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609 lines
16 KiB
609 lines
16 KiB
'use strict';
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var Buffer = require('buffer').Buffer;
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var Transform = require('stream').Transform;
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var binding = require('./binding');
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var util = require('util');
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var assert = require('assert').ok;
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var kMaxLength = require('buffer').kMaxLength;
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var kRangeErrorMessage = 'Cannot create final Buffer. It would be larger ' + 'than 0x' + kMaxLength.toString(16) + ' bytes';
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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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var bkeys = Object.keys(binding);
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for (var bk = 0; bk < bkeys.length; bk++) {
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var bkey = bkeys[bk];
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if (bkey.match(/^Z/)) {
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Object.defineProperty(exports, bkey, {
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enumerable: true, value: binding[bkey], writable: false
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});
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}
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}
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// translation table for return codes.
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var codes = {
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Z_OK: binding.Z_OK,
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Z_STREAM_END: binding.Z_STREAM_END,
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Z_NEED_DICT: binding.Z_NEED_DICT,
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Z_ERRNO: binding.Z_ERRNO,
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Z_STREAM_ERROR: binding.Z_STREAM_ERROR,
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Z_DATA_ERROR: binding.Z_DATA_ERROR,
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Z_MEM_ERROR: binding.Z_MEM_ERROR,
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Z_BUF_ERROR: binding.Z_BUF_ERROR,
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Z_VERSION_ERROR: binding.Z_VERSION_ERROR
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};
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var ckeys = Object.keys(codes);
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for (var ck = 0; ck < ckeys.length; ck++) {
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var ckey = ckeys[ck];
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codes[codes[ckey]] = ckey;
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}
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Object.defineProperty(exports, 'codes', {
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enumerable: true, value: Object.freeze(codes), writable: false
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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, opts, callback) {
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if (typeof opts === 'function') {
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callback = opts;
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opts = {};
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}
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return zlibBuffer(new Deflate(opts), buffer, callback);
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};
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exports.deflateSync = function (buffer, opts) {
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return zlibBufferSync(new Deflate(opts), buffer);
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};
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exports.gzip = function (buffer, opts, callback) {
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if (typeof opts === 'function') {
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callback = opts;
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opts = {};
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}
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return zlibBuffer(new Gzip(opts), buffer, callback);
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};
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exports.gzipSync = function (buffer, opts) {
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return zlibBufferSync(new Gzip(opts), buffer);
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};
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exports.deflateRaw = function (buffer, opts, callback) {
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if (typeof opts === 'function') {
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callback = opts;
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opts = {};
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}
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return zlibBuffer(new DeflateRaw(opts), buffer, callback);
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};
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exports.deflateRawSync = function (buffer, opts) {
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return zlibBufferSync(new DeflateRaw(opts), buffer);
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};
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exports.unzip = function (buffer, opts, callback) {
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if (typeof opts === 'function') {
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callback = opts;
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opts = {};
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}
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return zlibBuffer(new Unzip(opts), buffer, callback);
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};
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exports.unzipSync = function (buffer, opts) {
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return zlibBufferSync(new Unzip(opts), buffer);
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};
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exports.inflate = function (buffer, opts, callback) {
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if (typeof opts === 'function') {
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callback = opts;
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opts = {};
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}
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return zlibBuffer(new Inflate(opts), buffer, callback);
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};
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exports.inflateSync = function (buffer, opts) {
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return zlibBufferSync(new Inflate(opts), buffer);
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};
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exports.gunzip = function (buffer, opts, callback) {
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if (typeof opts === 'function') {
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callback = opts;
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opts = {};
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}
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return zlibBuffer(new Gunzip(opts), buffer, callback);
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};
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exports.gunzipSync = function (buffer, opts) {
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return zlibBufferSync(new Gunzip(opts), buffer);
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};
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exports.inflateRaw = function (buffer, opts, callback) {
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if (typeof opts === 'function') {
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callback = opts;
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opts = {};
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}
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return zlibBuffer(new InflateRaw(opts), buffer, callback);
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};
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exports.inflateRawSync = function (buffer, opts) {
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return zlibBufferSync(new InflateRaw(opts), buffer);
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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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engine.on('error', onError);
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engine.on('end', onEnd);
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engine.end(buffer);
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flow();
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function flow() {
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var chunk;
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while (null !== (chunk = engine.read())) {
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buffers.push(chunk);
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nread += chunk.length;
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}
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engine.once('readable', flow);
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}
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function onError(err) {
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engine.removeListener('end', onEnd);
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engine.removeListener('readable', flow);
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callback(err);
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}
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function onEnd() {
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var buf;
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var err = null;
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if (nread >= kMaxLength) {
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err = new RangeError(kRangeErrorMessage);
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} else {
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buf = Buffer.concat(buffers, nread);
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}
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buffers = [];
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engine.close();
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callback(err, buf);
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}
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}
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function zlibBufferSync(engine, buffer) {
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if (typeof buffer === 'string') buffer = Buffer.from(buffer);
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if (!Buffer.isBuffer(buffer)) throw new TypeError('Not a string or buffer');
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var flushFlag = engine._finishFlushFlag;
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return engine._processChunk(buffer, flushFlag);
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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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function isValidFlushFlag(flag) {
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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;
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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, mode) {
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var _this = this;
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this._opts = opts = opts || {};
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this._chunkSize = opts.chunkSize || exports.Z_DEFAULT_CHUNK;
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Transform.call(this, opts);
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if (opts.flush && !isValidFlushFlag(opts.flush)) {
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throw new Error('Invalid flush flag: ' + opts.flush);
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}
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if (opts.finishFlush && !isValidFlushFlag(opts.finishFlush)) {
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throw new Error('Invalid flush flag: ' + opts.finishFlush);
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}
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this._flushFlag = opts.flush || binding.Z_NO_FLUSH;
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this._finishFlushFlag = typeof opts.finishFlush !== 'undefined' ? opts.finishFlush : binding.Z_FINISH;
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if (opts.chunkSize) {
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if (opts.chunkSize < exports.Z_MIN_CHUNK || 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 || 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 || 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 || 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 && opts.strategy != exports.Z_HUFFMAN_ONLY && opts.strategy != exports.Z_RLE && opts.strategy != exports.Z_FIXED && 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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if (opts.dictionary) {
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if (!Buffer.isBuffer(opts.dictionary)) {
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throw new Error('Invalid dictionary: it should be a Buffer instance');
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}
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}
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this._handle = new binding.Zlib(mode);
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var self = this;
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this._hadError = false;
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this._handle.onerror = function (message, errno) {
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// there is no way to cleanly recover.
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// continuing only obscures problems.
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_close(self);
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self._hadError = true;
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var error = new Error(message);
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error.errno = errno;
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error.code = exports.codes[errno];
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self.emit('error', error);
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};
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var level = exports.Z_DEFAULT_COMPRESSION;
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if (typeof opts.level === 'number') level = opts.level;
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var strategy = exports.Z_DEFAULT_STRATEGY;
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if (typeof opts.strategy === 'number') strategy = opts.strategy;
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this._handle.init(opts.windowBits || exports.Z_DEFAULT_WINDOWBITS, level, opts.memLevel || exports.Z_DEFAULT_MEMLEVEL, strategy, opts.dictionary);
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this._buffer = Buffer.allocUnsafe(this._chunkSize);
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this._offset = 0;
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this._level = level;
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this._strategy = strategy;
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this.once('end', this.close);
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Object.defineProperty(this, '_closed', {
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get: function () {
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return !_this._handle;
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},
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configurable: true,
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enumerable: true
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});
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}
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util.inherits(Zlib, Transform);
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Zlib.prototype.params = function (level, strategy, callback) {
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if (level < exports.Z_MIN_LEVEL || level > exports.Z_MAX_LEVEL) {
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throw new RangeError('Invalid compression level: ' + level);
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}
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if (strategy != exports.Z_FILTERED && strategy != exports.Z_HUFFMAN_ONLY && strategy != exports.Z_RLE && strategy != exports.Z_FIXED && strategy != exports.Z_DEFAULT_STRATEGY) {
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throw new TypeError('Invalid strategy: ' + strategy);
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}
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if (this._level !== level || this._strategy !== strategy) {
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var self = this;
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this.flush(binding.Z_SYNC_FLUSH, function () {
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assert(self._handle, 'zlib binding closed');
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self._handle.params(level, strategy);
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if (!self._hadError) {
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self._level = level;
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self._strategy = strategy;
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if (callback) callback();
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}
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});
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} else {
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process.nextTick(callback);
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}
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};
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Zlib.prototype.reset = function () {
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assert(this._handle, 'zlib binding closed');
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return this._handle.reset();
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};
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// This is the _flush function called by the transform class,
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// internally, when the last chunk has been written.
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Zlib.prototype._flush = function (callback) {
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this._transform(Buffer.alloc(0), '', callback);
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};
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Zlib.prototype.flush = function (kind, callback) {
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var _this2 = this;
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var ws = this._writableState;
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if (typeof kind === 'function' || kind === undefined && !callback) {
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callback = kind;
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kind = binding.Z_FULL_FLUSH;
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}
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if (ws.ended) {
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if (callback) process.nextTick(callback);
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} else if (ws.ending) {
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if (callback) this.once('end', callback);
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} else if (ws.needDrain) {
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if (callback) {
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this.once('drain', function () {
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return _this2.flush(kind, callback);
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});
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}
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} else {
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this._flushFlag = kind;
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this.write(Buffer.alloc(0), '', callback);
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}
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};
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Zlib.prototype.close = function (callback) {
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_close(this, callback);
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process.nextTick(emitCloseNT, this);
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};
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function _close(engine, callback) {
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if (callback) process.nextTick(callback);
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// Caller may invoke .close after a zlib error (which will null _handle).
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if (!engine._handle) return;
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engine._handle.close();
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engine._handle = null;
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}
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function emitCloseNT(self) {
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self.emit('close');
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}
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Zlib.prototype._transform = function (chunk, encoding, cb) {
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var flushFlag;
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var ws = this._writableState;
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var ending = ws.ending || ws.ended;
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var last = ending && (!chunk || ws.length === chunk.length);
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if (chunk !== null && !Buffer.isBuffer(chunk)) return cb(new Error('invalid input'));
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if (!this._handle) return cb(new Error('zlib binding closed'));
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// If it's the last chunk, or a final flush, we use the Z_FINISH flush flag
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// (or whatever flag was provided using opts.finishFlush).
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// If it's explicitly flushing at some other time, then we use
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// Z_FULL_FLUSH. Otherwise, use Z_NO_FLUSH for maximum compression
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// goodness.
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if (last) flushFlag = this._finishFlushFlag;else {
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flushFlag = this._flushFlag;
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// once we've flushed the last of the queue, stop flushing and
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// go back to the normal behavior.
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if (chunk.length >= ws.length) {
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this._flushFlag = this._opts.flush || binding.Z_NO_FLUSH;
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}
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}
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this._processChunk(chunk, flushFlag, cb);
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};
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Zlib.prototype._processChunk = function (chunk, flushFlag, cb) {
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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 self = this;
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var async = typeof cb === 'function';
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if (!async) {
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var buffers = [];
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var nread = 0;
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var error;
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this.on('error', function (er) {
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error = er;
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});
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assert(this._handle, 'zlib binding closed');
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do {
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var res = this._handle.writeSync(flushFlag, 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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} while (!this._hadError && callback(res[0], res[1]));
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if (this._hadError) {
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throw error;
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}
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if (nread >= kMaxLength) {
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_close(this);
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throw new RangeError(kRangeErrorMessage);
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}
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var buf = Buffer.concat(buffers, nread);
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_close(this);
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return buf;
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}
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assert(this._handle, 'zlib binding closed');
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var req = this._handle.write(flushFlag, 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;
|
|
|
|
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);
|