memcmp.c 2.2 KB

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  1. /* $OpenBSD: memcmp.c,v 1.6 2015/08/31 02:53:57 guenther Exp $ */
  2. /*-
  3. * Copyright (c) 1990 The Regents of the University of California.
  4. * All rights reserved.
  5. *
  6. * This code is derived from software contributed to Berkeley by
  7. * Chris Torek.
  8. *
  9. * Redistribution and use in source and binary forms, with or without
  10. * modification, are permitted provided that the following conditions
  11. * are met:
  12. * 1. Redistributions of source code must retain the above copyright
  13. * notice, this list of conditions and the following disclaimer.
  14. * 2. Redistributions in binary form must reproduce the above copyright
  15. * notice, this list of conditions and the following disclaimer in the
  16. * documentation and/or other materials provided with the distribution.
  17. * 3. Neither the name of the University nor the names of its contributors
  18. * may be used to endorse or promote products derived from this software
  19. * without specific prior written permission.
  20. *
  21. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  22. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  23. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  24. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  25. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  26. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  27. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  28. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  29. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  30. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  31. * SUCH DAMAGE.
  32. */
  33. #include <string.h>
  34. /*
  35. * Compare memory regions.
  36. */
  37. int
  38. __memcmp(const void *s1, const void *s2, size_t n)
  39. {
  40. if (n != 0) {
  41. const unsigned char *p1 = (const unsigned char *)s1;
  42. const unsigned char *p2 = (const unsigned char *)s2;
  43. do {
  44. if (*p1++ != *p2++)
  45. return (*--p1 - *--p2);
  46. } while (--n != 0);
  47. }
  48. return (0);
  49. }
  50. int
  51. memcmp(const void *s1, const void *s2, size_t n)
  52. {
  53. return __memcmp(s1, s2, n);
  54. }