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 "testing/gtest/include/gtest/gtest.h"
8
9namespace base {
10namespace {
11
12TEST(BucketRangesTest, NormalSetup) {
13  BucketRanges ranges(5);
14  ASSERT_EQ(5u, ranges.size());
15  ASSERT_EQ(4u, ranges.bucket_count());
16
17  for (int i = 0; i < 5; ++i) {
18    EXPECT_EQ(0, ranges.range(i));
19  }
20  EXPECT_EQ(0u, ranges.checksum());
21
22  ranges.set_range(3, 100);
23  EXPECT_EQ(100, ranges.range(3));
24}
25
26TEST(BucketRangesTest, Equals) {
27  // Compare empty ranges.
28  BucketRanges ranges1(3);
29  BucketRanges ranges2(3);
30  BucketRanges ranges3(5);
31
32  EXPECT_TRUE(ranges1.Equals(&ranges2));
33  EXPECT_FALSE(ranges1.Equals(&ranges3));
34  EXPECT_FALSE(ranges2.Equals(&ranges3));
35
36  // Compare full filled ranges.
37  ranges1.set_range(0, 0);
38  ranges1.set_range(1, 1);
39  ranges1.set_range(2, 2);
40  ranges1.set_checksum(100);
41  ranges2.set_range(0, 0);
42  ranges2.set_range(1, 1);
43  ranges2.set_range(2, 2);
44  ranges2.set_checksum(100);
45
46  EXPECT_TRUE(ranges1.Equals(&ranges2));
47
48  // Checksum does not match.
49  ranges1.set_checksum(99);
50  EXPECT_FALSE(ranges1.Equals(&ranges2));
51  ranges1.set_checksum(100);
52
53  // Range does not match.
54  ranges1.set_range(1, 3);
55  EXPECT_FALSE(ranges1.Equals(&ranges2));
56}
57
58TEST(BucketRangesTest, Checksum) {
59  BucketRanges ranges(3);
60  ranges.set_range(0, 0);
61  ranges.set_range(1, 1);
62  ranges.set_range(2, 2);
63
64  ranges.ResetChecksum();
65  EXPECT_EQ(289217253u, ranges.checksum());
66
67  ranges.set_range(2, 3);
68  EXPECT_FALSE(ranges.HasValidChecksum());
69
70  ranges.ResetChecksum();
71  EXPECT_EQ(2843835776u, ranges.checksum());
72  EXPECT_TRUE(ranges.HasValidChecksum());
73}
74
75// Table was generated similarly to sample code for CRC-32 given on:
76// http://www.w3.org/TR/PNG/#D-CRCAppendix.
77TEST(BucketRangesTest, Crc32TableTest) {
78  for (int i = 0; i < 256; ++i) {
79    uint32 checksum = i;
80    for (int j = 0; j < 8; ++j) {
81      const uint32 kReversedPolynomial = 0xedb88320L;
82      if (checksum & 1)
83        checksum = kReversedPolynomial ^ (checksum >> 1);
84      else
85        checksum >>= 1;
86    }
87    EXPECT_EQ(kCrcTable[i], checksum);
88  }
89}
90
91}  // namespace
92}  // namespace base
93