1
0
Fork 0
mirror of https://gitlab.com/sortix/sortix.git synced 2023-02-13 20:55:38 -05:00
sortix--sortix/libc/timespec.cpp
2013-12-17 14:30:26 +01:00

60 lines
1.9 KiB
C++

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