433 lines
11 KiB
JavaScript
433 lines
11 KiB
JavaScript
'use strict'
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/* eslint camelcase: "off" */
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var assert = require('assert')
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var Zstream = require('pako/lib/zlib/zstream')
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var zlib_deflate = require('pako/lib/zlib/deflate.js')
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var zlib_inflate = require('pako/lib/zlib/inflate.js')
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var constants = require('pako/lib/zlib/constants')
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for (var key in constants) {
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exports[key] = constants[key]
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}
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// zlib modes
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exports.NONE = 0
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exports.DEFLATE = 1
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exports.INFLATE = 2
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exports.GZIP = 3
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exports.GUNZIP = 4
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exports.DEFLATERAW = 5
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exports.INFLATERAW = 6
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exports.UNZIP = 7
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var GZIP_HEADER_ID1 = 0x1f
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var GZIP_HEADER_ID2 = 0x8b
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/**
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* Emulate Node's zlib C++ layer for use by the JS layer in index.js
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*/
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function Zlib (mode) {
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if (typeof mode !== 'number' || mode < exports.DEFLATE || mode > exports.UNZIP) {
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throw new TypeError('Bad argument')
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}
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this.dictionary = null
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this.err = 0
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this.flush = 0
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this.init_done = false
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this.level = 0
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this.memLevel = 0
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this.mode = mode
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this.strategy = 0
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this.windowBits = 0
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this.write_in_progress = false
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this.pending_close = false
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this.gzip_id_bytes_read = 0
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}
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Zlib.prototype.close = function () {
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if (this.write_in_progress) {
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this.pending_close = true
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return
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}
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this.pending_close = false
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assert(this.init_done, 'close before init')
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assert(this.mode <= exports.UNZIP)
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if (this.mode === exports.DEFLATE || this.mode === exports.GZIP || this.mode === exports.DEFLATERAW) {
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zlib_deflate.deflateEnd(this.strm)
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} else if (this.mode === exports.INFLATE || this.mode === exports.GUNZIP ||
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this.mode === exports.INFLATERAW || this.mode === exports.UNZIP) {
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zlib_inflate.inflateEnd(this.strm)
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}
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this.mode = exports.NONE
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this.dictionary = null
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}
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Zlib.prototype.write = function (flush, input, in_off, in_len, out, out_off, out_len) {
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return this._write(true, flush, input, in_off, in_len, out, out_off, out_len)
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}
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Zlib.prototype.writeSync = function (flush, input, in_off, in_len, out, out_off, out_len) {
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return this._write(false, flush, input, in_off, in_len, out, out_off, out_len)
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}
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Zlib.prototype._write = function (async, flush, input, in_off, in_len, out, out_off, out_len) {
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assert.equal(arguments.length, 8)
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assert(this.init_done, 'write before init')
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assert(this.mode !== exports.NONE, 'already finalized')
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assert.equal(false, this.write_in_progress, 'write already in progress')
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assert.equal(false, this.pending_close, 'close is pending')
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this.write_in_progress = true
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assert.equal(false, flush === undefined, 'must provide flush value')
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this.write_in_progress = true
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if (flush !== exports.Z_NO_FLUSH &&
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flush !== exports.Z_PARTIAL_FLUSH &&
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flush !== exports.Z_SYNC_FLUSH &&
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flush !== exports.Z_FULL_FLUSH &&
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flush !== exports.Z_FINISH &&
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flush !== exports.Z_BLOCK) {
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throw new Error('Invalid flush value')
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}
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if (input == null) {
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input = Buffer.alloc(0)
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in_len = 0
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in_off = 0
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}
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this.strm.avail_in = in_len
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this.strm.input = input
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this.strm.next_in = in_off
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this.strm.avail_out = out_len
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this.strm.output = out
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this.strm.next_out = out_off
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this.flush = flush
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if (!async) {
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// sync version
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this._process()
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if (this._checkError()) {
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return this._afterSync()
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}
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return
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}
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// async version
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var self = this
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process.nextTick(function () {
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self._process()
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self._after()
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})
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return this
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}
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Zlib.prototype._afterSync = function () {
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var avail_out = this.strm.avail_out
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var avail_in = this.strm.avail_in
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this.write_in_progress = false
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return [avail_in, avail_out]
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}
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Zlib.prototype._process = function () {
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var next_expected_header_byte = null
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// If the avail_out is left at 0, then it means that it ran out
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// of room. If there was avail_out left over, then it means
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// that all of the input was consumed.
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switch (this.mode) {
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case exports.DEFLATE:
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case exports.GZIP:
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case exports.DEFLATERAW:
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this.err = zlib_deflate.deflate(this.strm, this.flush)
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break
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case exports.UNZIP:
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if (this.strm.avail_in > 0) {
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next_expected_header_byte = this.strm.next_in
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}
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switch (this.gzip_id_bytes_read) {
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case 0:
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if (next_expected_header_byte === null) {
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break
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}
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if (this.strm.input[next_expected_header_byte] === GZIP_HEADER_ID1) {
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this.gzip_id_bytes_read = 1
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next_expected_header_byte++
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if (this.strm.avail_in === 1) {
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// The only available byte was already read.
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break
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}
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} else {
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this.mode = exports.INFLATE
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break
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}
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// fallthrough
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case 1:
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if (next_expected_header_byte === null) {
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break
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}
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if (this.strm.input[next_expected_header_byte] === GZIP_HEADER_ID2) {
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this.gzip_id_bytes_read = 2
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this.mode = exports.GUNZIP
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} else {
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// There is no actual difference between INFLATE and INFLATERAW
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// (after initialization).
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this.mode = exports.INFLATE
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}
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break
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default:
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throw new Error('invalid number of gzip magic number bytes read')
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}
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// fallthrough
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case exports.INFLATE:
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case exports.GUNZIP:
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case exports.INFLATERAW:
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this.err = zlib_inflate.inflate(this.strm, this.flush)
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// If data was encoded with dictionary
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if (this.err === exports.Z_NEED_DICT && this.dictionary) {
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// Load it
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this.err = zlib_inflate.inflateSetDictionary(this.strm, this.dictionary)
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if (this.err === exports.Z_OK) {
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// And try to decode again
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this.err = zlib_inflate.inflate(this.strm, this.flush)
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} else if (this.err === exports.Z_DATA_ERROR) {
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// Both inflateSetDictionary() and inflate() return Z_DATA_ERROR.
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// Make it possible for After() to tell a bad dictionary from bad
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// input.
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this.err = exports.Z_NEED_DICT
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}
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}
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while (this.strm.avail_in > 0 &&
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this.mode === exports.GUNZIP &&
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this.err === exports.Z_STREAM_END &&
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this.strm.next_in[0] !== 0x00) {
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// Bytes remain in input buffer. Perhaps this is another compressed
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// member in the same archive, or just trailing garbage.
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// Trailing zero bytes are okay, though, since they are frequently
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// used for padding.
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this.reset()
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this.err = zlib_inflate.inflate(this.strm, this.flush)
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}
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break
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default:
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throw new Error('Unknown mode ' + this.mode)
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}
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}
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Zlib.prototype._checkError = function () {
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// Acceptable error states depend on the type of zlib stream.
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switch (this.err) {
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case exports.Z_OK:
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case exports.Z_BUF_ERROR:
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if (this.strm.avail_out !== 0 && this.flush === exports.Z_FINISH) {
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this._error('unexpected end of file')
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return false
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}
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break
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case exports.Z_STREAM_END:
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// normal statuses, not fatal
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break
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case exports.Z_NEED_DICT:
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if (this.dictionary == null) {
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this._error('Missing dictionary')
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} else {
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this._error('Bad dictionary')
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}
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return false
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default:
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// something else.
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this._error('Zlib error')
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return false
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}
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return true
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}
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Zlib.prototype._after = function () {
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if (!this._checkError()) {
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return
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}
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var avail_out = this.strm.avail_out
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var avail_in = this.strm.avail_in
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this.write_in_progress = false
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// call the write() cb
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this.callback(avail_in, avail_out)
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if (this.pending_close) {
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this.close()
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}
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}
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Zlib.prototype._error = function (message) {
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if (this.strm.msg) {
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message = this.strm.msg
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}
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this.onerror(message, this.err)
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// no hope of rescue.
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this.write_in_progress = false
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if (this.pending_close) {
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this.close()
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}
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}
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Zlib.prototype.init = function (windowBits, level, memLevel, strategy, dictionary) {
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assert(arguments.length === 4 || arguments.length === 5, 'init(windowBits, level, memLevel, strategy, [dictionary])')
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assert(windowBits >= 8 && windowBits <= 15, 'invalid windowBits')
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assert(level >= -1 && level <= 9, 'invalid compression level')
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assert(memLevel >= 1 && memLevel <= 9, 'invalid memlevel')
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assert(strategy === exports.Z_FILTERED ||
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strategy === exports.Z_HUFFMAN_ONLY ||
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strategy === exports.Z_RLE ||
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strategy === exports.Z_FIXED ||
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strategy === exports.Z_DEFAULT_STRATEGY, 'invalid strategy')
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this._init(level, windowBits, memLevel, strategy, dictionary)
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this._setDictionary()
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}
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Zlib.prototype.params = function () {
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throw new Error('deflateParams Not supported')
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}
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Zlib.prototype.reset = function () {
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this._reset()
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this._setDictionary()
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}
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Zlib.prototype._init = function (level, windowBits, memLevel, strategy, dictionary) {
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this.level = level
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this.windowBits = windowBits
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this.memLevel = memLevel
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this.strategy = strategy
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this.flush = exports.Z_NO_FLUSH
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this.err = exports.Z_OK
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if (this.mode === exports.GZIP || this.mode === exports.GUNZIP) {
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this.windowBits += 16
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}
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if (this.mode === exports.UNZIP) {
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this.windowBits += 32
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}
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if (this.mode === exports.DEFLATERAW || this.mode === exports.INFLATERAW) {
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this.windowBits = -1 * this.windowBits
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}
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this.strm = new Zstream()
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switch (this.mode) {
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case exports.DEFLATE:
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case exports.GZIP:
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case exports.DEFLATERAW:
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this.err = zlib_deflate.deflateInit2(
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this.strm,
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this.level,
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exports.Z_DEFLATED,
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this.windowBits,
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this.memLevel,
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this.strategy
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)
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break
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case exports.INFLATE:
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case exports.GUNZIP:
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case exports.INFLATERAW:
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case exports.UNZIP:
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this.err = zlib_inflate.inflateInit2(
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this.strm,
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this.windowBits
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)
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break
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default:
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throw new Error('Unknown mode ' + this.mode)
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}
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if (this.err !== exports.Z_OK) {
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this._error('Init error')
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}
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this.dictionary = dictionary
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this.write_in_progress = false
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this.init_done = true
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}
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Zlib.prototype._setDictionary = function () {
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if (this.dictionary == null) {
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return
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}
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this.err = exports.Z_OK
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switch (this.mode) {
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case exports.DEFLATE:
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case exports.DEFLATERAW:
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this.err = zlib_deflate.deflateSetDictionary(this.strm, this.dictionary)
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break
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default:
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break
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}
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if (this.err !== exports.Z_OK) {
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this._error('Failed to set dictionary')
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}
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}
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Zlib.prototype._reset = function () {
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this.err = exports.Z_OK
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switch (this.mode) {
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case exports.DEFLATE:
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case exports.DEFLATERAW:
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case exports.GZIP:
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this.err = zlib_deflate.deflateReset(this.strm)
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break
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case exports.INFLATE:
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case exports.INFLATERAW:
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case exports.GUNZIP:
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this.err = zlib_inflate.inflateReset(this.strm)
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break
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default:
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break
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}
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if (this.err !== exports.Z_OK) {
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this._error('Failed to reset stream')
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}
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}
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exports.Zlib = Zlib
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