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
|
/**
* @file llpredicate.h
* @brief abstraction for filtering objects by predicates, with arbitrary boolean expressions
*
* $LicenseInfo:firstyear=2008&license=viewerlgpl$
* Second Life Viewer Source Code
* Copyright (C) 2010, Linden Research, Inc.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation;
* version 2.1 of the License only.
*
* This library 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
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
* $/LicenseInfo$
*/
#ifndef LL_LLPREDICATE_H
#define LL_LLPREDICATE_H
#include "llerror.h"
namespace LLPredicate
{
template<typename ENUM> class Rule;
template<typename ENUM>
struct Value
{
friend Rule<ENUM>;
public:
Value(ENUM e)
: mPredicateFlags(0x1),
mPredicateCombinationFlags(0x1)
{
add(e);
}
Value()
: mPredicateFlags(0x1),
mPredicateCombinationFlags(0x1)
{}
void add(ENUM predicate)
{
llassert(predicate < 5);
if (!has(predicate))
{
int predicate_flag = 0x1 << (0x1 << (int)predicate);
mPredicateCombinationFlags *= predicate_flag;
mPredicateFlags |= predicate_flag;
}
}
void remove(ENUM predicate)
{
llassert(predicate < 5);
int predicate_flag = 0x1 << (0x1 << (int)predicate);
if (mPredicateFlags & predicate_flag)
{
mPredicateCombinationFlags /= predicate_flag;
mPredicateFlags &= ~predicate_flag;
}
}
void unknown(ENUM predicate)
{
add(predicate);
int predicate_shift = 0x1 << (int)predicate;
mPredicateCombinationFlags |= mPredicateCombinationFlags << predicate_shift;
}
bool has(ENUM predicate)
{
int predicate_flag = 0x1 << (0x1 << (int)predicate);
return (mPredicateFlags & predicate_flag) != 0;
}
private:
int mPredicateCombinationFlags;
int mPredicateFlags;
};
struct EmptyRule {};
template<typename ENUM>
class Rule
{
public:
Rule(ENUM value)
: mPredicateRequirements(predicateFromValue(value))
{}
Rule()
: mPredicateRequirements(0x1)
{}
Rule operator~()
{
Rule new_rule;
new_rule.mPredicateRequirements = ~mPredicateRequirements;
return new_rule;
}
Rule operator &&(const Rule& other)
{
Rule new_rule;
new_rule.mPredicateRequirements = mPredicateRequirements & other.mPredicateRequirements;
return new_rule;
}
Rule operator ||(const Rule& other)
{
Rule new_rule;
new_rule.mPredicateRequirements = mPredicateRequirements | other.mPredicateRequirements;
return new_rule;
}
bool check(const Value<ENUM>& value) const
{
return ((value.mPredicateCombinationFlags | 0x1) & mPredicateRequirements) != 0;
}
static int predicateFromValue(ENUM value)
{
llassert(value < 5);
static const int predicates[5] =
{
0xAAAAaaaa, // 10101010101010101010101010101010
0xCCCCcccc, // 11001100110011001100110011001100
0xF0F0F0F0, // 11110000111100001111000011110000
0xFF00FF00, // 11111111000000001111111100000000
0xFFFF0000 // 11111111111111110000000000000000
};
return predicates[value];
}
bool isTriviallyTrue() const
{
return mPredicateRequirements & 0x1;
}
bool isTriviallyFalse() const
{
return mPredicateRequirements == 0;
}
private:
int mPredicateRequirements;
};
template<typename ENUM>
Rule<ENUM> make_rule(ENUM e) { return Rule<ENUM>(e);}
// return generic empty rule class to avoid requiring template argument to create an empty rule
EmptyRule make_rule();
}
#endif // LL_LLPREDICATE_H
|
