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Diffstat (limited to '')
-rw-r--r-- | lib/malloc/dynarray_resize.c | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/lib/malloc/dynarray_resize.c b/lib/malloc/dynarray_resize.c new file mode 100644 index 0000000..8d1922e --- /dev/null +++ b/lib/malloc/dynarray_resize.c @@ -0,0 +1,68 @@ +/* Increase the size of a dynamic array. + 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/>. */ + +#ifndef _LIBC +# include <libc-config.h> +#endif + +#include <dynarray.h> +#include <errno.h> +#include <intprops.h> +#include <stdlib.h> +#include <string.h> + +bool +__libc_dynarray_resize (struct dynarray_header *list, size_t size, + void *scratch, size_t element_size) +{ + /* The existing allocation provides sufficient room. */ + if (size <= list->allocated) + { + list->used = size; + return true; + } + + /* Otherwise, use size as the new allocation size. The caller is + expected to provide the final size of the array, so there is no + over-allocation here. */ + + size_t new_size_bytes; + if (INT_MULTIPLY_WRAPV (size, element_size, &new_size_bytes)) + { + /* Overflow. */ + __set_errno (ENOMEM); + return false; + } + void *new_array; + if (list->array == scratch) + { + /* The previous array was not heap-allocated. */ + new_array = malloc (new_size_bytes); + if (new_array != NULL && list->array != NULL) + memcpy (new_array, list->array, list->used * element_size); + } + else + new_array = realloc (list->array, new_size_bytes); + if (new_array == NULL) + return false; + list->array = new_array; + list->allocated = size; + list->used = size; + return true; +} +libc_hidden_def (__libc_dynarray_resize) |