1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
|
/* Copyright (C) 2002-2003 RealVNC Ltd. All Rights Reserved.
*
* This is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This software is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this software; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307,
* USA.
*/
//
// rdr::InStream marshalls data from a buffer stored in RDR (RFB Data
// Representation).
//
#ifndef __RDR_INSTREAM_H__
#define __RDR_INSTREAM_H__
#include <rdr/types.h>
#include <string.h> // for memcpy
namespace rdr {
class InStream {
public:
virtual ~InStream() {}
// check() ensures there is buffer data for at least one item of size
// itemSize bytes. Returns the number of items in the buffer (up to a
// maximum of nItems). If wait is false, then instead of blocking to wait
// for the bytes, zero is returned if the bytes are not immediately
// available.
inline int check(int itemSize, int nItems=1, bool wait=true)
{
if (ptr + itemSize * nItems > end) {
if (ptr + itemSize > end)
return overrun(itemSize, nItems, wait);
nItems = (end - ptr) / itemSize;
}
return nItems;
}
// checkNoWait() tries to make sure that the given number of bytes can
// be read without blocking. It returns true if this is the case, false
// otherwise. The length must be "small" (less than the buffer size).
inline bool checkNoWait(int length) { return check(length, 1, false)!=0; }
// readU/SN() methods read unsigned and signed N-bit integers.
inline U8 readU8() { check(1); return *ptr++; }
inline U16 readU16() { check(2); int b0 = *ptr++; int b1 = *ptr++;
return b0 << 8 | b1; }
inline U32 readU32() { check(4); int b0 = *ptr++; int b1 = *ptr++;
int b2 = *ptr++; int b3 = *ptr++;
return b0 << 24 | b1 << 16 | b2 << 8 | b3; }
inline S8 readS8() { return (S8) readU8(); }
inline S16 readS16() { return (S16)readU16(); }
inline S32 readS32() { return (S32)readU32(); }
// readCompactLength() reads 1..3 bytes representing length of the data
// following. This method is used by the Tight decoder.
inline unsigned int readCompactLength() {
U8 b = readU8();
int result = (int)b & 0x7F;
if (b & 0x80) {
b = readU8();
result |= ((int)b & 0x7F) << 7;
if (b & 0x80) {
b = readU8();
result |= ((int)b & 0xFF) << 14;
}
}
return result;
}
// readString() reads a string - a U32 length followed by the data.
// Returns a null-terminated string - the caller should delete[] it
// afterwards.
char* readString();
// maxStringLength protects against allocating a huge buffer. Set it
// higher if you need longer strings.
static U32 maxStringLength;
inline void skip(int bytes) {
while (bytes > 0) {
int n = check(1, bytes);
ptr += n;
bytes -= n;
}
}
// readBytes() reads an exact number of bytes.
virtual void readBytes(void* data, int length) {
U8* dataPtr = (U8*)data;
U8* dataEnd = dataPtr + length;
while (dataPtr < dataEnd) {
int n = check(1, dataEnd - dataPtr);
memcpy(dataPtr, ptr, n);
ptr += n;
dataPtr += n;
}
}
// readOpaqueN() reads a quantity without byte-swapping.
inline U8 readOpaque8() { return readU8(); }
inline U16 readOpaque16() { check(2); U16 r; ((U8*)&r)[0] = *ptr++;
((U8*)&r)[1] = *ptr++; return r; }
inline U32 readOpaque32() { check(4); U32 r; ((U8*)&r)[0] = *ptr++;
((U8*)&r)[1] = *ptr++; ((U8*)&r)[2] = *ptr++;
((U8*)&r)[3] = *ptr++; return r; }
inline U32 readOpaque24A() { check(3); U32 r=0; ((U8*)&r)[0] = *ptr++;
((U8*)&r)[1] = *ptr++; ((U8*)&r)[2] = *ptr++;
return r; }
inline U32 readOpaque24B() { check(3); U32 r=0; ((U8*)&r)[1] = *ptr++;
((U8*)&r)[2] = *ptr++; ((U8*)&r)[3] = *ptr++;
return r; }
// pos() returns the position in the stream.
virtual int pos() = 0;
// getptr(), getend() and setptr() are "dirty" methods which allow you to
// manipulate the buffer directly. This is useful for a stream which is a
// wrapper around an underlying stream.
inline const U8* getptr() const { return ptr; }
inline const U8* getend() const { return end; }
inline void setptr(const U8* p) { ptr = p; }
private:
// overrun() is implemented by a derived class to cope with buffer overrun.
// It ensures there are at least itemSize bytes of buffer data. Returns
// the number of items in the buffer (up to a maximum of nItems). itemSize
// is supposed to be "small" (a few bytes). If wait is false, then
// instead of blocking to wait for the bytes, zero is returned if the bytes
// are not immediately available.
virtual int overrun(int itemSize, int nItems, bool wait=true) = 0;
protected:
InStream() {}
const U8* ptr;
const U8* end;
};
}
#endif
|
