424 lines
12 KiB
JavaScript
424 lines
12 KiB
JavaScript
'use strict';
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var zlib_inflate = require('./zlib/inflate');
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var utils = require('./utils/common');
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var strings = require('./utils/strings');
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var c = require('./zlib/constants');
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var msg = require('./zlib/messages');
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var ZStream = require('./zlib/zstream');
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var GZheader = require('./zlib/gzheader');
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var toString = Object.prototype.toString;
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/**
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* class Inflate
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*
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* Generic JS-style wrapper for zlib calls. If you don't need
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* streaming behaviour - use more simple functions: [[inflate]]
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* and [[inflateRaw]].
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**/
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/* internal
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* inflate.chunks -> Array
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*
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* Chunks of output data, if [[Inflate#onData]] not overridden.
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**/
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/**
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* Inflate.result -> Uint8Array|Array|String
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*
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* Uncompressed result, generated by default [[Inflate#onData]]
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* and [[Inflate#onEnd]] handlers. Filled after you push last chunk
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* (call [[Inflate#push]] with `Z_FINISH` / `true` param) or if you
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* push a chunk with explicit flush (call [[Inflate#push]] with
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* `Z_SYNC_FLUSH` param).
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**/
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/**
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* Inflate.err -> Number
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*
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* Error code after inflate finished. 0 (Z_OK) on success.
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* Should be checked if broken data possible.
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**/
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/**
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* Inflate.msg -> String
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*
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* Error message, if [[Inflate.err]] != 0
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**/
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/**
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* new Inflate(options)
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* - options (Object): zlib inflate options.
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*
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* Creates new inflator instance with specified params. Throws exception
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* on bad params. Supported options:
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*
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* - `windowBits`
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* - `dictionary`
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*
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* [http://zlib.net/manual.html#Advanced](http://zlib.net/manual.html#Advanced)
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* for more information on these.
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*
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* Additional options, for internal needs:
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*
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* - `chunkSize` - size of generated data chunks (16K by default)
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* - `raw` (Boolean) - do raw inflate
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* - `to` (String) - if equal to 'string', then result will be converted
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* from utf8 to utf16 (javascript) string. When string output requested,
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* chunk length can differ from `chunkSize`, depending on content.
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*
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* By default, when no options set, autodetect deflate/gzip data format via
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* wrapper header.
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*
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* ##### Example:
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*
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* ```javascript
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* var pako = require('pako')
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* , chunk1 = Uint8Array([1,2,3,4,5,6,7,8,9])
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* , chunk2 = Uint8Array([10,11,12,13,14,15,16,17,18,19]);
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*
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* var inflate = new pako.Inflate({ level: 3});
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*
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* inflate.push(chunk1, false);
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* inflate.push(chunk2, true); // true -> last chunk
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*
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* if (inflate.err) { throw new Error(inflate.err); }
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*
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* console.log(inflate.result);
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* ```
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**/
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function Inflate(options) {
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if (!(this instanceof Inflate)) return new Inflate(options);
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this.options = utils.assign({
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chunkSize: 16384,
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windowBits: 0,
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to: ''
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}, options || {});
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var opt = this.options;
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// Force window size for `raw` data, if not set directly,
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// because we have no header for autodetect.
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if (opt.raw && (opt.windowBits >= 0) && (opt.windowBits < 16)) {
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opt.windowBits = -opt.windowBits;
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if (opt.windowBits === 0) { opt.windowBits = -15; }
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}
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// If `windowBits` not defined (and mode not raw) - set autodetect flag for gzip/deflate
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if ((opt.windowBits >= 0) && (opt.windowBits < 16) &&
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!(options && options.windowBits)) {
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opt.windowBits += 32;
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}
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// Gzip header has no info about windows size, we can do autodetect only
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// for deflate. So, if window size not set, force it to max when gzip possible
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if ((opt.windowBits > 15) && (opt.windowBits < 48)) {
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// bit 3 (16) -> gzipped data
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// bit 4 (32) -> autodetect gzip/deflate
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if ((opt.windowBits & 15) === 0) {
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opt.windowBits |= 15;
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}
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}
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this.err = 0; // error code, if happens (0 = Z_OK)
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this.msg = ''; // error message
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this.ended = false; // used to avoid multiple onEnd() calls
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this.chunks = []; // chunks of compressed data
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this.strm = new ZStream();
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this.strm.avail_out = 0;
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var status = zlib_inflate.inflateInit2(
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this.strm,
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opt.windowBits
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);
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if (status !== c.Z_OK) {
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throw new Error(msg[status]);
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}
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this.header = new GZheader();
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zlib_inflate.inflateGetHeader(this.strm, this.header);
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// Setup dictionary
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if (opt.dictionary) {
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// Convert data if needed
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if (typeof opt.dictionary === 'string') {
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opt.dictionary = strings.string2buf(opt.dictionary);
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} else if (toString.call(opt.dictionary) === '[object ArrayBuffer]') {
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opt.dictionary = new Uint8Array(opt.dictionary);
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}
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if (opt.raw) { //In raw mode we need to set the dictionary early
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status = zlib_inflate.inflateSetDictionary(this.strm, opt.dictionary);
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if (status !== c.Z_OK) {
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throw new Error(msg[status]);
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}
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}
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}
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}
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/**
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* Inflate#push(data[, mode]) -> Boolean
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* - data (Uint8Array|Array|ArrayBuffer|String): input data
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* - mode (Number|Boolean): 0..6 for corresponding Z_NO_FLUSH..Z_TREE modes.
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* See constants. Skipped or `false` means Z_NO_FLUSH, `true` means Z_FINISH.
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*
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* Sends input data to inflate pipe, generating [[Inflate#onData]] calls with
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* new output chunks. Returns `true` on success. The last data block must have
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* mode Z_FINISH (or `true`). That will flush internal pending buffers and call
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* [[Inflate#onEnd]]. For interim explicit flushes (without ending the stream) you
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* can use mode Z_SYNC_FLUSH, keeping the decompression context.
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*
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* On fail call [[Inflate#onEnd]] with error code and return false.
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*
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* We strongly recommend to use `Uint8Array` on input for best speed (output
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* format is detected automatically). Also, don't skip last param and always
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* use the same type in your code (boolean or number). That will improve JS speed.
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*
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* For regular `Array`-s make sure all elements are [0..255].
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*
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* ##### Example
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*
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* ```javascript
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* push(chunk, false); // push one of data chunks
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* ...
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* push(chunk, true); // push last chunk
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* ```
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**/
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Inflate.prototype.push = function (data, mode) {
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var strm = this.strm;
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var chunkSize = this.options.chunkSize;
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var dictionary = this.options.dictionary;
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var status, _mode;
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var next_out_utf8, tail, utf8str;
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// Flag to properly process Z_BUF_ERROR on testing inflate call
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// when we check that all output data was flushed.
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var allowBufError = false;
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if (this.ended) { return false; }
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_mode = (mode === ~~mode) ? mode : ((mode === true) ? c.Z_FINISH : c.Z_NO_FLUSH);
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// Convert data if needed
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if (typeof data === 'string') {
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// Only binary strings can be decompressed on practice
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strm.input = strings.binstring2buf(data);
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} else if (toString.call(data) === '[object ArrayBuffer]') {
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strm.input = new Uint8Array(data);
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} else {
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strm.input = data;
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}
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strm.next_in = 0;
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strm.avail_in = strm.input.length;
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do {
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if (strm.avail_out === 0) {
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strm.output = new utils.Buf8(chunkSize);
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strm.next_out = 0;
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strm.avail_out = chunkSize;
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}
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status = zlib_inflate.inflate(strm, c.Z_NO_FLUSH); /* no bad return value */
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if (status === c.Z_NEED_DICT && dictionary) {
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status = zlib_inflate.inflateSetDictionary(this.strm, dictionary);
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}
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if (status === c.Z_BUF_ERROR && allowBufError === true) {
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status = c.Z_OK;
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allowBufError = false;
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}
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if (status !== c.Z_STREAM_END && status !== c.Z_OK) {
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this.onEnd(status);
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this.ended = true;
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return false;
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}
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if (strm.next_out) {
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if (strm.avail_out === 0 || status === c.Z_STREAM_END || (strm.avail_in === 0 && (_mode === c.Z_FINISH || _mode === c.Z_SYNC_FLUSH))) {
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if (this.options.to === 'string') {
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next_out_utf8 = strings.utf8border(strm.output, strm.next_out);
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tail = strm.next_out - next_out_utf8;
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utf8str = strings.buf2string(strm.output, next_out_utf8);
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// move tail
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strm.next_out = tail;
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strm.avail_out = chunkSize - tail;
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if (tail) { utils.arraySet(strm.output, strm.output, next_out_utf8, tail, 0); }
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this.onData(utf8str);
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} else {
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this.onData(utils.shrinkBuf(strm.output, strm.next_out));
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}
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}
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}
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// When no more input data, we should check that internal inflate buffers
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// are flushed. The only way to do it when avail_out = 0 - run one more
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// inflate pass. But if output data not exists, inflate return Z_BUF_ERROR.
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// Here we set flag to process this error properly.
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//
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// NOTE. Deflate does not return error in this case and does not needs such
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// logic.
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if (strm.avail_in === 0 && strm.avail_out === 0) {
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allowBufError = true;
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}
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} while ((strm.avail_in > 0 || strm.avail_out === 0) && status !== c.Z_STREAM_END);
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if (status === c.Z_STREAM_END) {
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_mode = c.Z_FINISH;
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}
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// Finalize on the last chunk.
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if (_mode === c.Z_FINISH) {
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status = zlib_inflate.inflateEnd(this.strm);
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this.onEnd(status);
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this.ended = true;
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return status === c.Z_OK;
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}
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// callback interim results if Z_SYNC_FLUSH.
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if (_mode === c.Z_SYNC_FLUSH) {
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this.onEnd(c.Z_OK);
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strm.avail_out = 0;
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return true;
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}
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return true;
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};
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/**
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* Inflate#onData(chunk) -> Void
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* - chunk (Uint8Array|Array|String): output data. Type of array depends
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* on js engine support. When string output requested, each chunk
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* will be string.
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*
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* By default, stores data blocks in `chunks[]` property and glue
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* those in `onEnd`. Override this handler, if you need another behaviour.
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**/
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Inflate.prototype.onData = function (chunk) {
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this.chunks.push(chunk);
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};
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/**
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* Inflate#onEnd(status) -> Void
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* - status (Number): inflate status. 0 (Z_OK) on success,
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* other if not.
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*
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* Called either after you tell inflate that the input stream is
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* complete (Z_FINISH) or should be flushed (Z_SYNC_FLUSH)
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* or if an error happened. By default - join collected chunks,
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* free memory and fill `results` / `err` properties.
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**/
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Inflate.prototype.onEnd = function (status) {
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// On success - join
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if (status === c.Z_OK) {
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if (this.options.to === 'string') {
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// Glue & convert here, until we teach pako to send
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// utf8 aligned strings to onData
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this.result = this.chunks.join('');
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} else {
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this.result = utils.flattenChunks(this.chunks);
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}
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}
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this.chunks = [];
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this.err = status;
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this.msg = this.strm.msg;
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};
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/**
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* inflate(data[, options]) -> Uint8Array|Array|String
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* - data (Uint8Array|Array|String): input data to decompress.
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* - options (Object): zlib inflate options.
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*
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* Decompress `data` with inflate/ungzip and `options`. Autodetect
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* format via wrapper header by default. That's why we don't provide
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* separate `ungzip` method.
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*
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* Supported options are:
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*
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* - windowBits
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*
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* [http://zlib.net/manual.html#Advanced](http://zlib.net/manual.html#Advanced)
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* for more information.
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*
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* Sugar (options):
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*
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* - `raw` (Boolean) - say that we work with raw stream, if you don't wish to specify
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* negative windowBits implicitly.
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* - `to` (String) - if equal to 'string', then result will be converted
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* from utf8 to utf16 (javascript) string. When string output requested,
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* chunk length can differ from `chunkSize`, depending on content.
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*
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*
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* ##### Example:
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*
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* ```javascript
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* var pako = require('pako')
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* , input = pako.deflate([1,2,3,4,5,6,7,8,9])
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* , output;
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*
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* try {
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* output = pako.inflate(input);
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* } catch (err)
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* console.log(err);
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* }
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* ```
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**/
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function inflate(input, options) {
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var inflator = new Inflate(options);
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inflator.push(input, true);
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// That will never happens, if you don't cheat with options :)
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if (inflator.err) { throw inflator.msg || msg[inflator.err]; }
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return inflator.result;
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}
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/**
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* inflateRaw(data[, options]) -> Uint8Array|Array|String
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* - data (Uint8Array|Array|String): input data to decompress.
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* - options (Object): zlib inflate options.
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*
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* The same as [[inflate]], but creates raw data, without wrapper
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* (header and adler32 crc).
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**/
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function inflateRaw(input, options) {
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options = options || {};
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options.raw = true;
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return inflate(input, options);
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}
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/**
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* ungzip(data[, options]) -> Uint8Array|Array|String
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* - data (Uint8Array|Array|String): input data to decompress.
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* - options (Object): zlib inflate options.
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*
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* Just shortcut to [[inflate]], because it autodetects format
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* by header.content. Done for convenience.
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**/
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exports.Inflate = Inflate;
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exports.inflate = inflate;
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exports.inflateRaw = inflateRaw;
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exports.ungzip = inflate;
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