sat_counter.test.cc revision 14210 
1/*
2 * Copyright (c) 2019 Inria
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: Daniel Carvalho
29 */
30
31#include <gtest/gtest.h>
32
33#include <utility>
34
35#include "base/sat_counter.hh"
36
37/**
38 * Test if the maximum value is indeed the maximum value reachable.
39 */
40TEST(SatCounterTest, MaximumValue)
41{
42    const unsigned bits = 3;
43    const unsigned max_value = (1 << bits) - 1;
44    SatCounter counter(bits);
45
46    for (int i = 0; i < 2*max_value; i++) {
47        counter++;
48    }
49
50    ASSERT_EQ(counter, max_value);
51}
52
53/**
54 * Test if the minimum value is indeed the mimimum value reachable.
55 */
56TEST(SatCounterTest, MinimumValue)
57{
58    const unsigned bits = 3;
59    SatCounter counter(bits);
60
61    for (int i = 0; i < 2; i++) {
62        counter--;
63    }
64
65    ASSERT_EQ(counter, 0);
66}
67
68/**
69 * Test initializing the counter with a value, updating it and then resetting.
70 */
71TEST(SatCounterTest, InitialValue)
72{
73    const unsigned bits = 3;
74    const unsigned initial_value = 4;
75    SatCounter counter(bits, initial_value);
76    ASSERT_EQ(counter, initial_value);
77    counter++;
78    counter.reset();
79    ASSERT_EQ(counter, initial_value);
80}
81
82/**
83 * Test calculating saturation percentile.
84 */
85TEST(SatCounterTest, SaturationPercentile)
86{
87    const unsigned bits = 3;
88    const unsigned max_value = (1 << bits) - 1;
89    SatCounter counter(bits);
90
91    ASSERT_FALSE(counter.isSaturated());
92    for (double value = 0.0; value <= max_value; value++, counter++) {
93        const double saturation = value / max_value;
94        ASSERT_DOUBLE_EQ(counter.calcSaturation(), saturation);
95    }
96    ASSERT_TRUE(counter.isSaturated());
97}
98
99/**
100 * Test abrupt saturation.
101 */
102TEST(SatCounterTest, Saturate)
103{
104    const unsigned bits = 3;
105    const unsigned max_value = (1 << bits) - 1;
106    SatCounter counter(bits);
107    counter++;
108    ASSERT_FALSE(counter.isSaturated());
109
110    // Make sure the value added is what was missing to saturate
111    const unsigned diff = counter.saturate();
112    ASSERT_EQ(diff, max_value - 1);
113    ASSERT_TRUE(counter.isSaturated());
114}
115
116/**
117 * Test back and forth against an int.
118 */
119TEST(SatCounterTest, IntComparison)
120{
121    const unsigned bits = 3;
122    SatCounter counter(bits);
123    int value = 0;
124
125    ASSERT_EQ(counter++, value++);
126    ASSERT_EQ(counter++, value++);
127    ASSERT_EQ(counter--, value--);
128    ASSERT_EQ(counter++, value++);
129    ASSERT_EQ(counter++, value++);
130    ASSERT_EQ(counter--, value--);
131    ASSERT_EQ(counter++, value++);
132    ASSERT_EQ(counter--, value--);
133    ASSERT_EQ(counter--, value--);
134    ASSERT_EQ(counter++, value++);
135    ASSERT_EQ(counter--, value--);
136    ASSERT_EQ(counter--, value--);
137    ASSERT_EQ(counter, 0);
138}
139
140/**
141 * Test shift operators.
142 */
143TEST(SatCounterTest, Shift)
144{
145    const unsigned bits = 3;
146    const unsigned max_value = (1 << bits) - 1;
147    const unsigned initial_value = 1;
148    SatCounter counter(bits, initial_value);
149    SatCounter other(bits, initial_value);
150    // The saturated shift value is just enough to saturate, since greater
151    // values could generate undefined behavior
152    SatCounter saturated_counter(bits, bits);
153    int value = initial_value;
154
155    // Test random shifts
156    counter <<= 2;
157    value <<= 2;
158    ASSERT_EQ(counter, value);
159    counter >>= 1;
160    value >>= 1;
161    ASSERT_EQ(counter, value);
162
163    // Test saturation
164    counter <<= bits;
165    ASSERT_EQ(counter, max_value);
166
167    // Test zeroing
168    counter >>= bits;
169    ASSERT_EQ(counter, 0);
170
171    // Test saturation against other saturating counter
172    counter.reset();
173    value = initial_value;
174    counter <<= other;
175    value <<= other;
176    ASSERT_EQ(counter, value);
177    counter <<= saturated_counter;
178    value = max_value;
179    ASSERT_EQ(counter, max_value);
180
181    // Test zeroing against other saturating counter
182    counter >>= other;
183    value >>= other;
184    ASSERT_EQ(counter, value);
185    counter >>= saturated_counter;
186    ASSERT_EQ(counter, 0);
187}
188
189/**
190 * Test both pre and post operators.
191 */
192TEST(SatCounterTest, PrePostOperators)
193{
194    const unsigned bits = 3;
195    const unsigned max_value = (1 << bits) - 1;
196    SatCounter counter_pre(bits);
197    SatCounter counter_post(bits);
198
199    for (int i = 0; i < 2*max_value; i++) {
200        counter_post++;
201        SatCounter value_pre = ++counter_pre;
202        ASSERT_EQ(counter_post, value_pre);
203    }
204
205    ASSERT_EQ(counter_pre, max_value);
206    ASSERT_EQ(counter_post, max_value);
207
208    for (int i = 0; i < 2*max_value; i++) {
209        counter_post--;
210        SatCounter value_pre = --counter_pre;
211        ASSERT_EQ(counter_post, value_pre);
212    }
213
214    ASSERT_EQ(counter_pre, 0);
215    ASSERT_EQ(counter_post, 0);
216}
217
218/**
219 * Test copy and move for both constructor and assignment.
220 */
221TEST(SatCounterTest, CopyMove)
222{
223    const unsigned bits = 3;
224    const unsigned max_value = (1 << bits) - 1;
225    const unsigned initial_value = 1;
226    SatCounter counter(bits, initial_value);
227    SatCounter deep_copy(1);
228    SatCounter counter_copy(2);
229
230    // Increase counter value so that we can check if the inner counter is
231    // being copied
232    counter++;
233
234    // Copy counter using both the copy constructor and the copy assignment
235    SatCounter counter_copy_constructor(counter);
236    deep_copy = counter_copy = counter;
237    ASSERT_EQ(counter_copy_constructor, initial_value + 1);
238    ASSERT_EQ(counter_copy, initial_value + 1);
239    ASSERT_EQ(deep_copy, initial_value + 1);
240
241    // Make sure max value is the same for all of them, and that modifying
242    // the copies does not modify the original
243    for (int i = 0; i < 2*max_value; i++) {
244        counter_copy_constructor++;
245        counter_copy++;
246        deep_copy++;
247    }
248    ASSERT_EQ(counter, initial_value + 1);
249    ASSERT_EQ(counter_copy_constructor, max_value);
250    ASSERT_EQ(counter_copy, max_value);
251    ASSERT_EQ(deep_copy, max_value);
252
253    // Make sure initial value is the same for all of them
254    counter_copy_constructor.reset();
255    counter_copy.reset();
256    deep_copy.reset();
257    ASSERT_EQ(counter_copy_constructor, initial_value);
258    ASSERT_EQ(counter_copy, initial_value);
259    ASSERT_EQ(deep_copy, initial_value);
260
261    // Now check move
262    SatCounter counter_move_constructor(std::move(counter));
263    ASSERT_EQ(counter, 0);
264    ASSERT_EQ(counter_move_constructor, initial_value + 1);
265
266    SatCounter counter_move(bits);
267    counter_move = std::move(counter_move_constructor);
268    ASSERT_EQ(counter_move_constructor, 0);
269    ASSERT_EQ(counter_move, initial_value + 1);
270}
271
272/**
273 * Test add-assignment and subtract assignment.
274 */
275TEST(SatCounterTest, AddSubAssignment)
276{
277    const unsigned bits = 3;
278    const unsigned max_value = (1 << bits) - 1;
279    SatCounter counter(bits);
280    SatCounter other(bits, 2);
281    SatCounter saturated_counter(bits, max_value);
282    int value = 0;
283
284    // Test add-assignment for a few random values and then saturate
285    counter += 2;
286    value += 2;
287    ASSERT_EQ(counter, value);
288    counter += 3;
289    value += 3;
290    ASSERT_EQ(counter, value);
291    counter += max_value;
292    value = max_value;
293    ASSERT_EQ(counter, value);
294
295    // Test subtract-assignment for a few random values until back to zero
296    counter -= 2;
297    value -= 2;
298    ASSERT_EQ(counter, value);
299    counter -= 3;
300    value -= 3;
301    ASSERT_EQ(counter, value);
302    counter -= max_value;
303    value = 0;
304    ASSERT_EQ(counter, value);
305
306    // Test add-assignment of other saturating counter
307    counter += other;
308    value += other;
309    ASSERT_EQ(counter, value);
310    counter += saturated_counter;
311    value = max_value;
312    ASSERT_EQ(counter, saturated_counter);
313
314    // Test subtract-assignment of other saturating counter
315    counter -= other;
316    value -= other;
317    ASSERT_EQ(counter, value);
318    counter -= saturated_counter;
319    ASSERT_EQ(counter, 0);
320}
321
322