From d8c3f4e31cd5fb26d5352b578ee866e5ad18986e Mon Sep 17 00:00:00 2001
From: Desetude <harry@desetude.com>
Date: Sun, 26 Jan 2020 20:56:52 +0000
Subject: [PATCH] Flip > and >= in for loop conditions to < and <= respectively

Signed-off-by: Graham <gpe@openrs2.dev>
---
 .../dev/openrs2/deob/ast/AstDeobfuscator.kt   |  2 ++
 .../transform/ForLoopConditionTransformer.kt  | 28 +++++++++++++++++++
 2 files changed, 30 insertions(+)
 create mode 100644 deob-ast/src/main/java/dev/openrs2/deob/ast/transform/ForLoopConditionTransformer.kt

diff --git a/deob-ast/src/main/java/dev/openrs2/deob/ast/AstDeobfuscator.kt b/deob-ast/src/main/java/dev/openrs2/deob/ast/AstDeobfuscator.kt
index be62dd1b..b8d6b372 100644
--- a/deob-ast/src/main/java/dev/openrs2/deob/ast/AstDeobfuscator.kt
+++ b/deob-ast/src/main/java/dev/openrs2/deob/ast/AstDeobfuscator.kt
@@ -14,6 +14,7 @@ import dev.openrs2.deob.ast.transform.BinaryExprOrderTransformer
 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.ForLoopConditionTransformer
 import dev.openrs2.deob.ast.transform.IfElseTransformer
 import dev.openrs2.deob.ast.transform.IncrementTransformer
 import dev.openrs2.deob.ast.transform.NegativeLiteralTransformer
@@ -89,6 +90,7 @@ class AstDeobfuscator(private val modules: List<Path>) {
             ValueOfTransformer(),
             NewInstanceTransformer(),
             IncrementTransformer(),
+            ForLoopConditionTransformer(),
             EncloseTransformer()
         )
     }
diff --git a/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/ForLoopConditionTransformer.kt b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/ForLoopConditionTransformer.kt
new file mode 100644
index 00000000..51fd3338
--- /dev/null
+++ b/deob-ast/src/main/java/dev/openrs2/deob/ast/transform/ForLoopConditionTransformer.kt
@@ -0,0 +1,28 @@
+package dev.openrs2.deob.ast.transform
+
+import com.github.javaparser.ast.CompilationUnit
+import com.github.javaparser.ast.Node
+import com.github.javaparser.ast.expr.BinaryExpr
+import com.github.javaparser.ast.stmt.ForStmt
+import dev.openrs2.deob.ast.util.walk
+
+class ForLoopConditionTransformer : Transformer() {
+    override fun transform(unit: CompilationUnit) {
+        unit.walk(Node.TreeTraversal.POSTORDER) { stmt: ForStmt ->
+            stmt.compare.ifPresent { compare ->
+                if (!compare.isBinaryExpr) {
+                    return@ifPresent
+                }
+
+                val expr = compare.asBinaryExpr()
+                val flipped = when (expr.operator) {
+                    BinaryExpr.Operator.GREATER -> BinaryExpr.Operator.LESS
+                    BinaryExpr.Operator.GREATER_EQUALS -> BinaryExpr.Operator.LESS_EQUALS
+                    else -> return@ifPresent
+                }
+
+                stmt.setCompare(BinaryExpr(expr.right, expr.left, flipped))
+            }
+        }
+    }
+}