src/Generic.h

   1 /*
   2  * $Id$
   3  *
   4  *
   5  * SQUID Web Proxy Cache          http://www.squid-cache.org/
   6  * ----------------------------------------------------------
   7  *
   8  *  Squid is the result of efforts by numerous individuals from
   9  *  the Internet community; see the CONTRIBUTORS file for full
  10  *  details.   Many organizations have provided support for Squid's
  11  *  development; see the SPONSORS file for full details.  Squid is
  12  *  Copyrighted (C) 2001 by the Regents of the University of
  13  *  California; see the COPYRIGHT file for full details.  Squid
  14  *  incorporates software developed and/or copyrighted by other
  15  *  sources; see the CREDITS file for full details.
  16  *
  17  *  This program is free software; you can redistribute it and/or modify
  18  *  it under the terms of the GNU General Public License as published by
  19  *  the Free Software Foundation; either version 2 of the License, or
  20  *  (at your option) any later version.
  21  *
  22  *  This program is distributed in the hope that it will be useful,
  23  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
  24  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  25  *  GNU General Public License for more details.
  26  *
  27  *  You should have received a copy of the GNU General Public License
  28  *  along with this program; if not, write to the Free Software
  29  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111, USA.
  30  *
  31  */
  32 #ifndef SQUID_GENERIC_H
  33 #define SQUID_GENERIC_H
  34
  35 /** \todo CLEANUP: checks towrap this header properly */
  36 #include <ostream>
  37
  38 #include "dlink.h"
  39
  40 template <class _Arg, class _Result>
  41 struct unary_function {
  42     typedef _Arg argument_type;
  43     typedef _Result result_type;
  44 };
  45
  46 template <class L, class T>
  47 T& for_each(L const &head, T& visitor)
  48 {
  49     for (L const *node = &head; node; node=node->next)
  50         visitor(*node);
  51
  52     return visitor;
  53 }
  54
  55 template <class T>
  56 T& for_each(dlink_list const &collection, T& visitor)
  57 {
  58     for (dlink_node const *node = collection.head; node; node=node->next)
  59         visitor(*(typename T::argument_type const *)node->data);
  60
  61     return visitor;
  62 }
  63
  64 template <class S>
  65 class Stack;
  66
  67 template <class E, class T>
  68 T& for_each(Stack<E> const &collection, T& visitor)
  69 {
  70     for (size_t index = 0; index < collection.count; ++index)
  71         visitor(*(typename T::argument_type const *)collection.items[index]);
  72
  73     return visitor;
  74 };
  75
  76 /* RBC 20030718 - use this to provide instance expecting classes a pointer to a
  77  * singleton
  78  */
  79
  80 template <class C>
  81 class InstanceToSingletonAdapter : public C
  82 {
  83
  84 public:
  85     void *operator new (size_t byteCount) { return ::operator new (byteCount);}
  86
  87     void operator delete (void *address) { ::operator delete (address);}
  88
  89     InstanceToSingletonAdapter(C const *instance) : theInstance (instance) {}
  90
  91     C const * operator-> () const {return theInstance; }
  92
  93     C * operator-> () {return const_cast<C *>(theInstance); }
  94
  95     C const & operator * () const {return *theInstance; }
  96
  97     C & operator * () {return *const_cast<C *>(theInstance); }
  98
  99     operator C const * () const {return theInstance;}
 100
 101     operator C *() {return const_cast<C *>(theInstance);}
 102
 103 private:
 104     C const *theInstance;
 105 };
 106
 107 template <class InputIterator , class Visitor>
 108 Visitor& for_each(InputIterator from, InputIterator to, Visitor& visitor)
 109 {
 110     while (!(from == to)) {
 111         typename InputIterator::value_type &value = *from;
 112         ++from;
 113         visitor(value);
 114     }
 115
 116     return visitor;
 117 }
 118
 119 /* generic ostream printer */
 120 template <class Pointer>
 121 struct PointerPrinter {
 122     PointerPrinter(std::ostream &astream, std::string aDelimiter) : os(astream), delimiter (aDelimiter) {}
 123
 124     void operator () (Pointer aNode) {
 125         os << *aNode << delimiter;
 126     }
 127
 128     std::ostream &os;
 129     std::string delimiter;
 130 };
 131
 132 #endif /* SQUID_GENERIC_H */