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1'use strict';2 3/**4 * Checks if a status code is allowed in a close frame.5 *6 * @param {Number} code The status code7 * @return {Boolean} `true` if the status code is valid, else `false`8 * @public9 */10function isValidStatusCode(code) {11  return (12    (code >= 1000 &&13      code <= 1014 &&14      code !== 1004 &&15      code !== 1005 &&16      code !== 1006) ||17    (code >= 3000 && code <= 4999)18  );19}20 21/**22 * Checks if a given buffer contains only correct UTF-8.23 * Ported from https://www.cl.cam.ac.uk/%7Emgk25/ucs/utf8_check.c by24 * Markus Kuhn.25 *26 * @param {Buffer} buf The buffer to check27 * @return {Boolean} `true` if `buf` contains only correct UTF-8, else `false`28 * @public29 */30function _isValidUTF8(buf) {31  const len = buf.length;32  let i = 0;33 34  while (i < len) {35    if ((buf[i] & 0x80) === 0) {36      // 0xxxxxxx37      i++;38    } else if ((buf[i] & 0xe0) === 0xc0) {39      // 110xxxxx 10xxxxxx40      if (41        i + 1 === len ||42        (buf[i + 1] & 0xc0) !== 0x80 ||43        (buf[i] & 0xfe) === 0xc0 // Overlong44      ) {45        return false;46      }47 48      i += 2;49    } else if ((buf[i] & 0xf0) === 0xe0) {50      // 1110xxxx 10xxxxxx 10xxxxxx51      if (52        i + 2 >= len ||53        (buf[i + 1] & 0xc0) !== 0x80 ||54        (buf[i + 2] & 0xc0) !== 0x80 ||55        (buf[i] === 0xe0 && (buf[i + 1] & 0xe0) === 0x80) || // Overlong56        (buf[i] === 0xed && (buf[i + 1] & 0xe0) === 0xa0) // Surrogate (U+D800 - U+DFFF)57      ) {58        return false;59      }60 61      i += 3;62    } else if ((buf[i] & 0xf8) === 0xf0) {63      // 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx64      if (65        i + 3 >= len ||66        (buf[i + 1] & 0xc0) !== 0x80 ||67        (buf[i + 2] & 0xc0) !== 0x80 ||68        (buf[i + 3] & 0xc0) !== 0x80 ||69        (buf[i] === 0xf0 && (buf[i + 1] & 0xf0) === 0x80) || // Overlong70        (buf[i] === 0xf4 && buf[i + 1] > 0x8f) ||71        buf[i] > 0xf4 // > U+10FFFF72      ) {73        return false;74      }75 76      i += 4;77    } else {78      return false;79    }80  }81 82  return true;83}84 85try {86  let isValidUTF8 = require('utf-8-validate');87 88  /* istanbul ignore if */89  if (typeof isValidUTF8 === 'object') {90    isValidUTF8 = isValidUTF8.Validation.isValidUTF8; // utf-8-validate@<3.0.091  }92 93  module.exports = {94    isValidStatusCode,95    isValidUTF8(buf) {96      return buf.length < 150 ? _isValidUTF8(buf) : isValidUTF8(buf);97    }98  };99} catch (e) /* istanbul ignore next */ {100  module.exports = {101    isValidStatusCode,102    isValidUTF8: _isValidUTF8103  };104}105