src/Lib/shttl/simple_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_SIMPLE_HASHER_H
00033 #define SHTTL_SIMPLE_HASHER_H
00034 
00035 #include <limits>
00036 #include <stdexcept>
00037 
00038 #include "hasher.h"
00039 #include "bit.h"
00040 
00041 namespace shttl 
00042 {
00043 
00044     template<class T = int>
00045     class simple_hasher : public hasher<T> 
00046     {
00047     public:
00048 
00049         // Types
00050         typedef simple_hasher<T>    this_type;
00051         typedef hasher<T>           base_type;
00052 
00053         typedef typename base_type::size_type  size_type;
00054         typedef T                              value_type;
00055 
00056         static std::numeric_limits<value_type> value_info;
00057 
00058         // Accessors
00059         size_type size() const  { return m_idx_mask + 1; }
00060 
00061         // Constructors
00062         explicit simple_hasher(const size_type s) :
00063             m_idx_bit ( s ), 
00064             m_idx_mask( (size_type)mask(0, s) )
00065         {
00066             if( s <= 0 || (u64)value_info.max() < (u64)s ){
00067                 throw std::invalid_argument("simple_hasher::simple_hasher");
00068             }
00069         } 
00070 
00071         // Member Functions
00072         size_type index(const T& t) const
00073         {  
00074             return static_cast<size_type>(t) & m_idx_mask;
00075         }
00076 
00077         // tag (bit)
00078         T tag(const T& key) const
00079         {
00080             return key >> m_idx_bit;
00081         }
00082         
00083         // indextagkey
00084         T rebuild(const T& tag, size_type index) const
00085         {
00086             return (T)((tag << m_idx_bit) | index);
00087         }
00088 
00089         bool match( const T& lhs, const T& rhs ) const
00090         {
00091         #ifdef SHTTL_DEBUG
00092             if( size() < (size_type)lhs || size() < (size_type)rhs ){
00093                 throw std::range_error("simple_hasher::match");
00094             }
00095         #endif
00096             return lhs == rhs;
00097         }
00098 
00099     protected:
00100 
00101         size_type  m_idx_bit;
00102         size_type  m_idx_mask;
00103 
00104     };
00105 
00106 } // namespace shttl
00107 
00108 #endif // SHTTL_SIMPLE_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