index.cjs

'use strict';

Object.defineProperty(exports, '__esModule', { value: true });

var global$1 = (typeof global !== "undefined" ? global :
            typeof self !== "undefined" ? self :
            typeof window !== "undefined" ? window : {});

var lookup = [];
var revLookup = [];
var Arr = typeof Uint8Array !== 'undefined' ? Uint8Array : Array;
var inited = false;
function init () {
  inited = true;
  var code = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
  for (var i = 0, len = code.length; i < len; ++i) {
    lookup[i] = code[i];
    revLookup[code.charCodeAt(i)] = i;
  }

  revLookup['-'.charCodeAt(0)] = 62;
  revLookup['_'.charCodeAt(0)] = 63;
}

function toByteArray (b64) {
  if (!inited) {
    init();
  }
  var i, j, l, tmp, placeHolders, arr;
  var len = b64.length;

  if (len % 4 > 0) {
    throw new Error('Invalid string. Length must be a multiple of 4')
  }

  // the number of equal signs (place holders)
  // if there are two placeholders, than the two characters before it
  // represent one byte
  // if there is only one, then the three characters before it represent 2 bytes
  // this is just a cheap hack to not do indexOf twice
  placeHolders = b64[len - 2] === '=' ? 2 : b64[len - 1] === '=' ? 1 : 0;

  // base64 is 4/3 + up to two characters of the original data
  arr = new Arr(len * 3 / 4 - placeHolders);

  // if there are placeholders, only get up to the last complete 4 chars
  l = placeHolders > 0 ? len - 4 : len;

  var L = 0;

  for (i = 0, j = 0; i < l; i += 4, j += 3) {
    tmp = (revLookup[b64.charCodeAt(i)] << 18) | (revLookup[b64.charCodeAt(i + 1)] << 12) | (revLookup[b64.charCodeAt(i + 2)] << 6) | revLookup[b64.charCodeAt(i + 3)];
    arr[L++] = (tmp >> 16) & 0xFF;
    arr[L++] = (tmp >> 8) & 0xFF;
    arr[L++] = tmp & 0xFF;
  }

  if (placeHolders === 2) {
    tmp = (revLookup[b64.charCodeAt(i)] << 2) | (revLookup[b64.charCodeAt(i + 1)] >> 4);
    arr[L++] = tmp & 0xFF;
  } else if (placeHolders === 1) {
    tmp = (revLookup[b64.charCodeAt(i)] << 10) | (revLookup[b64.charCodeAt(i + 1)] << 4) | (revLookup[b64.charCodeAt(i + 2)] >> 2);
    arr[L++] = (tmp >> 8) & 0xFF;
    arr[L++] = tmp & 0xFF;
  }

  return arr
}

function tripletToBase64 (num) {
  return lookup[num >> 18 & 0x3F] + lookup[num >> 12 & 0x3F] + lookup[num >> 6 & 0x3F] + lookup[num & 0x3F]
}

function encodeChunk (uint8, start, end) {
  var tmp;
  var output = [];
  for (var i = start; i < end; i += 3) {
    tmp = (uint8[i] << 16) + (uint8[i + 1] << 8) + (uint8[i + 2]);
    output.push(tripletToBase64(tmp));
  }
  return output.join('')
}

function fromByteArray (uint8) {
  if (!inited) {
    init();
  }
  var tmp;
  var len = uint8.length;
  var extraBytes = len % 3; // if we have 1 byte left, pad 2 bytes
  var output = '';
  var parts = [];
  var maxChunkLength = 16383; // must be multiple of 3

  // go through the array every three bytes, we'll deal with trailing stuff later
  for (var i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
    parts.push(encodeChunk(uint8, i, (i + maxChunkLength) > len2 ? len2 : (i + maxChunkLength)));
  }

  // pad the end with zeros, but make sure to not forget the extra bytes
  if (extraBytes === 1) {
    tmp = uint8[len - 1];
    output += lookup[tmp >> 2];
    output += lookup[(tmp << 4) & 0x3F];
    output += '==';
  } else if (extraBytes === 2) {
    tmp = (uint8[len - 2] << 8) + (uint8[len - 1]);
    output += lookup[tmp >> 10];
    output += lookup[(tmp >> 4) & 0x3F];
    output += lookup[(tmp << 2) & 0x3F];
    output += '=';
  }

  parts.push(output);

  return parts.join('')
}

function read (buffer, offset, isLE, mLen, nBytes) {
  var e, m;
  var eLen = nBytes * 8 - mLen - 1;
  var eMax = (1 << eLen) - 1;
  var eBias = eMax >> 1;
  var nBits = -7;
  var i = isLE ? (nBytes - 1) : 0;
  var d = isLE ? -1 : 1;
  var s = buffer[offset + i];

  i += d;

  e = s & ((1 << (-nBits)) - 1);
  s >>= (-nBits);
  nBits += eLen;
  for (; nBits > 0; e = e * 256 + buffer[offset + i], i += d, nBits -= 8) {}

  m = e & ((1 << (-nBits)) - 1);
  e >>= (-nBits);
  nBits += mLen;
  for (; nBits > 0; m = m * 256 + buffer[offset + i], i += d, nBits -= 8) {}

  if (e === 0) {
    e = 1 - eBias;
  } else if (e === eMax) {
    return m ? NaN : ((s ? -1 : 1) * Infinity)
  } else {
    m = m + Math.pow(2, mLen);
    e = e - eBias;
  }
  return (s ? -1 : 1) * m * Math.pow(2, e - mLen)
}

function write (buffer, value, offset, isLE, mLen, nBytes) {
  var e, m, c;
  var eLen = nBytes * 8 - mLen - 1;
  var eMax = (1 << eLen) - 1;
  var eBias = eMax >> 1;
  var rt = (mLen === 23 ? Math.pow(2, -24) - Math.pow(2, -77) : 0);
  var i = isLE ? 0 : (nBytes - 1);
  var d = isLE ? 1 : -1;
  var s = value < 0 || (value === 0 && 1 / value < 0) ? 1 : 0;

  value = Math.abs(value);

  if (isNaN(value) || value === Infinity) {
    m = isNaN(value) ? 1 : 0;
    e = eMax;
  } else {
    e = Math.floor(Math.log(value) / Math.LN2);
    if (value * (c = Math.pow(2, -e)) < 1) {
      e--;
      c *= 2;
    }
    if (e + eBias >= 1) {
      value += rt / c;
    } else {
      value += rt * Math.pow(2, 1 - eBias);
    }
    if (value * c >= 2) {
      e++;
      c /= 2;
    }

    if (e + eBias >= eMax) {
      m = 0;
      e = eMax;
    } else if (e + eBias >= 1) {
      m = (value * c - 1) * Math.pow(2, mLen);
      e = e + eBias;
    } else {
      m = value * Math.pow(2, eBias - 1) * Math.pow(2, mLen);
      e = 0;
    }
  }

  for (; mLen >= 8; buffer[offset + i] = m & 0xff, i += d, m /= 256, mLen -= 8) {}

  e = (e << mLen) | m;
  eLen += mLen;
  for (; eLen > 0; buffer[offset + i] = e & 0xff, i += d, e /= 256, eLen -= 8) {}

  buffer[offset + i - d] |= s * 128;
}

var toString = {}.toString;

var isArray$1 = Array.isArray || function (arr) {
  return toString.call(arr) == '[object Array]';
};

var INSPECT_MAX_BYTES = 50;

/**
 * If `Buffer.TYPED_ARRAY_SUPPORT`:
 *   === true    Use Uint8Array implementation (fastest)
 *   === false   Use 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+.
 *
 * Due to various browser bugs, sometimes the Object implementation will be used even
 * when the browser supports typed arrays.
 *
 * Note:
 *
 *   - Firefox 4-29 lacks support for adding new properties to `Uint8Array` instances,
 *     See: https://bugzilla.mozilla.org/show_bug.cgi?id=695438.
 *
 *   - Chrome 9-10 is missing the `TypedArray.prototype.subarray` function.
 *
 *   - IE10 has a broken `TypedArray.prototype.subarray` function which returns arrays of
 *     incorrect length in some situations.

 * We detect these buggy browsers and set `Buffer.TYPED_ARRAY_SUPPORT` to `false` so they
 * get the Object implementation, which is slower but behaves correctly.
 */
Buffer.TYPED_ARRAY_SUPPORT = global$1.TYPED_ARRAY_SUPPORT !== undefined
  ? global$1.TYPED_ARRAY_SUPPORT
  : true;

function kMaxLength () {
  return Buffer.TYPED_ARRAY_SUPPORT
    ? 0x7fffffff
    : 0x3fffffff
}

function createBuffer (that, length) {
  if (kMaxLength() < length) {
    throw new RangeError('Invalid typed array length')
  }
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    // Return an augmented `Uint8Array` instance, for best performance
    that = new Uint8Array(length);
    that.__proto__ = Buffer.prototype;
  } else {
    // Fallback: Return an object instance of the Buffer class
    if (that === null) {
      that = new Buffer(length);
    }
    that.length = length;
  }

  return that
}

/**
 * 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) {
  if (!Buffer.TYPED_ARRAY_SUPPORT && !(this instanceof Buffer)) {
    return new Buffer(arg, encodingOrOffset, length)
  }

  // Common case.
  if (typeof arg === 'number') {
    if (typeof encodingOrOffset === 'string') {
      throw new Error(
        'If encoding is specified then the first argument must be a string'
      )
    }
    return allocUnsafe(this, arg)
  }
  return from(this, arg, encodingOrOffset, length)
}

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

// TODO: Legacy, not needed anymore. Remove in next major version.
Buffer._augment = function (arr) {
  arr.__proto__ = Buffer.prototype;
  return arr
};

function from (that, value, encodingOrOffset, length) {
  if (typeof value === 'number') {
    throw new TypeError('"value" argument must not be a number')
  }

  if (typeof ArrayBuffer !== 'undefined' && value instanceof ArrayBuffer) {
    return fromArrayBuffer(that, value, encodingOrOffset, length)
  }

  if (typeof value === 'string') {
    return fromString(that, value, encodingOrOffset)
  }

  return fromObject(that, 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(null, value, encodingOrOffset, length)
};

if (Buffer.TYPED_ARRAY_SUPPORT) {
  Buffer.prototype.__proto__ = Uint8Array.prototype;
  Buffer.__proto__ = Uint8Array;
}

function assertSize (size) {
  if (typeof size !== 'number') {
    throw new TypeError('"size" argument must be a number')
  } else if (size < 0) {
    throw new RangeError('"size" argument must not be negative')
  }
}

function alloc (that, size, fill, encoding) {
  assertSize(size);
  if (size <= 0) {
    return createBuffer(that, 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(that, size).fill(fill, encoding)
      : createBuffer(that, size).fill(fill)
  }
  return createBuffer(that, size)
}

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

function allocUnsafe (that, size) {
  assertSize(size);
  that = createBuffer(that, size < 0 ? 0 : checked(size) | 0);
  if (!Buffer.TYPED_ARRAY_SUPPORT) {
    for (var i = 0; i < size; ++i) {
      that[i] = 0;
    }
  }
  return that
}

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

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

  if (!Buffer.isEncoding(encoding)) {
    throw new TypeError('"encoding" must be a valid string encoding')
  }

  var length = byteLength(string, encoding) | 0;
  that = createBuffer(that, length);

  var actual = that.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')
    that = that.slice(0, actual);
  }

  return that
}

function fromArrayLike (that, array) {
  var length = array.length < 0 ? 0 : checked(array.length) | 0;
  that = createBuffer(that, length);
  for (var i = 0; i < length; i += 1) {
    that[i] = array[i] & 255;
  }
  return that
}

function fromArrayBuffer (that, array, byteOffset, length) {
  array.byteLength; // this throws if `array` is not a valid ArrayBuffer

  if (byteOffset < 0 || array.byteLength < byteOffset) {
    throw new RangeError('\'offset\' is out of bounds')
  }

  if (array.byteLength < byteOffset + (length || 0)) {
    throw new RangeError('\'length\' is out of bounds')
  }

  if (byteOffset === undefined && length === undefined) {
    array = new Uint8Array(array);
  } else if (length === undefined) {
    array = new Uint8Array(array, byteOffset);
  } else {
    array = new Uint8Array(array, byteOffset, length);
  }

  if (Buffer.TYPED_ARRAY_SUPPORT) {
    // Return an augmented `Uint8Array` instance, for best performance
    that = array;
    that.__proto__ = Buffer.prototype;
  } else {
    // Fallback: Return an object instance of the Buffer class
    that = fromArrayLike(that, array);
  }
  return that
}

function fromObject (that, obj) {
  if (internalIsBuffer(obj)) {
    var len = checked(obj.length) | 0;
    that = createBuffer(that, len);

    if (that.length === 0) {
      return that
    }

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

  if (obj) {
    if ((typeof ArrayBuffer !== 'undefined' &&
        obj.buffer instanceof ArrayBuffer) || 'length' in obj) {
      if (typeof obj.length !== 'number' || isnan(obj.length)) {
        return createBuffer(that, 0)
      }
      return fromArrayLike(that, obj)
    }

    if (obj.type === 'Buffer' && isArray$1(obj.data)) {
      return fromArrayLike(that, obj.data)
    }
  }

  throw new TypeError('First argument must be a string, Buffer, ArrayBuffer, Array, or array-like object.')
}

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

Buffer.compare = function compare (a, b) {
  if (!internalIsBuffer(a) || !internalIsBuffer(b)) {
    throw new TypeError('Arguments must be Buffers')
  }

  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 (!isArray$1(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 (!internalIsBuffer(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 (internalIsBuffer(string)) {
    return string.length
  }
  if (typeof ArrayBuffer !== 'undefined' && typeof ArrayBuffer.isView === 'function' &&
      (ArrayBuffer.isView(string) || string instanceof ArrayBuffer)) {
    return string.byteLength
  }
  if (typeof string !== 'string') {
    string = '' + string;
  }

  var len = string.length;
  if (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':
      case undefined:
        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 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;
    }
  }
}

// The property is used by `Buffer.isBuffer` and `is-buffer` (in Safari 5-7) to detect
// Buffer instances.
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 | 0;
  if (length === 0) return ''
  if (arguments.length === 0) return utf8Slice(this, 0, length)
  return slowToString.apply(this, arguments)
};

Buffer.prototype.equals = function equals (b) {
  if (!internalIsBuffer(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 = INSPECT_MAX_BYTES;
  if (this.length > 0) {
    str = this.toString('hex', 0, max).match(/.{2}/g).join(' ');
    if (this.length > max) str += ' ... ';
  }
  return '<Buffer ' + str + '>'
};

Buffer.prototype.compare = function compare (target, start, end, thisStart, thisEnd) {
  if (!internalIsBuffer(target)) {
    throw new TypeError('Argument must be a Buffer')
  }

  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 (isNaN(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 (internalIsBuffer(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 (Buffer.TYPED_ARRAY_SUPPORT &&
        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;
    }
  }

  // must be an even number of digits
  var strLen = string.length;
  if (strLen % 2 !== 0) throw new TypeError('Invalid hex string')

  if (length > strLen / 2) {
    length = strLen / 2;
  }
  for (var i = 0; i < length; ++i) {
    var parsed = parseInt(string.substr(i * 2, 2), 16);
    if (isNaN(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;
    }
  // legacy write(string, encoding, offset, length) - remove in v0.13
  } 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 fromByteArray(buf)
  } else {
    return 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;
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    newBuf = this.subarray(start, end);
    newBuf.__proto__ = Buffer.prototype;
  } else {
    var sliceLen = end - start;
    newBuf = new Buffer(sliceLen, undefined);
    for (var i = 0; i < sliceLen; ++i) {
      newBuf[i] = this[i + start];
    }
  }

  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) {
  if (!noAssert) checkOffset(offset, 1, this.length);
  return this[offset]
};

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

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

Buffer.prototype.readUInt32LE = function readUInt32LE (offset, noAssert) {
  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) {
  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) {
  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) {
  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) {
  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) {
  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) {
  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) {
  if (!noAssert) checkOffset(offset, 4, this.length);
  return read(this, offset, true, 23, 4)
};

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

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

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

function checkInt (buf, value, offset, ext, max, min) {
  if (!internalIsBuffer(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);
  if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value);
  this[offset] = (value & 0xff);
  return offset + 1
};

function objectWriteUInt16 (buf, value, offset, littleEndian) {
  if (value < 0) value = 0xffff + value + 1;
  for (var i = 0, j = Math.min(buf.length - offset, 2); i < j; ++i) {
    buf[offset + i] = (value & (0xff << (8 * (littleEndian ? i : 1 - i)))) >>>
      (littleEndian ? i : 1 - i) * 8;
  }
}

Buffer.prototype.writeUInt16LE = function writeUInt16LE (value, offset, noAssert) {
  value = +value;
  offset = offset | 0;
  if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0);
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value & 0xff);
    this[offset + 1] = (value >>> 8);
  } else {
    objectWriteUInt16(this, value, offset, true);
  }
  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);
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 8);
    this[offset + 1] = (value & 0xff);
  } else {
    objectWriteUInt16(this, value, offset, false);
  }
  return offset + 2
};

function objectWriteUInt32 (buf, value, offset, littleEndian) {
  if (value < 0) value = 0xffffffff + value + 1;
  for (var i = 0, j = Math.min(buf.length - offset, 4); i < j; ++i) {
    buf[offset + i] = (value >>> (littleEndian ? i : 3 - i) * 8) & 0xff;
  }
}

Buffer.prototype.writeUInt32LE = function writeUInt32LE (value, offset, noAssert) {
  value = +value;
  offset = offset | 0;
  if (!noAssert) checkInt(this, value, offset, 4, 0xffffffff, 0);
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset + 3] = (value >>> 24);
    this[offset + 2] = (value >>> 16);
    this[offset + 1] = (value >>> 8);
    this[offset] = (value & 0xff);
  } else {
    objectWriteUInt32(this, value, offset, true);
  }
  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);
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 24);
    this[offset + 1] = (value >>> 16);
    this[offset + 2] = (value >>> 8);
    this[offset + 3] = (value & 0xff);
  } else {
    objectWriteUInt32(this, value, offset, false);
  }
  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 (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value);
  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);
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value & 0xff);
    this[offset + 1] = (value >>> 8);
  } else {
    objectWriteUInt16(this, value, offset, true);
  }
  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);
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 8);
    this[offset + 1] = (value & 0xff);
  } else {
    objectWriteUInt16(this, value, offset, false);
  }
  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);
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value & 0xff);
    this[offset + 1] = (value >>> 8);
    this[offset + 2] = (value >>> 16);
    this[offset + 3] = (value >>> 24);
  } else {
    objectWriteUInt32(this, value, offset, true);
  }
  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;
  if (Buffer.TYPED_ARRAY_SUPPORT) {
    this[offset] = (value >>> 24);
    this[offset + 1] = (value >>> 16);
    this[offset + 2] = (value >>> 8);
    this[offset + 3] = (value & 0xff);
  } else {
    objectWriteUInt32(this, value, offset, false);
  }
  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) {
  if (!noAssert) {
    checkIEEE754(buf, value, offset, 4);
  }
  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) {
  if (!noAssert) {
    checkIEEE754(buf, value, offset, 8);
  }
  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 (!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('sourceStart out of bounds')
  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;
  var i;

  if (this === target && start < targetStart && targetStart < end) {
    // descending copy from end
    for (i = len - 1; i >= 0; --i) {
      target[i + targetStart] = this[i + start];
    }
  } else if (len < 1000 || !Buffer.TYPED_ARRAY_SUPPORT) {
    // ascending copy from start
    for (i = 0; i < len; ++i) {
      target[i + targetStart] = this[i + start];
    }
  } else {
    Uint8Array.prototype.set.call(
      target,
      this.subarray(start, start + len),
      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 (val.length === 1) {
      var code = val.charCodeAt(0);
      if (code < 256) {
        val = code;
      }
    }
    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)
    }
  } 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 = internalIsBuffer(val)
      ? val
      : utf8ToBytes(new Buffer(val, encoding).toString());
    var len = bytes.length;
    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 strips out invalid characters like \n and \t from the string, base64-js does not
  str = stringtrim(str).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 stringtrim (str) {
  if (str.trim) return str.trim()
  return str.replace(/^\s+|\s+$/g, '')
}

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 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
}

function isnan (val) {
  return val !== val // eslint-disable-line no-self-compare
}


// the following is from is-buffer, also by Feross Aboukhadijeh and with same lisence
// The _isBuffer check is for Safari 5-7 support, because it's missing
// Object.prototype.constructor. Remove this eventually
function isBuffer(obj) {
  return obj != null && (!!obj._isBuffer || isFastBuffer(obj) || isSlowBuffer(obj))
}

function isFastBuffer (obj) {
  return !!obj.constructor && typeof obj.constructor.isBuffer === 'function' && obj.constructor.isBuffer(obj)
}

// For Node v0.10 support. Remove this eventually.
function isSlowBuffer (obj) {
  return typeof obj.readFloatLE === 'function' && typeof obj.slice === 'function' && isFastBuffer(obj.slice(0, 0))
}

var domain;

// This constructor is used to store event handlers. Instantiating this is
// faster than explicitly calling `Object.create(null)` to get a "clean" empty
// object (tested with v8 v4.9).
function EventHandlers() {}
EventHandlers.prototype = Object.create(null);

function EventEmitter() {
  EventEmitter.init.call(this);
}

// nodejs oddity
// require('events') === require('events').EventEmitter
EventEmitter.EventEmitter = EventEmitter;

EventEmitter.usingDomains = false;

EventEmitter.prototype.domain = undefined;
EventEmitter.prototype._events = undefined;
EventEmitter.prototype._maxListeners = undefined;

// By default EventEmitters will print a warning if more than 10 listeners are
// added to it. This is a useful default which helps finding memory leaks.
EventEmitter.defaultMaxListeners = 10;

EventEmitter.init = function() {
  this.domain = null;
  if (EventEmitter.usingDomains) {
    // if there is an active domain, then attach to it.
    if (domain.active ) ;
  }

  if (!this._events || this._events === Object.getPrototypeOf(this)._events) {
    this._events = new EventHandlers();
    this._eventsCount = 0;
  }

  this._maxListeners = this._maxListeners || undefined;
};

// Obviously not all Emitters should be limited to 10. This function allows
// that to be increased. Set to zero for unlimited.
EventEmitter.prototype.setMaxListeners = function setMaxListeners(n) {
  if (typeof n !== 'number' || n < 0 || isNaN(n))
    throw new TypeError('"n" argument must be a positive number');
  this._maxListeners = n;
  return this;
};

function $getMaxListeners(that) {
  if (that._maxListeners === undefined)
    return EventEmitter.defaultMaxListeners;
  return that._maxListeners;
}

EventEmitter.prototype.getMaxListeners = function getMaxListeners() {
  return $getMaxListeners(this);
};

// These standalone emit* functions are used to optimize calling of event
// handlers for fast cases because emit() itself often has a variable number of
// arguments and can be deoptimized because of that. These functions always have
// the same number of arguments and thus do not get deoptimized, so the code
// inside them can execute faster.
function emitNone(handler, isFn, self) {
  if (isFn)
    handler.call(self);
  else {
    var len = handler.length;
    var listeners = arrayClone(handler, len);
    for (var i = 0; i < len; ++i)
      listeners[i].call(self);
  }
}
function emitOne(handler, isFn, self, arg1) {
  if (isFn)
    handler.call(self, arg1);
  else {
    var len = handler.length;
    var listeners = arrayClone(handler, len);
    for (var i = 0; i < len; ++i)
      listeners[i].call(self, arg1);
  }
}
function emitTwo(handler, isFn, self, arg1, arg2) {
  if (isFn)
    handler.call(self, arg1, arg2);
  else {
    var len = handler.length;
    var listeners = arrayClone(handler, len);
    for (var i = 0; i < len; ++i)
      listeners[i].call(self, arg1, arg2);
  }
}
function emitThree(handler, isFn, self, arg1, arg2, arg3) {
  if (isFn)
    handler.call(self, arg1, arg2, arg3);
  else {
    var len = handler.length;
    var listeners = arrayClone(handler, len);
    for (var i = 0; i < len; ++i)
      listeners[i].call(self, arg1, arg2, arg3);
  }
}

function emitMany(handler, isFn, self, args) {
  if (isFn)
    handler.apply(self, args);
  else {
    var len = handler.length;
    var listeners = arrayClone(handler, len);
    for (var i = 0; i < len; ++i)
      listeners[i].apply(self, args);
  }
}

EventEmitter.prototype.emit = function emit(type) {
  var er, handler, len, args, i, events, domain;
  var doError = (type === 'error');

  events = this._events;
  if (events)
    doError = (doError && events.error == null);
  else if (!doError)
    return false;

  domain = this.domain;

  // If there is no 'error' event listener then throw.
  if (doError) {
    er = arguments[1];
    if (domain) {
      if (!er)
        er = new Error('Uncaught, unspecified "error" event');
      er.domainEmitter = this;
      er.domain = domain;
      er.domainThrown = false;
      domain.emit('error', er);
    } else if (er instanceof Error) {
      throw er; // Unhandled 'error' event
    } else {
      // At least give some kind of context to the user
      var err = new Error('Uncaught, unspecified "error" event. (' + er + ')');
      err.context = er;
      throw err;
    }
    return false;
  }

  handler = events[type];

  if (!handler)
    return false;

  var isFn = typeof handler === 'function';
  len = arguments.length;
  switch (len) {
    // fast cases
    case 1:
      emitNone(handler, isFn, this);
      break;
    case 2:
      emitOne(handler, isFn, this, arguments[1]);
      break;
    case 3:
      emitTwo(handler, isFn, this, arguments[1], arguments[2]);
      break;
    case 4:
      emitThree(handler, isFn, this, arguments[1], arguments[2], arguments[3]);
      break;
    // slower
    default:
      args = new Array(len - 1);
      for (i = 1; i < len; i++)
        args[i - 1] = arguments[i];
      emitMany(handler, isFn, this, args);
  }

  return true;
};

function _addListener(target, type, listener, prepend) {
  var m;
  var events;
  var existing;

  if (typeof listener !== 'function')
    throw new TypeError('"listener" argument must be a function');

  events = target._events;
  if (!events) {
    events = target._events = new EventHandlers();
    target._eventsCount = 0;
  } else {
    // To avoid recursion in the case that type === "newListener"! Before
    // adding it to the listeners, first emit "newListener".
    if (events.newListener) {
      target.emit('newListener', type,
                  listener.listener ? listener.listener : listener);

      // Re-assign `events` because a newListener handler could have caused the
      // this._events to be assigned to a new object
      events = target._events;
    }
    existing = events[type];
  }

  if (!existing) {
    // Optimize the case of one listener. Don't need the extra array object.
    existing = events[type] = listener;
    ++target._eventsCount;
  } else {
    if (typeof existing === 'function') {
      // Adding the second element, need to change to array.
      existing = events[type] = prepend ? [listener, existing] :
                                          [existing, listener];
    } else {
      // If we've already got an array, just append.
      if (prepend) {
        existing.unshift(listener);
      } else {
        existing.push(listener);
      }
    }

    // Check for listener leak
    if (!existing.warned) {
      m = $getMaxListeners(target);
      if (m && m > 0 && existing.length > m) {
        existing.warned = true;
        var w = new Error('Possible EventEmitter memory leak detected. ' +
                            existing.length + ' ' + type + ' listeners added. ' +
                            'Use emitter.setMaxListeners() to increase limit');
        w.name = 'MaxListenersExceededWarning';
        w.emitter = target;
        w.type = type;
        w.count = existing.length;
        emitWarning(w);
      }
    }
  }

  return target;
}
function emitWarning(e) {
  typeof console.warn === 'function' ? console.warn(e) : console.log(e);
}
EventEmitter.prototype.addListener = function addListener(type, listener) {
  return _addListener(this, type, listener, false);
};

EventEmitter.prototype.on = EventEmitter.prototype.addListener;

EventEmitter.prototype.prependListener =
    function prependListener(type, listener) {
      return _addListener(this, type, listener, true);
    };

function _onceWrap(target, type, listener) {
  var fired = false;
  function g() {
    target.removeListener(type, g);
    if (!fired) {
      fired = true;
      listener.apply(target, arguments);
    }
  }
  g.listener = listener;
  return g;
}

EventEmitter.prototype.once = function once(type, listener) {
  if (typeof listener !== 'function')
    throw new TypeError('"listener" argument must be a function');
  this.on(type, _onceWrap(this, type, listener));
  return this;
};

EventEmitter.prototype.prependOnceListener =
    function prependOnceListener(type, listener) {
      if (typeof listener !== 'function')
        throw new TypeError('"listener" argument must be a function');
      this.prependListener(type, _onceWrap(this, type, listener));
      return this;
    };

// emits a 'removeListener' event iff the listener was removed
EventEmitter.prototype.removeListener =
    function removeListener(type, listener) {
      var list, events, position, i, originalListener;

      if (typeof listener !== 'function')
        throw new TypeError('"listener" argument must be a function');

      events = this._events;
      if (!events)
        return this;

      list = events[type];
      if (!list)
        return this;

      if (list === listener || (list.listener && list.listener === listener)) {
        if (--this._eventsCount === 0)
          this._events = new EventHandlers();
        else {
          delete events[type];
          if (events.removeListener)
            this.emit('removeListener', type, list.listener || listener);
        }
      } else if (typeof list !== 'function') {
        position = -1;

        for (i = list.length; i-- > 0;) {
          if (list[i] === listener ||
              (list[i].listener && list[i].listener === listener)) {
            originalListener = list[i].listener;
            position = i;
            break;
          }
        }

        if (position < 0)
          return this;

        if (list.length === 1) {
          list[0] = undefined;
          if (--this._eventsCount === 0) {
            this._events = new EventHandlers();
            return this;
          } else {
            delete events[type];
          }
        } else {
          spliceOne(list, position);
        }

        if (events.removeListener)
          this.emit('removeListener', type, originalListener || listener);
      }

      return this;
    };

EventEmitter.prototype.removeAllListeners =
    function removeAllListeners(type) {
      var listeners, events;

      events = this._events;
      if (!events)
        return this;

      // not listening for removeListener, no need to emit
      if (!events.removeListener) {
        if (arguments.length === 0) {
          this._events = new EventHandlers();
          this._eventsCount = 0;
        } else if (events[type]) {
          if (--this._eventsCount === 0)
            this._events = new EventHandlers();
          else
            delete events[type];
        }
        return this;
      }

      // emit removeListener for all listeners on all events
      if (arguments.length === 0) {
        var keys = Object.keys(events);
        for (var i = 0, key; i < keys.length; ++i) {
          key = keys[i];
          if (key === 'removeListener') continue;
          this.removeAllListeners(key);
        }
        this.removeAllListeners('removeListener');
        this._events = new EventHandlers();
        this._eventsCount = 0;
        return this;
      }

      listeners = events[type];

      if (typeof listeners === 'function') {
        this.removeListener(type, listeners);
      } else if (listeners) {
        // LIFO order
        do {
          this.removeListener(type, listeners[listeners.length - 1]);
        } while (listeners[0]);
      }

      return this;
    };

EventEmitter.prototype.listeners = function listeners(type) {
  var evlistener;
  var ret;
  var events = this._events;

  if (!events)
    ret = [];
  else {
    evlistener = events[type];
    if (!evlistener)
      ret = [];
    else if (typeof evlistener === 'function')
      ret = [evlistener.listener || evlistener];
    else
      ret = unwrapListeners(evlistener);
  }

  return ret;
};

EventEmitter.listenerCount = function(emitter, type) {
  if (typeof emitter.listenerCount === 'function') {
    return emitter.listenerCount(type);
  } else {
    return listenerCount$1.call(emitter, type);
  }
};

EventEmitter.prototype.listenerCount = listenerCount$1;
function listenerCount$1(type) {
  var events = this._events;

  if (events) {
    var evlistener = events[type];

    if (typeof evlistener === 'function') {
      return 1;
    } else if (evlistener) {
      return evlistener.length;
    }
  }

  return 0;
}

EventEmitter.prototype.eventNames = function eventNames() {
  return this._eventsCount > 0 ? Reflect.ownKeys(this._events) : [];
};

// About 1.5x faster than the two-arg version of Array#splice().
function spliceOne(list, index) {
  for (var i = index, k = i + 1, n = list.length; k < n; i += 1, k += 1)
    list[i] = list[k];
  list.pop();
}

function arrayClone(arr, i) {
  var copy = new Array(i);
  while (i--)
    copy[i] = arr[i];
  return copy;
}

function unwrapListeners(arr) {
  var ret = new Array(arr.length);
  for (var i = 0; i < ret.length; ++i) {
    ret[i] = arr[i].listener || arr[i];
  }
  return ret;
}

// shim for using process in browser
// based off https://github.com/defunctzombie/node-process/blob/master/browser.js

function defaultSetTimout() {
    throw new Error('setTimeout has not been defined');
}
function defaultClearTimeout () {
    throw new Error('clearTimeout has not been defined');
}
var cachedSetTimeout = defaultSetTimout;
var cachedClearTimeout = defaultClearTimeout;
if (typeof global$1.setTimeout === 'function') {
    cachedSetTimeout = setTimeout;
}
if (typeof global$1.clearTimeout === 'function') {
    cachedClearTimeout = clearTimeout;
}

function runTimeout(fun) {
    if (cachedSetTimeout === setTimeout) {
        //normal enviroments in sane situations
        return setTimeout(fun, 0);
    }
    // if setTimeout wasn't available but was latter defined
    if ((cachedSetTimeout === defaultSetTimout || !cachedSetTimeout) && setTimeout) {
        cachedSetTimeout = setTimeout;
        return setTimeout(fun, 0);
    }
    try {
        // when when somebody has screwed with setTimeout but no I.E. maddness
        return cachedSetTimeout(fun, 0);
    } catch(e){
        try {
            // When we are in I.E. but the script has been evaled so I.E. doesn't trust the global object when called normally
            return cachedSetTimeout.call(null, fun, 0);
        } catch(e){
            // same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error
            return cachedSetTimeout.call(this, fun, 0);
        }
    }


}
function runClearTimeout(marker) {
    if (cachedClearTimeout === clearTimeout) {
        //normal enviroments in sane situations
        return clearTimeout(marker);
    }
    // if clearTimeout wasn't available but was latter defined
    if ((cachedClearTimeout === defaultClearTimeout || !cachedClearTimeout) && clearTimeout) {
        cachedClearTimeout = clearTimeout;
        return clearTimeout(marker);
    }
    try {
        // when when somebody has screwed with setTimeout but no I.E. maddness
        return cachedClearTimeout(marker);
    } catch (e){
        try {
            // When we are in I.E. but the script has been evaled so I.E. doesn't  trust the global object when called normally
            return cachedClearTimeout.call(null, marker);
        } catch (e){
            // same as above but when it's a version of I.E. that must have the global object for 'this', hopfully our context correct otherwise it will throw a global error.
            // Some versions of I.E. have different rules for clearTimeout vs setTimeout
            return cachedClearTimeout.call(this, marker);
        }
    }



}
var queue = [];
var draining = false;
var currentQueue;
var queueIndex = -1;

function cleanUpNextTick() {
    if (!draining || !currentQueue) {
        return;
    }
    draining = false;
    if (currentQueue.length) {
        queue = currentQueue.concat(queue);
    } else {
        queueIndex = -1;
    }
    if (queue.length) {
        drainQueue();
    }
}

function drainQueue() {
    if (draining) {
        return;
    }
    var timeout = runTimeout(cleanUpNextTick);
    draining = true;

    var len = queue.length;
    while(len) {
        currentQueue = queue;
        queue = [];
        while (++queueIndex < len) {
            if (currentQueue) {
                currentQueue[queueIndex].run();
            }
        }
        queueIndex = -1;
        len = queue.length;
    }
    currentQueue = null;
    draining = false;
    runClearTimeout(timeout);
}
function nextTick(fun) {
    var args = new Array(arguments.length - 1);
    if (arguments.length > 1) {
        for (var i = 1; i < arguments.length; i++) {
            args[i - 1] = arguments[i];
        }
    }
    queue.push(new Item(fun, args));
    if (queue.length === 1 && !draining) {
        runTimeout(drainQueue);
    }
}
// v8 likes predictible objects
function Item(fun, array) {
    this.fun = fun;
    this.array = array;
}
Item.prototype.run = function () {
    this.fun.apply(null, this.array);
};

// from https://github.com/kumavis/browser-process-hrtime/blob/master/index.js
var performance = global$1.performance || {};
performance.now        ||
  performance.mozNow     ||
  performance.msNow      ||
  performance.oNow       ||
  performance.webkitNow  ||
  function(){ return (new Date()).getTime() };

var inherits;
if (typeof Object.create === 'function'){
  inherits = function inherits(ctor, superCtor) {
    // implementation from standard node.js 'util' module
    ctor.super_ = superCtor;
    ctor.prototype = Object.create(superCtor.prototype, {
      constructor: {
        value: ctor,
        enumerable: false,
        writable: true,
        configurable: true
      }
    });
  };
} else {
  inherits = function inherits(ctor, superCtor) {
    ctor.super_ = superCtor;
    var TempCtor = function () {};
    TempCtor.prototype = superCtor.prototype;
    ctor.prototype = new TempCtor();
    ctor.prototype.constructor = ctor;
  };
}
var inherits$1 = inherits;

var formatRegExp = /%[sdj%]/g;
function format(f) {
  if (!isString(f)) {
    var objects = [];
    for (var i = 0; i < arguments.length; i++) {
      objects.push(inspect(arguments[i]));
    }
    return objects.join(' ');
  }

  var i = 1;
  var args = arguments;
  var len = args.length;
  var str = String(f).replace(formatRegExp, function(x) {
    if (x === '%%') return '%';
    if (i >= len) return x;
    switch (x) {
      case '%s': return String(args[i++]);
      case '%d': return Number(args[i++]);
      case '%j':
        try {
          return JSON.stringify(args[i++]);
        } catch (_) {
          return '[Circular]';
        }
      default:
        return x;
    }
  });
  for (var x = args[i]; i < len; x = args[++i]) {
    if (isNull(x) || !isObject$1(x)) {
      str += ' ' + x;
    } else {
      str += ' ' + inspect(x);
    }
  }
  return str;
}

// Mark that a method should not be used.
// Returns a modified function which warns once by default.
// If --no-deprecation is set, then it is a no-op.
function deprecate(fn, msg) {
  // Allow for deprecating things in the process of starting up.
  if (isUndefined(global$1.process)) {
    return function() {
      return deprecate(fn, msg).apply(this, arguments);
    };
  }

  var warned = false;
  function deprecated() {
    if (!warned) {
      {
        console.error(msg);
      }
      warned = true;
    }
    return fn.apply(this, arguments);
  }

  return deprecated;
}

var debugs = {};
var debugEnviron;
function debuglog(set) {
  if (isUndefined(debugEnviron))
    debugEnviron = '';
  set = set.toUpperCase();
  if (!debugs[set]) {
    if (new RegExp('\\b' + set + '\\b', 'i').test(debugEnviron)) {
      var pid = 0;
      debugs[set] = function() {
        var msg = format.apply(null, arguments);
        console.error('%s %d: %s', set, pid, msg);
      };
    } else {
      debugs[set] = function() {};
    }
  }
  return debugs[set];
}

/**
 * Echos the value of a value. Trys to print the value out
 * in the best way possible given the different types.
 *
 * @param {Object} obj The object to print out.
 * @param {Object} opts Optional options object that alters the output.
 */
/* legacy: obj, showHidden, depth, colors*/
function inspect(obj, opts) {
  // default options
  var ctx = {
    seen: [],
    stylize: stylizeNoColor
  };
  // legacy...
  if (arguments.length >= 3) ctx.depth = arguments[2];
  if (arguments.length >= 4) ctx.colors = arguments[3];
  if (isBoolean(opts)) {
    // legacy...
    ctx.showHidden = opts;
  } else if (opts) {
    // got an "options" object
    _extend(ctx, opts);
  }
  // set default options
  if (isUndefined(ctx.showHidden)) ctx.showHidden = false;
  if (isUndefined(ctx.depth)) ctx.depth = 2;
  if (isUndefined(ctx.colors)) ctx.colors = false;
  if (isUndefined(ctx.customInspect)) ctx.customInspect = true;
  if (ctx.colors) ctx.stylize = stylizeWithColor;
  return formatValue(ctx, obj, ctx.depth);
}

// http://en.wikipedia.org/wiki/ANSI_escape_code#graphics
inspect.colors = {
  'bold' : [1, 22],
  'italic' : [3, 23],
  'underline' : [4, 24],
  'inverse' : [7, 27],
  'white' : [37, 39],
  'grey' : [90, 39],
  'black' : [30, 39],
  'blue' : [34, 39],
  'cyan' : [36, 39],
  'green' : [32, 39],
  'magenta' : [35, 39],
  'red' : [31, 39],
  'yellow' : [33, 39]
};

// Don't use 'blue' not visible on cmd.exe
inspect.styles = {
  'special': 'cyan',
  'number': 'yellow',
  'boolean': 'yellow',
  'undefined': 'grey',
  'null': 'bold',
  'string': 'green',
  'date': 'magenta',
  // "name": intentionally not styling
  'regexp': 'red'
};


function stylizeWithColor(str, styleType) {
  var style = inspect.styles[styleType];

  if (style) {
    return '\u001b[' + inspect.colors[style][0] + 'm' + str +
           '\u001b[' + inspect.colors[style][1] + 'm';
  } else {
    return str;
  }
}


function stylizeNoColor(str, styleType) {
  return str;
}


function arrayToHash(array) {
  var hash = {};

  array.forEach(function(val, idx) {
    hash[val] = true;
  });

  return hash;
}


function formatValue(ctx, value, recurseTimes) {
  // Provide a hook for user-specified inspect functions.
  // Check that value is an object with an inspect function on it
  if (ctx.customInspect &&
      value &&
      isFunction(value.inspect) &&
      // Filter out the util module, it's inspect function is special
      value.inspect !== inspect &&
      // Also filter out any prototype objects using the circular check.
      !(value.constructor && value.constructor.prototype === value)) {
    var ret = value.inspect(recurseTimes, ctx);
    if (!isString(ret)) {
      ret = formatValue(ctx, ret, recurseTimes);
    }
    return ret;
  }

  // Primitive types cannot have properties
  var primitive = formatPrimitive(ctx, value);
  if (primitive) {
    return primitive;
  }

  // Look up the keys of the object.
  var keys = Object.keys(value);
  var visibleKeys = arrayToHash(keys);

  if (ctx.showHidden) {
    keys = Object.getOwnPropertyNames(value);
  }

  // IE doesn't make error fields non-enumerable
  // http://msdn.microsoft.com/en-us/library/ie/dww52sbt(v=vs.94).aspx
  if (isError(value)
      && (keys.indexOf('message') >= 0 || keys.indexOf('description') >= 0)) {
    return formatError(value);
  }

  // Some type of object without properties can be shortcutted.
  if (keys.length === 0) {
    if (isFunction(value)) {
      var name = value.name ? ': ' + value.name : '';
      return ctx.stylize('[Function' + name + ']', 'special');
    }
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    }
    if (isDate(value)) {
      return ctx.stylize(Date.prototype.toString.call(value), 'date');
    }
    if (isError(value)) {
      return formatError(value);
    }
  }

  var base = '', array = false, braces = ['{', '}'];

  // Make Array say that they are Array
  if (isArray(value)) {
    array = true;
    braces = ['[', ']'];
  }

  // Make functions say that they are functions
  if (isFunction(value)) {
    var n = value.name ? ': ' + value.name : '';
    base = ' [Function' + n + ']';
  }

  // Make RegExps say that they are RegExps
  if (isRegExp(value)) {
    base = ' ' + RegExp.prototype.toString.call(value);
  }

  // Make dates with properties first say the date
  if (isDate(value)) {
    base = ' ' + Date.prototype.toUTCString.call(value);
  }

  // Make error with message first say the error
  if (isError(value)) {
    base = ' ' + formatError(value);
  }

  if (keys.length === 0 && (!array || value.length == 0)) {
    return braces[0] + base + braces[1];
  }

  if (recurseTimes < 0) {
    if (isRegExp(value)) {
      return ctx.stylize(RegExp.prototype.toString.call(value), 'regexp');
    } else {
      return ctx.stylize('[Object]', 'special');
    }
  }

  ctx.seen.push(value);

  var output;
  if (array) {
    output = formatArray(ctx, value, recurseTimes, visibleKeys, keys);
  } else {
    output = keys.map(function(key) {
      return formatProperty(ctx, value, recurseTimes, visibleKeys, key, array);
    });
  }

  ctx.seen.pop();

  return reduceToSingleString(output, base, braces);
}


function formatPrimitive(ctx, value) {
  if (isUndefined(value))
    return ctx.stylize('undefined', 'undefined');
  if (isString(value)) {
    var simple = '\'' + JSON.stringify(value).replace(/^"|"$/g, '')
                                             .replace(/'/g, "\\'")
                                             .replace(/\\"/g, '"') + '\'';
    return ctx.stylize(simple, 'string');
  }
  if (isNumber(value))
    return ctx.stylize('' + value, 'number');
  if (isBoolean(value))
    return ctx.stylize('' + value, 'boolean');
  // For some reason typeof null is "object", so special case here.
  if (isNull(value))
    return ctx.stylize('null', 'null');
}


function formatError(value) {
  return '[' + Error.prototype.toString.call(value) + ']';
}


function formatArray(ctx, value, recurseTimes, visibleKeys, keys) {
  var output = [];
  for (var i = 0, l = value.length; i < l; ++i) {
    if (hasOwnProperty(value, String(i))) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          String(i), true));
    } else {
      output.push('');
    }
  }
  keys.forEach(function(key) {
    if (!key.match(/^\d+$/)) {
      output.push(formatProperty(ctx, value, recurseTimes, visibleKeys,
          key, true));
    }
  });
  return output;
}


function formatProperty(ctx, value, recurseTimes, visibleKeys, key, array) {
  var name, str, desc;
  desc = Object.getOwnPropertyDescriptor(value, key) || { value: value[key] };
  if (desc.get) {
    if (desc.set) {
      str = ctx.stylize('[Getter/Setter]', 'special');
    } else {
      str = ctx.stylize('[Getter]', 'special');
    }
  } else {
    if (desc.set) {
      str = ctx.stylize('[Setter]', 'special');
    }
  }
  if (!hasOwnProperty(visibleKeys, key)) {
    name = '[' + key + ']';
  }
  if (!str) {
    if (ctx.seen.indexOf(desc.value) < 0) {
      if (isNull(recurseTimes)) {
        str = formatValue(ctx, desc.value, null);
      } else {
        str = formatValue(ctx, desc.value, recurseTimes - 1);
      }
      if (str.indexOf('\n') > -1) {
        if (array) {
          str = str.split('\n').map(function(line) {
            return '  ' + line;
          }).join('\n').substr(2);
        } else {
          str = '\n' + str.split('\n').map(function(line) {
            return '   ' + line;
          }).join('\n');
        }
      }
    } else {
      str = ctx.stylize('[Circular]', 'special');
    }
  }
  if (isUndefined(name)) {
    if (array && key.match(/^\d+$/)) {
      return str;
    }
    name = JSON.stringify('' + key);
    if (name.match(/^"([a-zA-Z_][a-zA-Z_0-9]*)"$/)) {
      name = name.substr(1, name.length - 2);
      name = ctx.stylize(name, 'name');
    } else {
      name = name.replace(/'/g, "\\'")
                 .replace(/\\"/g, '"')
                 .replace(/(^"|"$)/g, "'");
      name = ctx.stylize(name, 'string');
    }
  }

  return name + ': ' + str;
}


function reduceToSingleString(output, base, braces) {
  var length = output.reduce(function(prev, cur) {
    if (cur.indexOf('\n') >= 0) ;
    return prev + cur.replace(/\u001b\[\d\d?m/g, '').length + 1;
  }, 0);

  if (length > 60) {
    return braces[0] +
           (base === '' ? '' : base + '\n ') +
           ' ' +
           output.join(',\n  ') +
           ' ' +
           braces[1];
  }

  return braces[0] + base + ' ' + output.join(', ') + ' ' + braces[1];
}


// NOTE: These type checking functions intentionally don't use `instanceof`
// because it is fragile and can be easily faked with `Object.create()`.
function isArray(ar) {
  return Array.isArray(ar);
}

function isBoolean(arg) {
  return typeof arg === 'boolean';
}

function isNull(arg) {
  return arg === null;
}

function isNumber(arg) {
  return typeof arg === 'number';
}

function isString(arg) {
  return typeof arg === 'string';
}

function isUndefined(arg) {
  return arg === void 0;
}

function isRegExp(re) {
  return isObject$1(re) && objectToString(re) === '[object RegExp]';
}

function isObject$1(arg) {
  return typeof arg === 'object' && arg !== null;
}

function isDate(d) {
  return isObject$1(d) && objectToString(d) === '[object Date]';
}

function isError(e) {
  return isObject$1(e) &&
      (objectToString(e) === '[object Error]' || e instanceof Error);
}

function isFunction(arg) {
  return typeof arg === 'function';
}

function objectToString(o) {
  return Object.prototype.toString.call(o);
}

function _extend(origin, add) {
  // Don't do anything if add isn't an object
  if (!add || !isObject$1(add)) return origin;

  var keys = Object.keys(add);
  var i = keys.length;
  while (i--) {
    origin[keys[i]] = add[keys[i]];
  }
  return origin;
}
function hasOwnProperty(obj, prop) {
  return Object.prototype.hasOwnProperty.call(obj, prop);
}

function BufferList() {
  this.head = null;
  this.tail = null;
  this.length = 0;
}

BufferList.prototype.push = function (v) {
  var entry = { data: v, next: null };
  if (this.length > 0) this.tail.next = entry;else this.head = entry;
  this.tail = entry;
  ++this.length;
};

BufferList.prototype.unshift = function (v) {
  var entry = { data: v, next: this.head };
  if (this.length === 0) this.tail = entry;
  this.head = entry;
  ++this.length;
};

BufferList.prototype.shift = function () {
  if (this.length === 0) return;
  var ret = this.head.data;
  if (this.length === 1) this.head = this.tail = null;else this.head = this.head.next;
  --this.length;
  return ret;
};

BufferList.prototype.clear = function () {
  this.head = this.tail = null;
  this.length = 0;
};

BufferList.prototype.join = function (s) {
  if (this.length === 0) return '';
  var p = this.head;
  var ret = '' + p.data;
  while (p = p.next) {
    ret += s + p.data;
  }return ret;
};

BufferList.prototype.concat = function (n) {
  if (this.length === 0) return Buffer.alloc(0);
  if (this.length === 1) return this.head.data;
  var ret = Buffer.allocUnsafe(n >>> 0);
  var p = this.head;
  var i = 0;
  while (p) {
    p.data.copy(ret, i);
    i += p.data.length;
    p = p.next;
  }
  return ret;
};

// Copyright Joyent, Inc. and other Node contributors.
var isBufferEncoding = Buffer.isEncoding
  || function(encoding) {
       switch (encoding && encoding.toLowerCase()) {
         case 'hex': case 'utf8': case 'utf-8': case 'ascii': case 'binary': case 'base64': case 'ucs2': case 'ucs-2': case 'utf16le': case 'utf-16le': case 'raw': return true;
         default: return false;
       }
     };


function assertEncoding(encoding) {
  if (encoding && !isBufferEncoding(encoding)) {
    throw new Error('Unknown encoding: ' + encoding);
  }
}

// StringDecoder provides an interface for efficiently splitting a series of
// buffers into a series of JS strings without breaking apart multi-byte
// characters. CESU-8 is handled as part of the UTF-8 encoding.
//
// @TODO Handling all encodings inside a single object makes it very difficult
// to reason about this code, so it should be split up in the future.
// @TODO There should be a utf8-strict encoding that rejects invalid UTF-8 code
// points as used by CESU-8.
function StringDecoder(encoding) {
  this.encoding = (encoding || 'utf8').toLowerCase().replace(/[-_]/, '');
  assertEncoding(encoding);
  switch (this.encoding) {
    case 'utf8':
      // CESU-8 represents each of Surrogate Pair by 3-bytes
      this.surrogateSize = 3;
      break;
    case 'ucs2':
    case 'utf16le':
      // UTF-16 represents each of Surrogate Pair by 2-bytes
      this.surrogateSize = 2;
      this.detectIncompleteChar = utf16DetectIncompleteChar;
      break;
    case 'base64':
      // Base-64 stores 3 bytes in 4 chars, and pads the remainder.
      this.surrogateSize = 3;
      this.detectIncompleteChar = base64DetectIncompleteChar;
      break;
    default:
      this.write = passThroughWrite;
      return;
  }

  // Enough space to store all bytes of a single character. UTF-8 needs 4
  // bytes, but CESU-8 may require up to 6 (3 bytes per surrogate).
  this.charBuffer = new Buffer(6);
  // Number of bytes received for the current incomplete multi-byte character.
  this.charReceived = 0;
  // Number of bytes expected for the current incomplete multi-byte character.
  this.charLength = 0;
}

// write decodes the given buffer and returns it as JS string that is
// guaranteed to not contain any partial multi-byte characters. Any partial
// character found at the end of the buffer is buffered up, and will be
// returned when calling write again with the remaining bytes.
//
// Note: Converting a Buffer containing an orphan surrogate to a String
// currently works, but converting a String to a Buffer (via `new Buffer`, or
// Buffer#write) will replace incomplete surrogates with the unicode
// replacement character. See https://codereview.chromium.org/121173009/ .
StringDecoder.prototype.write = function(buffer) {
  var charStr = '';
  // if our last write ended with an incomplete multibyte character
  while (this.charLength) {
    // determine how many remaining bytes this buffer has to offer for this char
    var available = (buffer.length >= this.charLength - this.charReceived) ?
        this.charLength - this.charReceived :
        buffer.length;

    // add the new bytes to the char buffer
    buffer.copy(this.charBuffer, this.charReceived, 0, available);
    this.charReceived += available;

    if (this.charReceived < this.charLength) {
      // still not enough chars in this buffer? wait for more ...
      return '';
    }

    // remove bytes belonging to the current character from the buffer
    buffer = buffer.slice(available, buffer.length);

    // get the character that was split
    charStr = this.charBuffer.slice(0, this.charLength).toString(this.encoding);

    // CESU-8: lead surrogate (D800-DBFF) is also the incomplete character
    var charCode = charStr.charCodeAt(charStr.length - 1);
    if (charCode >= 0xD800 && charCode <= 0xDBFF) {
      this.charLength += this.surrogateSize;
      charStr = '';
      continue;
    }
    this.charReceived = this.charLength = 0;

    // if there are no more bytes in this buffer, just emit our char
    if (buffer.length === 0) {
      return charStr;
    }
    break;
  }

  // determine and set charLength / charReceived
  this.detectIncompleteChar(buffer);

  var end = buffer.length;
  if (this.charLength) {
    // buffer the incomplete character bytes we got
    buffer.copy(this.charBuffer, 0, buffer.length - this.charReceived, end);
    end -= this.charReceived;
  }

  charStr += buffer.toString(this.encoding, 0, end);

  var end = charStr.length - 1;
  var charCode = charStr.charCodeAt(end);
  // CESU-8: lead surrogate (D800-DBFF) is also the incomplete character
  if (charCode >= 0xD800 && charCode <= 0xDBFF) {
    var size = this.surrogateSize;
    this.charLength += size;
    this.charReceived += size;
    this.charBuffer.copy(this.charBuffer, size, 0, size);
    buffer.copy(this.charBuffer, 0, 0, size);
    return charStr.substring(0, end);
  }

  // or just emit the charStr
  return charStr;
};

// detectIncompleteChar determines if there is an incomplete UTF-8 character at
// the end of the given buffer. If so, it sets this.charLength to the byte
// length that character, and sets this.charReceived to the number of bytes
// that are available for this character.
StringDecoder.prototype.detectIncompleteChar = function(buffer) {
  // determine how many bytes we have to check at the end of this buffer
  var i = (buffer.length >= 3) ? 3 : buffer.length;

  // Figure out if one of the last i bytes of our buffer announces an
  // incomplete char.
  for (; i > 0; i--) {
    var c = buffer[buffer.length - i];

    // See http://en.wikipedia.org/wiki/UTF-8#Description

    // 110XXXXX
    if (i == 1 && c >> 5 == 0x06) {
      this.charLength = 2;
      break;
    }

    // 1110XXXX
    if (i <= 2 && c >> 4 == 0x0E) {
      this.charLength = 3;
      break;
    }

    // 11110XXX
    if (i <= 3 && c >> 3 == 0x1E) {
      this.charLength = 4;
      break;
    }
  }
  this.charReceived = i;
};

StringDecoder.prototype.end = function(buffer) {
  var res = '';
  if (buffer && buffer.length)
    res = this.write(buffer);

  if (this.charReceived) {
    var cr = this.charReceived;
    var buf = this.charBuffer;
    var enc = this.encoding;
    res += buf.slice(0, cr).toString(enc);
  }

  return res;
};

function passThroughWrite(buffer) {
  return buffer.toString(this.encoding);
}

function utf16DetectIncompleteChar(buffer) {
  this.charReceived = buffer.length % 2;
  this.charLength = this.charReceived ? 2 : 0;
}

function base64DetectIncompleteChar(buffer) {
  this.charReceived = buffer.length % 3;
  this.charLength = this.charReceived ? 3 : 0;
}

Readable.ReadableState = ReadableState;

var debug = debuglog('stream');
inherits$1(Readable, EventEmitter);

function prependListener(emitter, event, fn) {
  // Sadly this is not cacheable as some libraries bundle their own
  // event emitter implementation with them.
  if (typeof emitter.prependListener === 'function') {
    return emitter.prependListener(event, fn);
  } else {
    // This is a hack to make sure that our error handler is attached before any
    // userland ones.  NEVER DO THIS. This is here only because this code needs
    // to continue to work with older versions of Node.js that do not include
    // the prependListener() method. The goal is to eventually remove this hack.
    if (!emitter._events || !emitter._events[event])
      emitter.on(event, fn);
    else if (Array.isArray(emitter._events[event]))
      emitter._events[event].unshift(fn);
    else
      emitter._events[event] = [fn, emitter._events[event]];
  }
}
function listenerCount (emitter, type) {
  return emitter.listeners(type).length;
}
function ReadableState(options, stream) {

  options = options || {};

  // object stream flag. Used to make read(n) ignore n and to
  // make all the buffer merging and length checks go away
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex) this.objectMode = this.objectMode || !!options.readableObjectMode;

  // the point at which it stops calling _read() to fill the buffer
  // Note: 0 is a valid value, means "don't call _read preemptively ever"
  var hwm = options.highWaterMark;
  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = hwm || hwm === 0 ? hwm : defaultHwm;

  // cast to ints.
  this.highWaterMark = ~ ~this.highWaterMark;

  // A linked list is used to store data chunks instead of an array because the
  // linked list can remove elements from the beginning faster than
  // array.shift()
  this.buffer = new BufferList();
  this.length = 0;
  this.pipes = null;
  this.pipesCount = 0;
  this.flowing = null;
  this.ended = false;
  this.endEmitted = false;
  this.reading = false;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // whenever we return null, then we set a flag to say
  // that we're awaiting a 'readable' event emission.
  this.needReadable = false;
  this.emittedReadable = false;
  this.readableListening = false;
  this.resumeScheduled = false;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // when piping, we only care about 'readable' events that happen
  // after read()ing all the bytes and not getting any pushback.
  this.ranOut = false;

  // the number of writers that are awaiting a drain event in .pipe()s
  this.awaitDrain = 0;

  // if true, a maybeReadMore has been scheduled
  this.readingMore = false;

  this.decoder = null;
  this.encoding = null;
  if (options.encoding) {
    this.decoder = new StringDecoder(options.encoding);
    this.encoding = options.encoding;
  }
}
function Readable(options) {

  if (!(this instanceof Readable)) return new Readable(options);

  this._readableState = new ReadableState(options, this);

  // legacy
  this.readable = true;

  if (options && typeof options.read === 'function') this._read = options.read;

  EventEmitter.call(this);
}

// Manually shove something into the read() buffer.
// This returns true if the highWaterMark has not been hit yet,
// similar to how Writable.write() returns true if you should
// write() some more.
Readable.prototype.push = function (chunk, encoding) {
  var state = this._readableState;

  if (!state.objectMode && typeof chunk === 'string') {
    encoding = encoding || state.defaultEncoding;
    if (encoding !== state.encoding) {
      chunk = Buffer.from(chunk, encoding);
      encoding = '';
    }
  }

  return readableAddChunk(this, state, chunk, encoding, false);
};

// Unshift should *always* be something directly out of read()
Readable.prototype.unshift = function (chunk) {
  var state = this._readableState;
  return readableAddChunk(this, state, chunk, '', true);
};

Readable.prototype.isPaused = function () {
  return this._readableState.flowing === false;
};

function readableAddChunk(stream, state, chunk, encoding, addToFront) {
  var er = chunkInvalid(state, chunk);
  if (er) {
    stream.emit('error', er);
  } else if (chunk === null) {
    state.reading = false;
    onEofChunk(stream, state);
  } else if (state.objectMode || chunk && chunk.length > 0) {
    if (state.ended && !addToFront) {
      var e = new Error('stream.push() after EOF');
      stream.emit('error', e);
    } else if (state.endEmitted && addToFront) {
      var _e = new Error('stream.unshift() after end event');
      stream.emit('error', _e);
    } else {
      var skipAdd;
      if (state.decoder && !addToFront && !encoding) {
        chunk = state.decoder.write(chunk);
        skipAdd = !state.objectMode && chunk.length === 0;
      }

      if (!addToFront) state.reading = false;

      // Don't add to the buffer if we've decoded to an empty string chunk and
      // we're not in object mode
      if (!skipAdd) {
        // if we want the data now, just emit it.
        if (state.flowing && state.length === 0 && !state.sync) {
          stream.emit('data', chunk);
          stream.read(0);
        } else {
          // update the buffer info.
          state.length += state.objectMode ? 1 : chunk.length;
          if (addToFront) state.buffer.unshift(chunk);else state.buffer.push(chunk);

          if (state.needReadable) emitReadable(stream);
        }
      }

      maybeReadMore(stream, state);
    }
  } else if (!addToFront) {
    state.reading = false;
  }

  return needMoreData(state);
}

// if it's past the high water mark, we can push in some more.
// Also, if we have no data yet, we can stand some
// more bytes.  This is to work around cases where hwm=0,
// such as the repl.  Also, if the push() triggered a
// readable event, and the user called read(largeNumber) such that
// needReadable was set, then we ought to push more, so that another
// 'readable' event will be triggered.
function needMoreData(state) {
  return !state.ended && (state.needReadable || state.length < state.highWaterMark || state.length === 0);
}

// backwards compatibility.
Readable.prototype.setEncoding = function (enc) {
  this._readableState.decoder = new StringDecoder(enc);
  this._readableState.encoding = enc;
  return this;
};

// Don't raise the hwm > 8MB
var MAX_HWM = 0x800000;
function computeNewHighWaterMark(n) {
  if (n >= MAX_HWM) {
    n = MAX_HWM;
  } else {
    // Get the next highest power of 2 to prevent increasing hwm excessively in
    // tiny amounts
    n--;
    n |= n >>> 1;
    n |= n >>> 2;
    n |= n >>> 4;
    n |= n >>> 8;
    n |= n >>> 16;
    n++;
  }
  return n;
}

// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function howMuchToRead(n, state) {
  if (n <= 0 || state.length === 0 && state.ended) return 0;
  if (state.objectMode) return 1;
  if (n !== n) {
    // Only flow one buffer at a time
    if (state.flowing && state.length) return state.buffer.head.data.length;else return state.length;
  }
  // If we're asking for more than the current hwm, then raise the hwm.
  if (n > state.highWaterMark) state.highWaterMark = computeNewHighWaterMark(n);
  if (n <= state.length) return n;
  // Don't have enough
  if (!state.ended) {
    state.needReadable = true;
    return 0;
  }
  return state.length;
}

// you can override either this method, or the async _read(n) below.
Readable.prototype.read = function (n) {
  debug('read', n);
  n = parseInt(n, 10);
  var state = this._readableState;
  var nOrig = n;

  if (n !== 0) state.emittedReadable = false;

  // if we're doing read(0) to trigger a readable event, but we
  // already have a bunch of data in the buffer, then just trigger
  // the 'readable' event and move on.
  if (n === 0 && state.needReadable && (state.length >= state.highWaterMark || state.ended)) {
    debug('read: emitReadable', state.length, state.ended);
    if (state.length === 0 && state.ended) endReadable(this);else emitReadable(this);
    return null;
  }

  n = howMuchToRead(n, state);

  // if we've ended, and we're now clear, then finish it up.
  if (n === 0 && state.ended) {
    if (state.length === 0) endReadable(this);
    return null;
  }

  // All the actual chunk generation logic needs to be
  // *below* the call to _read.  The reason is that in certain
  // synthetic stream cases, such as passthrough streams, _read
  // may be a completely synchronous operation which may change
  // the state of the read buffer, providing enough data when
  // before there was *not* enough.
  //
  // So, the steps are:
  // 1. Figure out what the state of things will be after we do
  // a read from the buffer.
  //
  // 2. If that resulting state will trigger a _read, then call _read.
  // Note that this may be asynchronous, or synchronous.  Yes, it is
  // deeply ugly to write APIs this way, but that still doesn't mean
  // that the Readable class should behave improperly, as streams are
  // designed to be sync/async agnostic.
  // Take note if the _read call is sync or async (ie, if the read call
  // has returned yet), so that we know whether or not it's safe to emit
  // 'readable' etc.
  //
  // 3. Actually pull the requested chunks out of the buffer and return.

  // if we need a readable event, then we need to do some reading.
  var doRead = state.needReadable;
  debug('need readable', doRead);

  // if we currently have less than the highWaterMark, then also read some
  if (state.length === 0 || state.length - n < state.highWaterMark) {
    doRead = true;
    debug('length less than watermark', doRead);
  }

  // however, if we've ended, then there's no point, and if we're already
  // reading, then it's unnecessary.
  if (state.ended || state.reading) {
    doRead = false;
    debug('reading or ended', doRead);
  } else if (doRead) {
    debug('do read');
    state.reading = true;
    state.sync = true;
    // if the length is currently zero, then we *need* a readable event.
    if (state.length === 0) state.needReadable = true;
    // call internal read method
    this._read(state.highWaterMark);
    state.sync = false;
    // If _read pushed data synchronously, then `reading` will be false,
    // and we need to re-evaluate how much data we can return to the user.
    if (!state.reading) n = howMuchToRead(nOrig, state);
  }

  var ret;
  if (n > 0) ret = fromList(n, state);else ret = null;

  if (ret === null) {
    state.needReadable = true;
    n = 0;
  } else {
    state.length -= n;
  }

  if (state.length === 0) {
    // If we have nothing in the buffer, then we want to know
    // as soon as we *do* get something into the buffer.
    if (!state.ended) state.needReadable = true;

    // If we tried to read() past the EOF, then emit end on the next tick.
    if (nOrig !== n && state.ended) endReadable(this);
  }

  if (ret !== null) this.emit('data', ret);

  return ret;
};

function chunkInvalid(state, chunk) {
  var er = null;
  if (!isBuffer(chunk) && typeof chunk !== 'string' && chunk !== null && chunk !== undefined && !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  return er;
}

function onEofChunk(stream, state) {
  if (state.ended) return;
  if (state.decoder) {
    var chunk = state.decoder.end();
    if (chunk && chunk.length) {
      state.buffer.push(chunk);
      state.length += state.objectMode ? 1 : chunk.length;
    }
  }
  state.ended = true;

  // emit 'readable' now to make sure it gets picked up.
  emitReadable(stream);
}

// Don't emit readable right away in sync mode, because this can trigger
// another read() call => stack overflow.  This way, it might trigger
// a nextTick recursion warning, but that's not so bad.
function emitReadable(stream) {
  var state = stream._readableState;
  state.needReadable = false;
  if (!state.emittedReadable) {
    debug('emitReadable', state.flowing);
    state.emittedReadable = true;
    if (state.sync) nextTick(emitReadable_, stream);else emitReadable_(stream);
  }
}

function emitReadable_(stream) {
  debug('emit readable');
  stream.emit('readable');
  flow(stream);
}

// at this point, the user has presumably seen the 'readable' event,
// and called read() to consume some data.  that may have triggered
// in turn another _read(n) call, in which case reading = true if
// it's in progress.
// However, if we're not ended, or reading, and the length < hwm,
// then go ahead and try to read some more preemptively.
function maybeReadMore(stream, state) {
  if (!state.readingMore) {
    state.readingMore = true;
    nextTick(maybeReadMore_, stream, state);
  }
}

function maybeReadMore_(stream, state) {
  var len = state.length;
  while (!state.reading && !state.flowing && !state.ended && state.length < state.highWaterMark) {
    debug('maybeReadMore read 0');
    stream.read(0);
    if (len === state.length)
      // didn't get any data, stop spinning.
      break;else len = state.length;
  }
  state.readingMore = false;
}

// abstract method.  to be overridden in specific implementation classes.
// call cb(er, data) where data is <= n in length.
// for virtual (non-string, non-buffer) streams, "length" is somewhat
// arbitrary, and perhaps not very meaningful.
Readable.prototype._read = function (n) {
  this.emit('error', new Error('not implemented'));
};

Readable.prototype.pipe = function (dest, pipeOpts) {
  var src = this;
  var state = this._readableState;

  switch (state.pipesCount) {
    case 0:
      state.pipes = dest;
      break;
    case 1:
      state.pipes = [state.pipes, dest];
      break;
    default:
      state.pipes.push(dest);
      break;
  }
  state.pipesCount += 1;
  debug('pipe count=%d opts=%j', state.pipesCount, pipeOpts);

  var doEnd = (!pipeOpts || pipeOpts.end !== false);

  var endFn = doEnd ? onend : cleanup;
  if (state.endEmitted) nextTick(endFn);else src.once('end', endFn);

  dest.on('unpipe', onunpipe);
  function onunpipe(readable) {
    debug('onunpipe');
    if (readable === src) {
      cleanup();
    }
  }

  function onend() {
    debug('onend');
    dest.end();
  }

  // when the dest drains, it reduces the awaitDrain counter
  // on the source.  This would be more elegant with a .once()
  // handler in flow(), but adding and removing repeatedly is
  // too slow.
  var ondrain = pipeOnDrain(src);
  dest.on('drain', ondrain);

  var cleanedUp = false;
  function cleanup() {
    debug('cleanup');
    // cleanup event handlers once the pipe is broken
    dest.removeListener('close', onclose);
    dest.removeListener('finish', onfinish);
    dest.removeListener('drain', ondrain);
    dest.removeListener('error', onerror);
    dest.removeListener('unpipe', onunpipe);
    src.removeListener('end', onend);
    src.removeListener('end', cleanup);
    src.removeListener('data', ondata);

    cleanedUp = true;

    // if the reader is waiting for a drain event from this
    // specific writer, then it would cause it to never start
    // flowing again.
    // So, if this is awaiting a drain, then we just call it now.
    // If we don't know, then assume that we are waiting for one.
    if (state.awaitDrain && (!dest._writableState || dest._writableState.needDrain)) ondrain();
  }

  // If the user pushes more data while we're writing to dest then we'll end up
  // in ondata again. However, we only want to increase awaitDrain once because
  // dest will only emit one 'drain' event for the multiple writes.
  // => Introduce a guard on increasing awaitDrain.
  var increasedAwaitDrain = false;
  src.on('data', ondata);
  function ondata(chunk) {
    debug('ondata');
    increasedAwaitDrain = false;
    var ret = dest.write(chunk);
    if (false === ret && !increasedAwaitDrain) {
      // If the user unpiped during `dest.write()`, it is possible
      // to get stuck in a permanently paused state if that write
      // also returned false.
      // => Check whether `dest` is still a piping destination.
      if ((state.pipesCount === 1 && state.pipes === dest || state.pipesCount > 1 && indexOf(state.pipes, dest) !== -1) && !cleanedUp) {
        debug('false write response, pause', src._readableState.awaitDrain);
        src._readableState.awaitDrain++;
        increasedAwaitDrain = true;
      }
      src.pause();
    }
  }

  // if the dest has an error, then stop piping into it.
  // however, don't suppress the throwing behavior for this.
  function onerror(er) {
    debug('onerror', er);
    unpipe();
    dest.removeListener('error', onerror);
    if (listenerCount(dest, 'error') === 0) dest.emit('error', er);
  }

  // Make sure our error handler is attached before userland ones.
  prependListener(dest, 'error', onerror);

  // Both close and finish should trigger unpipe, but only once.
  function onclose() {
    dest.removeListener('finish', onfinish);
    unpipe();
  }
  dest.once('close', onclose);
  function onfinish() {
    debug('onfinish');
    dest.removeListener('close', onclose);
    unpipe();
  }
  dest.once('finish', onfinish);

  function unpipe() {
    debug('unpipe');
    src.unpipe(dest);
  }

  // tell the dest that it's being piped to
  dest.emit('pipe', src);

  // start the flow if it hasn't been started already.
  if (!state.flowing) {
    debug('pipe resume');
    src.resume();
  }

  return dest;
};

function pipeOnDrain(src) {
  return function () {
    var state = src._readableState;
    debug('pipeOnDrain', state.awaitDrain);
    if (state.awaitDrain) state.awaitDrain--;
    if (state.awaitDrain === 0 && src.listeners('data').length) {
      state.flowing = true;
      flow(src);
    }
  };
}

Readable.prototype.unpipe = function (dest) {
  var state = this._readableState;

  // if we're not piping anywhere, then do nothing.
  if (state.pipesCount === 0) return this;

  // just one destination.  most common case.
  if (state.pipesCount === 1) {
    // passed in one, but it's not the right one.
    if (dest && dest !== state.pipes) return this;

    if (!dest) dest = state.pipes;

    // got a match.
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;
    if (dest) dest.emit('unpipe', this);
    return this;
  }

  // slow case. multiple pipe destinations.

  if (!dest) {
    // remove all.
    var dests = state.pipes;
    var len = state.pipesCount;
    state.pipes = null;
    state.pipesCount = 0;
    state.flowing = false;

    for (var _i = 0; _i < len; _i++) {
      dests[_i].emit('unpipe', this);
    }return this;
  }

  // try to find the right one.
  var i = indexOf(state.pipes, dest);
  if (i === -1) return this;

  state.pipes.splice(i, 1);
  state.pipesCount -= 1;
  if (state.pipesCount === 1) state.pipes = state.pipes[0];

  dest.emit('unpipe', this);

  return this;
};

// set up data events if they are asked for
// Ensure readable listeners eventually get something
Readable.prototype.on = function (ev, fn) {
  var res = EventEmitter.prototype.on.call(this, ev, fn);

  if (ev === 'data') {
    // Start flowing on next tick if stream isn't explicitly paused
    if (this._readableState.flowing !== false) this.resume();
  } else if (ev === 'readable') {
    var state = this._readableState;
    if (!state.endEmitted && !state.readableListening) {
      state.readableListening = state.needReadable = true;
      state.emittedReadable = false;
      if (!state.reading) {
        nextTick(nReadingNextTick, this);
      } else if (state.length) {
        emitReadable(this);
      }
    }
  }

  return res;
};
Readable.prototype.addListener = Readable.prototype.on;

function nReadingNextTick(self) {
  debug('readable nexttick read 0');
  self.read(0);
}

// pause() and resume() are remnants of the legacy readable stream API
// If the user uses them, then switch into old mode.
Readable.prototype.resume = function () {
  var state = this._readableState;
  if (!state.flowing) {
    debug('resume');
    state.flowing = true;
    resume(this, state);
  }
  return this;
};

function resume(stream, state) {
  if (!state.resumeScheduled) {
    state.resumeScheduled = true;
    nextTick(resume_, stream, state);
  }
}

function resume_(stream, state) {
  if (!state.reading) {
    debug('resume read 0');
    stream.read(0);
  }

  state.resumeScheduled = false;
  state.awaitDrain = 0;
  stream.emit('resume');
  flow(stream);
  if (state.flowing && !state.reading) stream.read(0);
}

Readable.prototype.pause = function () {
  debug('call pause flowing=%j', this._readableState.flowing);
  if (false !== this._readableState.flowing) {
    debug('pause');
    this._readableState.flowing = false;
    this.emit('pause');
  }
  return this;
};

function flow(stream) {
  var state = stream._readableState;
  debug('flow', state.flowing);
  while (state.flowing && stream.read() !== null) {}
}

// wrap an old-style stream as the async data source.
// This is *not* part of the readable stream interface.
// It is an ugly unfortunate mess of history.
Readable.prototype.wrap = function (stream) {
  var state = this._readableState;
  var paused = false;

  var self = this;
  stream.on('end', function () {
    debug('wrapped end');
    if (state.decoder && !state.ended) {
      var chunk = state.decoder.end();
      if (chunk && chunk.length) self.push(chunk);
    }

    self.push(null);
  });

  stream.on('data', function (chunk) {
    debug('wrapped data');
    if (state.decoder) chunk = state.decoder.write(chunk);

    // don't skip over falsy values in objectMode
    if (state.objectMode && (chunk === null || chunk === undefined)) return;else if (!state.objectMode && (!chunk || !chunk.length)) return;

    var ret = self.push(chunk);
    if (!ret) {
      paused = true;
      stream.pause();
    }
  });

  // proxy all the other methods.
  // important when wrapping filters and duplexes.
  for (var i in stream) {
    if (this[i] === undefined && typeof stream[i] === 'function') {
      this[i] = function (method) {
        return function () {
          return stream[method].apply(stream, arguments);
        };
      }(i);
    }
  }

  // proxy certain important events.
  var events = ['error', 'close', 'destroy', 'pause', 'resume'];
  forEach(events, function (ev) {
    stream.on(ev, self.emit.bind(self, ev));
  });

  // when we try to consume some more bytes, simply unpause the
  // underlying stream.
  self._read = function (n) {
    debug('wrapped _read', n);
    if (paused) {
      paused = false;
      stream.resume();
    }
  };

  return self;
};

// exposed for testing purposes only.
Readable._fromList = fromList;

// Pluck off n bytes from an array of buffers.
// Length is the combined lengths of all the buffers in the list.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function fromList(n, state) {
  // nothing buffered
  if (state.length === 0) return null;

  var ret;
  if (state.objectMode) ret = state.buffer.shift();else if (!n || n >= state.length) {
    // read it all, truncate the list
    if (state.decoder) ret = state.buffer.join('');else if (state.buffer.length === 1) ret = state.buffer.head.data;else ret = state.buffer.concat(state.length);
    state.buffer.clear();
  } else {
    // read part of list
    ret = fromListPartial(n, state.buffer, state.decoder);
  }

  return ret;
}

// Extracts only enough buffered data to satisfy the amount requested.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function fromListPartial(n, list, hasStrings) {
  var ret;
  if (n < list.head.data.length) {
    // slice is the same for buffers and strings
    ret = list.head.data.slice(0, n);
    list.head.data = list.head.data.slice(n);
  } else if (n === list.head.data.length) {
    // first chunk is a perfect match
    ret = list.shift();
  } else {
    // result spans more than one buffer
    ret = hasStrings ? copyFromBufferString(n, list) : copyFromBuffer(n, list);
  }
  return ret;
}

// Copies a specified amount of characters from the list of buffered data
// chunks.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function copyFromBufferString(n, list) {
  var p = list.head;
  var c = 1;
  var ret = p.data;
  n -= ret.length;
  while (p = p.next) {
    var str = p.data;
    var nb = n > str.length ? str.length : n;
    if (nb === str.length) ret += str;else ret += str.slice(0, n);
    n -= nb;
    if (n === 0) {
      if (nb === str.length) {
        ++c;
        if (p.next) list.head = p.next;else list.head = list.tail = null;
      } else {
        list.head = p;
        p.data = str.slice(nb);
      }
      break;
    }
    ++c;
  }
  list.length -= c;
  return ret;
}

// Copies a specified amount of bytes from the list of buffered data chunks.
// This function is designed to be inlinable, so please take care when making
// changes to the function body.
function copyFromBuffer(n, list) {
  var ret = Buffer.allocUnsafe(n);
  var p = list.head;
  var c = 1;
  p.data.copy(ret);
  n -= p.data.length;
  while (p = p.next) {
    var buf = p.data;
    var nb = n > buf.length ? buf.length : n;
    buf.copy(ret, ret.length - n, 0, nb);
    n -= nb;
    if (n === 0) {
      if (nb === buf.length) {
        ++c;
        if (p.next) list.head = p.next;else list.head = list.tail = null;
      } else {
        list.head = p;
        p.data = buf.slice(nb);
      }
      break;
    }
    ++c;
  }
  list.length -= c;
  return ret;
}

function endReadable(stream) {
  var state = stream._readableState;

  // If we get here before consuming all the bytes, then that is a
  // bug in node.  Should never happen.
  if (state.length > 0) throw new Error('"endReadable()" called on non-empty stream');

  if (!state.endEmitted) {
    state.ended = true;
    nextTick(endReadableNT, state, stream);
  }
}

function endReadableNT(state, stream) {
  // Check that we didn't get one last unshift.
  if (!state.endEmitted && state.length === 0) {
    state.endEmitted = true;
    stream.readable = false;
    stream.emit('end');
  }
}

function forEach(xs, f) {
  for (var i = 0, l = xs.length; i < l; i++) {
    f(xs[i], i);
  }
}

function indexOf(xs, x) {
  for (var i = 0, l = xs.length; i < l; i++) {
    if (xs[i] === x) return i;
  }
  return -1;
}

// A bit simpler than readable streams.
Writable.WritableState = WritableState;
inherits$1(Writable, EventEmitter);

function nop() {}

function WriteReq(chunk, encoding, cb) {
  this.chunk = chunk;
  this.encoding = encoding;
  this.callback = cb;
  this.next = null;
}

function WritableState(options, stream) {
  Object.defineProperty(this, 'buffer', {
    get: deprecate(function () {
      return this.getBuffer();
    }, '_writableState.buffer is deprecated. Use _writableState.getBuffer ' + 'instead.')
  });
  options = options || {};

  // object stream flag to indicate whether or not this stream
  // contains buffers or objects.
  this.objectMode = !!options.objectMode;

  if (stream instanceof Duplex) this.objectMode = this.objectMode || !!options.writableObjectMode;

  // the point at which write() starts returning false
  // Note: 0 is a valid value, means that we always return false if
  // the entire buffer is not flushed immediately on write()
  var hwm = options.highWaterMark;
  var defaultHwm = this.objectMode ? 16 : 16 * 1024;
  this.highWaterMark = hwm || hwm === 0 ? hwm : defaultHwm;

  // cast to ints.
  this.highWaterMark = ~ ~this.highWaterMark;

  this.needDrain = false;
  // at the start of calling end()
  this.ending = false;
  // when end() has been called, and returned
  this.ended = false;
  // when 'finish' is emitted
  this.finished = false;

  // should we decode strings into buffers before passing to _write?
  // this is here so that some node-core streams can optimize string
  // handling at a lower level.
  var noDecode = options.decodeStrings === false;
  this.decodeStrings = !noDecode;

  // Crypto is kind of old and crusty.  Historically, its default string
  // encoding is 'binary' so we have to make this configurable.
  // Everything else in the universe uses 'utf8', though.
  this.defaultEncoding = options.defaultEncoding || 'utf8';

  // not an actual buffer we keep track of, but a measurement
  // of how much we're waiting to get pushed to some underlying
  // socket or file.
  this.length = 0;

  // a flag to see when we're in the middle of a write.
  this.writing = false;

  // when true all writes will be buffered until .uncork() call
  this.corked = 0;

  // a flag to be able to tell if the onwrite cb is called immediately,
  // or on a later tick.  We set this to true at first, because any
  // actions that shouldn't happen until "later" should generally also
  // not happen before the first write call.
  this.sync = true;

  // a flag to know if we're processing previously buffered items, which
  // may call the _write() callback in the same tick, so that we don't
  // end up in an overlapped onwrite situation.
  this.bufferProcessing = false;

  // the callback that's passed to _write(chunk,cb)
  this.onwrite = function (er) {
    onwrite(stream, er);
  };

  // the callback that the user supplies to write(chunk,encoding,cb)
  this.writecb = null;

  // the amount that is being written when _write is called.
  this.writelen = 0;

  this.bufferedRequest = null;
  this.lastBufferedRequest = null;

  // number of pending user-supplied write callbacks
  // this must be 0 before 'finish' can be emitted
  this.pendingcb = 0;

  // emit prefinish if the only thing we're waiting for is _write cbs
  // This is relevant for synchronous Transform streams
  this.prefinished = false;

  // True if the error was already emitted and should not be thrown again
  this.errorEmitted = false;

  // count buffered requests
  this.bufferedRequestCount = 0;

  // allocate the first CorkedRequest, there is always
  // one allocated and free to use, and we maintain at most two
  this.corkedRequestsFree = new CorkedRequest(this);
}

WritableState.prototype.getBuffer = function writableStateGetBuffer() {
  var current = this.bufferedRequest;
  var out = [];
  while (current) {
    out.push(current);
    current = current.next;
  }
  return out;
};
function Writable(options) {

  // Writable ctor is applied to Duplexes, though they're not
  // instanceof Writable, they're instanceof Readable.
  if (!(this instanceof Writable) && !(this instanceof Duplex)) return new Writable(options);

  this._writableState = new WritableState(options, this);

  // legacy.
  this.writable = true;

  if (options) {
    if (typeof options.write === 'function') this._write = options.write;

    if (typeof options.writev === 'function') this._writev = options.writev;
  }

  EventEmitter.call(this);
}

// Otherwise people can pipe Writable streams, which is just wrong.
Writable.prototype.pipe = function () {
  this.emit('error', new Error('Cannot pipe, not readable'));
};

function writeAfterEnd(stream, cb) {
  var er = new Error('write after end');
  // TODO: defer error events consistently everywhere, not just the cb
  stream.emit('error', er);
  nextTick(cb, er);
}

// If we get something that is not a buffer, string, null, or undefined,
// and we're not in objectMode, then that's an error.
// Otherwise stream chunks are all considered to be of length=1, and the
// watermarks determine how many objects to keep in the buffer, rather than
// how many bytes or characters.
function validChunk(stream, state, chunk, cb) {
  var valid = true;
  var er = false;
  // Always throw error if a null is written
  // if we are not in object mode then throw
  // if it is not a buffer, string, or undefined.
  if (chunk === null) {
    er = new TypeError('May not write null values to stream');
  } else if (!Buffer.isBuffer(chunk) && typeof chunk !== 'string' && chunk !== undefined && !state.objectMode) {
    er = new TypeError('Invalid non-string/buffer chunk');
  }
  if (er) {
    stream.emit('error', er);
    nextTick(cb, er);
    valid = false;
  }
  return valid;
}

Writable.prototype.write = function (chunk, encoding, cb) {
  var state = this._writableState;
  var ret = false;

  if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (Buffer.isBuffer(chunk)) encoding = 'buffer';else if (!encoding) encoding = state.defaultEncoding;

  if (typeof cb !== 'function') cb = nop;

  if (state.ended) writeAfterEnd(this, cb);else if (validChunk(this, state, chunk, cb)) {
    state.pendingcb++;
    ret = writeOrBuffer(this, state, chunk, encoding, cb);
  }

  return ret;
};

Writable.prototype.cork = function () {
  var state = this._writableState;

  state.corked++;
};

Writable.prototype.uncork = function () {
  var state = this._writableState;

  if (state.corked) {
    state.corked--;

    if (!state.writing && !state.corked && !state.finished && !state.bufferProcessing && state.bufferedRequest) clearBuffer(this, state);
  }
};

Writable.prototype.setDefaultEncoding = function setDefaultEncoding(encoding) {
  // node::ParseEncoding() requires lower case.
  if (typeof encoding === 'string') encoding = encoding.toLowerCase();
  if (!(['hex', 'utf8', 'utf-8', 'ascii', 'binary', 'base64', 'ucs2', 'ucs-2', 'utf16le', 'utf-16le', 'raw'].indexOf((encoding + '').toLowerCase()) > -1)) throw new TypeError('Unknown encoding: ' + encoding);
  this._writableState.defaultEncoding = encoding;
  return this;
};

function decodeChunk(state, chunk, encoding) {
  if (!state.objectMode && state.decodeStrings !== false && typeof chunk === 'string') {
    chunk = Buffer.from(chunk, encoding);
  }
  return chunk;
}

// if we're already writing something, then just put this
// in the queue, and wait our turn.  Otherwise, call _write
// If we return false, then we need a drain event, so set that flag.
function writeOrBuffer(stream, state, chunk, encoding, cb) {
  chunk = decodeChunk(state, chunk, encoding);

  if (Buffer.isBuffer(chunk)) encoding = 'buffer';
  var len = state.objectMode ? 1 : chunk.length;

  state.length += len;

  var ret = state.length < state.highWaterMark;
  // we must ensure that previous needDrain will not be reset to false.
  if (!ret) state.needDrain = true;

  if (state.writing || state.corked) {
    var last = state.lastBufferedRequest;
    state.lastBufferedRequest = new WriteReq(chunk, encoding, cb);
    if (last) {
      last.next = state.lastBufferedRequest;
    } else {
      state.bufferedRequest = state.lastBufferedRequest;
    }
    state.bufferedRequestCount += 1;
  } else {
    doWrite(stream, state, false, len, chunk, encoding, cb);
  }

  return ret;
}

function doWrite(stream, state, writev, len, chunk, encoding, cb) {
  state.writelen = len;
  state.writecb = cb;
  state.writing = true;
  state.sync = true;
  if (writev) stream._writev(chunk, state.onwrite);else stream._write(chunk, encoding, state.onwrite);
  state.sync = false;
}

function onwriteError(stream, state, sync, er, cb) {
  --state.pendingcb;
  if (sync) nextTick(cb, er);else cb(er);

  stream._writableState.errorEmitted = true;
  stream.emit('error', er);
}

function onwriteStateUpdate(state) {
  state.writing = false;
  state.writecb = null;
  state.length -= state.writelen;
  state.writelen = 0;
}

function onwrite(stream, er) {
  var state = stream._writableState;
  var sync = state.sync;
  var cb = state.writecb;

  onwriteStateUpdate(state);

  if (er) onwriteError(stream, state, sync, er, cb);else {
    // Check if we're actually ready to finish, but don't emit yet
    var finished = needFinish(state);

    if (!finished && !state.corked && !state.bufferProcessing && state.bufferedRequest) {
      clearBuffer(stream, state);
    }

    if (sync) {
      /*<replacement>*/
        nextTick(afterWrite, stream, state, finished, cb);
      /*</replacement>*/
    } else {
        afterWrite(stream, state, finished, cb);
      }
  }
}

function afterWrite(stream, state, finished, cb) {
  if (!finished) onwriteDrain(stream, state);
  state.pendingcb--;
  cb();
  finishMaybe(stream, state);
}

// Must force callback to be called on nextTick, so that we don't
// emit 'drain' before the write() consumer gets the 'false' return
// value, and has a chance to attach a 'drain' listener.
function onwriteDrain(stream, state) {
  if (state.length === 0 && state.needDrain) {
    state.needDrain = false;
    stream.emit('drain');
  }
}

// if there's something in the buffer waiting, then process it
function clearBuffer(stream, state) {
  state.bufferProcessing = true;
  var entry = state.bufferedRequest;

  if (stream._writev && entry && entry.next) {
    // Fast case, write everything using _writev()
    var l = state.bufferedRequestCount;
    var buffer = new Array(l);
    var holder = state.corkedRequestsFree;
    holder.entry = entry;

    var count = 0;
    while (entry) {
      buffer[count] = entry;
      entry = entry.next;
      count += 1;
    }

    doWrite(stream, state, true, state.length, buffer, '', holder.finish);

    // doWrite is almost always async, defer these to save a bit of time
    // as the hot path ends with doWrite
    state.pendingcb++;
    state.lastBufferedRequest = null;
    if (holder.next) {
      state.corkedRequestsFree = holder.next;
      holder.next = null;
    } else {
      state.corkedRequestsFree = new CorkedRequest(state);
    }
  } else {
    // Slow case, write chunks one-by-one
    while (entry) {
      var chunk = entry.chunk;
      var encoding = entry.encoding;
      var cb = entry.callback;
      var len = state.objectMode ? 1 : chunk.length;

      doWrite(stream, state, false, len, chunk, encoding, cb);
      entry = entry.next;
      // if we didn't call the onwrite immediately, then
      // it means that we need to wait until it does.
      // also, that means that the chunk and cb are currently
      // being processed, so move the buffer counter past them.
      if (state.writing) {
        break;
      }
    }

    if (entry === null) state.lastBufferedRequest = null;
  }

  state.bufferedRequestCount = 0;
  state.bufferedRequest = entry;
  state.bufferProcessing = false;
}

Writable.prototype._write = function (chunk, encoding, cb) {
  cb(new Error('not implemented'));
};

Writable.prototype._writev = null;

Writable.prototype.end = function (chunk, encoding, cb) {
  var state = this._writableState;

  if (typeof chunk === 'function') {
    cb = chunk;
    chunk = null;
    encoding = null;
  } else if (typeof encoding === 'function') {
    cb = encoding;
    encoding = null;
  }

  if (chunk !== null && chunk !== undefined) this.write(chunk, encoding);

  // .end() fully uncorks
  if (state.corked) {
    state.corked = 1;
    this.uncork();
  }

  // ignore unnecessary end() calls.
  if (!state.ending && !state.finished) endWritable(this, state, cb);
};

function needFinish(state) {
  return state.ending && state.length === 0 && state.bufferedRequest === null && !state.finished && !state.writing;
}

function prefinish(stream, state) {
  if (!state.prefinished) {
    state.prefinished = true;
    stream.emit('prefinish');
  }
}

function finishMaybe(stream, state) {
  var need = needFinish(state);
  if (need) {
    if (state.pendingcb === 0) {
      prefinish(stream, state);
      state.finished = true;
      stream.emit('finish');
    } else {
      prefinish(stream, state);
    }
  }
  return need;
}

function endWritable(stream, state, cb) {
  state.ending = true;
  finishMaybe(stream, state);
  if (cb) {
    if (state.finished) nextTick(cb);else stream.once('finish', cb);
  }
  state.ended = true;
  stream.writable = false;
}

// It seems a linked list but it is not
// there will be only 2 of these for each stream
function CorkedRequest(state) {
  var _this = this;

  this.next = null;
  this.entry = null;

  this.finish = function (err) {
    var entry = _this.entry;
    _this.entry = null;
    while (entry) {
      var cb = entry.callback;
      state.pendingcb--;
      cb(err);
      entry = entry.next;
    }
    if (state.corkedRequestsFree) {
      state.corkedRequestsFree.next = _this;
    } else {
      state.corkedRequestsFree = _this;
    }
  };
}

inherits$1(Duplex, Readable);

var keys = Object.keys(Writable.prototype);
for (var v = 0; v < keys.length; v++) {
  var method = keys[v];
  if (!Duplex.prototype[method]) Duplex.prototype[method] = Writable.prototype[method];
}
function Duplex(options) {
  if (!(this instanceof Duplex)) return new Duplex(options);

  Readable.call(this, options);
  Writable.call(this, options);

  if (options && options.readable === false) this.readable = false;

  if (options && options.writable === false) this.writable = false;

  this.allowHalfOpen = true;
  if (options && options.allowHalfOpen === false) this.allowHalfOpen = false;

  this.once('end', onend);
}

// the no-half-open enforcer
function onend() {
  // if we allow half-open state, or if the writable side ended,
  // then we're ok.
  if (this.allowHalfOpen || this._writableState.ended) return;

  // no more data can be written.
  // But allow more writes to happen in this tick.
  nextTick(onEndNT, this);
}

function onEndNT(self) {
  self.end();
}

// a transform stream is a readable/writable stream where you do
inherits$1(Transform, Duplex);

function TransformState(stream) {
  this.afterTransform = function (er, data) {
    return afterTransform(stream, er, data);
  };

  this.needTransform = false;
  this.transforming = false;
  this.writecb = null;
  this.writechunk = null;
  this.writeencoding = null;
}

function afterTransform(stream, er, data) {
  var ts = stream._transformState;
  ts.transforming = false;

  var cb = ts.writecb;

  if (!cb) return stream.emit('error', new Error('no writecb in Transform class'));

  ts.writechunk = null;
  ts.writecb = null;

  if (data !== null && data !== undefined) stream.push(data);

  cb(er);

  var rs = stream._readableState;
  rs.reading = false;
  if (rs.needReadable || rs.length < rs.highWaterMark) {
    stream._read(rs.highWaterMark);
  }
}
function Transform(options) {
  if (!(this instanceof Transform)) return new Transform(options);

  Duplex.call(this, options);

  this._transformState = new TransformState(this);

  // when the writable side finishes, then flush out anything remaining.
  var stream = this;

  // start out asking for a readable event once data is transformed.
  this._readableState.needReadable = true;

  // we have implemented the _read method, and done the other things
  // that Readable wants before the first _read call, so unset the
  // sync guard flag.
  this._readableState.sync = false;

  if (options) {
    if (typeof options.transform === 'function') this._transform = options.transform;

    if (typeof options.flush === 'function') this._flush = options.flush;
  }

  this.once('prefinish', function () {
    if (typeof this._flush === 'function') this._flush(function (er) {
      done(stream, er);
    });else done(stream);
  });
}

Transform.prototype.push = function (chunk, encoding) {
  this._transformState.needTransform = false;
  return Duplex.prototype.push.call(this, chunk, encoding);
};

// This is the part where you do stuff!
// override this function in implementation classes.
// 'chunk' is an input chunk.
//
// Call `push(newChunk)` to pass along transformed output
// to the readable side.  You may call 'push' zero or more times.
//
// Call `cb(err)` when you are done with this chunk.  If you pass
// an error, then that'll put the hurt on the whole operation.  If you
// never call cb(), then you'll never get another chunk.
Transform.prototype._transform = function (chunk, encoding, cb) {
  throw new Error('Not implemented');
};

Transform.prototype._write = function (chunk, encoding, cb) {
  var ts = this._transformState;
  ts.writecb = cb;
  ts.writechunk = chunk;
  ts.writeencoding = encoding;
  if (!ts.transforming) {
    var rs = this._readableState;
    if (ts.needTransform || rs.needReadable || rs.length < rs.highWaterMark) this._read(rs.highWaterMark);
  }
};

// Doesn't matter what the args are here.
// _transform does all the work.
// That we got here means that the readable side wants more data.
Transform.prototype._read = function (n) {
  var ts = this._transformState;

  if (ts.writechunk !== null && ts.writecb && !ts.transforming) {
    ts.transforming = true;
    this._transform(ts.writechunk, ts.writeencoding, ts.afterTransform);
  } else {
    // mark that we need a transform, so that any data that comes in
    // will get processed, now that we've asked for it.
    ts.needTransform = true;
  }
};

function done(stream, er) {
  if (er) return stream.emit('error', er);

  // if there's nothing in the write buffer, then that means
  // that nothing more will ever be provided
  var ws = stream._writableState;
  var ts = stream._transformState;

  if (ws.length) throw new Error('Calling transform done when ws.length != 0');

  if (ts.transforming) throw new Error('Calling transform done when still transforming');

  return stream.push(null);
}

inherits$1(PassThrough, Transform);
function PassThrough(options) {
  if (!(this instanceof PassThrough)) return new PassThrough(options);

  Transform.call(this, options);
}

PassThrough.prototype._transform = function (chunk, encoding, cb) {
  cb(null, chunk);
};

inherits$1(Stream, EventEmitter);
Stream.Readable = Readable;
Stream.Writable = Writable;
Stream.Duplex = Duplex;
Stream.Transform = Transform;
Stream.PassThrough = PassThrough;

// Backwards-compat with node 0.4.x
Stream.Stream = Stream;

// old-style streams.  Note that the pipe method (the only relevant
// part of this class) is overridden in the Readable class.

function Stream() {
  EventEmitter.call(this);
}

Stream.prototype.pipe = function(dest, options) {
  var source = this;

  function ondata(chunk) {
    if (dest.writable) {
      if (false === dest.write(chunk) && source.pause) {
        source.pause();
      }
    }
  }

  source.on('data', ondata);

  function ondrain() {
    if (source.readable && source.resume) {
      source.resume();
    }
  }

  dest.on('drain', ondrain);

  // If the 'end' option is not supplied, dest.end() will be called when
  // source gets the 'end' or 'close' events.  Only dest.end() once.
  if (!dest._isStdio && (!options || options.end !== false)) {
    source.on('end', onend);
    source.on('close', onclose);
  }

  var didOnEnd = false;
  function onend() {
    if (didOnEnd) return;
    didOnEnd = true;

    dest.end();
  }


  function onclose() {
    if (didOnEnd) return;
    didOnEnd = true;

    if (typeof dest.destroy === 'function') dest.destroy();
  }

  // don't leave dangling pipes when there are errors.
  function onerror(er) {
    cleanup();
    if (EventEmitter.listenerCount(this, 'error') === 0) {
      throw er; // Unhandled stream error in pipe.
    }
  }

  source.on('error', onerror);
  dest.on('error', onerror);

  // remove all the event listeners that were added.
  function cleanup() {
    source.removeListener('data', ondata);
    dest.removeListener('drain', ondrain);

    source.removeListener('end', onend);
    source.removeListener('close', onclose);

    source.removeListener('error', onerror);
    dest.removeListener('error', onerror);

    source.removeListener('end', cleanup);
    source.removeListener('close', cleanup);

    dest.removeListener('close', cleanup);
  }

  source.on('end', cleanup);
  source.on('close', cleanup);

  dest.on('close', cleanup);

  dest.emit('pipe', source);

  // Allow for unix-like usage: A.pipe(B).pipe(C)
  return dest;
};

class ResizeableBuffer{
  constructor(size=100){
    this.size = size;
    this.length = 0;
    this.buf = Buffer.alloc(size);
  }
  prepend(val){
    if(isBuffer(val)){
      const length = this.length + val.length;
      if(length >= this.size){
        this.resize();
        if(length >= this.size){
          throw Error('INVALID_BUFFER_STATE');
        }
      }
      const buf = this.buf;
      this.buf = Buffer.alloc(this.size);
      val.copy(this.buf, 0);
      buf.copy(this.buf, val.length);
      this.length += val.length;
    }else {
      const length = this.length++;
      if(length === this.size){
        this.resize();
      }
      const buf = this.clone();
      this.buf[0] = val;
      buf.copy(this.buf,1, 0, length);
    }
  }
  append(val){
    const length = this.length++;
    if(length === this.size){
      this.resize();
    }
    this.buf[length] = val;
  }
  clone(){
    return Buffer.from(this.buf.slice(0, this.length));
  }
  resize(){
    const length = this.length;
    this.size = this.size * 2;
    const buf = Buffer.alloc(this.size);
    this.buf.copy(buf,0, 0, length);
    this.buf = buf;
  }
  toString(encoding){
    if(encoding){
      return this.buf.slice(0, this.length).toString(encoding);
    }else {
      return Uint8Array.prototype.slice.call(this.buf.slice(0, this.length));
    }
  }
  toJSON(){
    return this.toString('utf8');
  }
  reset(){
    this.length = 0;
  }
}

// white space characters
// https://en.wikipedia.org/wiki/Whitespace_character
// https://developer.mozilla.org/en-US/docs/Web/JavaScript/Guide/Regular_Expressions/Character_Classes#Types
// \f\n\r\t\v\u00a0\u1680\u2000-\u200a\u2028\u2029\u202f\u205f\u3000\ufeff
const tab = 9;
const nl = 10; // \n, 0x0A in hexadecimal, 10 in decimal
const np = 12;
const cr = 13; // \r, 0x0D in hexadécimal, 13 in decimal
const space = 32;
const boms = {
  // Note, the following are equals:
  // Buffer.from("\ufeff")
  // Buffer.from([239, 187, 191])
  // Buffer.from('EFBBBF', 'hex')
  'utf8': Buffer.from([239, 187, 191]),
  // Note, the following are equals:
  // Buffer.from "\ufeff", 'utf16le
  // Buffer.from([255, 254])
  'utf16le': Buffer.from([255, 254])
};

class CsvError extends Error {
  constructor(code, message, options, ...contexts) {
    if(Array.isArray(message)) message = message.join(' ');
    super(message);
    if(Error.captureStackTrace !== undefined){
      Error.captureStackTrace(this, CsvError);
    }
    this.code = code;
    for(const context of contexts){
      for(const key in context){
        const value = context[key];
        this[key] = isBuffer(value) ? value.toString(options.encoding) : value == null ? value : JSON.parse(JSON.stringify(value));
      }
    }
  }
}

const underscore = function(str){
  return str.replace(/([A-Z])/g, function(_, match){
    return '_' + match.toLowerCase();
  });
};

const isObject = function(obj){
  return (typeof obj === 'object' && obj !== null && !Array.isArray(obj));
};

const isRecordEmpty = function(record){
  return record.every((field) => field == null || field.toString && field.toString().trim() === '');
};

const normalizeColumnsArray = function(columns){
  const normalizedColumns = [];
  for(let i = 0, l = columns.length; i < l; i++){
    const column = columns[i];
    if(column === undefined || column === null || column === false){
      normalizedColumns[i] = { disabled: true };
    }else if(typeof column === 'string'){
      normalizedColumns[i] = { name: column };
    }else if(isObject(column)){
      if(typeof column.name !== 'string'){
        throw new CsvError('CSV_OPTION_COLUMNS_MISSING_NAME', [
          'Option columns missing name:',
          `property "name" is required at position ${i}`,
          'when column is an object literal'
        ]);
      }
      normalizedColumns[i] = column;
    }else {
      throw new CsvError('CSV_INVALID_COLUMN_DEFINITION', [
        'Invalid column definition:',
        'expect a string or a literal object,',
        `got ${JSON.stringify(column)} at position ${i}`
      ]);
    }
  }
  return normalizedColumns;
};

class Parser extends Transform {
  constructor(opts = {}){
    super({...{readableObjectMode: true}, ...opts, encoding: null});
    this.__originalOptions = opts;
    this.__normalizeOptions(opts);
  }
  __normalizeOptions(opts){
    const options = {};
    // Merge with user options
    for(const opt in opts){
      options[underscore(opt)] = opts[opt];
    }
    // Normalize option `encoding`
    // Note: defined first because other options depends on it
    // to convert chars/strings into buffers.
    if(options.encoding === undefined || options.encoding === true){
      options.encoding = 'utf8';
    }else if(options.encoding === null || options.encoding === false){
      options.encoding = null;
    }else if(typeof options.encoding !== 'string' && options.encoding !== null){
      throw new CsvError('CSV_INVALID_OPTION_ENCODING', [
        'Invalid option encoding:',
        'encoding must be a string or null to return a buffer,',
        `got ${JSON.stringify(options.encoding)}`
      ], options);
    }
    // Normalize option `bom`
    if(options.bom === undefined || options.bom === null || options.bom === false){
      options.bom = false;
    }else if(options.bom !== true){
      throw new CsvError('CSV_INVALID_OPTION_BOM', [
        'Invalid option bom:', 'bom must be true,',
        `got ${JSON.stringify(options.bom)}`
      ], options);
    }
    // Normalize option `cast`
    let fnCastField = null;
    if(options.cast === undefined || options.cast === null || options.cast === false || options.cast === ''){
      options.cast = undefined;
    }else if(typeof options.cast === 'function'){
      fnCastField = options.cast;
      options.cast = true;
    }else if(options.cast !== true){
      throw new CsvError('CSV_INVALID_OPTION_CAST', [
        'Invalid option cast:', 'cast must be true or a function,',
        `got ${JSON.stringify(options.cast)}`
      ], options);
    }
    // Normalize option `cast_date`
    if(options.cast_date === undefined || options.cast_date === null || options.cast_date === false || options.cast_date === ''){
      options.cast_date = false;
    }else if(options.cast_date === true){
      options.cast_date = function(value){
        const date = Date.parse(value);
        return !isNaN(date) ? new Date(date) : value;
      };
    }else {
      throw new CsvError('CSV_INVALID_OPTION_CAST_DATE', [
        'Invalid option cast_date:', 'cast_date must be true or a function,',
        `got ${JSON.stringify(options.cast_date)}`
      ], options);
    }
    // Normalize option `columns`
    let fnFirstLineToHeaders = null;
    if(options.columns === true){
      // Fields in the first line are converted as-is to columns
      fnFirstLineToHeaders = undefined;
    }else if(typeof options.columns === 'function'){
      fnFirstLineToHeaders = options.columns;
      options.columns = true;
    }else if(Array.isArray(options.columns)){
      options.columns = normalizeColumnsArray(options.columns);
    }else if(options.columns === undefined || options.columns === null || options.columns === false){
      options.columns = false;
    }else {
      throw new CsvError('CSV_INVALID_OPTION_COLUMNS', [
        'Invalid option columns:',
        'expect an array, a function or true,',
        `got ${JSON.stringify(options.columns)}`
      ], options);
    }
    // Normalize option `columns_duplicates_to_array`
    if(options.columns_duplicates_to_array === undefined || options.columns_duplicates_to_array === null || options.columns_duplicates_to_array === false){
      options.columns_duplicates_to_array = false;
    }else if(options.columns_duplicates_to_array !== true){
      throw new CsvError('CSV_INVALID_OPTION_COLUMNS_DUPLICATES_TO_ARRAY', [
        'Invalid option columns_duplicates_to_array:',
        'expect an boolean,',
        `got ${JSON.stringify(options.columns_duplicates_to_array)}`
      ], options);
    }else if(options.columns === false){
      throw new CsvError('CSV_INVALID_OPTION_COLUMNS_DUPLICATES_TO_ARRAY', [
        'Invalid option columns_duplicates_to_array:',
        'the `columns` mode must be activated.'
      ], options);
    }
    // Normalize option `comment`
    if(options.comment === undefined || options.comment === null || options.comment === false || options.comment === ''){
      options.comment = null;
    }else {
      if(typeof options.comment === 'string'){
        options.comment = Buffer.from(options.comment, options.encoding);
      }
      if(!isBuffer(options.comment)){
        throw new CsvError('CSV_INVALID_OPTION_COMMENT', [
          'Invalid option comment:',
          'comment must be a buffer or a string,',
          `got ${JSON.stringify(options.comment)}`
        ], options);
      }
    }
    // Normalize option `delimiter`
    const delimiter_json = JSON.stringify(options.delimiter);
    if(!Array.isArray(options.delimiter)) options.delimiter = [options.delimiter];
    if(options.delimiter.length === 0){
      throw new CsvError('CSV_INVALID_OPTION_DELIMITER', [
        'Invalid option delimiter:',
        'delimiter must be a non empty string or buffer or array of string|buffer,',
        `got ${delimiter_json}`
      ], options);
    }
    options.delimiter = options.delimiter.map(function(delimiter){
      if(delimiter === undefined || delimiter === null || delimiter === false){
        return Buffer.from(',', options.encoding);
      }
      if(typeof delimiter === 'string'){
        delimiter = Buffer.from(delimiter, options.encoding);
      }
      if(!isBuffer(delimiter) || delimiter.length === 0){
        throw new CsvError('CSV_INVALID_OPTION_DELIMITER', [
          'Invalid option delimiter:',
          'delimiter must be a non empty string or buffer or array of string|buffer,',
          `got ${delimiter_json}`
        ], options);
      }
      return delimiter;
    });
    // Normalize option `escape`
    if(options.escape === undefined || options.escape === true){
      options.escape = Buffer.from('"', options.encoding);
    }else if(typeof options.escape === 'string'){
      options.escape = Buffer.from(options.escape, options.encoding);
    }else if (options.escape === null || options.escape === false){
      options.escape = null;
    }
    if(options.escape !== null){
      if(!isBuffer(options.escape)){
        throw new Error(`Invalid Option: escape must be a buffer, a string or a boolean, got ${JSON.stringify(options.escape)}`);
      }
    }
    // Normalize option `from`
    if(options.from === undefined || options.from === null){
      options.from = 1;
    }else {
      if(typeof options.from === 'string' && /\d+/.test(options.from)){
        options.from = parseInt(options.from);
      }
      if(Number.isInteger(options.from)){
        if(options.from < 0){
          throw new Error(`Invalid Option: from must be a positive integer, got ${JSON.stringify(opts.from)}`);
        }
      }else {
        throw new Error(`Invalid Option: from must be an integer, got ${JSON.stringify(options.from)}`);
      }
    }
    // Normalize option `from_line`
    if(options.from_line === undefined || options.from_line === null){
      options.from_line = 1;
    }else {
      if(typeof options.from_line === 'string' && /\d+/.test(options.from_line)){
        options.from_line = parseInt(options.from_line);
      }
      if(Number.isInteger(options.from_line)){
        if(options.from_line <= 0){
          throw new Error(`Invalid Option: from_line must be a positive integer greater than 0, got ${JSON.stringify(opts.from_line)}`);
        }
      }else {
        throw new Error(`Invalid Option: from_line must be an integer, got ${JSON.stringify(opts.from_line)}`);
      }
    }
    // Normalize options `ignore_last_delimiters`
    if(options.ignore_last_delimiters === undefined || options.ignore_last_delimiters === null){
      options.ignore_last_delimiters = false;
    }else if(typeof options.ignore_last_delimiters === 'number'){
      options.ignore_last_delimiters = Math.floor(options.ignore_last_delimiters);
      if(options.ignore_last_delimiters === 0){
        options.ignore_last_delimiters = false;
      }
    }else if(typeof options.ignore_last_delimiters !== 'boolean'){
      throw new CsvError('CSV_INVALID_OPTION_IGNORE_LAST_DELIMITERS', [
        'Invalid option `ignore_last_delimiters`:',
        'the value must be a boolean value or an integer,',
        `got ${JSON.stringify(options.ignore_last_delimiters)}`
      ], options);
    }
    if(options.ignore_last_delimiters === true && options.columns === false){
      throw new CsvError('CSV_IGNORE_LAST_DELIMITERS_REQUIRES_COLUMNS', [
        'The option `ignore_last_delimiters`',
        'requires the activation of the `columns` option'
      ], options);
    }
    // Normalize option `info`
    if(options.info === undefined || options.info === null || options.info === false){
      options.info = false;
    }else if(options.info !== true){
      throw new Error(`Invalid Option: info must be true, got ${JSON.stringify(options.info)}`);
    }
    // Normalize option `max_record_size`
    if(options.max_record_size === undefined || options.max_record_size === null || options.max_record_size === false){
      options.max_record_size = 0;
    }else if(Number.isInteger(options.max_record_size) && options.max_record_size >= 0);else if(typeof options.max_record_size === 'string' && /\d+/.test(options.max_record_size)){
      options.max_record_size = parseInt(options.max_record_size);
    }else {
      throw new Error(`Invalid Option: max_record_size must be a positive integer, got ${JSON.stringify(options.max_record_size)}`);
    }
    // Normalize option `objname`
    if(options.objname === undefined || options.objname === null || options.objname === false){
      options.objname = undefined;
    }else if(isBuffer(options.objname)){
      if(options.objname.length === 0){
        throw new Error(`Invalid Option: objname must be a non empty buffer`);
      }
      if(options.encoding === null);else {
        options.objname = options.objname.toString(options.encoding);
      }
    }else if(typeof options.objname === 'string'){
      if(options.objname.length === 0){
        throw new Error(`Invalid Option: objname must be a non empty string`);
      }
      // Great, nothing to do
    }else {
      throw new Error(`Invalid Option: objname must be a string or a buffer, got ${options.objname}`);
    }
    // Normalize option `on_record`
    if(options.on_record === undefined || options.on_record === null){
      options.on_record = undefined;
    }else if(typeof options.on_record !== 'function'){
      throw new CsvError('CSV_INVALID_OPTION_ON_RECORD', [
        'Invalid option `on_record`:',
        'expect a function,',
        `got ${JSON.stringify(options.on_record)}`
      ], options);
    }
    // Normalize option `quote`
    if(options.quote === null || options.quote === false || options.quote === ''){
      options.quote = null;
    }else {
      if(options.quote === undefined || options.quote === true){
        options.quote = Buffer.from('"', options.encoding);
      }else if(typeof options.quote === 'string'){
        options.quote = Buffer.from(options.quote, options.encoding);
      }
      if(!isBuffer(options.quote)){
        throw new Error(`Invalid Option: quote must be a buffer or a string, got ${JSON.stringify(options.quote)}`);
      }
    }
    // Normalize option `raw`
    if(options.raw === undefined || options.raw === null || options.raw === false){
      options.raw = false;
    }else if(options.raw !== true){
      throw new Error(`Invalid Option: raw must be true, got ${JSON.stringify(options.raw)}`);
    }
    // Normalize option `record_delimiter`
    if(!options.record_delimiter){
      options.record_delimiter = [];
    }else if(!Array.isArray(options.record_delimiter)){
      options.record_delimiter = [options.record_delimiter];
    }
    options.record_delimiter = options.record_delimiter.map(function(rd){
      if(typeof rd === 'string'){
        rd = Buffer.from(rd, options.encoding);
      }
      return rd;
    });
    // Normalize option `relax`
    if(typeof options.relax === 'boolean');else if(options.relax === undefined || options.relax === null){
      options.relax = false;
    }else {
      throw new Error(`Invalid Option: relax must be a boolean, got ${JSON.stringify(options.relax)}`);
    }
    // Normalize option `relax_column_count`
    if(typeof options.relax_column_count === 'boolean');else if(options.relax_column_count === undefined || options.relax_column_count === null){
      options.relax_column_count = false;
    }else {
      throw new Error(`Invalid Option: relax_column_count must be a boolean, got ${JSON.stringify(options.relax_column_count)}`);
    }
    if(typeof options.relax_column_count_less === 'boolean');else if(options.relax_column_count_less === undefined || options.relax_column_count_less === null){
      options.relax_column_count_less = false;
    }else {
      throw new Error(`Invalid Option: relax_column_count_less must be a boolean, got ${JSON.stringify(options.relax_column_count_less)}`);
    }
    if(typeof options.relax_column_count_more === 'boolean');else if(options.relax_column_count_more === undefined || options.relax_column_count_more === null){
      options.relax_column_count_more = false;
    }else {
      throw new Error(`Invalid Option: relax_column_count_more must be a boolean, got ${JSON.stringify(options.relax_column_count_more)}`);
    }
    // Normalize option `skip_empty_lines`
    if(typeof options.skip_empty_lines === 'boolean');else if(options.skip_empty_lines === undefined || options.skip_empty_lines === null){
      options.skip_empty_lines = false;
    }else {
      throw new Error(`Invalid Option: skip_empty_lines must be a boolean, got ${JSON.stringify(options.skip_empty_lines)}`);
    }
    // Normalize option `skip_lines_with_empty_values`
    if(typeof options.skip_lines_with_empty_values === 'boolean');else if(options.skip_lines_with_empty_values === undefined || options.skip_lines_with_empty_values === null){
      options.skip_lines_with_empty_values = false;
    }else {
      throw new Error(`Invalid Option: skip_lines_with_empty_values must be a boolean, got ${JSON.stringify(options.skip_lines_with_empty_values)}`);
    }
    // Normalize option `skip_lines_with_error`
    if(typeof options.skip_lines_with_error === 'boolean');else if(options.skip_lines_with_error === undefined || options.skip_lines_with_error === null){
      options.skip_lines_with_error = false;
    }else {
      throw new Error(`Invalid Option: skip_lines_with_error must be a boolean, got ${JSON.stringify(options.skip_lines_with_error)}`);
    }
    // Normalize option `rtrim`
    if(options.rtrim === undefined || options.rtrim === null || options.rtrim === false){
      options.rtrim = false;
    }else if(options.rtrim !== true){
      throw new Error(`Invalid Option: rtrim must be a boolean, got ${JSON.stringify(options.rtrim)}`);
    }
    // Normalize option `ltrim`
    if(options.ltrim === undefined || options.ltrim === null || options.ltrim === false){
      options.ltrim = false;
    }else if(options.ltrim !== true){
      throw new Error(`Invalid Option: ltrim must be a boolean, got ${JSON.stringify(options.ltrim)}`);
    }
    // Normalize option `trim`
    if(options.trim === undefined || options.trim === null || options.trim === false){
      options.trim = false;
    }else if(options.trim !== true){
      throw new Error(`Invalid Option: trim must be a boolean, got ${JSON.stringify(options.trim)}`);
    }
    // Normalize options `trim`, `ltrim` and `rtrim`
    if(options.trim === true && opts.ltrim !== false){
      options.ltrim = true;
    }else if(options.ltrim !== true){
      options.ltrim = false;
    }
    if(options.trim === true && opts.rtrim !== false){
      options.rtrim = true;
    }else if(options.rtrim !== true){
      options.rtrim = false;
    }
    // Normalize option `to`
    if(options.to === undefined || options.to === null){
      options.to = -1;
    }else {
      if(typeof options.to === 'string' && /\d+/.test(options.to)){
        options.to = parseInt(options.to);
      }
      if(Number.isInteger(options.to)){
        if(options.to <= 0){
          throw new Error(`Invalid Option: to must be a positive integer greater than 0, got ${JSON.stringify(opts.to)}`);
        }
      }else {
        throw new Error(`Invalid Option: to must be an integer, got ${JSON.stringify(opts.to)}`);
      }
    }
    // Normalize option `to_line`
    if(options.to_line === undefined || options.to_line === null){
      options.to_line = -1;
    }else {
      if(typeof options.to_line === 'string' && /\d+/.test(options.to_line)){
        options.to_line = parseInt(options.to_line);
      }
      if(Number.isInteger(options.to_line)){
        if(options.to_line <= 0){
          throw new Error(`Invalid Option: to_line must be a positive integer greater than 0, got ${JSON.stringify(opts.to_line)}`);
        }
      }else {
        throw new Error(`Invalid Option: to_line must be an integer, got ${JSON.stringify(opts.to_line)}`);
      }
    }
    this.info = {
      bytes: 0,
      comment_lines: 0,
      empty_lines: 0,
      invalid_field_length: 0,
      lines: 1,
      records: 0
    };
    this.options = options;
    this.state = {
      bomSkipped: false,
      bufBytesStart: 0,
      castField: fnCastField,
      commenting: false,
      // Current error encountered by a record
      error: undefined,
      enabled: options.from_line === 1,
      escaping: false,
      // escapeIsQuote: options.escape === options.quote,
      escapeIsQuote: isBuffer(options.escape) && isBuffer(options.quote) && Buffer.compare(options.escape, options.quote) === 0,
      // columns can be `false`, `true`, `Array`
      expectedRecordLength: Array.isArray(options.columns) ? options.columns.length : undefined,
      field: new ResizeableBuffer(20),
      firstLineToHeaders: fnFirstLineToHeaders,
      needMoreDataSize: Math.max(
        // Skip if the remaining buffer smaller than comment
        options.comment !== null ? options.comment.length : 0,
        // Skip if the remaining buffer can be delimiter
        ...options.delimiter.map((delimiter) => delimiter.length),
        // Skip if the remaining buffer can be escape sequence
        options.quote !== null ? options.quote.length : 0,
      ),
      previousBuf: undefined,
      quoting: false,
      stop: false,
      rawBuffer: new ResizeableBuffer(100),
      record: [],
      recordHasError: false,
      record_length: 0,
      recordDelimiterMaxLength: options.record_delimiter.length === 0 ? 2 : Math.max(...options.record_delimiter.map((v) => v.length)),
      trimChars: [Buffer.from(' ', options.encoding)[0], Buffer.from('\t', options.encoding)[0]],
      wasQuoting: false,
      wasRowDelimiter: false
    };
  }
  // Implementation of `Transform._transform`
  _transform(buf, encoding, callback){
    if(this.state.stop === true){
      return;
    }
    const err = this.__parse(buf, false);
    if(err !== undefined){
      this.state.stop = true;
    }
    callback(err);
  }
  // Implementation of `Transform._flush`
  _flush(callback){
    if(this.state.stop === true){
      return;
    }
    const err = this.__parse(undefined, true);
    callback(err);
  }
  // Central parser implementation
  __parse(nextBuf, end){
    const {bom, comment, escape, from_line, ltrim, max_record_size, quote, raw, relax, rtrim, skip_empty_lines, to, to_line} = this.options;
    let {record_delimiter} = this.options;
    const {bomSkipped, previousBuf, rawBuffer, escapeIsQuote} = this.state;
    let buf;
    if(previousBuf === undefined){
      if(nextBuf === undefined){
        // Handle empty string
        this.push(null);
        return;
      }else {
        buf = nextBuf;
      }
    }else if(previousBuf !== undefined && nextBuf === undefined){
      buf = previousBuf;
    }else {
      buf = Buffer.concat([previousBuf, nextBuf]);
    }
    // Handle UTF BOM
    if(bomSkipped === false){
      if(bom === false){
        this.state.bomSkipped = true;
      }else if(buf.length < 3){
        // No enough data
        if(end === false){
          // Wait for more data
          this.state.previousBuf = buf;
          return;
        }
      }else {
        for(const encoding in boms){
          if(boms[encoding].compare(buf, 0, boms[encoding].length) === 0){
            // Skip BOM
            const bomLength = boms[encoding].length;
            this.state.bufBytesStart += bomLength;
            buf = buf.slice(bomLength);
            // Renormalize original options with the new encoding
            this.__normalizeOptions({...this.__originalOptions, encoding: encoding});
            break;
          }
        }
        this.state.bomSkipped = true;
      }
    }
    const bufLen = buf.length;
    let pos;
    for(pos = 0; pos < bufLen; pos++){
      // Ensure we get enough space to look ahead
      // There should be a way to move this out of the loop
      if(this.__needMoreData(pos, bufLen, end)){
        break;
      }
      if(this.state.wasRowDelimiter === true){
        this.info.lines++;
        this.state.wasRowDelimiter = false;
      }
      if(to_line !== -1 && this.info.lines > to_line){
        this.state.stop = true;
        this.push(null);
        return;
      }
      // Auto discovery of record_delimiter, unix, mac and windows supported
      if(this.state.quoting === false && record_delimiter.length === 0){
        const record_delimiterCount = this.__autoDiscoverRecordDelimiter(buf, pos);
        if(record_delimiterCount){
          record_delimiter = this.options.record_delimiter;
        }
      }
      const chr = buf[pos];
      if(raw === true){
        rawBuffer.append(chr);
      }
      if((chr === cr || chr === nl) && this.state.wasRowDelimiter === false){
        this.state.wasRowDelimiter = true;
      }
      // Previous char was a valid escape char
      // treat the current char as a regular char
      if(this.state.escaping === true){
        this.state.escaping = false;
      }else {
        // Escape is only active inside quoted fields
        // We are quoting, the char is an escape chr and there is a chr to escape
        // if(escape !== null && this.state.quoting === true && chr === escape && pos + 1 < bufLen){
        if(escape !== null && this.state.quoting === true && this.__isEscape(buf, pos, chr) && pos + escape.length < bufLen){
          if(escapeIsQuote){
            if(this.__isQuote(buf, pos+escape.length)){
              this.state.escaping = true;
              pos += escape.length - 1;
              continue;
            }
          }else {
            this.state.escaping = true;
            pos += escape.length - 1;
            continue;
          }
        }
        // Not currently escaping and chr is a quote
        // TODO: need to compare bytes instead of single char
        if(this.state.commenting === false && this.__isQuote(buf, pos)){
          if(this.state.quoting === true){
            const nextChr = buf[pos+quote.length];
            const isNextChrTrimable = rtrim && this.__isCharTrimable(nextChr);
            const isNextChrComment = comment !== null && this.__compareBytes(comment, buf, pos+quote.length, nextChr);
            const isNextChrDelimiter = this.__isDelimiter(buf, pos+quote.length, nextChr);
            const isNextChrRecordDelimiter = record_delimiter.length === 0 ? this.__autoDiscoverRecordDelimiter(buf, pos+quote.length) : this.__isRecordDelimiter(nextChr, buf, pos+quote.length);
            // Escape a quote
            // Treat next char as a regular character
            if(escape !== null && this.__isEscape(buf, pos, chr) && this.__isQuote(buf, pos + escape.length)){
              pos += escape.length - 1;
            }else if(!nextChr || isNextChrDelimiter || isNextChrRecordDelimiter || isNextChrComment || isNextChrTrimable){
              this.state.quoting = false;
              this.state.wasQuoting = true;
              pos += quote.length - 1;
              continue;
            }else if(relax === false){
              const err = this.__error(
                new CsvError('CSV_INVALID_CLOSING_QUOTE', [
                  'Invalid Closing Quote:',
                  `got "${String.fromCharCode(nextChr)}"`,
                  `at line ${this.info.lines}`,
                  'instead of delimiter, record delimiter, trimable character',
                  '(if activated) or comment',
                ], this.options, this.__infoField())
              );
              if(err !== undefined) return err;
            }else {
              this.state.quoting = false;
              this.state.wasQuoting = true;
              this.state.field.prepend(quote);
              pos += quote.length - 1;
            }
          }else {
            if(this.state.field.length !== 0){
              // In relax mode, treat opening quote preceded by chrs as regular
              if(relax === false){
                const err = this.__error(
                  new CsvError('INVALID_OPENING_QUOTE', [
                    'Invalid Opening Quote:',
                    `a quote is found inside a field at line ${this.info.lines}`,
                  ], this.options, this.__infoField(), {
                    field: this.state.field,
                  })
                );
                if(err !== undefined) return err;
              }
            }else {
              this.state.quoting = true;
              pos += quote.length - 1;
              continue;
            }
          }
        }
        if(this.state.quoting === false){
          const recordDelimiterLength = this.__isRecordDelimiter(chr, buf, pos);
          if(recordDelimiterLength !== 0){
            // Do not emit comments which take a full line
            const skipCommentLine = this.state.commenting && (this.state.wasQuoting === false && this.state.record.length === 0 && this.state.field.length === 0);
            if(skipCommentLine){
              this.info.comment_lines++;
              // Skip full comment line
            }else {
              // Activate records emition if above from_line
              if(this.state.enabled === false && this.info.lines + (this.state.wasRowDelimiter === true ? 1: 0) >= from_line){
                this.state.enabled = true;
                this.__resetField();
                this.__resetRecord();
                pos += recordDelimiterLength - 1;
                continue;
              }
              // Skip if line is empty and skip_empty_lines activated
              if(skip_empty_lines === true && this.state.wasQuoting === false && this.state.record.length === 0 && this.state.field.length === 0){
                this.info.empty_lines++;
                pos += recordDelimiterLength - 1;
                continue;
              }
              this.info.bytes = this.state.bufBytesStart + pos;
              const errField = this.__onField();
              if(errField !== undefined) return errField;
              this.info.bytes = this.state.bufBytesStart + pos + recordDelimiterLength;
              const errRecord = this.__onRecord();
              if(errRecord !== undefined) return errRecord;
              if(to !== -1 && this.info.records >= to){
                this.state.stop = true;
                this.push(null);
                return;
              }
            }
            this.state.commenting = false;
            pos += recordDelimiterLength - 1;
            continue;
          }
          if(this.state.commenting){
            continue;
          }
          const commentCount = comment === null ? 0 : this.__compareBytes(comment, buf, pos, chr);
          if(commentCount !== 0){
            this.state.commenting = true;
            continue;
          }
          const delimiterLength = this.__isDelimiter(buf, pos, chr);
          if(delimiterLength !== 0){
            this.info.bytes = this.state.bufBytesStart + pos;
            const errField = this.__onField();
            if(errField !== undefined) return errField;
            pos += delimiterLength - 1;
            continue;
          }
        }
      }
      if(this.state.commenting === false){
        if(max_record_size !== 0 && this.state.record_length + this.state.field.length > max_record_size){
          const err = this.__error(
            new CsvError('CSV_MAX_RECORD_SIZE', [
              'Max Record Size:',
              'record exceed the maximum number of tolerated bytes',
              `of ${max_record_size}`,
              `at line ${this.info.lines}`,
            ], this.options, this.__infoField())
          );
          if(err !== undefined) return err;
        }
      }
      const lappend = ltrim === false || this.state.quoting === true || this.state.field.length !== 0 || !this.__isCharTrimable(chr);
      // rtrim in non quoting is handle in __onField
      const rappend = rtrim === false || this.state.wasQuoting === false;
      if(lappend === true && rappend === true){
        this.state.field.append(chr);
      }else if(rtrim === true && !this.__isCharTrimable(chr)){
        const err = this.__error(
          new CsvError('CSV_NON_TRIMABLE_CHAR_AFTER_CLOSING_QUOTE', [
            'Invalid Closing Quote:',
            'found non trimable byte after quote',
            `at line ${this.info.lines}`,
          ], this.options, this.__infoField())
        );
        if(err !== undefined) return err;
      }
    }
    if(end === true){
      // Ensure we are not ending in a quoting state
      if(this.state.quoting === true){
        const err = this.__error(
          new CsvError('CSV_QUOTE_NOT_CLOSED', [
            'Quote Not Closed:',
            `the parsing is finished with an opening quote at line ${this.info.lines}`,
          ], this.options, this.__infoField())
        );
        if(err !== undefined) return err;
      }else {
        // Skip last line if it has no characters
        if(this.state.wasQuoting === true || this.state.record.length !== 0 || this.state.field.length !== 0){
          this.info.bytes = this.state.bufBytesStart + pos;
          const errField = this.__onField();
          if(errField !== undefined) return errField;
          const errRecord = this.__onRecord();
          if(errRecord !== undefined) return errRecord;
        }else if(this.state.wasRowDelimiter === true){
          this.info.empty_lines++;
        }else if(this.state.commenting === true){
          this.info.comment_lines++;
        }
      }
    }else {
      this.state.bufBytesStart += pos;
      this.state.previousBuf = buf.slice(pos);
    }
    if(this.state.wasRowDelimiter === true){
      this.info.lines++;
      this.state.wasRowDelimiter = false;
    }
  }
  __onRecord(){
    const {columns, columns_duplicates_to_array, encoding, info, from, relax_column_count, relax_column_count_less, relax_column_count_more, raw, skip_lines_with_empty_values} = this.options;
    const {enabled, record} = this.state;
    if(enabled === false){
      return this.__resetRecord();
    }
    // Convert the first line into column names
    const recordLength = record.length;
    if(columns === true){
      if(skip_lines_with_empty_values === true && isRecordEmpty(record)){
        this.__resetRecord();
        return;
      }
      return this.__firstLineToColumns(record);
    }
    if(columns === false && this.info.records === 0){
      this.state.expectedRecordLength = recordLength;
    }
    if(recordLength !== this.state.expectedRecordLength){
      const err = columns === false ?
        // Todo: rename CSV_INCONSISTENT_RECORD_LENGTH to
        // CSV_RECORD_INCONSISTENT_FIELDS_LENGTH
        new CsvError('CSV_INCONSISTENT_RECORD_LENGTH', [
          'Invalid Record Length:',
          `expect ${this.state.expectedRecordLength},`,
          `got ${recordLength} on line ${this.info.lines}`,
        ], this.options, this.__infoField(), {
          record: record,
        })
        :
        // Todo: rename CSV_RECORD_DONT_MATCH_COLUMNS_LENGTH to
        // CSV_RECORD_INCONSISTENT_COLUMNS
        new CsvError('CSV_RECORD_DONT_MATCH_COLUMNS_LENGTH', [
          'Invalid Record Length:',
          `columns length is ${columns.length},`, // rename columns
          `got ${recordLength} on line ${this.info.lines}`,
        ], this.options, this.__infoField(), {
          record: record,
        });
      if(relax_column_count === true ||
        (relax_column_count_less === true && recordLength < this.state.expectedRecordLength) ||
        (relax_column_count_more === true && recordLength > this.state.expectedRecordLength)){
        this.info.invalid_field_length++;
        this.state.error = err;
      // Error is undefined with skip_lines_with_error
      }else {
        const finalErr = this.__error(err);
        if(finalErr) return finalErr;
      }
    }
    if(skip_lines_with_empty_values === true && isRecordEmpty(record)){
      this.__resetRecord();
      return;
    }
    if(this.state.recordHasError === true){
      this.__resetRecord();
      this.state.recordHasError = false;
      return;
    }
    this.info.records++;
    if(from === 1 || this.info.records >= from){
      // With columns, records are object
      if(columns !== false){
        const obj = {};
        // Transform record array to an object
        for(let i = 0, l = record.length; i < l; i++){
          if(columns[i] === undefined || columns[i].disabled) continue;
          // Turn duplicate columns into an array
          if (columns_duplicates_to_array === true && obj[columns[i].name] !== undefined) {
            if (Array.isArray(obj[columns[i].name])) {
              obj[columns[i].name] = obj[columns[i].name].concat(record[i]);
            } else {
              obj[columns[i].name] = [obj[columns[i].name], record[i]];
            }
          } else {
            obj[columns[i].name] = record[i];
          }
        }
        const {objname} = this.options;
        // Without objname (default)
        if(objname === undefined){
          if(raw === true || info === true){
            const err = this.__push(Object.assign(
              {record: obj},
              (raw === true ? {raw: this.state.rawBuffer.toString(encoding)}: {}),
              (info === true ? {info: this.__infoRecord()}: {})
            ));
            if(err){
              return err;
            }
          }else {
            const err = this.__push(obj);
            if(err){
              return err;
            }
          }
        // With objname (default)
        }else {
          if(raw === true || info === true){
            const err = this.__push(Object.assign(
              {record: [obj[objname], obj]},
              raw === true ? {raw: this.state.rawBuffer.toString(encoding)}: {},
              info === true ? {info: this.__infoRecord()}: {}
            ));
            if(err){
              return err;
            }
          }else {
            const err = this.__push([obj[objname], obj]);
            if(err){
              return err;
            }
          }
        }
      // Without columns, records are array
      }else {
        if(raw === true || info === true){
          const err = this.__push(Object.assign(
            {record: record},
            raw === true ? {raw: this.state.rawBuffer.toString(encoding)}: {},
            info === true ? {info: this.__infoRecord()}: {}
          ));
          if(err){
            return err;
          }
        }else {
          const err = this.__push(record);
          if(err){
            return err;
          }
        }
      }
    }
    this.__resetRecord();
  }
  __firstLineToColumns(record){
    const {firstLineToHeaders} = this.state;
    try{
      const headers = firstLineToHeaders === undefined ? record : firstLineToHeaders.call(null, record);
      if(!Array.isArray(headers)){
        return this.__error(
          new CsvError('CSV_INVALID_COLUMN_MAPPING', [
            'Invalid Column Mapping:',
            'expect an array from column function,',
            `got ${JSON.stringify(headers)}`
          ], this.options, this.__infoField(), {
            headers: headers,
          })
        );
      }
      const normalizedHeaders = normalizeColumnsArray(headers);
      this.state.expectedRecordLength = normalizedHeaders.length;
      this.options.columns = normalizedHeaders;
      this.__resetRecord();
      return;
    }catch(err){
      return err;
    }
  }
  __resetRecord(){
    if(this.options.raw === true){
      this.state.rawBuffer.reset();
    }
    this.state.error = undefined;
    this.state.record = [];
    this.state.record_length = 0;
  }
  __onField(){
    const {cast, encoding, rtrim, max_record_size} = this.options;
    const {enabled, wasQuoting} = this.state;
    // Short circuit for the from_line options
    if(enabled === false){
      return this.__resetField();
    }
    let field = this.state.field.toString(encoding);
    if(rtrim === true && wasQuoting === false){
      field = field.trimRight();
    }
    if(cast === true){
      const [err, f] = this.__cast(field);
      if(err !== undefined) return err;
      field = f;
    }
    this.state.record.push(field);
    // Increment record length if record size must not exceed a limit
    if(max_record_size !== 0 && typeof field === 'string'){
      this.state.record_length += field.length;
    }
    this.__resetField();
  }
  __resetField(){
    this.state.field.reset();
    this.state.wasQuoting = false;
  }
  __push(record){
    const {on_record} = this.options;
    if(on_record !== undefined){
      const info = this.__infoRecord();
      try{
        record = on_record.call(null, record, info);
      }catch(err){
        return err;
      }
      if(record === undefined || record === null){ return; }
    }
    this.push(record);
  }
  // Return a tuple with the error and the casted value
  __cast(field){
    const {columns, relax_column_count} = this.options;
    const isColumns = Array.isArray(columns);
    // Dont loose time calling cast
    // because the final record is an object
    // and this field can't be associated to a key present in columns
    if(isColumns === true && relax_column_count && this.options.columns.length <= this.state.record.length){
      return [undefined, undefined];
    }
    if(this.state.castField !== null){
      try{
        const info = this.__infoField();
        return [undefined, this.state.castField.call(null, field, info)];
      }catch(err){
        return [err];
      }
    }
    if(this.__isFloat(field)){
      return [undefined, parseFloat(field)];
    }else if(this.options.cast_date !== false){
      const info = this.__infoField();
      return [undefined, this.options.cast_date.call(null, field, info)];
    }
    return [undefined, field];
  }
  // Helper to test if a character is a space or a line delimiter
  __isCharTrimable(chr){
    return chr === space || chr === tab || chr === cr || chr === nl || chr === np;
  }
  // Keep it in case we implement the `cast_int` option
  // __isInt(value){
  //   // return Number.isInteger(parseInt(value))
  //   // return !isNaN( parseInt( obj ) );
  //   return /^(\-|\+)?[1-9][0-9]*$/.test(value)
  // }
  __isFloat(value){
    return (value - parseFloat(value) + 1) >= 0; // Borrowed from jquery
  }
  __compareBytes(sourceBuf, targetBuf, targetPos, firstByte){
    if(sourceBuf[0] !== firstByte) return 0;
    const sourceLength = sourceBuf.length;
    for(let i = 1; i < sourceLength; i++){
      if(sourceBuf[i] !== targetBuf[targetPos+i]) return 0;
    }
    return sourceLength;
  }
  __needMoreData(i, bufLen, end){
    if(end) return false;
    const {quote} = this.options;
    const {quoting, needMoreDataSize, recordDelimiterMaxLength} = this.state;
    const numOfCharLeft = bufLen - i - 1;
    const requiredLength = Math.max(
      needMoreDataSize,
      // Skip if the remaining buffer smaller than record delimiter
      recordDelimiterMaxLength,
      // Skip if the remaining buffer can be record delimiter following the closing quote
      // 1 is for quote.length
      quoting ? (quote.length + recordDelimiterMaxLength) : 0,
    );
    return numOfCharLeft < requiredLength;
  }
  __isDelimiter(buf, pos, chr){
    const {delimiter, ignore_last_delimiters} = this.options;
    if(ignore_last_delimiters === true && this.state.record.length === this.options.columns.length - 1){
      return 0;
    }else if(ignore_last_delimiters !== false && typeof ignore_last_delimiters === 'number' && this.state.record.length === ignore_last_delimiters - 1){
      return 0;
    }
    loop1: for(let i = 0; i < delimiter.length; i++){
      const del = delimiter[i];
      if(del[0] === chr){
        for(let j = 1; j < del.length; j++){
          if(del[j] !== buf[pos+j]) continue loop1;
        }
        return del.length;
      }
    }
    return 0;
  }
  __isRecordDelimiter(chr, buf, pos){
    const {record_delimiter} = this.options;
    const recordDelimiterLength = record_delimiter.length;
    loop1: for(let i = 0; i < recordDelimiterLength; i++){
      const rd = record_delimiter[i];
      const rdLength = rd.length;
      if(rd[0] !== chr){
        continue;
      }
      for(let j = 1; j < rdLength; j++){
        if(rd[j] !== buf[pos+j]){
          continue loop1;
        }
      }
      return rd.length;
    }
    return 0;
  }
  __isEscape(buf, pos, chr){
    const {escape} = this.options;
    if(escape === null) return false;
    const l = escape.length;
    if(escape[0] === chr){
      for(let i = 0; i < l; i++){
        if(escape[i] !== buf[pos+i]){
          return false;
        }
      }
      return true;
    }
    return false;
  }
  __isQuote(buf, pos){
    const {quote} = this.options;
    if(quote === null) return false;
    const l = quote.length;
    for(let i = 0; i < l; i++){
      if(quote[i] !== buf[pos+i]){
        return false;
      }
    }
    return true;
  }
  __autoDiscoverRecordDelimiter(buf, pos){
    const {encoding} = this.options;
    const chr = buf[pos];
    if(chr === cr){
      if(buf[pos+1] === nl){
        this.options.record_delimiter.push(Buffer.from('\r\n', encoding));
        this.state.recordDelimiterMaxLength = 2;
        return 2;
      }else {
        this.options.record_delimiter.push(Buffer.from('\r', encoding));
        this.state.recordDelimiterMaxLength = 1;
        return 1;
      }
    }else if(chr === nl){
      this.options.record_delimiter.push(Buffer.from('\n', encoding));
      this.state.recordDelimiterMaxLength = 1;
      return 1;
    }
    return 0;
  }
  __error(msg){
    const {encoding, raw, skip_lines_with_error} = this.options;
    const err = typeof msg === 'string' ? new Error(msg) : msg;
    if(skip_lines_with_error){
      this.state.recordHasError = true;
      this.emit('skip', err, raw ? this.state.rawBuffer.toString(encoding) : undefined);
      return undefined;
    }else {
      return err;
    }
  }
  __infoDataSet(){
    return {
      ...this.info,
      columns: this.options.columns
    };
  }
  __infoRecord(){
    const {columns, raw, encoding} = this.options;
    return {
      ...this.__infoDataSet(),
      error: this.state.error,
      header: columns === true,
      index: this.state.record.length,
      raw: raw ? this.state.rawBuffer.toString(encoding) : undefined
    };
  }
  __infoField(){
    const {columns} = this.options;
    const isColumns = Array.isArray(columns);
    return {
      ...this.__infoRecord(),
      column: isColumns === true ?
        (columns.length > this.state.record.length ?
          columns[this.state.record.length].name :
          null
        ) :
        this.state.record.length,
      quoting: this.state.wasQuoting,
    };
  }
}

const parse = function(){
  let data, options, callback;
  for(const i in arguments){
    const argument = arguments[i];
    const type = typeof argument;
    if(data === undefined && (typeof argument === 'string' || isBuffer(argument))){
      data = argument;
    }else if(options === undefined && isObject(argument)){
      options = argument;
    }else if(callback === undefined && type === 'function'){
      callback = argument;
    }else {
      throw new CsvError('CSV_INVALID_ARGUMENT', [
        'Invalid argument:',
        `got ${JSON.stringify(argument)} at index ${i}`
      ], options || {});
    }
  }
  const parser = new Parser(options);
  if(callback){
    const records = options === undefined || options.objname === undefined ? [] : {};
    parser.on('readable', function(){
      let record;
      while((record = this.read()) !== null){
        if(options === undefined || options.objname === undefined){
          records.push(record);
        }else {
          records[record[0]] = record[1];
        }
      }
    });
    parser.on('error', function(err){
      callback(err, undefined, parser.__infoDataSet());
    });
    parser.on('end', function(){
      callback(undefined, records, parser.__infoDataSet());
    });
  }
  if(data !== undefined){
    const writer = function(){
      parser.write(data);
      parser.end();
    };
    // Support Deno, Rollup doesnt provide a shim for setImmediate
    if(typeof setImmediate === 'function'){
      setImmediate(writer);
    }else {
      setTimeout(writer, 0);
    }
  }
  return parser;
};

exports.CsvError = CsvError;
exports.Parser = Parser;
exports.parse = parse;