From 5cf87dcfdccd46f3163f623908aaefa2c9a4fa62 Mon Sep 17 00:00:00 2001
From: Shannon Booth <shannon@serenityos.org>
Date: Thu, 15 May 2025 17:56:33 +1200
Subject: [PATCH] AK: Add a Utf16View::is_code_unit_less_than helper

This seems like the natural place to put this since it is specific
to UTF-16.
---
 AK/Utf16View.cpp | 16 ++++++++++++++++
 AK/Utf16View.h   |  1 +
 2 files changed, 17 insertions(+)

diff --git a/AK/Utf16View.cpp b/AK/Utf16View.cpp
index 232dde3e063..ea2234b9ff9 100644
--- a/AK/Utf16View.cpp
+++ b/AK/Utf16View.cpp
@@ -300,6 +300,22 @@ bool Utf16View::starts_with(Utf16View const& needle) const
     return true;
 }
 
+// https://infra.spec.whatwg.org/#code-unit-less-than
+bool Utf16View::is_code_unit_less_than(Utf16View const& other) const
+{
+    auto a = m_code_units;
+    auto b = other.m_code_units;
+
+    auto common_length = min(a.size(), b.size());
+
+    for (size_t position = 0; position < common_length; ++position) {
+        if (a[position] != b[position])
+            return a[position] < b[position];
+    }
+
+    return a.size() < b.size();
+}
+
 bool Utf16View::validate() const
 {
     return simdutf::validate_utf16(char_data(), length_in_code_units());
diff --git a/AK/Utf16View.h b/AK/Utf16View.h
index 9be66ced810..26d80ee4098 100644
--- a/AK/Utf16View.h
+++ b/AK/Utf16View.h
@@ -135,6 +135,7 @@ public:
     Utf16View unicode_substring_view(size_t code_point_offset) const { return unicode_substring_view(code_point_offset, length_in_code_points() - code_point_offset); }
 
     bool starts_with(Utf16View const&) const;
+    bool is_code_unit_less_than(Utf16View const& other) const;
 
     bool validate() const;
     bool validate(size_t& valid_code_units) const;