Merge "Exporting C++ headers from system/core" am: 812b7d5d52 am: f484dd3401

am: a252f11da3

Change-Id: If2dc2da283db7a60f478c6e61a9e9b32edb42ce7

1 files changed, 51 insertions, 0 deletions

diff --git a/libutils/include/utils/JenkinsHash.h b/libutils/include/utils/JenkinsHash.h
new file mode 100644
index 000000000..027c10c7e
--- /dev/null
+++ b/libutils/include/utils/JenkinsHash.h
@@ -0,0 +1,51 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+/* Implementation of Jenkins one-at-a-time hash function. These choices are
+ * optimized for code size and portability, rather than raw speed. But speed
+ * should still be quite good.
+ **/
+
+#ifndef ANDROID_JENKINS_HASH_H
+#define ANDROID_JENKINS_HASH_H
+
+#include <utils/TypeHelpers.h>
+
+namespace android {
+
+/* The Jenkins hash of a sequence of 32 bit words A, B, C is:
+ * Whiten(Mix(Mix(Mix(0, A), B), C)) */
+
+#ifdef __clang__
+__attribute__((no_sanitize("integer")))
+#endif
+inline uint32_t JenkinsHashMix(uint32_t hash, uint32_t data) {
+    hash += data;
+    hash += (hash << 10);
+    hash ^= (hash >> 6);
+    return hash;
+}
+
+hash_t JenkinsHashWhiten(uint32_t hash);
+
+/* Helpful utility functions for hashing data in 32 bit chunks */
+uint32_t JenkinsHashMixBytes(uint32_t hash, const uint8_t* bytes, size_t size);
+
+uint32_t JenkinsHashMixShorts(uint32_t hash, const uint16_t* shorts, size_t size);
+
+}
+
+#endif // ANDROID_JENKINS_HASH_H