|
0
|
1 package treeVnc;
|
|
|
2 /* Copyright (C) 2002-2005 RealVNC Ltd. All Rights Reserved.
|
|
|
3 *
|
|
|
4 * This is free software; you can redistribute it and/or modify
|
|
|
5 * it under the terms of the GNU General Public License as published by
|
|
|
6 * the Free Software Foundation; either version 2 of the License, or
|
|
|
7 * (at your option) any later version.
|
|
|
8 *
|
|
|
9 * This software is distributed in the hope that it will be useful,
|
|
|
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
|
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
|
12 * GNU General Public License for more details.
|
|
|
13 *
|
|
|
14 * You should have received a copy of the GNU General Public License
|
|
|
15 * along with this software; if not, write to the Free Software
|
|
|
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
|
|
|
17 * USA.
|
|
|
18 */
|
|
|
19
|
|
|
20 //
|
|
|
21 // rdr::InStream marshalls data from a buffer stored in RDR (RFB Data
|
|
|
22 // Representation).
|
|
|
23 //
|
|
|
24
|
|
|
25 abstract public class InStream {
|
|
|
26
|
|
|
27 // check() ensures there is buffer data for at least one item of size
|
|
|
28 // itemSize bytes. Returns the number of items in the buffer (up to a
|
|
|
29 // maximum of nItems).
|
|
|
30
|
|
|
31 public final int check(int itemSize, int nItems) throws Exception {
|
|
|
32 if (ptr + itemSize * nItems > end) {
|
|
|
33 if (ptr + itemSize > end)
|
|
|
34 return overrun(itemSize, nItems);
|
|
|
35
|
|
|
36 nItems = (end - ptr) / itemSize;
|
|
|
37 }
|
|
|
38 return nItems;
|
|
|
39 }
|
|
|
40
|
|
|
41 public final void check(int itemSize) throws Exception {
|
|
|
42 if (ptr + itemSize > end)
|
|
|
43 overrun(itemSize, 1);
|
|
|
44 }
|
|
|
45
|
|
|
46 // readU/SN() methods read unsigned and signed N-bit integers.
|
|
|
47
|
|
|
48 public final int readS8() throws Exception {
|
|
|
49 check(1); return b[ptr++];
|
|
|
50 }
|
|
|
51
|
|
|
52 public final int readS16() throws Exception {
|
|
|
53 check(2); int b0 = b[ptr++];
|
|
|
54 int b1 = b[ptr++] & 0xff; return b0 << 8 | b1;
|
|
|
55 }
|
|
|
56
|
|
|
57 public final int readS32() throws Exception {
|
|
|
58 check(4); int b0 = b[ptr++];
|
|
|
59 int b1 = b[ptr++] & 0xff;
|
|
|
60 int b2 = b[ptr++] & 0xff;
|
|
|
61 int b3 = b[ptr++] & 0xff;
|
|
|
62 return b0 << 24 | b1 << 16 | b2 << 8 | b3;
|
|
|
63 }
|
|
|
64
|
|
|
65 public final int readU8() throws Exception {
|
|
|
66 return readS8() & 0xff;
|
|
|
67 }
|
|
|
68
|
|
|
69 public final int readU16() throws Exception {
|
|
|
70 return readS16() & 0xffff;
|
|
|
71 }
|
|
|
72
|
|
|
73 public final int readU32() throws Exception {
|
|
|
74 return readS32() & 0xffffffff;
|
|
|
75 }
|
|
|
76
|
|
|
77 // readString() reads a string - a U32 length followed by the data.
|
|
|
78
|
|
|
79 public final String readString() throws Exception {
|
|
|
80 int len = readU32();
|
|
|
81 if (len > maxStringLength)
|
|
|
82 throw new Exception("InStream max string length exceeded");
|
|
|
83
|
|
|
84 char[] str = new char[len];
|
|
|
85 int i = 0;
|
|
|
86 while (i < len) {
|
|
|
87 int j = i + check(1, len - i);
|
|
|
88 while (i < j) {
|
|
|
89 str[i++] = (char)b[ptr++];
|
|
|
90 }
|
|
|
91 }
|
|
|
92
|
|
|
93 return new String(str);
|
|
|
94 }
|
|
|
95
|
|
|
96 // maxStringLength protects against allocating a huge buffer. Set it
|
|
|
97 // higher if you need longer strings.
|
|
|
98
|
|
|
99 public static int maxStringLength = 65535;
|
|
|
100
|
|
|
101 public final void skip(int bytes) throws Exception {
|
|
|
102 while (bytes > 0) {
|
|
|
103 int n = check(1, bytes);
|
|
|
104 ptr += n;
|
|
|
105 bytes -= n;
|
|
|
106 }
|
|
|
107 }
|
|
|
108
|
|
|
109 // readBytes() reads an exact number of bytes into an array at an offset.
|
|
|
110
|
|
|
111 public void readBytes(byte[] data, int offset, int length) throws Exception {
|
|
|
112 int offsetEnd = offset + length;
|
|
|
113 while (offset < offsetEnd) {
|
|
|
114 int n = check(1, offsetEnd - offset);
|
|
|
115 System.arraycopy(b, ptr, data, offset, n);
|
|
|
116 ptr += n;
|
|
|
117 offset += n;
|
|
|
118 }
|
|
|
119 }
|
|
|
120
|
|
|
121 // readOpaqueN() reads a quantity "without byte-swapping". Because java has
|
|
|
122 // no byte-ordering, we just use big-endian.
|
|
|
123
|
|
|
124 public final int readOpaque8() throws Exception {
|
|
|
125 return readU8();
|
|
|
126 }
|
|
|
127
|
|
|
128 public final int readOpaque16() throws Exception {
|
|
|
129 return readU16();
|
|
|
130 }
|
|
|
131
|
|
|
132 public final int readOpaque32() throws Exception {
|
|
|
133 return readU32();
|
|
|
134 }
|
|
|
135
|
|
|
136 public final int readOpaque24A() throws Exception {
|
|
|
137 check(3); int b0 = b[ptr++];
|
|
|
138 int b1 = b[ptr++]; int b2 = b[ptr++];
|
|
|
139 return b0 << 24 | b1 << 16 | b2 << 8;
|
|
|
140 }
|
|
|
141
|
|
|
142 public final int readOpaque24B() throws Exception {
|
|
|
143 check(3); int b0 = b[ptr++];
|
|
|
144 int b1 = b[ptr++]; int b2 = b[ptr++];
|
|
|
145 return b0 << 16 | b1 << 8 | b2;
|
|
|
146 }
|
|
|
147
|
|
|
148 // pos() returns the position in the stream.
|
|
|
149
|
|
|
150 abstract public int pos();
|
|
|
151
|
|
|
152 // bytesAvailable() returns true if at least one byte can be read from the
|
|
|
153 // stream without blocking. i.e. if false is returned then readU8() would
|
|
|
154 // block.
|
|
|
155
|
|
|
156 public boolean bytesAvailable() { return end != ptr; }
|
|
|
157
|
|
|
158 // getbuf(), getptr(), getend() and setptr() are "dirty" methods which allow
|
|
|
159 // you to manipulate the buffer directly. This is useful for a stream which
|
|
|
160 // is a wrapper around an underlying stream.
|
|
|
161
|
|
|
162 public final byte[] getbuf() { return b; }
|
|
|
163 public final int getptr() { return ptr; }
|
|
|
164 public final int getend() { return end; }
|
|
|
165 public final void setptr(int p) { ptr = p; }
|
|
|
166
|
|
|
167 // overrun() is implemented by a derived class to cope with buffer overrun.
|
|
|
168 // It ensures there are at least itemSize bytes of buffer data. Returns
|
|
|
169 // the number of items in the buffer (up to a maximum of nItems). itemSize
|
|
|
170 // is supposed to be "small" (a few bytes).
|
|
|
171
|
|
|
172 abstract protected int overrun(int itemSize, int nItems) throws Exception;
|
|
|
173
|
|
|
174 protected InStream() {}
|
|
|
175 protected byte[] b;
|
|
|
176 protected int ptr;
|
|
|
177 protected int end;
|
|
|
178 }
|
