<?php

/**
 * string substrpos(string $str, mixed $start [[, mixed $end], boolean $ignore_case])
 *
 * If $start is a string, substrpos will return the string from the position of the first occuring $start to $end
 *
 * If $end is a string, substrpos will return the string from $start to the position of the first occuring $end
 *
 * If the first character in (string) $start or (string) $end is '-', the last occuring string will be used.
 *
 * If $ignore_case is true, substrpos will not care about the case.
 * If $ignore_case is false (or anything that is not (boolean) true, the function will be case sensitive.
 *        Both of the above: only applies if either $start or $end are strings.
 *
 * echo substrpos('This is a string with 0123456789 numbers in it.', 5, '5');
 *        // Prints 'is a string with 01234';
 *
 * echo substrpos('This is a string with 0123456789 numbers in it.', '5', 5);
 *        // Prints '56789'
 *
 * echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-string')
 *        // Prints 's is a string with 0123456789 numbers in it and two '
 *
 * echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-STRING', true)
 *        // Prints 's is a string with 0123456789 numbers in it and two '
 *
 * echo substrpos('This is a string with 0123456789 numbers in it and two strings.', -60, '-STRING', false)
 *        // Prints 's is a string with 0123456789 numbers in it and two strings.'
 *
 * Warnings:
 *        Since $start and $end both take either a string or an integer:
 *            If the character or string you are searching $str for is a number, pass it as a quoted string.
 *        If $end is (integer) 0, an empty string will be returned.
 *        Since this function takes negative strings ('-search_string'):
 *            If the string your using in $start or $end is a '-' or begins with a '-' escape it with a '\'.
 *            This only applies to the *first* character of $start or $end.
 */

// Define stripos() if not defined (PHP < 5).
if (!is_callable("stripos")) {
    function stripos($str, $needle, $offset = 0) {
        return strpos(strtolower($str), strtolower($needle), $offset);
    }
}

function substrpos($str, $start, $end = false, $ignore_case = false) {
    // Use variable functions
    if ($ignore_case === true) {
        $strpos = 'stripos'; // stripos() is included above in case it's not defined (PHP < 5).
    } else {
        $strpos = 'strpos';
    }

    // If end is false, set it to the length of $str
    if ($end === false) {
        $end = strlen($str);
    }

    // If $start is a string do what's needed to make it an integer position for substr().
    if (is_string($start)) {
        // If $start begins with '-' start processing until there's no more matches and use the last one found.
        if ($start{0} == '-') {
            // Strip off the '-'
            $start = substr($start, 1);
            $found = false;
            $pos = 0;
            while(($curr_pos = $strpos($str, $start, $pos)) !== false) {
                $found = true;
                $pos = $curr_pos + 1;
            }
            if ($found === false) {
                $pos = false;
            } else {
                $pos -= 1;
            }
        } else {
            // If $start begins with '\-', strip off the '\'.
            if ($start{0} . $start{1} == '\-') {
                $start = substr($start, 1);
            }
            $pos = $strpos($str, $start);
        }
        $start = $pos !== false ? $pos : 0;
    }

    // Chop the string from $start to strlen($str).
    $str = substr($str, $start);

    // If $end is a string, do exactly what was done to $start, above.
    if (is_string($end)) {
        if ($end{0} == '-') {
            $end = substr($end, 1);
            $found = false;
            $pos = 0;
            while(($curr_pos = strpos($str, $end, $pos)) !== false) {
                $found = true;
                $pos = $curr_pos + 1;
            }
            if ($found === false) {
                $pos = false;
            } else {
                $pos -= 1;
            }
        } else {
            if ($end{0} . $end{1} == '\-') {
                $end = substr($end, 1);
            }
            $pos = $strpos($str, $end);
        }
        $end = $pos !== false ? $pos : strlen($str);
    }

    // Since $str has already been chopped at $start, we can pass 0 as the new $start for substr()
    return substr($str, 0, $end);
}

?>