mpi-cmp.c 2.0 KB

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  1. /* mpi-cmp.c - MPI functions
  2. * Copyright (C) 1998, 1999 Free Software Foundation, Inc.
  3. *
  4. * This file is part of GnuPG.
  5. *
  6. * GnuPG is free software; you can redistribute it and/or modify
  7. * it under the terms of the GNU General Public License as published by
  8. * the Free Software Foundation; either version 2 of the License, or
  9. * (at your option) any later version.
  10. *
  11. * GnuPG is distributed in the hope that it will be useful,
  12. * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13. * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14. * GNU General Public License for more details.
  15. *
  16. * You should have received a copy of the GNU General Public License
  17. * along with this program; if not, write to the Free Software
  18. * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
  19. */
  20. #include "mpi-internal.h"
  21. int mpi_cmp_ui(MPI u, unsigned long v)
  22. {
  23. mpi_limb_t limb = v;
  24. mpi_normalize(u);
  25. if (!u->nlimbs && !limb)
  26. return 0;
  27. if (u->sign)
  28. return -1;
  29. if (u->nlimbs > 1)
  30. return 1;
  31. if (u->d[0] == limb)
  32. return 0;
  33. else if (u->d[0] > limb)
  34. return 1;
  35. else
  36. return -1;
  37. }
  38. EXPORT_SYMBOL_GPL(mpi_cmp_ui);
  39. static int do_mpi_cmp(MPI u, MPI v, int absmode)
  40. {
  41. mpi_size_t usize;
  42. mpi_size_t vsize;
  43. int usign;
  44. int vsign;
  45. int cmp;
  46. mpi_normalize(u);
  47. mpi_normalize(v);
  48. usize = u->nlimbs;
  49. vsize = v->nlimbs;
  50. usign = absmode ? 0 : u->sign;
  51. vsign = absmode ? 0 : v->sign;
  52. /* Compare sign bits. */
  53. if (!usign && vsign)
  54. return 1;
  55. if (usign && !vsign)
  56. return -1;
  57. /* U and V are either both positive or both negative. */
  58. if (usize != vsize && !usign && !vsign)
  59. return usize - vsize;
  60. if (usize != vsize && usign && vsign)
  61. return vsize + usize;
  62. if (!usize)
  63. return 0;
  64. cmp = mpihelp_cmp(u->d, v->d, usize);
  65. if (!cmp)
  66. return 0;
  67. if ((cmp < 0?1:0) == (usign?1:0))
  68. return 1;
  69. return -1;
  70. }
  71. int mpi_cmp(MPI u, MPI v)
  72. {
  73. return do_mpi_cmp(u, v, 0);
  74. }
  75. EXPORT_SYMBOL_GPL(mpi_cmp);
  76. int mpi_cmpabs(MPI u, MPI v)
  77. {
  78. return do_mpi_cmp(u, v, 1);
  79. }
  80. EXPORT_SYMBOL_GPL(mpi_cmpabs);