mirror of
https://sourceware.org/git/glibc.git
synced 2024-11-08 22:30:07 +00:00
66 lines
1.8 KiB
C
66 lines
1.8 KiB
C
/* Subtract two struct timespec values.
|
|
Copyright (C) 2011-2023 Free Software Foundation, Inc.
|
|
This file is part of the GNU C Library and is also part of gnulib.
|
|
Patches to this file should be submitted to both projects.
|
|
|
|
The GNU 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 2.1 of the License, or (at your option) any later version.
|
|
|
|
The GNU 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 GNU C Library; if not, see
|
|
<https://www.gnu.org/licenses/>. */
|
|
|
|
/* Return the difference between two timespec values A and B. On
|
|
overflow, return an extremal value. This assumes 0 <= tv_nsec <
|
|
TIMESPEC_HZ. */
|
|
|
|
#include <config.h>
|
|
#include "timespec.h"
|
|
|
|
#include "intprops.h"
|
|
|
|
struct timespec
|
|
timespec_sub (struct timespec a, struct timespec b)
|
|
{
|
|
time_t rs = a.tv_sec;
|
|
time_t bs = b.tv_sec;
|
|
int ns = a.tv_nsec - b.tv_nsec;
|
|
int rns = ns;
|
|
|
|
if (ns < 0)
|
|
{
|
|
rns = ns + TIMESPEC_HZ;
|
|
time_t bs1;
|
|
if (!INT_ADD_WRAPV (bs, 1, &bs1))
|
|
bs = bs1;
|
|
else if (- TYPE_SIGNED (time_t) < rs)
|
|
rs--;
|
|
else
|
|
goto low_overflow;
|
|
}
|
|
|
|
if (INT_SUBTRACT_WRAPV (rs, bs, &rs))
|
|
{
|
|
if (0 < bs)
|
|
{
|
|
low_overflow:
|
|
rs = TYPE_MINIMUM (time_t);
|
|
rns = 0;
|
|
}
|
|
else
|
|
{
|
|
rs = TYPE_MAXIMUM (time_t);
|
|
rns = TIMESPEC_HZ - 1;
|
|
}
|
|
}
|
|
|
|
return (struct timespec) { .tv_sec = rs, .tv_nsec = rns };
|
|
}
|