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engines/ultima/nuvie/misc/u6_list.cpp

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+/* 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 3 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, see <http://www.gnu.org/licenses/>.
+ *
+ */
+
+#include "ultima/nuvie/core/nuvie_defs.h"
+#include "ultima/nuvie/misc/u6_llist.h"
+
+namespace Ultima {
+namespace Nuvie {
+
+void retainU6Link(U6Link *link) {
+	if (link)
+		link->ref_count++;
+}
+
+void releaseU6Link(U6Link *link) {
+	if (link) {
+		link->ref_count--;
+		if (link->ref_count == 0)
+			delete link;
+	}
+}
+
+//use locally to cleanup the pointers when unlinking from list.
+inline void deleteU6Link(U6Link *link) {
+
+	if (link->ref_count == 1)
+		delete link;
+	else {
+		link->ref_count--;
+		link->data = nullptr;
+		link->prev = link->next = nullptr;
+	}
+}
+
+U6LList::U6LList() : head(nullptr), tail(nullptr) {
+}
+
+U6LList::~U6LList() {
+	removeAll();
+}
+
+bool U6LList::add(void *data) {
+	U6Link *link;
+
+	link = new U6Link;
+	if (link == nullptr)
+		return false;
+
+	if (tail == nullptr)
+		head = tail = link;
+	else {
+		link->prev = tail;
+		tail->next = link;
+		tail = link;
+	}
+
+	link->data = data;
+
+	return true;
+}
+
+bool U6LList::addAtPos(uint32 pos, void *data) {
+	uint32 i;
+	U6Link *link, *prev, *new_link;
+
+	new_link = new U6Link;
+	if (new_link == nullptr)
+		return false;
+
+	new_link->data = data;
+
+	if (pos == 0 || head == nullptr) { // pos at head or list empty
+		if (head != nullptr)
+			head->prev = new_link;
+		new_link->next = head;
+		head = new_link;
+		if (tail == nullptr)
+			tail = head;
+	} else {
+		prev = nullptr;
+		for (link = head, i = 0; link != nullptr && i < pos; i++) {
+			prev = link;
+			link = link->next;
+		}
+
+		if (prev == tail) {
+			new_link->prev = tail;
+			tail->next = new_link;
+			tail = new_link;
+		} else {
+			new_link->prev = prev;
+			new_link->next = prev->next;
+			prev->next = new_link;
+		}
+	}
+
+	return true;
+}
+
+uint32 U6LList::findPos(void *data) {
+	U6Link *link;
+	uint32 pos;
+
+	for (pos = 0, link = start(); link != nullptr; link = link->next, pos++) {
+		if (link->data == data)
+			return pos;
+	}
+
+	return 0;
+}
+
+//replace the first instance of old with new.
+bool U6LList::replace(void *old_data, void *new_data) {
+	U6Link *link;
+
+	for (link = start(); link != nullptr; link = link->next) {
+		if (link->data == old_data) {
+			link->data = new_data;
+			return true;
+		}
+	}
+
+	return false;
+}
+
+bool U6LList::remove(void *data) {
+	U6Link *link;
+	U6Link *prev;
+
+	if (head == nullptr)
+		return false;
+
+	if (head->data == data) { // remove head
+		link = head;
+		head = head->next;
+		if (head == nullptr) // empty list
+			tail = nullptr;
+		else
+			head->prev = nullptr;
+
+		deleteU6Link(link);
+
+		return true;
+	}
+
+	for (link = prev = head; link != nullptr;) {
+		if (link->data == data) {
+			prev->next = link->next;
+
+			if (link == tail)
+				tail = prev;
+
+			deleteU6Link(link);
+
+			if (link != prev && prev->next) {
+				link = prev->next;
+				link->prev = prev;
+			}
+
+			return true;
+		}
+
+		prev = link;
+		link = link->next;
+	}
+
+	return false;
+}
+
+bool U6LList::removeAll() {
+	U6Link *tmp_link, *link;
+
+	for (link = head; link != nullptr;) {
+		tmp_link = link;
+		link = link->next;
+
+		deleteU6Link(tmp_link);
+	}
+
+	head = nullptr;
+	tail = nullptr;
+
+	return true;
+}
+
+
+
+uint32 U6LList::count() const {
+	uint32 i;
+	U6Link *link;
+
+	for (i = 0, link = head; link != nullptr; link = link->next) {
+		i++;
+	}
+
+	return i;
+}
+
+U6Link *U6LList::start() {
+	return head;
+}
+
+U6Link *U6LList::end() {
+	return tail;
+}
+
+const U6Link *U6LList::start() const {
+	return head;
+}
+
+const U6Link *U6LList::end() const {
+	return tail;
+}
+
+U6Link *U6LList::gotoPos(uint32 pos) {
+	U6Link *link;
+	uint32 i;
+
+	for (link = head, i = 0; link != nullptr && i < pos; i++)
+		link = link->next;
+
+	return link;
+}
+
+} // End of namespace Nuvie
+} // End of namespace Ultima