diff options
Diffstat (limited to 'gl/lib/malloc/dynarray_emplace_enlarge.c')
-rw-r--r-- | gl/lib/malloc/dynarray_emplace_enlarge.c | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/gl/lib/malloc/dynarray_emplace_enlarge.c b/gl/lib/malloc/dynarray_emplace_enlarge.c new file mode 100644 index 0000000..65aabb1 --- /dev/null +++ b/gl/lib/malloc/dynarray_emplace_enlarge.c @@ -0,0 +1,77 @@ +/* Increase the size of a dynamic array in preparation of an emplace operation. + Copyright (C) 2017-2023 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 <stdckdint.h> +#include <stdlib.h> +#include <string.h> + +bool +__libc_dynarray_emplace_enlarge (struct dynarray_header *list, + void *scratch, size_t element_size) +{ + size_t new_allocated; + if (list->allocated == 0) + { + /* No scratch buffer provided. Choose a reasonable default + size. */ + if (element_size < 4) + new_allocated = 16; + else if (element_size < 8) + new_allocated = 8; + else + new_allocated = 4; + } + else + /* Increase the allocated size, using an exponential growth + policy. */ + { + new_allocated = list->allocated + list->allocated / 2 + 1; + if (new_allocated <= list->allocated) + { + /* Overflow. */ + __set_errno (ENOMEM); + return false; + } + } + + size_t new_size; + if (ckd_mul (&new_size, new_allocated, element_size)) + return false; + void *new_array; + if (list->array == scratch) + { + /* The previous array was not heap-allocated. */ + new_array = malloc (new_size); + if (new_array != NULL && list->array != NULL) + memcpy (new_array, list->array, list->used * element_size); + } + else + new_array = realloc (list->array, new_size); + if (new_array == NULL) + return false; + list->array = new_array; + list->allocated = new_allocated; + return true; +} +libc_hidden_def (__libc_dynarray_emplace_enlarge) |