text: /*
   * Copyright (c) 2019 Inria
   * Copyright (c) 1999-2008 Mark D. Hill and David A. Wood
   * All rights reserved.
   *
   * 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;
   * neither the name of the copyright holders nor the names of its
   * contributors may be used to endorse or promote products derived from
   * this software without specific prior written permission.
   *
   * 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
   * OWNER 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.
   *
   * Authors: Daniel Carvalho
   */
  
  #ifndef __BASE_FILTERS_MULTI_BIT_SEL_BLOOM_FILTER_HH__
  #define __BASE_FILTERS_MULTI_BIT_SEL_BLOOM_FILTER_HH__
  
  #include "base/filters/base.hh"
  
  struct BloomFilterMultiBitSelParams;
  
  namespace BloomFilter {
  
  /**
   * The MultiBitSel Bloom Filter associates an address to multiple entries
   * through the use of multiple hash functions.
   */
  class MultiBitSel : public Base
  {
    public:
      MultiBitSel(const BloomFilterMultiBitSelParams* p);
      ~MultiBitSel();
  
      void set(Addr addr) override;
      int getCount(Addr addr) const override;
  
    protected:
      /**
       * Apply the selected the hash functions to an address.
       *
       * @param addr The address to hash.
       * @param hash_number Index of the hash function to be used.
       */
      virtual int hash(Addr addr, int hash_number) const;
  
      /** Number of hashes. */
      const int numHashes;
  
      /** Size of the filter when doing parallel hashing. */
      const int parFilterSize;
  
      /** Whether hashing should be performed in parallel. */
      const bool isParallel;
  
    private:
      /**
       * Bit offset from block number. Used to simulate bit selection hashing
       * on larger than cache-line granularities, by skipping some bits.
       */
      const int skipBits;
  };
  
  } // namespace BloomFilter
  
  #endif // __BASE_FILTERS_MULTI_BIT_SEL_BLOOM_FILTER_HH__
  