qa_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(qa_fifo)
00032 
00033 /// \file
00034 /// \ingroup qf
00035 /// \brief QActive::postFIFO() implementation.
00036 ///
00037 /// \note this source file is only included in the QF library when the native
00038 /// QF active object queue is used (instead of a message queue of an RTOS).
00039 
00040 //............................................................................
00041 void QActive::postFIFO(QEvent const *e) {
00042     QF_INT_LOCK_KEY_
00043     QF_INT_LOCK_();
00044 
00045     QS_BEGIN_NOLOCK_(QS_QF_ACTIVE_POST_FIFO, QS::aoObj_, this)
00046         QS_TIME_();                                               // timestamp
00047         QS_SIG_(e->sig);                            // the signal of the event
00048         QS_OBJ_(this);                                   // this active object
00049         QS_U8_(e->dynamic_);                  // the QF attribute of the event
00050         QS_EQC_(m_eQueue.m_nFree);                   // number of free entries
00051         QS_EQC_(m_eQueue.m_nMin);                // min number of free entries
00052     QS_END_NOLOCK_()
00053 
00054     if (e->dynamic_ != (uint8_t)0) {                 // is it a dynamic event?
00055         //lint -e1773                               Attempt to cast away const
00056         ++((QEvent *)e)->dynamic_;          // increment the reference counter
00057                    // NOTE: cast the 'const' away, which is legitimate because
00058                    // it's a dynamic event
00059     }
00060 
00061     if (m_eQueue.m_frontEvt == (QEvent *)0) {           // is the queue empty?
00062         m_eQueue.m_frontEvt = e;                     // deliver event directly
00063         QACTIVE_EQUEUE_SIGNAL_(this);                // signal the event queue
00064     }
00065     else {               // queue is not empty, leave event in the ring-buffer
00066                                         // queue must accept all posted events
00067         Q_ASSERT(m_eQueue.m_nFree != (QEQueueCtr)0);
00068         m_eQueue.m_ring[m_eQueue.m_head] = e;//insert e into the buffer (FIFO)
00069         if (m_eQueue.m_head == (QEQueueCtr)0) {      // need to wrap the head?
00070             m_eQueue.m_head = m_eQueue.m_end;                   // wrap around
00071         }
00072         --m_eQueue.m_head;
00073 
00074         --m_eQueue.m_nFree;                    // update number of free events
00075         if (m_eQueue.m_nMin > m_eQueue.m_nFree) {
00076             m_eQueue.m_nMin = m_eQueue.m_nFree;       // update minimum so far
00077         }
00078     }
00079     QF_INT_UNLOCK_();
00080 }