Function crc32str

Picviewer CE+/Picviewer CE+.user.js:530–540

* Compute the crc32 of a string. * This is almost the same as the function crc32, but for strings. Using the * same function for the two use cases leads to horrible performances. * @param {Number} crc the starting value of the crc. * @param {String} str the string to use. * @param {Number} len

(crc, str, len, pos)

 * @return {Number} the computed crc32.
 */
function crc32str(crc, str, len, pos) {
    var t = crcTable, end = pos + len;

    crc = crc ^ (-1);

    for (var i = pos; i < end; i++ ) {
        crc = (crc >>> 8) ^ t[(crc ^ str.charCodeAt(i)) & 0xFF];
    }

    return (crc ^ (-1)); // >>> 0;
}

module.exports = function crc32wrapper(input, crc) {
    if (typeof input === "undefined" || !input.length) {