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author | Abseil Team <absl-team@google.com> | 2020-03-09T19·34-0700 |
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committer | Derek Mauro <dmauro@google.com> | 2020-03-09T20·10-0400 |
commit | d936052d32a5b7ca08b0199a6724724aea432309 (patch) | |
tree | f14866c5460c73ba3ba3812941a0426ad51496cd /absl/hash/internal | |
parent | 238b9a59c874f8271ce781d9d05d81eb61728132 (diff) |
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
Diffstat (limited to 'absl/hash/internal')
-rw-r--r-- | absl/hash/internal/hash.h | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/absl/hash/internal/hash.h b/absl/hash/internal/hash.h index 1cc2c5e5ae48..025d287f39c9 100644 --- a/absl/hash/internal/hash.h +++ b/absl/hash/internal/hash.h @@ -43,6 +43,7 @@ #include "absl/container/fixed_array.h" #include "absl/meta/type_traits.h" #include "absl/numeric/int128.h" +#include "absl/strings/cord.h" #include "absl/strings/string_view.h" #include "absl/types/optional.h" #include "absl/types/variant.h" @@ -413,6 +414,7 @@ H AbslHashValue(H hash_state, const std::shared_ptr<T>& ptr) { // All the string-like types supported here provide the same hash expansion for // the same character sequence. These types are: // +// - `absl::Cord` // - `std::string` (and std::basic_string<char, std::char_traits<char>, A> for // any allocator A) // - `absl::string_view` and `std::string_view` @@ -441,6 +443,25 @@ H AbslHashValue( str.size()); } +template <typename H> +H HashFragmentedCord(H hash_state, const absl::Cord& c) { + PiecewiseCombiner combiner; + c.ForEachChunk([&combiner, &hash_state](absl::string_view chunk) { + hash_state = + combiner.add_buffer(std::move(hash_state), chunk.data(), chunk.size()); + }); + return H::combine(combiner.finalize(std::move(hash_state)), c.size()); +} + +template <typename H> +H AbslHashValue(H hash_state, const absl::Cord& c) { + absl::optional<absl::string_view> maybe_flat = c.TryFlat(); + if (maybe_flat.has_value()) { + return H::combine(std::move(hash_state), *maybe_flat); + } + return hash_internal::HashFragmentedCord(std::move(hash_state), c); +} + // ----------------------------------------------------------------------------- // AbslHashValue for Sequence Containers // ----------------------------------------------------------------------------- |