ceph/src/boost/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     }
  42
  43     stack_context allocate() {
  44         // calculate how many pages are required
  45         const std::size_t pages(
  46             static_cast< std::size_t >(
  47                 std::ceil(
  48                     static_cast< float >( size_) / traits_type::page_size() ) ) );
  49         // add one page at bottom that will be used as guard-page
  50         const std::size_t size__ = ( pages + 1) * traits_type::page_size();
  51
  52         void * vp = ::VirtualAlloc( 0, size__, MEM_COMMIT, PAGE_READWRITE);
  53         if ( ! vp) throw std::bad_alloc();
  54
  55         DWORD old_options;
  56 #if defined(BOOST_DISABLE_ASSERTS)
  57         ::VirtualProtect(
  58             vp, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
  59 #else
  60         const BOOL result = ::VirtualProtect(
  61             vp, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
  62         BOOST_ASSERT( FALSE != result);
  63 #endif
  64
  65         stack_context sctx;
  66         sctx.size = size__;
  67         sctx.sp = static_cast< char * >( vp) + sctx.size;
  68         return sctx;
  69     }
  70
  71     void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
  72         BOOST_ASSERT( sctx.sp);
  73
  74         void * vp = static_cast< char * >( sctx.sp) - sctx.size;
  75         ::VirtualFree( vp, 0, MEM_RELEASE);
  76     }
  77 };
  78
  79 typedef basic_protected_fixedsize_stack< stack_traits > protected_fixedsize_stack;
  80
  81 }}
  82
  83 #ifdef BOOST_HAS_ABI_HEADERS
  84 #  include BOOST_ABI_SUFFIX
  85 #endif
  86
  87 #endif // BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H