ceph/src/boost/boost/json/detail/digest.hpp

   1 //
   2 // Copyright (c) 2019 Vinnie Falco (vinnie.falco@gmail.com)
   3 //
   4 // Distributed under the Boost Software License, Version 1.0. (See accompanying
   5 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
   6 //
   7 // Official repository: https://github.com/boostorg/json
   8 //
   9
  10 #ifndef BOOST_JSON_DETAIL_DIGEST_HPP
  11 #define BOOST_JSON_DETAIL_DIGEST_HPP
  12
  13 BOOST_JSON_NS_BEGIN
  14 namespace detail {
  15
  16 // Calculate salted digest of string
  17 inline
  18 std::size_t
  19 digest(
  20     char const* s,
  21     std::size_t n,
  22     std::size_t salt) noexcept
  23 {
  24 #if BOOST_JSON_ARCH == 64
  25     std::uint64_t const prime = 0x100000001B3ULL;
  26     std::uint64_t hash  = 0xcbf29ce484222325ULL;
  27 #else
  28     std::uint32_t const prime = 0x01000193UL;
  29     std::uint32_t hash  = 0x811C9DC5UL;
  30 #endif
  31     hash += salt;
  32     for(;n--;++s)
  33         hash = (*s ^ hash) * prime;
  34     return hash;
  35 }
  36
  37 } // detail
  38 BOOST_JSON_NS_END
  39
  40 #endif