+
+\f
+////////////////////////////////////////////////////////////////////////
+// Simplified hash table for caching paths.
+////////////////////////////////////////////////////////////////////////
+
+#define HASH_TABLE_SIZE 199
+
+SGPropertyNode::hash_table::entry::entry ()
+ : _key(0),
+ _value(0)
+{
+}
+
+SGPropertyNode::hash_table::entry::~entry ()
+{
+ // Don't delete the value; we don't own
+ // the pointer.
+ delete _key;
+}
+
+void
+SGPropertyNode::hash_table::entry::set_key (const char * key)
+{
+ _key = copy_string(key);
+}
+
+void
+SGPropertyNode::hash_table::entry::set_value (SGPropertyNode * value)
+{
+ _value = value;
+}
+
+SGPropertyNode::hash_table::bucket::bucket ()
+ : _length(0),
+ _entries(0)
+{
+}
+
+SGPropertyNode::hash_table::bucket::~bucket ()
+{
+ for (int i = 0; i < _length; i++)
+ delete _entries[i];
+}
+
+SGPropertyNode::hash_table::entry *
+SGPropertyNode::hash_table::bucket::get_entry (const char * key, bool create)
+{
+ int i;
+ for (i = 0; i < _length; i++) {
+ if (!strcmp(_entries[i]->get_key(), key))
+ return _entries[i];
+ }
+ if (create) {
+ entry ** new_entries = new entry*[_length+1];
+ for (i = 0; i < _length; i++) {
+ new_entries[i] = _entries[i];
+ }
+ delete _entries;
+ _entries = new_entries;
+ _entries[_length] = new entry;
+ _entries[_length]->set_key(key);
+ _length++;
+ return _entries[_length - 1];
+ } else {
+ return 0;
+ }
+}
+
+
+SGPropertyNode::hash_table::hash_table ()
+ : _data_length(0),
+ _data(0)
+{
+}
+
+SGPropertyNode::hash_table::~hash_table ()
+{
+ for (int i = 0; i < _data_length; i++)
+ delete _data[i];
+}
+
+SGPropertyNode *
+SGPropertyNode::hash_table::get (const char * key)
+{
+ if (_data_length == 0)
+ return 0;
+ unsigned int index = hashcode(key) % _data_length;
+ if (_data[index] == 0)
+ return 0;
+ entry * e = _data[index]->get_entry(key);
+ if (e == 0)
+ return 0;
+ else
+ return e->get_value();
+}
+
+void
+SGPropertyNode::hash_table::put (const char * key, SGPropertyNode * value)
+{
+ if (_data_length == 0) {
+ _data = new bucket*[HASH_TABLE_SIZE];
+ _data_length = HASH_TABLE_SIZE;
+ for (unsigned int i = 0; i < HASH_TABLE_SIZE; i++)
+ _data[i] = 0;
+ }
+ unsigned int index = hashcode(key) % _data_length;
+ if (_data[index] == 0) {
+ _data[index] = new bucket;
+ }
+ entry * e = _data[index]->get_entry(key, true);
+ e->set_value(value);
+}
+
+unsigned int
+SGPropertyNode::hash_table::hashcode (const char * key)
+{
+ unsigned int hash = 0;
+ while (*key != 0) {
+ hash = 31 * hash + *key;
+ key++;
+ }
+ return hash;
+}
+