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Update noVNC to 1.4.0
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commit
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48 changed files with 2545 additions and 504 deletions
141
public/novnc/core/decoders/jpeg.js
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141
public/novnc/core/decoders/jpeg.js
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/*
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* noVNC: HTML5 VNC client
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* Copyright (C) 2019 The noVNC Authors
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* Licensed under MPL 2.0 (see LICENSE.txt)
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*
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* See README.md for usage and integration instructions.
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*
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*/
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export default class JPEGDecoder {
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constructor() {
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// RealVNC will reuse the quantization tables
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// and Huffman tables, so we need to cache them.
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this._quantTables = [];
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this._huffmanTables = [];
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this._cachedQuantTables = [];
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this._cachedHuffmanTables = [];
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this._jpegLength = 0;
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this._segments = [];
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}
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decodeRect(x, y, width, height, sock, display, depth) {
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// A rect of JPEG encodings is simply a JPEG file
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if (!this._parseJPEG(sock.rQslice(0))) {
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return false;
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}
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const data = sock.rQshiftBytes(this._jpegLength);
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if (this._quantTables.length != 0 && this._huffmanTables.length != 0) {
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// If there are quantization tables and Huffman tables in the JPEG
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// image, we can directly render it.
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display.imageRect(x, y, width, height, "image/jpeg", data);
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return true;
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} else {
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// Otherwise we need to insert cached tables.
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const sofIndex = this._segments.findIndex(
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x => x[1] == 0xC0 || x[1] == 0xC2
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);
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if (sofIndex == -1) {
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throw new Error("Illegal JPEG image without SOF");
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}
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let segments = this._segments.slice(0, sofIndex);
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segments = segments.concat(this._quantTables.length ?
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this._quantTables :
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this._cachedQuantTables);
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segments.push(this._segments[sofIndex]);
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segments = segments.concat(this._huffmanTables.length ?
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this._huffmanTables :
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this._cachedHuffmanTables,
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this._segments.slice(sofIndex + 1));
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let length = 0;
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for (let i = 0; i < segments.length; i++) {
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length += segments[i].length;
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}
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const data = new Uint8Array(length);
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length = 0;
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for (let i = 0; i < segments.length; i++) {
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data.set(segments[i], length);
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length += segments[i].length;
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}
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display.imageRect(x, y, width, height, "image/jpeg", data);
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return true;
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}
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}
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_parseJPEG(buffer) {
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if (this._quantTables.length != 0) {
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this._cachedQuantTables = this._quantTables;
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}
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if (this._huffmanTables.length != 0) {
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this._cachedHuffmanTables = this._huffmanTables;
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}
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this._quantTables = [];
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this._huffmanTables = [];
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this._segments = [];
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let i = 0;
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let bufferLength = buffer.length;
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while (true) {
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let j = i;
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if (j + 2 > bufferLength) {
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return false;
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}
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if (buffer[j] != 0xFF) {
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throw new Error("Illegal JPEG marker received (byte: " +
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buffer[j] + ")");
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}
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const type = buffer[j+1];
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j += 2;
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if (type == 0xD9) {
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this._jpegLength = j;
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this._segments.push(buffer.slice(i, j));
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return true;
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} else if (type == 0xDA) {
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// start of scan
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let hasFoundEndOfScan = false;
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for (let k = j + 3; k + 1 < bufferLength; k++) {
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if (buffer[k] == 0xFF && buffer[k+1] != 0x00 &&
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!(buffer[k+1] >= 0xD0 && buffer[k+1] <= 0xD7)) {
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j = k;
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hasFoundEndOfScan = true;
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break;
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}
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}
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if (!hasFoundEndOfScan) {
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return false;
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}
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this._segments.push(buffer.slice(i, j));
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i = j;
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continue;
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} else if (type >= 0xD0 && type < 0xD9 || type == 0x01) {
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// No length after marker
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this._segments.push(buffer.slice(i, j));
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i = j;
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continue;
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}
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if (j + 2 > bufferLength) {
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return false;
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}
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const length = (buffer[j] << 8) + buffer[j+1] - 2;
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if (length < 0) {
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throw new Error("Illegal JPEG length received (length: " +
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length + ")");
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}
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j += 2;
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if (j + length > bufferLength) {
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return false;
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}
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j += length;
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const segment = buffer.slice(i, j);
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if (type == 0xC4) {
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// Huffman tables
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this._huffmanTables.push(segment);
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} else if (type == 0xDB) {
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// Quantization tables
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this._quantTables.push(segment);
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}
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this._segments.push(segment);
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i = j;
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}
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}
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}
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