Syroot.Worms.Armageddon 4.0.1: Optimize WA v3 schemes to store only non-default extended options.

- Adds SchemeVersionExtensions.GetWeaponCount(), returning how many weapons are stored by the corresponding SchemeVersion.
- Adds ExtendedOptions.AsSpan() to return the unmanaged representation of the extended settings.
- Optimize usage of .NET Standard 2.0 Span backports.

src/library/Syroot.Worms.Armageddon/Scheme.Enums.cs

@@ -72,6 +72,21 @@ namespace Syroot.Worms.Armageddon
         Version3 = 3
     }
 
+    /// <summary>
+    /// Represents extension methods for <see cref="SchemeVersion"/> instances.
+    /// </summary>
+    public static class SchemeVersionExtensions
+    {
+        // ---- METHODS (PUBLIC) ---------------------------------------------------------------------------------------
+
+        /// <summary>
+        /// Returns how many <see cref="SchemeWeapon"/> instances are stored in the <paramref name="version"/>.
+        /// </summary>
+        /// <param name="version">The <see cref="SchemeVersion"/>.</param>
+        /// <returns>The number of weapons stored for this version.</returns>
+        public static int GetWeaponCount(this SchemeVersion version) => version == SchemeVersion.Version1 ? 45 : 64;
+    }
+
     /// <summary>
     /// Represents the gravity simulation used in a game (as originating from RubberWorm).
     /// </summary>

src/library/Syroot.Worms.Armageddon/Scheme.ExtendedOptions.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Runtime.CompilerServices;
 using System.Runtime.InteropServices;
 
 namespace Syroot.Worms.Armageddon
@@ -1102,7 +1103,14 @@ namespace Syroot.Worms.Armageddon
                 return hash.ToHashCode();
             }
 
-            private float FixedPointToSingle(int value) => value / 65536f;
+            /// <summary>
+            /// Returns this instance as raw data.
+            /// </summary>
+            /// <returns>A <see cref="Span{Byte}"/> storing the raw data of the options.</returns>
+            internal unsafe Span<byte> AsSpan()
+                => new Span<byte>(Unsafe.AsPointer(ref this), Unsafe.SizeOf<ExtendedOptions>());
+
+            private static float FixedPointToSingle(int value) => value / 65536f;
 
             private static byte NullBoolToTriState(bool? value) => value switch
             {
@@ -1117,7 +1125,7 @@ namespace Syroot.Worms.Armageddon
                 _ => value.Value
             };
 
-            private int SingleToFixedPoint(float value) => (int)(value * 65536);
+            private static int SingleToFixedPoint(float value) => (int)(value * 65536);
 
             private static bool? TriStateToNullBool(byte value) => value switch
             {

src/library/Syroot.Worms.Armageddon/Scheme.cs

@@ -3,7 +3,6 @@ using System.Buffers.Binary;
 using System.Collections.Generic;
 using System.IO;
 using System.Linq;
-using System.Runtime.CompilerServices;
 using System.Text;
 using Syroot.BinaryData;
 using Syroot.Worms.Core;
@@ -1067,7 +1066,7 @@ namespace Syroot.Worms.Armageddon
 
             // Read the weapons.
             Weapons = new WeaponList();
-            reader.ReadStructs(Weapons.AsSpan(GetWeaponCount(Version)));
+            reader.ReadStructs(Weapons.AsSpan(Version.GetWeaponCount()));
 
             // Read available extended settings or deserialize them from RubberWorm settings encoded in probabilities.
             switch (Version)
@@ -1201,13 +1200,13 @@ namespace Syroot.Worms.Armageddon
                 SaveRubberWorm();
 
             // Write the weapons.
-            writer.WriteStructs<SchemeWeapon>(Weapons.AsSpan(GetWeaponCount(version)));
+            writer.WriteStructs<SchemeWeapon>(Weapons.AsSpan(version.GetWeaponCount()));
 
             // Clear RubberWorm probabilities again or write available extended settings.
             switch (version)
             {
                 case SchemeVersion.Version2: ClearRubberWorm(); break;
-                case SchemeVersion.Version3: SaveExtendedOptions(writer); break;
+                case SchemeVersion.Version3: SaveExtendedOptions(writer, Attachment.Length == 0); break;
             }
 
             // Write any trailing bytes (either unknown extended scheme options or unknown WWP trash).
@@ -1216,8 +1215,6 @@ namespace Syroot.Worms.Armageddon
 
         // ---- METHODS (PRIVATE) --------------------------------------------------------------------------------------
 
-        private static int GetWeaponCount(SchemeVersion version) => version == SchemeVersion.Version1 ? 45 : 64;
-
         private void ClearRubberWorm()
         {
             // Reset all super weapon probabilities to remove any settings made by RubberWorm.
@@ -1229,23 +1226,10 @@ namespace Syroot.Worms.Armageddon
 
         private unsafe void LoadExtendedOptions(BinaryStream reader)
         {
-            if (reader.EndOfStream)
+            // Create a copy of default options overwritten by available extended data.
-            {
+            Span<byte> bytes = _extended.AsSpan();
-                ClearExtendedOptions();
+            ExtendedOptions.Default.AsSpan().CopyTo(bytes);
-            }
-            else
-            {
-                Span<byte> bytes = new Span<byte>(
-                    Unsafe.AsPointer(ref _extended), Unsafe.SizeOf<ExtendedOptions>());
-#if NETSTANDARD2_0
-                // Cannot prevent copy in .NET Standard 2.0.
-                byte[] buffer = new byte[(int)Math.Min(bytes.Length, reader.Length - reader.Position)];
-                reader.Read(buffer, 0, buffer.Length);
-                buffer.AsSpan().CopyTo(bytes);
-#else
             reader.Read(bytes);
-#endif
-            }
         }
 
         private void LoadRubberWorm()
@@ -1362,16 +1346,19 @@ namespace Syroot.Worms.Armageddon
             ClearRubberWorm();
         }
 
-        private unsafe void SaveExtendedOptions(BinaryStream writer)
+        private unsafe void SaveExtendedOptions(BinaryStream writer, bool trim)
         {
-            ReadOnlySpan<byte> bytes = new ReadOnlySpan<byte>(
+            ReadOnlySpan<byte> bytes = _extended.AsSpan();
-                Unsafe.AsPointer(ref _extended), Unsafe.SizeOf<ExtendedOptions>());
+
-#if NETSTANDARD2_0
+            // Trim away default bytes.
-            // Cannot prevent copy in .NET Standard 2.0.
+            int length = bytes.Length;
-            writer.Write(bytes.ToArray());
+            if (trim)
-#else
+            {
-            writer.Write(bytes);
+                ReadOnlySpan<byte> defaultBytes = ExtendedOptions.Default.AsSpan();
-#endif
+                for (; length > 0 && bytes[length - 1] == defaultBytes[length - 1]; length--) ;
+            }
+
+            writer.Write(bytes.Slice(0, length));
         }
 
         private void SaveRubberWorm()

src/library/Syroot.Worms.Armageddon/Syroot.Worms.Armageddon.csproj

@@ -7,7 +7,7 @@
     <Description>.NET library for loading and modifying files of Team17's Worms Armageddon.</Description>
     <PackageReleaseNotes>Overhaul implementation and documentation. Implement W:A V3 scheme format.</PackageReleaseNotes>
     <PackageTags>$(PackageTags);worms armageddon</PackageTags>
-    <Version>4.0.0</Version>
+    <Version>4.0.1</Version>
   </PropertyGroup>
   
   <!-- References -->

src/library/Syroot.Worms/IO/StreamExtensions.cs

@@ -84,8 +84,8 @@ namespace Syroot.Worms.IO
         /// <param name="value">The instance to write into the current stream.</param>
         public static void Save<T>(this Stream stream, T value) where T : ISaveable => value.Save(stream);
 
-        // ---- Backports ----
 #if NETSTANDARD2_0
+        // ---- Backports ----
 
         /// <summary>
         /// When overridden in a derived class, reads a sequence of bytes from the current stream and advances the

src/test/Syroot.Worms.Armageddon.Test/SchemeTests.cs

@@ -19,13 +19,13 @@ namespace Syroot.Worms.Test.Armageddon
         /// Tests all files found in the test directory.
         /// </summary>
         [TestMethod]
-        public void TestFiles() => Tools.TestFiles<Scheme>("*.wsc");
+        public void TestSchemes() => Tools.TestFiles<Scheme>("*.wsc");
 
         /// <summary>
         /// Tests all schemes from a Worms Scheme Database CSV dump (ask owner Byte for updated dumps).
         /// </summary>
         [TestMethod]
-        public void TestWsdb()
+        public void TestSchemesWsdb()
         {
             // Reuse buffer for all schemes, including the SCHM header stripped in the dump.
             byte[] buffer = new byte[407];