<?php


namespace App\Tables;

use App\Models\Row;

class RowNumerator
{
    /** @var int */
    private $next;
    /** @var int */
    private $last;

    /**
     * Create a numerator for the given number of rows.
     *
     * @param int $capacity
     */
    public function __construct($capacity)
    {
        list($this->next, $this->last) = Row::allocateRowIDs($capacity);
    }

    public function next()
    {
        if ($this->next > $this->last)
            throw new \OutOfBoundsException("Row numerator has run out of allocated GRID slots");

        return $this->next++;
    }
}