glibc/malloc/alloc_buffer_alloc_array.c
Paul Eggert 581c785bf3 Update copyright dates with scripts/update-copyrights
I used these shell commands:

../glibc/scripts/update-copyrights $PWD/../gnulib/build-aux/update-copyright
(cd ../glibc && git commit -am"[this commit message]")

and then ignored the output, which consisted lines saying "FOO: warning:
copyright statement not found" for each of 7061 files FOO.

I then removed trailing white space from math/tgmath.h,
support/tst-support-open-dev-null-range.c, and
sysdeps/x86_64/multiarch/strlen-vec.S, to work around the following
obscure pre-commit check failure diagnostics from Savannah.  I don't
know why I run into these diagnostics whereas others evidently do not.

remote: *** 912-#endif
remote: *** 913:
remote: *** 914-
remote: *** error: lines with trailing whitespace found
...
remote: *** error: sysdeps/unix/sysv/linux/statx_cp.c: trailing lines
2022-01-01 11:40:24 -08:00

47 lines
1.8 KiB
C

/* Array allocation from a fixed-size buffer.
Copyright (C) 2017-2022 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public
License as published by the Free Software Foundation; either
version 2.1 of the License, or (at your option) any later version.
The GNU C Library 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
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; if not, see
<https://www.gnu.org/licenses/>. */
#include <alloc_buffer.h>
#include <libc-pointer-arith.h>
void *
__libc_alloc_buffer_alloc_array (struct alloc_buffer *buf, size_t element_size,
size_t align, size_t count)
{
size_t current = buf->__alloc_buffer_current;
/* The caller asserts that align is a power of two. */
size_t aligned = ALIGN_UP (current, align);
size_t size;
bool overflow = __builtin_mul_overflow (element_size, count, &size);
size_t new_current = aligned + size;
if (!overflow /* Multiplication did not overflow. */
&& aligned >= current /* No overflow in align step. */
&& new_current >= size /* No overflow in size computation. */
&& new_current <= buf->__alloc_buffer_end) /* Room in buffer. */
{
buf->__alloc_buffer_current = new_current;
return (void *) aligned;
}
else
{
alloc_buffer_mark_failed (buf);
return NULL;
}
}
libc_hidden_def (__libc_alloc_buffer_alloc_array)