ceph/src/boost/libs/coroutine/include/boost/coroutine/windows/protected_stack_allocator.hpp

   1
   2 //          Copyright Oliver Kowalke 2009.
   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_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
   8 #define BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_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/coroutine/detail/config.hpp>
  21 #include <boost/coroutine/stack_traits.hpp>
  22
  23 #ifdef BOOST_HAS_ABI_HEADERS
  24 #  include BOOST_ABI_PREFIX
  25 #endif
  26
  27 namespace boost {
  28 namespace coroutines {
  29
  30 struct stack_context;
  31
  32 template< typename traitsT >
  33 struct basic_protected_stack_allocator
  34 {
  35     typedef traitsT traits_type;
  36
  37     void allocate( stack_context & ctx, std::size_t size)
  38     {
  39         BOOST_ASSERT( traits_type::minimum_size() <= size);
  40         BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= size) );
  41
  42         // page at bottom will be used as guard-page
  43         const std::size_t pages(
  44             static_cast< std::size_t >(
  45                 std::floor(
  46                     static_cast< float >( size) / traits_type::page_size() ) ) );
  47         BOOST_ASSERT_MSG( 2 <= pages, "at least two pages must fit into stack (one page is guard-page)");
  48         const std::size_t size_ = pages * traits_type::page_size();
  49         BOOST_ASSERT( 0 != size && 0 != size_);
  50
  51         void * limit = ::VirtualAlloc( 0, size_, MEM_COMMIT, PAGE_READWRITE);
  52         if ( ! limit) throw std::bad_alloc();
  53
  54         DWORD old_options;
  55 #if defined(BOOST_DISABLE_ASSERTS)
  56         ::VirtualProtect(
  57             limit, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
  58 #else
  59         const BOOL result = ::VirtualProtect(
  60             limit, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
  61         BOOST_ASSERT( FALSE != result);
  62 #endif
  63
  64         ctx.size = size_;
  65         ctx.sp = static_cast< char * >( limit) + ctx.size;
  66     }
  67
  68     void deallocate( stack_context & ctx)
  69     {
  70         BOOST_ASSERT( ctx.sp);
  71         BOOST_ASSERT( traits_type::minimum_size() <= ctx.size);
  72         BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= ctx.size) );
  73
  74         void * limit = static_cast< char * >( ctx.sp) - ctx.size;
  75         ::VirtualFree( limit, 0, MEM_RELEASE);
  76     }
  77 };
  78
  79 typedef basic_protected_stack_allocator< stack_traits > protected_stack_allocator;
  80
  81 }}
  82
  83 #ifdef BOOST_HAS_ABI_HEADERS
  84 #  include BOOST_ABI_SUFFIX
  85 #endif
  86
  87 #endif // BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H