ext-boost/boost/context/windows/protected_fixedsize_stack.hpp
2020-02-10 12:31:57 -04:00

88 lines
2.4 KiB
C++

// Copyright Oliver Kowalke 2014.
// Distributed under the Boost Software License, Version 1.0.
// (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
#define BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H
extern "C" {
#include <windows.h>
}
#include <cmath>
#include <cstddef>
#include <new>
#include <boost/config.hpp>
#include <boost/context/detail/config.hpp>
#include <boost/context/stack_context.hpp>
#include <boost/context/stack_traits.hpp>
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_PREFIX
#endif
namespace boost {
namespace context {
template< typename traitsT >
class basic_protected_fixedsize_stack {
private:
std::size_t size_;
public:
typedef traitsT traits_type;
basic_protected_fixedsize_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW :
size_( size) {
}
stack_context allocate() {
// calculate how many pages are required
const std::size_t pages(
static_cast< std::size_t >(
std::ceil(
static_cast< float >( size_) / traits_type::page_size() ) ) );
// add one page at bottom that will be used as guard-page
const std::size_t size__ = ( pages + 1) * traits_type::page_size();
void * vp = ::VirtualAlloc( 0, size__, MEM_COMMIT, PAGE_READWRITE);
if ( ! vp) throw std::bad_alloc();
DWORD old_options;
#if defined(BOOST_DISABLE_ASSERTS)
::VirtualProtect(
vp, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
#else
const BOOL result = ::VirtualProtect(
vp, traits_type::page_size(), PAGE_READWRITE | PAGE_GUARD /*PAGE_NOACCESS*/, & old_options);
BOOST_ASSERT( FALSE != result);
#endif
stack_context sctx;
sctx.size = size__;
sctx.sp = static_cast< char * >( vp) + sctx.size;
return sctx;
}
void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW {
BOOST_ASSERT( sctx.sp);
void * vp = static_cast< char * >( sctx.sp) - sctx.size;
::VirtualFree( vp, 0, MEM_RELEASE);
}
};
typedef basic_protected_fixedsize_stack< stack_traits > protected_fixedsize_stack;
}}
#ifdef BOOST_HAS_ABI_HEADERS
# include BOOST_ABI_SUFFIX
#endif
#endif // BOOST_CONTEXT_PROTECTED_FIXEDSIZE_H