From a3a0c17ee1bdb2370b149a266b77dc6d8e2dca81 Mon Sep 17 00:00:00 2001
From: Katy Coe <djkaty@users.noreply.github.com>
Date: Tue, 30 Jun 2020 00:03:37 +0200
Subject: [PATCH] Dramatically improve startup speed when not using APK/IPA

---
 Il2CppInspector.Common/IL2CPP/Il2CppInspector.cs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/Il2CppInspector.Common/IL2CPP/Il2CppInspector.cs b/Il2CppInspector.Common/IL2CPP/Il2CppInspector.cs
index 1a4f65a..5ca1024 100644
--- a/Il2CppInspector.Common/IL2CPP/Il2CppInspector.cs
+++ b/Il2CppInspector.Common/IL2CPP/Il2CppInspector.cs
@@ -303,6 +303,12 @@ namespace Il2CppInspector
         // Returns null if package not recognized or does not contain an IL2CPP application
         public static (MemoryStream Metadata, MemoryStream Binary)? GetStreamsFromPackage(string packageFile) {
             try {
+                // Check if it's a zip file first because ZipFile.OpenRead is extremely slow if it isn't
+                using (BinaryReader zipTest = new BinaryReader(File.Open(packageFile, FileMode.Open))) {
+                    if (zipTest.ReadUInt32() != 0x04034B50)
+                        return null;
+                }
+
                 using ZipArchive zip = ZipFile.OpenRead(packageFile);
 
                 Stream metadataStream, binaryStream;