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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:46:38 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-05 18:46:38 +0000 |
commit | a06ac93dcf311dac3943cb5d96ad47625d413c2d (patch) | |
tree | 6efda5e24896e7920ccac1f97aecc73406525040 /gnulib-tests/timespec-sub.c | |
parent | Initial commit. (diff) | |
download | coreutils-upstream.tar.xz coreutils-upstream.zip |
Adding upstream version 8.30.upstream/8.30upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'gnulib-tests/timespec-sub.c')
-rw-r--r-- | gnulib-tests/timespec-sub.c | 71 |
1 files changed, 71 insertions, 0 deletions
diff --git a/gnulib-tests/timespec-sub.c b/gnulib-tests/timespec-sub.c new file mode 100644 index 0000000..398a6a5 --- /dev/null +++ b/gnulib-tests/timespec-sub.c @@ -0,0 +1,71 @@ +/* Subtract two struct timespec values. + + Copyright (C) 2011-2018 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 <https://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 < + TIMESPEC_RESOLUTION. */ + +#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; + time_t tmin = TYPE_MINIMUM (time_t); + time_t tmax = TYPE_MAXIMUM (time_t); + + if (ns < 0) + { + rns = ns + TIMESPEC_RESOLUTION; + if (bs < tmax) + bs++; + else if (- TYPE_SIGNED (time_t) < rs) + rs--; + else + goto low_overflow; + } + + /* INT_SUBTRACT_WRAPV is not appropriate since time_t might be unsigned. + In theory time_t might be narrower than int, so plain + INT_SUBTRACT_OVERFLOW does not suffice. */ + if (! INT_SUBTRACT_OVERFLOW (rs, bs) && tmin <= rs - bs && rs - bs <= tmax) + rs -= bs; + else + { + if (rs < 0) + { + low_overflow: + rs = tmin; + rns = 0; + } + else + { + rs = tmax; + rns = TIMESPEC_RESOLUTION - 1; + } + } + + return make_timespec (rs, rns); +} |