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author | Niko Lehto <nikle@cendio.se> | 2020-02-07 13:23:21 +0100 |
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committer | Niko Lehto <nikle@cendio.se> | 2020-02-17 11:29:29 +0100 |
commit | f52e979082926ab535f36f33e29693988a4bdfef (patch) | |
tree | e6bde4f1d5f4e40b4118947693a03ec97c90bba8 | |
parent | 3b562e8a0f0c15be8d42ce171b296594988d321e (diff) | |
download | novnc-f52e979082926ab535f36f33e29693988a4bdfef.tar.gz |
Add deflator helper class for deflating data
Wraps pako's deflate for easier usage.
-rw-r--r-- | core/deflator.js | 79 | ||||
-rw-r--r-- | tests/test.deflator.js | 80 | ||||
-rw-r--r-- | vendor/pako/lib/zlib/deflate.js | 60 |
3 files changed, 189 insertions, 30 deletions
diff --git a/core/deflator.js b/core/deflator.js new file mode 100644 index 0000000..ad3d0fb --- /dev/null +++ b/core/deflator.js @@ -0,0 +1,79 @@ +/* + * noVNC: HTML5 VNC client + * Copyright (C) 2020 The noVNC Authors + * Licensed under MPL 2.0 (see LICENSE.txt) + * + * See README.md for usage and integration instructions. + */ + +import { deflateInit, deflate } from "../vendor/pako/lib/zlib/deflate.js"; +import { Z_FULL_FLUSH } from "../vendor/pako/lib/zlib/deflate.js"; +import ZStream from "../vendor/pako/lib/zlib/zstream.js"; + +export default class Deflator { + constructor() { + this.strm = new ZStream(); + this.chunkSize = 1024 * 10 * 10; + this.outputBuffer = new Uint8Array(this.chunkSize); + this.windowBits = 5; + + deflateInit(this.strm, this.windowBits); + } + + deflate(inData) { + this.strm.input = inData; + this.strm.avail_in = this.strm.input.length; + this.strm.next_in = 0; + this.strm.output = this.outputBuffer; + this.strm.avail_out = this.chunkSize; + this.strm.next_out = 0; + + let lastRet = deflate(this.strm, Z_FULL_FLUSH); + let outData = new Uint8Array(this.strm.output.buffer, 0, this.strm.next_out); + + if (lastRet < 0) { + throw new Error("zlib deflate failed"); + } + + if (this.strm.avail_in > 0) { + // Read chunks until done + + let chunks = [outData]; + let totalLen = outData.length; + do { + this.strm.output = new Uint8Array(this.chunkSize); + this.strm.next_out = 0; + this.strm.avail_out = this.chunkSize; + + lastRet = deflate(this.strm, Z_FULL_FLUSH); + + if (lastRet < 0) { + throw new Error("zlib deflate failed"); + } + + let chunk = new Uint8Array(this.strm.output.buffer, 0, this.strm.next_out); + totalLen += chunk.length; + chunks.push(chunk); + } while (this.strm.avail_in > 0); + + // Combine chunks into a single data + + let newData = new Uint8Array(totalLen); + let offset = 0; + + for (let i = 0; i < chunks.length; i++) { + newData.set(chunks[i], offset); + offset += chunks[i].length; + } + + outData = newData; + } + + this.strm.input = null; + this.strm.avail_in = 0; + this.strm.next_in = 0; + + return outData; + } + +} diff --git a/tests/test.deflator.js b/tests/test.deflator.js new file mode 100644 index 0000000..2f2fab3 --- /dev/null +++ b/tests/test.deflator.js @@ -0,0 +1,80 @@ +/* eslint-disable no-console */ +const expect = chai.expect; + +import { inflateInit, inflate } from "../vendor/pako/lib/zlib/inflate.js"; +import ZStream from "../vendor/pako/lib/zlib/zstream.js"; +import Deflator from "../core/deflator.js"; + +function _inflator(compText, expected) { + let strm = new ZStream(); + let chunkSize = 1024 * 10 * 10; + strm.output = new Uint8Array(chunkSize); + + inflateInit(strm, 5); + + if (expected > chunkSize) { + chunkSize = expected; + strm.output = new Uint8Array(chunkSize); + } + + strm.input = compText; + strm.avail_in = strm.input.length; + strm.next_in = 0; + + strm.next_out = 0; + strm.avail_out = expected.length; + + let ret = inflate(strm, 0); + + // Check that return code is not an error + expect(ret).to.be.greaterThan(-1); + + return new Uint8Array(strm.output.buffer, 0, strm.next_out); +} + +describe('Deflate data', function () { + + it('should be able to deflate messages', function () { + let deflator = new Deflator(); + + let text = "123asdf"; + let preText = new Uint8Array(text.length); + for (let i = 0; i < preText.length; i++) { + preText[i] = text.charCodeAt(i); + } + + let compText = deflator.deflate(preText); + + let inflatedText = _inflator(compText, text.length); + expect(inflatedText).to.array.equal(preText); + + }); + + it('should be able to deflate large messages', function () { + let deflator = new Deflator(); + + /* Generate a big string with random characters. Used because + repetition of letters might be deflated more effectively than + random ones. */ + let text = ""; + let characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'; + for (let i = 0; i < 300000; i++) { + text += characters.charAt(Math.floor(Math.random() * characters.length)); + } + + let preText = new Uint8Array(text.length); + for (let i = 0; i < preText.length; i++) { + preText[i] = text.charCodeAt(i); + } + + let compText = deflator.deflate(preText); + + //Check that the compressed size is expected size + expect(compText.length).to.be.greaterThan((1024 * 10 * 10) * 2); + + let inflatedText = _inflator(compText, text.length); + + expect(inflatedText).to.array.equal(preText); + + }); +}); diff --git a/vendor/pako/lib/zlib/deflate.js b/vendor/pako/lib/zlib/deflate.js index c51915e..c3a5ba4 100644 --- a/vendor/pako/lib/zlib/deflate.js +++ b/vendor/pako/lib/zlib/deflate.js @@ -9,51 +9,51 @@ import msg from "./messages.js"; /* Allowed flush values; see deflate() and inflate() below for details */ -var Z_NO_FLUSH = 0; -var Z_PARTIAL_FLUSH = 1; -//var Z_SYNC_FLUSH = 2; -var Z_FULL_FLUSH = 3; -var Z_FINISH = 4; -var Z_BLOCK = 5; -//var Z_TREES = 6; +export const Z_NO_FLUSH = 0; +export const Z_PARTIAL_FLUSH = 1; +//export const Z_SYNC_FLUSH = 2; +export const Z_FULL_FLUSH = 3; +export const Z_FINISH = 4; +export const Z_BLOCK = 5; +//export const Z_TREES = 6; /* Return codes for the compression/decompression functions. Negative values * are errors, positive values are used for special but normal events. */ -var Z_OK = 0; -var Z_STREAM_END = 1; -//var Z_NEED_DICT = 2; -//var Z_ERRNO = -1; -var Z_STREAM_ERROR = -2; -var Z_DATA_ERROR = -3; -//var Z_MEM_ERROR = -4; -var Z_BUF_ERROR = -5; -//var Z_VERSION_ERROR = -6; +export const Z_OK = 0; +export const Z_STREAM_END = 1; +//export const Z_NEED_DICT = 2; +//export const Z_ERRNO = -1; +export const Z_STREAM_ERROR = -2; +export const Z_DATA_ERROR = -3; +//export const Z_MEM_ERROR = -4; +export const Z_BUF_ERROR = -5; +//export const Z_VERSION_ERROR = -6; /* compression levels */ -//var Z_NO_COMPRESSION = 0; -//var Z_BEST_SPEED = 1; -//var Z_BEST_COMPRESSION = 9; -var Z_DEFAULT_COMPRESSION = -1; +//export const Z_NO_COMPRESSION = 0; +//export const Z_BEST_SPEED = 1; +//export const Z_BEST_COMPRESSION = 9; +export const Z_DEFAULT_COMPRESSION = -1; -var Z_FILTERED = 1; -var Z_HUFFMAN_ONLY = 2; -var Z_RLE = 3; -var Z_FIXED = 4; -var Z_DEFAULT_STRATEGY = 0; +export const Z_FILTERED = 1; +export const Z_HUFFMAN_ONLY = 2; +export const Z_RLE = 3; +export const Z_FIXED = 4; +export const Z_DEFAULT_STRATEGY = 0; /* Possible values of the data_type field (though see inflate()) */ -//var Z_BINARY = 0; -//var Z_TEXT = 1; -//var Z_ASCII = 1; // = Z_TEXT -var Z_UNKNOWN = 2; +//export const Z_BINARY = 0; +//export const Z_TEXT = 1; +//export const Z_ASCII = 1; // = Z_TEXT +export const Z_UNKNOWN = 2; /* The deflate compression method */ -var Z_DEFLATED = 8; +export const Z_DEFLATED = 8; /*============================================================================*/ |