From 4c920dfe927edfeb2340ddcca9a56424285658f4 Mon Sep 17 00:00:00 2001
From: Michael Scire <SciresM@gmail.com>
Date: Thu, 28 Jun 2018 23:24:08 -0600
Subject: [PATCH] fs.mitm: Optimize out remaining O(n^2) op. BotW is very fast.

---
 .../fs_mitm/source/fsmitm_romfsbuild.cpp         | 16 ++++++----------
 .../fs_mitm/source/fsmitm_romfsbuild.hpp         |  1 +
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/stratosphere/fs_mitm/source/fsmitm_romfsbuild.cpp b/stratosphere/fs_mitm/source/fsmitm_romfsbuild.cpp
index e493994e8..3698f57f9 100644
--- a/stratosphere/fs_mitm/source/fsmitm_romfsbuild.cpp
+++ b/stratosphere/fs_mitm/source/fsmitm_romfsbuild.cpp
@@ -273,12 +273,10 @@ void RomFSBuildContext::Build(std::vector<RomFSSourceInfo> *out_infos) {
         /* Assign deferred parent/sibling ownership. */
         if (cur_file->parent->file == NULL) {
             cur_file->parent->file = cur_file;
+            cur_file->parent->tail = cur_file;
         } else {
-            RomFSBuildFileContext *temp = cur_file->parent->file;
-            while (temp->sibling != NULL) {
-                temp = temp->sibling;
-            }
-            temp->sibling = cur_file;
+            ((RomFSBuildFileContext *)cur_file->parent->tail)->sibling = cur_file;
+            cur_file->parent->tail = cur_file;
         }
         
         prev_file = cur_file;
@@ -295,12 +293,10 @@ void RomFSBuildContext::Build(std::vector<RomFSSourceInfo> *out_infos) {
         if (cur_dir != this->root) {
             if (cur_dir->parent->child == NULL) {
                 cur_dir->parent->child = cur_dir;
+                cur_dir->parent->tail = cur_dir;
             } else {
-                RomFSBuildDirectoryContext *temp = cur_dir->parent->child;
-                while (temp->sibling != NULL) {
-                    temp = temp->sibling;
-                }
-                temp->sibling = cur_dir;
+                ((RomFSBuildDirectoryContext *)cur_dir->parent->tail)->sibling = cur_dir;
+                cur_dir->parent->tail = cur_dir;
             }
         }
     }
diff --git a/stratosphere/fs_mitm/source/fsmitm_romfsbuild.hpp b/stratosphere/fs_mitm/source/fsmitm_romfsbuild.hpp
index 004bf5426..3646e9769 100644
--- a/stratosphere/fs_mitm/source/fsmitm_romfsbuild.hpp
+++ b/stratosphere/fs_mitm/source/fsmitm_romfsbuild.hpp
@@ -153,6 +153,7 @@ struct RomFSBuildDirectoryContext {
     RomFSBuildDirectoryContext *child = NULL;
     RomFSBuildDirectoryContext *sibling = NULL;
     RomFSBuildFileContext *file = NULL;
+    void *tail;
 };
 
 struct RomFSBuildFileContext {