API/library/JsParser.php

<?php

namespace Shikiryu\LBCReposter;


class JsParser
{

    /**
     * @param $str
     * @param $data
     *
     * @return bool|string
     *
     * @throws JsParserException
     */
    public static function parse_jsobj($str, &$data)
    {
        $str = trim($str);
        if (strlen($str) < 1) return null;

        if ($str{0} != '{') {
            throw new JsParserException('The given string is not a JS object');
        }
        $str = substr($str, 1);

        /* While we have data, and it's not the end of this dict (the comma is needed for nested dicts) */
        while (strlen($str) && $str{0} != '}' && $str{0} != ',') {
            /* find the key */
            if ($str{0} == "'" || $str{0} == '"') {
                /* quoted key */
                list($str, $key) = self::parse_jsdata($str, ':');
            } else {
                $match = null;
                /* unquoted key */
                if (!preg_match('/^\s*[a-zA-z_][a-zA-Z_\d]*\s*:/', $str, $match)) {
                    throw new JsParserException('Invalid key ("' . $str . '")');
                }
                $key = $match[0];
                $str = substr($str, strlen($key));
                $key = trim(substr($key, 0, -1)); /* discard the ':' */
            }

            list($str, $data[$key]) = self::parse_jsdata($str, '}');
        }

        return substr($str, 1);
    }

    /**
     * @param $str
     * @param $term
     * @return bool|int|mixed
     * @throws JsParserException
     */
    public static function comma_or_term_pos($str, $term)
    {
        $cpos = strpos($str, ',');
        $tpos = strpos($str, $term);
        if ($cpos === false && $tpos === false) {
            throw new JsParserException('unterminated dict or array');
        } else if ($cpos === false) {
            return $tpos;
        } else if ($tpos === false) {
            return $cpos;
        }
        return min($tpos, $cpos);
    }

    /**
     * @param $str
     * @param string $term
     * @return array
     * @throws JsParserException
     */
    public static function parse_jsdata($str, $term = "}")
    {
        $str = trim($str);


        if (is_numeric($str{0} . "0")) {
            /* a number (int or float) */
            $newpos = self::comma_or_term_pos($str, $term);
            $num = trim(substr($str, 0, $newpos));
            $str = substr($str, $newpos + 1); /* discard num and comma */
            if (!is_numeric($num)) {
                throw new JsParserException('OOPSIE while parsing number: "' . $num . '"');
            }
            return array(trim($str), $num + 0);
        } else if ($str{0} == '"' || $str{0} == "'") {
            /* string */
            $q = $str{0};
            $offset = 1;
            do {
                $pos = strpos($str, $q, $offset);
                $offset = $pos;
            } while ($str{$pos - 1} == '\\'); /* find un-escaped quote */
            $data = substr($str, 1, $pos - 1);
            $str = substr($str, $pos);
            $pos = self::comma_or_term_pos($str, $term);
            $str = substr($str, $pos + 1);
            return array(trim($str), $data);
        } else if ($str{0} == '{') {
            /* dict */
            $data = array();
            $str = self::parse_jsobj($str, $data);
            return array($str, $data);
        } else if ($str{0} == '[') {
            /* array */
            $arr = array();
            $str = substr($str, 1);
            if (']' === $str[0]) {
                return ['', $arr];
            }
            while (strlen($str) && $str{0} != $term && $str{0} != ',') {
                $val = null;
                list($str, $val) = self::parse_jsdata($str, ']');
                $arr[] = $val;
                $str = trim($str);
            }
            $str = trim(substr($str, 1));
            return array($str, $arr);
        } else if (stripos($str, 'true') === 0) {
            /* true */
            $pos = self::comma_or_term_pos($str, $term);
            $str = substr($str, $pos + 1); /* discard terminator */
            return array(trim($str), true);
        } else if (stripos($str, 'false') === 0) {
            /* false */
            $pos = self::comma_or_term_pos($str, $term);
            $str = substr($str, $pos + 1); /* discard terminator */
            return array(trim($str), false);
        } else if (stripos($str, 'null') === 0) {
            /* null */
            $pos = self::comma_or_term_pos($str, $term);
            $str = substr($str, $pos + 1); /* discard terminator */
            return array(trim($str), null);
        } else if (strpos($str, 'undefined') === 0) {
            /* null */
            $pos = self::comma_or_term_pos($str, $term);
            $str = substr($str, $pos + 1); /* discard terminator */
            return array(trim($str), null);
        } else {
            throw new JsParserException('Cannot figure out how to parse "' . $str . '" (term is ' . $term . ')');
        }
    }
}