Initial revision

buddy/examples/bddcalc/hashtbl.cxx

@@ -0,0 +1,174 @@
+/*************************************************************************
+  $Header: /Volumes/CVS/repository/spot/spot/buddy/examples/bddcalc/hashtbl.cxx,v 1.1 2004/06/28 14:19:59 adl Exp $
+  FILE:  hashtbl.cc
+  DESCR: Compiler hash table
+  AUTH:  Jorn Lind
+  DATE:  (C) september 1998
+*************************************************************************/
+#include "hashtbl.h"
+
+/*************************************************************************
+*************************************************************************/
+
+/*======================================================================*/
+
+hashTable::hashTable(void)
+{
+   table = NULL;
+   clear();
+}
+
+
+hashTable::~hashTable(void)
+{
+   delete[] table;
+}
+
+
+void hashTable::add(hashData &d)
+{
+   if (freepos == -1)
+      reallocate_table();
+
+   unsigned int h = hashval(d.id);
+   int tmppos = table[freepos].next;
+
+   table[freepos].data = d;
+   table[freepos].next = table[h].first;
+   table[h].first = freepos;
+   freepos = tmppos;
+}
+
+
+int hashTable::exists(const char *id)
+{
+   if (size == 0)
+      return 0;
+   
+   int p = table[hashval(id)].first;
+   
+   while (p != -1)
+   {
+      if (strcmp(id, table[p].data.id) == 0)
+         return 1;
+      p = table[p].next;
+   }
+
+   return 0;
+}
+
+
+int hashTable::lookup(const char *id, hashData &d) const
+{
+   if (size == 0)
+      return -1;
+   
+   int p = table[hashval(id)].first;
+
+   while (p != -1)
+   {
+      if (strcmp(id, table[p].data.id) == 0)
+      {
+ 	     d = table[p].data;
+	     return 0;
+      }
+      p = table[p].next;
+   }
+
+   return -1;
+}
+
+
+int hashTable::remove(const char *id)
+{
+   if (size == 0)
+      return -1;
+
+   int h = hashval(id);
+   int next = table[h].first;
+   int prev = -1;
+
+   while (next != -1)
+   {
+      if (strcmp(id, table[next].data.id) == 0)
+      {
+	 if (prev == -1)
+	    table[h].first = table[next].next;
+	 else
+	    table[prev].next = table[next].next;
+
+	 table[next].next = freepos;
+	 freepos = next;
+
+	 return 0;
+      }
+
+      prev = next;
+      next = table[next].next;
+   }
+
+   return -1;
+}
+
+
+void hashTable::clear(void)
+{
+   delete[] table;
+   freepos = -1;
+   size = 0;
+}
+
+
+void hashTable::reallocate_table(void)
+{
+   hashElement *newtable;
+   int oldsize = size;
+   int n;
+
+   if (size > 0)
+   {
+      size *= 2;
+      newtable = new hashElement[size];
+      for (int n=0 ; n<oldsize ; n++)
+	 newtable[n] = table[n];
+      delete[] table;
+      table = newtable;
+   }
+   else
+   {
+      size = 10;
+      table = new hashElement[size];
+   }
+   
+   for (n=0 ; n<oldsize ; n++)
+      table[n].first = -1;
+
+   for (n=oldsize ; n<size ; n++)
+   {
+      table[n].first = -1;
+      table[n].next = n+1;
+   }
+   table[size-1].next = -1;
+   freepos = oldsize;
+
+   for (n=0 ; n<oldsize ; n++)
+   {
+      unsigned int h = hashval(table[n].data.id);
+      table[n].next = table[h].first;
+      table[h].first = n;
+   }
+}
+
+
+unsigned int hashTable::hashval(const char *s) const
+{
+   unsigned int h = 0;
+   
+   for (const char *p=s ; *p!=0 ; p++)
+      h = (h + *p) % size;
+
+   return h;
+}
+
+
+/* EOF */