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move Variant to lib namespace, a bit of cleanup and clarifying the code

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This commit is contained in:
Fischlurch 2010-12-27 04:24:59 +01:00
parent 09d400d5bc
commit 9d91869098
2 changed files with 33 additions and 17 deletions
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48
src/lib/variant.hpp
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@ -27,18 +27,22 @@
** doesn't deal with alignment issues and is <b>not threadsafe</b>.
**
** Values can be stored using \c operator= . In order to access the value
** stored in lumiera::Variant, you additionally need to define a "functor"
** <ul><li>with a typedef "Ret" for the return type</li>
** <li>providing a <tt>static Ret access(ELM&)</tt> function
** for each of the types used in the Variant</li>
** </ul>
** stored in lib::Variant, you additionally need to define a "functor"
** - with a typedef "Ret" for the return type
** - providing a \code static Ret access(ELM&) \endcode function
** for each of the types used in the Variant</li>
**
** @todo the instance handling for the accessor seems somewhat
** misaligned: why do we create another accessor as static var
** within the access() function?? Why not putting that into the
** Holder::Storage instance created by the client code?
** @todo write an unit test ///////////////////////////////////////TICKET #141
** @see wrapperptr.hpp usage example
*/
#ifndef LUMIERA_VARIANT_H
#define LUMIERA_VARIANT_H
#ifndef LIB_VARIANT_H
#define LIB_VARIANT_H
#include "lib/meta/typelist-util.hpp"
@ -48,7 +52,7 @@
namespace lumiera {
namespace lib {
namespace variant {
@ -100,13 +104,13 @@ namespace lumiera {
put (T const& toStore)
{
BASE::deleteCurrent(); // remove old content, if any
//
T& storedObj = *new(BASE::buffer_) T (toStore);
BASE::which_ = idx; // remember the actual type selected
return storedObj;
}
using BASE::put;
using BASE::put; // inherited alternate put() for other types T
};
typedef InstantiateWithIndex< TYPES
@ -122,9 +126,9 @@ namespace lumiera {
struct CaseSelect
{
typedef typename FUNCTOR::Ret Ret;
typedef Ret (*Func)(Buffer&);
typedef Ret (Func)(Buffer&);
Func table_[TYPECNT];
Func* table_[TYPECNT];
CaseSelect ()
{
@ -146,11 +150,16 @@ namespace lumiera {
if (TYPECNT <= storage.which_)
return FUNCTOR::ifEmpty ();
else
return (*table_[storage.which_]) (storage);
{
Func& access = *table_[storage.which_];
return access (storage);
}
}
};
/** initialise the dispatcher (trampoline)
* for the case of accessing type T */
template< class T, class BASE, uint i >
struct CasePrepare
: BASE
@ -161,7 +170,14 @@ namespace lumiera {
}
};
/** access the variant's inline buffer,
* using the configured access functor.
* @note the actual accessor instance
* is created on demand (static)
* @todo shouldn't this rather be located within
* the Holder::Storage created by clients??
*/
template<class FUNCTOR>
static typename FUNCTOR::Ret
access (Buffer& buf)
@ -205,7 +221,7 @@ namespace lumiera {
/**
/**
* A variant wrapper (typesafe union) capable of holding a value of any
* of a bounded collection of types. The value is stored in a local buffer
* directly within the object and may be accessed by a typesafe visitation.
@ -273,5 +289,5 @@ namespace lumiera {
}
};
} // namespace lumiera
} // namespace lib
#endif

2
src/lib/wrapperptr.hpp
View file

@ -55,7 +55,7 @@ namespace lumiera {
* error reporting is similar to the behaviour of dynamic_cast<T>: when retrieving
* a pointer, NULL is returned in case of mismatch.
*/
typedef lumiera::Variant<WrapperTypes, util::AccessCasted> WrapperPtr;
typedef lib::Variant<WrapperTypes, util::AccessCasted> WrapperPtr;