From 154fb4317fd6ad4bd70833c914929dd91cd35745 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max.kellermann@gmail.com>
Date: Tue, 15 Nov 2022 00:23:04 +0100
Subject: [PATCH] lib/icu/CaseFold: move low-level wrapper to FoldCase.cxx

---
 src/lib/icu/CaseFold.cxx | 24 ++++-------------------
 src/lib/icu/FoldCase.cxx | 41 ++++++++++++++++++++++++++++++++++++++++
 src/lib/icu/FoldCase.hxx | 33 ++++++++++++++++++++++++++++++++
 src/lib/icu/meson.build  |  3 ++-
 4 files changed, 80 insertions(+), 21 deletions(-)
 create mode 100644 src/lib/icu/FoldCase.cxx
 create mode 100644 src/lib/icu/FoldCase.hxx

diff --git a/src/lib/icu/CaseFold.cxx b/src/lib/icu/CaseFold.cxx
index 2d9f6a24e..fd435cb06 100644
--- a/src/lib/icu/CaseFold.cxx
+++ b/src/lib/icu/CaseFold.cxx
@@ -25,41 +25,25 @@
 #include "util/AllocatedString.hxx"
 
 #ifdef HAVE_ICU
+#include "FoldCase.hxx"
 #include "Util.hxx"
 #include "util/AllocatedArray.hxx"
 #include "util/SpanCast.hxx"
-
-#include <unicode/ucol.h>
-#include <unicode/ustring.h>
-#else
-#include <algorithm>
 #endif
 
-#include <memory>
-
-#include <string.h>
-
 AllocatedString
 IcuCaseFold(std::string_view src) noexcept
 try {
 #ifdef HAVE_ICU
-	const auto u = UCharFromUTF8(src);
+	auto u = UCharFromUTF8(src);
 	if (u.data() == nullptr)
 		return {src};
 
-	AllocatedArray<UChar> folded(u.size() * 2U);
-
-	UErrorCode error_code = U_ZERO_ERROR;
-	size_t folded_length = u_strFoldCase(folded.data(), folded.size(),
-					     u.data(), u.size(),
-					     U_FOLD_CASE_DEFAULT,
-					     &error_code);
-	if (folded_length == 0 || error_code != U_ZERO_ERROR)
+	auto folded = IcuFoldCase(ToStringView(std::span{u}));
+	if (folded == nullptr)
 		return {src};
 
-	folded.SetSize(folded_length);
 	return UCharToUTF8(ToStringView(std::span{folded}));
-
 #else
 #error not implemented
 #endif
diff --git a/src/lib/icu/FoldCase.cxx b/src/lib/icu/FoldCase.cxx
new file mode 100644
index 000000000..6147ea1a3
--- /dev/null
+++ b/src/lib/icu/FoldCase.cxx
@@ -0,0 +1,41 @@
+/*
+ * Copyright 2003-2022 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#include "FoldCase.hxx"
+#include "util/AllocatedArray.hxx"
+
+#include <unicode/ucol.h>
+#include <unicode/ustring.h>
+
+AllocatedArray<UChar>
+IcuFoldCase(std::basic_string_view<UChar> src) noexcept
+{
+	AllocatedArray<UChar> dest(src.size() * 2U);
+
+	UErrorCode error_code = U_ZERO_ERROR;
+	auto length = u_strFoldCase(dest.data(), dest.size(),
+				    src.data(), src.size(),
+				    U_FOLD_CASE_DEFAULT,
+				    &error_code);
+	if (U_FAILURE(error_code))
+		return nullptr;
+
+	dest.SetSize(length);
+	return dest;
+}
diff --git a/src/lib/icu/FoldCase.hxx b/src/lib/icu/FoldCase.hxx
new file mode 100644
index 000000000..cb5c6bc84
--- /dev/null
+++ b/src/lib/icu/FoldCase.hxx
@@ -0,0 +1,33 @@
+/*
+ * Copyright 2003-2022 The Music Player Daemon Project
+ * http://www.musicpd.org
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License along
+ * with this program; if not, write to the Free Software Foundation, Inc.,
+ * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+ */
+
+#pragma once
+
+#include <unicode/umachine.h>
+
+#include <string_view>
+
+template<class T> class AllocatedArray;
+
+/**
+ * @return the normalized string (or nullptr on error)
+ */
+[[gnu::pure]]
+AllocatedArray<UChar>
+IcuFoldCase(std::basic_string_view<UChar> src) noexcept;
diff --git a/src/lib/icu/meson.build b/src/lib/icu/meson.build
index 92f9e6b1f..ff0995f8b 100644
--- a/src/lib/icu/meson.build
+++ b/src/lib/icu/meson.build
@@ -15,8 +15,9 @@ endif
 iconv_dep = []
 if icu_dep.found()
   icu_sources += [
-    'Util.cxx',
     'Init.cxx',
+    'Util.cxx',
+    'FoldCase.cxx',
   ]
 else
   if meson.version().version_compare('>= 0.60')