From 87944997dbb274f3e2b80bbaa719b8efbe651d2a Mon Sep 17 00:00:00 2001
From: C9Glax <13404778+C9Glax@users.noreply.github.com>
Date: Sun, 5 Feb 2023 20:44:23 +0100
Subject: [PATCH] Fixed "highway" tag to key instead of value Memory usage
 decrease

---
 OSMSplitter/XMLImporter.cs | 59 +++++++++++++++++++-------------------
 1 file changed, 29 insertions(+), 30 deletions(-)

diff --git a/OSMSplitter/XMLImporter.cs b/OSMSplitter/XMLImporter.cs
index 9d6eed0..b5f6e92 100644
--- a/OSMSplitter/XMLImporter.cs
+++ b/OSMSplitter/XMLImporter.cs
@@ -50,26 +50,27 @@ namespace OSMImporter
             Dictionary<ulong, Node?> retSet = new Dictionary<ulong, Node?>();
             while (xmlReader.ReadToFollowing("way"))
             {
-                byte[] byteArray = Encoding.ASCII.GetBytes(xmlReader.ReadOuterXml());
-                MemoryStream wayStream = new MemoryStream(byteArray); 
-                XmlReader wayReader = XmlReader.Create(wayStream);
+                XmlReader wayReader = xmlReader.ReadSubtree();
                 bool addNodes = false;
-                while (wayReader.ReadToFollowing("tag") && !addNodes)
+                HashSet<string> nodeIds = new();
+                while (wayReader.Read())
                 {
-                    if (wayReader.GetAttribute("v")!.Equals("highway"))
+                    if (xmlReader.IsStartElement() && xmlReader.Name.Equals("nd"))
+                    {
+                        nodeIds.Add(wayReader.GetAttribute("ref")!);
+                    }
+                    else if (xmlReader.IsStartElement() && !addNodes && xmlReader.Name.Equals("tag") && xmlReader.GetAttribute("k")!.Equals("highway"))
                     {
                         addNodes = true;
-                        break;
                     }
                 }
+                wayReader.Close();
 
                 if (addNodes)
                 {
-                    wayStream.Position = 0;
-                    wayReader = XmlReader.Create(wayStream);
-                    while (wayReader.ReadToFollowing("nd"))
+                    foreach (string nodeId in nodeIds)
                     {
-                        retSet.TryAdd(Convert.ToUInt64(wayReader.GetAttribute("ref")!), null);
+                        retSet.TryAdd(Convert.ToUInt64(nodeId), null);
                     }
                 }
             }
@@ -99,31 +100,29 @@ namespace OSMImporter
         {
             while (xmlReader.ReadToFollowing("way"))
             {
-                byte[] byteArray = Encoding.ASCII.GetBytes(xmlReader.ReadOuterXml());
-                MemoryStream wayStream = new MemoryStream(byteArray); 
-                XmlReader wayReader = XmlReader.Create(wayStream);
-                Dictionary<string, string> tags = new Dictionary<string, string>();
-            
+                XmlReader wayReader = xmlReader.ReadSubtree();
+                HashSet<ulong> nodesInWay = new ();
+                Dictionary<string, string> tags = new ();
                 bool addNodes = false;
-                while (wayReader.ReadToFollowing("tag"))
+                while (wayReader.Read())
                 {
-                    if (wayReader.GetAttribute("v")!.Equals("highway"))
-                    {
-                        addNodes = true;
-                    }
-                    tags.Add(wayReader.GetAttribute("k")!, value: wayReader.GetAttribute("v")!);
-                }
-            
-            
-                if (addNodes)
-                {
-                    HashSet<ulong> nodesInWay = new HashSet<ulong>();
-                    wayStream.Position = 0;
-                    wayReader = XmlReader.Create(wayStream);
-                    while (wayReader.ReadToFollowing("nd"))
+                    if (wayReader.IsStartElement() && wayReader.Name.Equals("nd"))
                     {
                         nodesInWay.Add(Convert.ToUInt64(wayReader.GetAttribute("ref")));
                     }
+                    else if (wayReader.IsStartElement() && wayReader.Name.Equals("tag"))
+                    {
+                        if (wayReader.GetAttribute("k")!.Equals("highway"))
+                        {
+                            addNodes = true;
+                        }
+                        tags.Add(wayReader.GetAttribute("k")!, value: wayReader.GetAttribute("v")!);
+                    }
+                }
+                wayReader.Close();
+
+                if (addNodes)
+                {
                     ConnectNodesOfWay(nodes, nodesInWay.ToArray(), tags);
                 }
             }