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Add internal facility for dynamic array handling

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This is intended as a type-safe alternative to obstacks and
hand-written realloc constructs.  The implementation avoids
writing function pointers to the heap.
This commit is contained in:
Florian Weimer
2017-06-02 11:59:28 +02:00
parent 09103e4025
commit 91b6eb1140
21 changed files with 2538 additions and 2 deletions
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59
malloc/dynarray_resize.c Normal file
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/* Increase the size of a dynamic array.
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 <dynarray.h>
#include <malloc-internal.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 (check_mul_overflow_size_t (size, element_size, &new_size_bytes))
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)