objmap.h

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00001 // Copyright (C) 2001-2005 Open Source Telecom Corporation.
00002 // Copyright (C) 2006-2008 David Sugar, Tycho Softworks.
00003 //
00004 // This program is free software; you can redistribute it and/or modify
00005 // it under the terms of the GNU General Public License as published by
00006 // the Free Software Foundation; either version 2 of the License, or
00007 // (at your option) any later version.
00008 //
00009 // This program is distributed in the hope that it will be useful,
00010 // but WITHOUT ANY WARRANTY; without even the implied warranty of
00011 // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
00012 // GNU General Public License for more details.
00013 //
00014 // You should have received a copy of the GNU General Public License
00015 // along with this program; if not, write to the Free Software
00016 // Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
00017 //
00018 // As a special exception to the GNU General Public License, permission is
00019 // granted for additional uses of the text contained in its release
00020 // of Common C++.
00021 //
00022 // The exception is that, if you link the Common C++ library with other
00023 // files to produce an executable, this does not by itself cause the
00024 // resulting executable to be covered by the GNU General Public License.
00025 // Your use of that executable is in no way restricted on account of
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00027 //
00028 // This exception does not however invalidate any other reasons why
00029 // the executable file might be covered by the GNU General Public License.
00030 //
00031 // This exception applies only to the code released under the
00032 // name Common C++.  If you copy code from other releases into a copy of
00033 // Common C++, as the General Public License permits, the exception does
00034 // not apply to the code that you add in this way.  To avoid misleading
00035 // anyone as to the status of such modified files, you must delete
00036 // this exception notice from them.
00037 //
00038 // If you write modifications of your own for Common C++, it is your choice
00039 // whether to permit this exception to apply to your modifications.
00040 // If you do not wish that, delete this exception notice.
00041 
00047 #include <cc++/strchar.h>
00048 
00049 namespace ost {
00050 
00059 template <class T, class K, unsigned S>
00060 class objMap {
00061 protected:
00062         static T *objIndex[S];
00063         T* objNext;
00064         const K objKey;
00065 
00066         virtual unsigned keyIndex(K k) 
00067         {
00068                 unsigned idx = 0;
00069                 unsigned char *p = (unsigned char *)&k;
00070                 unsigned len = sizeof(K);
00071 
00072                 while(len--) {
00073                         idx ^= (idx << 1) ^ *p;
00074                         ++p;
00075                 }
00076                 return idx % S;
00077         }
00078 
00079         inline unsigned getSize(void) 
00080                 {return S;}
00081 
00082         objMap(const K key) 
00083         {
00084                 unsigned idx = keyIndex(key);
00085                 objKey = key;
00086                 objNext = objIndex[idx];
00087                 objIndex[idx] = (T *)this;
00088         }
00089 public:
00090         static T *getObject(keystring key);
00091 };
00092 
00093 template <class T, unsigned S>
00094 class keyMap : public objMap<T, keystring, S>
00095 {
00096         keyMap(keystring key) : objMap<T, keystring, S>(key) {};
00097 
00098         unsigned keyIndex(keystring k) 
00099         {
00100                 unsigned idx = 0;
00101                 while(*k) {
00102                         idx = (idx << 1) ^ (unsigned)*k;
00103                         ++k;
00104                 }
00105                 return idx % S;
00106         }
00107 };
00108 
00109 template <class T, class K, unsigned S>
00110 T *objMap<T, K, S>::objIndex[S](0);
00111 
00112 template <class T, class K, unsigned S>
00113 T *objMap<T, K, S>::getObject(const keystring key)
00114 {
00115         T *obj = objIndex[keyIndex(key)];
00116         while(obj) {
00117                 if(key == obj->objKey)
00118                         break;
00119                 obj = obj->objNext;
00120         }
00121         return obj;
00122 }
00123 
00124 } // namespace

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