<?php
/**
 * LexerSplitter.php
 *
 * Defines the characters, which are used to split the given SQL string.
 * Part of PHPSQLParser.
 *
 * PHP version 5
 *
 * LICENSE:
 * Copyright (c) 2010-2014 Justin Swanhart and André Rothe
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * @copyright 2010-2014 Justin Swanhart and André Rothe
 * @license   http://www.debian.org/misc/bsd.license  BSD License (3 Clause)
 *
 * @version   SVN: $Id$
 */

namespace PHPSQLParser\lexer;

/**
 * This class holds a sorted array of characters, which are used as stop token.
 * On every part of the array the given SQL string will be split into single tokens.
 * The array must be sorted by element size, longest first (3 chars -> 2 chars -> 1 char).
 *
 * @license http://www.debian.org/misc/bsd.license  BSD License (3 Clause)
 */
class LexerSplitter
{
    protected static $splitters = ['<=>', "\r\n", '!=', '>=', '<=', '<>', '<<', '>>', ':=', '\\', '&&', '||', ':=',
        '/*', '*/', '--', '>', '<', '|', '=', '^', '(', ')', "\t", "\n", "'", '"', '`',
        ',', '@', ' ', '+', '-', '*', '/', ';', ];

    /**
     * @var string Regex string pattern of splitters.
     */
    protected $splitterPattern;

    /**
     * Constructor.
     *
     * It initializes some fields.
     */
    public function __construct()
    {
        $this->splitterPattern = $this->convertSplittersToRegexPattern(self::$splitters);
    }

    /**
     * Get the regex pattern string of all the splitters
     *
     * @return string
     */
    public function getSplittersRegexPattern()
    {
        return $this->splitterPattern;
    }

    /**
     * Convert an array of splitter tokens to a regex pattern string.
     *
     * @param array $splitters
     *
     * @return string
     */
    public function convertSplittersToRegexPattern($splitters)
    {
        $regex_parts = [];

        foreach ($splitters as $part) {
            $part = preg_quote($part);

            switch ($part) {
                case "\r\n":
                    $part = '\r\n';
                    break;

                case "\t":
                    $part = '\t';
                    break;

                case "\n":
                    $part = '\n';
                    break;

                case ' ':
                    $part = '\s';
                    break;

                case '/':
                    $part = '\\/';
                    break;

                case '/\\*':
                    $part = '\\/\\*';
                    break;

                case '\\*/':
                    $part = '\\*\\/';
                    break;
            }

            $regex_parts[] = $part;
        }

        $pattern = implode('|', $regex_parts);

        return '/(' . $pattern . ')/';
    }
}
