From 2dd3b5482788b2b40ed8a7a9da04700e98e77ea9 Mon Sep 17 00:00:00 2001
From: Andreas Kling <kling@serenityos.org>
Date: Fri, 18 Feb 2022 22:56:53 +0100
Subject: [PATCH] AK: Make CaseInsensitiveStringTraits allocation-free

Instead of calling String::to_lowercase(), do case-insensitive hashing
and comparison.
---
 AK/String.h       | 4 ++--
 AK/StringImpl.cpp | 5 +++++
 AK/StringImpl.h   | 2 ++
 3 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/AK/String.h b/AK/String.h
index ceb923895b..9f7988dcdc 100644
--- a/AK/String.h
+++ b/AK/String.h
@@ -305,8 +305,8 @@ struct Traits<String> : public GenericTraits<String> {
 };
 
 struct CaseInsensitiveStringTraits : public Traits<String> {
-    static unsigned hash(const String& s) { return s.impl() ? s.to_lowercase().impl()->hash() : 0; }
-    static bool equals(const String& a, const String& b) { return a.to_lowercase() == b.to_lowercase(); }
+    static unsigned hash(String const& s) { return s.impl() ? s.impl()->case_insensitive_hash() : 0; }
+    static bool equals(String const& a, String const& b) { return a.equals_ignoring_case(b); }
 };
 
 bool operator<(const char*, const String&);
diff --git a/AK/StringImpl.cpp b/AK/StringImpl.cpp
index a7e95b847b..9ea6362d59 100644
--- a/AK/StringImpl.cpp
+++ b/AK/StringImpl.cpp
@@ -133,6 +133,11 @@ NonnullRefPtr<StringImpl> StringImpl::to_uppercase() const
     return const_cast<StringImpl&>(*this);
 }
 
+unsigned StringImpl::case_insensitive_hash() const
+{
+    return case_insensitive_string_hash(characters(), length());
+}
+
 void StringImpl::compute_hash() const
 {
     if (!length())
diff --git a/AK/StringImpl.h b/AK/StringImpl.h
index 7468924794..a06f976ab0 100644
--- a/AK/StringImpl.h
+++ b/AK/StringImpl.h
@@ -75,6 +75,8 @@ public:
         return m_hash;
     }
 
+    unsigned case_insensitive_hash() const;
+
     bool is_fly() const { return m_fly; }
     void set_fly(Badge<FlyString>, bool fly) const { m_fly = fly; }