Fixed minor compiler warning
[libcds.git] / cds / intrusive / details / feldman_hashset_base.h
index 4d1087c42e0bcc1e83d76581f77f727bd1368070..691e2af3b4af4fc9f82a20fd9ea27f35f2c223d0 100644 (file)
@@ -1,4 +1,32 @@
-//$$CDS-header$$
+/*
+    This file is a part of libcds - Concurrent Data Structures library
+
+    (C) Copyright Maxim Khizhinsky (libcds.dev@gmail.com) 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_INTRUSIVE_DETAILS_FELDMAN_HASHSET_BASE_H
 #define CDSLIB_INTRUSIVE_DETAILS_FELDMAN_HASHSET_BASE_H
@@ -33,6 +61,37 @@ namespace cds { namespace intrusive {
             //@endcond
         };
 
+        /// Hash size option
+        /**
+            @copydetails traits::hash_size
+        */
+        template <size_t Size>
+        struct hash_size {
+            //@cond
+            template <typename Base> struct pack: public Base
+            {
+                enum: size_t {
+                    hash_size = Size
+                };
+            };
+            //@endcond
+        };
+
+        /// Hash splitter option
+        /**
+            @copydetails traits::hash_splitter
+        */
+        template <typename Splitter>
+        struct hash_splitter {
+            //@cond
+            template <typename Base> struct pack: public Base
+            {
+                typedef Splitter hash_splitter;
+            };
+            //@endcond
+        };
+
+
         /// \p FeldmanHashSet internal statistics
         template <typename EventCounter = cds::atomicity::event_counter>
         struct stat {
@@ -135,6 +194,32 @@ namespace cds { namespace intrusive {
             */
             typedef cds::opt::none hash_accessor;
 
+            /// The size of hash value in bytes
+            /**
+                By default, the size of hash value is <tt>sizeof( hash_type )</tt>.
+                Sometimes it is not correct, for example, for that 6-byte struct \p static_assert will be thrown:
+                \code
+                struct key_type {
+                    uint32_t    key1;
+                    uint16_t    subkey;
+                };
+
+                static_assert( sizeof( key_type ) == 6, "Key type size mismatch" );
+                \endcode
+                For that case you can specify \p hash_size explicitly.
+
+                Value \p 0 means <tt>sizeof( hash_type )</tt>.
+            */
+            static CDS_CONSTEXPR size_t const hash_size = 0;
+
+            /// Hash splitter
+            /**
+                This trait specifies hash bit-string splitter algorithm.
+                By default, \p cds::algo::number_splitter is used if \p HashType is a number,
+                \p cds::algo::split_bitstring otherwise.
+            */
+            typedef cds::opt::none hash_splitter;
+
             /// Disposer for removing data nodes
             typedef cds::intrusive::opt::v::empty_disposer disposer;
 
@@ -164,7 +249,7 @@ namespace cds { namespace intrusive {
 
             /// Array node allocator
             /**
-                Allocator for array nodes. That allocator is used for creating \p headNode and \p arrayNode when the set grows.
+                Allocator for array nodes. The allocator is used for creating \p headNode and \p arrayNode when the set grows.
                 Default is \ref CDS_DEFAULT_ALLOCATOR
             */
             typedef CDS_DEFAULT_ALLOCATOR node_allocator;
@@ -198,6 +283,10 @@ namespace cds { namespace intrusive {
             Supported \p Options are:
             - \p feldman_hashset::hash_accessor - mandatory option, hash accessor functor.
                 @copydetails traits::hash_accessor
+            - \p feldman_hashset::hash_size - the size of hash value in bytes.
+                @copydetails traits::hash_size
+            - \p feldman_hashset::hash_splitter - a hash splitter algorithm
+                @copydetails traits::hash_splitter
             - \p opt::node_allocator - array node allocator.
                 @copydetails traits::node_allocator
             - \p opt::compare - hash comparison functor. No default functor is provided.
@@ -272,8 +361,8 @@ namespace cds { namespace intrusive {
 
         //@cond
         namespace details {
-            template <typename HashType, typename UInt = size_t >
-            using hash_splitter = cds::algo::split_bitstring< HashType, UInt >;
+            template <typename HashType, size_t HashSize >
+            using hash_splitter = cds::algo::split_bitstring< HashType, HashSize >;
 
             struct metrics {
                 size_t  head_node_size;     // power-of-two
@@ -326,10 +415,9 @@ namespace cds { namespace intrusive {
             /// Hash type deduced from \p hash_accessor return type
             typedef typename std::decay<
                 typename std::remove_reference<
-                decltype(hash_accessor()(std::declval<value_type>()))
+                    decltype(hash_accessor()(std::declval<value_type>()))
                 >::type
             >::type hash_type;
-            //typedef typename std::result_of< hash_accessor( std::declval<value_type>()) >::type hash_type;
             static_assert(!std::is_pointer<hash_type>::value, "hash_accessor should return a reference to hash value");
 
             typedef typename cds::opt::details::make_comparator_from<
@@ -338,7 +426,14 @@ namespace cds { namespace intrusive {
                 feldman_hashset::bitwise_compare< hash_type >
             >::type hash_comparator;
 
-            typedef feldman_hashset::details::hash_splitter< hash_type > hash_splitter;
+            /// The size of hash_type in bytes, see \p traits::hash_size for explanation
+            static CDS_CONSTEXPR size_t const c_hash_size = traits::hash_size == 0 ? sizeof( hash_type ) : static_cast<size_t>( traits::hash_size );
+
+            typedef typename std::conditional<
+                std::is_same< typename traits::hash_splitter, cds::opt::none >::value,
+                typename cds::algo::select_splitter< hash_type, c_hash_size >::type,
+                typename traits::hash_splitter
+            >::type hash_splitter;
 
             enum node_flags {
                 flag_array_converting = 1,   ///< the cell is converting from data node to an array node
@@ -370,8 +465,7 @@ namespace cds { namespace intrusive {
             struct traverse_data {
                 hash_splitter splitter;
                 array_node * pArr;
-                size_t nOffset;
-                size_t nSlot;
+                typename hash_splitter::uint_type nSlot;
                 size_t nHeight;
 
                 traverse_data( hash_type const& hash, multilevel_array& arr )
@@ -384,8 +478,8 @@ namespace cds { namespace intrusive {
                 {
                     splitter.reset();
                     pArr = arr.head();
-                    nOffset = arr.metrics().head_node_size_log;
-                    nSlot = splitter.cut( arr.metrics().head_node_size_log );
+                    nSlot = splitter.cut( static_cast<unsigned>( arr.metrics().head_node_size_log ));
+                    assert( static_cast<size_t>( nSlot ) < arr.metrics().head_node_size );
                     nHeight = 1;
                 }
             };
@@ -397,14 +491,17 @@ namespace cds { namespace intrusive {
 
         public:
             multilevel_array(size_t head_bits, size_t array_bits )
-                : m_Metrics(feldman_hashset::details::metrics::make(head_bits, array_bits, sizeof(hash_type)))
+                : m_Metrics(feldman_hashset::details::metrics::make( head_bits, array_bits, c_hash_size ))
                 , m_Head( alloc_head_node())
-            {}
+            {
+                assert( hash_splitter::is_correct( static_cast<unsigned>( metrics().head_node_size_log )));
+                assert( hash_splitter::is_correct( static_cast<unsigned>( metrics().array_node_size_log )));
+            }
 
             ~multilevel_array()
             {
                 destroy_tree();
-                free_array_node(m_Head);
+                free_array_node( m_Head, head_size());
             }
 
             node_ptr traverse(traverse_data& pos)
@@ -412,14 +509,13 @@ namespace cds { namespace intrusive {
                 back_off bkoff;
                 while (true) {
                     node_ptr slot = pos.pArr->nodes[pos.nSlot].load(memory_model::memory_order_acquire);
-                    if (slot.bits() == flag_array_node) {
+                    if ( slot.bits() == flag_array_node ) {
                         // array node, go down the tree
                         assert(slot.ptr() != nullptr);
                         assert( !pos.splitter.eos());
-                        pos.nSlot = pos.splitter.cut( metrics().array_node_size_log );
+                        pos.nSlot = pos.splitter.cut( static_cast<unsigned>( metrics().array_node_size_log ));
                         assert( pos.nSlot < metrics().array_node_size );
                         pos.pArr = to_array(slot.ptr());
-                        pos.nOffset += metrics().array_node_size_log;
                         ++pos.nHeight;
                     }
                     else if (slot.bits() == flag_array_converting) {
@@ -479,8 +575,8 @@ namespace cds { namespace intrusive {
                 for (atomic_node_ptr * p = pArr->nodes, *pLast = p + nSize; p != pLast; ++p) {
                     node_ptr slot = p->load(memory_model::memory_order_relaxed);
                     if (slot.bits() == flag_array_node) {
-                        destroy_array_nodes(to_array(slot.ptr()), array_node_size());
-                        free_array_node(to_array(slot.ptr()));
+                        destroy_array_nodes( to_array(slot.ptr()), array_node_size());
+                        free_array_node( to_array( slot.ptr()), array_node_size());
                         p->store(node_ptr(), memory_model::memory_order_relaxed);
                     }
                 }
@@ -503,9 +599,9 @@ namespace cds { namespace intrusive {
                 return alloc_array_node(array_node_size(), pParent, idxParent);
             }
 
-            static void free_array_node(array_node * parr)
+            static void free_array_node( array_node * parr, size_t /*nSize*/ )
             {
-                cxx_array_node_allocator().Delete(parr);
+                cxx_array_node_allocator().Delete( parr, 1 );
             }
 
             union converter {
@@ -554,9 +650,8 @@ namespace cds { namespace intrusive {
 
             bool expand_slot( traverse_data& pos, node_ptr current)
             {
-                bool bRet = expand_slot( pos.pArr, pos.nSlot, current, pos.nOffset );
-                //pos.reset( *this );
-                return bRet;
+                assert( !pos.splitter.eos() );
+                return expand_slot( pos.pArr, pos.nSlot, current, pos.splitter.bit_offset());
             }
 
         private:
@@ -572,11 +667,12 @@ namespace cds { namespace intrusive {
                 if (!slot.compare_exchange_strong(cur, cur | flag_array_converting, memory_model::memory_order_release, atomics::memory_order_relaxed))
                 {
                     stats().onExpandNodeFailed();
-                    free_array_node(pArr);
+                    free_array_node( pArr, array_node_size());
                     return false;
                 }
 
-                size_t idx = hash_splitter( hash_accessor()(*current.ptr()), nOffset ).cut( m_Metrics.array_node_size_log );
+                typename hash_splitter::uint_type idx = hash_splitter( hash_accessor()(*current.ptr()), nOffset ).cut( 
+                    static_cast<unsigned>( m_Metrics.array_node_size_log ));
                 pArr->nodes[idx].store(current, memory_model::memory_order_release);
 
                 cur = cur | flag_array_converting;