ext-boost/boost/intrusive/pointer_plus_bits.hpp
Lioncash db95c7fe31 Update boost to 1.68.0
Keeps the boost libraries up to date. This also silences informational
messages that get spammed throughout the build, such as:

"Info: Boost.Config is older than your compiler version - probably
nothing bad will happen - but you may wish to look for an update Boost
version.  Define BOOST_CONFIG_SUPPRESS_OUTDATED_MESSAGE to suppress this
message."

Which makes the compilation process a lot less noisy on Windows. It's
now much easier to actually spot warnings that occur.
2018-08-21 12:23:21 -04:00

113 lines
3.7 KiB
C++

/////////////////////////////////////////////////////////////////////////////
//
// (C) Copyright Ion Gaztanaga 2007-2013
//
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
//
// See http://www.boost.org/libs/intrusive for documentation.
//
/////////////////////////////////////////////////////////////////////////////
#ifndef BOOST_INTRUSIVE_POINTER_PLUS_BITS_HPP
#define BOOST_INTRUSIVE_POINTER_PLUS_BITS_HPP
#include <boost/intrusive/detail/config_begin.hpp>
#include <boost/intrusive/intrusive_fwd.hpp>
#include <boost/intrusive/detail/mpl.hpp> //ls_zeros
#include <boost/intrusive/detail/assert.hpp> //BOOST_INTRUSIVE_INVARIANT_ASSERT
#if defined(BOOST_HAS_PRAGMA_ONCE)
# pragma once
#endif
//GCC reports uninitialized values when an uninitialized pointer plus bits type
//is asigned some bits or some pointer value, but that's ok, because we don't want
//to default initialize parts that are not being updated.
#if defined(BOOST_GCC)
# if (BOOST_GCC >= 40600)
# pragma GCC diagnostic push
# pragma GCC diagnostic ignored "-Wuninitialized"
# if (BOOST_GCC >= 40700)
# pragma GCC diagnostic ignored "-Wmaybe-uninitialized"
# endif
# endif
#endif
namespace boost {
namespace intrusive {
//!This trait class is used to know if a pointer
//!can embed extra bits of information if
//!it's going to be used to point to objects
//!with an alignment of "Alignment" bytes.
template<class VoidPointer, std::size_t Alignment>
struct max_pointer_plus_bits
{
static const std::size_t value = 0;
};
//!This is a specialization for raw pointers.
//!Raw pointers can embed extra bits in the lower bits
//!if the alignment is multiple of 2pow(NumBits).
template<std::size_t Alignment>
struct max_pointer_plus_bits<void*, Alignment>
{
static const std::size_t value = detail::ls_zeros<Alignment>::value;
};
//!This is class that is supposed to have static methods
//!to embed extra bits of information in a pointer.
//!This is a declaration and there is no default implementation,
//!because operations to embed the bits change with every pointer type.
//!
//!An implementation that detects that a pointer type whose
//!has_pointer_plus_bits<>::value is non-zero can make use of these
//!operations to embed the bits in the pointer.
template<class Pointer, std::size_t NumBits>
struct pointer_plus_bits
#ifdef BOOST_INTRUSIVE_DOXYGEN_INVOKED
{}
#endif
;
//!This is the specialization to embed extra bits of information
//!in a raw pointer. The extra bits are stored in the lower bits of the pointer.
template<class T, std::size_t NumBits>
struct pointer_plus_bits<T*, NumBits>
{
static const uintptr_t Mask = uintptr_t((uintptr_t(1u) << NumBits) - 1);
typedef T* pointer;
BOOST_INTRUSIVE_FORCEINLINE static pointer get_pointer(pointer n)
{ return pointer(uintptr_t(n) & uintptr_t(~Mask)); }
BOOST_INTRUSIVE_FORCEINLINE static void set_pointer(pointer &n, pointer p)
{
BOOST_INTRUSIVE_INVARIANT_ASSERT(0 == (uintptr_t(p) & Mask));
n = pointer(uintptr_t(p) | (uintptr_t(n) & Mask));
}
BOOST_INTRUSIVE_FORCEINLINE static std::size_t get_bits(pointer n)
{ return std::size_t(uintptr_t(n) & Mask); }
BOOST_INTRUSIVE_FORCEINLINE static void set_bits(pointer &n, std::size_t c)
{
BOOST_INTRUSIVE_INVARIANT_ASSERT(uintptr_t(c) <= Mask);
n = pointer(uintptr_t((get_pointer)(n)) | uintptr_t(c));
}
};
} //namespace intrusive
} //namespace boost
#if defined(BOOST_GCC) && (BOOST_GCC >= 40600)
# pragma GCC diagnostic pop
#endif
#include <boost/intrusive/detail/config_end.hpp>
#endif //BOOST_INTRUSIVE_POINTER_PLUS_BITS_HPP