SCI: Renamed int_hashmap to IntMapper, and added docs that explain that this is *not* a hashmap (at least not a plain hashmap)

svn-id: r38823

engines/sci/engine/intmap.cpp

@@ -0,0 +1,111 @@
+/* ScummVM - Graphic Adventure Engine
+ *
+ * ScummVM is the legal property of its developers, whose names
+ * are too numerous to list here. Please refer to the COPYRIGHT
+ * file distributed with this source distribution.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+ *
+ * $URL$
+ * $Id$
+ *
+ */
+
+#include "sci/engine/intmap.h"
+
+namespace Sci {
+
+#define HASH(x) (x & 0xff)
+
+IntMapper::IntMapper() {
+	base_value = 0;
+	memset(nodes, 0, sizeof(nodes));
+	holes = 0;
+}
+
+void IntMapper::free_node_recursive(Node *node) {
+	if (node) {
+		free_node_recursive(node->next);
+		node->next = 0;
+		free(node);
+	}
+}
+
+
+IntMapper::~IntMapper() {
+	int i;
+
+	for (i = 0; i < DCS_INT_HASH_MAX; i++)
+		free_node_recursive(nodes[i]);
+
+	free_node_recursive(holes);
+
+	// Trigger problems for people who forget to loose the reference
+	base_value = -42000;
+}
+
+int IntMapper::checkKey(int key, bool add, bool *was_added) {
+	Node **node = &(nodes[HASH(key)]);
+
+	while (*node && (key != (*node)->key))
+		node = &((*node)->next);
+
+	if (was_added)
+		*was_added = false;
+
+	if (*node) {
+		return (*node)->idx;
+	}
+	// Not found
+
+	if (!add)
+		return -1;
+
+	if (was_added)
+		*was_added = true;
+
+	if (holes) { // Re-use old node
+		(*node) = holes;
+		holes = (*node)->next;
+		(*node)->next = NULL;
+		(*node)->key = key;
+	} else {
+		*node = (Node*)malloc(sizeof(Node));
+		(*node)->key = key;
+		(*node)->idx = base_value++;
+		(*node)->next = NULL;
+	}
+
+	return (*node)->idx;
+}
+
+int IntMapper::removeKey(int key) {
+	Node **node = &(nodes[HASH(key)]);
+
+	while (*node && (key != (*node)->key))
+		node = &((*node)->next);
+
+	if (*node) {
+		Node *oldnode = *node;
+		*node = (*node)->next;
+
+		oldnode->next = holes; // Old node is now a 'hole'
+		holes = oldnode;
+		return oldnode->key;
+	} else
+		return -1; // Not found
+}
+
+} // End of namespace Sci