boost/coroutine/posix/segmented_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_SEGMENTED_STACK_ALLOCATOR_H
   8 #define BOOST_COROUTINES_SEGMENTED_STACK_ALLOCATOR_H
   9
  10 #include <cstddef>
  11 #include <new>
  12
  13 #include <boost/config.hpp>
  14
  15 #include <boost/coroutine/detail/config.hpp>
  16 #include <boost/coroutine/stack_context.hpp>
  17 #include <boost/coroutine/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_COROUTINES_SEGMENTS],
  27                                 std::size_t *);
  28
  29 void __splitstack_releasecontext( void * [BOOST_COROUTINES_SEGMENTS]);
  30
  31 void __splitstack_resetcontext( void * [BOOST_COROUTINES_SEGMENTS]);
  32
  33 void __splitstack_block_signals_context( void * [BOOST_COROUTINES_SEGMENTS],
  34                                          int * new_value, int * old_value);
  35 }
  36
  37 namespace boost {
  38 namespace coroutines {
  39
  40 template< typename traitsT >
  41 struct basic_segmented_stack_allocator
  42 {
  43     typedef traitsT traits_type;
  44
  45     void allocate( stack_context & ctx, std::size_t size = traits_type::minimum_size() )
  46     {
  47         void * limit = __splitstack_makecontext( size, ctx.segments_ctx, & ctx.size);
  48         if ( ! limit) throw std::bad_alloc();
  49
  50         // ctx.size is already filled by __splitstack_makecontext
  51         ctx.sp = static_cast< char * >( limit) + ctx.size;
  52
  53         int off = 0;
  54         __splitstack_block_signals_context( ctx.segments_ctx, & off, 0);
  55     }
  56
  57     void deallocate( stack_context & ctx)
  58     { __splitstack_releasecontext( ctx.segments_ctx); }
  59 };
  60
  61 typedef basic_segmented_stack_allocator< stack_traits > segmented_stack_allocator;
  62
  63 }}
  64
  65 #ifdef BOOST_HAS_ABI_HEADERS
  66 #  include BOOST_ABI_SUFFIX
  67 #endif
  68
  69 #endif // BOOST_COROUTINES_SEGMENTED_STACK_ALLOCATOR_H