Mercurial > hg > Applications > TreeVNC

comparison src/main/java/com/glavsoft/rfb/encoding/decoder/TightDecoder.java @ 0:4689cc86d6cb

Find changesets by keywords (author, files, the commit message), revision number or hash, or revset expression.
create TreeViewer2 Repository
author Yu Taninari <you@cr.ie.u-ryukyu.ac.jp>
date Tue, 03 Jul 2012 13:20:49 +0900
parents
children 0c08cdc4b572 17b702648079
comparison
equal deleted inserted replaced
-1:000000000000 0:4689cc86d6cb
1 // Copyright (C) 2010, 2011 GlavSoft LLC.
2 // All rights reserved.
3 //
4 //-------------------------------------------------------------------------
5 // This file is part of the TightVNC software. Please visit our Web site:
6 //
7 // http://www.tightvnc.com/
8 //
9 // This program is free software; you can redistribute it and/or modify
10 // it under the terms of the GNU General Public License as published by
11 // the Free Software Foundation; either version 2 of the License, or
12 // (at your option) any later version.
13 //
14 // This program is distributed in the hope that it will be useful,
15 // but WITHOUT ANY WARRANTY; without even the implied warranty of
16 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 // GNU General Public License for more details.
18 //
19 // You should have received a copy of the GNU General Public License along
20 // with this program; if not, write to the Free Software Foundation, Inc.,
21 // 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
22 //-------------------------------------------------------------------------
23 //
24
25 package com.glavsoft.rfb.encoding.decoder;
26
27 import java.util.logging.Logger;
28 import java.util.zip.DataFormatException;
29 import java.util.zip.Inflater;
30
31 import com.glavsoft.drawing.ColorDecoder;
32 import com.glavsoft.drawing.Renderer;
33 import com.glavsoft.exceptions.TransportException;
34 import com.glavsoft.transport.Reader;
35
36 /**
37 * Tight protocol extention decoder
38 */
39 public class TightDecoder extends Decoder {
40 private static Logger logger = Logger.getLogger("com.glavsoft.rfb.encoding.decoder");
41
42 private static final int FILL_TYPE = 0x08;
43 private static final int JPEG_TYPE = 0x09;
44
45 private static final int FILTER_ID_MASK = 0x40;
46 private static final int STREAM_ID_MASK = 0x30;
47
48 private static final int BASIC_FILTER = 0x00;
49 private static final int PALETTE_FILTER = 0x01;
50 private static final int GRADIENT_FILTER = 0x02;
51 private static final int MIN_SIZE_TO_COMPRESS = 12;
52
53 static final int DECODERS_NUM = 4;
54 Inflater[] decoders;
55
56 private int decoderId;
57
58 final static int tightZlibBufferSize = 512;
59
60 public TightDecoder() {
61 reset();
62 }
63
64 @Override
65 public void decode(Reader reader, Renderer renderer,
66 FramebufferUpdateRectangle rect) throws TransportException {
67 int bytesPerPixel = renderer.getBytesPerPixelSignificant();
68
69 /**
70 * bits
71 * 7 - FILL or JPEG type
72 * 6 - filter presence flag
73 * 5, 4 - decoder to use when Basic type (bit 7 not set)
74 * or
75 * 4 - JPEG type when set bit 7
76 * 3 - reset decoder #3
77 * 2 - reset decoder #2
78 * 1 - reset decoder #1
79 * 0 - reset decoder #0
80 */
81 int compControl = reader.readUInt8();
82 resetDecoders(compControl);
83
84 int compType = compControl >> 4 & 0x0F;
85 switch (compType) {
86 case FILL_TYPE:
87 int color = renderer.readTightPixelColor(reader);
88 renderer.fillRect(color, rect);
89 break;
90 case JPEG_TYPE:
91 if (bytesPerPixel != 3) {
92 // throw new EncodingException(
93 // "Tight doesn't support JPEG subencoding while depth not equal to 24bpp is used");
94 }
95 processJpegType(reader, renderer, rect);
96 break;
97 default:
98 if (compType > JPEG_TYPE) {
99 // throw new EncodingException(
100 // "Compression control byte is incorrect!");
101 } else {
102 processBasicType(compControl, reader, renderer, rect);
103 }
104 }
105 }
106
107 private void processBasicType(int compControl, Reader reader,
108 Renderer renderer, FramebufferUpdateRectangle rect) throws TransportException {
109 decoderId = (compControl & STREAM_ID_MASK) >> 4;
110
111 int filterId = 0;
112 if ((compControl & FILTER_ID_MASK) > 0) { // filter byte presence
113 filterId = reader.readUInt8();
114 }
115 int bytesPerCPixel = renderer.getBytesPerPixelSignificant();
116 int lengthCurrentbpp = bytesPerCPixel * rect.width * rect.height;
117 byte [] buffer;
118 switch (filterId) {
119 case BASIC_FILTER:
120 buffer = readTightData(lengthCurrentbpp, reader);
121 renderer.drawTightBytes(buffer, 0, rect.x, rect.y, rect.width, rect.height);
122 break;
123 case PALETTE_FILTER:
124 int paletteSize = reader.readUInt8() + 1;
125 int[] palette = readPalette(paletteSize, reader, renderer);
126 int dataLength = paletteSize == 2 ?
127 rect.height * ((rect.width + 7) / 8) :
128 rect.width * rect.height;
129 buffer = readTightData(dataLength, reader);
130 renderer.drawBytesWithPalette(buffer, rect, palette);
131 break;
132 case GRADIENT_FILTER:
133 /*
134 * The "gradient" filter pre-processes pixel data with a simple algorithm
135 * which converts each color component to a difference between a "predicted"
136 * intensity and the actual intensity. Such a technique does not affect
137 * uncompressed data size, but helps to compress photo-like images better.
138 * Pseudo-code for converting intensities to differences is the following:
139 *
140 * P[i,j] := V[i-1,j] + V[i,j-1] - V[i-1,j-1];
141 * if (P[i,j] < 0) then P[i,j] := 0;
142 * if (P[i,j] > MAX) then P[i,j] := MAX;
143 * D[i,j] := V[i,j] - P[i,j];
144 *
145 * Here V[i,j] is the intensity of a color component for a pixel at
146 * coordinates (i,j). MAX is the maximum value of intensity for a color
147 * component.*/
148 buffer = readTightData(bytesPerCPixel * rect.width * rect.height, reader);
149 byte [][] opRows = new byte[2][rect.width * 3 + 3];
150 int opRowIndex = 0;
151 byte [] components = new byte[3];
152 int pixelOffset = 0;
153 ColorDecoder colorDecoder = renderer.getColorDecoder();
154 for (int i = 0; i < rect.height; ++i) {
155 // exchange thisRow and prevRow:
156 byte [] thisRow = opRows[opRowIndex];
157 byte [] prevRow = opRows[opRowIndex = (opRowIndex + 1) % 2];
158 for (int j = 3; j < rect.width * 3 + 3; j += 3) {
159 colorDecoder.fillRawComponents(components, buffer, pixelOffset);
160 pixelOffset += bytesPerCPixel;
161 int
162 d = (0xff & prevRow[j + 0]) + // "upper" pixel (from prev row)
163 (0xff & thisRow[j + 0 - 3]) - // prev pixel
164 (0xff & prevRow[j + 0 - 3]); // "diagonal" prev pixel
165 thisRow[j + 0] = (byte) (components[0] + (d < 0 ? 0 : d > colorDecoder.redMax ? colorDecoder.redMax: d) & colorDecoder.redMax);
166 d = (0xff & prevRow[j + 1]) +
167 (0xff & thisRow[j + 1 - 3]) -
168 (0xff & prevRow[j + 1 - 3]);
169 thisRow[j + 1] = (byte) (components[1] + (d < 0 ? 0 : d > colorDecoder.greenMax ? colorDecoder.greenMax: d) & colorDecoder.greenMax);
170 d = (0xff & prevRow[j + 2]) +
171 (0xff & thisRow[j + 2 - 3]) -
172 (0xff & prevRow[j + 2 - 3]);
173 thisRow[j + 2] = (byte) (components[2] + (d < 0 ? 0 : d > colorDecoder.blueMax ? colorDecoder.blueMax: d) & colorDecoder.blueMax);
174 }
175 renderer.drawUncaliberedRGBLine(thisRow, rect.x, rect.y + i, rect.width);
176 }
177
178 break;
179 default:
180 break;
181 }
182 }
183
184 /**
185 * Read palette from reader
186 */
187 private int[] readPalette(int paletteSize, Reader reader, Renderer renderer) throws TransportException {
188 /**
189 * When bytesPerPixel == 1 && paletteSize == 2 read 2 bytes of palette
190 * When bytesPerPixel == 1 && paletteSize != 2 - error
191 * When bytesPerPixel == 3 (4) read (paletteSize * 3) bytes of palette
192 * so use renderer.readPixelColor
193 */
194 int[] palette = new int[paletteSize];
195 for (int i = 0; i < palette.length; ++i) {
196 palette[i] = renderer.readTightPixelColor(reader);
197 }
198 return palette;
199 }
200
201 /**
202 * Reads compressed (expected length >= MIN_SIZE_TO_COMPRESS) or
203 * uncompressed data. When compressed decompresses it.
204 *
205 * @param expectedLength expected data length in bytes
206 * @param reader
207 * @return result data
208 * @throws TransportException
209 */
210 private byte[] readTightData(int expectedLength, Reader reader) throws TransportException {
211 if (expectedLength < MIN_SIZE_TO_COMPRESS) {
212 byte [] buffer = ByteBuffer.getInstance().getBuffer(expectedLength);
213 reader.readBytes(buffer, 0, expectedLength);
214 return buffer;
215 } else
216 return readCompressedData(expectedLength, reader);
217 }
218
219 /**
220 * Reads compressed data length, then read compressed data into rawBuffer
221 * and decompress data with expected length == length
222 *
223 * Note: returned data contains not only decompressed data but raw data at array tail
224 * which need to be ignored. Use only first expectedLength bytes.
225 *
226 * @param expectedLength expected data length
227 * @param reader
228 * @return decompressed data (length == expectedLength) / + followed raw data (ignore, please)
229 * @throws TransportException
230 */
231 private byte[] readCompressedData(int expectedLength, Reader reader) throws TransportException {
232 int rawDataLength = readCompactSize(reader);
233
234 byte [] buffer = ByteBuffer.getInstance().getBuffer(expectedLength + rawDataLength);
235 // read compressed (raw) data behind space allocated for decompressed data
236 reader.readBytes(buffer, expectedLength, rawDataLength);
237 if (null == decoders[decoderId]) {
238 decoders[decoderId] = new Inflater();
239 }
240 Inflater decoder = decoders[decoderId];
241 decoder.setInput(buffer, expectedLength, rawDataLength);
242 try {
243 decoder.inflate(buffer, 0, expectedLength);
244 } catch (DataFormatException e) {
245 logger.throwing("TightDecoder", "readCompressedData", e);
246 throw new TransportException("cannot inflate tight compressed data", e);
247 }
248 return buffer;
249 }
250
251 private void processJpegType(Reader reader, Renderer renderer,
252 FramebufferUpdateRectangle rect) throws TransportException {
253 int jpegBufferLength = readCompactSize(reader);
254 byte [] bytes = ByteBuffer.getInstance().getBuffer(jpegBufferLength);
255 reader.readBytes(bytes, 0, jpegBufferLength);
256 renderer.drawJpegImage(bytes, 0, jpegBufferLength, rect);
257 }
258
259 /**
260 * Read an integer from reader in compact representation (from 1 to 3 bytes).
261 * Highest bit of read byte set to 1 means next byte contains data.
262 * Lower 7 bit of each byte contains significant data. Max bytes = 3.
263 * Less significant bytes first order.
264 *
265 * @param reader
266 * @return int value
267 * @throws TransportException
268 */
269 private int readCompactSize(Reader reader) throws TransportException {
270 int b = reader.readUInt8();
271 int size = b & 0x7F;
272 if ((b & 0x80) != 0) {
273 b = reader.readUInt8();
274 size += (b & 0x7F) << 7;
275 if ((b & 0x80) != 0) {
276 size += reader.readUInt8() << 14;
277 }
278 }
279 return size;
280 }
281
282 /**
283 * Flush (reset) zlib decoders when bits 3, 2, 1, 0 of compControl is set
284 * @param compControl
285 */
286 private void resetDecoders(int compControl) {
287 for (int i=0; i < DECODERS_NUM; ++i) {
288 if ((compControl & 1) != 0 && decoders[i] != null) {
289 decoders[i].reset();
290 }
291 compControl >>= 1;
292 }
293
294 }
295
296 @Override
297 public void reset() {
298 decoders = new Inflater[DECODERS_NUM];
299 }
300
301 }