1 /* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
2 *
3 * This is free software; you can redistribute it and/or modify
4 * it under the terms of the GNU General Public License as published by
5 * the Free Software Foundation; either version 2 of the License, or
6 * (at your option) any later version.
7 *
8 * This software is distributed in the hope that it will be useful,
9 * but WITHOUT ANY WARRANTY; without even the implied warranty of
10 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
11 * GNU General Public License for more details.
12 *
13 * You should have received a copy of the GNU General Public License
14 * along with this software; if not, write to the Free Software
15 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
16 * USA.
17 */
18
19 //
20 // ZRLE decoding function.
21 //
22 // This file is #included after having set the following macro:
23 // BPP - 8, 16 or 32
24
25 namespace rfb {
26
27 // CONCAT2E concatenates its arguments, expanding them if they are macros
28
29 #ifndef CONCAT2E
30 #define CONCAT2(a,b) a##b
31 #define CONCAT2E(a,b) CONCAT2(a,b)
32 #endif
33
34 #ifdef CPIXEL
35 #define PIXEL_T rdr::CONCAT2E(U,BPP)
36 #define READ_PIXEL(is) CONCAT2E(readOpaque,CPIXEL)(is)
37 #define ZRLE_DECODE CONCAT2E(zrleDecode,CPIXEL)
38 #else
39 #define PIXEL_T rdr::CONCAT2E(U,BPP)
40 #define READ_PIXEL(is) is->CONCAT2E(readOpaque,BPP)()
41 #define ZRLE_DECODE CONCAT2E(zrleDecode,BPP)
42 #endif
43
ZRLE_DECODE(const Rect & r,rdr::InStream * is,rdr::ZlibInStream * zis,const PixelFormat & pf,ModifiablePixelBuffer * pb)44 void ZRLE_DECODE (const Rect& r, rdr::InStream* is,
45 rdr::ZlibInStream* zis,
46 const PixelFormat& pf, ModifiablePixelBuffer* pb)
47 {
48 int length = is->readU32();
49 zis->setUnderlying(is, length);
50 Rect t;
51 PIXEL_T buf[64 * 64];
52
53 for (t.tl.y = r.tl.y; t.tl.y < r.br.y; t.tl.y += 64) {
54
55 t.br.y = __rfbmin(r.br.y, t.tl.y + 64);
56
57 for (t.tl.x = r.tl.x; t.tl.x < r.br.x; t.tl.x += 64) {
58
59 t.br.x = __rfbmin(r.br.x, t.tl.x + 64);
60
61 zlibHasData(zis, 1);
62 int mode = zis->readU8();
63 bool rle = mode & 128;
64 int palSize = mode & 127;
65 PIXEL_T palette[128];
66
67 #ifdef CPIXEL
68 zlibHasData(zis, 3 * palSize);
69 #else
70 zlibHasData(zis, BPP/8 * palSize);
71 #endif
72 for (int i = 0; i < palSize; i++) {
73 palette[i] = READ_PIXEL(zis);
74 }
75
76 if (palSize == 1) {
77 PIXEL_T pix = palette[0];
78 pb->fillRect(pf, t, &pix);
79 continue;
80 }
81
82 if (!rle) {
83 if (palSize == 0) {
84
85 // raw
86
87 #ifdef CPIXEL
88 zlibHasData(zis, 3 * t.area());
89 for (PIXEL_T* ptr = buf; ptr < buf+t.area(); ptr++) {
90 *ptr = READ_PIXEL(zis);
91 }
92 #else
93 zlibHasData(zis, BPP/8 * t.area());
94 zis->readBytes(buf, t.area() * (BPP / 8));
95 #endif
96
97 } else {
98
99 // packed pixels
100 int bppp = ((palSize > 16) ? 8 :
101 ((palSize > 4) ? 4 : ((palSize > 2) ? 2 : 1)));
102
103 PIXEL_T* ptr = buf;
104
105 for (int i = 0; i < t.height(); i++) {
106 PIXEL_T* eol = ptr + t.width();
107 rdr::U8 byte = 0;
108 rdr::U8 nbits = 0;
109
110 while (ptr < eol) {
111 if (nbits == 0) {
112 zlibHasData(zis, 1);
113 byte = zis->readU8();
114 nbits = 8;
115 }
116 nbits -= bppp;
117 rdr::U8 index = (byte >> nbits) & ((1 << bppp) - 1) & 127;
118 *ptr++ = palette[index];
119 }
120 }
121 }
122
123 } else {
124
125 if (palSize == 0) {
126
127 // plain RLE
128
129 PIXEL_T* ptr = buf;
130 PIXEL_T* end = ptr + t.area();
131 while (ptr < end) {
132 #ifdef CPIXEL
133 zlibHasData(zis, 3);
134 #else
135 zlibHasData(zis, BPP/8);
136 #endif
137 PIXEL_T pix = READ_PIXEL(zis);
138 int len = 1;
139 int b;
140 do {
141 zlibHasData(zis, 1);
142 b = zis->readU8();
143 len += b;
144 } while (b == 255);
145
146 if (end - ptr < len) {
147 throw Exception ("ZRLE decode error");
148 }
149
150 while (len-- > 0) *ptr++ = pix;
151
152 }
153 } else {
154
155 // palette RLE
156
157 PIXEL_T* ptr = buf;
158 PIXEL_T* end = ptr + t.area();
159 while (ptr < end) {
160 zlibHasData(zis, 1);
161 int index = zis->readU8();
162 int len = 1;
163 if (index & 128) {
164 int b;
165 do {
166 zlibHasData(zis, 1);
167 b = zis->readU8();
168 len += b;
169 } while (b == 255);
170
171 if (end - ptr < len) {
172 throw Exception ("ZRLE decode error");
173 }
174 }
175
176 index &= 127;
177
178 PIXEL_T pix = palette[index];
179
180 while (len-- > 0) *ptr++ = pix;
181 }
182 }
183 }
184
185 pb->imageRect(pf, t, buf);
186 }
187 }
188
189 zis->flushUnderlying();
190 zis->setUnderlying(NULL, 0);
191 }
192
193 #undef ZRLE_DECODE
194 #undef READ_PIXEL
195 #undef PIXEL_T
196 }
197