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sc_temporary.h -- Temporary value pool classes.
Original Author: Andy Goodrich, Forte Design Systems, Inc.
#include <cstddef> // std::size_t
namespace sc_core
// This facility implements a heap of temporary byte allocations. Once an
// request has been allocated it is not freed. However the entire heap
// wraps and the storage is reused. This means that no allocations should
// be assumed as permanent. Allocations are double-word aligned. This is
// raw storage, so objects which contain virtual methods cannot be allocated
// with this object. See the sc_vpool object for that type of storage
// allocation.
// char* allocate( int size )
// This method returns a pointer to block of size bytes. The block
// returned is the next available one in the heap. If the current heap
// cannot fullfil the request it will be rewound and storage allocated from
// its start. All allocations start on an 8-byte boundary.
// size = number of bytes to be allocated.
// void initialize( int heap_size=0x100000 )
// This method allocates the storage to be managed. If there is already
// a block of storage under management it is freed. If no argument is
// provided for the heap size, a megabyte will be allocated.
// heap_size = number of bytes to allocate for the heap.
// unsigned int length()
// This method returns the size of this object's heap in bytes.
// sc_byte_heap()
// This is the non-initialized object instance constructor. It does not
// allocate the heap storage, that is done by the initialize() method.
// sc_byte_heap(int)
// This is the initializing object instance constructor. It does allocates
// a heap of the specified number of bytes.
// heap_size = number of bytes to allocate for the heap.
class sc_byte_heap
char *m_bgn_p; // Beginning of heap storage.
char *m_end_p; // End of heap storage.
char *m_next_p; // Next heap location to be allocated.
inline char *
allocate(std::size_t bytes_n)
char *result_p;
bytes_n = (bytes_n + 7) & ((std::size_t)(-8));
result_p = m_next_p;
m_next_p += bytes_n;
if (m_next_p >= m_end_p) {
result_p = m_bgn_p;
m_next_p = m_bgn_p + bytes_n;
return result_p;
inline void
initialize(std::size_t heap_size=0x100000)
delete [] m_bgn_p;
m_bgn_p = new char[heap_size];
m_end_p = &m_bgn_p[heap_size];
m_next_p = m_bgn_p;
inline std::size_t
return (std::size_t)(m_end_p - m_bgn_p);
inline sc_byte_heap() : m_bgn_p(0), m_end_p(0), m_next_p(0) {}
inline sc_byte_heap(std::size_t heap_size) :
m_bgn_p(0), m_end_p(0), m_next_p(0)
inline ~sc_byte_heap() { delete [] m_bgn_p; }
// 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
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.
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>
// 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 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.