AK: Add a String factory to create a string from a single code point

1 files changed, 19 insertions, 0 deletions

diff --git a/AK/String.h b/AK/String.h
index dc73fe7d55..7aca7b50dc 100644
--- a/AK/String.h
+++ b/AK/String.h
@@ -1,11 +1,13 @@
 /*
  * Copyright (c) 2018-2022, Andreas Kling <kling@serenityos.org>
+ * Copyright (c) 2023, Tim Flynn <trflynn89@serenityos.org>
  *
  * SPDX-License-Identifier: BSD-2-Clause
  */
 
 #pragma once
 
+#include <AK/CharacterTypes.h>
 #include <AK/Concepts.h>
 #include <AK/Format.h>
 #include <AK/Forward.h>
@@ -16,6 +18,7 @@
 #include <AK/StringView.h>
 #include <AK/Traits.h>
 #include <AK/Types.h>
+#include <AK/UnicodeUtils.h>
 #include <AK/Vector.h>
 
 namespace AK {
@@ -74,6 +77,22 @@ public:
         return String { short_string };
     }
 
+    // Creates a new String from a single code point.
+    static constexpr String from_code_point(u32 code_point)
+    {
+        VERIFY(is_unicode(code_point));
+
+        ShortString short_string;
+        size_t i = 0;
+
+        auto length = UnicodeUtils::code_point_to_utf8(code_point, [&](auto byte) {
+            short_string.storage[i++] = static_cast<u8>(byte);
+        });
+        short_string.byte_count_and_short_string_flag = (length << 1) | SHORT_STRING_FLAG;
+
+        return String { short_string };
+    }
+
     // Creates a new String by case-transforming this String. Using these methods require linking LibUnicode into your application.
     ErrorOr<String> to_lowercase(Optional<StringView> const& locale = {}) const;
     ErrorOr<String> to_uppercase(Optional<StringView> const& locale = {}) const;