smartmeter-app/utils/blufi/crypto/lib/buffer.js

/*!
 * The buffer module from node.js, for the browser.
 *
 * @author   Feross Aboukhadijeh <https://feross.org>
 * @license  MIT
 */

/* eslint-disable no-proto */
'use strict';

var base64 = require("./base64-js.js");

var ieee754 = require("./ieee754.js");

exports.Buffer = Buffer;
exports.SlowBuffer = SlowBuffer;
exports.INSPECT_MAX_BYTES = 50;
var K_MAX_LENGTH = 0x7fffffff;
exports.kMaxLength = K_MAX_LENGTH;
/**
 * If `Buffer.TYPED_ARRAY_SUPPORT`:
 *   === true    Use Uint8Array implementation (fastest)
 *   === false   Print warning and recommend using `buffer` v4.x which has an Object
 *               implementation (most compatible, even IE6)
 *
 * Browsers that support typed arrays are IE 10+, Firefox 4+, Chrome 7+, Safari 5.1+,
 * Opera 11.6+, iOS 4.2+.
 *
 * We report that the browser does not support typed arrays if the are not subclassable
 * using __proto__. Firefox 4-29 lacks support for adding new properties to `Uint8Array`
 * (See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438). IE 10 lacks support
 * for __proto__ and has a buggy typed array implementation.
 */

Buffer.TYPED_ARRAY_SUPPORT = typedArraySupport();

if (!Buffer.TYPED_ARRAY_SUPPORT && typeof console !== 'undefined' && typeof console.error === 'function') {
  console.error('This browser lacks typed array (Uint8Array) support which is required by ' + '`buffer` v5.x. Use `buffer` v4.x if you require old browser support.');
}

function typedArraySupport() {
  // Can typed array instances can be augmented?
  try {
    var arr = new Uint8Array(1);
    arr.__proto__ = {
      __proto__: Uint8Array.prototype,
      foo: function () {
        return 42;
      }
    };
    return arr.foo() === 42;
  } catch (e) {
    return false;
  }
}

Object.defineProperty(Buffer.prototype, 'parent', {
  enumerable: true,
  get: function () {
    if (!Buffer.isBuffer(this)) return undefined;
    return this.buffer;
  }
});
Object.defineProperty(Buffer.prototype, 'offset', {
  enumerable: true,
  get: function () {
    if (!Buffer.isBuffer(this)) return undefined;
    return this.byteOffset;
  }
});

function createBuffer(length) {
  if (length > K_MAX_LENGTH) {
    throw new RangeError('The value "' + length + '" is invalid for option "size"');
  } // Return an augmented `Uint8Array` instance


  var buf = new Uint8Array(length);
  buf.__proto__ = Buffer.prototype;
  return buf;
}
/**
 * The Buffer constructor returns instances of `Uint8Array` that have their
 * prototype changed to `Buffer.prototype`. Furthermore, `Buffer` is a subclass of
 * `Uint8Array`, so the returned instances will have all the node `Buffer` methods
 * and the `Uint8Array` methods. Square bracket notation works as expected -- it
 * returns a single octet.
 *
 * The `Uint8Array` prototype remains unmodified.
 */


function Buffer(arg, encodingOrOffset, length) {
  // Common case.
  if (typeof arg === 'number') {
    if (typeof encodingOrOffset === 'string') {
      throw new TypeError('The "string" argument must be of type string. Received type number');
    }

    return allocUnsafe(arg);
  }

  return from(arg, encodingOrOffset, length);
} // Fix subarray() in ES2016. See: https://github.com/feross/buffer/pull/97


if (typeof Symbol !== 'undefined' && Symbol.species != null && Buffer[Symbol.species] === Buffer) {
  Object.defineProperty(Buffer, Symbol.species, {
    value: null,
    configurable: true,
    enumerable: false,
    writable: false
  });
}

Buffer.poolSize = 8192; // not used by this implementation

function from(value, encodingOrOffset, length) {
  if (typeof value === 'string') {
    return fromString(value, encodingOrOffset);
  }

  if (ArrayBuffer.isView(value)) {
    return fromArrayLike(value);
  }

  if (value == null) {
    throw TypeError('The first argument must be one of type string, Buffer, ArrayBuffer, Array, ' + 'or Array-like Object. Received type ' + typeof value);
  }

  if (isInstance(value, ArrayBuffer) || value && isInstance(value.buffer, ArrayBuffer)) {
    return fromArrayBuffer(value, encodingOrOffset, length);
  }

  if (typeof value === 'number') {
    throw new TypeError('The "value" argument must not be of type number. Received type number');
  }

  var valueOf = value.valueOf && value.valueOf();

  if (valueOf != null && valueOf !== value) {
    return Buffer.from(valueOf, encodingOrOffset, length);
  }

  var b = fromObject(value);
  if (b) return b;

  if (typeof Symbol !== 'undefined' && Symbol.toPrimitive != null && typeof value[Symbol.toPrimitive] === 'function') {
    return Buffer.from(value[Symbol.toPrimitive]('string'), encodingOrOffset, length);
  }

  throw new TypeError('The first argument must be one of type string, Buffer, ArrayBuffer, Array, ' + 'or Array-like Object. Received type ' + typeof value);
}
/**
 * Functionally equivalent to Buffer(arg, encoding) but throws a TypeError
 * if value is a number.
 * Buffer.from(str[, encoding])
 * Buffer.from(array)
 * Buffer.from(buffer)
 * Buffer.from(arrayBuffer[, byteOffset[, length]])
 **/


Buffer.from = function (value, encodingOrOffset, length) {
  return from(value, encodingOrOffset, length);
}; // Note: Change prototype *after* Buffer.from is defined to workaround Chrome bug:
// https://github.com/feross/buffer/pull/148


Buffer.prototype.__proto__ = Uint8Array.prototype;
Buffer.__proto__ = Uint8Array;

function assertSize(size) {
  if (typeof size !== 'number') {
    throw new TypeError('"size" argument must be of type number');
  } else if (size < 0) {
    throw new RangeError('The value "' + size + '" is invalid for option "size"');
  }
}

function alloc(size, fill, encoding) {
  assertSize(size);

  if (size <= 0) {
    return createBuffer(size);
  }

  if (fill !== undefined) {
    // Only pay attention to encoding if it's a string. This
    // prevents accidentally sending in a number that would
    // be interpretted as a start offset.
    return typeof encoding === 'string' ? createBuffer(size).fill(fill, encoding) : createBuffer(size).fill(fill);
  }

  return createBuffer(size);
}
/**
 * Creates a new filled Buffer instance.
 * alloc(size[, fill[, encoding]])
 **/


Buffer.alloc = function (size, fill, encoding) {
  return alloc(size, fill, encoding);
};

function allocUnsafe(size) {
  assertSize(size);
  return createBuffer(size < 0 ? 0 : checked(size) | 0);
}
/**
 * Equivalent to Buffer(num), by default creates a non-zero-filled Buffer instance.
 * */


Buffer.allocUnsafe = function (size) {
  return allocUnsafe(size);
};
/**
 * Equivalent to SlowBuffer(num), by default creates a non-zero-filled Buffer instance.
 */


Buffer.allocUnsafeSlow = function (size) {
  return allocUnsafe(size);
};

function fromString(string, encoding) {
  if (typeof encoding !== 'string' || encoding === '') {
    encoding = 'utf8';
  }

  if (!Buffer.isEncoding(encoding)) {
    throw new TypeError('Unknown encoding: ' + encoding);
  }

  var length = byteLength(string, encoding) | 0;
  var buf = createBuffer(length);
  var actual = buf.write(string, encoding);

  if (actual !== length) {
    // Writing a hex string, for example, that contains invalid characters will
    // cause everything after the first invalid character to be ignored. (e.g.
    // 'abxxcd' will be treated as 'ab')
    buf = buf.slice(0, actual);
  }

  return buf;
}

function fromArrayLike(array) {
  var length = array.length < 0 ? 0 : checked(array.length) | 0;
  var buf = createBuffer(length);

  for (var i = 0; i < length; i += 1) {
    buf[i] = array[i] & 255;
  }

  return buf;
}

function fromArrayBuffer(array, byteOffset, length) {
  if (byteOffset < 0 || array.byteLength < byteOffset) {
    throw new RangeError('"offset" is outside of buffer bounds');
  }

  if (array.byteLength < byteOffset + (length || 0)) {
    throw new RangeError('"length" is outside of buffer bounds');
  }

  var buf;

  if (byteOffset === undefined && length === undefined) {
    buf = new Uint8Array(array);
  } else if (length === undefined) {
    buf = new Uint8Array(array, byteOffset);
  } else {
    buf = new Uint8Array(array, byteOffset, length);
  } // Return an augmented `Uint8Array` instance


  buf.__proto__ = Buffer.prototype;
  return buf;
}

function fromObject(obj) {
  if (Buffer.isBuffer(obj)) {
    var len = checked(obj.length) | 0;
    var buf = createBuffer(len);

    if (buf.length === 0) {
      return buf;
    }

    obj.copy(buf, 0, 0, len);
    return buf;
  }

  if (obj.length !== undefined) {
    if (typeof obj.length !== 'number' || numberIsNaN(obj.length)) {
      return createBuffer(0);
    }

    return fromArrayLike(obj);
  }

  if (obj.type === 'Buffer' && Array.isArray(obj.data)) {
    return fromArrayLike(obj.data);
  }
}

function checked(length) {
  // Note: cannot use `length < K_MAX_LENGTH` here because that fails when
  // length is NaN (which is otherwise coerced to zero.)
  if (length >= K_MAX_LENGTH) {
    throw new RangeError('Attempt to allocate Buffer larger than maximum ' + 'size: 0x' + K_MAX_LENGTH.toString(16) + ' bytes');
  }

  return length | 0;
}

function SlowBuffer(length) {
  if (+length != length) {
    // eslint-disable-line eqeqeq
    length = 0;
  }

  return Buffer.alloc(+length);
}

Buffer.isBuffer = function isBuffer(b) {
  return b != null && b._isBuffer === true && b !== Buffer.prototype; // so Buffer.isBuffer(Buffer.prototype) will be false
};

Buffer.compare = function compare(a, b) {
  if (isInstance(a, Uint8Array)) a = Buffer.from(a, a.offset, a.byteLength);
  if (isInstance(b, Uint8Array)) b = Buffer.from(b, b.offset, b.byteLength);

  if (!Buffer.isBuffer(a) || !Buffer.isBuffer(b)) {
    throw new TypeError('The "buf1", "buf2" arguments must be one of type Buffer or Uint8Array');
  }

  if (a === b) return 0;
  var x = a.length;
  var y = b.length;

  for (var i = 0, len = Math.min(x, y); i < len; ++i) {
    if (a[i] !== b[i]) {
      x = a[i];
      y = b[i];
      break;
    }
  }

  if (x < y) return -1;
  if (y < x) return 1;
  return 0;
};

Buffer.isEncoding = function isEncoding(encoding) {
  switch (String(encoding).toLowerCase()) {
    case 'hex':
    case 'utf8':
    case 'utf-8':
    case 'ascii':
    case 'latin1':
    case 'binary':
    case 'base64':
    case 'ucs2':
    case 'ucs-2':
    case 'utf16le':
    case 'utf-16le':
      return true;

    default:
      return false;
  }
};

Buffer.concat = function concat(list, length) {
  if (!Array.isArray(list)) {
    throw new TypeError('"list" argument must be an Array of Buffers');
  }

  if (list.length === 0) {
    return Buffer.alloc(0);
  }

  var i;

  if (length === undefined) {
    length = 0;

    for (i = 0; i < list.length; ++i) {
      length += list[i].length;
    }
  }

  var buffer = Buffer.allocUnsafe(length);
  var pos = 0;

  for (i = 0; i < list.length; ++i) {
    var buf = list[i];

    if (isInstance(buf, Uint8Array)) {
      buf = Buffer.from(buf);
    }

    if (!Buffer.isBuffer(buf)) {
      throw new TypeError('"list" argument must be an Array of Buffers');
    }

    buf.copy(buffer, pos);
    pos += buf.length;
  }

  return buffer;
};

function byteLength(string, encoding) {
  if (Buffer.isBuffer(string)) {
    return string.length;
  }

  if (ArrayBuffer.isView(string) || isInstance(string, ArrayBuffer)) {
    return string.byteLength;
  }

  if (typeof string !== 'string') {
    throw new TypeError('The "string" argument must be one of type string, Buffer, or ArrayBuffer. ' + 'Received type ' + typeof string);
  }

  var len = string.length;
  var mustMatch = arguments.length > 2 && arguments[2] === true;
  if (!mustMatch && len === 0) return 0; // Use a for loop to avoid recursion

  var loweredCase = false;

  for (;;) {
    switch (encoding) {
      case 'ascii':
      case 'latin1':
      case 'binary':
        return len;

      case 'utf8':
      case 'utf-8':
        return utf8ToBytes(string).length;

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return len * 2;

      case 'hex':
        return len >>> 1;

      case 'base64':
        return base64ToBytes(string).length;

      default:
        if (loweredCase) {
          return mustMatch ? -1 : utf8ToBytes(string).length; // assume utf8
        }

        encoding = ('' + encoding).toLowerCase();
        loweredCase = true;
    }
  }
}

Buffer.byteLength = byteLength;

function slowToString(encoding, start, end) {
  var loweredCase = false; // No need to verify that "this.length <= MAX_UINT32" since it's a read-only
  // property of a typed array.
  // This behaves neither like String nor Uint8Array in that we set start/end
  // to their upper/lower bounds if the value passed is out of range.
  // undefined is handled specially as per ECMA-262 6th Edition,
  // Section 13.3.3.7 Runtime Semantics: KeyedBindingInitialization.

  if (start === undefined || start < 0) {
    start = 0;
  } // Return early if start > this.length. Done here to prevent potential uint32
  // coercion fail below.


  if (start > this.length) {
    return '';
  }

  if (end === undefined || end > this.length) {
    end = this.length;
  }

  if (end <= 0) {
    return '';
  } // Force coersion to uint32. This will also coerce falsey/NaN values to 0.


  end >>>= 0;
  start >>>= 0;

  if (end <= start) {
    return '';
  }

  if (!encoding) encoding = 'utf8';

  while (true) {
    switch (encoding) {
      case 'hex':
        return hexSlice(this, start, end);

      case 'utf8':
      case 'utf-8':
        return utf8Slice(this, start, end);

      case 'ascii':
        return asciiSlice(this, start, end);

      case 'latin1':
      case 'binary':
        return latin1Slice(this, start, end);

      case 'base64':
        return base64Slice(this, start, end);

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return utf16leSlice(this, start, end);

      default:
        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding);
        encoding = (encoding + '').toLowerCase();
        loweredCase = true;
    }
  }
} // This property is used by `Buffer.isBuffer` (and the `is-buffer` npm package)
// to detect a Buffer instance. It's not possible to use `instanceof Buffer`
// reliably in a browserify context because there could be multiple different
// copies of the 'buffer' package in use. This method works even for Buffer
// instances that were created from another copy of the `buffer` package.
// See: https://github.com/feross/buffer/issues/154


Buffer.prototype._isBuffer = true;

function swap(b, n, m) {
  var i = b[n];
  b[n] = b[m];
  b[m] = i;
}

Buffer.prototype.swap16 = function swap16() {
  var len = this.length;

  if (len % 2 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 16-bits');
  }

  for (var i = 0; i < len; i += 2) {
    swap(this, i, i + 1);
  }

  return this;
};

Buffer.prototype.swap32 = function swap32() {
  var len = this.length;

  if (len % 4 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 32-bits');
  }

  for (var i = 0; i < len; i += 4) {
    swap(this, i, i + 3);
    swap(this, i + 1, i + 2);
  }

  return this;
};

Buffer.prototype.swap64 = function swap64() {
  var len = this.length;

  if (len % 8 !== 0) {
    throw new RangeError('Buffer size must be a multiple of 64-bits');
  }

  for (var i = 0; i < len; i += 8) {
    swap(this, i, i + 7);
    swap(this, i + 1, i + 6);
    swap(this, i + 2, i + 5);
    swap(this, i + 3, i + 4);
  }

  return this;
};

Buffer.prototype.toString = function toString() {
  var length = this.length;
  if (length === 0) return '';
  if (arguments.length === 0) return utf8Slice(this, 0, length);
  return slowToString.apply(this, arguments);
};

Buffer.prototype.toLocaleString = Buffer.prototype.toString;

Buffer.prototype.equals = function equals(b) {
  if (!Buffer.isBuffer(b)) throw new TypeError('Argument must be a Buffer');
  if (this === b) return true;
  return Buffer.compare(this, b) === 0;
};

Buffer.prototype.inspect = function inspect() {
  var str = '';
  var max = exports.INSPECT_MAX_BYTES;
  str = this.toString('hex', 0, max).replace(/(.{2})/g, '$1 ').trim();
  if (this.length > max) str += ' ... ';
  return '<Buffer ' + str + '>';
};

Buffer.prototype.compare = function compare(target, start, end, thisStart, thisEnd) {
  if (isInstance(target, Uint8Array)) {
    target = Buffer.from(target, target.offset, target.byteLength);
  }

  if (!Buffer.isBuffer(target)) {
    throw new TypeError('The "target" argument must be one of type Buffer or Uint8Array. ' + 'Received type ' + typeof target);
  }

  if (start === undefined) {
    start = 0;
  }

  if (end === undefined) {
    end = target ? target.length : 0;
  }

  if (thisStart === undefined) {
    thisStart = 0;
  }

  if (thisEnd === undefined) {
    thisEnd = this.length;
  }

  if (start < 0 || end > target.length || thisStart < 0 || thisEnd > this.length) {
    throw new RangeError('out of range index');
  }

  if (thisStart >= thisEnd && start >= end) {
    return 0;
  }

  if (thisStart >= thisEnd) {
    return -1;
  }

  if (start >= end) {
    return 1;
  }

  start >>>= 0;
  end >>>= 0;
  thisStart >>>= 0;
  thisEnd >>>= 0;
  if (this === target) return 0;
  var x = thisEnd - thisStart;
  var y = end - start;
  var len = Math.min(x, y);
  var thisCopy = this.slice(thisStart, thisEnd);
  var targetCopy = target.slice(start, end);

  for (var i = 0; i < len; ++i) {
    if (thisCopy[i] !== targetCopy[i]) {
      x = thisCopy[i];
      y = targetCopy[i];
      break;
    }
  }

  if (x < y) return -1;
  if (y < x) return 1;
  return 0;
}; // Finds either the first index of `val` in `buffer` at offset >= `byteOffset`,
// OR the last index of `val` in `buffer` at offset <= `byteOffset`.
//
// Arguments:
// - buffer - a Buffer to search
// - val - a string, Buffer, or number
// - byteOffset - an index into `buffer`; will be clamped to an int32
// - encoding - an optional encoding, relevant is val is a string
// - dir - true for indexOf, false for lastIndexOf


function bidirectionalIndexOf(buffer, val, byteOffset, encoding, dir) {
  // Empty buffer means no match
  if (buffer.length === 0) return -1; // Normalize byteOffset

  if (typeof byteOffset === 'string') {
    encoding = byteOffset;
    byteOffset = 0;
  } else if (byteOffset > 0x7fffffff) {
    byteOffset = 0x7fffffff;
  } else if (byteOffset < -0x80000000) {
    byteOffset = -0x80000000;
  }

  byteOffset = +byteOffset; // Coerce to Number.

  if (numberIsNaN(byteOffset)) {
    // byteOffset: it it's undefined, null, NaN, "foo", etc, search whole buffer
    byteOffset = dir ? 0 : buffer.length - 1;
  } // Normalize byteOffset: negative offsets start from the end of the buffer


  if (byteOffset < 0) byteOffset = buffer.length + byteOffset;

  if (byteOffset >= buffer.length) {
    if (dir) return -1;else byteOffset = buffer.length - 1;
  } else if (byteOffset < 0) {
    if (dir) byteOffset = 0;else return -1;
  } // Normalize val


  if (typeof val === 'string') {
    val = Buffer.from(val, encoding);
  } // Finally, search either indexOf (if dir is true) or lastIndexOf


  if (Buffer.isBuffer(val)) {
    // Special case: looking for empty string/buffer always fails
    if (val.length === 0) {
      return -1;
    }

    return arrayIndexOf(buffer, val, byteOffset, encoding, dir);
  } else if (typeof val === 'number') {
    val = val & 0xFF; // Search for a byte value [0-255]

    if (typeof Uint8Array.prototype.indexOf === 'function') {
      if (dir) {
        return Uint8Array.prototype.indexOf.call(buffer, val, byteOffset);
      } else {
        return Uint8Array.prototype.lastIndexOf.call(buffer, val, byteOffset);
      }
    }

    return arrayIndexOf(buffer, [val], byteOffset, encoding, dir);
  }

  throw new TypeError('val must be string, number or Buffer');
}

function arrayIndexOf(arr, val, byteOffset, encoding, dir) {
  var indexSize = 1;
  var arrLength = arr.length;
  var valLength = val.length;

  if (encoding !== undefined) {
    encoding = String(encoding).toLowerCase();

    if (encoding === 'ucs2' || encoding === 'ucs-2' || encoding === 'utf16le' || encoding === 'utf-16le') {
      if (arr.length < 2 || val.length < 2) {
        return -1;
      }

      indexSize = 2;
      arrLength /= 2;
      valLength /= 2;
      byteOffset /= 2;
    }
  }

  function read(buf, i) {
    if (indexSize === 1) {
      return buf[i];
    } else {
      return buf.readUInt16BE(i * indexSize);
    }
  }

  var i;

  if (dir) {
    var foundIndex = -1;

    for (i = byteOffset; i < arrLength; i++) {
      if (read(arr, i) === read(val, foundIndex === -1 ? 0 : i - foundIndex)) {
        if (foundIndex === -1) foundIndex = i;
        if (i - foundIndex + 1 === valLength) return foundIndex * indexSize;
      } else {
        if (foundIndex !== -1) i -= i - foundIndex;
        foundIndex = -1;
      }
    }
  } else {
    if (byteOffset + valLength > arrLength) byteOffset = arrLength - valLength;

    for (i = byteOffset; i >= 0; i--) {
      var found = true;

      for (var j = 0; j < valLength; j++) {
        if (read(arr, i + j) !== read(val, j)) {
          found = false;
          break;
        }
      }

      if (found) return i;
    }
  }

  return -1;
}

Buffer.prototype.includes = function includes(val, byteOffset, encoding) {
  return this.indexOf(val, byteOffset, encoding) !== -1;
};

Buffer.prototype.indexOf = function indexOf(val, byteOffset, encoding) {
  return bidirectionalIndexOf(this, val, byteOffset, encoding, true);
};

Buffer.prototype.lastIndexOf = function lastIndexOf(val, byteOffset, encoding) {
  return bidirectionalIndexOf(this, val, byteOffset, encoding, false);
};

function hexWrite(buf, string, offset, length) {
  offset = Number(offset) || 0;
  var remaining = buf.length - offset;

  if (!length) {
    length = remaining;
  } else {
    length = Number(length);

    if (length > remaining) {
      length = remaining;
    }
  }

  var strLen = string.length;

  if (length > strLen / 2) {
    length = strLen / 2;
  }

  for (var i = 0; i < length; ++i) {
    var parsed = parseInt(string.substr(i * 2, 2), 16);
    if (numberIsNaN(parsed)) return i;
    buf[offset + i] = parsed;
  }

  return i;
}

function utf8Write(buf, string, offset, length) {
  return blitBuffer(utf8ToBytes(string, buf.length - offset), buf, offset, length);
}

function asciiWrite(buf, string, offset, length) {
  return blitBuffer(asciiToBytes(string), buf, offset, length);
}

function latin1Write(buf, string, offset, length) {
  return asciiWrite(buf, string, offset, length);
}

function base64Write(buf, string, offset, length) {
  return blitBuffer(base64ToBytes(string), buf, offset, length);
}

function ucs2Write(buf, string, offset, length) {
  return blitBuffer(utf16leToBytes(string, buf.length - offset), buf, offset, length);
}

Buffer.prototype.write = function write(string, offset, length, encoding) {
  // Buffer#write(string)
  if (offset === undefined) {
    encoding = 'utf8';
    length = this.length;
    offset = 0; // Buffer#write(string, encoding)
  } else if (length === undefined && typeof offset === 'string') {
    encoding = offset;
    length = this.length;
    offset = 0; // Buffer#write(string, offset[, length][, encoding])
  } else if (isFinite(offset)) {
    offset = offset >>> 0;

    if (isFinite(length)) {
      length = length >>> 0;
      if (encoding === undefined) encoding = 'utf8';
    } else {
      encoding = length;
      length = undefined;
    }
  } else {
    throw new Error('Buffer.write(string, encoding, offset[, length]) is no longer supported');
  }

  var remaining = this.length - offset;
  if (length === undefined || length > remaining) length = remaining;

  if (string.length > 0 && (length < 0 || offset < 0) || offset > this.length) {
    throw new RangeError('Attempt to write outside buffer bounds');
  }

  if (!encoding) encoding = 'utf8';
  var loweredCase = false;

  for (;;) {
    switch (encoding) {
      case 'hex':
        return hexWrite(this, string, offset, length);

      case 'utf8':
      case 'utf-8':
        return utf8Write(this, string, offset, length);

      case 'ascii':
        return asciiWrite(this, string, offset, length);

      case 'latin1':
      case 'binary':
        return latin1Write(this, string, offset, length);

      case 'base64':
        // Warning: maxLength not taken into account in base64Write
        return base64Write(this, string, offset, length);

      case 'ucs2':
      case 'ucs-2':
      case 'utf16le':
      case 'utf-16le':
        return ucs2Write(this, string, offset, length);

      default:
        if (loweredCase) throw new TypeError('Unknown encoding: ' + encoding);
        encoding = ('' + encoding).toLowerCase();
        loweredCase = true;
    }
  }
};

Buffer.prototype.toJSON = function toJSON() {
  return {
    type: 'Buffer',
    data: Array.prototype.slice.call(this._arr || this, 0)
  };
};

function base64Slice(buf, start, end) {
  if (start === 0 && end === buf.length) {
    return base64.fromByteArray(buf);
  } else {
    return base64.fromByteArray(buf.slice(start, end));
  }
}

function utf8Slice(buf, start, end) {
  end = Math.min(buf.length, end);
  var res = [];
  var i = start;

  while (i < end) {
    var firstByte = buf[i];
    var codePoint = null;
    var bytesPerSequence = firstByte > 0xEF ? 4 : firstByte > 0xDF ? 3 : firstByte > 0xBF ? 2 : 1;

    if (i + bytesPerSequence <= end) {
      var secondByte, thirdByte, fourthByte, tempCodePoint;

      switch (bytesPerSequence) {
        case 1:
          if (firstByte < 0x80) {
            codePoint = firstByte;
          }

          break;

        case 2:
          secondByte = buf[i + 1];

          if ((secondByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0x1F) << 0x6 | secondByte & 0x3F;

            if (tempCodePoint > 0x7F) {
              codePoint = tempCodePoint;
            }
          }

          break;

        case 3:
          secondByte = buf[i + 1];
          thirdByte = buf[i + 2];

          if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0xF) << 0xC | (secondByte & 0x3F) << 0x6 | thirdByte & 0x3F;

            if (tempCodePoint > 0x7FF && (tempCodePoint < 0xD800 || tempCodePoint > 0xDFFF)) {
              codePoint = tempCodePoint;
            }
          }

          break;

        case 4:
          secondByte = buf[i + 1];
          thirdByte = buf[i + 2];
          fourthByte = buf[i + 3];

          if ((secondByte & 0xC0) === 0x80 && (thirdByte & 0xC0) === 0x80 && (fourthByte & 0xC0) === 0x80) {
            tempCodePoint = (firstByte & 0xF) << 0x12 | (secondByte & 0x3F) << 0xC | (thirdByte & 0x3F) << 0x6 | fourthByte & 0x3F;

            if (tempCodePoint > 0xFFFF && tempCodePoint < 0x110000) {
              codePoint = tempCodePoint;
            }
          }

      }
    }

    if (codePoint === null) {
      // we did not generate a valid codePoint so insert a
      // replacement char (U+FFFD) and advance only 1 byte
      codePoint = 0xFFFD;
      bytesPerSequence = 1;
    } else if (codePoint > 0xFFFF) {
      // encode to utf16 (surrogate pair dance)
      codePoint -= 0x10000;
      res.push(codePoint >>> 10 & 0x3FF | 0xD800);
      codePoint = 0xDC00 | codePoint & 0x3FF;
    }

    res.push(codePoint);
    i += bytesPerSequence;
  }

  return decodeCodePointsArray(res);
} // Based on http://stackoverflow.com/a/22747272/680742, the browser with
// the lowest limit is Chrome, with 0x10000 args.
// We go 1 magnitude less, for safety


var MAX_ARGUMENTS_LENGTH = 0x1000;

function decodeCodePointsArray(codePoints) {
  var len = codePoints.length;

  if (len <= MAX_ARGUMENTS_LENGTH) {
    return String.fromCharCode.apply(String, codePoints); // avoid extra slice()
  } // Decode in chunks to avoid "call stack size exceeded".


  var res = '';
  var i = 0;

  while (i < len) {
    res += String.fromCharCode.apply(String, codePoints.slice(i, i += MAX_ARGUMENTS_LENGTH));
  }

  return res;
}

function asciiSlice(buf, start, end) {
  var ret = '';
  end = Math.min(buf.length, end);

  for (var i = start; i < end; ++i) {
    ret += String.fromCharCode(buf[i] & 0x7F);
  }

  return ret;
}

function latin1Slice(buf, start, end) {
  var ret = '';
  end = Math.min(buf.length, end);

  for (var i = start; i < end; ++i) {
    ret += String.fromCharCode(buf[i]);
  }

  return ret;
}

function hexSlice(buf, start, end) {
  var len = buf.length;
  if (!start || start < 0) start = 0;
  if (!end || end < 0 || end > len) end = len;
  var out = '';

  for (var i = start; i < end; ++i) {
    out += toHex(buf[i]);
  }

  return out;
}

function utf16leSlice(buf, start, end) {
  var bytes = buf.slice(start, end);
  var res = '';

  for (var i = 0; i < bytes.length; i += 2) {
    res += String.fromCharCode(bytes[i] + bytes[i + 1] * 256);
  }

  return res;
}

Buffer.prototype.slice = function slice(start, end) {
  var len = this.length;
  start = ~~start;
  end = end === undefined ? len : ~~end;

  if (start < 0) {
    start += len;
    if (start < 0) start = 0;
  } else if (start > len) {
    start = len;
  }

  if (end < 0) {
    end += len;
    if (end < 0) end = 0;
  } else if (end > len) {
    end = len;
  }

  if (end < start) end = start;
  var newBuf = this.subarray(start, end); // Return an augmented `Uint8Array` instance

  newBuf.__proto__ = Buffer.prototype;
  return newBuf;
};
/*
 * Need to make sure that buffer isn't trying to write out of bounds.
 */


function checkOffset(offset, ext, length) {
  if (offset % 1 !== 0 || offset < 0) throw new RangeError('offset is not uint');
  if (offset + ext > length) throw new RangeError('Trying to access beyond buffer length');
}

Buffer.prototype.readUIntLE = function readUIntLE(offset, byteLength, noAssert) {
  offset = offset >>> 0;
  byteLength = byteLength >>> 0;
  if (!noAssert) checkOffset(offset, byteLength, this.length);
  var val = this[offset];
  var mul = 1;
  var i = 0;

  while (++i < byteLength && (mul *= 0x100)) {
    val += this[offset + i] * mul;
  }

  return val;
};

Buffer.prototype.readUIntBE = function readUIntBE(offset, byteLength, noAssert) {
  offset = offset >>> 0;
  byteLength = byteLength >>> 0;

  if (!noAssert) {
    checkOffset(offset, byteLength, this.length);
  }

  var val = this[offset + --byteLength];
  var mul = 1;

  while (byteLength > 0 && (mul *= 0x100)) {
    val += this[offset + --byteLength] * mul;
  }

  return val;
};

Buffer.prototype.readUInt8 = function readUInt8(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 1, this.length);
  return this[offset];
};

Buffer.prototype.readUInt16LE = function readUInt16LE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 2, this.length);
  return this[offset] | this[offset + 1] << 8;
};

Buffer.prototype.readUInt16BE = function readUInt16BE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 2, this.length);
  return this[offset] << 8 | this[offset + 1];
};

Buffer.prototype.readUInt32LE = function readUInt32LE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 4, this.length);
  return (this[offset] | this[offset + 1] << 8 | this[offset + 2] << 16) + this[offset + 3] * 0x1000000;
};

Buffer.prototype.readUInt32BE = function readUInt32BE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 4, this.length);
  return this[offset] * 0x1000000 + (this[offset + 1] << 16 | this[offset + 2] << 8 | this[offset + 3]);
};

Buffer.prototype.readIntLE = function readIntLE(offset, byteLength, noAssert) {
  offset = offset >>> 0;
  byteLength = byteLength >>> 0;
  if (!noAssert) checkOffset(offset, byteLength, this.length);
  var val = this[offset];
  var mul = 1;
  var i = 0;

  while (++i < byteLength && (mul *= 0x100)) {
    val += this[offset + i] * mul;
  }

  mul *= 0x80;
  if (val >= mul) val -= Math.pow(2, 8 * byteLength);
  return val;
};

Buffer.prototype.readIntBE = function readIntBE(offset, byteLength, noAssert) {
  offset = offset >>> 0;
  byteLength = byteLength >>> 0;
  if (!noAssert) checkOffset(offset, byteLength, this.length);
  var i = byteLength;
  var mul = 1;
  var val = this[offset + --i];

  while (i > 0 && (mul *= 0x100)) {
    val += this[offset + --i] * mul;
  }

  mul *= 0x80;
  if (val >= mul) val -= Math.pow(2, 8 * byteLength);
  return val;
};

Buffer.prototype.readInt8 = function readInt8(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 1, this.length);
  if (!(this[offset] & 0x80)) return this[offset];
  return (0xff - this[offset] + 1) * -1;
};

Buffer.prototype.readInt16LE = function readInt16LE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 2, this.length);
  var val = this[offset] | this[offset + 1] << 8;
  return val & 0x8000 ? val | 0xFFFF0000 : val;
};

Buffer.prototype.readInt16BE = function readInt16BE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 2, this.length);
  var val = this[offset + 1] | this[offset] << 8;
  return val & 0x8000 ? val | 0xFFFF0000 : val;
};

Buffer.prototype.readInt32LE = function readInt32LE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 4, this.length);
  return this[offset] | this[offset + 1] << 8 | this[offset + 2] << 16 | this[offset + 3] << 24;
};

Buffer.prototype.readInt32BE = function readInt32BE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 4, this.length);
  return this[offset] << 24 | this[offset + 1] << 16 | this[offset + 2] << 8 | this[offset + 3];
};

Buffer.prototype.readFloatLE = function readFloatLE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 4, this.length);
  return ieee754.read(this, offset, true, 23, 4);
};

Buffer.prototype.readFloatBE = function readFloatBE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 4, this.length);
  return ieee754.read(this, offset, false, 23, 4);
};

Buffer.prototype.readDoubleLE = function readDoubleLE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 8, this.length);
  return ieee754.read(this, offset, true, 52, 8);
};

Buffer.prototype.readDoubleBE = function readDoubleBE(offset, noAssert) {
  offset = offset >>> 0;
  if (!noAssert) checkOffset(offset, 8, this.length);
  return ieee754.read(this, offset, false, 52, 8);
};

function checkInt(buf, value, offset, ext, max, min) {
  if (!Buffer.isBuffer(buf)) throw new TypeError('"buffer" argument must be a Buffer instance');
  if (value > max || value < min) throw new RangeError('"value" argument is out of bounds');
  if (offset + ext > buf.length) throw new RangeError('Index out of range');
}

Buffer.prototype.writeUIntLE = function writeUIntLE(value, offset, byteLength, noAssert) {
  value = +value;
  offset = offset >>> 0;
  byteLength = byteLength >>> 0;

  if (!noAssert) {
    var maxBytes = Math.pow(2, 8 * byteLength) - 1;
    checkInt(this, value, offset, byteLength, maxBytes, 0);
  }

  var mul = 1;
  var i = 0;
  this[offset] = value & 0xFF;

  while (++i < byteLength && (mul *= 0x100)) {
    this[offset + i] = value / mul & 0xFF;
  }

  return offset + byteLength;
};

Buffer.prototype.writeUIntBE = function writeUIntBE(value, offset, byteLength, noAssert) {
  value = +value;
  offset = offset >>> 0;
  byteLength = byteLength >>> 0;

  if (!noAssert) {
    var maxBytes = Math.pow(2, 8 * byteLength) - 1;
    checkInt(this, value, offset, byteLength, maxBytes, 0);
  }

  var i = byteLength - 1;
  var mul = 1;
  this[offset + i] = value & 0xFF;

  while (--i >= 0 && (mul *= 0x100)) {
    this[offset + i] = value / mul & 0xFF;
  }

  return offset + byteLength;
};

Buffer.prototype.writeUInt8 = function writeUInt8(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 1, 0xff, 0);
  this[offset] = value & 0xff;
  return offset + 1;
};

Buffer.prototype.writeUInt16LE = function writeUInt16LE(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0);
  this[offset] = value & 0xff;
  this[offset + 1] = value >>> 8;
  return offset + 2;
};

Buffer.prototype.writeUInt16BE = function writeUInt16BE(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0);
  this[offset] = value >>> 8;
  this[offset + 1] = value & 0xff;
  return offset + 2;
};

Buffer.prototype.writeUInt32LE = function writeUInt32LE(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0);
  this[offset + 3] = value >>> 24;
  this[offset + 2] = value >>> 16;
  this[offset + 1] = value >>> 8;
  this[offset] = value & 0xff;
  return offset + 4;
};

Buffer.prototype.writeUInt32BE = function writeUInt32BE(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0);
  this[offset] = value >>> 24;
  this[offset + 1] = value >>> 16;
  this[offset + 2] = value >>> 8;
  this[offset + 3] = value & 0xff;
  return offset + 4;
};

Buffer.prototype.writeIntLE = function writeIntLE(value, offset, byteLength, noAssert) {
  value = +value;
  offset = offset >>> 0;

  if (!noAssert) {
    var limit = Math.pow(2, 8 * byteLength - 1);
    checkInt(this, value, offset, byteLength, limit - 1, -limit);
  }

  var i = 0;
  var mul = 1;
  var sub = 0;
  this[offset] = value & 0xFF;

  while (++i < byteLength && (mul *= 0x100)) {
    if (value < 0 && sub === 0 && this[offset + i - 1] !== 0) {
      sub = 1;
    }

    this[offset + i] = (value / mul >> 0) - sub & 0xFF;
  }

  return offset + byteLength;
};

Buffer.prototype.writeIntBE = function writeIntBE(value, offset, byteLength, noAssert) {
  value = +value;
  offset = offset >>> 0;

  if (!noAssert) {
    var limit = Math.pow(2, 8 * byteLength - 1);
    checkInt(this, value, offset, byteLength, limit - 1, -limit);
  }

  var i = byteLength - 1;
  var mul = 1;
  var sub = 0;
  this[offset + i] = value & 0xFF;

  while (--i >= 0 && (mul *= 0x100)) {
    if (value < 0 && sub === 0 && this[offset + i + 1] !== 0) {
      sub = 1;
    }

    this[offset + i] = (value / mul >> 0) - sub & 0xFF;
  }

  return offset + byteLength;
};

Buffer.prototype.writeInt8 = function writeInt8(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 1, 0x7f, -0x80);
  if (value < 0) value = 0xff + value + 1;
  this[offset] = value & 0xff;
  return offset + 1;
};

Buffer.prototype.writeInt16LE = function writeInt16LE(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000);
  this[offset] = value & 0xff;
  this[offset + 1] = value >>> 8;
  return offset + 2;
};

Buffer.prototype.writeInt16BE = function writeInt16BE(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000);
  this[offset] = value >>> 8;
  this[offset + 1] = value & 0xff;
  return offset + 2;
};

Buffer.prototype.writeInt32LE = function writeInt32LE(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000);
  this[offset] = value & 0xff;
  this[offset + 1] = value >>> 8;
  this[offset + 2] = value >>> 16;
  this[offset + 3] = value >>> 24;
  return offset + 4;
};

Buffer.prototype.writeInt32BE = function writeInt32BE(value, offset, noAssert) {
  value = +value;
  offset = offset >>> 0;
  if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000);
  if (value < 0) value = 0xffffffff + value + 1;
  this[offset] = value >>> 24;
  this[offset + 1] = value >>> 16;
  this[offset + 2] = value >>> 8;
  this[offset + 3] = value & 0xff;
  return offset + 4;
};

function checkIEEE754(buf, value, offset, ext, max, min) {
  if (offset + ext > buf.length) throw new RangeError('Index out of range');
  if (offset < 0) throw new RangeError('Index out of range');
}

function writeFloat(buf, value, offset, littleEndian, noAssert) {
  value = +value;
  offset = offset >>> 0;

  if (!noAssert) {
    checkIEEE754(buf, value, offset, 4, 3.4028234663852886e+38, -3.4028234663852886e+38);
  }

  ieee754.write(buf, value, offset, littleEndian, 23, 4);
  return offset + 4;
}

Buffer.prototype.writeFloatLE = function writeFloatLE(value, offset, noAssert) {
  return writeFloat(this, value, offset, true, noAssert);
};

Buffer.prototype.writeFloatBE = function writeFloatBE(value, offset, noAssert) {
  return writeFloat(this, value, offset, false, noAssert);
};

function writeDouble(buf, value, offset, littleEndian, noAssert) {
  value = +value;
  offset = offset >>> 0;

  if (!noAssert) {
    checkIEEE754(buf, value, offset, 8, 1.7976931348623157E+308, -1.7976931348623157E+308);
  }

  ieee754.write(buf, value, offset, littleEndian, 52, 8);
  return offset + 8;
}

Buffer.prototype.writeDoubleLE = function writeDoubleLE(value, offset, noAssert) {
  return writeDouble(this, value, offset, true, noAssert);
};

Buffer.prototype.writeDoubleBE = function writeDoubleBE(value, offset, noAssert) {
  return writeDouble(this, value, offset, false, noAssert);
}; // copy(targetBuffer, targetStart=0, sourceStart=0, sourceEnd=buffer.length)


Buffer.prototype.copy = function copy(target, targetStart, start, end) {
  if (!Buffer.isBuffer(target)) throw new TypeError('argument should be a Buffer');
  if (!start) start = 0;
  if (!end && end !== 0) end = this.length;
  if (targetStart >= target.length) targetStart = target.length;
  if (!targetStart) targetStart = 0;
  if (end > 0 && end < start) end = start; // Copy 0 bytes; we're done

  if (end === start) return 0;
  if (target.length === 0 || this.length === 0) return 0; // Fatal error conditions

  if (targetStart < 0) {
    throw new RangeError('targetStart out of bounds');
  }

  if (start < 0 || start >= this.length) throw new RangeError('Index out of range');
  if (end < 0) throw new RangeError('sourceEnd out of bounds'); // Are we oob?

  if (end > this.length) end = this.length;

  if (target.length - targetStart < end - start) {
    end = target.length - targetStart + start;
  }

  var len = end - start;

  if (this === target && typeof Uint8Array.prototype.copyWithin === 'function') {
    // Use built-in when available, missing from IE11
    this.copyWithin(targetStart, start, end);
  } else if (this === target && start < targetStart && targetStart < end) {
    // descending copy from end
    for (var i = len - 1; i >= 0; --i) {
      target[i + targetStart] = this[i + start];
    }
  } else {
    Uint8Array.prototype.set.call(target, this.subarray(start, end), targetStart);
  }

  return len;
}; // Usage:
//    buffer.fill(number[, offset[, end]])
//    buffer.fill(buffer[, offset[, end]])
//    buffer.fill(string[, offset[, end]][, encoding])


Buffer.prototype.fill = function fill(val, start, end, encoding) {
  // Handle string cases:
  if (typeof val === 'string') {
    if (typeof start === 'string') {
      encoding = start;
      start = 0;
      end = this.length;
    } else if (typeof end === 'string') {
      encoding = end;
      end = this.length;
    }

    if (encoding !== undefined && typeof encoding !== 'string') {
      throw new TypeError('encoding must be a string');
    }

    if (typeof encoding === 'string' && !Buffer.isEncoding(encoding)) {
      throw new TypeError('Unknown encoding: ' + encoding);
    }

    if (val.length === 1) {
      var code = val.charCodeAt(0);

      if (encoding === 'utf8' && code < 128 || encoding === 'latin1') {
        // Fast path: If `val` fits into a single byte, use that numeric value.
        val = code;
      }
    }
  } else if (typeof val === 'number') {
    val = val & 255;
  } // Invalid ranges are not set to a default, so can range check early.


  if (start < 0 || this.length < start || this.length < end) {
    throw new RangeError('Out of range index');
  }

  if (end <= start) {
    return this;
  }

  start = start >>> 0;
  end = end === undefined ? this.length : end >>> 0;
  if (!val) val = 0;
  var i;

  if (typeof val === 'number') {
    for (i = start; i < end; ++i) {
      this[i] = val;
    }
  } else {
    var bytes = Buffer.isBuffer(val) ? val : Buffer.from(val, encoding);
    var len = bytes.length;

    if (len === 0) {
      throw new TypeError('The value "' + val + '" is invalid for argument "value"');
    }

    for (i = 0; i < end - start; ++i) {
      this[i + start] = bytes[i % len];
    }
  }

  return this;
}; // HELPER FUNCTIONS
// ================


var INVALID_BASE64_RE = /[^+/0-9A-Za-z-_]/g;

function base64clean(str) {
  // Node takes equal signs as end of the Base64 encoding
  str = str.split('=')[0]; // Node strips out invalid characters like \n and \t from the string, base64-js does not

  str = str.trim().replace(INVALID_BASE64_RE, ''); // Node converts strings with length < 2 to ''

  if (str.length < 2) return ''; // Node allows for non-padded base64 strings (missing trailing ===), base64-js does not

  while (str.length % 4 !== 0) {
    str = str + '=';
  }

  return str;
}

function toHex(n) {
  if (n < 16) return '0' + n.toString(16);
  return n.toString(16);
}

function utf8ToBytes(string, units) {
  units = units || Infinity;
  var codePoint;
  var length = string.length;
  var leadSurrogate = null;
  var bytes = [];

  for (var i = 0; i < length; ++i) {
    codePoint = string.charCodeAt(i); // is surrogate component

    if (codePoint > 0xD7FF && codePoint < 0xE000) {
      // last char was a lead
      if (!leadSurrogate) {
        // no lead yet
        if (codePoint > 0xDBFF) {
          // unexpected trail
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD);
          continue;
        } else if (i + 1 === length) {
          // unpaired lead
          if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD);
          continue;
        } // valid lead


        leadSurrogate = codePoint;
        continue;
      } // 2 leads in a row


      if (codePoint < 0xDC00) {
        if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD);
        leadSurrogate = codePoint;
        continue;
      } // valid surrogate pair


      codePoint = (leadSurrogate - 0xD800 << 10 | codePoint - 0xDC00) + 0x10000;
    } else if (leadSurrogate) {
      // valid bmp char, but last char was a lead
      if ((units -= 3) > -1) bytes.push(0xEF, 0xBF, 0xBD);
    }

    leadSurrogate = null; // encode utf8

    if (codePoint < 0x80) {
      if ((units -= 1) < 0) break;
      bytes.push(codePoint);
    } else if (codePoint < 0x800) {
      if ((units -= 2) < 0) break;
      bytes.push(codePoint >> 0x6 | 0xC0, codePoint & 0x3F | 0x80);
    } else if (codePoint < 0x10000) {
      if ((units -= 3) < 0) break;
      bytes.push(codePoint >> 0xC | 0xE0, codePoint >> 0x6 & 0x3F | 0x80, codePoint & 0x3F | 0x80);
    } else if (codePoint < 0x110000) {
      if ((units -= 4) < 0) break;
      bytes.push(codePoint >> 0x12 | 0xF0, codePoint >> 0xC & 0x3F | 0x80, codePoint >> 0x6 & 0x3F | 0x80, codePoint & 0x3F | 0x80);
    } else {
      throw new Error('Invalid code point');
    }
  }

  return bytes;
}

function asciiToBytes(str) {
  var byteArray = [];

  for (var i = 0; i < str.length; ++i) {
    // Node's code seems to be doing this and not & 0x7F..
    byteArray.push(str.charCodeAt(i) & 0xFF);
  }

  return byteArray;
}

function utf16leToBytes(str, units) {
  var c, hi, lo;
  var byteArray = [];

  for (var i = 0; i < str.length; ++i) {
    if ((units -= 2) < 0) break;
    c = str.charCodeAt(i);
    hi = c >> 8;
    lo = c % 256;
    byteArray.push(lo);
    byteArray.push(hi);
  }

  return byteArray;
}

function base64ToBytes(str) {
  return base64.toByteArray(base64clean(str));
}

function blitBuffer(src, dst, offset, length) {
  for (var i = 0; i < length; ++i) {
    if (i + offset >= dst.length || i >= src.length) break;
    dst[i + offset] = src[i];
  }

  return i;
} // ArrayBuffer or Uint8Array objects from other contexts (i.e. iframes) do not pass
// the `instanceof` check but they should be treated as of that type.
// See: https://github.com/feross/buffer/issues/166


function isInstance(obj, type) {
  return obj instanceof type || obj != null && obj.constructor != null && obj.constructor.name != null && obj.constructor.name === type.name;
}

function numberIsNaN(obj) {
  // For IE11 support
  return obj !== obj; // eslint-disable-line no-self-compare
}