Matrix multiplication

Cell.php

<?php

class Cell
{
    private $rowIndex;
    private $colIndex;

    public function __construct($rowIndex, $colIndex)
    {
        $this->rowIndex = $rowIndex;
        $this->colIndex = $colIndex;
    }

    public function getRowIndex()
    {
        return $this->rowIndex;
    }

    public function getColIndex()
    {
        return $this->colIndex;
    }

    public function getUpCell()
    {
        return new Cell($this->rowIndex - 1, $this->colIndex);
    }

    public function getDownCell()
    {
        return new Cell($this->rowIndex + 1, $this->colIndex);
    }

    public function getLeftCell()
    {
        return new Cell($this->rowIndex, $this->colIndex - 1);
    }

    public function getRightCell()
    {
        return new Cell($this->rowIndex, $this->colIndex + 1);
    }

    public function isSameTo(Cell $cell)
    {
        return $this->getRowIndex() === $cell->getRowIndex() && $this->getColIndex() === $cell->getColIndex();
    }
}

index.php

<?php

require 'Matrix.php';

$m1 = (new Matrix(2, 3))->load([
    1, 1, 1,
    1, 1, 1
]);

$m2 = (new Matrix(3, 2))->load([
    1, 1,
    1, 1,
    1, 1
]);

$result = $m1->mult($m2);

echo is_null($result) ? "MULT() Failed" : $result->print();

Matrix.php

<?php

class Matrix
{
    private $rows = 0;
    private $cols = 0;

    private $data = null;

    public function __construct($rows, $cols)
    {
        $this->rows = $rows;
        $this->cols = $cols;
    }

    public function load($data)
    {
        if (count($data) === $this->rows * $this->cols) {
            $this->data = $data;
        }
        else {
            $this->rows = 0;
            $this->cols = 0;
        }

        return $this;
    }

    public function index($i, $j)
    {
        $index = $this->cols * $i + $j;
        return isset($this->data[$index]) ? $this->data[$index] : null;
    }

    public function cell(Cell $cell)
    {
        return $this->index($cell->getRowIndex(), $cell->getColIndex());
    }

    public function mult(Matrix $m)
    {
        if ($this->cols !== $m->rows) {
            return null;
        }

        $result = new Matrix($this->rows, $m->cols);
        $data = [];

        for ($i = 0; $i < $this->rows; $i++) {
            for ($j = 0; $j < $m->cols; $j++) {
                $sum = 0;
                for ($k = 0; $k < $this->cols; $k++) {
                    $sum += $this->index($i, $k) * $m->index($j, $k);
                }
                $data[] = $sum;
            }
        }

        $result->load($data);

        return $result;
    }

    public function hasWayOut(Cell $from, Cell $to, Cell $prev = null)
    {
        if ($from->isSameTo($to)) {
            return true;
        }

        $case1 = $case2 = $case3 = $case4 = false;

        if (is_null($prev) || !$from->getUpCell()->isSameTo($prev) && $this->cell($from->getUpCell()) === 1) {
            $case1 = $this->hasWayOut($from->getUpCell(), $to, $from);
        }

        if (is_null($prev) || !$from->getDownCell()->isSameTo($prev) && $this->cell($from->getDownCell()) === 1) {
            $case2 = $this->hasWayOut($from->getDownCell(), $to, $from);
        }

        if (is_null($prev) || !$from->getLeftCell()->isSameTo($prev) && $this->cell($from->getLeftCell()) === 1) {
            $case3 = $this->hasWayOut($from->getLeftCell(), $to, $from);
        }

        if (is_null($prev) || !$from->getRightCell()->isSameTo($prev) && $this->cell($from->getRightCell()) === 1) {
            $case4 = $this->hasWayOut($from->getRightCell(), $to, $from);
        }

        return $case1 || $case2 || $case3 || $case4;
    }

    public function print()
    {
        $s = '';
        for ($i = 0; $i < $this->rows; $i++) {
            for ($j = 0; $j < $this->cols; $j++) {
                $s .= $this->index($i, $j) . ' ';
            }
            $s .= "\n";
        }
        return $s;
    }
}

path.php

<?php

require 'Cell.php';
require 'Matrix.php';

$path = (new Matrix(5, 5))->load([
    1, 1, 1, 1, 1,
    0, 1, 0, 0, 1,
    0, 1, 0, 0, 1,
    0, 1, 0, 0, 1,
    0, 0, 0, 0, 0
]);

$start = new Cell(0, 0);
$finish = new Cell(4, 4);

$wayOut = $path->hasWayOut($start, $finish);
var_dump($wayOut);