1 // Copyright (c) 2012 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/metrics/bucket_ranges.h"
6
7 #include <stdint.h>
8
9 #include "testing/gtest/include/gtest/gtest.h"
10
11 namespace base {
12 namespace {
13
TEST(BucketRangesTest,NormalSetup)14 TEST(BucketRangesTest, NormalSetup) {
15 BucketRanges ranges(5);
16 ASSERT_EQ(5u, ranges.size());
17 ASSERT_EQ(4u, ranges.bucket_count());
18
19 for (int i = 0; i < 5; ++i) {
20 EXPECT_EQ(0, ranges.range(i));
21 }
22 EXPECT_EQ(0u, ranges.checksum());
23
24 ranges.set_range(3, 100);
25 EXPECT_EQ(100, ranges.range(3));
26 }
27
TEST(BucketRangesTest,Equals)28 TEST(BucketRangesTest, Equals) {
29 // Compare empty ranges.
30 BucketRanges ranges1(3);
31 BucketRanges ranges2(3);
32 BucketRanges ranges3(5);
33
34 EXPECT_TRUE(ranges1.Equals(&ranges2));
35 EXPECT_FALSE(ranges1.Equals(&ranges3));
36 EXPECT_FALSE(ranges2.Equals(&ranges3));
37
38 // Compare full filled ranges.
39 ranges1.set_range(0, 0);
40 ranges1.set_range(1, 1);
41 ranges1.set_range(2, 2);
42 ranges1.set_checksum(100);
43 ranges2.set_range(0, 0);
44 ranges2.set_range(1, 1);
45 ranges2.set_range(2, 2);
46 ranges2.set_checksum(100);
47
48 EXPECT_TRUE(ranges1.Equals(&ranges2));
49
50 // Checksum does not match.
51 ranges1.set_checksum(99);
52 EXPECT_FALSE(ranges1.Equals(&ranges2));
53 ranges1.set_checksum(100);
54
55 // Range does not match.
56 ranges1.set_range(1, 3);
57 EXPECT_FALSE(ranges1.Equals(&ranges2));
58 }
59
TEST(BucketRangesTest,Checksum)60 TEST(BucketRangesTest, Checksum) {
61 BucketRanges ranges(3);
62 ranges.set_range(0, 0);
63 ranges.set_range(1, 1);
64 ranges.set_range(2, 2);
65
66 ranges.ResetChecksum();
67 EXPECT_EQ(289217253u, ranges.checksum());
68
69 ranges.set_range(2, 3);
70 EXPECT_FALSE(ranges.HasValidChecksum());
71
72 ranges.ResetChecksum();
73 EXPECT_EQ(2843835776u, ranges.checksum());
74 EXPECT_TRUE(ranges.HasValidChecksum());
75 }
76
77 // Table was generated similarly to sample code for CRC-32 given on:
78 // http://www.w3.org/TR/PNG/#D-CRCAppendix.
TEST(BucketRangesTest,Crc32TableTest)79 TEST(BucketRangesTest, Crc32TableTest) {
80 for (int i = 0; i < 256; ++i) {
81 uint32_t checksum = i;
82 for (int j = 0; j < 8; ++j) {
83 const uint32_t kReversedPolynomial = 0xedb88320L;
84 if (checksum & 1)
85 checksum = kReversedPolynomial ^ (checksum >> 1);
86 else
87 checksum >>= 1;
88 }
89 EXPECT_EQ(kCrcTable[i], checksum);
90 }
91 }
92
93 } // namespace
94 } // namespace base
95