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-rw-r--r--absl/base/CMakeLists.txt6
-rw-r--r--absl/base/internal/sysinfo_test.cc23
-rw-r--r--absl/container/CMakeLists.txt2
-rw-r--r--absl/container/internal/inlined_vector.h11
-rw-r--r--absl/debugging/internal/stacktrace_config.h15
-rw-r--r--absl/numeric/BUILD.bazel29
-rw-r--r--absl/numeric/CMakeLists.txt29
-rw-r--r--absl/numeric/bits.h177
-rw-r--r--absl/numeric/bits_test.cc565
-rw-r--r--absl/numeric/internal/bits.h350
-rw-r--r--absl/random/CMakeLists.txt10
-rw-r--r--absl/strings/CMakeLists.txt4
-rw-r--r--absl/strings/cord.cc45
-rw-r--r--absl/strings/cord.h30
-rw-r--r--absl/strings/internal/cord_internal.cc5
-rw-r--r--absl/strings/internal/cord_internal.h11
16 files changed, 1259 insertions, 53 deletions
diff --git a/absl/base/CMakeLists.txt b/absl/base/CMakeLists.txt
index 9ff5aa24..515d7b4e 100644
--- a/absl/base/CMakeLists.txt
+++ b/absl/base/CMakeLists.txt
@@ -520,7 +520,7 @@ absl_cc_test(
absl_cc_library(
NAME
- bits
+ internal_bits
HDRS
"internal/bits.h"
COPTS
@@ -532,13 +532,13 @@ absl_cc_library(
absl_cc_test(
NAME
- bits_test
+ internal_bits_test
SRCS
"internal/bits_test.cc"
COPTS
${ABSL_TEST_COPTS}
DEPS
- absl::bits
+ absl::internal_bits
gtest_main
)
diff --git a/absl/base/internal/sysinfo_test.cc b/absl/base/internal/sysinfo_test.cc
index fa8b88b1..5f9e45f6 100644
--- a/absl/base/internal/sysinfo_test.cc
+++ b/absl/base/internal/sysinfo_test.cc
@@ -37,17 +37,28 @@ TEST(SysinfoTest, NumCPUs) {
<< "NumCPUs() should not have the default value of 0";
}
+// Ensure that NominalCPUFrequency returns a reasonable value, or 1.00 on
+// platforms where the CPU frequency is not available through sysfs.
+//
+// POWER is particularly problematic here; some Linux kernels expose the CPU
+// frequency, while others do not. Since we can't predict a priori what a given
+// machine is going to do, just disable this test on POWER on Linux.
+#if !(defined(__linux) && (defined(__ppc64__) || defined(__PPC64__)))
TEST(SysinfoTest, NominalCPUFrequency) {
-#if !(defined(__aarch64__) && defined(__linux__)) && !defined(__EMSCRIPTEN__)
- EXPECT_GE(NominalCPUFrequency(), 1000.0)
- << "NominalCPUFrequency() did not return a reasonable value";
-#else
- // Aarch64 cannot read the CPU frequency from sysfs, so we get back 1.0.
- // Emscripten does not have a sysfs to read from at all.
+ // Linux only exposes the CPU frequency on certain architectures, and
+ // Emscripten doesn't expose it at all.
+#if defined(__linux__) && \
+ (defined(__aarch64__) || defined(__hppa__) || defined(__mips__) || \
+ defined(__riscv) || defined(__s390x__)) || \
+ defined(__EMSCRIPTEN__)
EXPECT_EQ(NominalCPUFrequency(), 1.0)
<< "CPU frequency detection was fixed! Please update unittest.";
+#else
+ EXPECT_GE(NominalCPUFrequency(), 1000.0)
+ << "NominalCPUFrequency() did not return a reasonable value";
#endif
}
+#endif
TEST(SysinfoTest, GetTID) {
EXPECT_EQ(GetTID(), GetTID()); // Basic compile and equality test.
diff --git a/absl/container/CMakeLists.txt b/absl/container/CMakeLists.txt
index eb202c45..7562f32d 100644
--- a/absl/container/CMakeLists.txt
+++ b/absl/container/CMakeLists.txt
@@ -665,7 +665,7 @@ absl_cc_library(
COPTS
${ABSL_DEFAULT_COPTS}
DEPS
- absl::bits
+ absl::internal_bits
absl::compressed_tuple
absl::config
absl::container_common
diff --git a/absl/container/internal/inlined_vector.h b/absl/container/internal/inlined_vector.h
index 502ea3dd..120849cd 100644
--- a/absl/container/internal/inlined_vector.h
+++ b/absl/container/internal/inlined_vector.h
@@ -33,6 +33,12 @@ namespace absl {
ABSL_NAMESPACE_BEGIN
namespace inlined_vector_internal {
+// GCC does not deal very well with the below code
+#if !defined(__clang__) && defined(__GNUC__)
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
+#endif
+
template <typename Iterator>
using IsAtLeastForwardIterator = std::is_convertible<
typename std::iterator_traits<Iterator>::iterator_category,
@@ -889,6 +895,11 @@ auto Storage<T, N, A>::Swap(Storage* other_storage_ptr) -> void {
swap(*GetAllocPtr(), *other_storage_ptr->GetAllocPtr());
}
+// End ignore "maybe-uninitialized"
+#if !defined(__clang__) && defined(__GNUC__)
+#pragma GCC diagnostic pop
+#endif
+
} // namespace inlined_vector_internal
ABSL_NAMESPACE_END
} // namespace absl
diff --git a/absl/debugging/internal/stacktrace_config.h b/absl/debugging/internal/stacktrace_config.h
index 90af8528..cca410d4 100644
--- a/absl/debugging/internal/stacktrace_config.h
+++ b/absl/debugging/internal/stacktrace_config.h
@@ -21,6 +21,8 @@
#ifndef ABSL_DEBUGGING_INTERNAL_STACKTRACE_CONFIG_H_
#define ABSL_DEBUGGING_INTERNAL_STACKTRACE_CONFIG_H_
+#include "absl/base/config.h"
+
#if defined(ABSL_STACKTRACE_INL_HEADER)
#error ABSL_STACKTRACE_INL_HEADER cannot be directly set
@@ -29,19 +31,8 @@
"absl/debugging/internal/stacktrace_win32-inl.inc"
#elif defined(__APPLE__)
+#ifdef ABSL_HAVE_THREAD_LOCAL
// Thread local support required for UnwindImpl.
-// Notes:
-// * Xcode's clang did not support `thread_local` until version 8, and
-// even then not for all iOS < 9.0.
-// * Xcode 9.3 started disallowing `thread_local` for 32-bit iOS simulator
-// targeting iOS 9.x.
-// * Xcode 10 moves the deployment target check for iOS < 9.0 to link time
-// making __has_feature unreliable there.
-//
-// Otherwise, `__has_feature` is only supported by Clang so it has be inside
-// `defined(__APPLE__)` check.
-#if __has_feature(cxx_thread_local) && \
- !(TARGET_OS_IPHONE && __IPHONE_OS_VERSION_MIN_REQUIRED < __IPHONE_9_0)
#define ABSL_STACKTRACE_INL_HEADER \
"absl/debugging/internal/stacktrace_generic-inl.inc"
#endif
diff --git a/absl/numeric/BUILD.bazel b/absl/numeric/BUILD.bazel
index f808f5da..fb782ef3 100644
--- a/absl/numeric/BUILD.bazel
+++ b/absl/numeric/BUILD.bazel
@@ -25,6 +25,35 @@ package(default_visibility = ["//visibility:public"])
licenses(["notice"])
cc_library(
+ name = "bits",
+ hdrs = [
+ "bits.h",
+ "internal/bits.h",
+ ],
+ copts = ABSL_DEFAULT_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ "//absl/base:config",
+ "//absl/base:core_headers",
+ ],
+)
+
+cc_test(
+ name = "bits_test",
+ size = "small",
+ srcs = [
+ "bits_test.cc",
+ ],
+ copts = ABSL_TEST_COPTS,
+ linkopts = ABSL_DEFAULT_LINKOPTS,
+ deps = [
+ ":bits",
+ "//absl/random",
+ "@com_google_googletest//:gtest_main",
+ ],
+)
+
+cc_library(
name = "int128",
srcs = [
"int128.cc",
diff --git a/absl/numeric/CMakeLists.txt b/absl/numeric/CMakeLists.txt
index 1e12d80f..77e3f5ee 100644
--- a/absl/numeric/CMakeLists.txt
+++ b/absl/numeric/CMakeLists.txt
@@ -16,6 +16,33 @@
absl_cc_library(
NAME
+ bits
+ HDRS
+ "bits.h"
+ "internal/bits.h"
+ COPTS
+ ${ABSL_DEFAULT_COPTS}
+ DEPS
+ absl::core_headers
+ PUBLIC
+)
+
+absl_cc_test(
+ NAME
+ bits_test
+ SRCS
+ "bits_test.cc"
+ COPTS
+ ${ABSL_TEST_COPTS}
+ DEPS
+ absl::bits
+ absl::core_headers
+ absl::random_random
+ gmock_main
+)
+
+absl_cc_library(
+ NAME
int128
HDRS
"int128.h"
@@ -26,9 +53,9 @@ absl_cc_library(
COPTS
${ABSL_DEFAULT_COPTS}
DEPS
- absl::bits
absl::config
absl::core_headers
+ absl::internal_bits
PUBLIC
)
diff --git a/absl/numeric/bits.h b/absl/numeric/bits.h
new file mode 100644
index 00000000..52013ad4
--- /dev/null
+++ b/absl/numeric/bits.h
@@ -0,0 +1,177 @@
+// 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.
+//
+// -----------------------------------------------------------------------------
+// File: bits.h
+// -----------------------------------------------------------------------------
+//
+// This file contains implementations of C++20's bitwise math functions, as
+// defined by:
+//
+// P0553R4:
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p0553r4.html
+// P0556R3:
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2018/p0556r3.html
+// P1355R2:
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2019/p1355r2.html
+// P1956R1:
+// http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2020/p1956r1.pdf
+//
+// When using a standard library that implements these functions, we use the
+// standard library's implementation.
+
+#ifndef ABSL_NUMERIC_BITS_H_
+#define ABSL_NUMERIC_BITS_H_
+
+#include <cstdint>
+#include <limits>
+#include <type_traits>
+
+#if (defined(__cpp_lib_int_pow2) && __cpp_lib_int_pow2 >= 202002L) || \
+ (defined(__cpp_lib_bitops) && __cpp_lib_bitops >= 201907L)
+#include <bit>
+#endif
+
+#include "absl/base/attributes.h"
+#include "absl/base/config.h"
+#include "absl/numeric/internal/bits.h"
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+
+#if !(defined(__cpp_lib_bitops) && __cpp_lib_bitops >= 201907L)
+// rotating
+template <class T>
+ABSL_MUST_USE_RESULT constexpr
+ typename std::enable_if<std::is_unsigned<T>::value, T>::type
+ rotl(T x, int s) noexcept {
+ return numeric_internal::RotateLeft(x, s);
+}
+
+template <class T>
+ABSL_MUST_USE_RESULT constexpr
+ typename std::enable_if<std::is_unsigned<T>::value, T>::type
+ rotr(T x, int s) noexcept {
+ return numeric_internal::RotateRight(x, s);
+}
+
+// Counting functions
+//
+// While these functions are typically constexpr, on some platforms, they may
+// not be marked as constexpr due to constraints of the compiler/available
+// intrinsics.
+template <class T>
+ABSL_INTERNAL_CONSTEXPR_CLZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, int>::type
+ countl_zero(T x) noexcept {
+ return numeric_internal::CountLeadingZeroes(x);
+}
+
+template <class T>
+ABSL_INTERNAL_CONSTEXPR_CLZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, int>::type
+ countl_one(T x) noexcept {
+ // Avoid integer promotion to a wider type
+ return countl_zero(static_cast<T>(~x));
+}
+
+template <class T>
+ABSL_INTERNAL_CONSTEXPR_CTZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, int>::type
+ countr_zero(T x) noexcept {
+ return numeric_internal::CountTrailingZeroes(x);
+}
+
+template <class T>
+ABSL_INTERNAL_CONSTEXPR_CTZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, int>::type
+ countr_one(T x) noexcept {
+ // Avoid integer promotion to a wider type
+ return countr_zero(static_cast<T>(~x));
+}
+
+template <class T>
+ABSL_INTERNAL_CONSTEXPR_POPCOUNT inline
+ typename std::enable_if<std::is_unsigned<T>::value, int>::type
+ popcount(T x) noexcept {
+ return numeric_internal::Popcount(x);
+}
+#else // defined(__cpp_lib_bitops) && __cpp_lib_bitops >= 201907L
+
+using std::countl_one;
+using std::countl_zero;
+using std::countr_one;
+using std::countr_zero;
+using std::popcount;
+using std::rotl;
+using std::rotr;
+
+#endif
+
+#if !(defined(__cpp_lib_int_pow2) && __cpp_lib_int_pow2 >= 202002L)
+// Returns: true if x is an integral power of two; false otherwise.
+template <class T>
+constexpr inline typename std::enable_if<std::is_unsigned<T>::value, bool>::type
+has_single_bit(T x) noexcept {
+ return x != 0 && (x & (x - 1)) == 0;
+}
+
+// Returns: If x == 0, 0; otherwise one plus the base-2 logarithm of x, with any
+// fractional part discarded.
+template <class T>
+ABSL_INTERNAL_CONSTEXPR_CLZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, T>::type
+ bit_width(T x) noexcept {
+ return std::numeric_limits<T>::digits - countl_zero(x);
+}
+
+// Returns: If x == 0, 0; otherwise the maximal value y such that
+// has_single_bit(y) is true and y <= x.
+template <class T>
+ABSL_INTERNAL_CONSTEXPR_CLZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, T>::type
+ bit_floor(T x) noexcept {
+ return x == 0 ? 0 : T{1} << (bit_width(x) - 1);
+}
+
+// Returns: N, where N is the smallest power of 2 greater than or equal to x.
+//
+// Preconditions: N is representable as a value of type T.
+template <class T>
+ABSL_INTERNAL_CONSTEXPR_CLZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, T>::type
+ bit_ceil(T x) {
+ // If T is narrower than unsigned, T{1} << bit_width will be promoted. We
+ // want to force it to wraparound so that bit_ceil of an invalid value are not
+ // core constant expressions.
+ //
+ // BitCeilNonPowerOf2 triggers an overflow in constexpr contexts if we would
+ // undergo promotion to unsigned but not fit the result into T without
+ // truncation.
+ return has_single_bit(x) ? T{1} << (bit_width(x) - 1)
+ : numeric_internal::BitCeilNonPowerOf2(x);
+}
+#else // defined(__cpp_lib_int_pow2) && __cpp_lib_int_pow2 >= 202002L
+
+using std::bit_ceil;
+using std::bit_floor;
+using std::bit_width;
+using std::has_single_bit;
+
+#endif
+
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_NUMERIC_BITS_H_
diff --git a/absl/numeric/bits_test.cc b/absl/numeric/bits_test.cc
new file mode 100644
index 00000000..8bf7bc9f
--- /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
diff --git a/absl/numeric/internal/bits.h b/absl/numeric/internal/bits.h
new file mode 100644
index 00000000..60478f52
--- /dev/null
+++ b/absl/numeric/internal/bits.h
@@ -0,0 +1,350 @@
+// 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.
+
+#ifndef ABSL_NUMERIC_INTERNAL_BITS_H_
+#define ABSL_NUMERIC_INTERNAL_BITS_H_
+
+#include <cstdint>
+#include <limits>
+#include <type_traits>
+
+// Clang on Windows has __builtin_clzll; otherwise we need to use the
+// windows intrinsic functions.
+#if defined(_MSC_VER) && !defined(__clang__)
+#include <intrin.h>
+#if defined(_M_X64)
+#pragma intrinsic(_BitScanReverse64)
+#pragma intrinsic(_BitScanForward64)
+#endif
+#pragma intrinsic(_BitScanReverse)
+#pragma intrinsic(_BitScanForward)
+#endif
+
+#include "absl/base/attributes.h"
+#include "absl/base/config.h"
+
+#if ABSL_HAVE_BUILTIN(__builtin_popcountl) && \
+ ABSL_HAVE_BUILTIN(__builtin_popcountll)
+#define ABSL_INTERNAL_CONSTEXPR_POPCOUNT constexpr
+#define ABSL_INTERNAL_HAS_CONSTEXPR_POPCOUNT 1
+#else
+#define ABSL_INTERNAL_CONSTEXPR_POPCOUNT
+#define ABSL_INTERNAL_HAS_CONSTEXPR_POPCOUNT 0
+#endif
+
+#if ABSL_HAVE_BUILTIN(__builtin_clz) && ABSL_HAVE_BUILTIN(__builtin_clzll)
+#define ABSL_INTERNAL_CONSTEXPR_CLZ constexpr
+#define ABSL_INTERNAL_HAS_CONSTEXPR_CLZ 1
+#else
+#define ABSL_INTERNAL_CONSTEXPR_CLZ
+#define ABSL_INTERNAL_HAS_CONSTEXPR_CLZ 0
+#endif
+
+#if ABSL_HAVE_BUILTIN(__builtin_ctz) && ABSL_HAVE_BUILTIN(__builtin_ctzll)
+#define ABSL_INTERNAL_CONSTEXPR_CTZ constexpr
+#define ABSL_INTERNAL_HAS_CONSTEXPR_CTZ 1
+#else
+#define ABSL_INTERNAL_CONSTEXPR_CTZ
+#define ABSL_INTERNAL_HAS_CONSTEXPR_CTZ 0
+#endif
+
+namespace absl {
+ABSL_NAMESPACE_BEGIN
+namespace numeric_internal {
+
+constexpr bool IsPowerOf2(unsigned int x) noexcept {
+ return x != 0 && (x & (x - 1)) == 0;
+}
+
+template <class T>
+ABSL_MUST_USE_RESULT ABSL_ATTRIBUTE_ALWAYS_INLINE constexpr T RotateRight(
+ T x, int s) noexcept {
+ static_assert(std::is_unsigned<T>::value, "T must be unsigned");
+ static_assert(IsPowerOf2(std::numeric_limits<T>::digits),
+ "T must have a power-of-2 size");
+
+ return static_cast<T>(x >> (s & (std::numeric_limits<T>::digits - 1))) |
+ static_cast<T>(x << ((-s) & (std::numeric_limits<T>::digits - 1)));
+}
+
+template <class T>
+ABSL_MUST_USE_RESULT ABSL_ATTRIBUTE_ALWAYS_INLINE constexpr T RotateLeft(
+ T x, int s) noexcept {
+ static_assert(std::is_unsigned<T>::value, "T must be unsigned");
+ static_assert(IsPowerOf2(std::numeric_limits<T>::digits),
+ "T must have a power-of-2 size");
+
+ return static_cast<T>(x << (s & (std::numeric_limits<T>::digits - 1))) |
+ static_cast<T>(x >> ((-s) & (std::numeric_limits<T>::digits - 1)));
+}
+
+ABSL_INTERNAL_CONSTEXPR_POPCOUNT int Popcount32(uint32_t x) noexcept {
+#if ABSL_HAVE_BUILTIN(__builtin_popcount)
+ static_assert(sizeof(unsigned int) == sizeof(x),
+ "__builtin_popcount does not take 32-bit arg");
+ return __builtin_popcount(x);
+#else
+ x -= ((x >> 1) & 0x55555555);
+ x = ((x >> 2) & 0x33333333) + (x & 0x33333333);
+ return static_cast<int>((((x + (x >> 4)) & 0xF0F0F0F) * 0x1010101) >> 24);
+#endif
+}
+
+ABSL_INTERNAL_CONSTEXPR_POPCOUNT int Popcount64(uint64_t x) noexcept {
+#if ABSL_HAVE_BUILTIN(__builtin_popcountll)
+ static_assert(sizeof(unsigned long long) == sizeof(x), // NOLINT(runtime/int)
+ "__builtin_popcount does not take 64-bit arg");
+ return __builtin_popcountll(x);
+#else
+ x -= (x >> 1) & 0x5555555555555555ULL;
+ x = ((x >> 2) & 0x3333333333333333ULL) + (x & 0x3333333333333333ULL);
+ return static_cast<int>(
+ (((x + (x >> 4)) & 0xF0F0F0F0F0F0F0FULL) * 0x101010101010101ULL) >> 56);
+#endif
+}
+
+template <class T>
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_POPCOUNT inline int
+Popcount(T x) noexcept {
+ static_assert(std::is_unsigned<T>::value, "T must be unsigned");
+ static_assert(IsPowerOf2(std::numeric_limits<T>::digits),
+ "T must have a power-of-2 size");
+ static_assert(sizeof(x) <= sizeof(uint64_t), "T is too large");
+ return sizeof(x) <= sizeof(uint32_t) ? Popcount32(x) : Popcount64(x);
+}
+
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CLZ inline int
+CountLeadingZeroes32(uint32_t x) {
+#if ABSL_HAVE_BUILTIN(__builtin_clz)
+ // Use __builtin_clz, which uses the following instructions:
+ // x86: bsr, lzcnt
+ // ARM64: clz
+ // PPC: cntlzd
+
+ static_assert(sizeof(unsigned int) == sizeof(x),
+ "__builtin_clz does not take 32-bit arg");
+ // Handle 0 as a special case because __builtin_clz(0) is undefined.
+ return x == 0 ? 32 : __builtin_clz(x);
+#elif defined(_MSC_VER) && !defined(__clang__)
+ unsigned long result = 0; // NOLINT(runtime/int)
+ if (_BitScanReverse(&result, x)) {
+ return 31 - result;
+ }
+ return 32;
+#else
+ int zeroes = 28;
+ if (x >> 16) {
+ zeroes -= 16;
+ x >>= 16;
+ }
+ if (x >> 8) {
+ zeroes -= 8;
+ x >>= 8;
+ }
+ if (x >> 4) {
+ zeroes -= 4;
+ x >>= 4;
+ }
+ return "\4\3\2\2\1\1\1\1\0\0\0\0\0\0\0"[x] + zeroes;
+#endif
+}
+
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CLZ inline int
+CountLeadingZeroes16(uint16_t x) {
+#if ABSL_HAVE_BUILTIN(__builtin_clzs)
+ static_assert(sizeof(unsigned short) == sizeof(x), // NOLINT(runtime/int)
+ "__builtin_clzs does not take 16-bit arg");
+ return x == 0 ? 16 : __builtin_clzs(x);
+#else
+ return CountLeadingZeroes32(x) - 16;
+#endif
+}
+
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CLZ inline int
+CountLeadingZeroes64(uint64_t x) {
+#if ABSL_HAVE_BUILTIN(__builtin_clzll)
+ // Use __builtin_clzll, which uses the following instructions:
+ // x86: bsr, lzcnt
+ // ARM64: clz
+ // PPC: cntlzd
+ static_assert(sizeof(unsigned long long) == sizeof(x), // NOLINT(runtime/int)
+ "__builtin_clzll does not take 64-bit arg");
+
+ // Handle 0 as a special case because __builtin_clzll(0) is undefined.
+ return x == 0 ? 64 : __builtin_clzll(x);
+#elif defined(_MSC_VER) && !defined(__clang__) && defined(_M_X64)
+ // MSVC does not have __buitin_clzll. Use _BitScanReverse64.
+ unsigned long result = 0; // NOLINT(runtime/int)
+ if (_BitScanReverse64(&result, x)) {
+ return 63 - result;
+ }
+ return 64;
+#elif defined(_MSC_VER) && !defined(__clang__)
+ // MSVC does not have __buitin_clzll. Compose two calls to _BitScanReverse
+ unsigned long result = 0; // NOLINT(runtime/int)
+ if ((x >> 32) &&
+ _BitScanReverse(&result, static_cast<unsigned long>(x >> 32))) {
+ return 31 - result;
+ }
+ if (_BitScanReverse(&result, static_cast<unsigned long>(x))) {
+ return 63 - result;
+ }
+ return 64;
+#else
+ int zeroes = 60;
+ if (x >> 32) {
+ zeroes -= 32;
+ x >>= 32;
+ }
+ if (x >> 16) {
+ zeroes -= 16;
+ x >>= 16;
+ }
+ if (x >> 8) {
+ zeroes -= 8;
+ x >>= 8;
+ }
+ if (x >> 4) {
+ zeroes -= 4;
+ x >>= 4;
+ }
+ return "\4\3\2\2\1\1\1\1\0\0\0\0\0\0\0"[x] + zeroes;
+#endif
+}
+
+template <typename T>
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CLZ inline int
+CountLeadingZeroes(T x) {
+ static_assert(std::is_unsigned<T>::value, "T must be unsigned");
+ static_assert(IsPowerOf2(std::numeric_limits<T>::digits),
+ "T must have a power-of-2 size");
+ static_assert(sizeof(T) <= sizeof(uint64_t), "T too large");
+ return sizeof(T) <= sizeof(uint16_t)
+ ? CountLeadingZeroes16(x) -
+ (std::numeric_limits<uint16_t>::digits -
+ std::numeric_limits<T>::digits)
+ : (sizeof(T) <= sizeof(uint32_t)
+ ? CountLeadingZeroes32(x) -
+ (std::numeric_limits<uint32_t>::digits -
+ std::numeric_limits<T>::digits)
+ : CountLeadingZeroes64(x));
+}
+
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CTZ inline int
+CountTrailingZeroesNonzero32(uint32_t x) {
+#if ABSL_HAVE_BUILTIN(__builtin_ctz)
+ static_assert(sizeof(unsigned int) == sizeof(x),
+ "__builtin_ctz does not take 32-bit arg");
+ return __builtin_ctz(x);
+#elif defined(_MSC_VER) && !defined(__clang__)
+ unsigned long result = 0; // NOLINT(runtime/int)
+ _BitScanForward(&result, x);
+ return result;
+#else
+ int c = 31;
+ x &= ~x + 1;
+ if (x & 0x0000FFFF) c -= 16;
+ if (x & 0x00FF00FF) c -= 8;
+ if (x & 0x0F0F0F0F) c -= 4;
+ if (x & 0x33333333) c -= 2;
+ if (x & 0x55555555) c -= 1;
+ return c;
+#endif
+}
+
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CTZ inline int
+CountTrailingZeroesNonzero64(uint64_t x) {
+#if ABSL_HAVE_BUILTIN(__builtin_ctzll)
+ static_assert(sizeof(unsigned long long) == sizeof(x), // NOLINT(runtime/int)
+ "__builtin_ctzll does not take 64-bit arg");
+ return __builtin_ctzll(x);
+#elif defined(_MSC_VER) && !defined(__clang__) && defined(_M_X64)
+ unsigned long result = 0; // NOLINT(runtime/int)
+ _BitScanForward64(&result, x);
+ return result;
+#elif defined(_MSC_VER) && !defined(__clang__)
+ unsigned long result = 0; // NOLINT(runtime/int)
+ if (static_cast<uint32_t>(x) == 0) {
+ _BitScanForward(&result, static_cast<unsigned long>(x >> 32));
+ return result + 32;
+ }
+ _BitScanForward(&result, static_cast<unsigned long>(x));
+ return result;
+#else
+ int c = 63;
+ x &= ~x + 1;
+ if (x & 0x00000000FFFFFFFF) c -= 32;
+ if (x & 0x0000FFFF0000FFFF) c -= 16;
+ if (x & 0x00FF00FF00FF00FF) c -= 8;
+ if (x & 0x0F0F0F0F0F0F0F0F) c -= 4;
+ if (x & 0x3333333333333333) c -= 2;
+ if (x & 0x5555555555555555) c -= 1;
+ return c;
+#endif
+}
+
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CTZ inline int
+CountTrailingZeroesNonzero16(uint16_t x) {
+#if ABSL_HAVE_BUILTIN(__builtin_ctzs)
+ static_assert(sizeof(unsigned short) == sizeof(x), // NOLINT(runtime/int)
+ "__builtin_ctzs does not take 16-bit arg");
+ return __builtin_ctzs(x);
+#else
+ return CountTrailingZeroesNonzero32(x);
+#endif
+}
+
+template <class T>
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CTZ inline int
+CountTrailingZeroes(T x) noexcept {
+ static_assert(std::is_unsigned<T>::value, "T must be unsigned");
+ static_assert(IsPowerOf2(std::numeric_limits<T>::digits),
+ "T must have a power-of-2 size");
+ static_assert(sizeof(T) <= sizeof(uint64_t), "T too large");
+ return x == 0 ? std::numeric_limits<T>::digits
+ : (sizeof(T) <= sizeof(uint16_t)
+ ? CountTrailingZeroesNonzero16(x)
+ : (sizeof(T) <= sizeof(uint32_t)
+ ? CountTrailingZeroesNonzero32(x)
+ : CountTrailingZeroesNonzero64(x)));
+}
+
+// If T is narrower than unsigned, T{1} << bit_width will be promoted. We
+// want to force it to wraparound so that bit_ceil of an invalid value are not
+// core constant expressions.
+template <class T>
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CLZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, T>::type
+ BitCeilPromotionHelper(T x, T promotion) {
+ return (T{1} << (x + promotion)) >> promotion;
+}
+
+template <class T>
+ABSL_ATTRIBUTE_ALWAYS_INLINE ABSL_INTERNAL_CONSTEXPR_CLZ inline
+ typename std::enable_if<std::is_unsigned<T>::value, T>::type
+ BitCeilNonPowerOf2(T x) {
+ // If T is narrower than unsigned, it undergoes promotion to unsigned when we
+ // shift. We calcualte the number of bits added by the wider type.
+ return BitCeilPromotionHelper(
+ static_cast<T>(std::numeric_limits<T>::digits - CountLeadingZeroes(x)),
+ T{sizeof(T) >= sizeof(unsigned) ? 0
+ : std::numeric_limits<unsigned>::digits -
+ std::numeric_limits<T>::digits});
+}
+
+} // namespace numeric_internal
+ABSL_NAMESPACE_END
+} // namespace absl
+
+#endif // ABSL_NUMERIC_INTERNAL_BITS_H_
diff --git a/absl/random/CMakeLists.txt b/absl/random/CMakeLists.txt
index 7d7bec83..d717a5ce 100644
--- a/absl/random/CMakeLists.txt
+++ b/absl/random/CMakeLists.txt
@@ -673,7 +673,7 @@ absl_cc_library(
LINKOPTS
${ABSL_DEFAULT_LINKOPTS}
DEPS
- absl::bits
+ absl::internal_bits
absl::random_internal_fastmath
absl::random_internal_traits
absl::type_traits
@@ -690,7 +690,7 @@ absl_cc_library(
LINKOPTS
${ABSL_DEFAULT_LINKOPTS}
DEPS
- absl::bits
+ absl::internal_bits
absl::config
absl::int128
)
@@ -706,7 +706,7 @@ absl_cc_library(
LINKOPTS
${ABSL_DEFAULT_LINKOPTS}
DEPS
- absl::bits
+ absl::internal_bits
)
# Internal-only target, do not depend on directly.
@@ -902,7 +902,7 @@ absl_cc_test(
LINKOPTS
${ABSL_DEFAULT_LINKOPTS}
DEPS
- absl::bits
+ absl::internal_bits
absl::flags
absl::random_internal_generate_real
gtest_main
@@ -1201,7 +1201,7 @@ absl_cc_test(
${ABSL_DEFAULT_LINKOPTS}
DEPS
absl::random_internal_wide_multiply
- absl::bits
+ absl::internal_bits
absl::int128
gtest_main
)
diff --git a/absl/strings/CMakeLists.txt b/absl/strings/CMakeLists.txt
index 54c10151..6cdab257 100644
--- a/absl/strings/CMakeLists.txt
+++ b/absl/strings/CMakeLists.txt
@@ -56,7 +56,7 @@ absl_cc_library(
DEPS
absl::strings_internal
absl::base
- absl::bits
+ absl::internal_bits
absl::config
absl::core_headers
absl::endian
@@ -406,7 +406,7 @@ absl_cc_library(
COPTS
${ABSL_DEFAULT_COPTS}
DEPS
- absl::bits
+ absl::internal_bits
absl::strings
absl::config
absl::core_headers
diff --git a/absl/strings/cord.cc b/absl/strings/cord.cc
index f475042c..f87f4882 100644
--- a/absl/strings/cord.cc
+++ b/absl/strings/cord.cc
@@ -1298,26 +1298,23 @@ void Cord::CopyToArraySlowPath(char* dst) const {
}
}
-Cord::ChunkIterator& Cord::ChunkIterator::operator++() {
- ABSL_HARDENING_ASSERT(bytes_remaining_ > 0 &&
- "Attempted to iterate past `end()`");
- assert(bytes_remaining_ >= current_chunk_.size());
- bytes_remaining_ -= current_chunk_.size();
-
- if (stack_of_right_children_.empty()) {
+Cord::ChunkIterator& Cord::ChunkIterator::AdvanceStack() {
+ assert(absl::holds_alternative<Stack>(context_));
+ auto& stack_of_right_children = absl::get<Stack>(context_);
+ if (stack_of_right_children.empty()) {
assert(!current_chunk_.empty()); // Called on invalid iterator.
// We have reached the end of the Cord.
return *this;
}
// Process the next node on the stack.
- CordRep* node = stack_of_right_children_.back();
- stack_of_right_children_.pop_back();
+ CordRep* node = stack_of_right_children.back();
+ stack_of_right_children.pop_back();
// Walk down the left branches until we hit a non-CONCAT node. Save the
// right children to the stack for subsequent traversal.
while (node->tag == CONCAT) {
- stack_of_right_children_.push_back(node->concat()->right);
+ stack_of_right_children.push_back(node->concat()->right);
node = node->concat()->left;
}
@@ -1360,6 +1357,8 @@ Cord Cord::ChunkIterator::AdvanceAndReadBytes(size_t n) {
}
return subcord;
}
+ assert(absl::holds_alternative<Stack>(context_));
+ auto& stack_of_right_children = absl::get<Stack>(context_);
if (n < current_chunk_.size()) {
// Range to read is a proper subrange of the current chunk.
assert(current_leaf_ != nullptr);
@@ -1388,13 +1387,13 @@ Cord Cord::ChunkIterator::AdvanceAndReadBytes(size_t n) {
// Process the next node(s) on the stack, reading whole subtrees depending on
// their length and how many bytes we are advancing.
CordRep* node = nullptr;
- while (!stack_of_right_children_.empty()) {
- node = stack_of_right_children_.back();
- stack_of_right_children_.pop_back();
+ while (!stack_of_right_children.empty()) {
+ node = stack_of_right_children.back();
+ stack_of_right_children.pop_back();
if (node->length > n) break;
// TODO(qrczak): This might unnecessarily recreate existing concat nodes.
// Avoiding that would need pretty complicated logic (instead of
- // current_leaf_, keep current_subtree_ which points to the highest node
+ // current_leaf, keep current_subtree_ which points to the highest node
// such that the current leaf can be found on the path of left children
// starting from current_subtree_; delay creating subnode while node is
// below current_subtree_; find the proper node along the path of left
@@ -1419,7 +1418,7 @@ Cord Cord::ChunkIterator::AdvanceAndReadBytes(size_t n) {
while (node->tag == CONCAT) {
if (node->concat()->left->length > n) {
// Push right, descend left.
- stack_of_right_children_.push_back(node->concat()->right);
+ stack_of_right_children.push_back(node->concat()->right);
node = node->concat()->left;
} else {
// Read left, descend right.
@@ -1462,12 +1461,20 @@ void Cord::ChunkIterator::AdvanceBytesSlowPath(size_t n) {
n -= current_chunk_.size();
bytes_remaining_ -= current_chunk_.size();
+ if (!absl::holds_alternative<Stack>(context_)) {
+ // We have reached the end of the Cord.
+ assert(bytes_remaining_ == 0);
+ return;
+ }
+
// Process the next node(s) on the stack, skipping whole subtrees depending on
// their length and how many bytes we are advancing.
CordRep* node = nullptr;
- while (!stack_of_right_children_.empty()) {
- node = stack_of_right_children_.back();
- stack_of_right_children_.pop_back();
+ assert(absl::holds_alternative<Stack>(context_));
+ auto& stack_of_right_children = absl::get<Stack>(context_);
+ while (!stack_of_right_children.empty()) {
+ node = stack_of_right_children.back();
+ stack_of_right_children.pop_back();
if (node->length > n) break;
n -= node->length;
bytes_remaining_ -= node->length;
@@ -1485,7 +1492,7 @@ void Cord::ChunkIterator::AdvanceBytesSlowPath(size_t n) {
while (node->tag == CONCAT) {
if (node->concat()->left->length > n) {
// Push right, descend left.
- stack_of_right_children_.push_back(node->concat()->right);
+ stack_of_right_children.push_back(node->concat()->right);
node = node->concat()->left;
} else {
// Skip left, descend right.
diff --git a/absl/strings/cord.h b/absl/strings/cord.h
index b9cdc435..5fc61a73 100644
--- a/absl/strings/cord.h
+++ b/absl/strings/cord.h
@@ -362,6 +362,8 @@ class Cord {
friend class CharIterator;
private:
+ using Stack = absl::InlinedVector<absl::cord_internal::CordRep*, 4>;
+
// Constructs a `begin()` iterator from `cord`.
explicit ChunkIterator(const Cord* cord);
@@ -370,6 +372,10 @@ class Cord {
void RemoveChunkPrefix(size_t n);
Cord AdvanceAndReadBytes(size_t n);
void AdvanceBytes(size_t n);
+
+ // Stack specific operator++
+ ChunkIterator& AdvanceStack();
+
// Iterates `n` bytes, where `n` is expected to be greater than or equal to
// `current_chunk_.size()`.
void AdvanceBytesSlowPath(size_t n);
@@ -383,8 +389,10 @@ class Cord {
absl::cord_internal::CordRep* current_leaf_ = nullptr;
// The number of bytes left in the `Cord` over which we are iterating.
size_t bytes_remaining_ = 0;
- absl::InlinedVector<absl::cord_internal::CordRep*, 4>
- stack_of_right_children_;
+ // Context of this chunk iterator, can be one of:
+ // - monostate: iterator holds only one chunk or is empty.
+ // - Stack : iterator holds a concat / substring tree
+ absl::variant<absl::monostate, Stack> context_;
};
// Cord::ChunkIterator::chunk_begin()
@@ -1100,13 +1108,29 @@ inline Cord::ChunkIterator::ChunkIterator(const Cord* cord)
: bytes_remaining_(cord->size()) {
if (cord->empty()) return;
if (cord->contents_.is_tree()) {
- stack_of_right_children_.push_back(cord->contents_.tree());
+ Stack& stack_of_right_children = context_.emplace<Stack>();
+ stack_of_right_children.push_back(cord->contents_.tree());
operator++();
} else {
current_chunk_ = absl::string_view(cord->contents_.data(), cord->size());
}
}
+inline Cord::ChunkIterator& Cord::ChunkIterator::operator++() {
+ ABSL_HARDENING_ASSERT(bytes_remaining_ > 0 &&
+ "Attempted to iterate past `end()`");
+ assert(bytes_remaining_ >= current_chunk_.size());
+ bytes_remaining_ -= current_chunk_.size();
+ if (bytes_remaining_ > 0) {
+ if (absl::holds_alternative<Stack>(context_)) {
+ return AdvanceStack();
+ }
+ } else {
+ current_chunk_ = {};
+ }
+ return *this;
+}
+
inline Cord::ChunkIterator Cord::ChunkIterator::operator++(int) {
ChunkIterator tmp(*this);
operator++();
diff --git a/absl/strings/internal/cord_internal.cc b/absl/strings/internal/cord_internal.cc
index 35f4d235..59f2e4d9 100644
--- a/absl/strings/internal/cord_internal.cc
+++ b/absl/strings/internal/cord_internal.cc
@@ -24,7 +24,10 @@ namespace absl {
ABSL_NAMESPACE_BEGIN
namespace cord_internal {
-ABSL_CONST_INIT std::atomic<bool> cord_ring_buffer_enabled(false);
+ABSL_CONST_INIT std::atomic<bool> cord_ring_buffer_enabled(
+ kCordEnableRingBufferDefault);
+ABSL_CONST_INIT std::atomic<bool> shallow_subcords_enabled(
+ kCordShallowSubcordsDefault);
void CordRep::Destroy(CordRep* rep) {
assert(rep != nullptr);
diff --git a/absl/strings/internal/cord_internal.h b/absl/strings/internal/cord_internal.h
index f1af8e6e..57e7046a 100644
--- a/absl/strings/internal/cord_internal.h
+++ b/absl/strings/internal/cord_internal.h
@@ -31,12 +31,23 @@ namespace absl {
ABSL_NAMESPACE_BEGIN
namespace cord_internal {
+// Default feature enable states for cord ring buffers
+enum CordFeatureDefaults {
+ kCordEnableRingBufferDefault = false,
+ kCordShallowSubcordsDefault = false
+};
+
extern std::atomic<bool> cord_ring_buffer_enabled;
+extern std::atomic<bool> shallow_subcords_enabled;
inline void enable_cord_ring_buffer(bool enable) {
cord_ring_buffer_enabled.store(enable, std::memory_order_relaxed);
}
+inline void enable_shallow_subcords(bool enable) {
+ shallow_subcords_enabled.store(enable, std::memory_order_relaxed);
+}
+
enum Constants {
// The inlined size to use with absl::InlinedVector.
//
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-19 15:50:17 +0000