src/Generic.h

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