Функция

<?php
/* implementation of my_strtok() in PHP */

/*
 * Description: string my_strtok(string $string, string $delimiter).
*
* Function my_strtok() splits a string ($string) into smaller
* strings (tokens), with each token being delimited by the delimiter
* string ($delimiter), considering string variables and comments
* in the $string argument. Note that the comparision is case-insensitive.
*
* Returns FALSE if there are no tokens left.
* Does not return empty tokens.
* Does not return the "delimiter" command as a token.
*
* Usage:
* The first call to my_strtok() uses the $string and $delimiter arguments.
* Every subsequent call to my_strtok() needs no arguments at all, or only
* the $delimiter argument to use, as it keeps track of where it is in the
* current string. To start over, or to tokenize a new string you simply
* call my_strtok() with the both arguments again to initialize it.
* The delimiter can be changed by the command "delimiter new_delimiter" in
* the $string argument (the command is case-insensitive).
*
* Example:
*  $res = my_strtok($query, $delimiter);
*  while ($res) {
*      echo "token = $res<br>";
*      $res = my_strtok();
*  }
*
* Author: Andrey Adaikin, IVA Team, <IVATeam@gmail.com>
* @version $Revision: 1.3 $, $Date: 2005/09/28 $
*/

function my_strtok($string = NULL, $delimiter = NULL) {

    static $str;            // lower case $string (equals to strtolower($string))
    static $str_original;   // stores $string argument
    static $len;            // length of the $string
    static $curr_pos;       // current position in the $string
    static $match_pos;      // position where the $delimiter is a substring of the $string
    static $delim;          // lower case $delimiter (equals to strtolower($delimiter))

    if (NULL === $delimiter) {
        if (NULL !== $string) {
            $delim = strtolower($string);
            $match_pos = -1;
        }
    } else {
        if (!is_string($string) || !is_string($delimiter)) {
            return FALSE;
        }
        $str_original = $string;
        $str = strtolower($str_original);
        $len = strlen($str);
        $curr_pos = 0;
        $match_pos = -1;
        $delim = strtolower($delimiter);
    }

    if ($curr_pos >= $len) {
        return FALSE;
    }

    if ("" == $delim) {
        $delim = ";";
        $match_pos = -1;
    }

    $dlen = strlen($delim);
    $result = FALSE;

    for ($i = $curr_pos; $i < $len; ++$i) {
        if ($match_pos < $i) {
            $match_pos = strpos($str, $delim, $i);
            if (FALSE === $match_pos) {
                $match_pos = $len;
            }
        }

        if ($i == $match_pos) {
            if ($i != $curr_pos) {
                $result = trim(substr($str_original, $curr_pos, $i - $curr_pos));
                if (strncasecmp($result, 'delimiter', 9) == 0 && (strlen($result) == 9 || FALSE !== strpos(" \t", $result{9}))) {
                    $delim = trim(strtolower(substr($result, 10)));
                    if ("" == $delim) { $delim = ";"; }
                    $match_pos = -1;
                    $result = FALSE;
                }
            }
            $i += $dlen;
            if ($match_pos < 0) {
                $dlen = strlen($delim);
            }
            $curr_pos = $i--;
            if ("" === $result) {
                $result = FALSE;
            }
            if (FALSE !== $result) {
                break;
            }
        } else if ($str{$i} == "'") {
            for ($j = $i+1; $j < $len; ++$j) {
                if ($str{$j} == "\\") ++$j;
                else if ($str{$j} == "'") break;
            }
            $i = $j;
        } else if ($str{$i} == "\"") {
            for ($j = $i+1; $j < $len; ++$j) {
                if ($str{$j} == "\\") ++$j;
                else if ($str{$j} == "\"") break;
            }
            $i = $j;
        } else if ($i < $len-1 && $str{$i} == "/" && $str{$i+1} == "*") {
            $j = $i+2;
            while ($j) {
                $j = strpos($str, "*/", $j);
                if (!$j || $str{$j-1} != "\\") { break; }
                ++$j;
            }
            if (!$j) { break; }
            $i = $j+1;
        } else if ($str{$i} == "#") {
            $j = strpos($str, "\n", $i+1) or strpos($str, "\r", $i+1);
            if (!$j) { break; }
            $i = $j;
        } else if ($i < $len-2 && $str{$i} == "-" && $str{$i+1} == "-" && FALSE !== strpos(" \t", $str{$i+2})) {
            $j = strpos($str, "\n", $i+3) or strpos($str, "\r", $i+1);
            if (!$j) { break; }
            $i = $j;
        } else if ($str{$i} == "\\") {
            ++$i;
        }
    }

    if (FALSE === $result && $curr_pos < $len) {
        $result = trim(substr($str_original, $curr_pos));
        if (strncasecmp($result, 'delimiter', 9) == 0 && (strlen($result) == 9 || FALSE !== strpos(" \t", $result{9}))) {
            $delim = trim(strtolower(substr($result, 10)));
            if ("" == $delim) { $delim = ";"; }
            $match_pos = -1;
            $dlen = strlen($delim);
            $result = FALSE;
        }
        $curr_pos = $len;
        if ("" === $result) {
            $result = FALSE;
        }
    }
    return $result;
}