Export of internal Abseil changes
--
0bfa836596a9c787a2f0bdc283011dd1f6810c6e by Benjamin Barenblat <bbaren@google.com>:
Ignore missing CPU frequency on more architectures
Linux on MIPS, PA-RISC, RISC-V, and SystemZ doesn’t expose the nominal
CPU frequency via /sys, so don’t worry if `NominalCPUFrequency` returns
1.0 on those platforms.
Some POWER machines expose the CPU frequency; others do not. Since we
can’t predict which type of machine the tests will run on, simply
disable testing for `NominalCPUFrequency` on POWER.
PiperOrigin-RevId: 347079873
--
492b6834ed4a07cbc3abccd846f7e37d8c556ee5 by Benjamin Barenblat <bbaren@google.com>:
Use ABSL_HAVE_THREAD_LOCAL macro instead of copying code
Reduce code duplication by checking the ABSL_HAVE_THREAD_LOCAL macro
instead of copying code from base/config.h.
PiperOrigin-RevId: 347079561
--
8d656efce4da9cb032094377e58493d98427a536 by Abseil Team <absl-team@google.com>:
Rollback
PiperOrigin-RevId: 347078779
--
221bc69ec6dd7e2777ffcff6942584f979ef6382 by Abseil Team <absl-team@google.com>:
Add flag for 'shallow subcord' feature for experimental ring buffer rollout
There is a potential trade-off of CPU cost vs over-sharing cord data for subcord of large cords. This flag allows making subcords shallow for ringbuffers (with a potential larger waste of referenced source cords), which allows us to make subcord fast for this apps that do no persist (unmodified / plain copied) sub cords.
This change also introduces constants for the default settings, intended to keep the internal cord settings concistent with external flags.
PiperOrigin-RevId: 347053271
--
00a56c24293566734009f6bf2169a83fb37a35ba by Abseil Team <absl-team@google.com>:
Revert the usage of variant<> in Cord iterator and reader.
The introduction of the variant may lead to some missed compiler optimizations.
PiperOrigin-RevId: 347053041
--
c7b7b5ed7e3ab46b1e75b80f1a7de0bda26c8f70 by Chris Kennelly <ckennelly@google.com>:
Release library for integer power-of-2 functions and bit counting.
PiperOrigin-RevId: 347035065
--
5a035c0d9840b251967f9e7039fc6a4e01dd52f3 by Abseil Team <absl-team@google.com>:
Restructure Cord::ChunkIterator for future ring buffer support.
PiperOrigin-RevId: 346890054
GitOrigin-RevId: 0bfa836596a9c787a2f0bdc283011dd1f6810c6e
Change-Id: I3a58e2a44cb4c6f2116c43e2a4ccbc319d3ccecf
diff --git a/absl/numeric/bits_test.cc b/absl/numeric/bits_test.cc
new file mode 100644
index 0000000..8bf7bc9
--- /dev/null
+++ b/absl/numeric/bits_test.cc
@@ -0,0 +1,565 @@
+// Copyright 2020 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/numeric/bits.h"
+
+#include <limits>
+
+#include "gmock/gmock.h"
+#include "gtest/gtest.h"
+#include "absl/random/random.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace {
+
+TEST(Rotate, Left) {
+ static_assert(rotl(uint8_t{0x12}, 0) == uint8_t{0x12}, "");
+ static_assert(rotl(uint16_t{0x1234}, 0) == uint16_t{0x1234}, "");
+ static_assert(rotl(uint32_t{0x12345678UL}, 0) == uint32_t{0x12345678UL}, "");
+ static_assert(rotl(uint64_t{0x12345678ABCDEF01ULL}, 0) ==
+ uint64_t{0x12345678ABCDEF01ULL},
+ "");
+
+ EXPECT_EQ(rotl(uint8_t{0x12}, 0), uint8_t{0x12});
+ EXPECT_EQ(rotl(uint16_t{0x1234}, 0), uint16_t{0x1234});
+ EXPECT_EQ(rotl(uint32_t{0x12345678UL}, 0), uint32_t{0x12345678UL});
+ EXPECT_EQ(rotl(uint64_t{0x12345678ABCDEF01ULL}, 0),
+ uint64_t{0x12345678ABCDEF01ULL});
+
+ EXPECT_EQ(rotl(uint8_t{0x12}, 8), uint8_t{0x12});
+ EXPECT_EQ(rotl(uint16_t{0x1234}, 16), uint16_t{0x1234});
+ EXPECT_EQ(rotl(uint32_t{0x12345678UL}, 32), uint32_t{0x12345678UL});
+ EXPECT_EQ(rotl(uint64_t{0x12345678ABCDEF01ULL}, 64),
+ uint64_t{0x12345678ABCDEF01ULL});
+
+ EXPECT_EQ(rotl(uint8_t{0x12}, -8), uint8_t{0x12});
+ EXPECT_EQ(rotl(uint16_t{0x1234}, -16), uint16_t{0x1234});
+ EXPECT_EQ(rotl(uint32_t{0x12345678UL}, -32), uint32_t{0x12345678UL});
+ EXPECT_EQ(rotl(uint64_t{0x12345678ABCDEF01ULL}, -64),
+ uint64_t{0x12345678ABCDEF01ULL});
+
+ EXPECT_EQ(rotl(uint8_t{0x12}, 4), uint8_t{0x21});
+ EXPECT_EQ(rotl(uint16_t{0x1234}, 4), uint16_t{0x2341});
+ EXPECT_EQ(rotl(uint32_t{0x12345678UL}, 4), uint32_t{0x23456781UL});
+ EXPECT_EQ(rotl(uint64_t{0x12345678ABCDEF01ULL}, 4),
+ uint64_t{0x2345678ABCDEF011ULL});
+
+ EXPECT_EQ(rotl(uint8_t{0x12}, -4), uint8_t{0x21});
+ EXPECT_EQ(rotl(uint16_t{0x1234}, -4), uint16_t{0x4123});
+ EXPECT_EQ(rotl(uint32_t{0x12345678UL}, -4), uint32_t{0x81234567UL});
+ EXPECT_EQ(rotl(uint64_t{0x12345678ABCDEF01ULL}, -4),
+ uint64_t{0x112345678ABCDEF0ULL});
+}
+
+TEST(Rotate, Right) {
+ static_assert(rotr(uint8_t{0x12}, 0) == uint8_t{0x12}, "");
+ static_assert(rotr(uint16_t{0x1234}, 0) == uint16_t{0x1234}, "");
+ static_assert(rotr(uint32_t{0x12345678UL}, 0) == uint32_t{0x12345678UL}, "");
+ static_assert(rotr(uint64_t{0x12345678ABCDEF01ULL}, 0) ==
+ uint64_t{0x12345678ABCDEF01ULL},
+ "");
+
+ EXPECT_EQ(rotr(uint8_t{0x12}, 0), uint8_t{0x12});
+ EXPECT_EQ(rotr(uint16_t{0x1234}, 0), uint16_t{0x1234});
+ EXPECT_EQ(rotr(uint32_t{0x12345678UL}, 0), uint32_t{0x12345678UL});
+ EXPECT_EQ(rotr(uint64_t{0x12345678ABCDEF01ULL}, 0),
+ uint64_t{0x12345678ABCDEF01ULL});
+
+ EXPECT_EQ(rotr(uint8_t{0x12}, 8), uint8_t{0x12});
+ EXPECT_EQ(rotr(uint16_t{0x1234}, 16), uint16_t{0x1234});
+ EXPECT_EQ(rotr(uint32_t{0x12345678UL}, 32), uint32_t{0x12345678UL});
+ EXPECT_EQ(rotr(uint64_t{0x12345678ABCDEF01ULL}, 64),
+ uint64_t{0x12345678ABCDEF01ULL});
+
+ EXPECT_EQ(rotr(uint8_t{0x12}, -8), uint8_t{0x12});
+ EXPECT_EQ(rotr(uint16_t{0x1234}, -16), uint16_t{0x1234});
+ EXPECT_EQ(rotr(uint32_t{0x12345678UL}, -32), uint32_t{0x12345678UL});
+ EXPECT_EQ(rotr(uint64_t{0x12345678ABCDEF01ULL}, -64),
+ uint64_t{0x12345678ABCDEF01ULL});
+
+ EXPECT_EQ(rotr(uint8_t{0x12}, 4), uint8_t{0x21});
+ EXPECT_EQ(rotr(uint16_t{0x1234}, 4), uint16_t{0x4123});
+ EXPECT_EQ(rotr(uint32_t{0x12345678UL}, 4), uint32_t{0x81234567UL});
+ EXPECT_EQ(rotr(uint64_t{0x12345678ABCDEF01ULL}, 4),
+ uint64_t{0x112345678ABCDEF0ULL});
+
+ EXPECT_EQ(rotr(uint8_t{0x12}, -4), uint8_t{0x21});
+ EXPECT_EQ(rotr(uint16_t{0x1234}, -4), uint16_t{0x2341});
+ EXPECT_EQ(rotr(uint32_t{0x12345678UL}, -4), uint32_t{0x23456781UL});
+ EXPECT_EQ(rotr(uint64_t{0x12345678ABCDEF01ULL}, -4),
+ uint64_t{0x2345678ABCDEF011ULL});
+}
+
+TEST(Rotate, Symmetry) {
+ // rotr(x, s) is equivalent to rotl(x, -s)
+ absl::BitGen rng;
+ constexpr int kTrials = 100;
+
+ for (int i = 0; i < kTrials; ++i) {
+ uint8_t value = absl::Uniform(rng, std::numeric_limits<uint8_t>::min(),
+ std::numeric_limits<uint8_t>::max());
+ int shift = absl::Uniform(rng, -2 * std::numeric_limits<uint8_t>::digits,
+ 2 * std::numeric_limits<uint8_t>::digits);
+
+ EXPECT_EQ(rotl(value, shift), rotr(value, -shift));
+ }
+
+ for (int i = 0; i < kTrials; ++i) {
+ uint16_t value = absl::Uniform(rng, std::numeric_limits<uint16_t>::min(),
+ std::numeric_limits<uint16_t>::max());
+ int shift = absl::Uniform(rng, -2 * std::numeric_limits<uint16_t>::digits,
+ 2 * std::numeric_limits<uint16_t>::digits);
+
+ EXPECT_EQ(rotl(value, shift), rotr(value, -shift));
+ }
+
+ for (int i = 0; i < kTrials; ++i) {
+ uint32_t value = absl::Uniform(rng, std::numeric_limits<uint32_t>::min(),
+ std::numeric_limits<uint32_t>::max());
+ int shift = absl::Uniform(rng, -2 * std::numeric_limits<uint32_t>::digits,
+ 2 * std::numeric_limits<uint32_t>::digits);
+
+ EXPECT_EQ(rotl(value, shift), rotr(value, -shift));
+ }
+
+ for (int i = 0; i < kTrials; ++i) {
+ uint64_t value = absl::Uniform(rng, std::numeric_limits<uint64_t>::min(),
+ std::numeric_limits<uint64_t>::max());
+ int shift = absl::Uniform(rng, -2 * std::numeric_limits<uint64_t>::digits,
+ 2 * std::numeric_limits<uint64_t>::digits);
+
+ EXPECT_EQ(rotl(value, shift), rotr(value, -shift));
+ }
+}
+
+TEST(Counting, LeadingZeroes) {
+#if ABSL_INTERNAL_HAS_CONSTEXPR_CLZ
+ static_assert(countl_zero(uint8_t{}) == 8, "");
+ static_assert(countl_zero(static_cast<uint8_t>(-1)) == 0, "");
+ static_assert(countl_zero(uint16_t{}) == 16, "");
+ static_assert(countl_zero(static_cast<uint16_t>(-1)) == 0, "");
+ static_assert(countl_zero(uint32_t{}) == 32, "");
+ static_assert(countl_zero(~uint32_t{}) == 0, "");
+ static_assert(countl_zero(uint64_t{}) == 64, "");
+ static_assert(countl_zero(~uint64_t{}) == 0, "");
+#endif
+
+ EXPECT_EQ(countl_zero(uint8_t{}), 8);
+ EXPECT_EQ(countl_zero(static_cast<uint8_t>(-1)), 0);
+ EXPECT_EQ(countl_zero(uint16_t{}), 16);
+ EXPECT_EQ(countl_zero(static_cast<uint16_t>(-1)), 0);
+ EXPECT_EQ(countl_zero(uint32_t{}), 32);
+ EXPECT_EQ(countl_zero(~uint32_t{}), 0);
+ EXPECT_EQ(countl_zero(uint64_t{}), 64);
+ EXPECT_EQ(countl_zero(~uint64_t{}), 0);
+
+ for (int i = 0; i < 8; i++) {
+ EXPECT_EQ(countl_zero(static_cast<uint8_t>(1u << i)), 7 - i);
+ }
+
+ for (int i = 0; i < 16; i++) {
+ EXPECT_EQ(countl_zero(static_cast<uint16_t>(1u << i)), 15 - i);
+ }
+
+ for (int i = 0; i < 32; i++) {
+ EXPECT_EQ(countl_zero(uint32_t{1} << i), 31 - i);
+ }
+
+ for (int i = 0; i < 64; i++) {
+ EXPECT_EQ(countl_zero(uint64_t{1} << i), 63 - i);
+ }
+}
+
+TEST(Counting, LeadingOnes) {
+#if ABSL_INTERNAL_HAS_CONSTEXPR_CLZ
+ static_assert(countl_one(uint8_t{}) == 0, "");
+ static_assert(countl_one(static_cast<uint8_t>(-1)) == 8, "");
+ static_assert(countl_one(uint16_t{}) == 0, "");
+ static_assert(countl_one(static_cast<uint16_t>(-1)) == 16, "");
+ static_assert(countl_one(uint32_t{}) == 0, "");
+ static_assert(countl_one(~uint32_t{}) == 32, "");
+ static_assert(countl_one(uint64_t{}) == 0, "");
+ static_assert(countl_one(~uint64_t{}) == 64, "");
+#endif
+
+ EXPECT_EQ(countl_one(uint8_t{}), 0);
+ EXPECT_EQ(countl_one(static_cast<uint8_t>(-1)), 8);
+ EXPECT_EQ(countl_one(uint16_t{}), 0);
+ EXPECT_EQ(countl_one(static_cast<uint16_t>(-1)), 16);
+ EXPECT_EQ(countl_one(uint32_t{}), 0);
+ EXPECT_EQ(countl_one(~uint32_t{}), 32);
+ EXPECT_EQ(countl_one(uint64_t{}), 0);
+ EXPECT_EQ(countl_one(~uint64_t{}), 64);
+}
+
+TEST(Counting, TrailingZeroes) {
+#if ABSL_INTERNAL_HAS_CONSTEXPR_CTZ
+ static_assert(countr_zero(uint8_t{}) == 8, "");
+ static_assert(countr_zero(static_cast<uint8_t>(-1)) == 0, "");
+ static_assert(countr_zero(uint16_t{}) == 16, "");
+ static_assert(countr_zero(static_cast<uint16_t>(-1)) == 0, "");
+ static_assert(countr_zero(uint32_t{}) == 32, "");
+ static_assert(countr_zero(~uint32_t{}) == 0, "");
+ static_assert(countr_zero(uint64_t{}) == 64, "");
+ static_assert(countr_zero(~uint64_t{}) == 0, "");
+#endif
+
+ EXPECT_EQ(countr_zero(uint8_t{}), 8);
+ EXPECT_EQ(countr_zero(static_cast<uint8_t>(-1)), 0);
+ EXPECT_EQ(countr_zero(uint16_t{}), 16);
+ EXPECT_EQ(countr_zero(static_cast<uint16_t>(-1)), 0);
+ EXPECT_EQ(countr_zero(uint32_t{}), 32);
+ EXPECT_EQ(countr_zero(~uint32_t{}), 0);
+ EXPECT_EQ(countr_zero(uint64_t{}), 64);
+ EXPECT_EQ(countr_zero(~uint64_t{}), 0);
+}
+
+TEST(Counting, TrailingOnes) {
+#if ABSL_INTERNAL_HAS_CONSTEXPR_CTZ
+ static_assert(countr_one(uint8_t{}) == 0, "");
+ static_assert(countr_one(static_cast<uint8_t>(-1)) == 8, "");
+ static_assert(countr_one(uint16_t{}) == 0, "");
+ static_assert(countr_one(static_cast<uint16_t>(-1)) == 16, "");
+ static_assert(countr_one(uint32_t{}) == 0, "");
+ static_assert(countr_one(~uint32_t{}) == 32, "");
+ static_assert(countr_one(uint64_t{}) == 0, "");
+ static_assert(countr_one(~uint64_t{}) == 64, "");
+#endif
+
+ EXPECT_EQ(countr_one(uint8_t{}), 0);
+ EXPECT_EQ(countr_one(static_cast<uint8_t>(-1)), 8);
+ EXPECT_EQ(countr_one(uint16_t{}), 0);
+ EXPECT_EQ(countr_one(static_cast<uint16_t>(-1)), 16);
+ EXPECT_EQ(countr_one(uint32_t{}), 0);
+ EXPECT_EQ(countr_one(~uint32_t{}), 32);
+ EXPECT_EQ(countr_one(uint64_t{}), 0);
+ EXPECT_EQ(countr_one(~uint64_t{}), 64);
+}
+
+TEST(Counting, Popcount) {
+#if ABSL_INTERNAL_HAS_CONSTEXPR_POPCOUNT
+ static_assert(popcount(uint8_t{}) == 0, "");
+ static_assert(popcount(uint8_t{1}) == 1, "");
+ static_assert(popcount(static_cast<uint8_t>(-1)) == 8, "");
+ static_assert(popcount(uint16_t{}) == 0, "");
+ static_assert(popcount(uint16_t{1}) == 1, "");
+ static_assert(popcount(static_cast<uint16_t>(-1)) == 16, "");
+ static_assert(popcount(uint32_t{}) == 0, "");
+ static_assert(popcount(uint32_t{1}) == 1, "");
+ static_assert(popcount(~uint32_t{}) == 32, "");
+ static_assert(popcount(uint64_t{}) == 0, "");
+ static_assert(popcount(uint64_t{1}) == 1, "");
+ static_assert(popcount(~uint64_t{}) == 64, "");
+#endif // ABSL_INTERNAL_HAS_CONSTEXPR_POPCOUNT
+
+ EXPECT_EQ(popcount(uint8_t{}), 0);
+ EXPECT_EQ(popcount(uint8_t{1}), 1);
+ EXPECT_EQ(popcount(static_cast<uint8_t>(-1)), 8);
+ EXPECT_EQ(popcount(uint16_t{}), 0);
+ EXPECT_EQ(popcount(uint16_t{1}), 1);
+ EXPECT_EQ(popcount(static_cast<uint16_t>(-1)), 16);
+ EXPECT_EQ(popcount(uint32_t{}), 0);
+ EXPECT_EQ(popcount(uint32_t{1}), 1);
+ EXPECT_EQ(popcount(~uint32_t{}), 32);
+ EXPECT_EQ(popcount(uint64_t{}), 0);
+ EXPECT_EQ(popcount(uint64_t{1}), 1);
+ EXPECT_EQ(popcount(~uint64_t{}), 64);
+
+ for (int i = 0; i < 8; i++) {
+ EXPECT_EQ(popcount(static_cast<uint8_t>(uint8_t{1} << i)), 1);
+ EXPECT_EQ(popcount(static_cast<uint8_t>(static_cast<uint8_t>(-1) ^
+ (uint8_t{1} << i))),
+ 7);
+ }
+
+ for (int i = 0; i < 16; i++) {
+ EXPECT_EQ(popcount(static_cast<uint16_t>(uint16_t{1} << i)), 1);
+ EXPECT_EQ(popcount(static_cast<uint16_t>(static_cast<uint16_t>(-1) ^
+ (uint16_t{1} << i))),
+ 15);
+ }
+
+ for (int i = 0; i < 32; i++) {
+ EXPECT_EQ(popcount(uint32_t{1} << i), 1);
+ EXPECT_EQ(popcount(static_cast<uint32_t>(-1) ^ (uint32_t{1} << i)), 31);
+ }
+
+ for (int i = 0; i < 64; i++) {
+ EXPECT_EQ(popcount(uint64_t{1} << i), 1);
+ EXPECT_EQ(popcount(static_cast<uint64_t>(-1) ^ (uint64_t{1} << i)), 63);
+ }
+}
+
+template <typename T>
+struct PopcountInput {
+ T value = 0;
+ int expected = 0;
+};
+
+template <typename T>
+PopcountInput<T> GeneratePopcountInput(absl::BitGen& gen) {
+ PopcountInput<T> ret;
+ for (int i = 0; i < std::numeric_limits<T>::digits; i++) {
+ bool coin = absl::Bernoulli(gen, 0.2);
+ if (coin) {
+ ret.value |= T{1} << i;
+ ret.expected++;
+ }
+ }
+ return ret;
+}
+
+TEST(Counting, PopcountFuzz) {
+ absl::BitGen rng;
+ constexpr int kTrials = 100;
+
+ for (int i = 0; i < kTrials; ++i) {
+ auto input = GeneratePopcountInput<uint8_t>(rng);
+ EXPECT_EQ(popcount(input.value), input.expected);
+ }
+
+ for (int i = 0; i < kTrials; ++i) {
+ auto input = GeneratePopcountInput<uint16_t>(rng);
+ EXPECT_EQ(popcount(input.value), input.expected);
+ }
+
+ for (int i = 0; i < kTrials; ++i) {
+ auto input = GeneratePopcountInput<uint32_t>(rng);
+ EXPECT_EQ(popcount(input.value), input.expected);
+ }
+
+ for (int i = 0; i < kTrials; ++i) {
+ auto input = GeneratePopcountInput<uint64_t>(rng);
+ EXPECT_EQ(popcount(input.value), input.expected);
+ }
+}
+
+TEST(IntegralPowersOfTwo, SingleBit) {
+ EXPECT_FALSE(has_single_bit(uint8_t{}));
+ EXPECT_FALSE(has_single_bit(static_cast<uint8_t>(-1)));
+ EXPECT_FALSE(has_single_bit(uint16_t{}));
+ EXPECT_FALSE(has_single_bit(static_cast<uint16_t>(-1)));
+ EXPECT_FALSE(has_single_bit(uint32_t{}));
+ EXPECT_FALSE(has_single_bit(~uint32_t{}));
+ EXPECT_FALSE(has_single_bit(uint64_t{}));
+ EXPECT_FALSE(has_single_bit(~uint64_t{}));
+
+ static_assert(!has_single_bit(0u), "");
+ static_assert(has_single_bit(1u), "");
+ static_assert(has_single_bit(2u), "");
+ static_assert(!has_single_bit(3u), "");
+ static_assert(has_single_bit(4u), "");
+ static_assert(!has_single_bit(1337u), "");
+ static_assert(has_single_bit(65536u), "");
+ static_assert(has_single_bit(uint32_t{1} << 30), "");
+ static_assert(has_single_bit(uint64_t{1} << 42), "");
+
+ EXPECT_FALSE(has_single_bit(0u));
+ EXPECT_TRUE(has_single_bit(1u));
+ EXPECT_TRUE(has_single_bit(2u));
+ EXPECT_FALSE(has_single_bit(3u));
+ EXPECT_TRUE(has_single_bit(4u));
+ EXPECT_FALSE(has_single_bit(1337u));
+ EXPECT_TRUE(has_single_bit(65536u));
+ EXPECT_TRUE(has_single_bit(uint32_t{1} << 30));
+ EXPECT_TRUE(has_single_bit(uint64_t{1} << 42));
+
+ EXPECT_TRUE(has_single_bit(
+ static_cast<uint8_t>(std::numeric_limits<uint8_t>::max() / 2 + 1)));
+ EXPECT_TRUE(has_single_bit(
+ static_cast<uint16_t>(std::numeric_limits<uint16_t>::max() / 2 + 1)));
+ EXPECT_TRUE(has_single_bit(
+ static_cast<uint32_t>(std::numeric_limits<uint32_t>::max() / 2 + 1)));
+ EXPECT_TRUE(has_single_bit(
+ static_cast<uint64_t>(std::numeric_limits<uint64_t>::max() / 2 + 1)));
+}
+
+template <typename T, T arg, T = bit_ceil(arg)>
+bool IsBitCeilConstantExpression(int) {
+ return true;
+}
+template <typename T, T arg>
+bool IsBitCeilConstantExpression(char) {
+ return false;
+}
+
+TEST(IntegralPowersOfTwo, Ceiling) {
+#if ABSL_INTERNAL_HAS_CONSTEXPR_CLZ
+ static_assert(bit_ceil(0u) == 1, "");
+ static_assert(bit_ceil(1u) == 1, "");
+ static_assert(bit_ceil(2u) == 2, "");
+ static_assert(bit_ceil(3u) == 4, "");
+ static_assert(bit_ceil(4u) == 4, "");
+ static_assert(bit_ceil(1337u) == 2048, "");
+ static_assert(bit_ceil(65536u) == 65536, "");
+ static_assert(bit_ceil(65536u - 1337u) == 65536, "");
+ static_assert(bit_ceil(uint32_t{0x80000000}) == uint32_t{0x80000000}, "");
+ static_assert(bit_ceil(uint64_t{0x40000000000}) == uint64_t{0x40000000000},
+ "");
+ static_assert(
+ bit_ceil(uint64_t{0x8000000000000000}) == uint64_t{0x8000000000000000},
+ "");
+
+ EXPECT_TRUE((IsBitCeilConstantExpression<uint8_t, uint8_t{0x0}>(0)));
+ EXPECT_TRUE((IsBitCeilConstantExpression<uint8_t, uint8_t{0x80}>(0)));
+ EXPECT_FALSE((IsBitCeilConstantExpression<uint8_t, uint8_t{0x81}>(0)));
+ EXPECT_FALSE((IsBitCeilConstantExpression<uint8_t, uint8_t{0xff}>(0)));
+
+ EXPECT_TRUE((IsBitCeilConstantExpression<uint16_t, uint16_t{0x0}>(0)));
+ EXPECT_TRUE((IsBitCeilConstantExpression<uint16_t, uint16_t{0x8000}>(0)));
+ EXPECT_FALSE((IsBitCeilConstantExpression<uint16_t, uint16_t{0x8001}>(0)));
+ EXPECT_FALSE((IsBitCeilConstantExpression<uint16_t, uint16_t{0xffff}>(0)));
+
+ EXPECT_TRUE((IsBitCeilConstantExpression<uint32_t, uint32_t{0x0}>(0)));
+ EXPECT_TRUE((IsBitCeilConstantExpression<uint32_t, uint32_t{0x80000000}>(0)));
+ EXPECT_FALSE(
+ (IsBitCeilConstantExpression<uint32_t, uint32_t{0x80000001}>(0)));
+ EXPECT_FALSE(
+ (IsBitCeilConstantExpression<uint32_t, uint32_t{0xffffffff}>(0)));
+
+ EXPECT_TRUE((IsBitCeilConstantExpression<uint64_t, uint64_t{0x0}>(0)));
+ EXPECT_TRUE(
+ (IsBitCeilConstantExpression<uint64_t, uint64_t{0x8000000000000000}>(0)));
+ EXPECT_FALSE(
+ (IsBitCeilConstantExpression<uint64_t, uint64_t{0x8000000000000001}>(0)));
+ EXPECT_FALSE(
+ (IsBitCeilConstantExpression<uint64_t, uint64_t{0xffffffffffffffff}>(0)));
+#endif
+
+ EXPECT_EQ(bit_ceil(0u), 1);
+ EXPECT_EQ(bit_ceil(1u), 1);
+ EXPECT_EQ(bit_ceil(2u), 2);
+ EXPECT_EQ(bit_ceil(3u), 4);
+ EXPECT_EQ(bit_ceil(4u), 4);
+ EXPECT_EQ(bit_ceil(1337u), 2048);
+ EXPECT_EQ(bit_ceil(65536u), 65536);
+ EXPECT_EQ(bit_ceil(65536u - 1337u), 65536);
+ EXPECT_EQ(bit_ceil(uint64_t{0x40000000000}), uint64_t{0x40000000000});
+}
+
+TEST(IntegralPowersOfTwo, Floor) {
+#if ABSL_INTERNAL_HAS_CONSTEXPR_CLZ
+ static_assert(bit_floor(0u) == 0, "");
+ static_assert(bit_floor(1u) == 1, "");
+ static_assert(bit_floor(2u) == 2, "");
+ static_assert(bit_floor(3u) == 2, "");
+ static_assert(bit_floor(4u) == 4, "");
+ static_assert(bit_floor(1337u) == 1024, "");
+ static_assert(bit_floor(65536u) == 65536, "");
+ static_assert(bit_floor(65536u - 1337u) == 32768, "");
+ static_assert(bit_floor(uint64_t{0x40000000000}) == uint64_t{0x40000000000},
+ "");
+#endif
+
+ EXPECT_EQ(bit_floor(0u), 0);
+ EXPECT_EQ(bit_floor(1u), 1);
+ EXPECT_EQ(bit_floor(2u), 2);
+ EXPECT_EQ(bit_floor(3u), 2);
+ EXPECT_EQ(bit_floor(4u), 4);
+ EXPECT_EQ(bit_floor(1337u), 1024);
+ EXPECT_EQ(bit_floor(65536u), 65536);
+ EXPECT_EQ(bit_floor(65536u - 1337u), 32768);
+ EXPECT_EQ(bit_floor(uint64_t{0x40000000000}), uint64_t{0x40000000000});
+
+ for (int i = 0; i < 8; i++) {
+ uint8_t input = uint8_t{1} << i;
+ EXPECT_EQ(bit_floor(input), input);
+ if (i > 0) {
+ EXPECT_EQ(bit_floor(static_cast<uint8_t>(input + 1)), input);
+ }
+ }
+
+ for (int i = 0; i < 16; i++) {
+ uint16_t input = uint16_t{1} << i;
+ EXPECT_EQ(bit_floor(input), input);
+ if (i > 0) {
+ EXPECT_EQ(bit_floor(static_cast<uint16_t>(input + 1)), input);
+ }
+ }
+
+ for (int i = 0; i < 32; i++) {
+ uint32_t input = uint32_t{1} << i;
+ EXPECT_EQ(bit_floor(input), input);
+ if (i > 0) {
+ EXPECT_EQ(bit_floor(input + 1), input);
+ }
+ }
+
+ for (int i = 0; i < 64; i++) {
+ uint64_t input = uint64_t{1} << i;
+ EXPECT_EQ(bit_floor(input), input);
+ if (i > 0) {
+ EXPECT_EQ(bit_floor(input + 1), input);
+ }
+ }
+}
+
+TEST(IntegralPowersOfTwo, Width) {
+#if ABSL_INTERNAL_HAS_CONSTEXPR_CLZ
+ static_assert(bit_width(uint8_t{}) == 0, "");
+ static_assert(bit_width(uint8_t{1}) == 1, "");
+ static_assert(bit_width(uint8_t{3}) == 2, "");
+ static_assert(bit_width(static_cast<uint8_t>(-1)) == 8, "");
+ static_assert(bit_width(uint16_t{}) == 0, "");
+ static_assert(bit_width(uint16_t{1}) == 1, "");
+ static_assert(bit_width(uint16_t{3}) == 2, "");
+ static_assert(bit_width(static_cast<uint16_t>(-1)) == 16, "");
+ static_assert(bit_width(uint32_t{}) == 0, "");
+ static_assert(bit_width(uint32_t{1}) == 1, "");
+ static_assert(bit_width(uint32_t{3}) == 2, "");
+ static_assert(bit_width(~uint32_t{}) == 32, "");
+ static_assert(bit_width(uint64_t{}) == 0, "");
+ static_assert(bit_width(uint64_t{1}) == 1, "");
+ static_assert(bit_width(uint64_t{3}) == 2, "");
+ static_assert(bit_width(~uint64_t{}) == 64, "");
+#endif
+
+ EXPECT_EQ(bit_width(uint8_t{}), 0);
+ EXPECT_EQ(bit_width(uint8_t{1}), 1);
+ EXPECT_EQ(bit_width(uint8_t{3}), 2);
+ EXPECT_EQ(bit_width(static_cast<uint8_t>(-1)), 8);
+ EXPECT_EQ(bit_width(uint16_t{}), 0);
+ EXPECT_EQ(bit_width(uint16_t{1}), 1);
+ EXPECT_EQ(bit_width(uint16_t{3}), 2);
+ EXPECT_EQ(bit_width(static_cast<uint16_t>(-1)), 16);
+ EXPECT_EQ(bit_width(uint32_t{}), 0);
+ EXPECT_EQ(bit_width(uint32_t{1}), 1);
+ EXPECT_EQ(bit_width(uint32_t{3}), 2);
+ EXPECT_EQ(bit_width(~uint32_t{}), 32);
+ EXPECT_EQ(bit_width(uint64_t{}), 0);
+ EXPECT_EQ(bit_width(uint64_t{1}), 1);
+ EXPECT_EQ(bit_width(uint64_t{3}), 2);
+ EXPECT_EQ(bit_width(~uint64_t{}), 64);
+
+ for (int i = 0; i < 8; i++) {
+ EXPECT_EQ(bit_width(static_cast<uint8_t>(uint8_t{1} << i)), i + 1);
+ }
+
+ for (int i = 0; i < 16; i++) {
+ EXPECT_EQ(bit_width(static_cast<uint16_t>(uint16_t{1} << i)), i + 1);
+ }
+
+ for (int i = 0; i < 32; i++) {
+ EXPECT_EQ(bit_width(uint32_t{1} << i), i + 1);
+ }
+
+ for (int i = 0; i < 64; i++) {
+ EXPECT_EQ(bit_width(uint64_t{1} << i), i + 1);
+ }
+}
+
+} // namespace
+ABSL_NAMESPACE_END
+} // namespace absl
