    function valid()
    {
        return $this->lhs->valid() && $this->rhs->valid();  
    }

    function current()
    {
        switch($this->flags & 0x0F)
        {
        default:
        case self::CURRENT_ARRAY:
            return array($this->lhs->current(), $this->rhs->current());
        case self::CURRENT_LHS:
            return $this->lhs->current();
        case self::CURRENT_RHS:
            return $this->rhs->current();
        case self::CURRENT_0:
            return NULL;
        }
    }

    function key()
    {
        switch($this->flags & 0xF0)
        {
        default:
        case self::KEY_LHS:
            return $this->lhs->key();
        case self::KEY_RHS:
            return $this->rhs->key();
        case self::KEY_0:
            return NULL;
        }
    }

    function next()
    {
        $this->lhs->next();
        $this->rhs->next();
    }

    function areIdentical()
    {
        return $this->valid()
             ? $this->lhs->current() === $this->rhs->current()
            && $this->lhs->key()     === $this->rhs->key()
             : $this->lhs->valid()   ==  $this->rhs->valid();
    }

    function areEqual()
    {
        return $this->valid()
             ? $this->lhs->current() ==  $this->rhs->current()
            && $this->lhs->key()     ==  $this->rhs->key()
             : $this->lhs->valid()   ==  $this->rhs->valid();
    }

    static function compareIterators(Iterator $lhs, Iterator $rhs, 
                                     $identical = false)
    {
        if ($lhs instanceof RecursiveIterator)
        {
            if ($rhs instanceof RecursiveIterator)
            {
                $it = new RecursiveDualIterator($lhs, $rhs, 
                                self::CURRENT_0 | self::KEY_0);
                $it = new RecursiveCompareDualIterator($it);
            }
            else
            {
                return false;
            }
        }
        else
        {
            $it = new DualIterator($lhs, $rhs, self::CURRENT_0 | self::KEY_0);
        }

        if ($identical)
        {
            foreach($it as $n)
            {
                if (!$it->areIdentical())
                {
                    return false;
                }
            }
        }
        else
        {
            foreach($it as $n)
            {
                if (!$it->areEqual())
                {
                    return false;
                }
            }
        }
        return $identical ? $it->areIdentical() : $it->areEqual();
    }
}

?>