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Fixed swap between stack and heap-backup variants (correctness at expense of efficiency...).

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[SVN r20978]
This commit is contained in:
Eric Friedman
2003-11-28 05:04:05 +00:00
parent 5175d5dce8
commit 4e88342d88
1 changed files with 15 additions and 27 deletions
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42
include/boost/variant/variant.hpp
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@@ -642,20 +642,21 @@ public: // visitor interface
///////////////////////////////////////////////////////////////////////////////
// (detail) class swap_with
//
// Internal visitor that swaps visited value with given storage.
// Visitor that swaps visited value with content of given variant.
//
// Precondition: Given storage MUST have same content type as visited value.
// Precondition: Given variant MUST have same logical type as visited value.
//
template <typename Variant>
struct swap_with
: public static_visitor<>
{
private: // representation
void* toswap_;
Variant& toswap_;
public: // structors
explicit swap_with(void* toswap)
explicit swap_with(Variant& toswap)
: toswap_(toswap)
{
}
@@ -663,27 +664,14 @@ public: // structors
public: // internal visitor interfaces
template <typename T>
BOOST_VARIANT_AUX_RETURN_VOID_TYPE
internal_visit(backup_holder<T>& operand, long) const
void operator()(T& operand) const
{
operand.swap( *static_cast< backup_holder<T>* >(toswap_) );
BOOST_VARIANT_AUX_RETURN_VOID;
}
// Since the precondition ensures types are same, get T...
known_get<T> getter;
T& other = toswap_.apply_visitor(getter);
template <typename T>
BOOST_VARIANT_AUX_RETURN_VOID_TYPE
internal_visit(boost::recursive_wrapper<T>& operand, long) const
{
operand.swap( *static_cast< boost::recursive_wrapper<T>* >(toswap_) );
BOOST_VARIANT_AUX_RETURN_VOID;
}
template <typename T>
BOOST_VARIANT_AUX_RETURN_VOID_TYPE
internal_visit(T& operand, int) const
{
::boost::detail::variant::move_swap(operand, *static_cast<T*>(toswap_));
BOOST_VARIANT_AUX_RETURN_VOID;
// ...and swap:
::boost::detail::variant::move_swap( operand, other );
}
};
@@ -1606,12 +1594,12 @@ public: // modifiers
void swap(variant& rhs)
{
// If the contained internal types are EXACTLY the same...
if (which_ == rhs.which_)
// If the contained types are the same...
if (which() == rhs.which())
{
// ...then swap the values directly:
detail::variant::swap_with visitor(storage_.address());
rhs.internal_apply_visitor(visitor);
detail::variant::swap_with<variant> visitor(rhs);
this->apply_visitor(visitor);
}
else
{