src/Lib/shttl/static_off_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_STATIC_OFF_HASHER_H
00033 #define SHTTL_STATIC_OFF_HASHER_H
00034 
00035 #include <stdexcept>
00036 #include <iostream>
00037 
00038 #include "bit.h"
00039 #include "hasher.h"
00040 
00041 namespace shttl 
00042 {
00043 
00044     template<class T = u32, size_t OFFSET = 0>      // Offset bits
00045     class static_off_hasher : public hasher<T> {
00046     public:
00047 
00048         // Types
00049         typedef static_off_hasher<T, OFFSET>    this_type;
00050         typedef hasher<T>               base_type;
00051 
00052         typedef typename base_type::size_type  size_type;
00053         typedef T                              value_type;
00054 
00055         static const std::numeric_limits<value_type> value_info;
00056 
00057         // Accessors
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 OFFSET;                 }
00061         u64        off_mask() const { return shttl::mask(0, OFFSET); }
00062 
00063         // size() returns maximum value of index()
00064         size_type size() const 
00065         {
00066             return (size_type)idx_mask() + 1; 
00067         }
00068 
00069         // Constructor(s)
00070         explicit static_off_hasher(const size_type index_bit_size) :
00071             m_idx_bit ( index_bit_size ), 
00072             m_idx_mask( (value_type)shttl::mask(0, index_bit_size) )
00073         {
00074             if( (/*idx_bit() < 0 || */(size_type)value_info.digits < idx_bit()) ||
00075                 (/*off_bit() < 0 || */(size_type)value_info.digits < off_bit()) ||
00076                 (                 (size_type)value_info.digits < idx_bit() + off_bit()  )
00077             ){
00078                 throw std::invalid_argument("static_off_hasher::static_off_hasher");  
00079             }
00080         }
00081 
00082 
00083         // Member Functions
00084         size_type index(const T& t) const  
00085         {
00086             return static_cast<size_type>((t >> off_bit()) & idx_mask());
00087         }
00088 
00089         T tag(const T& t) const
00090         {
00091             return t >> (off_bit()+idx_bit());
00092         }
00093 
00094         value_type rebuild(const value_type& tag, size_type index) const 
00095         {
00096             return (value_type)(
00097                 ((tag << idx_bit()) | index) << off_bit()
00098             );
00099         }
00100 
00101         bool match(const T& lhs, const T& rhs) const 
00102         {
00103             return (lhs & ~off_mask()) == (rhs & ~off_mask());
00104         }
00105 
00106     protected:
00107 
00108         size_type   m_idx_bit;
00109         value_type  m_idx_mask;
00110 
00111     };
00112 
00113 } // namespace shttl
00114 
00115 #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