‘use strict’;

/**

* Checks if a status code is allowed in a close frame.
*
* @param {Number} code The status code
* @return {Boolean} `true` if the status code is valid, else `false`
* @public
*/

function isValidStatusCode(code) {

return (
  (code >= 1000 &&
    code <= 1014 &&
    code !== 1004 &&
    code !== 1005 &&
    code !== 1006) ||
  (code >= 3000 && code <= 4999)
);

}

/**

* Checks if a given buffer contains only correct UTF-8.
* Ported from https://www.cl.cam.ac.uk/%7Emgk25/ucs/utf8_check.c by
* Markus Kuhn.
*
* @param {Buffer} buf The buffer to check
* @return {Boolean} `true` if `buf` contains only correct UTF-8, else `false`
* @public
*/

function _isValidUTF8(buf) {

const len = buf.length;
let i = 0;

while (i < len) {
  if ((buf[i] & 0x80) === 0) {
    // 0xxxxxxx
    i++;
  } else if ((buf[i] & 0xe0) === 0xc0) {
    // 110xxxxx 10xxxxxx
    if (
      i + 1 === len ||
      (buf[i + 1] & 0xc0) !== 0x80 ||
      (buf[i] & 0xfe) === 0xc0 // Overlong
    ) {
      return false;
    }

    i += 2;
  } else if ((buf[i] & 0xf0) === 0xe0) {
    // 1110xxxx 10xxxxxx 10xxxxxx
    if (
      i + 2 >= len ||
      (buf[i + 1] & 0xc0) !== 0x80 ||
      (buf[i + 2] & 0xc0) !== 0x80 ||
      (buf[i] === 0xe0 && (buf[i + 1] & 0xe0) === 0x80) || // Overlong
      (buf[i] === 0xed && (buf[i + 1] & 0xe0) === 0xa0) // Surrogate (U+D800 - U+DFFF)
    ) {
      return false;
    }

    i += 3;
  } else if ((buf[i] & 0xf8) === 0xf0) {
    // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx
    if (
      i + 3 >= len ||
      (buf[i + 1] & 0xc0) !== 0x80 ||
      (buf[i + 2] & 0xc0) !== 0x80 ||
      (buf[i + 3] & 0xc0) !== 0x80 ||
      (buf[i] === 0xf0 && (buf[i + 1] & 0xf0) === 0x80) || // Overlong
      (buf[i] === 0xf4 && buf[i + 1] > 0x8f) ||
      buf[i] > 0xf4 // > U+10FFFF
    ) {
      return false;
    }

    i += 4;
  } else {
    return false;
  }
}

return true;

}

try {

let isValidUTF8 = require('utf-8-validate');

/* istanbul ignore if */
if (typeof isValidUTF8 === 'object') {
  isValidUTF8 = isValidUTF8.Validation.isValidUTF8; // utf-8-validate@<3.0.0
}

module.exports = {
  isValidStatusCode,
  isValidUTF8(buf) {
    return buf.length < 150 ? _isValidUTF8(buf) : isValidUTF8(buf);
  }
};

} catch (e) /* istanbul ignore next */ {

module.exports = {
  isValidStatusCode,
  isValidUTF8: _isValidUTF8
};

}