sc_temporary.h

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/*****************************************************************************
 
  sc_temporary.h -- Temporary value pool classes.
 
  Original Author: Andy Goodrich, Forte Design Systems, Inc.
 
  CHANGE LOG AT END OF FILE
 *****************************************************************************/
 
#ifndef SC_TEMPORARY_H
#define SC_TEMPORARY_H
#include "sysc/kernel/sc_cmnhdr.h"
 
#include <cstddef>                // std::size_t
 
namespace sc_core {
 
//------------------------------------------------------------------------------
// sc_vpool<T> - CLASS MANAGING A TEMPORARY VECTOR OF CLASS T INSTANCES
//
// This class implements a fixed pool of objects contained in a vector. These
// objects are allocated via the allocate() method. An index, m_pool_i, 
// indicates the next object to be allocated. The vector is a power of 2 in
// size, and this fact is used to wrap the list when m_pool_i reaches the
// end of the vector.  
// 
// sc_vpool( int log2, T* pool_p=0 )
//   This is the object instance constructor for this class. It configures
//   the object to manage a vector of 2**log2 entries. If a vector is 
//   not supplied one will be allocated.
//     log2   =  the log base two of the size of the vector.
//     pool_p -> vector of 2**log2 entries to be managed or 0.
//
// ~sc_vpool()
//   This is the object instance destructor for this class. It frees the
//   block of storage which was being managed.
//
// T* allocate()
//   This method returns the address of the next entry in the vector, m_pool_p, 
//   pointed to by the index, m_pool_i, and updates that index. The index
//   update consists of adding 1 to m_pool_i and masking it by m_wrap.
// 
// void reset()
//   This method resets the allocation index, m_pool_i, to point to the start
//   of the vector of objects under management. This call is not usually made
//   since there are a fixed number of entries and the index wraps. However,
//   for diagnostics tests it is convenient to be able to reset to the start
//   of the vector.
//
// int size()
//   This method returns the number of object instances contained in the
//   vector being managed by this object instance.
//------------------------------------------------------------------------------
template<class T>
class sc_vpool {
  protected:
        std::size_t m_pool_i;   // Index of next entry to m_pool_m to provide.
        T*          m_pool_p;   // Vector of temporaries.
        std::size_t m_wrap;             // Mask to wrap vector index.
 
  public:
        inline sc_vpool( int log2, T* pool_p=0 );
        inline ~sc_vpool();
        inline T* allocate();
        inline void reset();
        inline std::size_t size();
};
 
template<class T> sc_vpool<T>::sc_vpool( int log2, T* pool_p )
  : m_pool_i( 0 )
  , m_pool_p( pool_p ? pool_p : new T[static_cast<std::size_t>(1) << log2] )
  , m_wrap( ~(static_cast<std::size_t>(-1) << log2) )
{
        // if ( log2 > 32 ) SC_REPORT_ERROR(SC_ID_POOL_SIZE_, "");
}
 
template<class T> sc_vpool<T>::~sc_vpool()
{
        // delete [] m_pool_p;
}
 
template<class T> T* sc_vpool<T>::allocate()
{
        T* result_p;    // Entry to return.
 
        result_p = &m_pool_p[m_pool_i];
        m_pool_i = (m_pool_i + 1) & m_wrap;
        return result_p;
}
 
template<class T> void sc_vpool<T>::reset()
{
        m_pool_i = 0;
}
 
template<class T> std::size_t sc_vpool<T>::size()
{
        return m_wrap + 1;
}
 
} // namespace sc_core
 
// $Log: sc_temporary.h,v $
// Revision 1.4  2011/08/26 20:46:19  acg
//  Andy Goodrich: moved the modification log to the end of the file to
//  eliminate source line number skew when check-ins are done.
//
// Revision 1.3  2011/08/24 22:05:56  acg
//  Torsten Maehne: initialization changes to remove warnings.
//
// Revision 1.2  2011/02/18 20:38:44  acg
//  Andy Goodrich: Updated Copyright notice.
//
// Revision 1.1.1.1  2006/12/15 20:20:06  acg
// SystemC 2.3
//
// Revision 1.3  2006/01/13 18:53:11  acg
// Andy Goodrich: Added $Log command so that CVS comments are reproduced in
// the source.
//
 
#endif // SC_TEMPORARY_H