forked from zhurui/management
184 lines
5.4 KiB
Markdown
184 lines
5.4 KiB
Markdown
pako
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==========================================
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[](https://travis-ci.org/nodeca/pako)
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[](https://www.npmjs.org/package/pako)
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> zlib port to javascript, very fast!
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__Why pako is cool:__
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- Almost as fast in modern JS engines as C implementation (see benchmarks).
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- Works in browsers, you can browserify any separate component.
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- Chunking support for big blobs.
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- Results are binary equal to well known [zlib](http://www.zlib.net/) (now contains ported zlib v1.2.8).
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This project was done to understand how fast JS can be and is it necessary to
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develop native C modules for CPU-intensive tasks. Enjoy the result!
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__Famous projects, using pako:__
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- [browserify](http://browserify.org/) (via [browserify-zlib](https://github.com/devongovett/browserify-zlib))
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- [JSZip](http://stuk.github.io/jszip/)
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- [mincer](https://github.com/nodeca/mincer)
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- [JS-Git](https://github.com/creationix/js-git) and
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[Tedit](https://chrome.google.com/webstore/detail/tedit-development-environ/ooekdijbnbbjdfjocaiflnjgoohnblgf)
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by [@creationix](https://github.com/creationix)
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__Benchmarks:__
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```
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node v0.10.26, 1mb sample:
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deflate-dankogai x 4.73 ops/sec ±0.82% (15 runs sampled)
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deflate-gildas x 4.58 ops/sec ±2.33% (15 runs sampled)
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deflate-imaya x 3.22 ops/sec ±3.95% (12 runs sampled)
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! deflate-pako x 6.99 ops/sec ±0.51% (21 runs sampled)
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deflate-pako-string x 5.89 ops/sec ±0.77% (18 runs sampled)
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deflate-pako-untyped x 4.39 ops/sec ±1.58% (14 runs sampled)
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* deflate-zlib x 14.71 ops/sec ±4.23% (59 runs sampled)
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inflate-dankogai x 32.16 ops/sec ±0.13% (56 runs sampled)
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inflate-imaya x 30.35 ops/sec ±0.92% (53 runs sampled)
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! inflate-pako x 69.89 ops/sec ±1.46% (71 runs sampled)
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inflate-pako-string x 19.22 ops/sec ±1.86% (49 runs sampled)
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inflate-pako-untyped x 17.19 ops/sec ±0.85% (32 runs sampled)
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* inflate-zlib x 70.03 ops/sec ±1.64% (81 runs sampled)
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node v0.11.12, 1mb sample:
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deflate-dankogai x 5.60 ops/sec ±0.49% (17 runs sampled)
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deflate-gildas x 5.06 ops/sec ±6.00% (16 runs sampled)
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deflate-imaya x 3.52 ops/sec ±3.71% (13 runs sampled)
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! deflate-pako x 11.52 ops/sec ±0.22% (32 runs sampled)
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deflate-pako-string x 9.53 ops/sec ±1.12% (27 runs sampled)
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deflate-pako-untyped x 5.44 ops/sec ±0.72% (17 runs sampled)
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* deflate-zlib x 14.05 ops/sec ±3.34% (63 runs sampled)
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inflate-dankogai x 42.19 ops/sec ±0.09% (56 runs sampled)
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inflate-imaya x 79.68 ops/sec ±1.07% (68 runs sampled)
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! inflate-pako x 97.52 ops/sec ±0.83% (80 runs sampled)
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inflate-pako-string x 45.19 ops/sec ±1.69% (57 runs sampled)
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inflate-pako-untyped x 24.35 ops/sec ±2.59% (40 runs sampled)
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* inflate-zlib x 60.32 ops/sec ±1.36% (69 runs sampled)
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```
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zlib's test is partially affected by marshalling (that make sense for inflate only).
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You can change deflate level to 0 in benchmark source, to investigate details.
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For deflate level 6 results can be considered as correct.
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__Install:__
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node.js:
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```
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npm install pako
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```
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browser:
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```
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bower install pako
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```
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Example & API
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-------------
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Full docs - http://nodeca.github.io/pako/
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```javascript
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var pako = require('pako');
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// Deflate
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//
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var input = new Uint8Array();
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//... fill input data here
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var output = pako.deflate(input);
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// Inflate (simple wrapper can throw exception on broken stream)
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//
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var compressed = new Uint8Array();
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//... fill data to uncompress here
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try {
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var result = pako.inflate(compressed);
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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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// Alternate interface for chunking & without exceptions
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//
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var inflator = new pako.Inflate();
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inflator.push(chunk1, false);
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inflator.push(chunk2, false);
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...
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inflator.push(chunkN, true); // true -> last chunk
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if (inflator.err) {
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console.log(inflator.msg);
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}
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var output = inflator.result;
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```
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Sometime you can wish to work with strings. For example, to send
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big objects as json to server. Pako detects input data type. You can
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force output to be string with option `{ to: 'string' }`.
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```javascript
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var pako = require('pako');
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var test = { my: 'super', puper: [456, 567], awesome: 'pako' };
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var binaryString = pako.deflate(JSON.stringify(test), { to: 'string' });
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//
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// Here you can do base64 encode, make xhr requests and so on.
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//
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var restored = JSON.parse(pako.inflate(binaryString, { to: 'string' }));
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```
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Notes
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-----
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Pako does not contain some specific zlib functions:
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- __deflate__ - methods `deflateCopy`, `deflateBound`, `deflateParams`,
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`deflatePending`, `deflatePrime`, `deflateTune`.
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- __inflate__ - methods `inflateCopy`, `inflateMark`,
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`inflatePrime`, `inflateGetDictionary`, `inflateSync`, `inflateSyncPoint`, `inflateUndermine`.
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- High level inflate/deflate wrappers (classes) may not support some flush
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modes. Those should work: Z_NO_FLUSH, Z_FINISH, Z_SYNC_FLUSH.
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Authors
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-------
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- Andrey Tupitsin [@anrd83](https://github.com/andr83)
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- Vitaly Puzrin [@puzrin](https://github.com/puzrin)
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Personal thanks to:
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- Vyacheslav Egorov ([@mraleph](https://github.com/mraleph)) for his awesome
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tutorials about optimising JS code for v8, [IRHydra](http://mrale.ph/irhydra/)
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tool and his advices.
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- David Duponchel ([@dduponchel](https://github.com/dduponchel)) for help with
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testing.
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Original implementation (in C):
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- [zlib](http://zlib.net/) by Jean-loup Gailly and Mark Adler.
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License
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-------
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- MIT - all files, except `/lib/zlib` folder
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- ZLIB - `/lib/zlib` content
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