base.hh revision 14262:991410960fdb 
1/*
2 * Copyright (c) 2019 Inria
3 * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
4 * All rights reserved.
5 *
6 * Redistribution and use in source and binary forms, with or without
7 * modification, are permitted provided that the following conditions are
8 * met: redistributions of source code must retain the above copyright
9 * notice, this list of conditions and the following disclaimer;
10 * redistributions in binary form must reproduce the above copyright
11 * notice, this list of conditions and the following disclaimer in the
12 * documentation and/or other materials provided with the distribution;
13 * neither the name of the copyright holders nor the names of its
14 * contributors may be used to endorse or promote products derived from
15 * this software without specific prior written permission.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
18 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
19 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
20 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
21 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
22 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
23 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
24 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
25 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
26 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
27 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
28 *
29 * Authors: Daniel Carvalho
30 */
31
32#ifndef __BASE_FILTERS_BASE_HH__
33#define __BASE_FILTERS_BASE_HH__
34
35#include <vector>
36
37#include "base/intmath.hh"
38#include "base/types.hh"
39#include "params/BloomFilterBase.hh"
40#include "sim/sim_object.hh"
41
42namespace BloomFilter {
43
44class Base : public SimObject
45{
46  protected:
47    /** Number of LSB bits to ignore from the the addresses. */
48    const unsigned offsetBits;
49
50    /** The filter itself. */
51    std::vector<int> filter;
52
53    /** Number of bits needed to represent the size of the filter. */
54    const int sizeBits;
55
56    /** Threshold at which a filter entry starts being considered as set. */
57    const int setThreshold;
58
59  public:
60    /**
61     * Create and clear the filter.
62     */
63    Base(const BloomFilterBaseParams* p)
64        : SimObject(p), offsetBits(p->offset_bits), filter(p->size),
65          sizeBits(floorLog2(p->size)), setThreshold(p->threshold)
66    {
67        clear();
68    }
69    virtual ~Base() {};
70
71    /**
72     * Clear the filter by resetting all values.
73     */
74    virtual void clear()
75    {
76        for (auto& entry : filter) {
77            entry = 0;
78        }
79    }
80
81    /**
82     * Merges the contents of both filters into this' (Bloom Filter union).
83     * Both must have the same number of entries.
84     *
85     * @param other The other bloom filter to merge with.
86     */
87    virtual void
88    merge(const Base* other)
89    {
90        assert(filter.size() == other->filter.size());
91        for (int i = 0; i < filter.size(); ++i){
92            filter[i] |= other->filter[i];
93        }
94    }
95
96    /**
97     * Perform the filter specific function to set the corresponding
98     * entries (can be multiple) of an address.
99     *
100     * @param addr The address being parsed.
101     */
102    virtual void set(Addr addr) = 0;
103
104    /**
105     * Perform the filter specific function to clear the corresponding
106     * entries (can be multiple) of an address. By default a bloom
107     * filter does not support element deletion.
108     *
109     * @param addr The address being parsed.
110     */
111    virtual void unset(Addr addr) {};
112
113    /**
114     * Check if the corresponding filter entries of an address should be
115     * considered as set.
116     *
117     * @param addr The address being parsed.
118     * @return Whether the respective filter entry is set.
119     */
120    virtual bool
121    isSet(Addr addr) const
122    {
123        return getCount(addr) >= setThreshold;
124    }
125
126    /**
127     * Get the value stored in the corresponding filter entry of an address.
128     *
129     * @param addr The address being parsed.
130     * @param Get the value stored in the respective filter entry.
131     */
132    virtual int getCount(Addr addr) const { return 0; }
133
134    /**
135     * Get the total value stored in the filter entries.
136     *
137     * @return The sum of all filter entries.
138     */
139    virtual int getTotalCount() const
140    {
141        int count = 0;
142        for (const auto& entry : filter) {
143            count += entry;
144        }
145        return count;
146    }
147};
148
149} // namespace BloomFilter
150
151#endif // __BASE_FILTERS_BASE_HH__
152