Export of internal Abseil changes
-- 2c5c118f0615ba90e48ee2f18eccc9f511740f6d by Samuel Benzaquen <sbenza@google.com>: Rename internal macros to follow the convention in absl. PiperOrigin-RevId: 299906738 -- 92d84a707c7ebc4ec19bdd92d5765d1b6d218c1e by Derek Mauro <dmauro@google.com>: Import GitHub #629: Skip the .exe suffix in the helpshort filter on Windows PiperOrigin-RevId: 299892396 -- 2a6910d4be6c67a8376628764121b528ff53504d by Abseil Team <absl-team@google.com>: Use unsigned int128 intrinsic when available. It generates better branchless code. PiperOrigin-RevId: 299848585 -- 110c16cf0a739e1df5028fb6fbd03ef5dde1d278 by Derek Mauro <dmauro@google.com>: Import GitHub #594: Avoid reading the registry for Windows UWP apps PiperOrigin-RevId: 299821671 -- d8397d367e88163e5e8a47f379c716352dc91d03 by Greg Falcon <gfalcon@google.com>: Add absl::Hash support for Cord. The hash function is heterogeneous with other string types: a Cord and a string with the same byte sequence will hash to the same value. SwissTable types know about Cord, and will allow heterogeneous lookup (e.g., you can pass a Cord to flat_hash_map<string, T>::find(), and vice versa.) Add a missing dependency to the cmake Cord target. PiperOrigin-RevId: 299443713 GitOrigin-RevId: 2c5c118f0615ba90e48ee2f18eccc9f511740f6d Change-Id: I7b087c7984b0cb52c4b337d49266c467b98ebdf9
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21 changed files with 274 additions and 51 deletions
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@ -43,6 +43,7 @@
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#include "absl/container/fixed_array.h"
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#include "absl/meta/type_traits.h"
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#include "absl/numeric/int128.h"
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#include "absl/strings/cord.h"
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#include "absl/strings/string_view.h"
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#include "absl/types/optional.h"
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#include "absl/types/variant.h"
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@ -413,6 +414,7 @@ H AbslHashValue(H hash_state, const std::shared_ptr<T>& ptr) {
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// All the string-like types supported here provide the same hash expansion for
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// the same character sequence. These types are:
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//
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// - `absl::Cord`
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// - `std::string` (and std::basic_string<char, std::char_traits<char>, A> for
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// any allocator A)
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// - `absl::string_view` and `std::string_view`
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@ -441,6 +443,25 @@ H AbslHashValue(
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str.size());
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}
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template <typename H>
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H HashFragmentedCord(H hash_state, const absl::Cord& c) {
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PiecewiseCombiner combiner;
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c.ForEachChunk([&combiner, &hash_state](absl::string_view chunk) {
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hash_state =
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combiner.add_buffer(std::move(hash_state), chunk.data(), chunk.size());
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});
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return H::combine(combiner.finalize(std::move(hash_state)), c.size());
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}
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template <typename H>
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H AbslHashValue(H hash_state, const absl::Cord& c) {
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absl::optional<absl::string_view> maybe_flat = c.TryFlat();
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if (maybe_flat.has_value()) {
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return H::combine(std::move(hash_state), *maybe_flat);
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}
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return hash_internal::HashFragmentedCord(std::move(hash_state), c);
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}
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// -----------------------------------------------------------------------------
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// AbslHashValue for Sequence Containers
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// -----------------------------------------------------------------------------
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