include/Util.h

   1 /***************************************************************************
   2  *   Copyright (C) 2007 by Prabakaran Thirumalai   *
   3  *   praba_tuty@yahoo.com   *
   4  *                                                                         *
   5  *   This program is free software; you can redistribute it and/or modify  *
   6  *   it under the terms of the GNU General Public License as published by  *
   7  *   the Free Software Foundation; either version 2 of the License, or     *
   8  *   (at your option) any later version.                                   *
   9  *                                                                         *
  10  *   This program is distributed in the hope that it will be useful,       *
  11  *   but WITHOUT ANY WARRANTY; without even the implied warranty of        *
  12  *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the         *
  13  *   GNU General Public License for more details.                          *
  14  *                                                                         *
  15   ***************************************************************************/
  16 #ifndef UTIL_H
  17 #define UTIL_H
  18 #include<ErrorType.h>
  19 #include<Debug.h>
  20 class ListNode
  21 {
  22     public:
  23     void *element;
  24     ListNode *next;
  25
  26 };
  27
  28 class ListIterator
  29 {
  30     ListNode *iter;
  31     ListNode *start;
  32     ListIterator();
  33     public:
  34
  35     ListIterator(ListNode *head) { iter = head; start = head; }
  36
  37     bool hasElement()
  38     {
  39         if (iter == NULL) return false; else return true;
  40     }
  41
  42     void reset()
  43     {
  44         iter = start;
  45     }
  46     //isRemove ->the node needs to deleted after returning
  47     void* nextElement(bool isRemove = false)
  48     {
  49         if (iter == NULL) return NULL;
  50         ListNode *node = iter;
  51         iter = iter ->next;
  52         return node->element;
  53     }
  54 };
  55
  56 class Identifier
  57 {
  58     public:
  59     char name[IDENTIFIER_LENGTH];
  60 };
  61
  62 class List
  63 {
  64     ListNode *head;
  65     public:
  66     List() { head = NULL;}
  67
  68     DbRetVal append(void *elem)
  69     {
  70         ListNode *newNode = new ListNode();
  71         newNode->element = elem;
  72         newNode->next = NULL;
  73         //If this is the first node, set it as head
  74         if (NULL == head) { head = newNode; return OK; }
  75
  76         ListNode *iter = head;
  77         while (NULL != iter->next) iter = iter->next;
  78         iter->next = newNode;
  79         return OK;
  80     }
  81     //Warning:Try to avoid using this method while using the iterator.The behavior
  82     //is undefined. Instead set flag isRemove to yes and call nextElement of iterator.
  83     DbRetVal remove(void *elem)
  84     {
  85         if (NULL == head)
  86         {
  87             printError(ErrNotExists, "There are no elements in the list. Empty list");
  88             return ErrNotExists;
  89         }
  90         ListNode *iter = head, *prev = head;
  91         while (iter->next != NULL)
  92         {
  93             if (elem == iter->element)
  94             {
  95                 prev->next = iter->next;
  96                 delete iter;
  97             }
  98             prev = iter;
  99             iter = iter->next;
 100         }
 101         if( iter == head) // there is only one node in the list
 102         {
 103             if (elem == iter->element)
 104             {
 105                 delete head;
 106                 head = NULL;
 107                 return OK;
 108             }
 109
 110         }
 111         if( prev == head) // there are only two node in the list
 112         {
 113             if (elem == iter->element)
 114             {
 115                 head->next = NULL;
 116                 delete iter;
 117                 return OK;
 118             }
 119         }
 120         printError(ErrNotFound, "There are no elements in the list");
 121         return ErrNotFound;
 122     }
 123
 124     ListIterator getIterator()
 125     {
 126         ListIterator iter(head);
 127         return iter;
 128     }
 129     void reset()
 130     {
 131         if (NULL == head) return;
 132         ListNode *iter = head, *prevIter = head;
 133         while (iter->next != NULL)
 134         {
 135             prevIter = iter;
 136             iter = iter->next;
 137             delete prevIter;
 138
 139         }
 140         delete iter;
 141         head = NULL;
 142         return;
 143     }
 144     int size()
 145     {
 146         int count =1;
 147         if (NULL == head) return 0;
 148         ListNode *iter = head;
 149         while (iter->next != NULL)
 150         {
 151             count++;
 152             iter = iter->next;
 153         }
 154         return count;
 155     }
 156
 157 };
 158 #endif