tvl-depot/absl/hash/internal/hash.h

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// 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.
//
// -----------------------------------------------------------------------------
// File: hash.h
// -----------------------------------------------------------------------------
//
#ifndef ABSL_HASH_INTERNAL_HASH_H_
#define ABSL_HASH_INTERNAL_HASH_H_
#include <algorithm>
#include <array>
#include <cmath>
#include <cstring>
#include <deque>
#include <forward_list>
#include <functional>
#include <iterator>
#include <limits>
#include <list>
#include <map>
#include <memory>
#include <set>
#include <string>
#include <tuple>
#include <type_traits>
#include <utility>
#include <vector>
#include "absl/base/internal/endian.h"
#include "absl/base/port.h"
#include "absl/container/fixed_array.h"
#include "absl/meta/type_traits.h"
#include "absl/numeric/int128.h"
#include "absl/strings/string_view.h"
#include "absl/types/optional.h"
#include "absl/types/variant.h"
#include "absl/utility/utility.h"
#include "absl/hash/internal/city.h"
namespace absl {
Export of internal Abseil changes -- c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>: Remove a floating point division by zero test. This isn't testing behavior related to the library, and MSVC warns about it in opt mode. PiperOrigin-RevId: 285220804 -- 68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>: This CL introduces following changes to the class FlagImpl: * We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately. * CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now. * Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call. * We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced. PiperOrigin-RevId: 285132636 -- ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>: Change null-term* (and nul-term*) to NUL-term* in comments PiperOrigin-RevId: 285036610 -- 729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>: Use the Posix implementation of thread identity on MinGW. Some versions of MinGW suffer from thread_local bugs. PiperOrigin-RevId: 285022920 -- 39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>: Implementation detail change. Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil. PiperOrigin-RevId: 285012012 GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
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ABSL_NAMESPACE_BEGIN
namespace hash_internal {
Export of internal Abseil changes -- 074a799119ac881b8b8ce59ef7a3166d1aa025ac by Tom Manshreck <shreck@google.com>: nit: Add return info for StrCat PiperOrigin-RevId: 278647298 -- d58a2a39ab6f50266cc695506ba2e86bdb45d795 by Mark Barolak <mbar@google.com>: Stop suppressing no-nested-anon-types warnings because there aren't actually any warnings to suppress. PiperOrigin-RevId: 278440548 -- 445051bd280b9a6f608a8c80b3d7cafcc1377a03 by Abseil Team <absl-team@google.com>: ResetThreadIdentity does not need to clear identity->waiter_state. ResetThreadIdentity is only called by NewThreadIdentity. NewThreadIdentity is only called by CreateThreadIdentity. CreateThreadIdentity calls PerThreadSem::Init, which initializes identity->waiter_state, immediately after calling NewThreadIdentity. Therefore ResetThreadIdentity does not need to clear identity->waiter_state. PiperOrigin-RevId: 278429844 -- c2079b664d92be40d5e365abcca4e9b3505a75a6 by Abseil Team <absl-team@google.com>: Delete the f->header.magic check in LowLevelAlloc::Free(). The f->header.magic check in LowLevelAlloc::Free() is redundant, because AddToFreeList() will immediately perform the same check. Also fix a typo in the comment that documents the lock requirements for Next(). The comment should say "L >= arena->mu", which is equivalent to EXCLUSIVE_LOCKS_REQUIRED(arena->mu). NOTE: LowLevelAlloc::Free() performs the f->header.magic check without holding the arena lock. This may have caused the TSAN data race warning reported in bug 143697235. PiperOrigin-RevId: 278414140 -- 5534f35ce677165700117d868f51607ed1f0d73b by Greg Falcon <gfalcon@google.com>: Add an internal (unsupported) PiecewiseCombiner class to allow hashing buffers piecewise. PiperOrigin-RevId: 278388902 GitOrigin-RevId: 074a799119ac881b8b8ce59ef7a3166d1aa025ac Change-Id: I61734850cbbb01c7585e8c736a5bb56e416512a8
2019-11-05 18:49:15 +01:00
class PiecewiseCombiner;
// Internal detail: Large buffers are hashed in smaller chunks. This function
// returns the size of these chunks.
constexpr int PiecewiseChunkSize() { return 1024; }
// HashStateBase
//
// A hash state object represents an intermediate state in the computation
// of an unspecified hash algorithm. `HashStateBase` provides a CRTP style
// base class for hash state implementations. Developers adding type support
// for `absl::Hash` should not rely on any parts of the state object other than
// the following member functions:
//
// * HashStateBase::combine()
// * HashStateBase::combine_contiguous()
//
// A derived hash state class of type `H` must provide a static member function
// with a signature similar to the following:
//
// `static H combine_contiguous(H state, const unsigned char*, size_t)`.
//
Export of internal Abseil changes -- 074a799119ac881b8b8ce59ef7a3166d1aa025ac by Tom Manshreck <shreck@google.com>: nit: Add return info for StrCat PiperOrigin-RevId: 278647298 -- d58a2a39ab6f50266cc695506ba2e86bdb45d795 by Mark Barolak <mbar@google.com>: Stop suppressing no-nested-anon-types warnings because there aren't actually any warnings to suppress. PiperOrigin-RevId: 278440548 -- 445051bd280b9a6f608a8c80b3d7cafcc1377a03 by Abseil Team <absl-team@google.com>: ResetThreadIdentity does not need to clear identity->waiter_state. ResetThreadIdentity is only called by NewThreadIdentity. NewThreadIdentity is only called by CreateThreadIdentity. CreateThreadIdentity calls PerThreadSem::Init, which initializes identity->waiter_state, immediately after calling NewThreadIdentity. Therefore ResetThreadIdentity does not need to clear identity->waiter_state. PiperOrigin-RevId: 278429844 -- c2079b664d92be40d5e365abcca4e9b3505a75a6 by Abseil Team <absl-team@google.com>: Delete the f->header.magic check in LowLevelAlloc::Free(). The f->header.magic check in LowLevelAlloc::Free() is redundant, because AddToFreeList() will immediately perform the same check. Also fix a typo in the comment that documents the lock requirements for Next(). The comment should say "L >= arena->mu", which is equivalent to EXCLUSIVE_LOCKS_REQUIRED(arena->mu). NOTE: LowLevelAlloc::Free() performs the f->header.magic check without holding the arena lock. This may have caused the TSAN data race warning reported in bug 143697235. PiperOrigin-RevId: 278414140 -- 5534f35ce677165700117d868f51607ed1f0d73b by Greg Falcon <gfalcon@google.com>: Add an internal (unsupported) PiecewiseCombiner class to allow hashing buffers piecewise. PiperOrigin-RevId: 278388902 GitOrigin-RevId: 074a799119ac881b8b8ce59ef7a3166d1aa025ac Change-Id: I61734850cbbb01c7585e8c736a5bb56e416512a8
2019-11-05 18:49:15 +01:00
// `HashStateBase` will provide a complete implementation for a hash state
// object in terms of this method.
//
// Example:
//
// // Use CRTP to define your derived class.
// struct MyHashState : HashStateBase<MyHashState> {
// static H combine_contiguous(H state, const unsigned char*, size_t);
// using MyHashState::HashStateBase::combine;
// using MyHashState::HashStateBase::combine_contiguous;
// };
template <typename H>
class HashStateBase {
public:
// HashStateBase::combine()
//
// Combines an arbitrary number of values into a hash state, returning the
// updated state.
//
// Each of the value types `T` must be separately hashable by the Abseil
// hashing framework.
//
// NOTE:
//
// state = H::combine(std::move(state), value1, value2, value3);
//
// is guaranteed to produce the same hash expansion as:
//
// state = H::combine(std::move(state), value1);
// state = H::combine(std::move(state), value2);
// state = H::combine(std::move(state), value3);
template <typename T, typename... Ts>
static H combine(H state, const T& value, const Ts&... values);
static H combine(H state) { return state; }
// HashStateBase::combine_contiguous()
//
// Combines a contiguous array of `size` elements into a hash state, returning
// the updated state.
//
// NOTE:
//
// state = H::combine_contiguous(std::move(state), data, size);
//
// is NOT guaranteed to produce the same hash expansion as a for-loop (it may
// perform internal optimizations). If you need this guarantee, use the
// for-loop instead.
template <typename T>
static H combine_contiguous(H state, const T* data, size_t size);
Export of internal Abseil changes -- 074a799119ac881b8b8ce59ef7a3166d1aa025ac by Tom Manshreck <shreck@google.com>: nit: Add return info for StrCat PiperOrigin-RevId: 278647298 -- d58a2a39ab6f50266cc695506ba2e86bdb45d795 by Mark Barolak <mbar@google.com>: Stop suppressing no-nested-anon-types warnings because there aren't actually any warnings to suppress. PiperOrigin-RevId: 278440548 -- 445051bd280b9a6f608a8c80b3d7cafcc1377a03 by Abseil Team <absl-team@google.com>: ResetThreadIdentity does not need to clear identity->waiter_state. ResetThreadIdentity is only called by NewThreadIdentity. NewThreadIdentity is only called by CreateThreadIdentity. CreateThreadIdentity calls PerThreadSem::Init, which initializes identity->waiter_state, immediately after calling NewThreadIdentity. Therefore ResetThreadIdentity does not need to clear identity->waiter_state. PiperOrigin-RevId: 278429844 -- c2079b664d92be40d5e365abcca4e9b3505a75a6 by Abseil Team <absl-team@google.com>: Delete the f->header.magic check in LowLevelAlloc::Free(). The f->header.magic check in LowLevelAlloc::Free() is redundant, because AddToFreeList() will immediately perform the same check. Also fix a typo in the comment that documents the lock requirements for Next(). The comment should say "L >= arena->mu", which is equivalent to EXCLUSIVE_LOCKS_REQUIRED(arena->mu). NOTE: LowLevelAlloc::Free() performs the f->header.magic check without holding the arena lock. This may have caused the TSAN data race warning reported in bug 143697235. PiperOrigin-RevId: 278414140 -- 5534f35ce677165700117d868f51607ed1f0d73b by Greg Falcon <gfalcon@google.com>: Add an internal (unsupported) PiecewiseCombiner class to allow hashing buffers piecewise. PiperOrigin-RevId: 278388902 GitOrigin-RevId: 074a799119ac881b8b8ce59ef7a3166d1aa025ac Change-Id: I61734850cbbb01c7585e8c736a5bb56e416512a8
2019-11-05 18:49:15 +01:00
private:
friend class PiecewiseCombiner;
};
// is_uniquely_represented
//
// `is_uniquely_represented<T>` is a trait class that indicates whether `T`
// is uniquely represented.
//
// A type is "uniquely represented" if two equal values of that type are
// guaranteed to have the same bytes in their underlying storage. In other
// words, if `a == b`, then `memcmp(&a, &b, sizeof(T))` is guaranteed to be
// zero. This property cannot be detected automatically, so this trait is false
// by default, but can be specialized by types that wish to assert that they are
// uniquely represented. This makes them eligible for certain optimizations.
//
// If you have any doubt whatsoever, do not specialize this template.
// The default is completely safe, and merely disables some optimizations
// that will not matter for most types. Specializing this template,
// on the other hand, can be very hazardous.
//
// To be uniquely represented, a type must not have multiple ways of
// representing the same value; for example, float and double are not
// uniquely represented, because they have distinct representations for
// +0 and -0. Furthermore, the type's byte representation must consist
// solely of user-controlled data, with no padding bits and no compiler-
// controlled data such as vptrs or sanitizer metadata. This is usually
// very difficult to guarantee, because in most cases the compiler can
// insert data and padding bits at its own discretion.
//
// If you specialize this template for a type `T`, you must do so in the file
// that defines that type (or in this file). If you define that specialization
// anywhere else, `is_uniquely_represented<T>` could have different meanings
// in different places.
//
// The Enable parameter is meaningless; it is provided as a convenience,
// to support certain SFINAE techniques when defining specializations.
template <typename T, typename Enable = void>
struct is_uniquely_represented : std::false_type {};
// is_uniquely_represented<unsigned char>
//
// unsigned char is a synonym for "byte", so it is guaranteed to be
// uniquely represented.
template <>
struct is_uniquely_represented<unsigned char> : std::true_type {};
// is_uniquely_represented for non-standard integral types
//
// Integral types other than bool should be uniquely represented on any
// platform that this will plausibly be ported to.
template <typename Integral>
struct is_uniquely_represented<
Integral, typename std::enable_if<std::is_integral<Integral>::value>::type>
: std::true_type {};
// is_uniquely_represented<bool>
//
//
template <>
struct is_uniquely_represented<bool> : std::false_type {};
// hash_bytes()
//
// Convenience function that combines `hash_state` with the byte representation
// of `value`.
template <typename H, typename T>
H hash_bytes(H hash_state, const T& value) {
const unsigned char* start = reinterpret_cast<const unsigned char*>(&value);
return H::combine_contiguous(std::move(hash_state), start, sizeof(value));
}
Export of internal Abseil changes -- 074a799119ac881b8b8ce59ef7a3166d1aa025ac by Tom Manshreck <shreck@google.com>: nit: Add return info for StrCat PiperOrigin-RevId: 278647298 -- d58a2a39ab6f50266cc695506ba2e86bdb45d795 by Mark Barolak <mbar@google.com>: Stop suppressing no-nested-anon-types warnings because there aren't actually any warnings to suppress. PiperOrigin-RevId: 278440548 -- 445051bd280b9a6f608a8c80b3d7cafcc1377a03 by Abseil Team <absl-team@google.com>: ResetThreadIdentity does not need to clear identity->waiter_state. ResetThreadIdentity is only called by NewThreadIdentity. NewThreadIdentity is only called by CreateThreadIdentity. CreateThreadIdentity calls PerThreadSem::Init, which initializes identity->waiter_state, immediately after calling NewThreadIdentity. Therefore ResetThreadIdentity does not need to clear identity->waiter_state. PiperOrigin-RevId: 278429844 -- c2079b664d92be40d5e365abcca4e9b3505a75a6 by Abseil Team <absl-team@google.com>: Delete the f->header.magic check in LowLevelAlloc::Free(). The f->header.magic check in LowLevelAlloc::Free() is redundant, because AddToFreeList() will immediately perform the same check. Also fix a typo in the comment that documents the lock requirements for Next(). The comment should say "L >= arena->mu", which is equivalent to EXCLUSIVE_LOCKS_REQUIRED(arena->mu). NOTE: LowLevelAlloc::Free() performs the f->header.magic check without holding the arena lock. This may have caused the TSAN data race warning reported in bug 143697235. PiperOrigin-RevId: 278414140 -- 5534f35ce677165700117d868f51607ed1f0d73b by Greg Falcon <gfalcon@google.com>: Add an internal (unsupported) PiecewiseCombiner class to allow hashing buffers piecewise. PiperOrigin-RevId: 278388902 GitOrigin-RevId: 074a799119ac881b8b8ce59ef7a3166d1aa025ac Change-Id: I61734850cbbb01c7585e8c736a5bb56e416512a8
2019-11-05 18:49:15 +01:00
// PiecewiseCombiner
//
// PiecewiseCombiner is an internal-only helper class for hashing a piecewise
// buffer of `char` or `unsigned char` as though it were contiguous. This class
// provides two methods:
//
// H add_buffer(state, data, size)
// H finalize(state)
//
// `add_buffer` can be called zero or more times, followed by a single call to
// `finalize`. This will produce the same hash expansion as concatenating each
// buffer piece into a single contiguous buffer, and passing this to
// `H::combine_contiguous`.
//
// Example usage:
// PiecewiseCombiner combiner;
// for (const auto& piece : pieces) {
// state = combiner.add_buffer(std::move(state), piece.data, piece.size);
// }
// return combiner.finalize(std::move(state));
class PiecewiseCombiner {
public:
PiecewiseCombiner() : position_(0) {}
PiecewiseCombiner(const PiecewiseCombiner&) = delete;
PiecewiseCombiner& operator=(const PiecewiseCombiner&) = delete;
// PiecewiseCombiner::add_buffer()
//
// Appends the given range of bytes to the sequence to be hashed, which may
// modify the provided hash state.
template <typename H>
H add_buffer(H state, const unsigned char* data, size_t size);
template <typename H>
H add_buffer(H state, const char* data, size_t size) {
return add_buffer(std::move(state),
reinterpret_cast<const unsigned char*>(data), size);
}
// PiecewiseCombiner::finalize()
//
// Finishes combining the hash sequence, which may may modify the provided
// hash state.
//
// Once finalize() is called, add_buffer() may no longer be called. The
// resulting hash state will be the same as if the pieces passed to
// add_buffer() were concatenated into a single flat buffer, and then provided
// to H::combine_contiguous().
template <typename H>
H finalize(H state);
private:
unsigned char buf_[PiecewiseChunkSize()];
size_t position_;
};
// -----------------------------------------------------------------------------
// AbslHashValue for Basic Types
// -----------------------------------------------------------------------------
// Note: Default `AbslHashValue` implementations live in `hash_internal`. This
// allows us to block lexical scope lookup when doing an unqualified call to
// `AbslHashValue` below. User-defined implementations of `AbslHashValue` can
// only be found via ADL.
// AbslHashValue() for hashing bool values
//
// We use SFINAE to ensure that this overload only accepts bool, not types that
// are convertible to bool.
template <typename H, typename B>
typename std::enable_if<std::is_same<B, bool>::value, H>::type AbslHashValue(
H hash_state, B value) {
return H::combine(std::move(hash_state),
static_cast<unsigned char>(value ? 1 : 0));
}
// AbslHashValue() for hashing enum values
template <typename H, typename Enum>
typename std::enable_if<std::is_enum<Enum>::value, H>::type AbslHashValue(
H hash_state, Enum e) {
// In practice, we could almost certainly just invoke hash_bytes directly,
// but it's possible that a sanitizer might one day want to
// store data in the unused bits of an enum. To avoid that risk, we
// convert to the underlying type before hashing. Hopefully this will get
// optimized away; if not, we can reopen discussion with c-toolchain-team.
return H::combine(std::move(hash_state),
static_cast<typename std::underlying_type<Enum>::type>(e));
}
// AbslHashValue() for hashing floating-point values
template <typename H, typename Float>
typename std::enable_if<std::is_same<Float, float>::value ||
std::is_same<Float, double>::value,
H>::type
AbslHashValue(H hash_state, Float value) {
return hash_internal::hash_bytes(std::move(hash_state),
value == 0 ? 0 : value);
}
// Long double has the property that it might have extra unused bytes in it.
// For example, in x86 sizeof(long double)==16 but it only really uses 80-bits
// of it. This means we can't use hash_bytes on a long double and have to
// convert it to something else first.
template <typename H, typename LongDouble>
typename std::enable_if<std::is_same<LongDouble, long double>::value, H>::type
AbslHashValue(H hash_state, LongDouble value) {
const int category = std::fpclassify(value);
switch (category) {
case FP_INFINITE:
// Add the sign bit to differentiate between +Inf and -Inf
hash_state = H::combine(std::move(hash_state), std::signbit(value));
break;
case FP_NAN:
case FP_ZERO:
default:
// Category is enough for these.
break;
case FP_NORMAL:
case FP_SUBNORMAL:
// We can't convert `value` directly to double because this would have
// undefined behavior if the value is out of range.
// std::frexp gives us a value in the range (-1, -.5] or [.5, 1) that is
// guaranteed to be in range for `double`. The truncation is
// implementation defined, but that works as long as it is deterministic.
int exp;
auto mantissa = static_cast<double>(std::frexp(value, &exp));
hash_state = H::combine(std::move(hash_state), mantissa, exp);
}
return H::combine(std::move(hash_state), category);
}
// AbslHashValue() for hashing pointers
template <typename H, typename T>
H AbslHashValue(H hash_state, T* ptr) {
Export of internal Abseil changes. -- 3d20ce6cd6541579abecaba169d4b8716d511272 by Jon Cohen <cohenjon@google.com>: Only use LSAN for clang version >= 3.5. This should fix https://github.com/abseil/abseil-cpp/issues/244 PiperOrigin-RevId: 234675129 -- e15bd4ec7a81aa95cc3d09fa1e0e81d58ae478fb by Conrad Parker <conradparker@google.com>: Fix errors in apply() sample code The following changes are made: * Make the example method public. * Give the two user functions different names to avoid confusion about whether apply() can select the correct overload of a function based on its tuple argument (it can't). * Pass tuple2 to the second example apply() invocation, instead of passing its contents individually. * Fix a s/tuple/tuple3/ typo in the third example apply() invocation. PiperOrigin-RevId: 234223407 -- de0ed71e21bc76ddf9fe715fdbaef74cd0df95c7 by Abseil Team <absl-team@google.com>: First test if a macro is defined to avoid -Wundef. ABSL clients may need to compile their code with the -Wundef warning flag. It will be helpful if ABSL header files can be compiled without the -Wundef warning. How to avoid the -Wundef warning: If a macro may be undefined, we need to first test whether the macro is defined before testing its value. We can't rely on the C preprocessor rule that an undefined macro has the value 0L. PiperOrigin-RevId: 234201123 -- fa484ad7dae0cac21140a96662809ecb0ec8eb5d by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 234185697 -- d69b1baef681e27954b065375ecf9c2320463b2b by Samuel Benzaquen <sbenza@google.com>: Mix pointers more thoroughly. Some pointer alignments interact badly with the mixing constant. By mixing twice we reduce this problem. PiperOrigin-RevId: 234178401 -- 1041d0e474610f3a8fea0db90958857327d6da1c by Samuel Benzaquen <sbenza@google.com>: Record rehashes in the hashtablez struct. Only recording the probe length on insertion causes a huge overestimation of the total probe length at any given time. With natural growth, elements are inserted when the load factor is between (max load/2, max load). However, after a rehash the majority of elements are actually inserted when the load factor is less than max/2 and have a much lower average probe length. Also reset some values when the table is cleared. PiperOrigin-RevId: 234013580 -- 299205caf3c89c47339f7409bc831746602cea84 by Mark Barolak <mbar@google.com>: Fix a sample code snippet that assumes `absl::string_view::const_iterator` is `const char*`. This is generally true, however in C++17 builds, absl::string_view is an alias for std::string_view and on MSVC, the std::string_view::const_iterator is an object instead of just a pointer. PiperOrigin-RevId: 233844595 -- af6c6370cf51a1e6c1469c79dfb2a486a4009136 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 233773470 -- 6e59e4b8e2bb6101b448f0f32b0bea81fe399ccf by Abseil Team <absl-team@google.com>: fix typo in {Starts|Ends}WithIgnoreCase comment in match.h PiperOrigin-RevId: 233662951 GitOrigin-RevId: 3d20ce6cd6541579abecaba169d4b8716d511272 Change-Id: Ib9a29b1c38c6aedf5d9f3f7f00596e8d30e864dd
2019-02-19 23:29:09 +01:00
auto v = reinterpret_cast<uintptr_t>(ptr);
// Due to alignment, pointers tend to have low bits as zero, and the next few
// bits follow a pattern since they are also multiples of some base value.
// Mixing the pointer twice helps prevent stuck low bits for certain alignment
// values.
return H::combine(std::move(hash_state), v, v);
}
// AbslHashValue() for hashing nullptr_t
template <typename H>
H AbslHashValue(H hash_state, std::nullptr_t) {
return H::combine(std::move(hash_state), static_cast<void*>(nullptr));
}
// -----------------------------------------------------------------------------
// AbslHashValue for Composite Types
// -----------------------------------------------------------------------------
// is_hashable()
//
// Trait class which returns true if T is hashable by the absl::Hash framework.
// Used for the AbslHashValue implementations for composite types below.
template <typename T>
struct is_hashable;
// AbslHashValue() for hashing pairs
template <typename H, typename T1, typename T2>
typename std::enable_if<is_hashable<T1>::value && is_hashable<T2>::value,
H>::type
AbslHashValue(H hash_state, const std::pair<T1, T2>& p) {
return H::combine(std::move(hash_state), p.first, p.second);
}
// hash_tuple()
//
// Helper function for hashing a tuple. The third argument should
// be an index_sequence running from 0 to tuple_size<Tuple> - 1.
template <typename H, typename Tuple, size_t... Is>
H hash_tuple(H hash_state, const Tuple& t, absl::index_sequence<Is...>) {
return H::combine(std::move(hash_state), std::get<Is>(t)...);
}
// AbslHashValue for hashing tuples
template <typename H, typename... Ts>
Export of internal Abseil changes. -- 5f1ab09522226336830d9ea6ef7276d37f536ac5 by Abseil Team <absl-team@google.com>: Clarify the documentation of ABSL_MUST_USE_RESULT. PiperOrigin-RevId: 221663609 -- af4c8359a20d56369fd1dce318220cf3be03ca66 by Greg Falcon <gfalcon@google.com>: Internal change PiperOrigin-RevId: 221538448 -- 487cd09bd1942bf607080deeae38fee6ce66f294 by Eric Fiselier <ericwf@google.com>: Work around emscripten bugs and missing features in absl/time:time_test. The emscripten toolchain has a couple of issues that cause time_test to fail. Specifically: 1) emscripten doesn't support signals. 2) The javascript implementation of strftime/strptime use different expansions of '%c' that mean it doesn't round-trip. PiperOrigin-RevId: 221523701 -- 5823652e6a200b97b07334bc47128dfac40e20fc by Xiaoyi Zhang <zhangxy@google.com>: Fix MSVC compiler warning by explicitly casting to char. Currently our MSVC build breaks with the following error: raw_hash_set.h(406): warning C4309: 'argument': truncation of constant value PiperOrigin-RevId: 221492585 -- c5806358320711a5efbe5c523df13e14ab53a17d by Greg Falcon <gfalcon@google.com>: Replace calls to getpagesize() with the more portable sysconf(_SC_PAGESIZE); the latter is in POSIX 1.0 and is called out in the Linux `getpagesize` man page as a more portable spelling. PiperOrigin-RevId: 221492471 -- 19ffe82851072229bb7ce73f754ffe4c18e8c575 by Abseil Team <absl-team@google.com>: Fix -Wundef error in absl/hash/internal/hash.h. PiperOrigin-RevId: 221444120 -- b30f3d0a848563b6e4ec33f3dc085831dfabb748 by Jon Cohen <cohenjon@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 221339736 GitOrigin-RevId: 5f1ab09522226336830d9ea6ef7276d37f536ac5 Change-Id: I96223d522d98bf6616dea88eb047c2d536eeddd0
2018-11-15 20:55:00 +01:00
#if defined(_MSC_VER)
// This SFINAE gets MSVC confused under some conditions. Let's just disable it
// for now.
H
Export of internal Abseil changes. -- 5f1ab09522226336830d9ea6ef7276d37f536ac5 by Abseil Team <absl-team@google.com>: Clarify the documentation of ABSL_MUST_USE_RESULT. PiperOrigin-RevId: 221663609 -- af4c8359a20d56369fd1dce318220cf3be03ca66 by Greg Falcon <gfalcon@google.com>: Internal change PiperOrigin-RevId: 221538448 -- 487cd09bd1942bf607080deeae38fee6ce66f294 by Eric Fiselier <ericwf@google.com>: Work around emscripten bugs and missing features in absl/time:time_test. The emscripten toolchain has a couple of issues that cause time_test to fail. Specifically: 1) emscripten doesn't support signals. 2) The javascript implementation of strftime/strptime use different expansions of '%c' that mean it doesn't round-trip. PiperOrigin-RevId: 221523701 -- 5823652e6a200b97b07334bc47128dfac40e20fc by Xiaoyi Zhang <zhangxy@google.com>: Fix MSVC compiler warning by explicitly casting to char. Currently our MSVC build breaks with the following error: raw_hash_set.h(406): warning C4309: 'argument': truncation of constant value PiperOrigin-RevId: 221492585 -- c5806358320711a5efbe5c523df13e14ab53a17d by Greg Falcon <gfalcon@google.com>: Replace calls to getpagesize() with the more portable sysconf(_SC_PAGESIZE); the latter is in POSIX 1.0 and is called out in the Linux `getpagesize` man page as a more portable spelling. PiperOrigin-RevId: 221492471 -- 19ffe82851072229bb7ce73f754ffe4c18e8c575 by Abseil Team <absl-team@google.com>: Fix -Wundef error in absl/hash/internal/hash.h. PiperOrigin-RevId: 221444120 -- b30f3d0a848563b6e4ec33f3dc085831dfabb748 by Jon Cohen <cohenjon@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 221339736 GitOrigin-RevId: 5f1ab09522226336830d9ea6ef7276d37f536ac5 Change-Id: I96223d522d98bf6616dea88eb047c2d536eeddd0
2018-11-15 20:55:00 +01:00
#else // _MSC_VER
typename std::enable_if<absl::conjunction<is_hashable<Ts>...>::value, H>::type
Export of internal Abseil changes. -- 5f1ab09522226336830d9ea6ef7276d37f536ac5 by Abseil Team <absl-team@google.com>: Clarify the documentation of ABSL_MUST_USE_RESULT. PiperOrigin-RevId: 221663609 -- af4c8359a20d56369fd1dce318220cf3be03ca66 by Greg Falcon <gfalcon@google.com>: Internal change PiperOrigin-RevId: 221538448 -- 487cd09bd1942bf607080deeae38fee6ce66f294 by Eric Fiselier <ericwf@google.com>: Work around emscripten bugs and missing features in absl/time:time_test. The emscripten toolchain has a couple of issues that cause time_test to fail. Specifically: 1) emscripten doesn't support signals. 2) The javascript implementation of strftime/strptime use different expansions of '%c' that mean it doesn't round-trip. PiperOrigin-RevId: 221523701 -- 5823652e6a200b97b07334bc47128dfac40e20fc by Xiaoyi Zhang <zhangxy@google.com>: Fix MSVC compiler warning by explicitly casting to char. Currently our MSVC build breaks with the following error: raw_hash_set.h(406): warning C4309: 'argument': truncation of constant value PiperOrigin-RevId: 221492585 -- c5806358320711a5efbe5c523df13e14ab53a17d by Greg Falcon <gfalcon@google.com>: Replace calls to getpagesize() with the more portable sysconf(_SC_PAGESIZE); the latter is in POSIX 1.0 and is called out in the Linux `getpagesize` man page as a more portable spelling. PiperOrigin-RevId: 221492471 -- 19ffe82851072229bb7ce73f754ffe4c18e8c575 by Abseil Team <absl-team@google.com>: Fix -Wundef error in absl/hash/internal/hash.h. PiperOrigin-RevId: 221444120 -- b30f3d0a848563b6e4ec33f3dc085831dfabb748 by Jon Cohen <cohenjon@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 221339736 GitOrigin-RevId: 5f1ab09522226336830d9ea6ef7276d37f536ac5 Change-Id: I96223d522d98bf6616dea88eb047c2d536eeddd0
2018-11-15 20:55:00 +01:00
#endif // _MSC_VER
AbslHashValue(H hash_state, const std::tuple<Ts...>& t) {
return hash_internal::hash_tuple(std::move(hash_state), t,
absl::make_index_sequence<sizeof...(Ts)>());
}
// -----------------------------------------------------------------------------
// AbslHashValue for Pointers
// -----------------------------------------------------------------------------
// AbslHashValue for hashing unique_ptr
template <typename H, typename T, typename D>
H AbslHashValue(H hash_state, const std::unique_ptr<T, D>& ptr) {
return H::combine(std::move(hash_state), ptr.get());
}
// AbslHashValue for hashing shared_ptr
template <typename H, typename T>
H AbslHashValue(H hash_state, const std::shared_ptr<T>& ptr) {
return H::combine(std::move(hash_state), ptr.get());
}
// -----------------------------------------------------------------------------
// AbslHashValue for String-Like Types
// -----------------------------------------------------------------------------
// AbslHashValue for hashing strings
//
// All the string-like types supported here provide the same hash expansion for
// the same character sequence. These types are:
//
// - `std::string` (and std::basic_string<char, std::char_traits<char>, A> for
// any allocator A)
// - `absl::string_view` and `std::string_view`
//
// For simplicity, we currently support only `char` strings. This support may
// be broadened, if necessary, but with some caution - this overload would
// misbehave in cases where the traits' `eq()` member isn't equivalent to `==`
// on the underlying character type.
template <typename H>
H AbslHashValue(H hash_state, absl::string_view str) {
return H::combine(
H::combine_contiguous(std::move(hash_state), str.data(), str.size()),
str.size());
}
Export of internal Abseil changes -- 049ac45508e335c6f010f2d28d71016b9fa65b4e by Derek Mauro <dmauro@google.com>: Fix librt detection PiperOrigin-RevId: 280207723 -- 6382c3a9fb2643af9dc031f92ca846c4a78e249c by Andy Getzendanner <durandal@google.com>: Fix Conan builds Import of https://github.com/abseil/abseil-cpp/pull/400 PiperOrigin-RevId: 280025424 -- aebcd52b1686ac82663a8d0193b60d0122a43372 by Samuel Benzaquen <sbenza@google.com>: Enable the assertion in the iterator's operator== and operator!= PiperOrigin-RevId: 279998951 -- 5b61d909e2159ac6fd45e0e456818db1e725ecd1 by Derek Mauro <dmauro@google.com>: Add best effort support for compiling much of Abseil with MinGW. This involves disabling ABSL_ATTRIBUTE_WEAK and adding link flags. A change to CCTZ is still necessary. Tests were not run yet, but most of them now build. PiperOrigin-RevId: 279966541 -- 4336f8b10cff906e2defdd7d1d449cde4907da5d by Abseil Team <absl-team@google.com>: Add comments and relax memory orders in base_internal::CallOnceImpl. Add a comment to document the memory order guarantee if base_internal::SpinLockWait() is called and returns kOnceDone. Add a comment for the load/store sequence in base_internal::CallOnceImpl based on Mike Burrows' explanation. The atomic load of 'control' in the #ifndef NDEBUG block does not need std::memory_order_acquire. It can use std::memory_order_relaxed. The atomic compare_exchange_strong of 'control' does not need std::memory_order_acquire in the success case. It can use std::memory_order_relaxed. PiperOrigin-RevId: 279814155 -- 407de3a5e9af957cded54a136ca0468bde620d4d by Abseil Team <absl-team@google.com>: Added a script to generate abseil.podspec from all BUILD.bazel files automatically. PiperOrigin-RevId: 279811441 -- 26139497d4a363d6c7bc989c554da593e8819a07 by Derek Mauro <dmauro@google.com>: Add missing copyright and Apache License to //absl/functional/BUILD.bazel PiperOrigin-RevId: 279795227 -- 98ed625b02af6e5834edf52a920d8ca2dab4cd90 by Matt Kulukundis <kfm@google.com>: Switch the implementation of hashtablez to *only* work on platforms that have a PER_THREAD_TLS. The old case is very slow (global mutex) and nobody collects data from that configuration anyway. PiperOrigin-RevId: 279775149 -- 07225900ef672c005c38f467ad3f92f38d0922b3 by Derek Mauro <dmauro@google.com>: Remove the minumum glibc version check PiperOrigin-RevId: 279750412 -- ec09956a951b4f52228ecc81968b8db7ae19ed15 by Derek Mauro <dmauro@google.com>: CMake only: link with -lrt to support older glibc versions PiperOrigin-RevId: 279741661 -- 97b113fb2e8246f6152c36330ba13793b37154b6 by Xiaoyi Zhang <zhangxy@google.com>: Internal change. PiperOrigin-RevId: 279390188 -- ca8f72f2721546cc9b01bd01b2ea144962e6e0c5 by Andy Getzendanner <durandal@google.com>: Expose PutTwoDigits for internal use within Abseil. PiperOrigin-RevId: 279374239 -- 14c6384cc03bbdfdefd2e4b635f104af5dd7e026 by Derek Mauro <dmauro@google.com>: Remove log_severity sources from the base target. They are already compiled as part of a separate library. PiperOrigin-RevId: 279372619 -- 3c5d926c718f8bf394e3bee87b6ba8d94601e0d3 by Abseil Team <absl-team@google.com>: s/indepdent/independent/g in SimpleAtof's documentation. PiperOrigin-RevId: 279350836 -- de2c44be8a8edf9efa1fe2007cba3564f3e5b0b8 by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 279346990 -- 2ba078341423fcf6d0ba5ca1831f86570a26e615 by Samuel Benzaquen <sbenza@google.com>: Add hash support for std::wstring, std::u16string and std::u32string. PiperOrigin-RevId: 279320672 -- 3272d3ffcfa55283a04f90e5868701912da95ef7 by Andy Soffer <asoffer@google.com>: Removing a bunch of __restricts that amount to no performance differences. One of these is the cause of https://github.com/abseil/abseil-cpp/issues/396. In particular, in one of the Vector128Store functions, restricts on two pointers that were indeed aliased seems to be the root cause of the issues. Closes #396 PiperOrigin-RevId: 279318999 -- 342f338ab31cc24344d5de8f28cf455bbb629a17 by Jorg Brown <jorg@google.com>: Support uint128 in SimpleAtoi PiperOrigin-RevId: 279234038 -- 81cb0a04cf2dc4515d303679fc60968712191571 by Derek Mauro <dmauro@google.com>: Change the check for futex availability to support older Linux systems PiperOrigin-RevId: 279147079 -- cb4ca4aa4c8d2d710a5d483c56c4ce4f979e14b1 by Abseil Team <absl-team@google.com>: Add IWYU pragma: export for int128 .inc files. PiperOrigin-RevId: 279107098 -- b8df86ef610c366729f07326c726f3e34817b4dd by Abseil Team <absl-team@google.com>: An optimization for Waiter::Post() in the SEM waiter mode. Like the FUTEX waiter mode, Waiter::Post() only needs to call Poke() if it incremented the atomic variable from 0. PiperOrigin-RevId: 279086133 GitOrigin-RevId: 049ac45508e335c6f010f2d28d71016b9fa65b4e Change-Id: I4c1a4073fff62cb6a1fcb1c104aa7d62dad588c2
2019-11-13 17:54:32 +01:00
// Support std::wstring, std::u16string and std::u32string.
template <typename Char, typename Alloc, typename H,
typename = absl::enable_if_t<std::is_same<Char, wchar_t>::value ||
std::is_same<Char, char16_t>::value ||
std::is_same<Char, char32_t>::value>>
H AbslHashValue(
H hash_state,
const std::basic_string<Char, std::char_traits<Char>, Alloc>& str) {
return H::combine(
H::combine_contiguous(std::move(hash_state), str.data(), str.size()),
str.size());
}
// -----------------------------------------------------------------------------
// AbslHashValue for Sequence Containers
// -----------------------------------------------------------------------------
// AbslHashValue for hashing std::array
template <typename H, typename T, size_t N>
typename std::enable_if<is_hashable<T>::value, H>::type AbslHashValue(
H hash_state, const std::array<T, N>& array) {
return H::combine_contiguous(std::move(hash_state), array.data(),
array.size());
}
// AbslHashValue for hashing std::deque
template <typename H, typename T, typename Allocator>
typename std::enable_if<is_hashable<T>::value, H>::type AbslHashValue(
H hash_state, const std::deque<T, Allocator>& deque) {
// TODO(gromer): investigate a more efficient implementation taking
// advantage of the chunk structure.
for (const auto& t : deque) {
hash_state = H::combine(std::move(hash_state), t);
}
return H::combine(std::move(hash_state), deque.size());
}
// AbslHashValue for hashing std::forward_list
template <typename H, typename T, typename Allocator>
typename std::enable_if<is_hashable<T>::value, H>::type AbslHashValue(
H hash_state, const std::forward_list<T, Allocator>& list) {
size_t size = 0;
for (const T& t : list) {
hash_state = H::combine(std::move(hash_state), t);
++size;
}
return H::combine(std::move(hash_state), size);
}
// AbslHashValue for hashing std::list
template <typename H, typename T, typename Allocator>
typename std::enable_if<is_hashable<T>::value, H>::type AbslHashValue(
H hash_state, const std::list<T, Allocator>& list) {
for (const auto& t : list) {
hash_state = H::combine(std::move(hash_state), t);
}
return H::combine(std::move(hash_state), list.size());
}
// AbslHashValue for hashing std::vector
//
// Do not use this for vector<bool>. It does not have a .data(), and a fallback
// for std::hash<> is most likely faster.
template <typename H, typename T, typename Allocator>
typename std::enable_if<is_hashable<T>::value && !std::is_same<T, bool>::value,
H>::type
AbslHashValue(H hash_state, const std::vector<T, Allocator>& vector) {
return H::combine(H::combine_contiguous(std::move(hash_state), vector.data(),
vector.size()),
vector.size());
}
// -----------------------------------------------------------------------------
// AbslHashValue for Ordered Associative Containers
// -----------------------------------------------------------------------------
// AbslHashValue for hashing std::map
template <typename H, typename Key, typename T, typename Compare,
typename Allocator>
typename std::enable_if<is_hashable<Key>::value && is_hashable<T>::value,
H>::type
AbslHashValue(H hash_state, const std::map<Key, T, Compare, Allocator>& map) {
for (const auto& t : map) {
hash_state = H::combine(std::move(hash_state), t);
}
return H::combine(std::move(hash_state), map.size());
}
// AbslHashValue for hashing std::multimap
template <typename H, typename Key, typename T, typename Compare,
typename Allocator>
typename std::enable_if<is_hashable<Key>::value && is_hashable<T>::value,
H>::type
AbslHashValue(H hash_state,
const std::multimap<Key, T, Compare, Allocator>& map) {
for (const auto& t : map) {
hash_state = H::combine(std::move(hash_state), t);
}
return H::combine(std::move(hash_state), map.size());
}
// AbslHashValue for hashing std::set
template <typename H, typename Key, typename Compare, typename Allocator>
typename std::enable_if<is_hashable<Key>::value, H>::type AbslHashValue(
H hash_state, const std::set<Key, Compare, Allocator>& set) {
for (const auto& t : set) {
hash_state = H::combine(std::move(hash_state), t);
}
return H::combine(std::move(hash_state), set.size());
}
// AbslHashValue for hashing std::multiset
template <typename H, typename Key, typename Compare, typename Allocator>
typename std::enable_if<is_hashable<Key>::value, H>::type AbslHashValue(
H hash_state, const std::multiset<Key, Compare, Allocator>& set) {
for (const auto& t : set) {
hash_state = H::combine(std::move(hash_state), t);
}
return H::combine(std::move(hash_state), set.size());
}
// -----------------------------------------------------------------------------
// AbslHashValue for Wrapper Types
// -----------------------------------------------------------------------------
// AbslHashValue for hashing absl::optional
template <typename H, typename T>
typename std::enable_if<is_hashable<T>::value, H>::type AbslHashValue(
H hash_state, const absl::optional<T>& opt) {
if (opt) hash_state = H::combine(std::move(hash_state), *opt);
return H::combine(std::move(hash_state), opt.has_value());
}
// VariantVisitor
template <typename H>
struct VariantVisitor {
H&& hash_state;
template <typename T>
H operator()(const T& t) const {
return H::combine(std::move(hash_state), t);
}
};
// AbslHashValue for hashing absl::variant
template <typename H, typename... T>
typename std::enable_if<conjunction<is_hashable<T>...>::value, H>::type
AbslHashValue(H hash_state, const absl::variant<T...>& v) {
if (!v.valueless_by_exception()) {
hash_state = absl::visit(VariantVisitor<H>{std::move(hash_state)}, v);
}
return H::combine(std::move(hash_state), v.index());
}
// -----------------------------------------------------------------------------
// AbslHashValue for Other Types
// -----------------------------------------------------------------------------
// AbslHashValue for hashing std::bitset is not defined, for the same reason as
// for vector<bool> (see std::vector above): It does not expose the raw bytes,
// and a fallback to std::hash<> is most likely faster.
// -----------------------------------------------------------------------------
// hash_range_or_bytes()
//
// Mixes all values in the range [data, data+size) into the hash state.
// This overload accepts only uniquely-represented types, and hashes them by
// hashing the entire range of bytes.
template <typename H, typename T>
typename std::enable_if<is_uniquely_represented<T>::value, H>::type
hash_range_or_bytes(H hash_state, const T* data, size_t size) {
const auto* bytes = reinterpret_cast<const unsigned char*>(data);
return H::combine_contiguous(std::move(hash_state), bytes, sizeof(T) * size);
}
// hash_range_or_bytes()
template <typename H, typename T>
typename std::enable_if<!is_uniquely_represented<T>::value, H>::type
hash_range_or_bytes(H hash_state, const T* data, size_t size) {
for (const auto end = data + size; data < end; ++data) {
hash_state = H::combine(std::move(hash_state), *data);
}
return hash_state;
}
#if defined(ABSL_INTERNAL_LEGACY_HASH_NAMESPACE) && \
Export of internal Abseil changes. -- 6fdf24a197b964f9bacbebd0ceca305aef1654fc by Shaindel Schwartz <shaindel@google.com>: Internal change PiperOrigin-RevId: 231627312 -- 65f7faf52bff01384171efb85fee159378dedf70 by CJ Johnson <johnsoncj@google.com>: Relocates the definitions of the InputIterator-accepting parts of the InlinedVector API into the top-level. The removed functions had no other callers so there was no reason to keep the layer of indirection in the form of the function call. PiperOrigin-RevId: 231527459 -- 30e105b749b5ecc50fdaf26c7da589617efce425 by CJ Johnson <johnsoncj@google.com>: Relocates closing brace for absl namespace in InlinedVector to the correct end location PiperOrigin-RevId: 231477871 -- 063c1e8b9d1f032662c46d574e20ecc357b87d0c by Eric Fiselier <ericwf@google.com>: Cleanup std::hash probing metafunctions. Previously there were two different ways to probe for std::hash. One in hash.h and another in type_traits.h, and they were both implemented differently, and neither correctly worked around bad STL implementations. This patch unifies the implementations into a single IsHashable trait. It also: * Correctly checks for old libc++ versions where this won't work. * Avoids undefined behavior which resulted from calling std::is_constructible incomplete types. * Unifies the feature test macro used in the headers and the tests. Additionally it also slightly changes the behavior of when absl::variant is hashable. Previously we disable hashing when std::hash<T>()(key) was formed but when std::hash<T> couldn't be destructed. This seems wrong. If a user provides a evil specialization of std::hash, then it's OK for variant's hash to blow up. PiperOrigin-RevId: 231468345 -- 05d75dd4b07c893de9b104731644d0d207b01253 by Abseil Team <absl-team@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 231397518 -- a0ee9032f9e04039f3410ed17fcf45ae1a3868f5 by CJ Johnson <johnsoncj@google.com>: Remove unused EnableIfAtLeastInputIterator from InlinedVector PiperOrigin-RevId: 231348903 -- 4dcd4e9a6780a81d7a6974c7bf22a037e6482b49 by Abseil Team <absl-team@google.com>: Remove unnecessary register keyword from absl/base/internal/endian.h. PiperOrigin-RevId: 231316570 -- c8584836caa3a10f90a8604a85d4b831310b72ee by Abseil Team <absl-team@google.com>: Fix hashtablez_sampler compilation on older Android NDK builds PiperOrigin-RevId: 231283542 GitOrigin-RevId: 6fdf24a197b964f9bacbebd0ceca305aef1654fc Change-Id: I185b12fb8347e3ad0ffcb2cbb83a53450e5eb938
2019-01-30 19:59:43 +01:00
ABSL_META_INTERNAL_STD_HASH_SFINAE_FRIENDLY_
#define ABSL_HASH_INTERNAL_SUPPORT_LEGACY_HASH_ 1
Export of internal Abseil changes. -- 5f1ab09522226336830d9ea6ef7276d37f536ac5 by Abseil Team <absl-team@google.com>: Clarify the documentation of ABSL_MUST_USE_RESULT. PiperOrigin-RevId: 221663609 -- af4c8359a20d56369fd1dce318220cf3be03ca66 by Greg Falcon <gfalcon@google.com>: Internal change PiperOrigin-RevId: 221538448 -- 487cd09bd1942bf607080deeae38fee6ce66f294 by Eric Fiselier <ericwf@google.com>: Work around emscripten bugs and missing features in absl/time:time_test. The emscripten toolchain has a couple of issues that cause time_test to fail. Specifically: 1) emscripten doesn't support signals. 2) The javascript implementation of strftime/strptime use different expansions of '%c' that mean it doesn't round-trip. PiperOrigin-RevId: 221523701 -- 5823652e6a200b97b07334bc47128dfac40e20fc by Xiaoyi Zhang <zhangxy@google.com>: Fix MSVC compiler warning by explicitly casting to char. Currently our MSVC build breaks with the following error: raw_hash_set.h(406): warning C4309: 'argument': truncation of constant value PiperOrigin-RevId: 221492585 -- c5806358320711a5efbe5c523df13e14ab53a17d by Greg Falcon <gfalcon@google.com>: Replace calls to getpagesize() with the more portable sysconf(_SC_PAGESIZE); the latter is in POSIX 1.0 and is called out in the Linux `getpagesize` man page as a more portable spelling. PiperOrigin-RevId: 221492471 -- 19ffe82851072229bb7ce73f754ffe4c18e8c575 by Abseil Team <absl-team@google.com>: Fix -Wundef error in absl/hash/internal/hash.h. PiperOrigin-RevId: 221444120 -- b30f3d0a848563b6e4ec33f3dc085831dfabb748 by Jon Cohen <cohenjon@google.com>: Import of CCTZ from GitHub. PiperOrigin-RevId: 221339736 GitOrigin-RevId: 5f1ab09522226336830d9ea6ef7276d37f536ac5 Change-Id: I96223d522d98bf6616dea88eb047c2d536eeddd0
2018-11-15 20:55:00 +01:00
#else
#define ABSL_HASH_INTERNAL_SUPPORT_LEGACY_HASH_ 0
#endif
// HashSelect
//
// Type trait to select the appropriate hash implementation to use.
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
2019-03-08 23:06:50 +01:00
// HashSelect::type<T> will give the proper hash implementation, to be invoked
// as:
// HashSelect::type<T>::Invoke(state, value)
// Also, HashSelect::type<T>::value is a boolean equal to `true` if there is a
// valid `Invoke` function. Types that are not hashable will have a ::value of
// `false`.
struct HashSelect {
private:
struct State : HashStateBase<State> {
static State combine_contiguous(State hash_state, const unsigned char*,
size_t);
using State::HashStateBase::combine_contiguous;
};
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
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struct UniquelyRepresentedProbe {
template <typename H, typename T>
static auto Invoke(H state, const T& value)
-> absl::enable_if_t<is_uniquely_represented<T>::value, H> {
return hash_internal::hash_bytes(std::move(state), value);
}
};
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
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struct HashValueProbe {
template <typename H, typename T>
static auto Invoke(H state, const T& value) -> absl::enable_if_t<
std::is_same<H,
decltype(AbslHashValue(std::move(state), value))>::value,
H> {
return AbslHashValue(std::move(state), value);
}
};
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
2019-03-08 23:06:50 +01:00
struct LegacyHashProbe {
#if ABSL_HASH_INTERNAL_SUPPORT_LEGACY_HASH_
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
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template <typename H, typename T>
static auto Invoke(H state, const T& value) -> absl::enable_if_t<
std::is_convertible<
decltype(ABSL_INTERNAL_LEGACY_HASH_NAMESPACE::hash<T>()(value)),
size_t>::value,
H> {
return hash_internal::hash_bytes(
std::move(state),
ABSL_INTERNAL_LEGACY_HASH_NAMESPACE::hash<T>{}(value));
}
#endif // ABSL_HASH_INTERNAL_SUPPORT_LEGACY_HASH_
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
2019-03-08 23:06:50 +01:00
};
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
2019-03-08 23:06:50 +01:00
struct StdHashProbe {
template <typename H, typename T>
static auto Invoke(H state, const T& value)
-> absl::enable_if_t<type_traits_internal::IsHashable<T>::value, H> {
return hash_internal::hash_bytes(std::move(state), std::hash<T>{}(value));
}
};
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
2019-03-08 23:06:50 +01:00
template <typename Hash, typename T>
struct Probe : Hash {
private:
template <typename H, typename = decltype(H::Invoke(
std::declval<State>(), std::declval<const T&>()))>
static std::true_type Test(int);
template <typename U>
static std::false_type Test(char);
public:
static constexpr bool value = decltype(Test<Hash>(0))::value;
};
public:
// Probe each implementation in order.
Export of internal Abseil changes. -- 5a5dba4252e764e6737070bf0a31074bf23a3b41 by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 244898913 -- 3eb7d5b445ffbf08a104e39cd15aecf568417333 by Matt Calabrese <calabrese@google.com>: Introduce absl::is_trivially_move_constructible and absl::is_trivially_move_assignable, and update the absl::is_trivially_copy_constructible and absl::is_trivially_copy_assignable traits to use similar techniques (should now be closer to the standard behavior). PiperOrigin-RevId: 244859015 -- 7da05a24fa786cab3985de0c39a186d73dcbcfb5 by Abseil Team <absl-team@google.com>: Fix misspellings in comments in raw_hash_set.h. PiperOrigin-RevId: 244754700 -- 5c057be96048f21473d5ec45005ab4dcd8dd354f by Derek Mauro <dmauro@google.com>: Internal change PiperOrigin-RevId: 244744239 -- 592394e3c2e98f1238d3fb6fcb0d20c3e3739ba9 by Derek Mauro <dmauro@google.com>: Limit the raw_hash_set prefetch test to x86-64. PiperOrigin-RevId: 244737534 -- 99ebe4e003633c8ff7838b035b31a827994879ef by Derek Mauro <dmauro@google.com>: Workaround warning 4091 in an MSVC header. PiperOrigin-RevId: 244701744 -- 0aa23f09a32efe7985ee55b0217190f08da42477 by Abseil Team <absl-team@google.com>: Fix comment typo. PiperOrigin-RevId: 244659371 -- c6cdb87e9f28062c8daa29b3d8d68182ecc16383 by Derek Mauro <dmauro@google.com>: Fix -Wundef warnings and support -Wundef. PiperOrigin-RevId: 244244968 -- 06b81245f7696b20c3c63b0618d33ac25e29cad6 by Abseil Team <absl-team@google.com>: Fix a typo in inlined_vector.h. PiperOrigin-RevId: 244230809 -- 94877a2125d2cfe837384240e4d6551f39d737e4 by Greg Falcon <gfalcon@google.com>: Fix sysinfo_test for emscripten. PiperOrigin-RevId: 244198804 -- ec7783531ef7f9df2da37d341d61f7cb2bf843f0 by Shaindel Schwartz <shaindel@google.com>: Import of CCTZ from GitHub. Fixes #291. PiperOrigin-RevId: 244184598 -- b652c14fa95ea206c217487ee713b11f5d1762b3 by Matt Calabrese <calabrese@google.com>: Emulate the `in_place_index` and `in_place_type` variable templates such that they are syntactically usable in C++11 with `any` and `variant`. Also pull in the variable templates from namespace std when available. The main observable differences here are: 1) The types of `in_place_index_t<I>` and `in_place_type_t<T>` become function pointer types rather than structs when using the implementation that is not an alias of the std equivalents. 2) The types of `in_place_index<I>` and `in_place_type<T>` are not directly `in_place_index_t<I>` and `in_place_type_t<T>`, but rather they become function types that decay to the corresponding function pointer types. 3) The default constructor for `in_place_index_t` and `in_place_type_t` instantiations is no longer explicit, but for these templates I think that's less important than for something like `in_place_t` since the _type_t and _index_t versions basically never have their template parameter non-deduced when participating in overload resolution with conflicting candidates. 4) While idiomatic usage of `in_place_type_t` and `in_place_index_t` with std::variant and std::any should not be affected, there is the possibility that strange, non-idiomatic uses may be affected in the wild. 5) Default construction (rather than value-initialization) leads to a default-constructed pointer. PiperOrigin-RevId: 244180003 -- b9ac5a96581837ffa24532117b7ea302a5569751 by Derek Mauro <dmauro@google.com>: Fix MSVC debug assertion. isprint is undefined for values not representable as unsigned char or EOF. PiperOrigin-RevId: 244083005 -- 41758be6137c2f25e84b50f23938e49484be2903 by Shaindel Schwartz <shaindel@google.com>: Update config settings for Apple platforms. PiperOrigin-RevId: 244040587 -- c90df6a26db94b0305a0c954455a621542a89d91 by Abseil Team <absl-team@google.com>: Internal change PiperOrigin-RevId: 244024427 -- c71e9ceb89495354eca7d02bd905ffeaa9029aec by Derek Mauro <dmauro@google.com>: Adds missing ABSL_DEFAULT_COPTS and ABSL_TEST_COPTS to CMakeLists.txt Don't error on deprecated declarations in tests. It is completely reasonable to test that code marked deprecated still works. PiperOrigin-RevId: 244003941 -- e1326a96527a8ba9b8d120161545260da9c4562e by Abseil Team <absl-team@google.com>: Internal change. PiperOrigin-RevId: 243990623 -- 90b8e12934c7711e1bfcc0117d21288bf9220dee by Abseil Team <absl-team@google.com>: Add variation of absl::Base64Escape/WebSafeBase64Escape that directly returns its result. PiperOrigin-RevId: 243894308 -- 317fef3344481ebc5c35712d42f5d8a0fa64dff4 by Abseil Team <absl-team@google.com>: Enable raw logging in Emscripten builds. PiperOrigin-RevId: 243893705 GitOrigin-RevId: 5a5dba4252e764e6737070bf0a31074bf23a3b41 Change-Id: I19293aab73cc98d9e9bf6a9fdc30819764adb9db
2019-04-23 21:04:13 +02:00
// disjunction provides short circuiting wrt instantiation.
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
2019-03-08 23:06:50 +01:00
template <typename T>
using Apply = absl::disjunction< //
Probe<UniquelyRepresentedProbe, T>, //
Probe<HashValueProbe, T>, //
Probe<LegacyHashProbe, T>, //
Probe<StdHashProbe, T>, //
std::false_type>;
};
template <typename T>
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
2019-03-08 23:06:50 +01:00
struct is_hashable
: std::integral_constant<bool, HashSelect::template Apply<T>::value> {};
// CityHashState
class CityHashState : public HashStateBase<CityHashState> {
// absl::uint128 is not an alias or a thin wrapper around the intrinsic.
// We use the intrinsic when available to improve performance.
#ifdef ABSL_HAVE_INTRINSIC_INT128
using uint128 = __uint128_t;
#else // ABSL_HAVE_INTRINSIC_INT128
using uint128 = absl::uint128;
#endif // ABSL_HAVE_INTRINSIC_INT128
static constexpr uint64_t kMul =
sizeof(size_t) == 4 ? uint64_t{0xcc9e2d51}
: uint64_t{0x9ddfea08eb382d69};
template <typename T>
using IntegralFastPath =
conjunction<std::is_integral<T>, is_uniquely_represented<T>>;
public:
// Move only
CityHashState(CityHashState&&) = default;
CityHashState& operator=(CityHashState&&) = default;
// CityHashState::combine_contiguous()
//
// Fundamental base case for hash recursion: mixes the given range of bytes
// into the hash state.
static CityHashState combine_contiguous(CityHashState hash_state,
const unsigned char* first,
size_t size) {
return CityHashState(
CombineContiguousImpl(hash_state.state_, first, size,
std::integral_constant<int, sizeof(size_t)>{}));
}
using CityHashState::HashStateBase::combine_contiguous;
// CityHashState::hash()
//
// For performance reasons in non-opt mode, we specialize this for
// integral types.
// Otherwise we would be instantiating and calling dozens of functions for
// something that is just one multiplication and a couple xor's.
// The result should be the same as running the whole algorithm, but faster.
template <typename T, absl::enable_if_t<IntegralFastPath<T>::value, int> = 0>
static size_t hash(T value) {
return static_cast<size_t>(Mix(Seed(), static_cast<uint64_t>(value)));
}
// Overload of CityHashState::hash()
template <typename T, absl::enable_if_t<!IntegralFastPath<T>::value, int> = 0>
static size_t hash(const T& value) {
return static_cast<size_t>(combine(CityHashState{}, value).state_);
}
private:
// Invoked only once for a given argument; that plus the fact that this is
// move-only ensures that there is only one non-moved-from object.
CityHashState() : state_(Seed()) {}
// Workaround for MSVC bug.
// We make the type copyable to fix the calling convention, even though we
// never actually copy it. Keep it private to not affect the public API of the
// type.
CityHashState(const CityHashState&) = default;
explicit CityHashState(uint64_t state) : state_(state) {}
// Implementation of the base case for combine_contiguous where we actually
// mix the bytes into the state.
// Dispatch to different implementations of the combine_contiguous depending
// on the value of `sizeof(size_t)`.
static uint64_t CombineContiguousImpl(uint64_t state,
const unsigned char* first, size_t len,
std::integral_constant<int, 4>
/* sizeof_size_t */);
static uint64_t CombineContiguousImpl(uint64_t state,
const unsigned char* first, size_t len,
std::integral_constant<int, 8>
/* sizeof_size_t*/);
Export of internal Abseil changes -- 074a799119ac881b8b8ce59ef7a3166d1aa025ac by Tom Manshreck <shreck@google.com>: nit: Add return info for StrCat PiperOrigin-RevId: 278647298 -- d58a2a39ab6f50266cc695506ba2e86bdb45d795 by Mark Barolak <mbar@google.com>: Stop suppressing no-nested-anon-types warnings because there aren't actually any warnings to suppress. PiperOrigin-RevId: 278440548 -- 445051bd280b9a6f608a8c80b3d7cafcc1377a03 by Abseil Team <absl-team@google.com>: ResetThreadIdentity does not need to clear identity->waiter_state. ResetThreadIdentity is only called by NewThreadIdentity. NewThreadIdentity is only called by CreateThreadIdentity. CreateThreadIdentity calls PerThreadSem::Init, which initializes identity->waiter_state, immediately after calling NewThreadIdentity. Therefore ResetThreadIdentity does not need to clear identity->waiter_state. PiperOrigin-RevId: 278429844 -- c2079b664d92be40d5e365abcca4e9b3505a75a6 by Abseil Team <absl-team@google.com>: Delete the f->header.magic check in LowLevelAlloc::Free(). The f->header.magic check in LowLevelAlloc::Free() is redundant, because AddToFreeList() will immediately perform the same check. Also fix a typo in the comment that documents the lock requirements for Next(). The comment should say "L >= arena->mu", which is equivalent to EXCLUSIVE_LOCKS_REQUIRED(arena->mu). NOTE: LowLevelAlloc::Free() performs the f->header.magic check without holding the arena lock. This may have caused the TSAN data race warning reported in bug 143697235. PiperOrigin-RevId: 278414140 -- 5534f35ce677165700117d868f51607ed1f0d73b by Greg Falcon <gfalcon@google.com>: Add an internal (unsupported) PiecewiseCombiner class to allow hashing buffers piecewise. PiperOrigin-RevId: 278388902 GitOrigin-RevId: 074a799119ac881b8b8ce59ef7a3166d1aa025ac Change-Id: I61734850cbbb01c7585e8c736a5bb56e416512a8
2019-11-05 18:49:15 +01:00
// Slow dispatch path for calls to CombineContiguousImpl with a size argument
// larger than PiecewiseChunkSize(). Has the same effect as calling
// CombineContiguousImpl() repeatedly with the chunk stride size.
static uint64_t CombineLargeContiguousImpl32(uint64_t state,
const unsigned char* first,
size_t len);
static uint64_t CombineLargeContiguousImpl64(uint64_t state,
const unsigned char* first,
size_t len);
// Reads 9 to 16 bytes from p.
// The first 8 bytes are in .first, the rest (zero padded) bytes are in
// .second.
static std::pair<uint64_t, uint64_t> Read9To16(const unsigned char* p,
size_t len) {
uint64_t high = little_endian::Load64(p + len - 8);
return {little_endian::Load64(p), high >> (128 - len * 8)};
}
// Reads 4 to 8 bytes from p. Zero pads to fill uint64_t.
static uint64_t Read4To8(const unsigned char* p, size_t len) {
return (static_cast<uint64_t>(little_endian::Load32(p + len - 4))
<< (len - 4) * 8) |
little_endian::Load32(p);
}
// Reads 1 to 3 bytes from p. Zero pads to fill uint32_t.
static uint32_t Read1To3(const unsigned char* p, size_t len) {
return static_cast<uint32_t>((p[0]) | //
(p[len / 2] << (len / 2 * 8)) | //
(p[len - 1] << ((len - 1) * 8)));
}
ABSL_ATTRIBUTE_ALWAYS_INLINE static uint64_t Mix(uint64_t state, uint64_t v) {
using MultType =
absl::conditional_t<sizeof(size_t) == 4, uint64_t, uint128>;
// We do the addition in 64-bit space to make sure the 128-bit
// multiplication is fast. If we were to do it as MultType the compiler has
// to assume that the high word is non-zero and needs to perform 2
// multiplications instead of one.
MultType m = state + v;
m *= kMul;
return static_cast<uint64_t>(m ^ (m >> (sizeof(m) * 8 / 2)));
}
// Seed()
//
// A non-deterministic seed.
//
// The current purpose of this seed is to generate non-deterministic results
// and prevent having users depend on the particular hash values.
// It is not meant as a security feature right now, but it leaves the door
// open to upgrade it to a true per-process random seed. A true random seed
// costs more and we don't need to pay for that right now.
//
// On platforms with ASLR, we take advantage of it to make a per-process
// random value.
// See https://en.wikipedia.org/wiki/Address_space_layout_randomization
//
// On other platforms this is still going to be non-deterministic but most
// probably per-build and not per-process.
ABSL_ATTRIBUTE_ALWAYS_INLINE static uint64_t Seed() {
return static_cast<uint64_t>(reinterpret_cast<uintptr_t>(kSeed));
}
static const void* const kSeed;
uint64_t state_;
};
// CityHashState::CombineContiguousImpl()
inline uint64_t CityHashState::CombineContiguousImpl(
uint64_t state, const unsigned char* first, size_t len,
std::integral_constant<int, 4> /* sizeof_size_t */) {
// For large values we use CityHash, for small ones we just use a
// multiplicative hash.
uint64_t v;
if (len > 8) {
Export of internal Abseil changes -- 074a799119ac881b8b8ce59ef7a3166d1aa025ac by Tom Manshreck <shreck@google.com>: nit: Add return info for StrCat PiperOrigin-RevId: 278647298 -- d58a2a39ab6f50266cc695506ba2e86bdb45d795 by Mark Barolak <mbar@google.com>: Stop suppressing no-nested-anon-types warnings because there aren't actually any warnings to suppress. PiperOrigin-RevId: 278440548 -- 445051bd280b9a6f608a8c80b3d7cafcc1377a03 by Abseil Team <absl-team@google.com>: ResetThreadIdentity does not need to clear identity->waiter_state. ResetThreadIdentity is only called by NewThreadIdentity. NewThreadIdentity is only called by CreateThreadIdentity. CreateThreadIdentity calls PerThreadSem::Init, which initializes identity->waiter_state, immediately after calling NewThreadIdentity. Therefore ResetThreadIdentity does not need to clear identity->waiter_state. PiperOrigin-RevId: 278429844 -- c2079b664d92be40d5e365abcca4e9b3505a75a6 by Abseil Team <absl-team@google.com>: Delete the f->header.magic check in LowLevelAlloc::Free(). The f->header.magic check in LowLevelAlloc::Free() is redundant, because AddToFreeList() will immediately perform the same check. Also fix a typo in the comment that documents the lock requirements for Next(). The comment should say "L >= arena->mu", which is equivalent to EXCLUSIVE_LOCKS_REQUIRED(arena->mu). NOTE: LowLevelAlloc::Free() performs the f->header.magic check without holding the arena lock. This may have caused the TSAN data race warning reported in bug 143697235. PiperOrigin-RevId: 278414140 -- 5534f35ce677165700117d868f51607ed1f0d73b by Greg Falcon <gfalcon@google.com>: Add an internal (unsupported) PiecewiseCombiner class to allow hashing buffers piecewise. PiperOrigin-RevId: 278388902 GitOrigin-RevId: 074a799119ac881b8b8ce59ef7a3166d1aa025ac Change-Id: I61734850cbbb01c7585e8c736a5bb56e416512a8
2019-11-05 18:49:15 +01:00
if (ABSL_PREDICT_FALSE(len > PiecewiseChunkSize())) {
return CombineLargeContiguousImpl32(state, first, len);
}
v = absl::hash_internal::CityHash32(reinterpret_cast<const char*>(first), len);
} else if (len >= 4) {
v = Read4To8(first, len);
} else if (len > 0) {
v = Read1To3(first, len);
} else {
// Empty ranges have no effect.
return state;
}
return Mix(state, v);
}
// Overload of CityHashState::CombineContiguousImpl()
inline uint64_t CityHashState::CombineContiguousImpl(
uint64_t state, const unsigned char* first, size_t len,
std::integral_constant<int, 8> /* sizeof_size_t */) {
// For large values we use CityHash, for small ones we just use a
// multiplicative hash.
uint64_t v;
if (len > 16) {
Export of internal Abseil changes -- 074a799119ac881b8b8ce59ef7a3166d1aa025ac by Tom Manshreck <shreck@google.com>: nit: Add return info for StrCat PiperOrigin-RevId: 278647298 -- d58a2a39ab6f50266cc695506ba2e86bdb45d795 by Mark Barolak <mbar@google.com>: Stop suppressing no-nested-anon-types warnings because there aren't actually any warnings to suppress. PiperOrigin-RevId: 278440548 -- 445051bd280b9a6f608a8c80b3d7cafcc1377a03 by Abseil Team <absl-team@google.com>: ResetThreadIdentity does not need to clear identity->waiter_state. ResetThreadIdentity is only called by NewThreadIdentity. NewThreadIdentity is only called by CreateThreadIdentity. CreateThreadIdentity calls PerThreadSem::Init, which initializes identity->waiter_state, immediately after calling NewThreadIdentity. Therefore ResetThreadIdentity does not need to clear identity->waiter_state. PiperOrigin-RevId: 278429844 -- c2079b664d92be40d5e365abcca4e9b3505a75a6 by Abseil Team <absl-team@google.com>: Delete the f->header.magic check in LowLevelAlloc::Free(). The f->header.magic check in LowLevelAlloc::Free() is redundant, because AddToFreeList() will immediately perform the same check. Also fix a typo in the comment that documents the lock requirements for Next(). The comment should say "L >= arena->mu", which is equivalent to EXCLUSIVE_LOCKS_REQUIRED(arena->mu). NOTE: LowLevelAlloc::Free() performs the f->header.magic check without holding the arena lock. This may have caused the TSAN data race warning reported in bug 143697235. PiperOrigin-RevId: 278414140 -- 5534f35ce677165700117d868f51607ed1f0d73b by Greg Falcon <gfalcon@google.com>: Add an internal (unsupported) PiecewiseCombiner class to allow hashing buffers piecewise. PiperOrigin-RevId: 278388902 GitOrigin-RevId: 074a799119ac881b8b8ce59ef7a3166d1aa025ac Change-Id: I61734850cbbb01c7585e8c736a5bb56e416512a8
2019-11-05 18:49:15 +01:00
if (ABSL_PREDICT_FALSE(len > PiecewiseChunkSize())) {
return CombineLargeContiguousImpl64(state, first, len);
}
v = absl::hash_internal::CityHash64(reinterpret_cast<const char*>(first), len);
} else if (len > 8) {
auto p = Read9To16(first, len);
state = Mix(state, p.first);
v = p.second;
} else if (len >= 4) {
v = Read4To8(first, len);
} else if (len > 0) {
v = Read1To3(first, len);
} else {
// Empty ranges have no effect.
return state;
}
return Mix(state, v);
}
struct AggregateBarrier {};
// HashImpl
// Add a private base class to make sure this type is not an aggregate.
// Aggregates can be aggregate initialized even if the default constructor is
// deleted.
struct PoisonedHash : private AggregateBarrier {
PoisonedHash() = delete;
PoisonedHash(const PoisonedHash&) = delete;
PoisonedHash& operator=(const PoisonedHash&) = delete;
};
template <typename T>
struct HashImpl {
size_t operator()(const T& value) const { return CityHashState::hash(value); }
};
template <typename T>
struct Hash
: absl::conditional_t<is_hashable<T>::value, HashImpl<T>, PoisonedHash> {};
template <typename H>
template <typename T, typename... Ts>
H HashStateBase<H>::combine(H state, const T& value, const Ts&... values) {
Export of internal Abseil changes. -- 5dc8d7504b7c11710b19365a6582c288c8992366 by Derek Mauro <dmauro@google.com>: Fix constexpr Span::last under MSVC and add Span constexpr tests. PiperOrigin-RevId: 237515952 -- 5ea8c146e653bbc49ff7e698699478242df7de35 by Derek Mauro <dmauro@google.com>: Implement Span::first and Span::last from C++20. https://github.com/abseil/abseil-cpp/pull/274 PiperOrigin-RevId: 237494399 -- 08db3417f1d8fe4556255d57a2f0df51b09bdd9a by Derek Mauro <dmauro@google.com>: HTTPS in more URLs. PiperOrigin-RevId: 237486823 -- 83ec63a7f8e47b62af619546f9f7b3bf72e74e86 by Derek Mauro <dmauro@google.com>: Changed HTTP URLs to HTTPS where possible. https://github.com/abseil/abseil-cpp/pull/270 PiperOrigin-RevId: 237445310 -- 220bf279c14cb31efa239500d1a70e0ac0c32e3c by Abseil Team <absl-team@google.com>: Support parsing decltype(nullptr) as a type. PiperOrigin-RevId: 237336739 -- ced234bbe78f5d495c3f6f6a9c2e0a95f7c080a5 by Gennadiy Rozental <rogeeff@google.com>: Introduce internal interface for setting environment variable value in scope PiperOrigin-RevId: 237275806 -- 1f1acb4e294af24d9f7598e85163d5e1d9958ae9 by Samuel Benzaquen <sbenza@google.com>: Avoid using aliases in the SFINAE expressions to make it more compatible with MSVC. Turn on the tests in MSVC. PiperOrigin-RevId: 237261456 -- 06cf7de6250a0572ef90fa1176f742ca0451ce71 by Derek Mauro <dmauro@google.com>: Fix unused variable warning. PiperOrigin-RevId: 237108006 GitOrigin-RevId: 5dc8d7504b7c11710b19365a6582c288c8992366 Change-Id: Ife5182c80942945c4e8700844c8febb482d6ad82
2019-03-08 23:06:50 +01:00
return H::combine(hash_internal::HashSelect::template Apply<T>::Invoke(
std::move(state), value),
values...);
}
// HashStateBase::combine_contiguous()
template <typename H>
template <typename T>
H HashStateBase<H>::combine_contiguous(H state, const T* data, size_t size) {
return hash_internal::hash_range_or_bytes(std::move(state), data, size);
}
Export of internal Abseil changes -- 074a799119ac881b8b8ce59ef7a3166d1aa025ac by Tom Manshreck <shreck@google.com>: nit: Add return info for StrCat PiperOrigin-RevId: 278647298 -- d58a2a39ab6f50266cc695506ba2e86bdb45d795 by Mark Barolak <mbar@google.com>: Stop suppressing no-nested-anon-types warnings because there aren't actually any warnings to suppress. PiperOrigin-RevId: 278440548 -- 445051bd280b9a6f608a8c80b3d7cafcc1377a03 by Abseil Team <absl-team@google.com>: ResetThreadIdentity does not need to clear identity->waiter_state. ResetThreadIdentity is only called by NewThreadIdentity. NewThreadIdentity is only called by CreateThreadIdentity. CreateThreadIdentity calls PerThreadSem::Init, which initializes identity->waiter_state, immediately after calling NewThreadIdentity. Therefore ResetThreadIdentity does not need to clear identity->waiter_state. PiperOrigin-RevId: 278429844 -- c2079b664d92be40d5e365abcca4e9b3505a75a6 by Abseil Team <absl-team@google.com>: Delete the f->header.magic check in LowLevelAlloc::Free(). The f->header.magic check in LowLevelAlloc::Free() is redundant, because AddToFreeList() will immediately perform the same check. Also fix a typo in the comment that documents the lock requirements for Next(). The comment should say "L >= arena->mu", which is equivalent to EXCLUSIVE_LOCKS_REQUIRED(arena->mu). NOTE: LowLevelAlloc::Free() performs the f->header.magic check without holding the arena lock. This may have caused the TSAN data race warning reported in bug 143697235. PiperOrigin-RevId: 278414140 -- 5534f35ce677165700117d868f51607ed1f0d73b by Greg Falcon <gfalcon@google.com>: Add an internal (unsupported) PiecewiseCombiner class to allow hashing buffers piecewise. PiperOrigin-RevId: 278388902 GitOrigin-RevId: 074a799119ac881b8b8ce59ef7a3166d1aa025ac Change-Id: I61734850cbbb01c7585e8c736a5bb56e416512a8
2019-11-05 18:49:15 +01:00
// HashStateBase::PiecewiseCombiner::add_buffer()
template <typename H>
H PiecewiseCombiner::add_buffer(H state, const unsigned char* data,
size_t size) {
if (position_ + size < PiecewiseChunkSize()) {
// This partial chunk does not fill our existing buffer
memcpy(buf_ + position_, data, size);
position_ += size;
return std::move(state);
}
// Complete the buffer and hash it
const size_t bytes_needed = PiecewiseChunkSize() - position_;
memcpy(buf_ + position_, data, bytes_needed);
state = H::combine_contiguous(std::move(state), buf_, PiecewiseChunkSize());
data += bytes_needed;
size -= bytes_needed;
// Hash whatever chunks we can without copying
while (size >= PiecewiseChunkSize()) {
state = H::combine_contiguous(std::move(state), data, PiecewiseChunkSize());
data += PiecewiseChunkSize();
size -= PiecewiseChunkSize();
}
// Fill the buffer with the remainder
memcpy(buf_, data, size);
position_ = size;
return std::move(state);
}
// HashStateBase::PiecewiseCombiner::finalize()
template <typename H>
H PiecewiseCombiner::finalize(H state) {
// Hash the remainder left in the buffer, which may be empty
return H::combine_contiguous(std::move(state), buf_, position_);
}
} // namespace hash_internal
Export of internal Abseil changes -- c99f979ad34f155fbeeea69b88bdc7458d89a21c by Derek Mauro <dmauro@google.com>: Remove a floating point division by zero test. This isn't testing behavior related to the library, and MSVC warns about it in opt mode. PiperOrigin-RevId: 285220804 -- 68b015491f0dbf1ab547994673281abd1f34cd4b by Gennadiy Rozental <rogeeff@google.com>: This CL introduces following changes to the class FlagImpl: * We eliminate the CommandLineFlagLocks struct. Instead callback guard and callback function are combined into a single CallbackData struct, while primary data lock is stored separately. * CallbackData member of class FlagImpl is initially set to be nullptr and is only allocated and initialized when a flag's callback is being set. For most flags we do not pay for the extra space and extra absl::Mutex now. * Primary data guard is stored in data_guard_ data member. This is a properly aligned character buffer of necessary size. During initialization of the flag we construct absl::Mutex in this space using placement new call. * We now avoid extra value copy after successful attempt to parse value out of string. Instead we swap flag's current value with tentative value we just produced. PiperOrigin-RevId: 285132636 -- ed45d118fb818969eb13094cf7827c885dfc562c by Tom Manshreck <shreck@google.com>: Change null-term* (and nul-term*) to NUL-term* in comments PiperOrigin-RevId: 285036610 -- 729619017944db895ce8d6d29c1995aa2e5628a5 by Derek Mauro <dmauro@google.com>: Use the Posix implementation of thread identity on MinGW. Some versions of MinGW suffer from thread_local bugs. PiperOrigin-RevId: 285022920 -- 39a25493503c76885bc3254c28f66a251c5b5bb0 by Greg Falcon <gfalcon@google.com>: Implementation detail change. Add further ABSL_NAMESPACE_BEGIN and _END annotation macros to files in Abseil. PiperOrigin-RevId: 285012012 GitOrigin-RevId: c99f979ad34f155fbeeea69b88bdc7458d89a21c Change-Id: I4c85d3704e45d11a9ac50d562f39640a6adbedc1
2019-12-12 19:36:03 +01:00
ABSL_NAMESPACE_END
} // namespace absl
#endif // ABSL_HASH_INTERNAL_HASH_H_