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author | Lorry Tar Creator <lorry-tar-importer@lorry> | 2016-08-21 05:23:24 +0000 |
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committer | Lorry Tar Creator <lorry-tar-importer@lorry> | 2016-08-21 05:23:24 +0000 |
commit | a3ec215973c3653ebdeb81dcdd1274519c376a3d (patch) | |
tree | dc0edc2133786db0565f19d51c4a9957dd69e2ac /gnulib-tests/timespec-add.c | |
download | diffutils-tarball-a3ec215973c3653ebdeb81dcdd1274519c376a3d.tar.gz |
diffutils-3.5HEADdiffutils-3.5master
Diffstat (limited to 'gnulib-tests/timespec-add.c')
-rw-r--r-- | gnulib-tests/timespec-add.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/gnulib-tests/timespec-add.c b/gnulib-tests/timespec-add.c new file mode 100644 index 0000000..b093946 --- /dev/null +++ b/gnulib-tests/timespec-add.c @@ -0,0 +1,71 @@ +/* Add two struct timespec values. + + Copyright (C) 2011-2016 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 sum of two timespec values A and B. On overflow, return + an extremal value. This assumes 0 <= tv_nsec < TIMESPEC_RESOLUTION. */ + +#include <config.h> +#include "timespec.h" + +#include "intprops.h" + +struct timespec +timespec_add (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 nsd = ns - TIMESPEC_RESOLUTION; + int rns = ns; + time_t tmin = TYPE_MINIMUM (time_t); + time_t tmax = TYPE_MAXIMUM (time_t); + + if (0 <= nsd) + { + rns = nsd; + if (bs < tmax) + bs++; + else if (rs < 0) + rs++; + else + goto high_overflow; + } + + /* INT_ADD_WRAPV is not appropriate since time_t might be unsigned. + In theory time_t might be narrower than int, so plain + INT_ADD_OVERFLOW does not suffice. */ + if (! INT_ADD_OVERFLOW (rs, bs) && tmin <= rs + bs && rs + bs <= tmax) + rs += bs; + else + { + if (rs < 0) + { + rs = tmin; + rns = 0; + } + else + { + high_overflow: + rs = tmax; + rns = TIMESPEC_RESOLUTION - 1; + } + } + + return make_timespec (rs, rns); +} |