qeq_fifo.cpp

00001 //////////////////////////////////////////////////////////////////////////////
00002 // Product: QF/C++
00003 // Last Updated for Version: 4.0.00
00004 // Date of the Last Update:  Apr 07, 2008
00005 //
00006 //                    Q u a n t u m     L e a P s
00007 //                    ---------------------------
00008 //                    innovating embedded systems
00009 //
00010 // Copyright (C) 2002-2008 Quantum Leaps, LLC. All rights reserved.
00011 //
00012 // This software may be distributed and modified under the terms of the GNU
00013 // General Public License version 2 (GPL) as published by the Free Software
00014 // Foundation and appearing in the file GPL.TXT included in the packaging of
00015 // this file. Please note that GPL Section 2[b] requires that all works based
00016 // on this software must also be made publicly available under the terms of
00017 // the GPL ("Copyleft").
00018 //
00019 // Alternatively, this software may be distributed and modified under the
00020 // terms of Quantum Leaps commercial licenses, which expressly supersede
00021 // the GPL and are specifically designed for licensees interested in
00022 // retaining the proprietary status of their code.
00023 //
00024 // Contact information:
00025 // Quantum Leaps Web site:  http://www.quantum-leaps.com
00026 // e-mail:                  info@quantum-leaps.com
00027 //////////////////////////////////////////////////////////////////////////////
00028 #include "qf_pkg.h"
00029 #include "qassert.h"
00030 
00031 Q_DEFINE_THIS_MODULE(qeq_fifo)
00032 
00033 /// \file
00034 /// \ingroup qf
00035 /// \brief QEQueue::postFIFO() implementation.
00036 
00037 //............................................................................
00038 void QEQueue::postFIFO(QEvent const *e) {
00039     QF_INT_LOCK_KEY_
00040     QF_INT_LOCK_();
00041 
00042     QS_BEGIN_NOLOCK_(QS_QF_EQUEUE_POST_FIFO, QS::eqObj_, this)
00043         QS_TIME_();                                               // timestamp
00044         QS_SIG_(e->sig);                           // the signal of this event
00045         QS_OBJ_(this);                                    // this queue object
00046         QS_U8_(e->dynamic_);            // the dynamic attributes of the event
00047         QS_EQC_(m_nFree);                            // number of free entries
00048         QS_EQC_(m_nMin);                         // min number of free entries
00049     QS_END_NOLOCK_()
00050 
00051     if (e->dynamic_ != (uint8_t)0) {                    // is it a pool event?
00052         //lint -e1773                               Attempt to cast away const
00053         ++((QEvent *)e)->dynamic_;          // increment the reference counter
00054                    // NOTE: cast the 'const' away, which is legitimate because
00055                    // it's a dynamic event
00056     }
00057 
00058     if (m_frontEvt == (QEvent *)0) {                    // is the queue empty?
00059         m_frontEvt = e;                              // deliver event directly
00060     }
00061     else {               // queue is not empty, leave event in the ring-buffer
00062                // the queue must be able to accept the event (cannot overflow)
00063         Q_ASSERT(m_nFree != (QEQueueCtr)0);
00064 
00065         m_ring[m_head] = e;             // insert event into the buffer (FIFO)
00066         if (m_head == (QEQueueCtr)0) {               // need to wrap the head?
00067             m_head = m_end;                                     // wrap around
00068         }
00069         --m_head;
00070 
00071         --m_nFree;                             // update number of free events
00072         if (m_nMin > m_nFree) {
00073             m_nMin = m_nFree;                         // update minimum so far
00074         }
00075     }
00076     QF_INT_UNLOCK_();
00077 }