1 files changed, 192 insertions, 0 deletions

diff --git a/OpenSim/Region/ScriptEngine/YEngine/XMRInstQueue.cs b/OpenSim/Region/ScriptEngine/YEngine/XMRInstQueue.cs
new file mode 100644
index 0000000..549fab5
--- /dev/null
+++ b/OpenSim/Region/ScriptEngine/YEngine/XMRInstQueue.cs
@@ -0,0 +1,192 @@
+/*
+ * Copyright (c) Contributors, http://opensimulator.org/
+ * See CONTRIBUTORS.TXT for a full list of copyright holders.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *     * Redistributions of source code must retain the above copyright
+ *       notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above copyright
+ *       notice, this list of conditions and the following disclaimer in the
+ *       documentation and/or other materials provided with the distribution.
+ *     * Neither the name of the OpenSimulator Project nor the
+ *       names of its contributors may be used to endorse or promote products
+ *       derived from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+using System;
+
+namespace OpenSim.Region.ScriptEngine.Yengine
+{
+    /**
+     * @brief Implements a queue of XMRInstance's.
+     *        Do our own queue to avoid shitty little mallocs.
+     *
+     * Note: looping inst.m_NextInst and m_PrevInst back to itself
+     *       when inst is removed from a queue is purely for debug.
+     */
+    public class XMRInstQueue
+    {
+        private XMRInstance m_Head = null;
+        private XMRInstance m_Tail = null;
+
+        /**
+         * @brief Insert instance at head of queue (in front of all others)
+         * @param inst = instance to insert
+         */
+        public void InsertHead(XMRInstance inst)
+        {
+            if((inst.m_PrevInst != inst) || (inst.m_NextInst != inst))
+                throw new Exception("already in list");
+
+            inst.m_PrevInst = null;
+            if((inst.m_NextInst = m_Head) == null)
+                m_Tail = inst;
+            else
+                m_Head.m_PrevInst = inst;
+
+            m_Head = inst;
+        }
+
+        /**
+         * @brief Insert instance at tail of queue (behind all others)
+         * @param inst = instance to insert
+         */
+        public void InsertTail(XMRInstance inst)
+        {
+            if((inst.m_PrevInst != inst) || (inst.m_NextInst != inst))
+                throw new Exception("already in list");
+
+            inst.m_NextInst = null;
+            if((inst.m_PrevInst = m_Tail) == null)
+                m_Head = inst;
+            else
+                m_Tail.m_NextInst = inst;
+
+            m_Tail = inst;
+        }
+
+        /**
+         * @brief Insert instance before another element in queue
+         * @param inst  = instance to insert
+         * @param after = element that is to come after one being inserted
+         */
+        public void InsertBefore(XMRInstance inst, XMRInstance after)
+        {
+            if((inst.m_PrevInst != inst) || (inst.m_NextInst != inst))
+                throw new Exception("already in list");
+
+            if(after == null)
+                InsertTail(inst);
+            else
+            {
+                inst.m_NextInst = after;
+                inst.m_PrevInst = after.m_PrevInst;
+                if(inst.m_PrevInst == null)
+                    m_Head = inst;
+                else
+                    inst.m_PrevInst.m_NextInst = inst;
+                after.m_PrevInst = inst;
+            }
+        }
+
+        /**
+         * @brief Peek to see if anything in queue
+         * @returns first XMRInstance in queue but doesn't remove it
+         *          null if queue is empty
+         */
+        public XMRInstance PeekHead()
+        {
+            return m_Head;
+        }
+
+        /**
+         * @brief Remove first element from queue, if any
+         * @returns null if queue is empty
+         *          else returns first element in queue and removes it
+         */
+        public XMRInstance RemoveHead()
+        {
+            XMRInstance inst = m_Head;
+            if(inst != null)
+            {
+                if((m_Head = inst.m_NextInst) == null)
+                    m_Tail = null;
+                else
+                    m_Head.m_PrevInst = null;
+
+                inst.m_NextInst = inst;
+                inst.m_PrevInst = inst;
+            }
+            return inst;
+        }
+
+        /**
+         * @brief Remove last element from queue, if any
+         * @returns null if queue is empty
+         *          else returns last element in queue and removes it
+         */
+        public XMRInstance RemoveTail()
+        {
+            XMRInstance inst = m_Tail;
+            if(inst != null)
+            {
+                if((m_Tail = inst.m_PrevInst) == null)
+                    m_Head = null;
+                else
+                    m_Tail.m_NextInst = null;
+
+                inst.m_NextInst = inst;
+                inst.m_PrevInst = inst;
+            }
+            return inst;
+        }
+
+        /**
+         * @brief Remove arbitrary element from queue, if any
+         * @param inst = element to remove (assumed to be in the queue)
+         * @returns with element removed
+         */
+        public void Remove(XMRInstance inst)
+        {
+            XMRInstance next = inst.m_NextInst;
+            XMRInstance prev = inst.m_PrevInst;
+            if((prev == inst) || (next == inst))
+                throw new Exception("not in a list");
+
+            if(next == null)
+            {
+                if(m_Tail != inst)
+                    throw new Exception("not in this list");
+
+                m_Tail = prev;
+            }
+            else
+                next.m_PrevInst = prev;
+
+            if(prev == null)
+            {
+                if(m_Head != inst)
+                    throw new Exception("not in this list");
+
+                m_Head = next;
+            }
+            else
+                prev.m_NextInst = next;
+
+            inst.m_NextInst = inst;
+            inst.m_PrevInst = inst;
+        }
+    }
+}