mirror of https://gitee.com/bigwinds/arangodb
118 lines
3.7 KiB
C++
118 lines
3.7 KiB
C++
////////////////////////////////////////////////////////////////////////////////
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/// DISCLAIMER
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///
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/// Copyright 2016 by EMC Corporation, All Rights Reserved
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///
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/// Licensed under the Apache License, Version 2.0 (the "License");
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/// you may not use this file except in compliance with the License.
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/// You may obtain a copy of the License at
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///
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/// http://www.apache.org/licenses/LICENSE-2.0
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///
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/// Unless required by applicable law or agreed to in writing, software
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/// distributed under the License is distributed on an "AS IS" BASIS,
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/// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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/// See the License for the specific language governing permissions and
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/// limitations under the License.
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///
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/// Copyright holder is EMC Corporation
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///
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/// @author Andrey Abramov
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/// @author Vasiliy Nabatchikov
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////////////////////////////////////////////////////////////////////////////////
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#ifndef IRESEARCH_HASH_UTILS_H
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#define IRESEARCH_HASH_UTILS_H
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#include "shared.hpp"
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#include "string.hpp"
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// -----------------------------------------------------------------------------
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// --SECTION-- hash utils
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// -----------------------------------------------------------------------------
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NS_ROOT
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FORCE_INLINE size_t hash_combine(size_t seed, size_t v) NOEXCEPT {
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return seed ^ (v + 0x9e3779b9 + (seed<<6) + (seed>>2));
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}
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template<typename T>
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FORCE_INLINE size_t hash_combine(size_t seed, T const& v) {
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return hash_combine(seed, std::hash<T>()(v));
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}
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template<typename Elem>
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class IRESEARCH_API_TEMPLATE hashed_basic_string_ref : public basic_string_ref<Elem> {
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public:
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typedef basic_string_ref<Elem> base_t;
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hashed_basic_string_ref(size_t hash, const base_t& ref)
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: base_t(ref), hash_(hash) {
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}
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hashed_basic_string_ref(size_t hash, const base_t& ref, size_t size)
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: base_t(ref, size), hash_(hash) {
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}
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hashed_basic_string_ref(size_t hash, const typename base_t::char_type* ptr)
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: base_t(ptr), hash_(hash) {
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}
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hashed_basic_string_ref(size_t hash, const typename base_t::char_type* ptr, size_t size)
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: base_t(ptr, size), hash_(hash) {
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}
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hashed_basic_string_ref(size_t hash, const std::basic_string<typename base_t::char_type>& str)
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: base_t(str), hash_(hash) {
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}
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hashed_basic_string_ref(size_t hash, const std::basic_string<typename base_t::char_type>& str, size_t size)
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: base_t(str, size), hash_(hash) {
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}
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inline size_t hash() const { return hash_; }
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private:
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size_t hash_;
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}; // hashed_basic_string_ref
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template<typename Elem, typename Hasher>
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hashed_basic_string_ref<Elem> make_hashed_ref(const basic_string_ref<Elem>& ref, const Hasher& hasher = Hasher()) {
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return hashed_basic_string_ref<Elem>(hasher(ref), ref);
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}
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template<typename Elem, typename Hasher>
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hashed_basic_string_ref<Elem> make_hashed_ref(const basic_string_ref<Elem>& ref, size_t size, const Hasher& hasher = Hasher()) {
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return hashed_basic_string_ref<Elem>(hasher(ref), ref, size);
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}
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typedef hashed_basic_string_ref<byte_type> hashed_bytes_ref;
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typedef hashed_basic_string_ref<char> hashed_string_ref;
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NS_END
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// -----------------------------------------------------------------------------
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// --SECTION-- std extensions
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// -----------------------------------------------------------------------------
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NS_BEGIN(std)
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template<>
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struct hash<::iresearch::hashed_bytes_ref> {
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size_t operator()(const ::iresearch::hashed_bytes_ref& value) const {
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return value.hash();
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}
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};
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template<>
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struct hash<::iresearch::hashed_string_ref> {
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size_t operator()(const ::iresearch::hashed_string_ref& value) const {
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return value.hash();
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}
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};
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NS_END // std
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#endif
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