timebuf.hh revision 7813:7338bc628489 
1/*
2 * Copyright (c) 2004-2005 The Regents of The University of Michigan
3 * All rights reserved.
4 *
5 * Redistribution and use in source and binary forms, with or without
6 * modification, are permitted provided that the following conditions are
7 * met: redistributions of source code must retain the above copyright
8 * notice, this list of conditions and the following disclaimer;
9 * redistributions in binary form must reproduce the above copyright
10 * notice, this list of conditions and the following disclaimer in the
11 * documentation and/or other materials provided with the distribution;
12 * neither the name of the copyright holders nor the names of its
13 * contributors may be used to endorse or promote products derived from
14 * this software without specific prior written permission.
15 *
16 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
17 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
18 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
19 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
20 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
21 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
22 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
26 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27 *
28 * Authors: Nathan Binkert
29 *          Kevin Lim
30 */
31
32#ifndef __BASE_TIMEBUF_HH__
33#define __BASE_TIMEBUF_HH__
34
35#include <cassert>
36#include <cstring>
37#include <vector>
38
39template <class T>
40class TimeBuffer
41{
42  protected:
43    int past;
44    int future;
45    unsigned size;
46    int _id;
47
48    char *data;
49    std::vector<char *> index;
50    unsigned base;
51
52    void valid(int idx)
53    {
54        assert (idx >= -past && idx <= future);
55    }
56
57  public:
58    friend class wire;
59    class wire
60    {
61        friend class TimeBuffer;
62      protected:
63        TimeBuffer<T> *buffer;
64        int index;
65
66        void set(int idx)
67        {
68            buffer->valid(idx);
69            index = idx;
70        }
71
72        wire(TimeBuffer<T> *buf, int i)
73            : buffer(buf), index(i)
74        { }
75
76      public:
77        wire()
78        { }
79
80        wire(const wire &i)
81            : buffer(i.buffer), index(i.index)
82        { }
83
84        const wire &operator=(const wire &i)
85        {
86            buffer = i.buffer;
87            set(i.index);
88            return *this;
89        }
90
91        const wire &operator=(int idx)
92        {
93            set(idx);
94            return *this;
95        }
96
97        const wire &operator+=(int offset)
98        {
99            set(index + offset);
100            return *this;
101        }
102
103        const wire &operator-=(int offset)
104        {
105            set(index - offset);
106            return *this;
107        }
108
109        wire &operator++()
110        {
111            set(index + 1);
112            return *this;
113        }
114
115        wire &operator++(int)
116        {
117            int i = index;
118            set(index + 1);
119            return wire(this, i);
120        }
121
122        wire &operator--()
123        {
124            set(index - 1);
125            return *this;
126        }
127
128        wire &operator--(int)
129        {
130            int i = index;
131            set(index - 1);
132            return wire(this, i);
133        }
134        T &operator*() const { return *buffer->access(index); }
135        T *operator->() const { return buffer->access(index); }
136    };
137
138
139  public:
140    TimeBuffer(int p, int f)
141        : past(p), future(f), size(past + future + 1),
142          data(new char[size * sizeof(T)]), index(size), base(0)
143    {
144        assert(past >= 0 && future >= 0);
145        char *ptr = data;
146        for (unsigned i = 0; i < size; i++) {
147            index[i] = ptr;
148            std::memset(ptr, 0, sizeof(T));
149            new (ptr) T;
150            ptr += sizeof(T);
151        }
152
153        _id = -1;
154    }
155
156    TimeBuffer()
157        : data(NULL)
158    {
159    }
160
161    ~TimeBuffer()
162    {
163        for (unsigned i = 0; i < size; ++i)
164            (reinterpret_cast<T *>(index[i]))->~T();
165        delete [] data;
166    }
167
168    void id(int id)
169    {
170        _id = id;
171    }
172
173    int id()
174    {
175        return _id;
176    }
177
178    void
179    advance()
180    {
181        if (++base >= size)
182            base = 0;
183
184        int ptr = base + future;
185        if (ptr >= (int)size)
186            ptr -= size;
187        (reinterpret_cast<T *>(index[ptr]))->~T();
188        std::memset(index[ptr], 0, sizeof(T));
189        new (index[ptr]) T;
190    }
191
192    T *access(int idx)
193    {
194        //Need more complex math here to calculate index.
195        valid(idx);
196
197        int vector_index = idx + base;
198        if (vector_index >= (int)size) {
199            vector_index -= size;
200        } else if (vector_index < 0) {
201            vector_index += size;
202        }
203
204        return reinterpret_cast<T *>(index[vector_index]);
205    }
206
207    T &operator[](int idx)
208    {
209        //Need more complex math here to calculate index.
210        valid(idx);
211
212        int vector_index = idx + base;
213        if (vector_index >= (int)size) {
214            vector_index -= size;
215        } else if (vector_index < 0) {
216            vector_index += size;
217        }
218
219        return reinterpret_cast<T &>(*index[vector_index]);
220    }
221
222    wire getWire(int idx)
223    {
224        valid(idx);
225
226        return wire(this, idx);
227    }
228
229    wire zero()
230    {
231        return wire(this, 0);
232    }
233
234    unsigned getSize()
235    {
236        return size;
237    }
238};
239
240#endif // __BASE_TIMEBUF_HH__
241
242