blob: 424ff63ea1816b0f930277c54eb2d7e7aefd4507 [file] [log] [blame]
// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/metrics/bucket_ranges.h"
#include "testing/gtest/include/gtest/gtest.h"
namespace base {
namespace {
TEST(BucketRangesTest, NormalSetup) {
BucketRanges ranges(5);
ASSERT_EQ(5u, ranges.size());
for (int i = 0; i < 5; i++) {
EXPECT_EQ(0, ranges.range(i));
}
EXPECT_EQ(0u, ranges.checksum());
ranges.set_range(3, 100);
EXPECT_EQ(100, ranges.range(3));
}
TEST(BucketRangesTest, Equals) {
// Compare empty ranges.
BucketRanges ranges1(3);
BucketRanges ranges2(3);
BucketRanges ranges3(5);
EXPECT_TRUE(ranges1.Equals(&ranges2));
EXPECT_FALSE(ranges1.Equals(&ranges3));
EXPECT_FALSE(ranges2.Equals(&ranges3));
// Compare full filled ranges.
ranges1.set_range(0, 0);
ranges1.set_range(1, 1);
ranges1.set_range(2, 2);
ranges1.set_checksum(100);
ranges2.set_range(0, 0);
ranges2.set_range(1, 1);
ranges2.set_range(2, 2);
ranges2.set_checksum(100);
EXPECT_TRUE(ranges1.Equals(&ranges2));
// Checksum does not match.
ranges1.set_checksum(99);
EXPECT_FALSE(ranges1.Equals(&ranges2));
ranges1.set_checksum(100);
// Range does not match.
ranges1.set_range(1, 3);
EXPECT_FALSE(ranges1.Equals(&ranges2));
}
TEST(BucketRangesTest, Checksum) {
BucketRanges ranges(3);
ranges.set_range(0, 0);
ranges.set_range(1, 1);
ranges.set_range(2, 2);
ranges.ResetChecksum();
EXPECT_EQ(289217253u, ranges.checksum());
ranges.set_range(2, 3);
EXPECT_FALSE(ranges.HasValidChecksum());
ranges.ResetChecksum();
EXPECT_EQ(2843835776u, ranges.checksum());
EXPECT_TRUE(ranges.HasValidChecksum());
}
// Table was generated similarly to sample code for CRC-32 given on:
// http://www.w3.org/TR/PNG/#D-CRCAppendix.
TEST(BucketRangesTest, Crc32TableTest) {
for (int i = 0; i < 256; ++i) {
uint32 checksum = i;
for (int j = 0; j < 8; ++j) {
const uint32 kReversedPolynomial = 0xedb88320L;
if (checksum & 1)
checksum = kReversedPolynomial ^ (checksum >> 1);
else
checksum >>= 1;
}
EXPECT_EQ(kCrcTable[i], checksum);
}
}
} // namespace
} // namespace base