blob: 97c9f9de88c448ff6794eb743d2a3c70059d8ab8 (
about) (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
|
/* Subtract two struct timespec values.
Copyright (C) 2011-2013 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program 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 General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <http://www.gnu.org/licenses/>. */
/* Written by Paul Eggert. */
/* Return the difference between two timespec values A and B. On
overflow, return an extremal value. This assumes 0 <= tv_nsec <=
999999999. */
#include <config.h>
#include "timespec.h"
#include "intprops.h"
struct timespec
timespec_sub (struct timespec a, struct timespec b)
{
struct timespec r;
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 + 1000000000;
if (rs == TYPE_MINIMUM (time_t))
{
if (bs <= 0)
goto low_overflow;
bs--;
}
else
rs--;
}
if (INT_SUBTRACT_OVERFLOW (rs, bs))
{
if (rs < 0)
{
low_overflow:
rs = TYPE_MINIMUM (time_t);
rns = 0;
}
else
{
rs = TYPE_MAXIMUM (time_t);
rns = 999999999;
}
}
else
rs -= bs;
r.tv_sec = rs;
r.tv_nsec = rns;
return r;
}
|
