dlib C++ Library - murmur_hash3_abstract.h

    // Copyright (C) 2011  Davis E. King (davis@dlib.net)
    // License: Boost Software License   See LICENSE.txt for the full license.
    #undef DLIB_MURMUR_HAsH_3_ABSTRACT_Hh_
    #ifdef DLIB_MURMUR_HAsH_3_ABSTRACT_Hh_

    #include "../uintn.h"
    #include <utility>

    namespace dlib
    {

    // ----------------------------------------------------------------------------------------

        uint32 murmur_hash3 (
            const void* key,
            const int len,
            const uint32 seed = 0
        );
        /*!
            requires
                - key == a pointer to a block of memory len bytes long
            ensures
                - returns a 32bit hash of the len bytes pointed to by key.
                - Each value of seed results in a different hash function being used.
                  (e.g. murmur_hash3(key,len,0) should generally not be equal to murmur_hash3(key,len,1))
                - This function is machine architecture agnostic and should always give the same
                  hash value when presented with the same inputs.
                - This hashing algorithm is Austin Appleby's excellent MurmurHash3_x86_32.
                  See: http://code.google.com/p/smhasher/
        !*/

    // ----------------------------------------------------------------------------------------

        inline uint32 murmur_hash3_2 (
            const uint32 v1,
            const uint32 v2
        );
        /*!
            ensures
                - returns a 32bit hash of the two integers given to this function.
                - This function is machine architecture agnostic and should always give the same
                  hash value when presented with the same inputs.
                - This hashing algorithm is Austin Appleby's excellent MurmurHash3_x86_32.
                  See: http://code.google.com/p/smhasher/
        !*/

    // ----------------------------------------------------------------------------------------

        inline uint32 murmur_hash3_3 (
            const uint32 v1,
            const uint32 v2,
            const uint32 v3
        );
        /*!
            ensures
                - returns a 32bit hash of the three integers given to this function.
                - This function is machine architecture agnostic and should always give the same
                  hash value when presented with the same inputs.
                - This hashing algorithm is Austin Appleby's excellent MurmurHash3_x86_32.
                  See: http://code.google.com/p/smhasher/
        !*/

    // ----------------------------------------------------------------------------------------

        std::pair<uint64,uint64> murmur_hash3_128bit (
            const void* key,
            const int len,
            const uint64 seed = 0
        );
        /*!
            requires
                - key == a pointer to a block of memory len bytes long
            ensures
                - returns a 128bit hash (as two 64bit numbers) of the len bytes pointed to by key.
                - Each value of seed results in a different hash function being used.
                  (e.g. murmur_hash3_128bit(key,len,0) should generally not be equal to
                  murmur_hash3_128bit(key,len,1))
                - This function is machine architecture agnostic and should always give the same
                  hash value when presented with the same inputs.
                - This hashing algorithm is Austin Appleby's excellent MurmurHash3_x64_128.
                  See: http://code.google.com/p/smhasher/
        !*/

    // ----------------------------------------------------------------------------------------

        std::pair<uint64,uint64> murmur_hash3_128bit (
            const uint32& v1,
            const uint32& v2,
            const uint32& v3,
            const uint32& v4
        );
        /*!
            ensures
                - returns a 128bit hash (as two 64bit numbers) of the 4 integers given to this
                  function.
                - This function is machine architecture agnostic and should always give the
                  same hash value when presented with the same inputs.
                - This hashing algorithm is Austin Appleby's excellent MurmurHash3_x64_128.
                  See: http://code.google.com/p/smhasher/
        !*/

    // ----------------------------------------------------------------------------------------

        std::pair<uint64,uint64> murmur_hash3_128bit_3 (
            uint64 k1,
            uint64 k2,
            uint64 k3
        );
        /*!
            ensures
                - returns a 128bit hash (as two 64bit numbers) of the 3 integers given to this
                  function.
                - This function is machine architecture agnostic and should always give the
                  same hash value when presented with the same inputs.
                - This hashing algorithm is Austin Appleby's excellent MurmurHash3_x64_128.
                  See: http://code.google.com/p/smhasher/
        !*/

    // ----------------------------------------------------------------------------------------

    }

    #endif // DLIB_MURMUR_HAsH_3_ABSTRACT_Hh_