core/deflator.js

   1 /*
   2  * noVNC: HTML5 VNC client
   3  * Copyright (C) 2020 The noVNC Authors
   4  * Licensed under MPL 2.0 (see LICENSE.txt)
   5  *
   6  * See README.md for usage and integration instructions.
   7  */
   8
   9 import { deflateInit, deflate } from "../vendor/pako/lib/zlib/deflate.js";
  10 import { Z_FULL_FLUSH } from "../vendor/pako/lib/zlib/deflate.js";
  11 import ZStream from "../vendor/pako/lib/zlib/zstream.js";
  12
  13 export default class Deflator {
  14     constructor() {
  15         this.strm = new ZStream();
  16         this.chunkSize = 1024 * 10 * 10;
  17         this.outputBuffer = new Uint8Array(this.chunkSize);
  18         this.windowBits = 5;
  19
  20         deflateInit(this.strm, this.windowBits);
  21     }
  22
  23     deflate(inData) {
  24         this.strm.input = inData;
  25         this.strm.avail_in = this.strm.input.length;
  26         this.strm.next_in = 0;
  27         this.strm.output = this.outputBuffer;
  28         this.strm.avail_out = this.chunkSize;
  29         this.strm.next_out = 0;
  30
  31         let lastRet = deflate(this.strm, Z_FULL_FLUSH);
  32         let outData = new Uint8Array(this.strm.output.buffer, 0, this.strm.next_out);
  33
  34         if (lastRet < 0) {
  35             throw new Error("zlib deflate failed");
  36         }
  37
  38         if (this.strm.avail_in > 0) {
  39             // Read chunks until done
  40
  41             let chunks = [outData];
  42             let totalLen = outData.length;
  43             do {
  44                 this.strm.output = new Uint8Array(this.chunkSize);
  45                 this.strm.next_out = 0;
  46                 this.strm.avail_out = this.chunkSize;
  47
  48                 lastRet = deflate(this.strm, Z_FULL_FLUSH);
  49
  50                 if (lastRet < 0) {
  51                     throw new Error("zlib deflate failed");
  52                 }
  53
  54                 let chunk = new Uint8Array(this.strm.output.buffer, 0, this.strm.next_out);
  55                 totalLen += chunk.length;
  56                 chunks.push(chunk);
  57             } while (this.strm.avail_in > 0);
  58
  59             // Combine chunks into a single data
  60
  61             let newData = new Uint8Array(totalLen);
  62             let offset = 0;
  63
  64             for (let i = 0; i < chunks.length; i++) {
  65                 newData.set(chunks[i], offset);
  66                 offset += chunks[i].length;
  67             }
  68
  69             outData = newData;
  70         }
  71
  72         this.strm.input = null;
  73         this.strm.avail_in = 0;
  74         this.strm.next_in = 0;
  75
  76         return outData;
  77     }
  78
  79 }