/* * Copyright (C) 2019 Apple 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 APPLE INC. ``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 APPLE INC. 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. */ #ifndef StdLibExtras_h #define StdLibExtras_h #include "BCompiler.h" #include <memory> #include <type_traits> namespace bmalloc { template<typename ToType, typename FromType> inline ToType bitwise_cast(FromType from) { static_assert(sizeof(FromType) == sizeof(ToType), "bitwise_cast size of FromType and ToType must be equal!"); #if BCOMPILER_HAS_CLANG_FEATURE(is_trivially_copyable) // Not all recent STL implementations support the std::is_trivially_copyable type trait. Work around this by only checking on toolchains which have the equivalent compiler intrinsic. static_assert(__is_trivially_copyable(ToType), "bitwise_cast of non-trivially-copyable type!"); static_assert(__is_trivially_copyable(FromType), "bitwise_cast of non-trivially-copyable type!"); #endif typename std::remove_const<ToType>::type to { }; memcpy(static_cast<void*>(&to), static_cast<void*>(&from), sizeof(to)); return to; } } // namespace bmalloc #endif // StdLibExtras_h