From 76e5a20e1d068b92a27bea4225ba404906256185 Mon Sep 17 00:00:00 2001
From: Alex Barney <thealexbarney@gmail.com>
Date: Sat, 10 Jul 2021 16:58:55 -0700
Subject: [PATCH] Handle old, pre-release cnmt files

---
 src/LibHac/Cnmt.cs | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/src/LibHac/Cnmt.cs b/src/LibHac/Cnmt.cs
index b5616af3..a307762f 100644
--- a/src/LibHac/Cnmt.cs
+++ b/src/LibHac/Cnmt.cs
@@ -42,7 +42,13 @@ namespace LibHac
                 TableOffset = reader.ReadUInt16();
                 ContentEntryCount = reader.ReadUInt16();
                 MetaEntryCount = reader.ReadUInt16();
-                file.Position += 12;
+
+                // Old, pre-release cnmt files don't have the "required system version" field.
+                // Try to detect this by reading the padding after that field.
+                // The old format usually contains hashes there.
+                file.Position += 8;
+                int padding = reader.ReadInt32();
+                bool isOldCnmtFormat = padding != 0;
 
                 switch (Type)
                 {
@@ -61,7 +67,8 @@ namespace LibHac
                         break;
                 }
 
-                file.Position = 0x20 + TableOffset;
+                int baseOffset = isOldCnmtFormat ? 0x18 : 0x20;
+                file.Position = baseOffset + TableOffset;
 
                 ContentEntries = new CnmtContentEntry[ContentEntryCount];
                 MetaEntries = new CnmtContentMetaEntry[MetaEntryCount];