1 files changed, 173 insertions, 0 deletions
diff --git a/StardewInjector/CecilUtils.cs b/StardewInjector/CecilUtils.cs
new file mode 100644
index 00000000..acdf5198
--- /dev/null
+++ b/StardewInjector/CecilUtils.cs
@@ -0,0 +1,173 @@
+using Mono.Cecil;
+using Mono.Cecil.Cil;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+namespace StardewInjector
+{
+    public struct ScannerState
+    {
+        public ILProcessor ILProcessor;
+        public Instruction Instruction;
+
+        public ScannerState(ILProcessor ilProc, Instruction ins)
+        {
+            ILProcessor = ilProc;
+            Instruction = ins;
+        }
+
+        public ScannerState Previous(Func<Instruction, bool> until = null)
+        {
+            if (until != null)
+            {
+                Instruction cur = this.Instruction;
+                do
+                {
+                    cur = cur.Previous;
+                } while (!until(cur));
+                return new ScannerState(this.ILProcessor, cur);
+            }
+            return new ScannerState(this.ILProcessor, Instruction.Previous);
+        }
+
+        public ScannerState Next(Func<Instruction, bool> until = null)
+        {
+            if (until != null)
+            {
+                Instruction cur = this.Instruction;
+                do
+                {
+                    cur = cur.Next;
+                } while (!until(cur));
+                return new ScannerState(this.ILProcessor, cur);
+            }
+            return new ScannerState(this.ILProcessor, Instruction.Next);
+        }
+
+        public ScannerState Last()
+        {
+            var instructions = this.ILProcessor.Body.Instructions;
+            return new ScannerState(this.ILProcessor, instructions[instructions.Count - 1]);
+        }
+
+        public ScannerState First()
+        {
+            var instructions = this.ILProcessor.Body.Instructions;
+            return new ScannerState(this.ILProcessor, instructions[0]);
+        }
+
+        public ScannerState ReplaceCreate(OpCode opcode)
+        {
+            Instruction ins = this.ILProcessor.Create(opcode);
+            this.ILProcessor.Replace(this.Instruction, ins);
+            return new ScannerState(this.ILProcessor, ins);
+        }
+
+        public ScannerState ReplaceCreate(OpCode opcode, object arg)
+        {
+            Instruction ins = this.ILProcessor.Create(opcode, arg as dynamic);
+            this.ILProcessor.Replace(this.Instruction, ins);
+            return new ScannerState(this.ILProcessor, ins);
+        }
+
+        public ScannerState CreateBefore(OpCode opcode)
+        {
+            Instruction ins = this.ILProcessor.Create(opcode);
+            this.ILProcessor.InsertBefore(this.Instruction, ins);
+            return new ScannerState(this.ILProcessor, ins);
+        }
+
+        public ScannerState CreateBefore(OpCode opcode, object arg)
+        {
+            Instruction ins = this.ILProcessor.Create(opcode, arg as dynamic);
+            this.ILProcessor.InsertBefore(this.Instruction, ins);
+            return new ScannerState(this.ILProcessor, ins);
+        }
+
+        public ScannerState CreateAfter(OpCode opcode)
+        {
+            Instruction ins = this.ILProcessor.Create(opcode);
+            this.ILProcessor.InsertAfter(this.Instruction, ins);
+            return new ScannerState(this.ILProcessor, ins);
+        }
+
+        public ScannerState CreateAfter(OpCode opcode, object arg)
+        {
+            Instruction ins = this.ILProcessor.Create(opcode, arg as dynamic);
+            this.ILProcessor.InsertAfter(this.Instruction, ins);
+            return new ScannerState(this.ILProcessor, ins);
+        }
+    }
+
+    public static class CecilUtils
+    {
+        public static ScannerState Scanner(this MethodDefinition me)
+        {
+            return new ScannerState(me.Body.GetILProcessor(), me.Body.Instructions[0]);
+        }
+
+        public static ScannerState FindSetField(this MethodDefinition me, string fieldName)
+        {
+            var instruction = me.Body.Instructions
+                .FirstOrDefault(i => i.OpCode == OpCodes.Stsfld && (i.Operand as FieldDefinition).Name == fieldName);
+            return new ScannerState(me.Body.GetILProcessor(), instruction);
+        }
+
+        public static ScannerState FindLoadField(this MethodDefinition me, string fieldName)
+        {
+            var instruction = me.Body.Instructions
+                .FirstOrDefault(i => {
+                    if (i.OpCode != OpCodes.Ldfld && i.OpCode != OpCodes.Ldsfld)
+                        return false;
+                    if (i.Operand is FieldDefinition && (i.Operand as FieldDefinition).Name == fieldName)
+                        return true;
+                    if (i.Operand is FieldReference && (i.Operand as FieldReference).Name == fieldName)
+                        return true;
+                    return false;
+                });
+            return new ScannerState(me.Body.GetILProcessor(), instruction);
+        }
+
+        public static ScannerState FindLoadConstant(this MethodDefinition me, int val)
+        {
+            var instruction = me.Body.Instructions
+                .FirstOrDefault(i => i.OpCode == OpCodes.Ldc_I4 && (int)i.Operand == val);
+            return new ScannerState(me.Body.GetILProcessor(), instruction);
+        }
+
+        public static ScannerState FindLoadConstant(this MethodDefinition me, float val)
+        {
+            var instruction = me.Body.Instructions
+                .FirstOrDefault(i => i.OpCode == OpCodes.Ldc_R4 && (float)i.Operand == val);
+            return new ScannerState(me.Body.GetILProcessor(), instruction);
+        }
+
+        public static MethodDefinition FindMethod(this ModuleDefinition me, string name)
+        {
+            var nameSplit = name.Split(new string[] { "::" }, StringSplitOptions.RemoveEmptyEntries);
+            if (nameSplit.Length < 2)
+                throw new ArgumentException("Invalid method full name", "name");
+
+            var currentType = me.Types.FirstOrDefault(t => t.FullName == nameSplit[0]);
+            if (currentType == null)
+                return null;
+
+            return currentType.Methods.FirstOrDefault(m => m.Name == nameSplit[1]);
+        }
+
+        public static FieldDefinition FindField(this ModuleDefinition me, string name)
+        {
+            var nameSplit = name.Split(new string[] { "::" }, StringSplitOptions.RemoveEmptyEntries);
+            if (nameSplit.Length < 2)
+                throw new ArgumentException("Invalid field full name", "name");
+
+            var currentType = me.Types.FirstOrDefault(t => t.FullName == nameSplit[0]);
+            if (currentType == null)
+                return null;
+
+            return currentType.Fields.FirstOrDefault(m => m.Name == nameSplit[1]);
+        }
+    }
+}