97 lines
2.7 KiB
C++
97 lines
2.7 KiB
C++
// Copyright 2018 The Abseil Authors.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// https://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
|
|
#include "absl/base/internal/bits.h"
|
|
|
|
#include "gtest/gtest.h"
|
|
|
|
namespace {
|
|
|
|
int CLZ64(uint64_t n) {
|
|
int fast = absl::base_internal::CountLeadingZeros64(n);
|
|
int slow = absl::base_internal::CountLeadingZeros64Slow(n);
|
|
EXPECT_EQ(fast, slow) << n;
|
|
return fast;
|
|
}
|
|
|
|
TEST(BitsTest, CountLeadingZeros64) {
|
|
EXPECT_EQ(64, CLZ64(uint64_t{}));
|
|
EXPECT_EQ(0, CLZ64(~uint64_t{}));
|
|
|
|
for (int index = 0; index < 64; index++) {
|
|
uint64_t x = static_cast<uint64_t>(1) << index;
|
|
const auto cnt = 63 - index;
|
|
ASSERT_EQ(cnt, CLZ64(x)) << index;
|
|
ASSERT_EQ(cnt, CLZ64(x + x - 1)) << index;
|
|
}
|
|
}
|
|
|
|
int CLZ32(uint32_t n) {
|
|
int fast = absl::base_internal::CountLeadingZeros32(n);
|
|
int slow = absl::base_internal::CountLeadingZeros32Slow(n);
|
|
EXPECT_EQ(fast, slow) << n;
|
|
return fast;
|
|
}
|
|
|
|
TEST(BitsTest, CountLeadingZeros32) {
|
|
EXPECT_EQ(32, CLZ32(uint32_t{}));
|
|
EXPECT_EQ(0, CLZ32(~uint32_t{}));
|
|
|
|
for (int index = 0; index < 32; index++) {
|
|
uint32_t x = static_cast<uint32_t>(1) << index;
|
|
const auto cnt = 31 - index;
|
|
ASSERT_EQ(cnt, CLZ32(x)) << index;
|
|
ASSERT_EQ(cnt, CLZ32(x + x - 1)) << index;
|
|
ASSERT_EQ(CLZ64(x), CLZ32(x) + 32);
|
|
}
|
|
}
|
|
|
|
int CTZ64(uint64_t n) {
|
|
int fast = absl::base_internal::CountTrailingZerosNonZero64(n);
|
|
int slow = absl::base_internal::CountTrailingZerosNonZero64Slow(n);
|
|
EXPECT_EQ(fast, slow) << n;
|
|
return fast;
|
|
}
|
|
|
|
TEST(BitsTest, CountTrailingZerosNonZero64) {
|
|
EXPECT_EQ(0, CTZ64(~uint64_t{}));
|
|
|
|
for (int index = 0; index < 64; index++) {
|
|
uint64_t x = static_cast<uint64_t>(1) << index;
|
|
const auto cnt = index;
|
|
ASSERT_EQ(cnt, CTZ64(x)) << index;
|
|
ASSERT_EQ(cnt, CTZ64(~(x - 1))) << index;
|
|
}
|
|
}
|
|
|
|
int CTZ32(uint32_t n) {
|
|
int fast = absl::base_internal::CountTrailingZerosNonZero32(n);
|
|
int slow = absl::base_internal::CountTrailingZerosNonZero32Slow(n);
|
|
EXPECT_EQ(fast, slow) << n;
|
|
return fast;
|
|
}
|
|
|
|
TEST(BitsTest, CountTrailingZerosNonZero32) {
|
|
EXPECT_EQ(0, CTZ32(~uint32_t{}));
|
|
|
|
for (int index = 0; index < 32; index++) {
|
|
uint32_t x = static_cast<uint32_t>(1) << index;
|
|
const auto cnt = index;
|
|
ASSERT_EQ(cnt, CTZ32(x)) << index;
|
|
ASSERT_EQ(cnt, CTZ32(~(x - 1))) << index;
|
|
}
|
|
}
|
|
|
|
|
|
} // namespace
|