Zabbix

<?php declare(strict_types = 1);

/*

** Zabbix

** Copyright (C) 2001-2022 Zabbix SIA

**

** This program is free software; you can redistribute it and/or modify

** it under the terms of the GNU General Public License as published by

** the Free Software Foundation; either version 2 of the License, or

** (at your option) any later version.

**

** This program is distributed in the hope that it will be useful,

** but WITHOUT ANY WARRANTY; without even the implied warranty of

** MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the

** GNU General Public License for more details.

**

** You should have received a copy of the GNU General Public License

** along with this program; if not, write to the Free Software

** Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.

**/

​

​

class CExpressionParser extends CParser {

​

    // For parsing of expressions.

    private const STATE_AFTER_OPEN_BRACE = 1;

    private const STATE_AFTER_BINARY_OPERATOR = 2;

    private const STATE_AFTER_LOGICAL_OPERATOR = 3;

    private const STATE_AFTER_NOT_OPERATOR = 4;

    private const STATE_AFTER_UNARY_MINUS = 5;

    private const STATE_AFTER_CLOSE_BRACE = 6;

    private const STATE_AFTER_CONSTANT = 7;

​

    // For parsing of math function parameters.

    private const STATE_NEW = 1;

    private const STATE_END = 2;

    private const STATE_END_OF_PARAMS = 3;

​

    private const MAX_MATH_FUNCTION_DEPTH = 32;

​

    /**

     * An error message if trigger expression is not valid

     *

     * @var string

     */

    private $error = '';

​

    /**

     * An options array.

     *

     * Supported options:

     *   'usermacros' => false            Enable user macros usage in expression.

     *   'lldmacros' => false             Enable low-level discovery macros usage in expression.

     *   'collapsed_expression' => false  Short trigger expression.

     *                                       For example: {439} > {$MAX_THRESHOLD} or {439} < {$MIN_THRESHOLD}

     *   'calculated' => false            Parse calculated item formula instead of trigger expression.

     *   'host_macro' => false            Allow {HOST.HOST} macro as host name part in the query.

     *   'host_macro_n' => false          Allow {HOST.HOST} and {HOST.HOST<1-9>} macros as host name part in the query.

     *   'empty_host' => false            Allow empty hostname in the query string.

     *

     * @var array

     */

    private $options = [

        'usermacros' => false,