stagit

 /*
  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
  *
  * Permission to use, copy, modify, and distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
  * copyright notice and this permission notice appear in all copies.
  *
  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
  */
 
 #include <sys/types.h>
 #include <errno.h>
 #include <stdint.h>
 #include <stdlib.h>
 
 #include "compat.h"
 
 /*
  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
  */
 #define MUL_NO_OVERFLOW	(1UL << (sizeof(size_t) * 4))
 
 void *
 reallocarray(void *optr, size_t nmemb, size_t size)
 {
 	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
 	    nmemb > 0 && SIZE_MAX / nmemb < size) {
 		errno = ENOMEM;
 		return NULL;
 	}
 	return realloc(optr, size * nmemb);
 }