ceph/src/boost/libs/context/include/boost/context/windows/protected_fixedsize_stack.hpp

   1
   2 //          Copyright Oliver Kowalke 2014.
   3 // Distributed under the Boost Software License, Version 1.0.
   4 //    (See accompanying file LICENSE_1_0.txt or copy at
   5 //          http://www.boost.org/LICENSE_1_0.txt)
   6
   7 #ifndef BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
   8 #define BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
   9
  10 extern "C" {
  11 #include <windows.h>
  12 }
  13
  14 #include <cmath>
  15 #include <cstddef>
  16 #include <new>
  17
  18 #include <boost/config.hpp>
  19
  20 #include <boost/context/detail/config.hpp>
  21 #include <boost/context/stack_context.hpp>
  22 #include <boost/context/stack_traits.hpp>
  23
  24 #ifdef BOOST_HAS_ABI_HEADERS
  25 #  include BOOST_ABI_PREFIX
  26 #endif
  27
  28 namespace boost {
  29 namespace context {
  30
  31 template< typename traitsT >
  32 class basic_protected_fixedsize_stack {
  33 private:
  34     std::size_t     size_;
  35
  36 public:
  37     typedef traitsT traits_type;
  38
  39     basic_protected_fixedsize_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW :
  40         size_( size) {
  41         BOOST_ASSERT( traits_type::minimum_size() <= size_);
  42         BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= size_) );
  43     }
  44
  45     stack_context allocate() {
  46         // page at bottom will be used as guard-page
  47         const std::size_t pages(
  48             static_cast< std::size_t >(
  49                 std::floor(
  50                     static_cast< float >( size_) / traits_type::page_size() ) ) );
  51         BOOST_ASSERT_MSG( 2 <= pages, "at least two pages must fit into stack (one page is guard-page)");
  52         const std::size_t size__( pages * traits_type::page_size() );
  53         BOOST_ASSERT( 0 != size_ && 0 != size__);
  54         BOOST_ASSERT( size__ <= size_);
  55
  56         void * vp = ::VirtualAlloc( 0, size__, MEM_COMMIT, PAGE_READWRITE);
  57         if ( ! vp) throw std::bad_alloc();
  58
  59         DWORD old_options;
  60 #if defined(BOOST_DISABLE_ASSERTS)
  61         ::VirtualProtect(
  62             vp, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
  63 #else
  64         const BOOL result = ::VirtualProtect(
  65             vp, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
  66         BOOST_ASSERT( FALSE != result);
  67 #endif
  68
  69         stack_context sctx;
  70         sctx.size = size__;
  71         sctx.sp = static_cast< char * >( vp) + sctx.size;
  72         return sctx;
  73     }
  74
  75     void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
  76         BOOST_ASSERT( sctx.sp);
  77         BOOST_ASSERT( traits_type::minimum_size() <= sctx.size);
  78         BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= sctx.size) );
  79
  80         void * vp = static_cast< char * >( sctx.sp) - sctx.size;
  81         ::VirtualFree( vp, 0, MEM_RELEASE);
  82     }
  83 };
  84
  85 typedef basic_protected_fixedsize_stack< stack_traits > protected_fixedsize_stack;
  86
  87 }}
  88
  89 #ifdef BOOST_HAS_ABI_HEADERS
  90 #  include BOOST_ABI_SUFFIX
  91 #endif
  92
  93 #endif // BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H