core/inflator.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 { inflateInit, inflate, inflateReset } from "../vendor/pako/lib/zlib/inflate.js";
  10 import ZStream from "../vendor/pako/lib/zlib/zstream.js";
  11
  12 export default class Inflate {
  13     constructor() {
  14         this.strm = new ZStream();
  15         this.chunkSize = 1024 * 10 * 10;
  16         this.strm.output = new Uint8Array(this.chunkSize);
  17         this.windowBits = 5;
  18
  19         inflateInit(this.strm, this.windowBits);
  20     }
  21
  22     setInput(data) {
  23         if (!data) {
  24             //FIXME: flush remaining data.
  25             this.strm.input = null;
  26             this.strm.avail_in = 0;
  27             this.strm.next_in = 0;
  28         } else {
  29             this.strm.input = data;
  30             this.strm.avail_in = this.strm.input.length;
  31             this.strm.next_in = 0;
  32         }
  33     }
  34
  35     inflate(expected) {
  36         // resize our output buffer if it's too small
  37         // (we could just use multiple chunks, but that would cause an extra
  38         // allocation each time to flatten the chunks)
  39         if (expected > this.chunkSize) {
  40             this.chunkSize = expected;
  41             this.strm.output = new Uint8Array(this.chunkSize);
  42         }
  43
  44         this.strm.next_out = 0;
  45         this.strm.avail_out = this.chunkSize;
  46
  47         let ret = inflate(this.strm, 0); // Flush argument not used.
  48         if (ret < 0) {
  49             throw new Error("zlib inflate failed");
  50         }
  51
  52         if (this.strm.next_out != expected) {
  53             throw new Error("Incomplete zlib block");
  54         }
  55
  56         return new Uint8Array(this.strm.output.buffer, 0, this.strm.next_out);
  57     }
  58
  59     reset() {
  60         inflateReset(this.strm);
  61     }
  62 }