61 lines
1.9 KiB
C++
61 lines
1.9 KiB
C++
/*******************************************************************************
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Copyright(C) Jonas 'Sortie' Termansen 2013.
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This file is part of the Sortix C Library.
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The Sortix C Library is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation, either version 3 of the License, or (at your
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option) any later version.
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The Sortix C Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
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or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public
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License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with the Sortix C Library. If not, see <http://www.gnu.org/licenses/>.
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timespec.cpp
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Utility functions for manipulation of struct timespec.
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*******************************************************************************/
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#include <timespec.h>
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static const long NANOSECONDS_PER_SECOND = 1000000000L;
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// TODO: The C modulo operator doesn't do exactly what we desire.
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static long proper_modulo(long a, long b)
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{
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if ( 0 <= a )
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return a % b;
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long tmp = - (unsigned long) a % b;
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return tmp ? tmp : 0;
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}
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extern "C" struct timespec timespec_canonalize(struct timespec t)
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{
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t.tv_sec += t.tv_nsec / NANOSECONDS_PER_SECOND;
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t.tv_nsec = proper_modulo(t.tv_nsec, NANOSECONDS_PER_SECOND);
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return t;
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}
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extern "C" struct timespec timespec_add(struct timespec a, struct timespec b)
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{
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struct timespec ret;
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a = timespec_canonalize(a);
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b = timespec_canonalize(b);
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ret.tv_sec = a.tv_sec + b.tv_sec;
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ret.tv_nsec = a.tv_nsec + b.tv_nsec;
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return timespec_canonalize(ret);
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}
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extern "C" struct timespec timespec_sub(struct timespec a, struct timespec b)
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{
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a = timespec_canonalize(a);
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b = timespec_canonalize(b);
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return timespec_add(a, timespec_neg(b));
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}
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