src/Lib/shttl/std_hasher.h

説明を見る。
00001 // 
00002 // Copyright (c) 2005-2008 Kenichi Watanabe.
00003 // Copyright (c) 2005-2008 Yasuhiro Watari.
00004 // Copyright (c) 2005-2008 Hironori Ichibayashi.
00005 // Copyright (c) 2008-2009 Kazuo Horio.
00006 // Copyright (c) 2009-2013 Naruki Kurata.
00007 // Copyright (c) 2005-2013 Ryota Shioya.
00008 // Copyright (c) 2005-2013 Masahiro Goshima.
00009 // 
00010 // This software is provided 'as-is', without any express or implied
00011 // warranty. In no event will the authors be held liable for any damages
00012 // arising from the use of this software.
00013 // 
00014 // Permission is granted to anyone to use this software for any purpose,
00015 // including commercial applications, and to alter it and redistribute it
00016 // freely, subject to the following restrictions:
00017 // 
00018 // 1. The origin of this software must not be misrepresented; you must not
00019 // claim that you wrote the original software. If you use this software
00020 // in a product, an acknowledgment in the product documentation would be
00021 // appreciated but is not required.
00022 // 
00023 // 2. Altered source versions must be plainly marked as such, and must not be
00024 // misrepresented as being the original software.
00025 // 
00026 // 3. This notice may not be removed or altered from any source
00027 // distribution.
00028 // 
00029 // 
00030 
00031 
00032 #ifndef SHTTL_STD_HASHER_H
00033 #define SHTTL_STD_HASHER_H
00034 
00035 #include "bit.h"
00036 #include "hasher.h"
00037 #include <limits>
00038 #include <stdexcept>
00039 
00040 namespace shttl
00041 {
00042     template<class T = size_t>
00043     class std_hasher : public hasher<T> {
00044     public:
00045         // --
00046 
00047         typedef shttl::hasher<T> base_type;
00048         typedef std_hasher<T>    this_type;
00049 
00050         typedef typename base_type::size_type  size_type;
00051         typedef T                          value_type;
00052 
00053         static const std::numeric_limits<value_type> value_info;
00054         
00055 
00056         // Accessors
00057 
00058         size_type  idx_bit()  const { return m_idx_bit;          }
00059         value_type idx_mask() const { return m_idx_mask;         }
00060         size_type  off_bit()  const { return m_off_bit;          }
00061         value_type off_mask() const { return m_off_mask;         }
00062 
00063         // size() returns maximum value of index()
00064         size_type  size()     const { return (size_type)(idx_mask() + 1); }
00065 
00066 
00067         // Constructor(s)
00068         explicit std_hasher(const size_type idx_bit_arg, const size_type off_bit_arg) :
00069             m_idx_bit ( idx_bit_arg ), 
00070             m_idx_mask( (value_type)mask(0, idx_bit_arg) ),
00071             m_off_bit ( off_bit_arg), 
00072             m_off_mask( (value_type)mask(0, off_bit_arg ) 
00073         ){
00074             if(( (size_type)value_info.digits < idx_bit() ) ||
00075                ( (size_type)value_info.digits < off_bit() ) ||
00076                ( (size_type)value_info.digits < idx_bit() + off_bit() )
00077             ){
00078                 throw std::invalid_argument("std_hasher::std_hasher");
00079             }
00080         }
00081 
00082         ~std_hasher() 
00083         {
00084         }
00085 
00086         // Member Functions
00087         size_type index(const value_type& t) const 
00088         {
00089             return (size_type)((t >> off_bit()) & idx_mask());
00090         }
00091 
00092         value_type tag(const value_type& t) const
00093         {
00094             return t >> (off_bit()+idx_bit());
00095         }
00096 
00097         value_type rebuild(const value_type& tag, size_type index) const 
00098         {
00099             return static_cast<value_type>( ((tag << idx_bit()) | index) << off_bit() );
00100         }
00101 
00102         bool match(const value_type& lhs, const value_type& rhs) const 
00103         {
00104             return (lhs & ~off_mask()) == (rhs & ~off_mask());
00105         }
00106 
00107     protected:
00108         size_type   m_idx_bit;
00109         value_type  m_idx_mask;
00110         size_type   m_off_bit;
00111         value_type  m_off_mask;
00112 
00113     };
00114 
00115 } // namespace shttl
00116 
00117 #endif // SHTTL_STD_HASHER_H

Onikiri2に対してTue Jun 18 14:34:21 2013に生成されました。  doxygen 1.4.7