From abcb2d42bc34ef143c0498bb63508377815a0206 Mon Sep 17 00:00:00 2001
From: Timothy Flynn <trflynn89@pm.me>
Date: Wed, 23 Jul 2025 15:25:14 -0400
Subject: [PATCH] LibUnicode: Port Intl.PluralRules to UTF-16 strings

---
 Libraries/LibUnicode/ICU.cpp          | 5 +++++
 Libraries/LibUnicode/ICU.h            | 2 ++
 Libraries/LibUnicode/NumberFormat.cpp | 6 +++---
 Libraries/LibUnicode/PluralRules.cpp  | 6 +++---
 Libraries/LibUnicode/PluralRules.h    | 7 ++++---
 5 files changed, 17 insertions(+), 9 deletions(-)

diff --git a/Libraries/LibUnicode/ICU.cpp b/Libraries/LibUnicode/ICU.cpp
index 9359673c7b7..2dd1f8cc948 100644
--- a/Libraries/LibUnicode/ICU.cpp
+++ b/Libraries/LibUnicode/ICU.cpp
@@ -169,6 +169,11 @@ Utf16String icu_string_to_utf16_string(UChar const* string, i32 length)
     return Utf16String::from_utf16_without_validation({ string, static_cast<size_t>(length) });
 }
 
+Utf16View icu_string_to_utf16_view(icu::UnicodeString const& string)
+{
+    return { string.getBuffer(), static_cast<size_t>(string.length()) };
+}
+
 UCharIterator icu_string_iterator(Utf16View const& string)
 {
     UCharIterator iterator;
diff --git a/Libraries/LibUnicode/ICU.h b/Libraries/LibUnicode/ICU.h
index 8392e29a616..c2ad5f3747b 100644
--- a/Libraries/LibUnicode/ICU.h
+++ b/Libraries/LibUnicode/ICU.h
@@ -116,6 +116,8 @@ String icu_string_to_string(UChar const*, i32 length);
 Utf16String icu_string_to_utf16_string(icu::UnicodeString const& string);
 Utf16String icu_string_to_utf16_string(UChar const*, i32 length);
 
+Utf16View icu_string_to_utf16_view(icu::UnicodeString const& string);
+
 UCharIterator icu_string_iterator(Utf16View const&);
 
 template<typename Filter>
diff --git a/Libraries/LibUnicode/NumberFormat.cpp b/Libraries/LibUnicode/NumberFormat.cpp
index 35a79a7de60..e214e65f476 100644
--- a/Libraries/LibUnicode/NumberFormat.cpp
+++ b/Libraries/LibUnicode/NumberFormat.cpp
@@ -671,7 +671,7 @@ public:
         if (icu_failure(status))
             return PluralCategory::Other;
 
-        return plural_category_from_string(icu_string_to_string(result));
+        return plural_category_from_string(icu_string_to_utf16_view(result));
     }
 
     virtual PluralCategory select_plural_range(double start, double end) const override
@@ -694,7 +694,7 @@ public:
         if (icu_failure(status))
             return PluralCategory::Other;
 
-        return plural_category_from_string(icu_string_to_string(result));
+        return plural_category_from_string(icu_string_to_utf16_view(result));
     }
 
     virtual Vector<PluralCategory> available_plural_categories() const override
@@ -710,7 +710,7 @@ public:
 
         while (true) {
             i32 length = 0;
-            auto const* category = keywords->next(&length, status);
+            auto const* category = keywords->unext(&length, status);
 
             if (icu_failure(status) || category == nullptr)
                 break;
diff --git a/Libraries/LibUnicode/PluralRules.cpp b/Libraries/LibUnicode/PluralRules.cpp
index 5773d474be5..e229aa06a70 100644
--- a/Libraries/LibUnicode/PluralRules.cpp
+++ b/Libraries/LibUnicode/PluralRules.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2024, Tim Flynn <trflynn89@serenityos.org>
+ * Copyright (c) 2022-2025, Tim Flynn <trflynn89@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -28,7 +28,7 @@ StringView plural_form_to_string(PluralForm plural_form)
     VERIFY_NOT_REACHED();
 }
 
-PluralCategory plural_category_from_string(StringView category)
+PluralCategory plural_category_from_string(Utf16View const& category)
 {
     if (category == "other"sv)
         return PluralCategory::Other;
@@ -49,7 +49,7 @@ PluralCategory plural_category_from_string(StringView category)
     VERIFY_NOT_REACHED();
 }
 
-StringView plural_category_to_string(PluralCategory category)
+Utf16View plural_category_to_string(PluralCategory category)
 {
     switch (category) {
     case PluralCategory::Other:
diff --git a/Libraries/LibUnicode/PluralRules.h b/Libraries/LibUnicode/PluralRules.h
index 62182bd0d90..7b3a21eb1b0 100644
--- a/Libraries/LibUnicode/PluralRules.h
+++ b/Libraries/LibUnicode/PluralRules.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2022-2024, Tim Flynn <trflynn89@ladybird.org>
+ * Copyright (c) 2022-2025, Tim Flynn <trflynn89@ladybird.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
@@ -7,6 +7,7 @@
 #pragma once
 
 #include <AK/StringView.h>
+#include <AK/Utf16View.h>
 
 namespace Unicode {
 
@@ -30,7 +31,7 @@ enum class PluralCategory {
     ExactlyZero,
     ExactlyOne,
 };
-PluralCategory plural_category_from_string(StringView);
-StringView plural_category_to_string(PluralCategory);
+PluralCategory plural_category_from_string(Utf16View const&);
+Utf16View plural_category_to_string(PluralCategory);
 
 }