Prep for next wave of implementation

need to get a release out beforehand tho

PKHeX/Legality/RNG/RNG.cs

@@ -0,0 +1,34 @@
+namespace PKHeX.Core
+{
+    public class RNG
+    {
+        public static RNG LCRNG = new RNG(0x41C64E6D, 0x00006073, 0xEEB9EB65, 0x0A3561A1);
+        public static RNG XDRNG = new RNG(0x000343FD, 0x00269EC3, 0xB9B33155, 0xA170F641);
+        public static RNG ARNG  = new RNG(0x6C078965, 0x00000001, 0x9638806D, 0x69C77F93);
+
+        private readonly uint Mult, Add, rMult, rAdd;
+        protected RNG(uint f_mult, uint f_add, uint r_mult, uint r_add)
+        {
+            Mult = f_mult;
+            Add = f_add;
+            rMult = r_mult;
+            rAdd = r_add;
+        }
+
+        public uint Next(uint seed) => seed * Mult + Add;
+        private uint Prev(uint seed) => seed * rMult + rAdd;
+
+        private uint Advance(uint seed, int frames)
+        {
+            for (int i = 0; i < frames; i++)
+                seed = Next(seed);
+            return seed;
+        }
+        private uint Reverse(uint seed, int frames)
+        {
+            for (int i = 0; i < frames; i++)
+                seed = Prev(seed);
+            return seed;
+        }
+    }
+}

PKHeX/Legality/Structures/EncounterLock.cs

@@ -0,0 +1,10 @@
+namespace PKHeX.Core
+{
+    // Gender Locking
+    public class EncounterLock
+    {
+        public int Species;
+        public int Nature = -1;
+        public int Gender = -1;
+    }
+}

PKHeX/Legality/Structures/EncounterSlot.cs

@@ -18,7 +18,6 @@
         public bool EggEncounter => false;
         public int Generation { get; set; } = -1;
 
-        public EncounterSlot() { }
         public virtual EncounterSlot Clone()
         {
             return new EncounterSlot
@@ -47,7 +46,6 @@
     public class EncounterSlot1 : EncounterSlot
     {
         public int Rate;
-        public EncounterSlot1() { }
         public override EncounterSlot Clone()
         {
             return new EncounterSlot1

PKHeX/Legality/Structures/EncounterStatic.cs

@@ -159,4 +159,13 @@
             };
         }
     }
+
+    public class EncounterStaticShadow : EncounterStatic
+    {
+        public EncounterLock[] Locks;
+        protected override EncounterStatic Clone(int location)
+        {
+            throw new System.Exception();
+        }
+    }
 }

PKHeX/Legality/Structures/EncounterTrade.cs

@@ -5,8 +5,8 @@
         public int Species { get; set; }
         public int[] Moves { get; set; }
         public int Level;
-        public int LevelMin { get { return Level; } set { } }
-        public int LevelMax { get { return 100; } set { } }
+        public int LevelMin => Level;
+        public int LevelMax => 100;
         public int Generation { get; set; } = -1;
 
         public int Location = -1;

PKHeX/Legality/Structures/PIDIV.cs

@@ -0,0 +1,11 @@
+namespace PKHeX.Core
+{
+    public class PIDIV
+    {
+        /// <summary> The RNG that generated the PKM from the <see cref="OriginSeed"/> </summary>
+        public RNG RNG;
+
+        /// <summary> The RNG seed which immediately generates the PIDIV (starting with PID or IVs, whichever comes first). </summary>
+        public uint OriginSeed;
+    }
+}

PKHeX/PKHeX.Core.csproj

@@ -155,9 +155,11 @@
     <Compile Include="Legality\LegalityCheckStrings.cs" />
     <Compile Include="Legality\Core.cs" />
     <Compile Include="Legality\Data.cs" />
+    <Compile Include="Legality\RNG\RNG.cs" />
     <Compile Include="Legality\Structures\DexLevel.cs" />
     <Compile Include="Legality\Structures\EggMoves.cs" />
     <Compile Include="Legality\Structures\EncounterArea.cs" />
+    <Compile Include="Legality\Structures\EncounterLock.cs" />
     <Compile Include="Legality\Structures\EncounterType.cs" />
     <Compile Include="Legality\Structures\GBEncounterData.cs" />
     <Compile Include="Legality\Structures\IEncounterable.cs" />
@@ -171,6 +173,7 @@
     <Compile Include="Legality\Structures\IRibbonSet.cs" />
     <Compile Include="Legality\Structures\Learnset.cs" />
     <Compile Include="Legality\Structures\Nature.cs" />
+    <Compile Include="Legality\Structures\PIDIV.cs" />
     <Compile Include="Legality\Structures\SlotType.cs" />
     <Compile Include="Legality\Tables.cs" />
     <Compile Include="Legality\Tables2.cs" />

PKHeX/PKM/PKX.cs

@@ -60,20 +60,8 @@ namespace PKHeX.Core
             }.Contains((int)len);
         }
         
-        public static uint LCRNG(uint seed)
-        {
-            const uint a = 0x41C64E6D;
-            const uint c = 0x00006073;
-
-            return seed * a + c;
-        }
-        public static uint LCRNG(ref uint seed)
-        {
-            const uint a = 0x41C64E6D;
-            const uint c = 0x00006073;
-
-            return seed = seed * a + c;
-        }
+        public static uint LCRNG(uint seed) => RNG.LCRNG.Next(seed);
+        public static uint LCRNG(ref uint seed) => seed = RNG.LCRNG.Next(seed);
         #region ExpTable
         private static readonly uint[,] ExpTable =
         {

PKHeX/Saves/Substructures/StrategyMemo.cs

@@ -33,7 +33,7 @@ namespace PKHeX.Core
         }
         public void SetEntry(StrategyMemoEntry entry)
         {
-            int index = Array.FindIndex(Entries.ToArray(), ent => ent.Species == entry.Species);
+            int index = Entries.FindIndex(ent => ent.Species == entry.Species);
             if (index > 0)
                 Entries[index] = entry;
             else