<?php

/**
 * Validates an integer.
 * @note While this class was modeled off the CSS definition, no currently
 *       allowed CSS uses this type.  The properties that do are: widows,
 *       orphans, z-index, counter-increment, counter-reset.  Some of the
 *       HTML attributes, however, find use for a non-negative version of this.
 */
class HTMLPurifier_AttrDef_Integer extends HTMLPurifier_AttrDef
{

    /**
     * Bool indicating whether or not negative values are allowed
     */
    protected $negative = true;

    /**
     * Bool indicating whether or not zero is allowed
     */
    protected $zero = true;

    /**
     * Bool indicating whether or not positive values are allowed
     */
    protected $positive = true;

    /**
     * @param $negative Bool indicating whether or not negative values are allowed
     * @param $zero Bool indicating whether or not zero is allowed
     * @param $positive Bool indicating whether or not positive values are allowed
     */
    public function __construct(
        $negative = true, $zero = true, $positive = true
    ) {
        $this->negative = $negative;
        $this->zero     = $zero;
        $this->positive = $positive;
    }

    public function validate($integer, $config, $context) {

        $integer = $this->parseCDATA($integer);
        if ($integer === '') return false;

        // we could possibly simply typecast it to integer, but there are
        // certain fringe cases that must not return an integer.

        // clip leading sign
        if ( $this->negative && $integer[0] === '-' ) {
            $digits = substr($integer, 1);
            if ($digits === '0') $integer = '0'; // rm minus sign for zero
        } elseif( $this->positive && $integer[0] === '+' ) {
            $digits = $integer = substr($integer, 1); // rm unnecessary plus
        } else {
            $digits = $integer;
        }

        // test if it's numeric
        if (!ctype_digit($digits)) return false;

        // perform scope tests
        if (!$this->zero     && $integer == 0) return false;
        if (!$this->positive && $integer > 0) return false;
        if (!$this->negative && $integer < 0) return false;

        return $integer;

    }

}

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