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_SEGMENTED_H 8 #define BOOST_CONTEXT_SEGMENTED_H 9 10 #include <cstddef> 11 #include <new> 12 13 #include <boost/config.hpp> 14 15 #include <boost/context/detail/config.hpp> 16 #include <boost/context/stack_context.hpp> 17 #include <boost/context/stack_traits.hpp> 18 19 #ifdef BOOST_HAS_ABI_HEADERS 20 # include BOOST_ABI_PREFIX 21 #endif 22 23 // forward declaration for splitstack-functions defined in libgcc 24 extern "C" { 25 void *__splitstack_makecontext( std::size_t, 26 void * [BOOST_CONTEXT_SEGMENTS], 27 std::size_t *); 28 29 void __splitstack_releasecontext( void * [BOOST_CONTEXT_SEGMENTS]); 30 31 void __splitstack_resetcontext( void * [BOOST_CONTEXT_SEGMENTS]); 32 33 void __splitstack_block_signals_context( void * [BOOST_CONTEXT_SEGMENTS], 34 int * new_value, int * old_value); 35 } 36 37 namespace boost { 38 namespace context { 39 40 template< typename traitsT > 41 class basic_segmented_stack { 42 private: 43 std::size_t size_; 44 45 public: 46 typedef traitsT traits_type; 47 basic_segmented_stack(std::size_t size=traits_type::default_size ())48 basic_segmented_stack( std::size_t size = traits_type::default_size() ) BOOST_NOEXCEPT_OR_NOTHROW : 49 size_( size) { 50 } 51 allocate()52 stack_context allocate() { 53 stack_context sctx; 54 void * vp = __splitstack_makecontext( size_, sctx.segments_ctx, & sctx.size); 55 if ( ! vp) throw std::bad_alloc(); 56 57 // sctx.size is already filled by __splitstack_makecontext 58 sctx.sp = static_cast< char * >( vp) + sctx.size; 59 60 int off = 0; 61 __splitstack_block_signals_context( sctx.segments_ctx, & off, 0); 62 63 return sctx; 64 } 65 deallocate(stack_context & sctx)66 void deallocate( stack_context & sctx) BOOST_NOEXCEPT_OR_NOTHROW { 67 __splitstack_releasecontext( sctx.segments_ctx); 68 } 69 }; 70 71 typedef basic_segmented_stack< stack_traits > segmented_stack; 72 # if defined(BOOST_USE_SEGMENTED_STACKS) 73 typedef segmented_stack default_stack; 74 # endif 75 76 }} 77 78 #ifdef BOOST_HAS_ABI_HEADERS 79 # include BOOST_ABI_SUFFIX 80 #endif 81 82 #endif // BOOST_CONTEXT_SEGMENTED_H 83