FTL: Support ftl::stable_hash based on CityHash64
Extends stable hash from libui by increasing maximum string length
supported from 16 to 64 bytes (CityHash64 v1.0.1 - please see
http://code.google.com/p/cityhash/).
Bug: 185536303
Bug: 194863377
Test: ftl_test
Test: Compare with 64-bit std::hash<std::string_view>
Change-Id: Ib123d0690a0d2150aa51c91526784dcf77a65d46
diff --git a/libs/ftl/Android.bp b/libs/ftl/Android.bp
index 32b2b68..4b41152 100644
--- a/libs/ftl/Android.bp
+++ b/libs/ftl/Android.bp
@@ -24,6 +24,7 @@
"flags_test.cpp",
"function_test.cpp",
"future_test.cpp",
+ "hash_test.cpp",
"match_test.cpp",
"mixins_test.cpp",
"non_null_test.cpp",
diff --git a/libs/ftl/hash_test.cpp b/libs/ftl/hash_test.cpp
new file mode 100644
index 0000000..9c7b8c2
--- /dev/null
+++ b/libs/ftl/hash_test.cpp
@@ -0,0 +1,40 @@
+/*
+ * Copyright 2024 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <ftl/hash.h>
+#include <gtest/gtest.h>
+
+#include <numeric>
+#include <string>
+
+namespace android::test {
+
+TEST(Hash, StableHash) {
+ EXPECT_EQ(11160318154034397263ull, (ftl::stable_hash({})));
+
+ std::string string(64, '?');
+ std::iota(string.begin(), string.end(), 'A');
+
+ // Maximum length is 64 characters.
+ EXPECT_FALSE(ftl::stable_hash(string + '\n'));
+
+ EXPECT_EQ(6278090252846864564ull, ftl::stable_hash(std::string_view(string).substr(0, 8)));
+ EXPECT_EQ(1883356980931444616ull, ftl::stable_hash(std::string_view(string).substr(0, 16)));
+ EXPECT_EQ(8073093283835059304ull, ftl::stable_hash(std::string_view(string).substr(0, 32)));
+ EXPECT_EQ(18197365392429149980ull, ftl::stable_hash(string));
+}
+
+} // namespace android::test