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78 lines
3.0 KiB
C++
78 lines
3.0 KiB
C++
//****************************************************************************
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// Product: QS/C++
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// Last Updated for Version: 5.1.0
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// Date of the Last Update: Sep 23, 2013
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//
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// Q u a n t u m L e a P s
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// ---------------------------
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// innovating embedded systems
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//
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// Copyright (C) 2002-2013 Quantum Leaps, LLC. All rights reserved.
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//
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// This program is open source software: you can redistribute it and/or
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// modify it under the terms of the GNU General Public License as published
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// by the Free Software Foundation, either version 2 of the License, or
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// (at your option) any later version.
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//
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// Alternatively, this program may be distributed and modified under the
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// terms of Quantum Leaps commercial licenses, which expressly supersede
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// the GNU General Public License and are specifically designed for
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// licensees interested in retaining the proprietary status of their code.
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//
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// This program is distributed in the hope that it will be useful,
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// but WITHOUT ANY WARRANTY; without even the implied warranty of
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// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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// GNU General Public License for more details.
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//
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// You should have received a copy of the GNU General Public License
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// along with this program. If not, see <http://www.gnu.org/licenses/>.
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//
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// Contact information:
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// Quantum Leaps Web sites: http://www.quantum-leaps.com
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// http://www.state-machine.com
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// e-mail: info@quantum-leaps.com
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//****************************************************************************
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#include "qs_pkg.h"
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/// \file
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/// \ingroup qs
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/// \brief QS::getBlock() implementation
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namespace QP {
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//............................................................................
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// get up to *pn bytes of contiguous memory
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uint8_t const *QS::getBlock(uint16_t * const pNbytes) {
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QSCtr used_ = priv_.used; // put in a temporary (register)
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uint8_t *buf_;
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if (used_ == static_cast<QSCtr>(0)) {
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*pNbytes = static_cast<uint16_t>(0); // no bytes available right now
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buf_ = static_cast<uint8_t *>(0); // no bytes available right now
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}
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else {
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QSCtr tail_ = priv_.tail; // put in a temporary (register)
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QSCtr end_ = priv_.end; // put in a temporary (register)
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QSCtr n = static_cast<QSCtr>(end_ - tail_);
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if (n > used_) {
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n = used_;
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}
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if (n > static_cast<QSCtr>(*pNbytes)) {
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n = static_cast<QSCtr>(*pNbytes);
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}
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*pNbytes = static_cast<uint16_t>(n); // n-bytes available
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buf_ = priv_.buf;
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buf_ = QS_PTR_AT_(tail_); // the bytes are at the tail
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priv_.used -= n;
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tail_ += n;
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if (tail_ == end_) {
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tail_ = static_cast<QSCtr>(0);
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}
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priv_.tail = tail_;
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}
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return buf_;
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}
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} // namespace QP
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