lib/calloc.c

   1 /* calloc() function that is glibc compatible.
   2    This wrapper function is required at least on Tru64 UNIX 5.1 and mingw.
   3    Copyright (C) 2004-2007, 2009-2020 Free Software Foundation, Inc.
   4
   5    This program is free software: you can redistribute it and/or modify
   6    it under the terms of the GNU General Public License as published by
   7    the Free Software Foundation; either version 3 of the License, or
   8    (at your option) any later version.
   9
  10    This program 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
  13    GNU General Public License for more details.
  14
  15    You should have received a copy of the GNU General Public License
  16    along with this program.  If not, see <https://www.gnu.org/licenses/>.  */
  17
  18 /* written by Jim Meyering and Bruno Haible */
  19
  20 #include <config.h>
  21 /* Only the AC_FUNC_CALLOC macro defines 'calloc' already in config.h.  */
  22 #ifdef calloc
  23 # define NEED_CALLOC_GNU 1
  24 # undef calloc
  25 /* Whereas the gnulib module 'calloc-gnu' defines HAVE_CALLOC_GNU.  */
  26 #elif GNULIB_CALLOC_GNU && !HAVE_CALLOC_GNU
  27 # define NEED_CALLOC_GNU 1
  28 #endif
  29
  30 /* Specification.  */
  31 #include <stdlib.h>
  32
  33 #include <errno.h>
  34
  35 /* Call the system's calloc below.  */
  36 #undef calloc
  37
  38 /* Allocate and zero-fill an NxS-byte block of memory from the heap.
  39    If N or S is zero, allocate and zero-fill a 1-byte block.  */
  40
  41 void *
  42 rpl_calloc (size_t n, size_t s)
  43 {
  44   void *result;
  45
  46 #if NEED_CALLOC_GNU
  47   if (n == 0 || s == 0)
  48     {
  49       n = 1;
  50       s = 1;
  51     }
  52   else
  53     {
  54       /* Defend against buggy calloc implementations that mishandle
  55          size_t overflow.  */
  56       size_t bytes = n * s;
  57       if (bytes / s != n)
  58         {
  59           errno = ENOMEM;
  60           return NULL;
  61         }
  62     }
  63 #endif
  64
  65   result = calloc (n, s);
  66
  67 #if !HAVE_CALLOC_POSIX
  68   if (result == NULL)
  69     errno = ENOMEM;
  70 #endif
  71
  72   return result;
  73 }