api, login, auth

2 files changed, 1082 insertions, 0 deletions

diff --git a/node_modules/browserify-zlib/src/binding.js b/node_modules/browserify-zlib/src/binding.js
new file mode 100644
index 0000000..14e419d
--- /dev/null
+++ b/node_modules/browserify-zlib/src/binding.js
@@ -0,0 +1,432 @@
+'use strict'
+/* eslint camelcase: "off" */
+
+var assert = require('assert')
+
+var Zstream = require('pako/lib/zlib/zstream')
+var zlib_deflate = require('pako/lib/zlib/deflate.js')
+var zlib_inflate = require('pako/lib/zlib/inflate.js')
+var constants = require('pako/lib/zlib/constants')
+
+for (var key in constants) {
+  exports[key] = constants[key]
+}
+
+// zlib modes
+exports.NONE = 0
+exports.DEFLATE = 1
+exports.INFLATE = 2
+exports.GZIP = 3
+exports.GUNZIP = 4
+exports.DEFLATERAW = 5
+exports.INFLATERAW = 6
+exports.UNZIP = 7
+
+var GZIP_HEADER_ID1 = 0x1f
+var GZIP_HEADER_ID2 = 0x8b
+
+/**
+ * Emulate Node's zlib C++ layer for use by the JS layer in index.js
+ */
+function Zlib (mode) {
+  if (typeof mode !== 'number' || mode < exports.DEFLATE || mode > exports.UNZIP) {
+    throw new TypeError('Bad argument')
+  }
+
+  this.dictionary = null
+  this.err = 0
+  this.flush = 0
+  this.init_done = false
+  this.level = 0
+  this.memLevel = 0
+  this.mode = mode
+  this.strategy = 0
+  this.windowBits = 0
+  this.write_in_progress = false
+  this.pending_close = false
+  this.gzip_id_bytes_read = 0
+}
+
+Zlib.prototype.close = function () {
+  if (this.write_in_progress) {
+    this.pending_close = true
+    return
+  }
+
+  this.pending_close = false
+
+  assert(this.init_done, 'close before init')
+  assert(this.mode <= exports.UNZIP)
+
+  if (this.mode === exports.DEFLATE || this.mode === exports.GZIP || this.mode === exports.DEFLATERAW) {
+    zlib_deflate.deflateEnd(this.strm)
+  } else if (this.mode === exports.INFLATE || this.mode === exports.GUNZIP ||
+      this.mode === exports.INFLATERAW || this.mode === exports.UNZIP) {
+    zlib_inflate.inflateEnd(this.strm)
+  }
+
+  this.mode = exports.NONE
+
+  this.dictionary = null
+}
+
+Zlib.prototype.write = function (flush, input, in_off, in_len, out, out_off, out_len) {
+  return this._write(true, flush, input, in_off, in_len, out, out_off, out_len)
+}
+
+Zlib.prototype.writeSync = function (flush, input, in_off, in_len, out, out_off, out_len) {
+  return this._write(false, flush, input, in_off, in_len, out, out_off, out_len)
+}
+
+Zlib.prototype._write = function (async, flush, input, in_off, in_len, out, out_off, out_len) {
+  assert.equal(arguments.length, 8)
+
+  assert(this.init_done, 'write before init')
+  assert(this.mode !== exports.NONE, 'already finalized')
+  assert.equal(false, this.write_in_progress, 'write already in progress')
+  assert.equal(false, this.pending_close, 'close is pending')
+
+  this.write_in_progress = true
+
+  assert.equal(false, flush === undefined, 'must provide flush value')
+
+  this.write_in_progress = true
+
+  if (flush !== exports.Z_NO_FLUSH &&
+    flush !== exports.Z_PARTIAL_FLUSH &&
+    flush !== exports.Z_SYNC_FLUSH &&
+    flush !== exports.Z_FULL_FLUSH &&
+    flush !== exports.Z_FINISH &&
+    flush !== exports.Z_BLOCK) {
+    throw new Error('Invalid flush value')
+  }
+
+  if (input == null) {
+    input = Buffer.alloc(0)
+    in_len = 0
+    in_off = 0
+  }
+
+  this.strm.avail_in = in_len
+  this.strm.input = input
+  this.strm.next_in = in_off
+  this.strm.avail_out = out_len
+  this.strm.output = out
+  this.strm.next_out = out_off
+  this.flush = flush
+
+  if (!async) {
+    // sync version
+    this._process()
+
+    if (this._checkError()) {
+      return this._afterSync()
+    }
+    return
+  }
+
+  // async version
+  var self = this
+  process.nextTick(function () {
+    self._process()
+    self._after()
+  })
+
+  return this
+}
+
+Zlib.prototype._afterSync = function () {
+  var avail_out = this.strm.avail_out
+  var avail_in = this.strm.avail_in
+
+  this.write_in_progress = false
+
+  return [avail_in, avail_out]
+}
+
+Zlib.prototype._process = function () {
+  var next_expected_header_byte = null
+
+  // If the avail_out is left at 0, then it means that it ran out
+  // of room.  If there was avail_out left over, then it means
+  // that all of the input was consumed.
+  switch (this.mode) {
+    case exports.DEFLATE:
+    case exports.GZIP:
+    case exports.DEFLATERAW:
+      this.err = zlib_deflate.deflate(this.strm, this.flush)
+      break
+    case exports.UNZIP:
+      if (this.strm.avail_in > 0) {
+        next_expected_header_byte = this.strm.next_in
+      }
+
+      switch (this.gzip_id_bytes_read) {
+        case 0:
+          if (next_expected_header_byte === null) {
+            break
+          }
+
+          if (this.strm.input[next_expected_header_byte] === GZIP_HEADER_ID1) {
+            this.gzip_id_bytes_read = 1
+            next_expected_header_byte++
+
+            if (this.strm.avail_in === 1) {
+              // The only available byte was already read.
+              break
+            }
+          } else {
+            this.mode = exports.INFLATE
+            break
+          }
+
+          // fallthrough
+        case 1:
+          if (next_expected_header_byte === null) {
+            break
+          }
+
+          if (this.strm.input[next_expected_header_byte] === GZIP_HEADER_ID2) {
+            this.gzip_id_bytes_read = 2
+            this.mode = exports.GUNZIP
+          } else {
+            // There is no actual difference between INFLATE and INFLATERAW
+            // (after initialization).
+            this.mode = exports.INFLATE
+          }
+
+          break
+        default:
+          throw new Error('invalid number of gzip magic number bytes read')
+      }
+
+      // fallthrough
+    case exports.INFLATE:
+    case exports.GUNZIP:
+    case exports.INFLATERAW:
+      this.err = zlib_inflate.inflate(this.strm, this.flush)
+
+      // If data was encoded with dictionary
+      if (this.err === exports.Z_NEED_DICT && this.dictionary) {
+        // Load it
+        this.err = zlib_inflate.inflateSetDictionary(this.strm, this.dictionary)
+        if (this.err === exports.Z_OK) {
+          // And try to decode again
+          this.err = zlib_inflate.inflate(this.strm, this.flush)
+        } else if (this.err === exports.Z_DATA_ERROR) {
+          // Both inflateSetDictionary() and inflate() return Z_DATA_ERROR.
+          // Make it possible for After() to tell a bad dictionary from bad
+          // input.
+          this.err = exports.Z_NEED_DICT
+        }
+      }
+      while (this.strm.avail_in > 0 &&
+             this.mode === exports.GUNZIP &&
+             this.err === exports.Z_STREAM_END &&
+             this.strm.next_in[0] !== 0x00) {
+        // Bytes remain in input buffer. Perhaps this is another compressed
+        // member in the same archive, or just trailing garbage.
+        // Trailing zero bytes are okay, though, since they are frequently
+        // used for padding.
+
+        this.reset()
+        this.err = zlib_inflate.inflate(this.strm, this.flush)
+      }
+      break
+    default:
+      throw new Error('Unknown mode ' + this.mode)
+  }
+}
+
+Zlib.prototype._checkError = function () {
+  // Acceptable error states depend on the type of zlib stream.
+  switch (this.err) {
+    case exports.Z_OK:
+    case exports.Z_BUF_ERROR:
+      if (this.strm.avail_out !== 0 && this.flush === exports.Z_FINISH) {
+        this._error('unexpected end of file')
+        return false
+      }
+      break
+    case exports.Z_STREAM_END:
+      // normal statuses, not fatal
+      break
+    case exports.Z_NEED_DICT:
+      if (this.dictionary == null) {
+        this._error('Missing dictionary')
+      } else {
+        this._error('Bad dictionary')
+      }
+      return false
+    default:
+      // something else.
+      this._error('Zlib error')
+      return false
+  }
+
+  return true
+}
+
+Zlib.prototype._after = function () {
+  if (!this._checkError()) {
+    return
+  }
+
+  var avail_out = this.strm.avail_out
+  var avail_in = this.strm.avail_in
+
+  this.write_in_progress = false
+
+  // call the write() cb
+  this.callback(avail_in, avail_out)
+
+  if (this.pending_close) {
+    this.close()
+  }
+}
+
+Zlib.prototype._error = function (message) {
+  if (this.strm.msg) {
+    message = this.strm.msg
+  }
+  this.onerror(message, this.err)
+
+  // no hope of rescue.
+  this.write_in_progress = false
+  if (this.pending_close) {
+    this.close()
+  }
+}
+
+Zlib.prototype.init = function (windowBits, level, memLevel, strategy, dictionary) {
+  assert(arguments.length === 4 || arguments.length === 5, 'init(windowBits, level, memLevel, strategy, [dictionary])')
+
+  assert(windowBits >= 8 && windowBits <= 15, 'invalid windowBits')
+  assert(level >= -1 && level <= 9, 'invalid compression level')
+
+  assert(memLevel >= 1 && memLevel <= 9, 'invalid memlevel')
+
+  assert(strategy === exports.Z_FILTERED ||
+         strategy === exports.Z_HUFFMAN_ONLY ||
+         strategy === exports.Z_RLE ||
+         strategy === exports.Z_FIXED ||
+         strategy === exports.Z_DEFAULT_STRATEGY, 'invalid strategy')
+
+  this._init(level, windowBits, memLevel, strategy, dictionary)
+  this._setDictionary()
+}
+
+Zlib.prototype.params = function () {
+  throw new Error('deflateParams Not supported')
+}
+
+Zlib.prototype.reset = function () {
+  this._reset()
+  this._setDictionary()
+}
+
+Zlib.prototype._init = function (level, windowBits, memLevel, strategy, dictionary) {
+  this.level = level
+  this.windowBits = windowBits
+  this.memLevel = memLevel
+  this.strategy = strategy
+
+  this.flush = exports.Z_NO_FLUSH
+
+  this.err = exports.Z_OK
+
+  if (this.mode === exports.GZIP || this.mode === exports.GUNZIP) {
+    this.windowBits += 16
+  }
+
+  if (this.mode === exports.UNZIP) {
+    this.windowBits += 32
+  }
+
+  if (this.mode === exports.DEFLATERAW || this.mode === exports.INFLATERAW) {
+    this.windowBits = -1 * this.windowBits
+  }
+
+  this.strm = new Zstream()
+
+  switch (this.mode) {
+    case exports.DEFLATE:
+    case exports.GZIP:
+    case exports.DEFLATERAW:
+      this.err = zlib_deflate.deflateInit2(
+        this.strm,
+        this.level,
+        exports.Z_DEFLATED,
+        this.windowBits,
+        this.memLevel,
+        this.strategy
+      )
+      break
+    case exports.INFLATE:
+    case exports.GUNZIP:
+    case exports.INFLATERAW:
+    case exports.UNZIP:
+      this.err = zlib_inflate.inflateInit2(
+        this.strm,
+        this.windowBits
+      )
+      break
+    default:
+      throw new Error('Unknown mode ' + this.mode)
+  }
+
+  if (this.err !== exports.Z_OK) {
+    this._error('Init error')
+  }
+
+  this.dictionary = dictionary
+
+  this.write_in_progress = false
+  this.init_done = true
+}
+
+Zlib.prototype._setDictionary = function () {
+  if (this.dictionary == null) {
+    return
+  }
+
+  this.err = exports.Z_OK
+
+  switch (this.mode) {
+    case exports.DEFLATE:
+    case exports.DEFLATERAW:
+      this.err = zlib_deflate.deflateSetDictionary(this.strm, this.dictionary)
+      break
+    default:
+      break
+  }
+
+  if (this.err !== exports.Z_OK) {
+    this._error('Failed to set dictionary')
+  }
+}
+
+Zlib.prototype._reset = function () {
+  this.err = exports.Z_OK
+
+  switch (this.mode) {
+    case exports.DEFLATE:
+    case exports.DEFLATERAW:
+    case exports.GZIP:
+      this.err = zlib_deflate.deflateReset(this.strm)
+      break
+    case exports.INFLATE:
+    case exports.INFLATERAW:
+    case exports.GUNZIP:
+      this.err = zlib_inflate.inflateReset(this.strm)
+      break
+    default:
+      break
+  }
+
+  if (this.err !== exports.Z_OK) {
+    this._error('Failed to reset stream')
+  }
+}
+
+exports.Zlib = Zlib
diff --git a/node_modules/browserify-zlib/src/index.js b/node_modules/browserify-zlib/src/index.js
new file mode 100644
index 0000000..12f1ad0
--- /dev/null
+++ b/node_modules/browserify-zlib/src/index.js
@@ -0,0 +1,650 @@
+'use strict';
+
+const Buffer = require('buffer').Buffer;
+const Transform = require('stream').Transform;
+const binding = require('./binding');
+const util = require('util');
+const assert = require('assert').ok;
+const kMaxLength = require('buffer').kMaxLength;
+const kRangeErrorMessage = 'Cannot create final Buffer. It would be larger ' +
+                           'than 0x' + kMaxLength.toString(16) + ' bytes';
+
+// zlib doesn't provide these, so kludge them in following the same
+// const naming scheme zlib uses.
+binding.Z_MIN_WINDOWBITS = 8;
+binding.Z_MAX_WINDOWBITS = 15;
+binding.Z_DEFAULT_WINDOWBITS = 15;
+
+// fewer than 64 bytes per chunk is stupid.
+// technically it could work with as few as 8, but even 64 bytes
+// is absurdly low.  Usually a MB or more is best.
+binding.Z_MIN_CHUNK = 64;
+binding.Z_MAX_CHUNK = Infinity;
+binding.Z_DEFAULT_CHUNK = (16 * 1024);
+
+binding.Z_MIN_MEMLEVEL = 1;
+binding.Z_MAX_MEMLEVEL = 9;
+binding.Z_DEFAULT_MEMLEVEL = 8;
+
+binding.Z_MIN_LEVEL = -1;
+binding.Z_MAX_LEVEL = 9;
+binding.Z_DEFAULT_LEVEL = binding.Z_DEFAULT_COMPRESSION;
+
+// expose all the zlib constants
+const bkeys = Object.keys(binding);
+for (var bk = 0; bk < bkeys.length; bk++) {
+  var bkey = bkeys[bk];
+  if (bkey.match(/^Z/)) {
+    Object.defineProperty(exports, bkey, {
+      enumerable: true, value: binding[bkey], writable: false
+    });
+  }
+}
+
+// translation table for return codes.
+const codes = {
+  Z_OK: binding.Z_OK,
+  Z_STREAM_END: binding.Z_STREAM_END,
+  Z_NEED_DICT: binding.Z_NEED_DICT,
+  Z_ERRNO: binding.Z_ERRNO,
+  Z_STREAM_ERROR: binding.Z_STREAM_ERROR,
+  Z_DATA_ERROR: binding.Z_DATA_ERROR,
+  Z_MEM_ERROR: binding.Z_MEM_ERROR,
+  Z_BUF_ERROR: binding.Z_BUF_ERROR,
+  Z_VERSION_ERROR: binding.Z_VERSION_ERROR
+};
+
+const ckeys = Object.keys(codes);
+for (var ck = 0; ck < ckeys.length; ck++) {
+  var ckey = ckeys[ck];
+  codes[codes[ckey]] = ckey;
+}
+
+Object.defineProperty(exports, 'codes', {
+  enumerable: true, value: Object.freeze(codes), writable: false
+});
+
+exports.Deflate = Deflate;
+exports.Inflate = Inflate;
+exports.Gzip = Gzip;
+exports.Gunzip = Gunzip;
+exports.DeflateRaw = DeflateRaw;
+exports.InflateRaw = InflateRaw;
+exports.Unzip = Unzip;
+
+exports.createDeflate = function(o) {
+  return new Deflate(o);
+};
+
+exports.createInflate = function(o) {
+  return new Inflate(o);
+};
+
+exports.createDeflateRaw = function(o) {
+  return new DeflateRaw(o);
+};
+
+exports.createInflateRaw = function(o) {
+  return new InflateRaw(o);
+};
+
+exports.createGzip = function(o) {
+  return new Gzip(o);
+};
+
+exports.createGunzip = function(o) {
+  return new Gunzip(o);
+};
+
+exports.createUnzip = function(o) {
+  return new Unzip(o);
+};
+
+
+// Convenience methods.
+// compress/decompress a string or buffer in one step.
+exports.deflate = function(buffer, opts, callback) {
+  if (typeof opts === 'function') {
+    callback = opts;
+    opts = {};
+  }
+  return zlibBuffer(new Deflate(opts), buffer, callback);
+};
+
+exports.deflateSync = function(buffer, opts) {
+  return zlibBufferSync(new Deflate(opts), buffer);
+};
+
+exports.gzip = function(buffer, opts, callback) {
+  if (typeof opts === 'function') {
+    callback = opts;
+    opts = {};
+  }
+  return zlibBuffer(new Gzip(opts), buffer, callback);
+};
+
+exports.gzipSync = function(buffer, opts) {
+  return zlibBufferSync(new Gzip(opts), buffer);
+};
+
+exports.deflateRaw = function(buffer, opts, callback) {
+  if (typeof opts === 'function') {
+    callback = opts;
+    opts = {};
+  }
+  return zlibBuffer(new DeflateRaw(opts), buffer, callback);
+};
+
+exports.deflateRawSync = function(buffer, opts) {
+  return zlibBufferSync(new DeflateRaw(opts), buffer);
+};
+
+exports.unzip = function(buffer, opts, callback) {
+  if (typeof opts === 'function') {
+    callback = opts;
+    opts = {};
+  }
+  return zlibBuffer(new Unzip(opts), buffer, callback);
+};
+
+exports.unzipSync = function(buffer, opts) {
+  return zlibBufferSync(new Unzip(opts), buffer);
+};
+
+exports.inflate = function(buffer, opts, callback) {
+  if (typeof opts === 'function') {
+    callback = opts;
+    opts = {};
+  }
+  return zlibBuffer(new Inflate(opts), buffer, callback);
+};
+
+exports.inflateSync = function(buffer, opts) {
+  return zlibBufferSync(new Inflate(opts), buffer);
+};
+
+exports.gunzip = function(buffer, opts, callback) {
+  if (typeof opts === 'function') {
+    callback = opts;
+    opts = {};
+  }
+  return zlibBuffer(new Gunzip(opts), buffer, callback);
+};
+
+exports.gunzipSync = function(buffer, opts) {
+  return zlibBufferSync(new Gunzip(opts), buffer);
+};
+
+exports.inflateRaw = function(buffer, opts, callback) {
+  if (typeof opts === 'function') {
+    callback = opts;
+    opts = {};
+  }
+  return zlibBuffer(new InflateRaw(opts), buffer, callback);
+};
+
+exports.inflateRawSync = function(buffer, opts) {
+  return zlibBufferSync(new InflateRaw(opts), buffer);
+};
+
+function zlibBuffer(engine, buffer, callback) {
+  var buffers = [];
+  var nread = 0;
+
+  engine.on('error', onError);
+  engine.on('end', onEnd);
+
+  engine.end(buffer);
+  flow();
+
+  function flow() {
+    var chunk;
+    while (null !== (chunk = engine.read())) {
+      buffers.push(chunk);
+      nread += chunk.length;
+    }
+    engine.once('readable', flow);
+  }
+
+  function onError(err) {
+    engine.removeListener('end', onEnd);
+    engine.removeListener('readable', flow);
+    callback(err);
+  }
+
+  function onEnd() {
+    var buf;
+    var err = null;
+
+    if (nread >= kMaxLength) {
+      err = new RangeError(kRangeErrorMessage);
+    } else {
+      buf = Buffer.concat(buffers, nread);
+    }
+
+    buffers = [];
+    engine.close();
+    callback(err, buf);
+  }
+}
+
+function zlibBufferSync(engine, buffer) {
+  if (typeof buffer === 'string')
+    buffer = Buffer.from(buffer);
+
+  if (!Buffer.isBuffer(buffer))
+    throw new TypeError('Not a string or buffer');
+
+  var flushFlag = engine._finishFlushFlag;
+
+  return engine._processChunk(buffer, flushFlag);
+}
+
+// generic zlib
+// minimal 2-byte header
+function Deflate(opts) {
+  if (!(this instanceof Deflate)) return new Deflate(opts);
+  Zlib.call(this, opts, binding.DEFLATE);
+}
+
+function Inflate(opts) {
+  if (!(this instanceof Inflate)) return new Inflate(opts);
+  Zlib.call(this, opts, binding.INFLATE);
+}
+
+
+// gzip - bigger header, same deflate compression
+function Gzip(opts) {
+  if (!(this instanceof Gzip)) return new Gzip(opts);
+  Zlib.call(this, opts, binding.GZIP);
+}
+
+function Gunzip(opts) {
+  if (!(this instanceof Gunzip)) return new Gunzip(opts);
+  Zlib.call(this, opts, binding.GUNZIP);
+}
+
+
+// raw - no header
+function DeflateRaw(opts) {
+  if (!(this instanceof DeflateRaw)) return new DeflateRaw(opts);
+  Zlib.call(this, opts, binding.DEFLATERAW);
+}
+
+function InflateRaw(opts) {
+  if (!(this instanceof InflateRaw)) return new InflateRaw(opts);
+  Zlib.call(this, opts, binding.INFLATERAW);
+}
+
+
+// auto-detect header.
+function Unzip(opts) {
+  if (!(this instanceof Unzip)) return new Unzip(opts);
+  Zlib.call(this, opts, binding.UNZIP);
+}
+
+function isValidFlushFlag(flag) {
+  return flag === binding.Z_NO_FLUSH ||
+         flag === binding.Z_PARTIAL_FLUSH ||
+         flag === binding.Z_SYNC_FLUSH ||
+         flag === binding.Z_FULL_FLUSH ||
+         flag === binding.Z_FINISH ||
+         flag === binding.Z_BLOCK;
+}
+
+// the Zlib class they all inherit from
+// This thing manages the queue of requests, and returns
+// true or false if there is anything in the queue when
+// you call the .write() method.
+
+function Zlib(opts, mode) {
+  this._opts = opts = opts || {};
+  this._chunkSize = opts.chunkSize || exports.Z_DEFAULT_CHUNK;
+
+  Transform.call(this, opts);
+
+  if (opts.flush && !isValidFlushFlag(opts.flush)) {
+    throw new Error('Invalid flush flag: ' + opts.flush);
+  }
+  if (opts.finishFlush && !isValidFlushFlag(opts.finishFlush)) {
+    throw new Error('Invalid flush flag: ' + opts.finishFlush);
+  }
+
+  this._flushFlag = opts.flush || binding.Z_NO_FLUSH;
+  this._finishFlushFlag = typeof opts.finishFlush !== 'undefined' ?
+    opts.finishFlush : binding.Z_FINISH;
+
+  if (opts.chunkSize) {
+    if (opts.chunkSize < exports.Z_MIN_CHUNK ||
+        opts.chunkSize > exports.Z_MAX_CHUNK) {
+      throw new Error('Invalid chunk size: ' + opts.chunkSize);
+    }
+  }
+
+  if (opts.windowBits) {
+    if (opts.windowBits < exports.Z_MIN_WINDOWBITS ||
+        opts.windowBits > exports.Z_MAX_WINDOWBITS) {
+      throw new Error('Invalid windowBits: ' + opts.windowBits);
+    }
+  }
+
+  if (opts.level) {
+    if (opts.level < exports.Z_MIN_LEVEL ||
+        opts.level > exports.Z_MAX_LEVEL) {
+      throw new Error('Invalid compression level: ' + opts.level);
+    }
+  }
+
+  if (opts.memLevel) {
+    if (opts.memLevel < exports.Z_MIN_MEMLEVEL ||
+        opts.memLevel > exports.Z_MAX_MEMLEVEL) {
+      throw new Error('Invalid memLevel: ' + opts.memLevel);
+    }
+  }
+
+  if (opts.strategy) {
+    if (opts.strategy != exports.Z_FILTERED &&
+        opts.strategy != exports.Z_HUFFMAN_ONLY &&
+        opts.strategy != exports.Z_RLE &&
+        opts.strategy != exports.Z_FIXED &&
+        opts.strategy != exports.Z_DEFAULT_STRATEGY) {
+      throw new Error('Invalid strategy: ' + opts.strategy);
+    }
+  }
+
+  if (opts.dictionary) {
+    if (!Buffer.isBuffer(opts.dictionary)) {
+      throw new Error('Invalid dictionary: it should be a Buffer instance');
+    }
+  }
+
+  this._handle = new binding.Zlib(mode);
+
+  var self = this;
+  this._hadError = false;
+  this._handle.onerror = function(message, errno) {
+    // there is no way to cleanly recover.
+    // continuing only obscures problems.
+    _close(self);
+    self._hadError = true;
+
+    var error = new Error(message);
+    error.errno = errno;
+    error.code = exports.codes[errno];
+    self.emit('error', error);
+  };
+
+  var level = exports.Z_DEFAULT_COMPRESSION;
+  if (typeof opts.level === 'number') level = opts.level;
+
+  var strategy = exports.Z_DEFAULT_STRATEGY;
+  if (typeof opts.strategy === 'number') strategy = opts.strategy;
+
+  this._handle.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS,
+                    level,
+                    opts.memLevel || exports.Z_DEFAULT_MEMLEVEL,
+                    strategy,
+                    opts.dictionary);
+
+  this._buffer = Buffer.allocUnsafe(this._chunkSize);
+  this._offset = 0;
+  this._level = level;
+  this._strategy = strategy;
+
+  this.once('end', this.close);
+
+  Object.defineProperty(this, '_closed', {
+    get: () => { return !this._handle; },
+    configurable: true,
+    enumerable: true
+  });
+}
+
+util.inherits(Zlib, Transform);
+
+Zlib.prototype.params = function(level, strategy, callback) {
+  if (level < exports.Z_MIN_LEVEL ||
+      level > exports.Z_MAX_LEVEL) {
+    throw new RangeError('Invalid compression level: ' + level);
+  }
+  if (strategy != exports.Z_FILTERED &&
+      strategy != exports.Z_HUFFMAN_ONLY &&
+      strategy != exports.Z_RLE &&
+      strategy != exports.Z_FIXED &&
+      strategy != exports.Z_DEFAULT_STRATEGY) {
+    throw new TypeError('Invalid strategy: ' + strategy);
+  }
+
+  if (this._level !== level || this._strategy !== strategy) {
+    var self = this;
+    this.flush(binding.Z_SYNC_FLUSH, function() {
+      assert(self._handle, 'zlib binding closed');
+      self._handle.params(level, strategy);
+      if (!self._hadError) {
+        self._level = level;
+        self._strategy = strategy;
+        if (callback) callback();
+      }
+    });
+  } else {
+    process.nextTick(callback);
+  }
+};
+
+Zlib.prototype.reset = function() {
+  assert(this._handle, 'zlib binding closed');
+  return this._handle.reset();
+};
+
+// This is the _flush function called by the transform class,
+// internally, when the last chunk has been written.
+Zlib.prototype._flush = function(callback) {
+  this._transform(Buffer.alloc(0), '', callback);
+};
+
+Zlib.prototype.flush = function(kind, callback) {
+  var ws = this._writableState;
+
+  if (typeof kind === 'function' || (kind === undefined && !callback)) {
+    callback = kind;
+    kind = binding.Z_FULL_FLUSH;
+  }
+
+  if (ws.ended) {
+    if (callback)
+      process.nextTick(callback);
+  } else if (ws.ending) {
+    if (callback)
+      this.once('end', callback);
+  } else if (ws.needDrain) {
+    if (callback) {
+      this.once('drain', () => this.flush(kind, callback));
+    }
+  } else {
+    this._flushFlag = kind;
+    this.write(Buffer.alloc(0), '', callback);
+  }
+};
+
+Zlib.prototype.close = function(callback) {
+  _close(this, callback);
+  process.nextTick(emitCloseNT, this);
+};
+
+function _close(engine, callback) {
+  if (callback)
+    process.nextTick(callback);
+
+  // Caller may invoke .close after a zlib error (which will null _handle).
+  if (!engine._handle)
+    return;
+
+  engine._handle.close();
+  engine._handle = null;
+}
+
+function emitCloseNT(self) {
+  self.emit('close');
+}
+
+Zlib.prototype._transform = function(chunk, encoding, cb) {
+  var flushFlag;
+  var ws = this._writableState;
+  var ending = ws.ending || ws.ended;
+  var last = ending && (!chunk || ws.length === chunk.length);
+
+  if (chunk !== null && !Buffer.isBuffer(chunk))
+    return cb(new Error('invalid input'));
+
+  if (!this._handle)
+    return cb(new Error('zlib binding closed'));
+
+  // If it's the last chunk, or a final flush, we use the Z_FINISH flush flag
+  // (or whatever flag was provided using opts.finishFlush).
+  // If it's explicitly flushing at some other time, then we use
+  // Z_FULL_FLUSH. Otherwise, use Z_NO_FLUSH for maximum compression
+  // goodness.
+  if (last)
+    flushFlag = this._finishFlushFlag;
+  else {
+    flushFlag = this._flushFlag;
+    // once we've flushed the last of the queue, stop flushing and
+    // go back to the normal behavior.
+    if (chunk.length >= ws.length) {
+      this._flushFlag = this._opts.flush || binding.Z_NO_FLUSH;
+    }
+  }
+
+  this._processChunk(chunk, flushFlag, cb);
+};
+
+Zlib.prototype._processChunk = function(chunk, flushFlag, cb) {
+  var availInBefore = chunk && chunk.length;
+  var availOutBefore = this._chunkSize - this._offset;
+  var inOff = 0;
+
+  var self = this;
+
+  var async = typeof cb === 'function';
+
+  if (!async) {
+    var buffers = [];
+    var nread = 0;
+
+    var error;
+    this.on('error', function(er) {
+      error = er;
+    });
+
+    assert(this._handle, 'zlib binding closed');
+    do {
+      var res = this._handle.writeSync(flushFlag,
+                                       chunk, // in
+                                       inOff, // in_off
+                                       availInBefore, // in_len
+                                       this._buffer, // out
+                                       this._offset, //out_off
+                                       availOutBefore); // out_len
+    } while (!this._hadError && callback(res[0], res[1]));
+
+    if (this._hadError) {
+      throw error;
+    }
+
+    if (nread >= kMaxLength) {
+      _close(this);
+      throw new RangeError(kRangeErrorMessage);
+    }
+
+    var buf = Buffer.concat(buffers, nread);
+    _close(this);
+
+    return buf;
+  }
+
+  assert(this._handle, 'zlib binding closed');
+  var req = this._handle.write(flushFlag,
+                               chunk, // in
+                               inOff, // in_off
+                               availInBefore, // in_len
+                               this._buffer, // out
+                               this._offset, //out_off
+                               availOutBefore); // out_len
+
+  req.buffer = chunk;
+  req.callback = callback;
+
+  function callback(availInAfter, availOutAfter) {
+    // When the callback is used in an async write, the callback's
+    // context is the `req` object that was created. The req object
+    // is === this._handle, and that's why it's important to null
+    // out the values after they are done being used. `this._handle`
+    // can stay in memory longer than the callback and buffer are needed.
+    if (this) {
+      this.buffer = null;
+      this.callback = null;
+    }
+
+    if (self._hadError)
+      return;
+
+    var have = availOutBefore - availOutAfter;
+    assert(have >= 0, 'have should not go down');
+
+    if (have > 0) {
+      var out = self._buffer.slice(self._offset, self._offset + have);
+      self._offset += have;
+      // serve some output to the consumer.
+      if (async) {
+        self.push(out);
+      } else {
+        buffers.push(out);
+        nread += out.length;
+      }
+    }
+
+    // exhausted the output buffer, or used all the input create a new one.
+    if (availOutAfter === 0 || self._offset >= self._chunkSize) {
+      availOutBefore = self._chunkSize;
+      self._offset = 0;
+      self._buffer = Buffer.allocUnsafe(self._chunkSize);
+    }
+
+    if (availOutAfter === 0) {
+      // Not actually done.  Need to reprocess.
+      // Also, update the availInBefore to the availInAfter value,
+      // so that if we have to hit it a third (fourth, etc.) time,
+      // it'll have the correct byte counts.
+      inOff += (availInBefore - availInAfter);
+      availInBefore = availInAfter;
+
+      if (!async)
+        return true;
+
+      var newReq = self._handle.write(flushFlag,
+                                      chunk,
+                                      inOff,
+                                      availInBefore,
+                                      self._buffer,
+                                      self._offset,
+                                      self._chunkSize);
+      newReq.callback = callback; // this same function
+      newReq.buffer = chunk;
+      return;
+    }
+
+    if (!async)
+      return false;
+
+    // finished with the chunk.
+    cb();
+  }
+};
+
+util.inherits(Deflate, Zlib);
+util.inherits(Inflate, Zlib);
+util.inherits(Gzip, Zlib);
+util.inherits(Gunzip, Zlib);
+util.inherits(DeflateRaw, Zlib);
+util.inherits(InflateRaw, Zlib);
+util.inherits(Unzip, Zlib);