30891f35fa
We stopped adding "Contributed by" or similar lines in sources in 2012 in favour of git logs and keeping the Contributors section of the glibc manual up to date. Removing these lines makes the license header a bit more consistent across files and also removes the possibility of error in attribution when license blocks or files are copied across since the contributed-by lines don't actually reflect reality in those cases. Move all "Contributed by" and similar lines (Written by, Test by, etc.) into a new file CONTRIBUTED-BY to retain record of these contributions. These contributors are also mentioned in manual/contrib.texi, so we just maintain this additional record as a courtesy to the earlier developers. The following scripts were used to filter a list of files to edit in place and to clean up the CONTRIBUTED-BY file respectively. These were not added to the glibc sources because they're not expected to be of any use in future given that this is a one time task: https://gist.github.com/siddhesh/b5ecac94eabfd72ed2916d6d8157e7dc https://gist.github.com/siddhesh/15ea1f5e435ace9774f485030695ee02 Reviewed-by: Carlos O'Donell <carlos@redhat.com>
60 lines
2.5 KiB
C
60 lines
2.5 KiB
C
/* Sizes of structs with flexible array members.
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Copyright 2016-2021 Free Software Foundation, Inc.
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This file is part of the GNU C Library.
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The GNU C Library is free software; you can redistribute it and/or
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modify it under the terms of the GNU Lesser General Public
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License as published by the Free Software Foundation; either
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version 2.1 of the License, or (at your option) any later version.
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The GNU C Library is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public
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License along with the GNU C Library; if not, see
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<https://www.gnu.org/licenses/>. */
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#include <stddef.h>
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/* Nonzero multiple of alignment of TYPE, suitable for FLEXSIZEOF below.
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On older platforms without _Alignof, use a pessimistic bound that is
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safe in practice even if FLEXIBLE_ARRAY_MEMBER is 1.
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On newer platforms, use _Alignof to get a tighter bound. */
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#if !defined __STDC_VERSION__ || __STDC_VERSION__ < 201112
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# define FLEXALIGNOF(type) (sizeof (type) & ~ (sizeof (type) - 1))
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#else
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# define FLEXALIGNOF(type) _Alignof (type)
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#endif
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/* Yield a properly aligned upper bound on the size of a struct of
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type TYPE with a flexible array member named MEMBER that is
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followed by N bytes of other data. The result is suitable as an
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argument to malloc. For example:
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struct s { int n; char d[FLEXIBLE_ARRAY_MEMBER]; };
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struct s *p = malloc (FLEXSIZEOF (struct s, d, n * sizeof (char)));
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FLEXSIZEOF (TYPE, MEMBER, N) is not simply (sizeof (TYPE) + N),
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since FLEXIBLE_ARRAY_MEMBER may be 1 on pre-C11 platforms. Nor is
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it simply (offsetof (TYPE, MEMBER) + N), as that might yield a size
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that causes malloc to yield a pointer that is not properly aligned
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for TYPE; for example, if sizeof (int) == alignof (int) == 4,
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malloc (offsetof (struct s, d) + 3 * sizeof (char)) is equivalent
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to malloc (7) and might yield a pointer that is not a multiple of 4
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(which means the pointer is not properly aligned for struct s),
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whereas malloc (FLEXSIZEOF (struct s, d, 3 * sizeof (char))) is
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equivalent to malloc (8) and must yield a pointer that is a
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multiple of 4.
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Yield a value less than N if and only if arithmetic overflow occurs. */
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#define FLEXSIZEOF(type, member, n) \
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((offsetof (type, member) + FLEXALIGNOF (type) - 1 + (n)) \
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& ~ (FLEXALIGNOF (type) - 1))
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