ceph/src/boost/boost/uuid/detail/random_provider.hpp

   1 //
   2 // Copyright (c) 2017 James E. King III
   3 //
   4 // Distributed under the Boost Software License, Version 1.0.
   5 // (See accompanying file LICENSE_1_0.txt or copy at
   6 //   https://www.boost.org/LICENSE_1_0.txt)
   7 //
   8 // Platform-specific random entropy provider
   9 //
  10
  11 #ifndef BOOST_UUID_DETAIL_RANDOM_PROVIDER_HPP
  12 #define BOOST_UUID_DETAIL_RANDOM_PROVIDER_HPP
  13
  14 #include <boost/config.hpp>
  15 #include <boost/cstdint.hpp>
  16 #include <boost/limits.hpp>
  17 #include <boost/static_assert.hpp>
  18 #include <boost/move/core.hpp>
  19 #include <boost/move/utility_core.hpp>
  20 #include <boost/type_traits/is_integral.hpp>
  21 #include <boost/type_traits/is_unsigned.hpp>
  22 #include <boost/uuid/entropy_error.hpp>
  23 #include <climits>
  24 #include <iterator>
  25
  26 // Detection of the platform is separated from inclusion of the correct
  27 // header to facilitate mock testing of the provider implementations.
  28
  29 #include <boost/uuid/detail/random_provider_detect_platform.hpp>
  30 #include <boost/uuid/detail/random_provider_include_platform.hpp>
  31
  32
  33 namespace boost {
  34 namespace uuids {
  35 namespace detail {
  36
  37 //! \brief Contains code common to all random_provider implementations.
  38 //! \note  random_provider_base is required to provide this method:
  39 //!        void get_random_bytes(void *buf, size_t siz);
  40 //! \note  noncopyable because of some base implementations so
  41 //!        this makes it uniform across platforms to avoid any
  42 //!        porting surprises
  43 class random_provider :
  44     public detail::random_provider_base
  45 {
  46     BOOST_MOVABLE_BUT_NOT_COPYABLE(random_provider)
  47
  48 public:
  49     BOOST_DEFAULTED_FUNCTION(random_provider(), {})
  50
  51     random_provider(BOOST_RV_REF(random_provider) that) BOOST_NOEXCEPT :
  52         detail::random_provider_base(boost::move(static_cast< detail::random_provider_base& >(that)))
  53     {
  54     }
  55
  56     random_provider& operator= (BOOST_RV_REF(random_provider) that) BOOST_NOEXCEPT
  57     {
  58         static_cast< detail::random_provider_base& >(*this) = boost::move(static_cast< detail::random_provider_base& >(that));
  59         return *this;
  60     }
  61
  62     //! Leverage the provider as a SeedSeq for
  63     //! PseudoRandomNumberGeneration seeing.
  64     //! \note: See Boost.Random documentation for more details
  65     template<class Iter>
  66     void generate(Iter first, Iter last)
  67     {
  68         typedef typename std::iterator_traits<Iter>::value_type value_type;
  69         BOOST_STATIC_ASSERT(is_integral<value_type>::value);
  70         BOOST_STATIC_ASSERT(is_unsigned<value_type>::value);
  71         BOOST_STATIC_ASSERT(sizeof(value_type) * CHAR_BIT >= 32);
  72
  73         for (; first != last; ++first)
  74         {
  75             get_random_bytes(&*first, sizeof(*first));
  76             *first &= (std::numeric_limits<boost::uint32_t>::max)();
  77         }
  78     }
  79
  80     //! Return the name of the selected provider
  81     const char * name() const
  82     {
  83         return BOOST_UUID_RANDOM_PROVIDER_STRINGIFY(BOOST_UUID_RANDOM_PROVIDER_NAME);
  84     }
  85 };
  86
  87 } // detail
  88 } // uuids
  89 } // boost
  90
  91 #endif // BOOST_UUID_DETAIL_RANDOM_PROVIDER_HPP