hash: add xxhash implementation

Makefile.am

@@ -160,6 +160,8 @@ UTIL_FILES   =			\
     hash/sha2.hpp		\
     hash/wang.hpp		\
     hash/wang.ipp		\
+    hash/xxhash.cpp		\
+    hash/xxhash.hpp		\
     introspection.cpp		\
     introspection.hpp		\
     io.cpp			\
@@ -425,6 +427,7 @@ TEST_BIN = 			\
     test/hash/ripemd		\
     test/hash/sha1		\
     test/hash/sha2		\
+    test/hash/xxhash		\
     test/hton			\
     test/introspection		\
     test/json_types		\

hash/fwd.hpp

@@ -36,6 +36,8 @@ namespace util { namespace hash {
     class fletcher;
     class crc32;
 
+    class xxhash;
+
     // hash adapters
     class PBKDF1;
     class PBKDF2;

hash/xxhash.hpp

@@ -0,0 +1,63 @@
+/*
+ * 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.
+ *
+ * Copyright 2016 Danny Robson <danny@nerdcruft.net>
+ */
+
+#ifndef CRUFT_UTIL_HASH_XXHASH_HPP
+#define CRUFT_UTIL_HASH_XXHASH_HPP
+
+#include <cstdint>
+#include <type_traits>
+
+namespace util::hash {
+    template <typename T>
+    class xxhash {
+    public:
+        static_assert (std::is_same<T,uint32_t>::value || std::is_same<T,uint64_t>::value);
+        using digest_t = T;
+
+        xxhash (void);
+        xxhash (uint32_t seed);
+
+        void update (const uint8_t *restrict first, const uint8_t *restrict last);
+        void finish (void);
+        
+        digest_t digest (void) const;
+
+        void reset (void);
+
+    private:
+        uint32_t m_seed;
+
+        struct {
+            uint32_t total_len_32;
+            uint32_t large_len;
+
+            T v1, v2, v3, v4;
+            uint32_t mem32[4];
+            uint32_t memsize;
+            uint32_t reserved;
+
+            //uint64_t length;
+            //T v[4];
+            //T mem[4];
+            //unsigned memsize;
+        } m_state;
+    };
+
+    using xxhash32 = xxhash<uint32_t>;
+    using xxhash64 = xxhash<uint64_t>;
+}
+
+#endif

test/hash/xxhash.cpp

@@ -0,0 +1,58 @@
+/*
+ * 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.
+ *
+ * Copyright 2016 Danny Robson <danny@nerdcruft.net>
+ */
+
+
+#include "tap.hpp"
+
+#include "hash/simple.hpp"
+#include "hash/xxhash.hpp"
+
+int
+main (int, char **)
+{
+    util::TAP::logger tap;
+
+    static const struct {
+        uint32_t hash32;
+        uint64_t hash64;
+        unsigned seed;
+        std::string data;
+        std::string msg;
+    } TESTS[] = {
+        { 0x02CC5D05, 0xef46db3751d8e999, 0, "", "empty string, 0 seed" },
+        { 0x0b2cb792, 0xd5afba1336a3be4b, 1, "", "empty string, 1 seed" },
+        { 0x550d7456, 0xd24ec4f1a98c6e5b, 0, "a", "single a, 0 seed" },
+        { 0xf514706f, 0xdec2bc81c3cd46c6, 1, "a", "single a, 1 seed" },
+        { 0x32d153ff, 0x44bc2cf5ad770999, 0, "abc", "abc, 0 seed" },
+        { 0xaa3da8ff, 0xbea9ca8199328908, 1, "abc", "abc, 1 seed" },
+        { 0x54ca7e46, 0x892a0760a6343391, 0x1234,
+          "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789!@#$%^&*()_+",
+          "long alphabet" }
+    };
+
+    for (const auto &t: TESTS) {
+        auto first = t.data.data ();
+        auto last  = first + t.data.size ();
+
+        auto digest32 = util::hash::simple<util::hash::xxhash32> (first, last, t.seed);
+        //auto digest64 = util::hash::simple<util::hash::xxhash64> (first, last, t.seed);
+
+        tap.expect_eq (digest32, t.hash32, "xxhash32 %s", t.msg);
+        //tap.expect_eq (digest64, t.hash64, "xxhash64 %s", t.msg);
+    }
+
+    return tap.status ();
+}