mirror of
https://github.com/0x5eal/rbxts-pako.git
synced 2025-04-05 19:31:01 +01:00
384 lines
11 KiB
JavaScript
384 lines
11 KiB
JavaScript
'use strict';
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var zlib_inflate = require('./zlib/inflate.js');
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var utils = require('./zlib/utils');
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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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// calculate tail size of utf8 char by current byte value
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function utf8tail(code) {
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return code >= 252 ? 6 : code >= 248 ? 5 : code >= 240 ? 4 : code >= 224 ? 3 : code >= 192 ? 2 : 1;
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}
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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 overriden.
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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).
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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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*
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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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var Inflate = function(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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this.header.name_max = 65536;
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this.header.comm_max = 65536;
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this.header.extra_max = 65536;
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zlib_inflate.inflateGetHeader(this.strm, this.header);
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};
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/**
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* Inflate#push(data[, mode]) -> Boolean
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* - data (Uint8Array|Array|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` meansh 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 flush internal pending buffers and call
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* [[Inflate#onEnd]].
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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 status, _mode;
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var next_out_utf8_index, tail, utf8str;
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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.next_in = utils.binstring2buf(data);
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} else {
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strm.next_in = data;
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}
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strm.next_in_index = 0;
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strm.avail_in = strm.next_in.length;
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do {
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if (strm.avail_out === 0) {
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strm.next_out = new utils.Buf8(chunkSize);
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strm.next_out_index = 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_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_index) {
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if (strm.avail_out === 0 || status === c.Z_STREAM_END || (strm.avail_in === 0 && _mode === c.Z_FINISH)) {
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if (this.to === 'string') {
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// realign size to utf8 char border & move tail to start of buffer
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next_out_utf8_index = strm.next_out_index - 5;
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if (next_out_utf8_index < 0) { next_out_utf8_index = 0; }
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tail = utf8tail(strm.next_out[next_out_utf8_index]);
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while (next_out_utf8_index + tail < strm.next_out_index) {
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next_out_utf8_index += tail;
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tail = utf8tail(strm.next_out[next_out_utf8_index]);
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}
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// shit happened - broken tail. then take it all.
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if (next_out_utf8_index === 0) {
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next_out_utf8_index = strm.next_out_index;
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tail = 0;
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}
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utf8str = utils.buf2string(strm.next_out, next_out_utf8_index);
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// move tail
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strm.next_out_index = tail;
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strm.avail_out = chunkSize - tail;
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if (tail) { utils.arraySet(strm.next_out, strm.next_out, next_out_utf8_index, tail, 0); }
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this.onData(utf8str);
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} else {
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this.onData(utils.shrinkBuf(strm.next_out, strm.next_out_index));
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}
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}
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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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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): ouput 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 once after you tell inflate that input stream complete
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* or error happenned. 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 alligned 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 compress.
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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; }
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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 compress.
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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 compress.
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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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