tlm_array.h

SystemC Transaction Level Modelling. 是基于SystemC之上的总线互联协议

/*****************************************************************************

  The following code is derived, directly or indirectly, from the SystemC
  source code Copyright (c) 1996-2008 by all Contributors.
  All Rights reserved.

  The contents of this file are subject to the restrictions and limitations
  set forth in the SystemC Open Source License Version 3.0 (the "License");
  You may not use this file except in compliance with such restrictions and
  limitations. You may obtain instructions on how to receive a copy of the
  License at http://www.systemc.org/. Software distributed by Contributors
  under the License is distributed on an "AS IS" basis, WITHOUT WARRANTY OF
  ANY KIND, either express or implied. See the License for the specific
  language governing rights and limitations under the License.

  Author: Olaf Scheufen
*****************************************************************************/

#ifndef __TLM_ARRAY_H__
#define __TLM_ARRAY_H__

#include <systemc>
#include <exception>
// unused for the time being: #include <assert.h>

namespace tlm {

//
// To the LRM writer: the below class is an artifact of the tlm_generic_payload
//                    implementation and not part of the core TLM standard
//


// This implements a lean and fast array class that supports array expansion on
// request. The class is primarily used in the tlm_generic_payload class for
// storing the pointers to the extensions.
//
// Individual array elements can be accessed through the [] operators, and the
// array length is returned by the size() method.
//
// The size can be dynamically expanded using the expand(uint) method. There
// is no shrinking mechanism implemented, because the extension mechanism
// does not require this feature. Bear in mind that calling the expand method
// may invalidate all direct pointers into the m_data array.


//the tlm_array shall always be used with T=tlm_extension_base*
template <typename T>
class tlm_array
{
public:

    // constructor:
    tlm_array(unsigned int size = 0, T default_value = 0)
        : m_data(0)
        , m_size(0)
        , m_entries(NULL)
        , m_last_entry(0)
        , m_default(default_value)
    {
        expand(size);
    }

    // copy constructor:
    tlm_array(const tlm_array& orig)
    {
        m_size = orig.size();
        m_last_entry=orig.m_last_entry;        
        if (m_size>0)
        {
            try {
                m_data = new T[m_size];
            }
            catch (std::exception &e) {
                report_error(e); return;
            }
            try {
                m_entries = new T*[m_size];
            }
            catch (std::exception &e) {
                report_error(e); return;
            }
            for(unsigned int i=0; i<m_size; i++)
            {
                m_data[i] = orig.m_data[i];
                m_entries[i] = orig.m_entries[i];
            }
        }
    }
    
    // destructor:
    ~tlm_array()
    {
        if (m_size>0) {delete[] m_data; delete [] m_entries;}
        m_size = 0;
    }

    // operators for dereferencing:
    T& operator[](const unsigned int index)
    {
        // assert(index < m_size);
        return m_data[index];
    }
    const T& operator[](const unsigned int index) const
    {
        // assert(index < m_size);
        return m_data[index];
    }

    // array size:
    unsigned int size() const {return m_size;}

    // expand the array if needed:
    void expand(unsigned int new_size)
    {
        if (new_size > m_size)
        {
            unsigned int i;
            if(m_size==0)
            {
                try {
                    m_data = new T[new_size];
                }
                catch (std::exception &e) {
                    report_error(e); return;
                }

                try {
                    m_entries = new T*[new_size];
                }
                catch (std::exception &e) {
                    report_error(e); return;
                }
                
                for(i=0; i<new_size; i++)
                {
                    m_data[i] = m_default;
                    m_entries[i] = NULL;
                }
                m_size = new_size;
                m_last_entry=0;
            }
            else
            {
                T* tmp = m_data;
                T** tmp2 = m_entries;
                try {
                    m_data = new T[new_size];
                }
                catch (std::exception &e) {
                    report_error(e); return;
                }
                try {
                    m_entries = new T*[new_size];
                }
                catch (std::exception &e) {
                    report_error(e); return;
                }
                
                for(i=0; i<m_size; i++)
                {
                    m_data[i] = tmp[i];
                }
                
                //since the array new the cache entries have to be update
                for (unsigned int j=0; j<m_size; j++)
                {
                    if (tmp[j]) //if there was a valid extension in the old array ...
                    {
                        for (unsigned int i=0; i<m_last_entry; i++) //...we search its position in the old cache
                        {
                            if (tmp[j]==(*tmp2[i])) //...and if it was in the old cache
                            {
                                 m_entries[i]=&m_data[j]; //...we put it into the same position in the new cache
                            }
                        }
                    }
                }
                
                for(i=m_size; i<new_size; i++)
                {
                    m_data[i] = m_default;
                    m_entries[i] = NULL;
                }
                m_size = new_size;
                delete[] tmp;
                delete[] tmp2;
            }
        }
    }

    static const char* const kind_string;
    const char* kind() const { return kind_string; }

    //this function shall get a pointer to a array slot
    // it stores this slot in a cache of active slots
    void insert_in_cache(T* p)
    {
        m_entries[m_last_entry++]=p;
    }

    //this functions clears all active slots of the array
    void free_entire_cache()
    {
        while(m_last_entry)
        {
            m_last_entry--;
            if (*m_entries[m_last_entry]) //we make sure no one cleared the slot manually
              (*m_entries[m_last_entry])->free(); //...and then we call free on the content of the slot
            *m_entries[m_last_entry]=0;   //afterwards we set the slot to NULL
        }
    }

protected:
    T* m_data;
    unsigned int m_size;

    T** m_entries;
    unsigned int m_last_entry;

    T m_default;

    // disabled:
    tlm_array& operator=(const tlm_array<T>&);
    
    // Report allocation error:
    void report_error(std::exception &e)
    {
        std::string msg("Allocation of array failed: ");
        msg += e.what();
        SC_REPORT_FATAL(kind_string, msg.c_str());
    }
};


template <typename T>
const char* const tlm_array<T>::kind_string = "tlm_array";

} // namespace tlm

#endif /* __TLM_ARRAY_H__ */