dynatrace-cordova-outsystems-plugin/node_modules/asn1/lib/ber/writer.js

This plugin gives you the ability to use the Dynatrace instrumentation in your hybrid application (Cordova, Ionic, ..). It uses the Mobile Agent, the JavaScript Agent and the Javascript Bridge. The Mobile Agent will give you all device specific values con

// Copyright 2011 Mark Cavage <mcavage@gmail.com> All rights reserved.

var assert = require('assert');
var Buffer = require('safer-buffer').Buffer;
var ASN1 = require('./types');
var errors = require('./errors');


// --- Globals

var newInvalidAsn1Error = errors.newInvalidAsn1Error;

var DEFAULT_OPTS = {
  size: 1024,
  growthFactor: 8
};


// --- Helpers

function merge(from, to) {
  assert.ok(from);
  assert.equal(typeof (from), 'object');
  assert.ok(to);
  assert.equal(typeof (to), 'object');

  var keys = Object.getOwnPropertyNames(from);
  keys.forEach(function (key) {
    if (to[key])
      return;

    var value = Object.getOwnPropertyDescriptor(from, key);
    Object.defineProperty(to, key, value);
  });

  return to;
}



// --- API

function Writer(options) {
  options = merge(DEFAULT_OPTS, options || {});

  this._buf = Buffer.alloc(options.size || 1024);
  this._size = this._buf.length;
  this._offset = 0;
  this._options = options;

  // A list of offsets in the buffer where we need to insert
  // sequence tag/len pairs.
  this._seq = [];
}

Object.defineProperty(Writer.prototype, 'buffer', {
  get: function () {
    if (this._seq.length)
      throw newInvalidAsn1Error(this._seq.length + ' unended sequence(s)');

    return (this._buf.slice(0, this._offset));
  }
});

Writer.prototype.writeByte = function (b) {
  if (typeof (b) !== 'number')
    throw new TypeError('argument must be a Number');

  this._ensure(1);
  this._buf[this._offset++] = b;
};


Writer.prototype.writeInt = function (i, tag) {
  if (typeof (i) !== 'number')
    throw new TypeError('argument must be a Number');
  if (typeof (tag) !== 'number')
    tag = ASN1.Integer;

  var sz = 4;

  while ((((i & 0xff800000) === 0) || ((i & 0xff800000) === 0xff800000 >> 0)) &&
        (sz > 1)) {
    sz--;
    i <<= 8;
  }

  if (sz > 4)
    throw newInvalidAsn1Error('BER ints cannot be > 0xffffffff');

  this._ensure(2 + sz);
  this._buf[this._offset++] = tag;
  this._buf[this._offset++] = sz;

  while (sz-- > 0) {
    this._buf[this._offset++] = ((i & 0xff000000) >>> 24);
    i <<= 8;
  }

};


Writer.prototype.writeNull = function () {
  this.writeByte(ASN1.Null);
  this.writeByte(0x00);
};


Writer.prototype.writeEnumeration = function (i, tag) {
  if (typeof (i) !== 'number')
    throw new TypeError('argument must be a Number');
  if (typeof (tag) !== 'number')
    tag = ASN1.Enumeration;

  return this.writeInt(i, tag);
};


Writer.prototype.writeBoolean = function (b, tag) {
  if (typeof (b) !== 'boolean')
    throw new TypeError('argument must be a Boolean');
  if (typeof (tag) !== 'number')
    tag = ASN1.Boolean;

  this._ensure(3);
  this._buf[this._offset++] = tag;
  this._buf[this._offset++] = 0x01;
  this._buf[this._offset++] = b ? 0xff : 0x00;
};


Writer.prototype.writeString = function (s, tag) {
  if (typeof (s) !== 'string')
    throw new TypeError('argument must be a string (was: ' + typeof (s) + ')');
  if (typeof (tag) !== 'number')
    tag = ASN1.OctetString;

  var len = Buffer.byteLength(s);
  this.writeByte(tag);
  this.writeLength(len);
  if (len) {
    this._ensure(len);
    this._buf.write(s, this._offset);
    this._offset += len;
  }
};


Writer.prototype.writeBuffer = function (buf, tag) {
  if (typeof (tag) !== 'number')
    throw new TypeError('tag must be a number');
  if (!Buffer.isBuffer(buf))
    throw new TypeError('argument must be a buffer');

  this.writeByte(tag);
  this.writeLength(buf.length);
  this._ensure(buf.length);
  buf.copy(this._buf, this._offset, 0, buf.length);
  this._offset += buf.length;
};


Writer.prototype.writeStringArray = function (strings) {
  if ((!strings instanceof Array))
    throw new TypeError('argument must be an Array[String]');

  var self = this;
  strings.forEach(function (s) {
    self.writeString(s);
  });
};

// This is really to solve DER cases, but whatever for now
Writer.prototype.writeOID = function (s, tag) {
  if (typeof (s) !== 'string')
    throw new TypeError('argument must be a string');
  if (typeof (tag) !== 'number')
    tag = ASN1.OID;

  if (!/^([0-9]+\.){3,}[0-9]+$/.test(s))
    throw new Error('argument is not a valid OID string');

  function encodeOctet(bytes, octet) {
    if (octet < 128) {
        bytes.push(octet);
    } else if (octet < 16384) {
        bytes.push((octet >>> 7) | 0x80);
        bytes.push(octet & 0x7F);
    } else if (octet < 2097152) {
      bytes.push((octet >>> 14) | 0x80);
      bytes.push(((octet >>> 7) | 0x80) & 0xFF);
      bytes.push(octet & 0x7F);
    } else if (octet < 268435456) {
      bytes.push((octet >>> 21) | 0x80);
      bytes.push(((octet >>> 14) | 0x80) & 0xFF);
      bytes.push(((octet >>> 7) | 0x80) & 0xFF);
      bytes.push(octet & 0x7F);
    } else {
      bytes.push(((octet >>> 28) | 0x80) & 0xFF);
      bytes.push(((octet >>> 21) | 0x80) & 0xFF);
      bytes.push(((octet >>> 14) | 0x80) & 0xFF);
      bytes.push(((octet >>> 7) | 0x80) & 0xFF);
      bytes.push(octet & 0x7F);
    }
  }

  var tmp = s.split('.');
  var bytes = [];
  bytes.push(parseInt(tmp[0], 10) * 40 + parseInt(tmp[1], 10));
  tmp.slice(2).forEach(function (b) {
    encodeOctet(bytes, parseInt(b, 10));
  });

  var self = this;
  this._ensure(2 + bytes.length);
  this.writeByte(tag);
  this.writeLength(bytes.length);
  bytes.forEach(function (b) {
    self.writeByte(b);
  });
};


Writer.prototype.writeLength = function (len) {
  if (typeof (len) !== 'number')
    throw new TypeError('argument must be a Number');

  this._ensure(4);

  if (len <= 0x7f) {
    this._buf[this._offset++] = len;
  } else if (len <= 0xff) {
    this._buf[this._offset++] = 0x81;
    this._buf[this._offset++] = len;
  } else if (len <= 0xffff) {
    this._buf[this._offset++] = 0x82;
    this._buf[this._offset++] = len >> 8;
    this._buf[this._offset++] = len;
  } else if (len <= 0xffffff) {
    this._buf[this._offset++] = 0x83;
    this._buf[this._offset++] = len >> 16;
    this._buf[this._offset++] = len >> 8;
    this._buf[this._offset++] = len;
  } else {
    throw newInvalidAsn1Error('Length too long (> 4 bytes)');
  }
};

Writer.prototype.startSequence = function (tag) {
  if (typeof (tag) !== 'number')
    tag = ASN1.Sequence | ASN1.Constructor;

  this.writeByte(tag);
  this._seq.push(this._offset);
  this._ensure(3);
  this._offset += 3;
};


Writer.prototype.endSequence = function () {
  var seq = this._seq.pop();
  var start = seq + 3;
  var len = this._offset - start;

  if (len <= 0x7f) {
    this._shift(start, len, -2);
    this._buf[seq] = len;
  } else if (len <= 0xff) {
    this._shift(start, len, -1);
    this._buf[seq] = 0x81;
    this._buf[seq + 1] = len;
  } else if (len <= 0xffff) {
    this._buf[seq] = 0x82;
    this._buf[seq + 1] = len >> 8;
    this._buf[seq + 2] = len;
  } else if (len <= 0xffffff) {
    this._shift(start, len, 1);
    this._buf[seq] = 0x83;
    this._buf[seq + 1] = len >> 16;
    this._buf[seq + 2] = len >> 8;
    this._buf[seq + 3] = len;
  } else {
    throw newInvalidAsn1Error('Sequence too long');
  }
};


Writer.prototype._shift = function (start, len, shift) {
  assert.ok(start !== undefined);
  assert.ok(len !== undefined);
  assert.ok(shift);

  this._buf.copy(this._buf, start + shift, start, start + len);
  this._offset += shift;
};

Writer.prototype._ensure = function (len) {
  assert.ok(len);

  if (this._size - this._offset < len) {
    var sz = this._size * this._options.growthFactor;
    if (sz - this._offset < len)
      sz += len;

    var buf = Buffer.alloc(sz);

    this._buf.copy(buf, 0, 0, this._offset);
    this._buf = buf;
    this._size = sz;
  }
};



// --- Exported API

module.exports = Writer;