File: /var/www/delta/wp-content/plugins/contact-form-7/includes/swv/php/rules/stepnumber.php
<?php
namespace Contactable\SWV;
class StepNumberRule extends Rule {
	const rule_name = 'stepnumber';
	public function matches( $context ) {
		if ( false === parent::matches( $context ) ) {
			return false;
		}
		if ( empty( $context['text'] ) ) {
			return false;
		}
		return true;
	}
	public function validate( $context ) {
		$input = $this->get_default_input();
		$input = wpcf7_array_flatten( $input );
		$input = wpcf7_strip_whitespaces( $input );
		$input = wpcf7_exclude_blank( $input );
		$base = floatval( $this->get_property( 'base' ) );
		$interval = floatval( $this->get_property( 'interval' ) );
		if ( ! ( 0 < $interval ) ) {
			return true;
		}
		foreach ( $input as $i ) {
			$remainder = fmod( floatval( $i ) - $base, $interval );
			if (
				0.0 === round( abs( $remainder ), 6 ) or
				0.0 === round( abs( $remainder - $interval ), 6 )
			) {
				continue;
			}
			return $this->create_error();
		}
		return true;
	}
}