Merge remote-tracking branch 'origin/master'

InfectedRose.Utilities/Checksum.cs

@@ -8,29 +8,6 @@ namespace InfectedRose.Utilities
 {
     public static class Checksum
     {
-        private struct ChecksumLayer
-        {
-            internal uint Id { get; set; }
-
-            internal uint Layer { get; set; }
-
-            internal uint Revision { get; set; }
-
-            public void Apply(ref uint value, ref uint total)
-            {
-                foreach (var reference in new[] {Id, Layer, Revision})
-                {
-                    value += reference >> 16; // Apply reference
-
-                    total += value; // Add to total
-
-                    value += reference & ushort.MaxValue; // Make ushort
-
-                    total += value; // Add to total
-                }
-            }
-        }
-
         /// <summary>
         ///     Calculate the checksum for a LEGO Universe zone
         /// </summary>
@@ -126,6 +103,10 @@ public static uint Generate(string zone)
             var lower = (ushort) ((value & ushort.MaxValue) + (value >> 16));
             var upper = (ushort) ((total & ushort.MaxValue) + (total >> 16));
 
+            //
+            // The checksum has two parts, one for the 'total', and one for the 'value', these combine to form a 32bit value
+            // 
+
             return (uint) (upper << 16 | lower);
         }
 

InfectedRose.Utilities/ChecksumLayer.cs

@@ -0,0 +1,25 @@
+namespace InfectedRose.Utilities
+{
+    internal struct ChecksumLayer
+    {
+        internal uint Id { get; set; }
+
+        internal uint Layer { get; set; }
+
+        internal uint Revision { get; set; }
+
+        internal void Apply(ref uint value, ref uint total)
+        {
+            foreach (var reference in new[] {Id, Layer, Revision})
+            {
+                value += reference >> 16; // Apply reference
+
+                total += value; // Add to total
+
+                value += reference & ushort.MaxValue; // Make ushort
+
+                total += value; // Add to total
+            }
+        }
+    }
+}

InfectedRose.Utilities/Extensions/LuzFileExtensions.cs

@@ -0,0 +1,68 @@
+using System;
+using System.Collections.Generic;
+using InfectedRose.Luz;
+using InfectedRose.Lvl;
+
+namespace InfectedRose.Utilities
+{
+    public static class LuzFileExtensions
+    {
+        public static uint GenerateChecksum(this LuzFile @this, List<LvlFile> scenes)
+        {
+            if (@this.Scenes.Length != scenes.Count)
+            {
+                throw new ArgumentOutOfRangeException(nameof(scenes), "The count of scenes has to equal the count of scenes in this luz file.");
+            }
+
+            uint value = ushort.MaxValue; // For checksum calculations
+            uint total = ushort.MaxValue; // Sum of all changes applied to value
+
+            var zoneLayer = new ChecksumLayer
+            {
+                Id = uint.MaxValue,
+                Layer = default,
+                Revision = @this.RevisionNumber
+            };
+
+            zoneLayer.Apply(ref value, ref total);
+
+            for (var index = 0; index < scenes.Count; index++)
+            {
+                var scene = scenes[index];
+                var lvl = @this.Scenes[index];
+
+                //
+                // Get revision
+                //
+
+                var revision = scene.LevelInfo?.RevisionNumber ?? scene.OldLevelHeader.Revision;
+
+                //
+                // Get layer
+                //
+
+                var sceneLayer = new ChecksumLayer
+                {
+                    Id = lvl.SceneId,
+                    Layer = lvl.LayerId,
+                    Revision = revision
+                };
+
+                sceneLayer.Apply(ref value, ref total);
+            }
+
+            //
+            // Get final checksum
+            //
+
+            var lower = (ushort) ((value & ushort.MaxValue) + (value >> 16));
+            var upper = (ushort) ((total & ushort.MaxValue) + (total >> 16));
+
+            //
+            // The checksum has two parts, one for the 'total', and one for the 'value', these combine to form a 32bit value
+            // 
+
+            return (uint) (upper << 16 | lower);
+        }
+    }
+}

InfectedRose.Utilities/InfectedRose.Utilities.csproj

@@ -1,4 +1,4 @@
-<Project Sdk="Microsoft.NET.Sdk">
+<Project Sdk="Microsoft.NET.Sdk">
 
     <PropertyGroup>
         <TargetFramework>netcoreapp3.1</TargetFramework>