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VARIANT_MINIMIZE_SIZE introduction plus various cleanup.

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[SVN r19163]
This commit is contained in:
Eric Friedman
2003-07-17 00:53:32 +00:00
parent 6a510db892
commit eea0ca8875
1 changed files with 74 additions and 33 deletions
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107
include/boost/variant/variant.hpp
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@@ -30,6 +30,7 @@
#include "boost/config.hpp"
#include "boost/detail/workaround.hpp"
#include "boost/mpl/aux_/config/eti.hpp"
#include "boost/mpl/aux_/deref_wknd.hpp"
#include "boost/mpl/aux_/value_wknd.hpp"
#include "boost/aligned_storage.hpp"
@@ -54,7 +55,6 @@
#include "boost/mpl/contains.hpp"
#include "boost/mpl/count_if.hpp"
#include "boost/mpl/distance.hpp"
#include "boost/mpl/deref.hpp"
#include "boost/mpl/empty.hpp"
#include "boost/mpl/equal_to.hpp"
#include "boost/mpl/identity.hpp"
@@ -74,6 +74,21 @@
#include "boost/mpl/void.hpp"
//////////////////////////////////////////////////////////////////////////
// BOOST_VARIANT_MINIMIZE_SIZE
//
// When #defined, implementation employs all known means to minimize the
// size of variant objects. However, often unsuccessful due to alignment
// issues, and potentially harmful to runtime speed, so not enabled by
// default. (TODO: Investigate further.)
//
#if defined(BOOST_VARIANT_MINIMIZE_SIZE)
# include <climits> // for SCHAR_MAX
# include "boost/mpl/less.hpp"
# include "boost/mpl/long.hpp"
# include "boost/mpl/O1_size.hpp"
#endif
//////////////////////////////////////////////////////////////////////////
// BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT
//
@@ -103,7 +118,7 @@ private: // helpers, for metafunction result (below)
public: // metafunction result
typedef typename mpl::deref<max_it>::type
typedef typename BOOST_MPL_AUX_DEREF_WNKD(max_it)
type;
};
@@ -520,30 +535,7 @@ private:
#endif // borland workaround
private: // static precondition assertions
#if defined(BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT)
// Sequences are not supported for compilers that do not support
// using declarations in templates (see below).
#if !BOOST_WORKAROUND(BOOST_MSVC, <= 1200)
BOOST_STATIC_ASSERT((
BOOST_MPL_AUX_VALUE_WKND(
mpl::not_< mpl::is_sequence<T0> >
)::value
));
#else
BOOST_STATIC_CONSTANT(bool, not_is_sequence_T0 = mpl::not_< mpl::is_sequence<T0> >::value);
BOOST_STATIC_ASSERT(not_is_sequence_T0);
#endif
#endif // BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT
#if !defined(BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT)
public: // typedefs
@@ -555,6 +547,34 @@ public: // typedefs
>
>::type types;
#else // defined(BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT)
public: // typedefs
typedef typename detail::variant::make_variant_list<
BOOST_VARIANT_ENUM_PARAMS(T)
>::type types;
private: // static precondition assertions
// Sequences are not supported for compilers that do not support
// using declarations in templates (see below).
# if !BOOST_WORKAROUND(BOOST_MSVC, <= 1200)
BOOST_STATIC_ASSERT((
::boost::mpl::not_< mpl::is_sequence<T0> >::value
));
# else // MSVC6
BOOST_STATIC_CONSTANT(bool, msvc_not_is_sequence_T0 = mpl::not_< mpl::is_sequence<T0> >::value);
BOOST_STATIC_ASSERT(msvc_not_is_sequence_T0);
# endif // MSVC6 workaround
#endif // BOOST_VARIANT_NO_TYPE_SEQUENCE_SUPPORT
private: // static precondition assertions, cont.
// [Assert unique types: ommitted due to compile-time complexity.]
@@ -607,7 +627,28 @@ private: // representation (int which_)
// if which_ >= 0:
// * then which() -> which_
// * else which() -> -(which_ + 1)
int which_;
#if !defined(BOOST_VARIANT_MINIMIZE_SIZE)
typedef int which_t;
#else // defined(BOOST_VARIANT_MINIMIZE_SIZE)
// [if O1_size available, then attempt which_t size optimization...]
// [select signed char if fewer than SCHAR_MAX types, else signed int:]
typedef typename mpl::apply_if<
mpl::equal_to< mpl::O1_size<types>, mpl::long_<-1> >
, mpl::identity< int >
, mpl::if_<
mpl::less< mpl::O1_size<types>, mpl::int_<SCHAR_MAX> >
, signed char
, int
>
>::type which_t;
#endif // BOOST_VARIANT_MINIMIZE_SIZE switch
which_t which_;
static bool using_storage1_impl(mpl::true_)
{
@@ -631,12 +672,12 @@ private: // representation (int which_)
void activate_storage1(int which)
{
which_ = which;
which_ = static_cast<which_t>( which );
}
void activate_storage2(int which)
{
which_ = -(which + 1);
which_ = static_cast<which_t>( -(which + 1) );
}
private: // representation (aligned double-storage)
@@ -735,7 +776,7 @@ private: // helpers, for structors (below)
{
private: // helpers, for static functions (below)
typedef typename Iterator::type
typedef typename BOOST_MPL_AUX_DEREF_WNKD(Iterator)
T;
public: // static functions
@@ -1297,7 +1338,7 @@ private: // helpers, for visitation support (below)
// Otherwise, tail recurse, checking next iteration:
typename mpl::next<Which>::type* next_which = 0;
typename NextIt::type* next_type = 0;
typename BOOST_MPL_AUX_DEREF_WNKD(NextIt)* next_type = 0;
typedef typename mpl::next<NextIt>::type next_next_it_t;
next_next_it_t* next_next_it = 0;
typedef typename is_same<next_next_it_t, LastIt>::type next_next_is_last;
@@ -1352,7 +1393,7 @@ public:
{
mpl::int_<0>* first_which = 0;
typedef typename mpl::begin<types>::type first_it;
typename first_it::type* first_type = 0;
typename BOOST_MPL_AUX_DEREF_WNKD(first_it)* first_type = 0;
typename mpl::next<first_it>::type* next_it = 0;
typename mpl::end<types>::type* last_it = 0;
@@ -1370,7 +1411,7 @@ public:
{
mpl::int_<0>* first_which = 0;
typedef typename mpl::begin<types>::type first_it;
typename first_it::type* first_type = 0;
typename BOOST_MPL_AUX_DEREF_WNKD(first_it)* first_type = 0;
typename mpl::next<first_it>::type* next_it = 0;
typename mpl::end<types>::type* last_it = 0;