jenkins.h

00001 ///\file
00002 
00003 /******************************************************************************
00004 The MIT License(MIT)
00005 
00006 Embedded Template Library.
00007 https://github.com/ETLCPP/etl
00008 http://www.etlcpp.com
00009 
00010 Copyright(c) 2014 jwellbelove
00011 
00012 Permission is hereby granted, free of charge, to any person obtaining a copy
00013 of this software and associated documentation files(the "Software"), to deal
00014 in the Software without restriction, including without limitation the rights
00015 to use, copy, modify, merge, publish, distribute, sublicense, and / or sell
00016 copies of the Software, and to permit persons to whom the Software is
00017 furnished to do so, subject to the following conditions :
00018 
00019 The above copyright notice and this permission notice shall be included in all
00020 copies or substantial portions of the Software.
00021 
00022 THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
00023 IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
00024 FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.IN NO EVENT SHALL THE
00025 AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
00026 LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
00027 OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
00028 SOFTWARE.
00029 ******************************************************************************/
00030 
00031 #ifndef __ETL_JENKINS__
00032 #define __ETL_JENKINS__
00033 
00034 #include <stdint.h>
00035 #include <iterator>
00036 
00037 #include "platform.h "
00038 #include "static_assert.h"
00039 #include "type_traits.h "
00040 #include "error_handler.h "
00041 #include "ihash.h "
00042 #include "frame_check_sequence.h "
00043 
00044 #if defined(ETL_COMPILER_KEIL)
00045 #pragma diag_suppress 1300
00046 #endif
00047 
00048 ///\defgroup jenkins Jenkins 32 hash calculation
00049 ///\ingroup maths
00050 
00051 namespace etl
00052 {
00053   //***************************************************************************
00054   /// Jenkins policy.
00055   /// Calculates 32 bit Jenkins hash.
00056   //***************************************************************************
00057   struct jenkins_policy
00058   {
00059     typedef uint32_t value_type;
00060 
00061     inline uint32_t initial()
00062     {
00063       is_finalised = false;
00064 
00065       return 0;
00066     }
00067 
00068     inline uint32_t add(value_type hash, uint8_t value) const
00069     {
00070       ETL_ASSERT(!is_finalised, ETL_ERROR(hash_finalised));
00071 
00072       hash += value;
00073       hash += (hash << 10);
00074       hash ^= (hash >> 6);
00075 
00076       return hash;
00077     }
00078 
00079     inline uint32_t final(value_type hash)
00080     {
00081       hash += (hash << 3);
00082       hash ^= (hash >> 11);
00083       hash += (hash << 15);
00084       is_finalised = true;
00085 
00086       return hash;
00087     }
00088 
00089     bool is_finalised;
00090   };
00091 
00092   //*************************************************************************
00093   /// jenkins
00094   //*************************************************************************
00095   class jenkins : public etl::frame_check_sequence<etl::jenkins_policy>
00096   {
00097   public:
00098 
00099     //*************************************************************************
00100     /// Default constructor.
00101     //*************************************************************************
00102     jenkins()
00103     {
00104       this->reset();
00105     }
00106 
00107     //*************************************************************************
00108     /// Constructor from range.
00109     /// \param begin Start of the range.
00110     /// \param end   End of the range.
00111     //*************************************************************************
00112     template<typename TIterator>
00113     jenkins(TIterator begin, const TIterator end)
00114     {
00115       this->reset();
00116       this->add(begin, end);
00117     }
00118   };
00119 }
00120 
00121 #endif
00122