hash_log2.c 2.3 KB

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  1. /*-
  2. * Copyright (c) 1990, 1993, 1994
  3. * The Regents of the University of California. All rights reserved.
  4. *
  5. * This code is derived from software contributed to Berkeley by
  6. * Margo Seltzer.
  7. *
  8. * Redistribution and use in source and binary forms, with or without
  9. * modification, are permitted provided that the following conditions
  10. * are met:
  11. * 1. Redistributions of source code must retain the above copyright
  12. * notice, this list of conditions and the following disclaimer.
  13. * 2. Redistributions in binary form must reproduce the above copyright
  14. * notice, this list of conditions and the following disclaimer in the
  15. * documentation and/or other materials provided with the distribution.
  16. * 3. All advertising materials mentioning features or use of this software
  17. * must display the following acknowledgement:
  18. * This product includes software developed by the University of
  19. * California, Berkeley and its contributors.
  20. * 4. Neither the name of the University nor the names of its contributors
  21. * may be used to endorse or promote products derived from this software
  22. * without specific prior written permission.
  23. *
  24. * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
  25. * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  26. * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  27. * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
  28. * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  29. * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  30. * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  31. * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  32. * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  33. * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  34. * SUCH DAMAGE.
  35. */
  36. #if defined(LIBC_SCCS) && !defined(lint)
  37. static char sccsid[] = "@(#)hash_log2.c 8.2 (Berkeley) 5/31/94";
  38. #endif /* LIBC_SCCS and not lint */
  39. #include <sys/types.h>
  40. #include "../include/db.h"
  41. u_int32_t __hash_log2 __P((u_int32_t));
  42. u_int32_t
  43. __hash_log2(num)
  44. u_int32_t num;
  45. {
  46. register u_int32_t i, limit;
  47. limit = 1;
  48. for (i = 0; limit < num; limit = limit << 1, i++);
  49. return (i);
  50. }