Current Dev State

static/js/ketcher2/node_modules/browserify-zlib/src/binding.js

@@ -0,0 +1,236 @@
+var msg = require('pako/lib/zlib/messages');
+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;
+
+/**
+ * Emulate Node's zlib C++ layer for use by the JS layer in index.js
+ */
+function Zlib(mode) {
+  if (mode < exports.DEFLATE || mode > exports.UNZIP)
+    throw new TypeError("Bad argument");
+    
+  this.mode = mode;
+  this.init_done = false;
+  this.write_in_progress = false;
+  this.pending_close = false;
+  this.windowBits = 0;
+  this.level = 0;
+  this.memLevel = 0;
+  this.strategy = 0;
+  this.dictionary = null;
+}
+
+Zlib.prototype.init = function(windowBits, level, memLevel, strategy, dictionary) {
+  this.windowBits = windowBits;
+  this.level = level;
+  this.memLevel = memLevel;
+  this.strategy = strategy;
+  // dictionary not supported.
+  
+  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 = -this.windowBits;
+    
+  this.strm = new zstream();
+  
+  switch (this.mode) {
+    case exports.DEFLATE:
+    case exports.GZIP:
+    case exports.DEFLATERAW:
+      var status = 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:
+      var status  = zlib_inflate.inflateInit2(
+        this.strm,
+        this.windowBits
+      );
+      break;
+    default:
+      throw new Error("Unknown mode " + this.mode);
+  }
+  
+  if (status !== exports.Z_OK) {
+    this._error(status);
+    return;
+  }
+  
+  this.write_in_progress = false;
+  this.init_done = true;
+};
+
+Zlib.prototype.params = function() {
+  throw new Error("deflateParams Not supported");
+};
+
+Zlib.prototype._writeCheck = function() {
+  if (!this.init_done)
+    throw new Error("write before init");
+    
+  if (this.mode === exports.NONE)
+    throw new Error("already finalized");
+    
+  if (this.write_in_progress)
+    throw new Error("write already in progress");
+    
+  if (this.pending_close)
+    throw new Error("close is pending");
+};
+
+Zlib.prototype.write = function(flush, input, in_off, in_len, out, out_off, out_len) {    
+  this._writeCheck();
+  this.write_in_progress = true;
+  
+  var self = this;
+  process.nextTick(function() {
+    self.write_in_progress = false;
+    var res = self._write(flush, input, in_off, in_len, out, out_off, out_len);
+    self.callback(res[0], res[1]);
+    
+    if (self.pending_close)
+      self.close();
+  });
+  
+  return this;
+};
+
+// set method for Node buffers, used by pako
+function bufferSet(data, offset) {
+  for (var i = 0; i < data.length; i++) {
+    this[offset + i] = data[i];
+  }
+}
+
+Zlib.prototype.writeSync = function(flush, input, in_off, in_len, out, out_off, out_len) {
+  this._writeCheck();
+  return this._write(flush, input, in_off, in_len, out, out_off, out_len);
+};
+
+Zlib.prototype._write = function(flush, input, in_off, in_len, out, out_off, out_len) {
+  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 = new Buffer(0);
+    in_len = 0;
+    in_off = 0;
+  }
+  
+  if (out._set)
+    out.set = out._set;
+  else
+    out.set = bufferSet;
+  
+  var strm = this.strm;
+  strm.avail_in = in_len;
+  strm.input = input;
+  strm.next_in = in_off;
+  strm.avail_out = out_len;
+  strm.output = out;
+  strm.next_out = out_off;
+  
+  switch (this.mode) {
+    case exports.DEFLATE:
+    case exports.GZIP:
+    case exports.DEFLATERAW:
+      var status = zlib_deflate.deflate(strm, flush);
+      break;
+    case exports.UNZIP:
+    case exports.INFLATE:
+    case exports.GUNZIP:
+    case exports.INFLATERAW:
+      var status = zlib_inflate.inflate(strm, flush);
+      break;
+    default:
+      throw new Error("Unknown mode " + this.mode);
+  }
+  
+  if (status !== exports.Z_STREAM_END && status !== exports.Z_OK) {
+    this._error(status);
+  }
+  
+  this.write_in_progress = false;
+  return [strm.avail_in, strm.avail_out];
+};
+
+Zlib.prototype.close = function() {
+  if (this.write_in_progress) {
+    this.pending_close = true;
+    return;
+  }
+  
+  this.pending_close = false;
+  
+  if (this.mode === exports.DEFLATE || this.mode === exports.GZIP || this.mode === exports.DEFLATERAW) {
+    zlib_deflate.deflateEnd(this.strm);
+  } else {
+    zlib_inflate.inflateEnd(this.strm);
+  }
+  
+  this.mode = exports.NONE;
+};
+
+Zlib.prototype.reset = function() {
+  switch (this.mode) {
+    case exports.DEFLATE:
+    case exports.DEFLATERAW:
+      var status = zlib_deflate.deflateReset(this.strm);
+      break;
+    case exports.INFLATE:
+    case exports.INFLATERAW:
+      var status = zlib_inflate.inflateReset(this.strm);
+      break;
+  }
+  
+  if (status !== exports.Z_OK) {
+    this._error(status);
+  }
+};
+
+Zlib.prototype._error = function(status) {
+  this.onerror(msg[status] + ': ' + this.strm.msg, status);
+  
+  this.write_in_progress = false;
+  if (this.pending_close)
+    this.close();
+};
+
+exports.Zlib = Zlib;

static/js/ketcher2/node_modules/browserify-zlib/src/index.js

@@ -0,0 +1,610 @@
+// Copyright Joyent, Inc. and other Node contributors.
+//
+// Permission is hereby granted, free of charge, to any person obtaining a
+// copy of this software and associated documentation files (the
+// "Software"), to deal in the Software without restriction, including
+// without limitation the rights to use, copy, modify, merge, publish,
+// distribute, sublicense, and/or sell copies of the Software, and to permit
+// persons to whom the Software is furnished to do so, subject to the
+// following conditions:
+//
+// The above copyright notice and this permission notice shall be included
+// in all copies or substantial portions of the Software.
+//
+// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
+// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
+// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
+// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
+// USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+var Transform = require('_stream_transform');
+
+var binding = require('./binding');
+var util = require('util');
+var assert = require('assert').ok;
+
+// 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
+Object.keys(binding).forEach(function(k) {
+  if (k.match(/^Z/)) exports[k] = binding[k];
+});
+
+// translation table for return codes.
+exports.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
+};
+
+Object.keys(exports.codes).forEach(function(k) {
+  exports.codes[exports.codes[k]] = k;
+});
+
+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 = Buffer.concat(buffers, nread);
+    buffers = [];
+    callback(null, buf);
+    engine.close();
+  }
+}
+
+function zlibBufferSync(engine, buffer) {
+  if (typeof buffer === 'string')
+    buffer = new Buffer(buffer);
+  if (!Buffer.isBuffer(buffer))
+    throw new TypeError('Not a string or buffer');
+
+  var flushFlag = binding.Z_FINISH;
+
+  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);
+}
+
+
+// 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) {
+    if (opts.flush !== binding.Z_NO_FLUSH &&
+        opts.flush !== binding.Z_PARTIAL_FLUSH &&
+        opts.flush !== binding.Z_SYNC_FLUSH &&
+        opts.flush !== binding.Z_FULL_FLUSH &&
+        opts.flush !== binding.Z_FINISH &&
+        opts.flush !== binding.Z_BLOCK) {
+      throw new Error('Invalid flush flag: ' + opts.flush);
+    }
+  }
+  this._flushFlag = opts.flush || binding.Z_NO_FLUSH;
+
+  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._binding = new binding.Zlib(mode);
+
+  var self = this;
+  this._hadError = false;
+  this._binding.onerror = function(message, errno) {
+    // there is no way to cleanly recover.
+    // continuing only obscures problems.
+    self._binding = null;
+    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._binding.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS,
+                     level,
+                     opts.memLevel || exports.Z_DEFAULT_MEMLEVEL,
+                     strategy,
+                     opts.dictionary);
+
+  this._buffer = new Buffer(this._chunkSize);
+  this._offset = 0;
+  this._closed = false;
+  this._level = level;
+  this._strategy = strategy;
+
+  this.once('end', this.close);
+}
+
+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() {
+      self._binding.params(level, strategy);
+      if (!self._hadError) {
+        self._level = level;
+        self._strategy = strategy;
+        if (callback) callback();
+      }
+    });
+  } else {
+    process.nextTick(callback);
+  }
+};
+
+Zlib.prototype.reset = function() {
+  return this._binding.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(new Buffer(0), '', callback);
+};
+
+Zlib.prototype.flush = function(kind, callback) {
+  var ws = this._writableState;
+
+  if (typeof kind === 'function' || (kind === void 0 && !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) {
+    var self = this;
+    this.once('drain', function() {
+      self.flush(callback);
+    });
+  } else {
+    this._flushFlag = kind;
+    this.write(new Buffer(0), '', callback);
+  }
+};
+
+Zlib.prototype.close = function(callback) {
+  if (callback)
+    process.nextTick(callback);
+
+  if (this._closed)
+    return;
+
+  this._closed = true;
+
+  this._binding.close();
+
+  var self = this;
+  process.nextTick(function() {
+    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 it's the last chunk, or a final flush, we use the Z_FINISH flush flag.
+  // 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 = binding.Z_FINISH;
+  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;
+    }
+  }
+
+  var self = this;
+  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;
+    });
+
+    do {
+      var res = this._binding.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;
+    }
+
+    var buf = Buffer.concat(buffers, nread);
+    this.close();
+
+    return buf;
+  }
+
+  var req = this._binding.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) {
+    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 = new Buffer(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._binding.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);