From 78fcbed6f2976992967e55963639e1278291d68a Mon Sep 17 00:00:00 2001
From: Fabian Homborg <FHomborg@gmail.com>
Date: Thu, 30 Sep 2021 17:47:08 +0200
Subject: [PATCH] wcsfilecmp: Skip towlower/upper if unnecessary

Also for the glob version, because this is just a performance thing.

Makes `echo **` 20% faster - 100ms to 80ms for the fish repo.

This also applies to the future `path` builtin.

Still not a speed demon, but this is a very very easy win.

Now we probably gotta do globbing all in string instead of wcs2stringing ourselves to death.
---
 src/util.cpp | 14 ++++++++++++++
 1 file changed, 14 insertions(+)

diff --git a/src/util.cpp b/src/util.cpp
index b2fb04299..969266b4a 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -62,6 +62,13 @@ int wcsfilecmp(const wchar_t *a, const wchar_t *b) {
             if (retval || *a == 0 || *b == 0) break;
         }
 
+        // Fast path: Skip towupper.
+        if (*a == *b) {
+            a++;
+            b++;
+            continue;
+        }
+
         wint_t al = towupper(*a);
         wint_t bl = towupper(*b);
         // Sort dashes after Z - see #5634
@@ -115,6 +122,13 @@ int wcsfilecmp_glob(const wchar_t *a, const wchar_t *b) {
             if (retval || *a == 0 || *b == 0) break;
         }
 
+        // Fast path: Skip towlower.
+        if (*a == *b) {
+            a++;
+            b++;
+            continue;
+        }
+
         wint_t al = towlower(*a);
         wint_t bl = towlower(*b);
         if (al < bl) {