Current File : //lib/node_modules/pm2/node_modules/pako/lib/deflate.js
'use strict';
var zlib_deflate = require('./zlib/deflate');
var utils = require('./utils/common');
var strings = require('./utils/strings');
var msg = require('./zlib/messages');
var ZStream = require('./zlib/zstream');
var toString = Object.prototype.toString;
/* Public constants ==========================================================*/
/* ===========================================================================*/
var Z_NO_FLUSH = 0;
var Z_FINISH = 4;
var Z_OK = 0;
var Z_STREAM_END = 1;
var Z_SYNC_FLUSH = 2;
var Z_DEFAULT_COMPRESSION = -1;
var Z_DEFAULT_STRATEGY = 0;
var Z_DEFLATED = 8;
/* ===========================================================================*/
/**
* class Deflate
*
* Generic JS-style wrapper for zlib calls. If you don't need
* streaming behaviour - use more simple functions: [[deflate]],
* [[deflateRaw]] and [[gzip]].
**/
/* internal
* Deflate.chunks -> Array
*
* Chunks of output data, if [[Deflate#onData]] not overriden.
**/
/**
* Deflate.result -> Uint8Array|Array
*
* Compressed result, generated by default [[Deflate#onData]]
* and [[Deflate#onEnd]] handlers. Filled after you push last chunk
* (call [[Deflate#push]] with `Z_FINISH` / `true` param) or if you
* push a chunk with explicit flush (call [[Deflate#push]] with
* `Z_SYNC_FLUSH` param).
**/
/**
* Deflate.err -> Number
*
* Error code after deflate finished. 0 (Z_OK) on success.
* You will not need it in real life, because deflate errors
* are possible only on wrong options or bad `onData` / `onEnd`
* custom handlers.
**/
/**
* Deflate.msg -> String
*
* Error message, if [[Deflate.err]] != 0
**/
/**
* new Deflate(options)
* - options (Object): zlib deflate options.
*
* Creates new deflator instance with specified params. Throws exception
* on bad params. Supported options:
*
* - `level`
* - `windowBits`
* - `memLevel`
* - `strategy`
* - `dictionary`
*
* [http://zlib.net/manual.html#Advanced](http://zlib.net/manual.html#Advanced)
* for more information on these.
*
* Additional options, for internal needs:
*
* - `chunkSize` - size of generated data chunks (16K by default)
* - `raw` (Boolean) - do raw deflate
* - `gzip` (Boolean) - create gzip wrapper
* - `to` (String) - if equal to 'string', then result will be "binary string"
* (each char code [0..255])
* - `header` (Object) - custom header for gzip
* - `text` (Boolean) - true if compressed data believed to be text
* - `time` (Number) - modification time, unix timestamp
* - `os` (Number) - operation system code
* - `extra` (Array) - array of bytes with extra data (max 65536)
* - `name` (String) - file name (binary string)
* - `comment` (String) - comment (binary string)
* - `hcrc` (Boolean) - true if header crc should be added
*
* ##### Example:
*
* ```javascript
* var pako = require('pako')
* , chunk1 = Uint8Array([1,2,3,4,5,6,7,8,9])
* , chunk2 = Uint8Array([10,11,12,13,14,15,16,17,18,19]);
*
* var deflate = new pako.Deflate({ level: 3});
*
* deflate.push(chunk1, false);
* deflate.push(chunk2, true); // true -> last chunk
*
* if (deflate.err) { throw new Error(deflate.err); }
*
* console.log(deflate.result);
* ```
**/
function Deflate(options) {
if (!(this instanceof Deflate)) return new Deflate(options);
this.options = utils.assign({
level: Z_DEFAULT_COMPRESSION,
method: Z_DEFLATED,
chunkSize: 16384,
windowBits: 15,
memLevel: 8,
strategy: Z_DEFAULT_STRATEGY,
to: ''
}, options || {});
var opt = this.options;
if (opt.raw && (opt.windowBits > 0)) {
opt.windowBits = -opt.windowBits;
}
else if (opt.gzip && (opt.windowBits > 0) && (opt.windowBits < 16)) {
opt.windowBits += 16;
}
this.err = 0; // error code, if happens (0 = Z_OK)
this.msg = ''; // error message
this.ended = false; // used to avoid multiple onEnd() calls
this.chunks = []; // chunks of compressed data
this.strm = new ZStream();
this.strm.avail_out = 0;
var status = zlib_deflate.deflateInit2(
this.strm,
opt.level,
opt.method,
opt.windowBits,
opt.memLevel,
opt.strategy
);
if (status !== Z_OK) {
throw new Error(msg[status]);
}
if (opt.header) {
zlib_deflate.deflateSetHeader(this.strm, opt.header);
}
if (opt.dictionary) {
var dict;
// Convert data if needed
if (typeof opt.dictionary === 'string') {
// If we need to compress text, change encoding to utf8.
dict = strings.string2buf(opt.dictionary);
} else if (toString.call(opt.dictionary) === '[object ArrayBuffer]') {
dict = new Uint8Array(opt.dictionary);
} else {
dict = opt.dictionary;
}
status = zlib_deflate.deflateSetDictionary(this.strm, dict);
if (status !== Z_OK) {
throw new Error(msg[status]);
}
this._dict_set = true;
}
}
/**
* Deflate#push(data[, mode]) -> Boolean
* - data (Uint8Array|Array|ArrayBuffer|String): input data. Strings will be
* converted to utf8 byte sequence.
* - mode (Number|Boolean): 0..6 for corresponding Z_NO_FLUSH..Z_TREE modes.
* See constants. Skipped or `false` means Z_NO_FLUSH, `true` meansh Z_FINISH.
*
* Sends input data to deflate pipe, generating [[Deflate#onData]] calls with
* new compressed chunks. Returns `true` on success. The last data block must have
* mode Z_FINISH (or `true`). That will flush internal pending buffers and call
* [[Deflate#onEnd]]. For interim explicit flushes (without ending the stream) you
* can use mode Z_SYNC_FLUSH, keeping the compression context.
*
* On fail call [[Deflate#onEnd]] with error code and return false.
*
* We strongly recommend to use `Uint8Array` on input for best speed (output
* array format is detected automatically). Also, don't skip last param and always
* use the same type in your code (boolean or number). That will improve JS speed.
*
* For regular `Array`-s make sure all elements are [0..255].
*
* ##### Example
*
* ```javascript
* push(chunk, false); // push one of data chunks
* ...
* push(chunk, true); // push last chunk
* ```
**/
Deflate.prototype.push = function (data, mode) {
var strm = this.strm;
var chunkSize = this.options.chunkSize;
var status, _mode;
if (this.ended) { return false; }
_mode = (mode === ~~mode) ? mode : ((mode === true) ? Z_FINISH : Z_NO_FLUSH);
// Convert data if needed
if (typeof data === 'string') {
// If we need to compress text, change encoding to utf8.
strm.input = strings.string2buf(data);
} else if (toString.call(data) === '[object ArrayBuffer]') {
strm.input = new Uint8Array(data);
} else {
strm.input = data;
}
strm.next_in = 0;
strm.avail_in = strm.input.length;
do {
if (strm.avail_out === 0) {
strm.output = new utils.Buf8(chunkSize);
strm.next_out = 0;
strm.avail_out = chunkSize;
}
status = zlib_deflate.deflate(strm, _mode); /* no bad return value */
if (status !== Z_STREAM_END && status !== Z_OK) {
this.onEnd(status);
this.ended = true;
return false;
}
if (strm.avail_out === 0 || (strm.avail_in === 0 && (_mode === Z_FINISH || _mode === Z_SYNC_FLUSH))) {
if (this.options.to === 'string') {
this.onData(strings.buf2binstring(utils.shrinkBuf(strm.output, strm.next_out)));
} else {
this.onData(utils.shrinkBuf(strm.output, strm.next_out));
}
}
} while ((strm.avail_in > 0 || strm.avail_out === 0) && status !== Z_STREAM_END);
// Finalize on the last chunk.
if (_mode === Z_FINISH) {
status = zlib_deflate.deflateEnd(this.strm);
this.onEnd(status);
this.ended = true;
return status === Z_OK;
}
// callback interim results if Z_SYNC_FLUSH.
if (_mode === Z_SYNC_FLUSH) {
this.onEnd(Z_OK);
strm.avail_out = 0;
return true;
}
return true;
};
/**
* Deflate#onData(chunk) -> Void
* - chunk (Uint8Array|Array|String): ouput data. Type of array depends
* on js engine support. When string output requested, each chunk
* will be string.
*
* By default, stores data blocks in `chunks[]` property and glue
* those in `onEnd`. Override this handler, if you need another behaviour.
**/
Deflate.prototype.onData = function (chunk) {
this.chunks.push(chunk);
};
/**
* Deflate#onEnd(status) -> Void
* - status (Number): deflate status. 0 (Z_OK) on success,
* other if not.
*
* Called once after you tell deflate that the input stream is
* complete (Z_FINISH) or should be flushed (Z_SYNC_FLUSH)
* or if an error happened. By default - join collected chunks,
* free memory and fill `results` / `err` properties.
**/
Deflate.prototype.onEnd = function (status) {
// On success - join
if (status === Z_OK) {
if (this.options.to === 'string') {
this.result = this.chunks.join('');
} else {
this.result = utils.flattenChunks(this.chunks);
}
}
this.chunks = [];
this.err = status;
this.msg = this.strm.msg;
};
/**
* deflate(data[, options]) -> Uint8Array|Array|String
* - data (Uint8Array|Array|String): input data to compress.
* - options (Object): zlib deflate options.
*
* Compress `data` with deflate algorithm and `options`.
*
* Supported options are:
*
* - level
* - windowBits
* - memLevel
* - strategy
* - dictionary
*
* [http://zlib.net/manual.html#Advanced](http://zlib.net/manual.html#Advanced)
* for more information on these.
*
* Sugar (options):
*
* - `raw` (Boolean) - say that we work with raw stream, if you don't wish to specify
* negative windowBits implicitly.
* - `to` (String) - if equal to 'string', then result will be "binary string"
* (each char code [0..255])
*
* ##### Example:
*
* ```javascript
* var pako = require('pako')
* , data = Uint8Array([1,2,3,4,5,6,7,8,9]);
*
* console.log(pako.deflate(data));
* ```
**/
function deflate(input, options) {
var deflator = new Deflate(options);
deflator.push(input, true);
// That will never happens, if you don't cheat with options :)
if (deflator.err) { throw deflator.msg; }
return deflator.result;
}
/**
* deflateRaw(data[, options]) -> Uint8Array|Array|String
* - data (Uint8Array|Array|String): input data to compress.
* - options (Object): zlib deflate options.
*
* The same as [[deflate]], but creates raw data, without wrapper
* (header and adler32 crc).
**/
function deflateRaw(input, options) {
options = options || {};
options.raw = true;
return deflate(input, options);
}
/**
* gzip(data[, options]) -> Uint8Array|Array|String
* - data (Uint8Array|Array|String): input data to compress.
* - options (Object): zlib deflate options.
*
* The same as [[deflate]], but create gzip wrapper instead of
* deflate one.
**/
function gzip(input, options) {
options = options || {};
options.gzip = true;
return deflate(input, options);
}
exports.Deflate = Deflate;
exports.deflate = deflate;
exports.deflateRaw = deflateRaw;
exports.gzip = gzip;
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