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#ifndef THREADSPECIFICDATA_H
#define THREADSPECIFICDATA_H
#include <cstdlib>
/** Support class for ThreadSpecificData */
class ThreadSpecificDataSupport
{
public:
ThreadSpecificDataSupport();
~ThreadSpecificDataSupport();
/**
Get a pointer to the cached data, allocating memory of data_size bytes
if cached data does not exist. The data will be automatically deallocated
when the thread terminates
*/
void *GetPtrCreateIfNeeded(size_t datasize);
/**
Get a pointer. If it has not been created (a value already assigned),
then this will return NULL.
*/
void *GetPtr() const;
protected:
static void Deleter(void *p);
// The key. To avoid having to do platform-specific stuff here,
// we just make this key a void pointer. The key is used to create
// specific data objects;
void *m_KeyPointer;
};
/**
Encapsulates the functionality provided by pthread_key_create,
pthread_getspecific and pthread_setspecific. This allows an instance
of an atomic type to be cached on a per-thread basis. To use this class
in an ITK filter, just add a variable of this type to the class. Then,
inside of the threaded code, use the object as you would a regular variable
to set and get the values.
*/
template <class TAtomic>
class ThreadSpecificData
{
public:
typedef ThreadSpecificData<TAtomic> Self;
/**
Assign a value to the cache. Make sure to do this before trying to access
the value using the cast operator below, or you will get a segfault.
*/
Self & operator = (const TAtomic &value)
{
TAtomic *p = (TAtomic *)(m_Support.GetPtrCreateIfNeeded(sizeof(TAtomic)));
*p = value;
return *this;
}
/**
Get the value from the cache. If the value has not been previously set,
this will probably segfault. For speed, there is no check implemented!
*/
operator TAtomic() const
{
TAtomic *p = (TAtomic *)(m_Support.GetPtr());
return *p;
}
protected:
ThreadSpecificDataSupport m_Support;
};
#endif // THREADSPECIFICDATA_H
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