diff options
Diffstat (limited to 'malloc/alloc_buffer_alloc_array.c')
| -rw-r--r-- | malloc/alloc_buffer_alloc_array.c | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/malloc/alloc_buffer_alloc_array.c b/malloc/alloc_buffer_alloc_array.c new file mode 100644 index 0000000000..68e14da8dd --- /dev/null +++ b/malloc/alloc_buffer_alloc_array.c @@ -0,0 +1,47 @@ +/* Array allocation from a fixed-size buffer. + Copyright (C) 2017 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 + <http://www.gnu.org/licenses/>. */ + +#include <alloc_buffer.h> +#include <malloc-internal.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 = check_mul_overflow_size_t (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) |