Hopscotch Hashing [Ready]

cds/container/details/hopscotch_hashmap_base.h

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+/*
+    This file is a part of libcds - Concurrent Data Structures library
+
+    (C) Copyright Maxim Khizhinsky ([email protected]) 2006-2017
+
+    Source code repo: http://github.com/khizmax/libcds/
+    Download: http://sourceforge.net/projects/libcds/files/
+
+    Redistribution and use in source and binary forms, with or without
+    modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright notice, this
+      list of conditions and the following disclaimer.
+
+    * Redistributions in binary form must reproduce the above copyright notice,
+      this list of conditions and the following disclaimer in the documentation
+      and/or other materials provided with the distribution.
+
+    THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
+    AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
+    IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+    DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
+    FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+    DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
+    SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+    CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
+    OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+    OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+#ifndef CDSLIB_CONTAINER_DETAILS_HOPSCOTCH_HASHMAP_BASE_H
+#define CDSLIB_CONTAINER_DETAILS_HOPSCOTCH_HASHMAP_BASE_H
+
+#include <cds/intrusive/hopscotch_hashset.h>
+
+namespace cds { namespace container {
+
+    /// Hopscotch hashmap related definitions
+    /** @ingroup cds_nonintrusive_helper
+    */
+    namespace hopscotch_hashmap_ns {
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Lock striping concurrent access policy. This is typedef for intrusive::hopscotch_hashset::striping template
+        class striping
+        {};
+#else
+        using intrusive::hopscotch_hashset::striping;
+#endif
+
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Refinable concurrent access policy. This is typedef for intrusive::hopscotch_hashset::refinable template
+        class refinable
+        {};
+#else
+        using intrusive::hopscotch_hashset::refinable;
+#endif
+
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Striping internal statistics. This is typedef for intrusive::hopscotch_hashset::striping_stat
+        class striping_stat
+        {};
+#else
+        using intrusive::hopscotch_hashset::striping_stat;
+#endif
+
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Empty striping internal statistics. This is typedef for intrusive::hopscotch_hashset::empty_striping_stat
+        class empty_striping_stat
+        {};
+#else
+        using intrusive::hopscotch_hashset::empty_striping_stat;
+#endif
+
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Refinable internal statistics. This is typedef for intrusive::hopscotch_hashset::refinable_stat
+        class refinable_stat
+        {};
+#else
+        using intrusive::hopscotch_hashset::refinable_stat;
+#endif
+
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Empty refinable internal statistics. This is typedef for intrusive::hopscotch_hashset::empty_refinable_stat
+        class empty_refinable_stat
+        {};
+#else
+        using intrusive::hopscotch_hashset::empty_refinable_stat;
+#endif
+
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Hopscotch hashmap statistics. This is typedef for intrusive::hopscotch_hashset::stat
+        class stat
+        {};
+#else
+        using intrusive::hopscotch_hashset::stat;
+#endif
+
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Hopscotch hashmap empty statistics.This is typedef for intrusive::hopscotch_hashset::empty_stat
+        class empty_stat
+        {};
+#else
+        using intrusive::hopscotch_hashset::empty_stat;
+#endif
+
+        /// Option specifying whether to store hash values in the node
+        /**
+             This option reserves additional space in the hook to store the hash value of the object once it's introduced in the container.
+             When this option is used, the unordered container will store the calculated hash value in the hook and rehashing operations won't need
+             to recalculate the hash of the value. This option will improve the performance of unordered containers
+             when rehashing is frequent or hashing the value is a slow operation
+
+             The \p Enable template parameter toggles the feature:
+             - the value \p true enables storing the hash values
+             - the value \p false disables storing the hash values
+        */
+        template <bool Enable>
+        struct store_hash
+        {
+            //@cond
+            template <typename Base>
+            struct pack: public Base {
+                static bool const store_hash = Enable;
+            };
+            //@endcond
+        };
+
+#ifdef CDS_DOXYGEN_INVOKED
+        /// Probe set type option
+        /**
+            @copydetails cds::intrusive::hopscotch_hashset::probeset_type
+        */
+        template <typename Type>
+        struct probeset_type
+        {};
+#else
+        using intrusive::hopscotch_hashset::probeset_type;
+#endif
+
+        using intrusive::hopscotch_hashset::list;
+        using intrusive::hopscotch_hashset::vector;
+
+        /// Type traits for hopscotch hashmap class
+        struct traits
+        {
+            /// Hash functors tuple
+            /**
+                This is mandatory type and has no predefined one.
+
+                At least, two hash functors should be provided. All hash functor
+                should be orthogonal (different): for each <tt> i,j: i != j => h[i](x) != h[j](x) </tt>.
+                The hash functors are defined as <tt> std::tuple< H1, H2, ... Hn > </tt>:
+                \@code cds::opt::hash< std::tuple< h1, h2 > > \@endcode
+                The number of hash functors specifies the number \p k - the count of hash tables in hopscotch hashing.
+
+                To specify hash tuple in traits you should use \p cds::opt::hash_tuple:
+                \code
+                struct my_traits: public cds::container::hopscotch_hashmap::traits {
+                    typedef cds::opt::hash_tuple< hash1, hash2 > hash;
+                };
+                \endcode
+            */
+            typedef cds::opt::none      hash;
+
+            /// Concurrent access policy
+            /**
+                Available opt::mutex_policy types:
+                - hopscotch_hashmap::striping - simple, but the lock array is not resizable
+                - hopscotch_hashmap::refinable - resizable lock array, but more complex access to set data.
+
+                Default is hopscotch_hashmap::striping.
+            */
+            typedef hopscotch_hashmap_ns::striping<>               mutex_policy;
+
+            /// Key equality functor
+            /**
+                Default is <tt>std::equal_to<T></tt>
+            */
+            typedef opt::none                       equal_to;
+
+            /// Key comparison functor
+            /**
+                No default functor is provided. If the option is not specified, the \p less is used.
+            */
+            typedef opt::none                       compare;
+
+            /// specifies binary predicate used for key comparison.
+            /**
+                Default is \p std::less<T>.
+            */
+            typedef opt::none                       less;
+
+            /// Item counter
+            /**
+                The type for item counting feature.
+                Default is cds::atomicity::item_counter
+
+                Only atomic item counter type is allowed.
+            */
+            typedef cds::intrusive::hopscotch_hashset::traits::item_counter   item_counter;
+
+            /// Allocator type
+            /**
+                The allocator type for allocating bucket tables.
+                Default is \p CDS_DEFAULT_ALLOCATOR that is \p std::allocator
+            */
+            typedef CDS_DEFAULT_ALLOCATOR       allocator;
+
+            /// Node allocator type
+            /**
+                If this type is not set explicitly, the \ref allocator type is used.
+            */
+            typedef opt::none                   node_allocator;
+
+            /// Store hash value into items. See hopscotch_hashmap::store_hash for explanation
+            static bool const store_hash = false;
+
+            /// Probe-set type. See \ref probeset_type option for explanation
+            typedef hopscotch_hashmap_ns::list                probeset_type;
+
+            /// Internal statistics
+            typedef empty_stat                  stat;
+        };
+
+        /// Metafunction converting option list to hopscotch hashmap traits
+        /**
+            Template argument list \p Options... are:
+            - \p opt::hash - hash functor tuple, mandatory option. At least, two hash functors should be provided. All hash functor
+                should be orthogonal (different): for each <tt> i,j: i != j => h[i](x) != h[j](x) </tt>.
+                The hash functors are passed as <tt> std::tuple< H1, H2, ... Hn > </tt>. The number of hash functors specifies
+                the number \p k - the count of hash tables in hopscotch hashing.
+            - \p opt::mutex_policy - concurrent access policy.
+                Available policies: \p hopscotch_hashmap::striping, \p hopscotch_hashmap::refinable.
+                Default is \p %hopscotch_hashmap::striping.
+            - \p opt::equal_to - key equality functor like \p std::equal_to.
+                If this functor is defined then the probe-set will be unordered.
+                If \p %opt::compare or \p %opt::less option is specified too, then the probe-set will be ordered
+                and \p %opt::equal_to will be ignored.
+            - \p opt::compare - key comparison functor. No default functor is provided.
+                If the option is not specified, the \p %opt::less is used.
+                If \p %opt::compare or \p %opt::less option is specified, then the probe-set will be ordered.
+            - \p opt::less - specifies binary predicate used for key comparison. Default is \p std::less<T>.
+                If \p %opt::compare or \p %opt::less option is specified, then the probe-set will be ordered.
+            - \p opt::item_counter - the type of item counting feature. Default is \p opt::v::sequential_item_counter.
+            - \p opt::allocator - the allocator type using for allocating bucket tables.
+                Default is \ref CDS_DEFAULT_ALLOCATOR
+            - \p opt::node_allocator - the allocator type using for allocating set's items. If this option
+                is not specified then the type defined in \p %opt::allocator option is used.
+            - \p hopscotch_hashmap::store_hash - this option reserves additional space in the node to store the hash value
+                of the object once it's introduced in the container. When this option is used,
+                the unordered container will store the calculated hash value in the node and rehashing operations won't need
+                to recalculate the hash of the value. This option will improve the performance of unordered containers
+                when rehashing is frequent or hashing the value is a slow operation. Default value is \p false.
+            - \ref intrusive::hopscotch_hashset::probeset_type "hopscotch_hashset::probeset_type" - type of probe set, may be \p hopscotch_hashmap::list or <tt>hopscotch_hashmap::vector<Capacity></tt>,
+                Default is \p hopscotch_hashmap::list.
+            - \p opt::stat - internal statistics. Possibly types: \p hopscotch_hashmap::stat, \p hopscotch_hashmap::empty_stat.
+                Default is \p %hopscotch_hashmap::empty_stat
+        */
+        template <typename... Options>
+        struct make_traits {
+            typedef typename cds::opt::make_options<
+                typename cds::opt::find_type_traits< hopscotch_hashmap_ns::traits, Options... >::type
+                ,Options...
+            >::type   type ;    ///< Result of metafunction
+        };
+    }   // namespace hopscotch_hashmap
+}} // namespace cds::container
+
+#endif  // #ifndef CDSLIB_CONTAINER_DETAILS_HOPSCOTCH_HASHMAP_BASE_H