qs_byte.cpp

00001 //////////////////////////////////////////////////////////////////////////////
00002 // Product: QS/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 "qs_pkg.h"
00029 
00030 /// \file
00031 /// \ingroup qs
00032 /// \brief QS::getByte() implementation
00033 
00034 //............................................................................
00035 uint16_t QS::getByte(void) {
00036     if (QS_used_ == (QSCtr)0) {
00037         return QS_EOD;                                   // return End-Of-Data
00038     }
00039     uint8_t byte = QS_ring_[QS_tail_];               // set the byte to return
00040     ++QS_tail_;                                            // advance the tail
00041     if (QS_tail_ == QS_end_) {                            // tail wrap around?
00042         QS_tail_ = (QSCtr)0;
00043     }
00044     --QS_used_;                                          // one less byte used
00045     return (uint16_t)byte;                                  // return the byte
00046 }