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 #include "dlink.h"
  36
  37 #if HAVE_OSTREAM
  38 #include <ostream>
  39 #endif
  40
  41 template <class _Arg, class _Result>
  42 struct unary_function {
  43     typedef _Arg argument_type;
  44     typedef _Result result_type;
  45 };
  46
  47 template <class L, class T>
  48 T& for_each(L const &head, T& visitor)
  49 {
  50     for (L const *node = &head; node; node=node->next)
  51         visitor(*node);
  52
  53     return visitor;
  54 }
  55
  56 template <class T>
  57 T& for_each(dlink_list const &collection, T& visitor)
  58 {
  59     for (dlink_node const *node = collection.head; node; node=node->next)
  60         visitor(*(typename T::argument_type const *)node->data);
  61
  62     return visitor;
  63 }
  64
  65 template <class S>
  66 class Stack;
  67
  68 template <class E, class T>
  69 T& for_each(Stack<E> const &collection, T& visitor)
  70 {
  71     for (size_t index = 0; index < collection.count; ++index)
  72         visitor(*(typename T::argument_type const *)collection.items[index]);
  73
  74     return visitor;
  75 };
  76
  77 /* RBC 20030718 - use this to provide instance expecting classes a pointer to a
  78  * singleton
  79  */
  80
  81 template <class C>
  82 class InstanceToSingletonAdapter : public C
  83 {
  84
  85 public:
  86     void *operator new (size_t byteCount) { return ::operator new (byteCount);}
  87
  88     void operator delete (void *address) { ::operator delete (address);}
  89
  90     InstanceToSingletonAdapter(C const *instance) : theInstance (instance) {}
  91
  92     C const * operator-> () const {return theInstance; }
  93
  94     C * operator-> () {return const_cast<C *>(theInstance); }
  95
  96     C const & operator * () const {return *theInstance; }
  97
  98     C & operator * () {return *const_cast<C *>(theInstance); }
  99
 100     operator C const * () const {return theInstance;}
 101
 102     operator C *() {return const_cast<C *>(theInstance);}
 103
 104 private:
 105     C const *theInstance;
 106 };
 107
 108 template <class InputIterator , class Visitor>
 109 Visitor& for_each(InputIterator from, InputIterator to, Visitor& visitor)
 110 {
 111     while (!(from == to)) {
 112         typename InputIterator::value_type &value = *from;
 113         ++from;
 114         visitor(value);
 115     }
 116
 117     return visitor;
 118 }
 119
 120 /* generic ostream printer */
 121 template <class Pointer>
 122 struct PointerPrinter {
 123     PointerPrinter(std::ostream &astream, std::string aDelimiter) : os(astream), delimiter (aDelimiter) {}
 124
 125     void operator () (Pointer aNode) {
 126         os << *aNode << delimiter;
 127     }
 128
 129     std::ostream &os;
 130     std::string delimiter;
 131 };
 132
 133 #endif /* SQUID_GENERIC_H */