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reallocarray.c (1306B)

      1 /*
      2  * Copyright (c) 2008 Otto Moerbeek <otto@drijf.net>
      3  *
      4  * Permission to use, copy, modify, and distribute this software for any
      5  * purpose with or without fee is hereby granted, provided that the above
      6  * copyright notice and this permission notice appear in all copies.
      7  *
      8  * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
      9  * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
     10  * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
     11  * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
     12  * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN
     13  * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF
     14  * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
     15  */
     16 
     17 #include <sys/types.h>
     18 #include <errno.h>
     19 #include <stdint.h>
     20 #include <stdlib.h>
     21 
     22 #include "compat.h"
     23 
     24 /*
     25  * This is sqrt(SIZE_MAX+1), as s1*s2 <= SIZE_MAX
     26  * if both s1 < MUL_NO_OVERFLOW and s2 < MUL_NO_OVERFLOW
     27  */
     28 #define MUL_NO_OVERFLOW	(1UL << (sizeof(size_t) * 4))
     29 
     30 void *
     31 reallocarray(void *optr, size_t nmemb, size_t size)
     32 {
     33 	if ((nmemb >= MUL_NO_OVERFLOW || size >= MUL_NO_OVERFLOW) &&
     34 	    nmemb > 0 && SIZE_MAX / nmemb < size) {
     35 		errno = ENOMEM;
     36 		return NULL;
     37 	}
     38 	return realloc(optr, size * nmemb);
     39 }