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Diffstat (limited to 'libtransport/src/hicn/transport/utils/hash.h')
-rwxr-xr-x | libtransport/src/hicn/transport/utils/hash.h | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/libtransport/src/hicn/transport/utils/hash.h b/libtransport/src/hicn/transport/utils/hash.h new file mode 100755 index 000000000..6815ca4bf --- /dev/null +++ b/libtransport/src/hicn/transport/utils/hash.h @@ -0,0 +1,101 @@ +/* + * Copyright (c) 2017-2019 Cisco and/or its affiliates. + * Copyright 2017 Facebook, 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. + */ + +#pragma once + +#include <hicn/transport/portability/portability.h> + +#include <cstddef> +#include <cstdint> +#include <cstring> +#include <string> +#include <tuple> +#include <type_traits> +#include <utility> + +namespace utils { + +namespace hash { + +/* + * Fowler / Noll / Vo (FNV) Hash + * http://www.isthe.com/chongo/tech/comp/fnv/ + */ + +const uint32_t FNV_32_HASH_START = 2166136261UL; +const uint64_t FNV_64_HASH_START = 14695981039346656037ULL; + +TRANSPORT_ALWAYS_INLINE uint32_t fnv32(const char *s, + uint32_t hash = FNV_32_HASH_START) { + for (; *s; ++s) { + hash += + (hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) + (hash << 24); + hash ^= *s; + } + return hash; +} + +TRANSPORT_ALWAYS_INLINE uint32_t fnv32_buf(const void *buf, size_t n, + uint32_t hash = FNV_32_HASH_START) { + // forcing signed char, since other platforms can use unsigned + const signed char *char_buf = reinterpret_cast<const signed char *>(buf); + + for (size_t i = 0; i < n; ++i) { + hash += + (hash << 1) + (hash << 4) + (hash << 7) + (hash << 8) + (hash << 24); + hash ^= char_buf[i]; + } + + return hash; +} + +TRANSPORT_ALWAYS_INLINE uint32_t fnv32(const std::string &str, + uint32_t hash = FNV_32_HASH_START) { + return fnv32_buf(str.data(), str.size(), hash); +} + +TRANSPORT_ALWAYS_INLINE uint64_t fnv64(const char *s, + uint64_t hash = FNV_64_HASH_START) { + for (; *s; ++s) { + hash += (hash << 1) + (hash << 4) + (hash << 5) + (hash << 7) + + (hash << 8) + (hash << 40); + hash ^= *s; + } + return hash; +} + +TRANSPORT_ALWAYS_INLINE uint64_t fnv64_buf(const void *buf, size_t n, + uint64_t hash = FNV_64_HASH_START) { + // forcing signed char, since other platforms can use unsigned + const signed char *char_buf = reinterpret_cast<const signed char *>(buf); + + for (size_t i = 0; i < n; ++i) { + hash += (hash << 1) + (hash << 4) + (hash << 5) + (hash << 7) + + (hash << 8) + (hash << 40); + hash ^= char_buf[i]; + } + return hash; +} + +TRANSPORT_ALWAYS_INLINE uint64_t fnv64(const std::string &str, + uint64_t hash = FNV_64_HASH_START) { + return fnv64_buf(str.data(), str.size(), hash); +} + +} // namespace hash + +} // namespace utils |