core/decoders/tight.js

   1 /*
   2  * noVNC: HTML5 VNC client
   3  * Copyright (C) 2019 The noVNC Authors
   4  * (c) 2012 Michael Tinglof, Joe Balaz, Les Piech (Mercuri.ca)
   5  * Licensed under MPL 2.0 (see LICENSE.txt)
   6  *
   7  * See README.md for usage and integration instructions.
   8  *
   9  */
  10
  11 import * as Log from '../util/logging.js';
  12 import Inflator from "../inflator.js";
  13
  14 export default class TightDecoder {
  15     constructor() {
  16         this._ctl = null;
  17         this._filter = null;
  18         this._numColors = 0;
  19         this._palette = new Uint8Array(1024);  // 256 * 4 (max palette size * max bytes-per-pixel)
  20         this._len = 0;
  21
  22         this._zlibs = [];
  23         for (let i = 0; i < 4; i++) {
  24             this._zlibs[i] = new Inflator();
  25         }
  26     }
  27
  28     decodeRect(x, y, width, height, sock, display, depth) {
  29         if (this._ctl === null) {
  30             if (sock.rQwait("TIGHT compression-control", 1)) {
  31                 return false;
  32             }
  33
  34             this._ctl = sock.rQshift8();
  35
  36             // Reset streams if the server requests it
  37             for (let i = 0; i < 4; i++) {
  38                 if ((this._ctl >> i) & 1) {
  39                     this._zlibs[i].reset();
  40                     Log.Info("Reset zlib stream " + i);
  41                 }
  42             }
  43
  44             // Figure out filter
  45             this._ctl = this._ctl >> 4;
  46         }
  47
  48         let ret;
  49
  50         if (this._ctl === 0x08) {
  51             ret = this._fillRect(x, y, width, height,
  52                                  sock, display, depth);
  53         } else if (this._ctl === 0x09) {
  54             ret = this._jpegRect(x, y, width, height,
  55                                  sock, display, depth);
  56         } else if (this._ctl === 0x0A) {
  57             ret = this._pngRect(x, y, width, height,
  58                                 sock, display, depth);
  59         } else if ((this._ctl & 0x80) == 0) {
  60             ret = this._basicRect(this._ctl, x, y, width, height,
  61                                   sock, display, depth);
  62         } else {
  63             throw new Error("Illegal tight compression received (ctl: " +
  64                                    this._ctl + ")");
  65         }
  66
  67         if (ret) {
  68             this._ctl = null;
  69         }
  70
  71         return ret;
  72     }
  73
  74     _fillRect(x, y, width, height, sock, display, depth) {
  75         if (sock.rQwait("TIGHT", 3)) {
  76             return false;
  77         }
  78
  79         const rQi = sock.rQi;
  80         const rQ = sock.rQ;
  81
  82         display.fillRect(x, y, width, height,
  83                          [rQ[rQi + 2], rQ[rQi + 1], rQ[rQi]], false);
  84         sock.rQskipBytes(3);
  85
  86         return true;
  87     }
  88
  89     _jpegRect(x, y, width, height, sock, display, depth) {
  90         let data = this._readData(sock);
  91         if (data === null) {
  92             return false;
  93         }
  94
  95         display.imageRect(x, y, width, height, "image/jpeg", data);
  96
  97         return true;
  98     }
  99
 100     _pngRect(x, y, width, height, sock, display, depth) {
 101         throw new Error("PNG received in standard Tight rect");
 102     }
 103
 104     _basicRect(ctl, x, y, width, height, sock, display, depth) {
 105         if (this._filter === null) {
 106             if (ctl & 0x4) {
 107                 if (sock.rQwait("TIGHT", 1)) {
 108                     return false;
 109                 }
 110
 111                 this._filter = sock.rQshift8();
 112             } else {
 113                 // Implicit CopyFilter
 114                 this._filter = 0;
 115             }
 116         }
 117
 118         let streamId = ctl & 0x3;
 119
 120         let ret;
 121
 122         switch (this._filter) {
 123             case 0: // CopyFilter
 124                 ret = this._copyFilter(streamId, x, y, width, height,
 125                                        sock, display, depth);
 126                 break;
 127             case 1: // PaletteFilter
 128                 ret = this._paletteFilter(streamId, x, y, width, height,
 129                                           sock, display, depth);
 130                 break;
 131             case 2: // GradientFilter
 132                 ret = this._gradientFilter(streamId, x, y, width, height,
 133                                            sock, display, depth);
 134                 break;
 135             default:
 136                 throw new Error("Illegal tight filter received (ctl: " +
 137                                        this._filter + ")");
 138         }
 139
 140         if (ret) {
 141             this._filter = null;
 142         }
 143
 144         return ret;
 145     }
 146
 147     _copyFilter(streamId, x, y, width, height, sock, display, depth) {
 148         const uncompressedSize = width * height * 3;
 149         let data;
 150
 151         if (uncompressedSize < 12) {
 152             if (sock.rQwait("TIGHT", uncompressedSize)) {
 153                 return false;
 154             }
 155
 156             data = sock.rQshiftBytes(uncompressedSize);
 157         } else {
 158             data = this._readData(sock);
 159             if (data === null) {
 160                 return false;
 161             }
 162
 163             data = this._zlibs[streamId].inflate(data, true, uncompressedSize);
 164             if (data.length != uncompressedSize) {
 165                 throw new Error("Incomplete zlib block");
 166             }
 167         }
 168
 169         display.blitRgbImage(x, y, width, height, data, 0, false);
 170
 171         return true;
 172     }
 173
 174     _paletteFilter(streamId, x, y, width, height, sock, display, depth) {
 175         if (this._numColors === 0) {
 176             if (sock.rQwait("TIGHT palette", 1)) {
 177                 return false;
 178             }
 179
 180             const numColors = sock.rQpeek8() + 1;
 181             const paletteSize = numColors * 3;
 182
 183             if (sock.rQwait("TIGHT palette", 1 + paletteSize)) {
 184                 return false;
 185             }
 186
 187             this._numColors = numColors;
 188             sock.rQskipBytes(1);
 189
 190             sock.rQshiftTo(this._palette, paletteSize);
 191         }
 192
 193         const bpp = (this._numColors <= 2) ? 1 : 8;
 194         const rowSize = Math.floor((width * bpp + 7) / 8);
 195         const uncompressedSize = rowSize * height;
 196
 197         let data;
 198
 199         if (uncompressedSize < 12) {
 200             if (sock.rQwait("TIGHT", uncompressedSize)) {
 201                 return false;
 202             }
 203
 204             data = sock.rQshiftBytes(uncompressedSize);
 205         } else {
 206             data = this._readData(sock);
 207             if (data === null) {
 208                 return false;
 209             }
 210
 211             data = this._zlibs[streamId].inflate(data, true, uncompressedSize);
 212             if (data.length != uncompressedSize) {
 213                 throw new Error("Incomplete zlib block");
 214             }
 215         }
 216
 217         // Convert indexed (palette based) image data to RGB
 218         if (this._numColors == 2) {
 219             this._monoRect(x, y, width, height, data, this._palette, display);
 220         } else {
 221             this._paletteRect(x, y, width, height, data, this._palette, display);
 222         }
 223
 224         this._numColors = 0;
 225
 226         return true;
 227     }
 228
 229     _monoRect(x, y, width, height, data, palette, display) {
 230         // Convert indexed (palette based) image data to RGB
 231         // TODO: reduce number of calculations inside loop
 232         const dest = this._getScratchBuffer(width * height * 4);
 233         const w = Math.floor((width + 7) / 8);
 234         const w1 = Math.floor(width / 8);
 235
 236         for (let y = 0; y < height; y++) {
 237             let dp, sp, x;
 238             for (x = 0; x < w1; x++) {
 239                 for (let b = 7; b >= 0; b--) {
 240                     dp = (y * width + x * 8 + 7 - b) * 4;
 241                     sp = (data[y * w + x] >> b & 1) * 3;
 242                     dest[dp] = palette[sp];
 243                     dest[dp + 1] = palette[sp + 1];
 244                     dest[dp + 2] = palette[sp + 2];
 245                     dest[dp + 3] = 255;
 246                 }
 247             }
 248
 249             for (let b = 7; b >= 8 - width % 8; b--) {
 250                 dp = (y * width + x * 8 + 7 - b) * 4;
 251                 sp = (data[y * w + x] >> b & 1) * 3;
 252                 dest[dp] = palette[sp];
 253                 dest[dp + 1] = palette[sp + 1];
 254                 dest[dp + 2] = palette[sp + 2];
 255                 dest[dp + 3] = 255;
 256             }
 257         }
 258
 259         display.blitRgbxImage(x, y, width, height, dest, 0, false);
 260     }
 261
 262     _paletteRect(x, y, width, height, data, palette, display) {
 263         // Convert indexed (palette based) image data to RGB
 264         const dest = this._getScratchBuffer(width * height * 4);
 265         const total = width * height * 4;
 266         for (let i = 0, j = 0; i < total; i += 4, j++) {
 267             const sp = data[j] * 3;
 268             dest[i] = palette[sp];
 269             dest[i + 1] = palette[sp + 1];
 270             dest[i + 2] = palette[sp + 2];
 271             dest[i + 3] = 255;
 272         }
 273
 274         display.blitRgbxImage(x, y, width, height, dest, 0, false);
 275     }
 276
 277     _gradientFilter(streamId, x, y, width, height, sock, display, depth) {
 278         throw new Error("Gradient filter not implemented");
 279     }
 280
 281     _readData(sock) {
 282         if (this._len === 0) {
 283             if (sock.rQwait("TIGHT", 3)) {
 284                 return null;
 285             }
 286
 287             let byte;
 288
 289             byte = sock.rQshift8();
 290             this._len = byte & 0x7f;
 291             if (byte & 0x80) {
 292                 byte = sock.rQshift8();
 293                 this._len |= (byte & 0x7f) << 7;
 294                 if (byte & 0x80) {
 295                     byte = sock.rQshift8();
 296                     this._len |= byte << 14;
 297                 }
 298             }
 299         }
 300
 301         if (sock.rQwait("TIGHT", this._len)) {
 302             return null;
 303         }
 304
 305         let data = sock.rQshiftBytes(this._len);
 306         this._len = 0;
 307
 308         return data;
 309     }
 310
 311     _getScratchBuffer(size) {
 312         if (!this._scratchBuffer || (this._scratchBuffer.length < size)) {
 313             this._scratchBuffer = new Uint8Array(size);
 314         }
 315         return this._scratchBuffer;
 316     }
 317 }