root/maint/gnulib/lib/malloc/dynarray_resize.c

/* */

DEFINITIONS

1. __libc_dynarray_resize

   1 /* Increase the size of a dynamic array.
   2    Copyright (C) 2017-2021 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4 
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9 
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14 
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18 
  19 #ifndef _LIBC
  20 # include <libc-config.h>
  21 #endif
  22 
  23 #include <dynarray.h>
  24 #include <errno.h>
  25 #include <intprops.h>
  26 #include <stdlib.h>
  27 #include <string.h>
  28 
  29 bool
  30 __libc_dynarray_resize (struct dynarray_header *list, size_t size,
     /*  */
  31                         void *scratch, size_t element_size)
  32 {
  33   /* The existing allocation provides sufficient room.  */
  34   if (size <= list->allocated)
  35     {
  36       list->used = size;
  37       return true;
  38     }
  39 
  40   /* Otherwise, use size as the new allocation size.  The caller is
  41      expected to provide the final size of the array, so there is no
  42      over-allocation here.  */
  43 
  44   size_t new_size_bytes;
  45   if (INT_MULTIPLY_WRAPV (size, element_size, &new_size_bytes))
  46     {
  47       /* Overflow.  */
  48       __set_errno (ENOMEM);
  49       return false;
  50     }
  51   void *new_array;
  52   if (list->array == scratch)
  53     {
  54       /* The previous array was not heap-allocated.  */
  55       new_array = malloc (new_size_bytes);
  56       if (new_array != NULL && list->array != NULL)
  57         memcpy (new_array, list->array, list->used * element_size);
  58     }
  59   else
  60     new_array = realloc (list->array, new_size_bytes);
  61   if (new_array == NULL)
  62     return false;
  63   list->array = new_array;
  64   list->allocated = size;
  65   list->used = size;
  66   return true;
  67 }
  68 libc_hidden_def (__libc_dynarray_resize)

/* */