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author | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2017-03-27 21:42:03 +0200 |
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committer | Jörg Frings-Fürst <debian@jff-webhosting.net> | 2017-03-27 21:42:03 +0200 |
commit | db6f1f397f45ccd3c11d16352ed46a9c1eae3442 (patch) | |
tree | e0b9334e2637f17696c796ac13b2c39294bf9233 /lib/flexmember.h | |
parent | 0250cb64565a7d5238bbc751225d4b0236ef8316 (diff) | |
parent | 6b73edd95d603e27d55d4905134ac1327d426534 (diff) |
Merge tag 'upstream/0.9.7'
Upstream version 0.9.7
Diffstat (limited to 'lib/flexmember.h')
-rw-r--r-- | lib/flexmember.h | 51 |
1 files changed, 51 insertions, 0 deletions
diff --git a/lib/flexmember.h b/lib/flexmember.h new file mode 100644 index 00000000..c829ea6c --- /dev/null +++ b/lib/flexmember.h @@ -0,0 +1,51 @@ +/* Sizes of structs with flexible array members. + + Copyright 2016 Free Software Foundation, Inc. + + This program is free software: you can redistribute it and/or + modify it under the terms of either: + + * 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. + + or + + * the GNU General Public License as published by the Free + Software Foundation; either version 2 of the License, or (at your + option) any later version. + + or both in parallel, as here. + 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. */ + +#include <stddef.h> + +/* Nonzero multiple of alignment of TYPE, suitable for FLEXSIZEOF below. + On older platforms without _Alignof, use a pessimistic bound that is + safe in practice even if FLEXIBLE_ARRAY_MEMBER is 1. + On newer platforms, use _Alignof to get a tighter bound. */ + +#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112 +# define FLEXALIGNOF(type) (sizeof (type) & ~ (sizeof (type) - 1)) +#else +# define FLEXALIGNOF(type) _Alignof (type) +#endif + +/* Upper bound on the size of a struct of type TYPE with a flexible + array member named MEMBER that is followed by N bytes of other data. + This is not simply sizeof (TYPE) + N, since it may require + alignment on unusually picky C11 platforms, and + FLEXIBLE_ARRAY_MEMBER may be 1 on pre-C11 platforms. + Yield a value less than N if and only if arithmetic overflow occurs. */ + +#define FLEXSIZEOF(type, member, n) \ + ((offsetof (type, member) + FLEXALIGNOF (type) - 1 + (n)) \ + & ~ (FLEXALIGNOF (type) - 1)) |