mirror of
https://github.com/nodejs/node.git
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426 lines
11 KiB
JavaScript
426 lines
11 KiB
JavaScript
// Copyright Joyent, Inc. and other Node contributors.
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//
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// Permission is hereby granted, free of charge, to any person obtaining a
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// copy of this software and associated documentation files (the
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// "Software"), to deal in the Software without restriction, including
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// without limitation the rights to use, copy, modify, merge, publish,
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// distribute, sublicense, and/or sell copies of the Software, and to permit
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// persons to whom the Software is furnished to do so, subject to the
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// following conditions:
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//
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// The above copyright notice and this permission notice shall be included
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// in all copies or substantial portions of the Software.
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//
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// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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// OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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// MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN
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// NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM,
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// DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR
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// OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE
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// USE OR OTHER DEALINGS IN THE SOFTWARE.
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var binding = process.binding('zlib');
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var util = require('util');
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var stream = require('stream');
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var assert = require('assert').ok;
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// zlib doesn't provide these, so kludge them in following the same
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// const naming scheme zlib uses.
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binding.Z_MIN_WINDOWBITS = 8;
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binding.Z_MAX_WINDOWBITS = 15;
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binding.Z_DEFAULT_WINDOWBITS = 15;
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// fewer than 64 bytes per chunk is stupid.
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// technically it could work with as few as 8, but even 64 bytes
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// is absurdly low. Usually a MB or more is best.
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binding.Z_MIN_CHUNK = 64;
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binding.Z_MAX_CHUNK = Infinity;
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binding.Z_DEFAULT_CHUNK = (16 * 1024);
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binding.Z_MIN_MEMLEVEL = 1;
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binding.Z_MAX_MEMLEVEL = 9;
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binding.Z_DEFAULT_MEMLEVEL = 8;
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binding.Z_MIN_LEVEL = -1;
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binding.Z_MAX_LEVEL = 9;
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binding.Z_DEFAULT_LEVEL = binding.Z_DEFAULT_COMPRESSION;
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// expose all the zlib constants
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Object.keys(binding).forEach(function(k) {
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if (k.match(/^Z/)) exports[k] = binding[k];
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});
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exports.Deflate = Deflate;
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exports.Inflate = Inflate;
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exports.Gzip = Gzip;
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exports.Gunzip = Gunzip;
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exports.DeflateRaw = DeflateRaw;
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exports.InflateRaw = InflateRaw;
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exports.Unzip = Unzip;
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exports.createDeflate = function(o) {
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return new Deflate(o);
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};
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exports.createInflate = function(o) {
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return new Inflate(o);
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};
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exports.createDeflateRaw = function(o) {
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return new DeflateRaw(o);
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};
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exports.createInflateRaw = function(o) {
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return new InflateRaw(o);
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};
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exports.createGzip = function(o) {
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return new Gzip(o);
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};
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exports.createGunzip = function(o) {
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return new Gunzip(o);
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};
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exports.createUnzip = function(o) {
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return new Unzip(o);
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};
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// Convenience methods.
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// compress/decompress a string or buffer in one step.
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exports.deflate = function(buffer, callback) {
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zlibBuffer(new Deflate(), buffer, callback);
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};
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exports.gzip = function(buffer, callback) {
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zlibBuffer(new Gzip(), buffer, callback);
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};
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exports.deflateRaw = function(buffer, callback) {
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zlibBuffer(new DeflateRaw(), buffer, callback);
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};
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exports.unzip = function(buffer, callback) {
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zlibBuffer(new Unzip(), buffer, callback);
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};
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exports.inflate = function(buffer, callback) {
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zlibBuffer(new Inflate(), buffer, callback);
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};
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exports.gunzip = function(buffer, callback) {
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zlibBuffer(new Gunzip(), buffer, callback);
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};
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exports.inflateRaw = function(buffer, callback) {
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zlibBuffer(new InflateRaw(), buffer, callback);
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};
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function zlibBuffer(engine, buffer, callback) {
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var buffers = [];
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var nread = 0;
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function onError(err) {
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engine.removeListener('end', onEnd);
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engine.removeListener('error', onError);
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callback(err);
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}
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function onData(chunk) {
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buffers.push(chunk);
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nread += chunk.length;
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}
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function onEnd() {
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var buffer;
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switch(buffers.length) {
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case 0:
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buffer = new Buffer(0);
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break;
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case 1:
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buffer = buffers[0];
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break;
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default:
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buffer = new Buffer(nread);
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var n = 0;
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buffers.forEach(function(b) {
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var l = b.length;
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b.copy(buffer, n, 0, l);
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n += l;
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});
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break;
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}
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callback(null, buffer);
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}
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engine.on('error', onError);
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engine.on('data', onData);
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engine.on('end', onEnd);
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engine.write(buffer);
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engine.end();
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}
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// generic zlib
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// minimal 2-byte header
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function Deflate(opts) {
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if (!(this instanceof Deflate)) return new Deflate(opts);
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Zlib.call(this, opts, binding.Deflate);
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}
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function Inflate(opts) {
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if (!(this instanceof Inflate)) return new Inflate(opts);
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Zlib.call(this, opts, binding.Inflate);
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}
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// gzip - bigger header, same deflate compression
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function Gzip(opts) {
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if (!(this instanceof Gzip)) return new Gzip(opts);
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Zlib.call(this, opts, binding.Gzip);
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}
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function Gunzip(opts) {
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if (!(this instanceof Gunzip)) return new Gunzip(opts);
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Zlib.call(this, opts, binding.Gunzip);
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}
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// raw - no header
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function DeflateRaw(opts) {
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if (!(this instanceof DeflateRaw)) return new DeflateRaw(opts);
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Zlib.call(this, opts, binding.DeflateRaw);
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}
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function InflateRaw(opts) {
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if (!(this instanceof InflateRaw)) return new InflateRaw(opts);
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Zlib.call(this, opts, binding.InflateRaw);
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}
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// auto-detect header.
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function Unzip(opts) {
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if (!(this instanceof Unzip)) return new Unzip(opts);
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Zlib.call(this, opts, binding.Unzip);
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}
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// the Zlib class they all inherit from
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// This thing manages the queue of requests, and returns
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// true or false if there is anything in the queue when
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// you call the .write() method.
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function Zlib(opts, Binding) {
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this._opts = opts = opts || {};
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this._queue = [];
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this._processing = false;
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this._ended = false;
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this.readable = true;
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this.writable = true;
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this._flush = binding.Z_NO_FLUSH;
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if (opts.chunkSize) {
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if (opts.chunkSize < exports.Z_MIN_CHUNK ||
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opts.chunkSize > exports.Z_MAX_CHUNK) {
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throw new Error('Invalid chunk size: ' + opts.chunkSize);
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}
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}
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if (opts.windowBits) {
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if (opts.windowBits < exports.Z_MIN_WINDOWBITS ||
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opts.windowBits > exports.Z_MAX_WINDOWBITS) {
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throw new Error('Invalid windowBits: ' + opts.windowBits);
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}
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}
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if (opts.level) {
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if (opts.level < exports.Z_MIN_LEVEL ||
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opts.level > exports.Z_MAX_LEVEL) {
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throw new Error('Invalid compression level: ' + opts.level);
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}
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}
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if (opts.memLevel) {
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if (opts.memLevel < exports.Z_MIN_MEMLEVEL ||
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opts.memLevel > exports.Z_MAX_MEMLEVEL) {
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throw new Error('Invalid memLevel: ' + opts.memLevel);
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}
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}
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if (opts.strategy) {
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if (opts.strategy != exports.Z_FILTERED &&
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opts.strategy != exports.Z_HUFFMAN_ONLY &&
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opts.strategy != exports.Z_RLE &&
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opts.strategy != exports.Z_FIXED &&
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opts.strategy != exports.Z_DEFAULT_STRATEGY) {
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throw new Error('Invalid strategy: ' + opts.strategy);
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}
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}
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this._binding = new Binding();
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this._binding.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS,
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opts.level || exports.Z_DEFAULT_COMPRESSION,
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opts.memLevel || exports.Z_DEFAULT_MEMLEVEL,
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opts.strategy || exports.Z_DEFAULT_STRATEGY);
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this._chunkSize = opts.chunkSize || exports.Z_DEFAULT_CHUNK;
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this._buffer = new Buffer(this._chunkSize);
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this._offset = 0;
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var self = this;
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}
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util.inherits(Zlib, stream.Stream);
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Zlib.prototype.write = function write(chunk, cb) {
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if (this._ended) {
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return this.emit('error', new Error('Cannot write after end'));
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}
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if (arguments.length === 1 && typeof chunk === 'function') {
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cb = chunk;
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chunk = null;
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}
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if (!chunk) {
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chunk = null;
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} else if (typeof chunk === 'string') {
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chunk = new Buffer(chunk);
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} else if (!Buffer.isBuffer(chunk)) {
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return this.emit('error', new Error('Invalid argument'));
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}
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var empty = this._queue.length === 0;
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this._queue.push([chunk, cb]);
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this._process();
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if (!empty) {
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this._needDrain = true;
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}
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return empty;
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};
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Zlib.prototype.flush = function flush(cb) {
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this._flush = binding.Z_SYNC_FLUSH;
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return this.write(cb);
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};
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Zlib.prototype.end = function end(chunk, cb) {
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var self = this;
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this._ending = true;
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var ret = this.write(chunk, function() {
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self.emit('end');
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if (cb) cb();
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});
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this._ended = true;
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return ret;
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};
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Zlib.prototype._process = function() {
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if (this._processing || this._paused) return;
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if (this._queue.length === 0) {
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if (this._needDrain) {
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this._needDrain = false;
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this.emit('drain');
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}
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// nothing to do, waiting for more data at this point.
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return;
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}
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var req = this._queue.shift();
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var cb = req.pop();
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var chunk = req.pop();
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if (this._ending && this._queue.length === 0) {
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this._flush = binding.Z_FINISH;
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}
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var self = this;
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var availInBefore = chunk && chunk.length;
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var availOutBefore = this._chunkSize - this._offset;
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var inOff = 0;
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var req = this._binding.write(this._flush,
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chunk, // in
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inOff, // in_off
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availInBefore, // in_len
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this._buffer, // out
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this._offset, //out_off
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availOutBefore); // out_len
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req.buffer = chunk;
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req.callback = callback;
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this._processing = req;
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function callback(availInAfter, availOutAfter, buffer) {
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var have = availOutBefore - availOutAfter;
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assert(have >= 0, 'have should not go down');
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if (have > 0) {
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var out = self._buffer.slice(self._offset, self._offset + have);
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self._offset += have;
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self.emit('data', out);
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}
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// XXX Maybe have a 'min buffer' size so we don't dip into the
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// thread pool with only 1 byte available or something?
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if (availOutAfter === 0 || self._offset >= self._chunkSize) {
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availOutBefore = self._chunkSize;
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self._offset = 0;
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self._buffer = new Buffer(self._chunkSize);
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}
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if (availOutAfter === 0) {
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// Not actually done. Need to reprocess.
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// Also, update the availInBefore to the availInAfter value,
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// so that if we have to hit it a third (fourth, etc.) time,
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// it'll have the correct byte counts.
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inOff += (availInBefore - availInAfter);
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availInBefore = availInAfter;
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var newReq = self._binding.write(self._flush,
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chunk,
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inOff,
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availInBefore,
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self._buffer,
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self._offset,
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self._chunkSize);
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newReq.callback = callback; // this same function
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newReq.buffer = chunk;
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self._processing = newReq;
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return;
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}
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// finished with the chunk.
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self._processing = false;
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if (cb) cb();
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self._process();
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}
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};
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Zlib.prototype.pause = function() {
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this._paused = true;
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this.emit('pause');
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};
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Zlib.prototype.resume = function() {
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this._paused = false;
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this._process();
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};
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util.inherits(Deflate, Zlib);
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util.inherits(Inflate, Zlib);
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util.inherits(Gzip, Zlib);
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util.inherits(Gunzip, Zlib);
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util.inherits(DeflateRaw, Zlib);
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util.inherits(InflateRaw, Zlib);
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util.inherits(Unzip, Zlib);
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