Initial import.

hashtbl.cpp

@@ -0,0 +1,90 @@
+#include <iostream>
+#include <values.h>
+#include <malloc.h>
+#include <string.h>
+#include "hashtbl.h"
+
+HashNode::~HashNode ()
+{
+	free (key);
+	//delete (content);
+	if (next)
+		delete (next);
+}
+
+HashTable::HashTable(int n_size)
+{
+	// size = n_size;
+	// TODO allow for variable size
+	size = n_size;
+	table = (HashNode **) malloc (size * sizeof(HashNode *));
+	for (unsigned int i=0; i<size; i++)
+	{
+		table[i] = NULL;
+	}
+}
+
+HashTable::~HashTable()
+{
+	for (unsigned int i=0; i<size; i++)
+	{
+		if (table[i])
+			delete table[i];
+	}
+	free (table);
+}
+
+unsigned int HashTable::HashString (const char * str)
+{
+	unsigned int retval = 0;
+	int length = strlen(str);
+
+	unsigned int top5bits = 0xf8000000;
+	unsigned int carry = 0;
+
+	const int kleftmove=5;
+	const int krightmove=27;
+
+	for (int i=0; i<length; i++)
+	{
+		carry = retval & top5bits;
+		carry = carry >> krightmove;
+		retval = retval << kleftmove;
+		retval ^= carry;
+		retval ^= str[i];
+	}
+	return retval % size;
+}
+
+HashNode * HashTable::newHashNode(char * key, void * content, HashNode * next)
+{
+	HashNode * retval = new HashNode ();
+	retval->key = key;
+	retval->content = content;
+	retval->next = next;
+	return retval;
+}
+
+
+void HashTable::add(char * key, void * content)
+{
+	unsigned int hkey = HashString (key);
+	//cout << "Adding node: " << key << " key " << hkey << endl;
+	table[hkey] = newHashNode(key, content, table[hkey]);
+}
+
+void * HashTable::get(char * key)
+{
+	HashNode * current_node = table[HashString (key)];
+	//cout << "looking for node " << HashString (key) << endl;
+	while (current_node != NULL)
+	{
+		//cout << "found node, key = " << current_node->key << endl;
+		if (strcmp(current_node->key, key) == 0)
+		{
+			return current_node->content;
+		}
+		current_node = current_node->next;
+	}
+	return NULL;
+}