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)
7 #ifndef BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
8 #define BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H
18 #include <boost/config.hpp>
20 #include <boost/coroutine/detail/config.hpp>
21 #include <boost/coroutine/stack_traits.hpp>
23 #ifdef BOOST_HAS_ABI_HEADERS
24 # include BOOST_ABI_PREFIX
28 namespace coroutines {
32 template< typename traitsT >
33 struct basic_protected_stack_allocator
35 typedef traitsT traits_type;
37 void allocate( stack_context & ctx, std::size_t size)
39 BOOST_ASSERT( traits_type::minimum_size() <= size);
40 BOOST_ASSERT( traits_type::is_unbounded() || ( traits_type::maximum_size() >= size) );
42 // page at bottom will be used as guard-page
43 const std::size_t pages(
44 static_cast< std::size_t >(
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_);
51 void * limit = ::VirtualAlloc( 0, size_, MEM_COMMIT, PAGE_READWRITE);
52 if ( ! limit) throw std::bad_alloc();
55 #if defined(BOOST_DISABLE_ASSERTS)
57 limit, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
59 const BOOL result = ::VirtualProtect(
60 limit, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
61 BOOST_ASSERT( FALSE != result);
65 ctx.sp = static_cast< char * >( limit) + ctx.size;
68 void deallocate( stack_context & ctx)
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) );
74 void * limit = static_cast< char * >( ctx.sp) - ctx.size;
75 ::VirtualFree( limit, 0, MEM_RELEASE);
79 typedef basic_protected_stack_allocator< stack_traits > protected_stack_allocator;
83 #ifdef BOOST_HAS_ABI_HEADERS
84 # include BOOST_ABI_SUFFIX
87 #endif // BOOST_COROUTINES_PROTECTED_STACK_ALLOCATOR_H