Convert pre-increments to post-increments where possible

deob-ast/src/main/java/dev/openrs2/deob/ast/AstDeobfuscator.kt

@@ -15,6 +15,7 @@ import dev.openrs2.deob.ast.transform.BitMaskTransformer
 import dev.openrs2.deob.ast.transform.ComplementTransformer
 import dev.openrs2.deob.ast.transform.EncloseTransformer
 import dev.openrs2.deob.ast.transform.IfElseTransformer
+import dev.openrs2.deob.ast.transform.IncrementTransformer
 import dev.openrs2.deob.ast.transform.NegativeLiteralTransformer
 import dev.openrs2.deob.ast.transform.NewInstanceTransformer
 import dev.openrs2.deob.ast.transform.TernaryTransformer
@@ -87,6 +88,7 @@ class AstDeobfuscator(private val modules: List<Path>) {
             BitMaskTransformer(),
             ValueOfTransformer(),
             NewInstanceTransformer(),
+            IncrementTransformer(),
             EncloseTransformer()
         )
     }

deob-ast/src/main/java/dev/openrs2/deob/ast/transform/IncrementTransformer.kt

@@ -0,0 +1,40 @@
+package dev.openrs2.deob.ast.transform
+
+import com.github.javaparser.ast.CompilationUnit
+import com.github.javaparser.ast.Node
+import com.github.javaparser.ast.expr.UnaryExpr
+import com.github.javaparser.ast.stmt.ExpressionStmt
+import com.github.javaparser.ast.stmt.ForStmt
+import dev.openrs2.deob.ast.util.walk
+
+class IncrementTransformer : Transformer() {
+    override fun transform(unit: CompilationUnit) {
+        unit.walk(Node.TreeTraversal.POSTORDER) { stmt: ExpressionStmt ->
+            if (!stmt.expression.isUnaryExpr) {
+                return@walk
+            }
+
+            val unaryExpr = stmt.expression.asUnaryExpr()
+            unaryExpr.operator = prefixToPostfix(unaryExpr.operator)
+        }
+
+        unit.walk(Node.TreeTraversal.POSTORDER) { stmt: ForStmt ->
+            stmt.update.forEach {
+                if (!it.isUnaryExpr) {
+                    return@forEach
+                }
+
+                val unaryExpr = it.asUnaryExpr()
+                unaryExpr.operator = prefixToPostfix(unaryExpr.operator)
+            }
+        }
+    }
+
+    companion object {
+        fun prefixToPostfix(operator: UnaryExpr.Operator) = when (operator) {
+            UnaryExpr.Operator.PREFIX_INCREMENT -> UnaryExpr.Operator.POSTFIX_INCREMENT
+            UnaryExpr.Operator.PREFIX_DECREMENT -> UnaryExpr.Operator.POSTFIX_DECREMENT
+            else -> operator
+        }
+    }
+}