53 lines
2.2 KiB
C++
53 lines
2.2 KiB
C++
/***************************************************************************
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* Copyright (C) 2008 by Sindre Aamås *
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* sinamas@users.sourceforge.net *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License version 2 as *
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* published by the Free Software Foundation. *
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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 version 2 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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* version 2 along with this program; if not, write to the *
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* Free Software Foundation, Inc., *
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. *
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***************************************************************************/
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#include "adaptivesleep.h"
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static usec_t absdiff(usec_t a, usec_t b) { return a < b ? b - a : a - b; }
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usec_t AdaptiveSleep::sleepUntil(usec_t base, usec_t inc) {
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usec_t now = getusecs();
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usec_t diff = now - base;
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if (diff >= inc)
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return diff - inc;
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diff = inc - diff;
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if (diff > oversleep_ + oversleepVar_) {
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diff -= oversleep_ + oversleepVar_;
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usecsleep(diff);
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usec_t const sleepTarget = now + diff;
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now = getusecs();
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usec_t curOversleep = now - sleepTarget;
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if (curOversleep > usec_t(-1) / 2)
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curOversleep = 0;
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oversleepVar_ = (oversleepVar_ * 15 + absdiff(curOversleep, oversleep_) + 8) >> 4;
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oversleep_ = (oversleep_ * 15 + curOversleep + 8) >> 4;
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noSleep_ = 60;
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} else if (--noSleep_ == 0) {
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noSleep_ = 60;
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oversleep_ = oversleepVar_ = 0;
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}
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while (now - base < inc)
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now = getusecs();
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return 0;
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}
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