1 /*
2 * Copyright © 2018 Intel Corporation
3 * Copyright © 2019 Valve Corporation
4 *
5 * Permission is hereby granted, free of charge, to any person obtaining a
6 * copy of this software and associated documentation files (the "Software"),
7 * to deal in the Software without restriction, including without limitation
8 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
9 * and/or sell copies of the Software, and to permit persons to whom the
10 * Software is furnished to do so, subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice (including the next
13 * paragraph) shall be included in all copies or substantial portions of the
14 * Software.
15 *
16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
21 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
22 * IN THE SOFTWARE.
23 */
24
25 #undef NDEBUG
26
27 #include <gtest/gtest.h>
28 #include "util/fast_urem_by_const.h"
29
30 #define RAND_TEST_ITERATIONS 100000
31
32 static uint32_t
rand_uint(unsigned min)33 rand_uint(unsigned min)
34 {
35 /* Make sure we get some small and large numbers and powers of two every
36 * once in a while
37 */
38 int k = rand() % 64;
39 if (k == 17) {
40 return min + (rand() % 16);
41 } else if (k == 42) {
42 return UINT32_MAX - (rand() % 16);
43 } else if (k == 9) {
44 uint32_t r;
45 do {
46 r = 1ull << (rand() % 32);
47 } while (r < min);
48 return r;
49 }
50
51 if (min == 0) {
52 uint32_t r = 0;
53 for (unsigned i = 0; i < 4; i++)
54 r |= ((uint32_t)rand() & 0xf) << i * 8;
55 return r >> (31 - (rand() % 32));
56 } else {
57 uint64_t r;
58 do {
59 r = rand_uint(0);
60 } while (r < min);
61 return r;
62 }
63 }
64
65 static void
test_case(uint32_t n,uint32_t d)66 test_case(uint32_t n, uint32_t d)
67 {
68 assert(d >= 1);
69 uint64_t magic = REMAINDER_MAGIC(d);
70 /* Note: there's already an assert inside util_fast_urem32(), so the
71 * EXPECT_EQ is only here to make sure the test fails with a wrong result
72 * even if asserts are disabled. Ideally we could disable the assert just
73 * for the test to get a better error message, but that doesn't seem too
74 * easy.
75 */
76 EXPECT_EQ(util_fast_urem32(n, d, magic), n % d);
77 }
78
TEST(fast_urem_by_const,random)79 TEST(fast_urem_by_const, random)
80 {
81 for (unsigned i = 0; i < RAND_TEST_ITERATIONS; i++) {
82 uint64_t n = rand_uint(0);
83 uint64_t d = rand_uint(1);
84 test_case(n, d);
85 }
86 }
87
TEST(fast_urem_by_const,special_cases)88 TEST(fast_urem_by_const, special_cases)
89 {
90 test_case(0, 1);
91 test_case(0, UINT32_MAX);
92 test_case(UINT32_MAX, 1);
93 test_case(1, UINT32_MAX);
94 test_case(UINT32_MAX, UINT32_MAX);
95 test_case(UINT32_MAX, UINT32_MAX - 1);
96 test_case(UINT32_MAX - 1, UINT32_MAX - 1);
97 test_case(UINT32_MAX - 2, UINT32_MAX - 1);
98 }
99
100