ofutil.h File Reference

Implement fallback support for modern techniques defined in the STL's <utility> header (e.g. move semantics) for older compilers. More...

Classes
struct	OFrvalue< T >
	A helper class to 'tag' objects as rvalues to help DCMTK's move emulation employed on pre C++11 compilers. More...
class	OFPair< K, V >
	a pair - this implements parts of std::pair's interface. More...
struct	OFtuple_size< Tuple >
struct	OFtuple_element< Index, Tuple >
struct	OFtuple_size< OFPair< K, V > >
struct	OFtuple_element< 0, OFPair< K, V > >
struct	OFtuple_element< 1, OFPair< K, V > >
struct	OFpair_element< Element >
struct	OFpair_element< 0 >
struct	OFpair_element< 1 >

Macros
#define	OFrvalue_ref(T)   unspecified
	Determines rvalue reference type for the type T. More...
#define	OFrvalue_ref_upcast(T, RV)   unspecified
	Upcast an rvalue reference to an rvalue reference of one of its bases. More...

Functions
template<typename T >
T &	OFrvalue_access (OFrvalue_ref(T) rv)
	Obtain an lvalue reference from an rvalue reference. More...
template<typename T >
OFconstexpr xvalue	OFmove (T< unspecified > t)
	Obtains an rvalue reference to its argument and converts it to an xvalue. More...
template<typename T >
void	OFswap (T &t0, T &t1)
	Exchanges the given values. More...

Detailed Description

Implement fallback support for modern techniques defined in the STL's <utility> header (e.g. move semantics) for older compilers.

---

Class Documentation

OFtuple_size

struct OFtuple_size

template<typename Tuple>
struct OFtuple_size< Tuple >

OFtuple_element

struct OFtuple_element

template<size_t Index, typename Tuple>
struct OFtuple_element< Index, Tuple >

OFtuple_element< 0, OFPair< K, V > >

struct OFtuple_element< 0, OFPair< K, V > >

template<typename K, typename V>
struct OFtuple_element< 0, OFPair< K, V > >

OFtuple_element< 1, OFPair< K, V > >

struct OFtuple_element< 1, OFPair< K, V > >

template<typename K, typename V>
struct OFtuple_element< 1, OFPair< K, V > >

OFpair_element

struct OFpair_element

template<size_t Element>
struct OFpair_element< Element >

Macro Definition Documentation

OFrvalue_ref

#define OFrvalue_ref

(

T

)

unspecified

Determines rvalue reference type for the type T.

Parameters

T	the base type to determine the rvalue reference type for.

Note

OFrvalue_ref(T) will expand to T&& when C++11 support is available. Otherwise DCMTK's move emulation will be used, employing an unspecified type to implement rvalue references.

Example

This example shows how to implement the move constructor and move assignment for a custom class in a portable fashion (employing C++11's native features when available and using DCMTK's move emulation otherwise).

class MyMovable
{
public:
  MyMovable( OFrvalue_ref(MyMovable) rhs )
  : m_hDatabase( rhs.m_hDatabase )
  {
    // You need to use OFrvalue_access to get write access
    // to rvalue references when DCMTK's move emulation
    // is used.
    OFrvalue_access(rhs).m_hDatabase = OFnullptr;
  }

  MyMovable& operator=( OFrvalue_ref(MyMovable) rvrhs )
  {
    // You may bind the rvalue reference to an lvalue
    // reference to ease access.
    MyMovable& rhs = OFrvalue_access(rvrhs);
    if( this != &rhs )
    {
      disconnectDatabase( m_hDatabase );
      m_hDatabase = rhs.m_hDatabase;
      rhs.m_hDatabase = OFnullptr;
    }
    return *this;
  }
};

OFrvalue_ref_upcast

#define OFrvalue_ref_upcast	(		T,
			RV
	)		unspecified

Upcast an rvalue reference to an rvalue reference of one of its bases.

This is a helper macro for being used with DCMTK's fallback implementation of move semantics. C++11 rvalue references should normally allow implicit upcasts, therefore, this macro typically has no effect if C++11 is enabled (it may be used to work around the behavior of older GCC versions).

Parameters

T	the base class to upcast to
RV	the rvalue reference to upcast

Function Documentation

OFmove()

template<typename T >

OFconstexpr xvalue OFmove

(

T< unspecified >

t

)

Obtains an rvalue reference to its argument and converts it to an xvalue.

OFmove is meant to 'mark' an object for a move operation, e.g. to move an OFVector object into another OFVector instance instead of copying it.

Note

OFmove will be an alias for std::move when native move semantics are supported (C++11 support is available). Otherwise DCMTK's move emulation will be used. This means you will have to specify rvalues (e.g. function return values) employing the OFrvalue class template.

Parameters

t	The object to move.

See also

OFrvalue

OFrvalue_ref

OFrvalue_access()

template<typename T >

T& OFrvalue_access

(

OFrvalue_ref(T)

rv

)

Obtain an lvalue reference from an rvalue reference.

DCMTK's move emulations does restrict write access to rvalue references due to compiler limitations. This method enables you to workaround this restriction by converting DCMTK's emulated rvalue references to lvalue references.

Note

Native rvalue references from C++11 don't need this workaround, therefore OFrvalue_access has no effect when C++11 support is available.

Parameters

rv	an rvalue reference, e.g. the parameter of a move constructor.

OFswap()

template<typename T >

void OFswap	(	T &	t0,
		T &	t1
	)

Exchanges the given values.

OFswap is an alias for std::swap if C++11 is supported. Otherwise OFswap simply creates a temporary copy of one argument to exchange both values.

Note

As intended for std::swap, there are some specializations for OFswap available, e.g. for OFoptional, which specializes OFswap to exchange optional objects more efficiently. When creating your own specializations for OFswap, make sure to specialize std::swap instead when C++11 support is available.

Parameters

t0	An object to be exchanged.
t1	The object to be exchanged with t0.

Referenced by DSRTree< DSRDocumentTreeNode >::swap().