Squashed 'third_party/flatbuffers/' content from commit acc9990ab
Change-Id: I48550d40d78fea996ebe74e9723a5d1f910de491
git-subtree-dir: third_party/flatbuffers
git-subtree-split: acc9990abd2206491480291b0f85f925110102ea
diff --git a/include/flatbuffers/hash.h b/include/flatbuffers/hash.h
new file mode 100644
index 0000000..16536cb
--- /dev/null
+++ b/include/flatbuffers/hash.h
@@ -0,0 +1,127 @@
+/*
+ * Copyright 2015 Google Inc. All rights reserved.
+ *
+ * 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.
+ */
+
+#ifndef FLATBUFFERS_HASH_H_
+#define FLATBUFFERS_HASH_H_
+
+#include <cstdint>
+#include <cstring>
+
+#include "flatbuffers/flatbuffers.h"
+
+namespace flatbuffers {
+
+template<typename T> struct FnvTraits {
+ static const T kFnvPrime;
+ static const T kOffsetBasis;
+};
+
+template<> struct FnvTraits<uint32_t> {
+ static const uint32_t kFnvPrime = 0x01000193;
+ static const uint32_t kOffsetBasis = 0x811C9DC5;
+};
+
+template<> struct FnvTraits<uint64_t> {
+ static const uint64_t kFnvPrime = 0x00000100000001b3ULL;
+ static const uint64_t kOffsetBasis = 0xcbf29ce484222645ULL;
+};
+
+template<typename T> T HashFnv1(const char *input) {
+ T hash = FnvTraits<T>::kOffsetBasis;
+ for (const char *c = input; *c; ++c) {
+ hash *= FnvTraits<T>::kFnvPrime;
+ hash ^= static_cast<unsigned char>(*c);
+ }
+ return hash;
+}
+
+template<typename T> T HashFnv1a(const char *input) {
+ T hash = FnvTraits<T>::kOffsetBasis;
+ for (const char *c = input; *c; ++c) {
+ hash ^= static_cast<unsigned char>(*c);
+ hash *= FnvTraits<T>::kFnvPrime;
+ }
+ return hash;
+}
+
+template <> inline uint16_t HashFnv1<uint16_t>(const char *input) {
+ uint32_t hash = HashFnv1<uint32_t>(input);
+ return (hash >> 16) ^ (hash & 0xffff);
+}
+
+template <> inline uint16_t HashFnv1a<uint16_t>(const char *input) {
+ uint32_t hash = HashFnv1a<uint32_t>(input);
+ return (hash >> 16) ^ (hash & 0xffff);
+}
+
+template <typename T> struct NamedHashFunction {
+ const char *name;
+
+ typedef T (*HashFunction)(const char *);
+ HashFunction function;
+};
+
+const NamedHashFunction<uint16_t> kHashFunctions16[] = {
+ { "fnv1_16", HashFnv1<uint16_t> },
+ { "fnv1a_16", HashFnv1a<uint16_t> },
+};
+
+const NamedHashFunction<uint32_t> kHashFunctions32[] = {
+ { "fnv1_32", HashFnv1<uint32_t> },
+ { "fnv1a_32", HashFnv1a<uint32_t> },
+};
+
+const NamedHashFunction<uint64_t> kHashFunctions64[] = {
+ { "fnv1_64", HashFnv1<uint64_t> },
+ { "fnv1a_64", HashFnv1a<uint64_t> },
+};
+
+inline NamedHashFunction<uint16_t>::HashFunction FindHashFunction16(
+ const char *name) {
+ std::size_t size = sizeof(kHashFunctions16) / sizeof(kHashFunctions16[0]);
+ for (std::size_t i = 0; i < size; ++i) {
+ if (std::strcmp(name, kHashFunctions16[i].name) == 0) {
+ return kHashFunctions16[i].function;
+ }
+ }
+ return nullptr;
+}
+
+inline NamedHashFunction<uint32_t>::HashFunction FindHashFunction32(
+ const char *name) {
+ std::size_t size = sizeof(kHashFunctions32) / sizeof(kHashFunctions32[0]);
+ for (std::size_t i = 0; i < size; ++i) {
+ if (std::strcmp(name, kHashFunctions32[i].name) == 0) {
+ return kHashFunctions32[i].function;
+ }
+ }
+ return nullptr;
+}
+
+inline NamedHashFunction<uint64_t>::HashFunction FindHashFunction64(
+ const char *name) {
+ std::size_t size = sizeof(kHashFunctions64) / sizeof(kHashFunctions64[0]);
+ for (std::size_t i = 0; i < size; ++i) {
+ if (std::strcmp(name, kHashFunctions64[i].name) == 0) {
+ return kHashFunctions64[i].function;
+ }
+ }
+ return nullptr;
+}
+
+} // namespace flatbuffers
+
+#endif // FLATBUFFERS_HASH_H_