refactoring of stack-allocators

src/segmented_stack_allocator.cpp

@@ -0,0 +1,84 @@
+
+//          Copyright Oliver Kowalke 2009.
+// 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)
+
+#include <boost/coroutine/segmented_stack_allocator.hpp>
+
+#include <boost/assert.hpp>
+#include <boost/context/fcontext.hpp>
+
+#include <boost/coroutine/stack_context.hpp>
+
+// forward declaration for splitstack-functions defined in libgcc
+extern "C" {
+void *__splitstack_makecontext( std::size_t,
+                                void * [BOOST_COROUTINES_SEGMENTS],
+                                std::size_t *);
+
+void __splitstack_releasecontext( void * [BOOST_COROUTINES_SEGMENTS]);
+
+void __splitstack_resetcontext( void * [BOOST_COROUTINES_SEGMENTS]);
+
+void __splitstack_block_signals_context( void * [BOOST_COROUTINES_SEGMENTS],
+                                         int * new_value, int * old_value);
+}
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_PREFIX
+#endif
+
+#if !defined (SIGSTKSZ)
+# define SIGSTKSZ (8 * 1024)
+# define UDEF_SIGSTKSZ
+#endif
+
+namespace boost {
+namespace coroutines {
+
+bool
+segmented_stack_allocator::is_stack_unbound()
+{ return true; }
+
+std::size_t
+segmented_stack_allocator::minimum_stacksize()
+{ return SIGSTKSZ + sizeof( context::fcontext_t) + 15; }
+
+std::size_t
+segmented_stack_allocator::default_stacksize()
+{ return minimum_stacksize(); }
+
+std::size_t
+segmented_stack_allocator::maximum_stacksize()
+{
+    BOOST_ASSERT_MSG( false, "segmented stack is unbound");
+    return 0;
+}
+
+void
+segmented_stack_allocator::allocate( stack_context & ctx, std::size_t size)
+{
+    void * limit = __splitstack_makecontext( size, ctx.segments_ctx, & ctx.size);
+    BOOST_ASSERT( limit);
+    ctx.sp = static_cast< char * >( limit) + ctx.size;
+
+    int off = 0;
+     __splitstack_block_signals_context( ctx.segments_ctx, & off, 0);
+}
+
+void
+segmented_stack_allocator::deallocate( stack_context & ctx)
+{ 
+    __splitstack_releasecontext( ctx.segments_ctx);
+}
+
+}}
+
+#ifdef UDEF_SIGSTKSZ
+# undef SIGSTKSZ
+#endif
+
+#ifdef BOOST_HAS_ABI_HEADERS
+#  include BOOST_ABI_SUFFIX
+#endif