/security/nss/lib/freebl/mpi/utils/invmod.c

http://github.com/zpao/v8monkey · C · 92 lines · 39 code · 12 blank · 41 comment · 3 complexity · 9fe97199def669151e9b6a355f38d25d MD5 · raw file

  1. /*
  2. * invmod.c
  3. *
  4. * Compute modular inverses
  5. *
  6. * ***** BEGIN LICENSE BLOCK *****
  7. * Version: MPL 1.1/GPL 2.0/LGPL 2.1
  8. *
  9. * The contents of this file are subject to the Mozilla Public License Version
  10. * 1.1 (the "License"); you may not use this file except in compliance with
  11. * the License. You may obtain a copy of the License at
  12. * http://www.mozilla.org/MPL/
  13. *
  14. * Software distributed under the License is distributed on an "AS IS" basis,
  15. * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
  16. * for the specific language governing rights and limitations under the
  17. * License.
  18. *
  19. * The Original Code is the MPI Arbitrary Precision Integer Arithmetic library.
  20. *
  21. * The Initial Developer of the Original Code is
  22. * Michael J. Fromberger.
  23. * Portions created by the Initial Developer are Copyright (C) 1997
  24. * the Initial Developer. All Rights Reserved.
  25. *
  26. * Contributor(s):
  27. *
  28. * Alternatively, the contents of this file may be used under the terms of
  29. * either the GNU General Public License Version 2 or later (the "GPL"), or
  30. * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
  31. * in which case the provisions of the GPL or the LGPL are applicable instead
  32. * of those above. If you wish to allow use of your version of this file only
  33. * under the terms of either the GPL or the LGPL, and not to allow others to
  34. * use your version of this file under the terms of the MPL, indicate your
  35. * decision by deleting the provisions above and replace them with the notice
  36. * and other provisions required by the GPL or the LGPL. If you do not delete
  37. * the provisions above, a recipient may use your version of this file under
  38. * the terms of any one of the MPL, the GPL or the LGPL.
  39. *
  40. * ***** END LICENSE BLOCK ***** */
  41. /* $Id: invmod.c,v 1.3 2004/04/27 23:04:37 gerv%gerv.net Exp $ */
  42. #include <stdio.h>
  43. #include <stdlib.h>
  44. #include "mpi.h"
  45. int main(int argc, char *argv[])
  46. {
  47. mp_int a, m;
  48. mp_err res;
  49. char *buf;
  50. int len, out = 0;
  51. if(argc < 3) {
  52. fprintf(stderr, "Usage: %s <a> <m>\n", argv[0]);
  53. return 1;
  54. }
  55. mp_init(&a); mp_init(&m);
  56. mp_read_radix(&a, argv[1], 10);
  57. mp_read_radix(&m, argv[2], 10);
  58. if(mp_cmp(&a, &m) > 0)
  59. mp_mod(&a, &m, &a);
  60. switch((res = mp_invmod(&a, &m, &a))) {
  61. case MP_OKAY:
  62. len = mp_radix_size(&a, 10);
  63. buf = malloc(len);
  64. mp_toradix(&a, buf, 10);
  65. printf("%s\n", buf);
  66. free(buf);
  67. break;
  68. case MP_UNDEF:
  69. printf("No inverse\n");
  70. out = 1;
  71. break;
  72. default:
  73. printf("error: %s (%d)\n", mp_strerror(res), res);
  74. out = 2;
  75. break;
  76. }
  77. mp_clear(&a);
  78. mp_clear(&m);
  79. return out;
  80. }