text: // SPDX-License-Identifier: BSD-2-Clause
  //
  // Copyright (c) 2016-2018, NetApp, Inc.
  // All rights reserved.
  //
  // Redistribution and use in source and binary forms, with or without
  // modification, are permitted provided that the following conditions are met:
  //
  // 1. Redistributions of source code must retain the above copyright notice,
  //    this list of conditions and the following disclaimer.
  //
  // 2. Redistributions in binary form must reproduce the above copyright notice,
  //    this list of conditions and the following disclaimer in the documentation
  //    and/or other materials provided with the distribution.
  //
  // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  // AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  // IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  // ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
  // LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  // CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  // SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  // INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  // CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  // ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  // POSSIBILITY OF SUCH DAMAGE.
  
  #pragma once
  
  #include <stddef.h>
  #include <stdint.h>
  
  
  /// Compute an [FNV-1a 64-bit
  /// hash](http://www.isthe.com/chongo/tech/comp/fnv/index.html) over the given
  /// buffer.
  ///
  /// @param      buf       The buffer.
  /// @param      len       The length of @p buf.
  ///
  /// @return     The FNV-1a 64-bit hash of @p buffer.
  ///
  static inline uint64_t __attribute__((nonnull
  #if defined(__clang__)
                                        ,
                                        no_sanitize("unsigned-integer-overflow")
  #endif
                                            ))
  fnv1a_64(const void * const buf, const size_t len)
  {
      const uint64_t prime = 0x100000001b3;
      uint64_t hash = 0xcbf29ce484222325;
  
      const uint8_t * const bytes = (const uint8_t * const)buf;
      for (size_t i = 0; i < len; i++) {
          hash ^= bytes[i];
          hash *= prime;
      }
      return hash;
  }
  
  
  /// Compute an [FNV-1a 32-bit
  /// hash](http://www.isthe.com/chongo/tech/comp/fnv/index.html) over the given
  /// buffer.
  ///
  /// @param      buf       The buffer.
  /// @param      len       The length of @p buf.
  ///
  /// @return     The FNV-1a 32-bit hash of @p buffer.
  ///
  static inline uint32_t __attribute__((nonnull
  #if defined(__clang__)
                                        ,
                                        no_sanitize("unsigned-integer-overflow")
  #endif
                                            ))
  fnv1a_32(const void * const buf, const size_t len)
  {
      const uint32_t prime = 0x811c9dc5;
      uint32_t hash = 0x1000193;
  
      const uint8_t * const bytes = (const uint8_t * const)buf;
      for (size_t i = 0; i < len; i++) {
          hash ^= bytes[i];
          hash *= prime;
      }
      return hash;
  }
  