Clean-up hash functions and introduce MurmurHash3 (twitter#145)

* remove (mostly duplicate) cc_lookup3.[ch]

* rename hash() and cc_hash.[ch] to indicate *lookup3

* bump version, introduce murmur3

CMakeLists.txt

@@ -37,7 +37,7 @@ endif()
 
 # version info
 set(${PROJECT_NAME}_VERSION_MAJOR 1)
-set(${PROJECT_NAME}_VERSION_MINOR 1)
+set(${PROJECT_NAME}_VERSION_MINOR 2)
 set(${PROJECT_NAME}_VERSION_PATCH 0)
 set(${PROJECT_NAME}_VERSION
    ${${PROJECT_NAME}_VERSION_MAJOR}.${${PROJECT_NAME}_VERSION_MINOR}.${${PROJECT_NAME}_VERSION_PATCH}

include/cc_hash.h → include/hash/cc_lookup3.h

@@ -26,7 +26,7 @@ extern "C" {
 #include <stdint.h>
 #include <stdlib.h>
 
-uint32_t hash(const void *key, size_t length, const uint32_t initval);
+uint32_t hash_lookup3(const void *key, size_t length, const uint32_t initval);
 
 #ifdef __cplusplus
 }

include/hash/cc_murmur3.h

@@ -0,0 +1,39 @@
+/*
+ * ccommon - a cache common library.
+ * Copyright (C) 2013 Twitter, Inc.
+ *
+ * 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.
+ */
+
+/**
+ * The cc_murmur3.[ch] are adapated from the canonical implementation of
+ * MurmurHash3 by Austin Appleby, released as part of SMHasher:
+ *   https://github.com/aappleby/smhasher
+ *
+ * Changes include renaming fuctions, removing MSVC-related code, adding "static"
+ * keyword to local-scope functions according to C language spec (original code is
+ * in C++), to better fit them into the scope and style of ccommon
+ *
+ * The actual implementation is untouched.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+
+void hash_murmur3_32 ( const void * key, int len, uint32_t seed, void * out );
+
+void hash_murmur3_128_x86 ( const void * key, int len, uint32_t seed, void * out );
+
+void hash_murmur3_128_x64 ( const void * key, int len, uint32_t seed, void * out );

src/hash/CMakeLists.txt

@@ -1,5 +1,5 @@
 set(SOURCE
     ${SOURCE}
-    hash/cc_hash.c
     hash/cc_lookup3.c
+    hash/cc_murmur3.c
     PARENT_SCOPE)