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 21 #include "mpi-internal.h" 22 23 int mpi_cmp_ui(MPI u, unsigned long v) 24 { 25 mpi_limb_t limb = v; 26 27 mpi_normalize(u); 28 if (u->nlimbs == 0) { 29 if (v == 0) 30 return 0; 31 else 32 return -1; 33 } 34 if (u->sign) 35 return -1; 36 if (u->nlimbs > 1) 37 return 1; 38 39 if (u->d[0] == limb) 40 return 0; 41 else if (u->d[0] > limb) 42 return 1; 43 else 44 return -1; 45 } 46 EXPORT_SYMBOL_GPL(mpi_cmp_ui); 47 48 static int do_mpi_cmp(MPI u, MPI v, int absmode) 49 { 50 mpi_size_t usize; 51 mpi_size_t vsize; 52 int usign; 53 int vsign; 54 int cmp; 55 56 mpi_normalize(u); 57 mpi_normalize(v); 58 59 usize = u->nlimbs; 60 vsize = v->nlimbs; 61 usign = absmode ? 0 : u->sign; 62 vsign = absmode ? 0 : v->sign; 63 64 /* Compare sign bits. */ 65 66 if (!usign && vsign) 67 return 1; 68 if (usign && !vsign) 69 return -1; 70 71 /* U and V are either both positive or both negative. */ 72 73 if (usize != vsize && !usign && !vsign) 74 return usize - vsize; 75 if (usize != vsize && usign && vsign) 76 return vsize + usize; 77 if (!usize) 78 return 0; 79 cmp = mpihelp_cmp(u->d, v->d, usize); 80 if (!cmp) 81 return 0; 82 if ((cmp < 0?1:0) == (usign?1:0)) 83 return 1; 84 85 return -1; 86 } 87 88 int mpi_cmp(MPI u, MPI v) 89 { 90 return do_mpi_cmp(u, v, 0); 91 } 92 EXPORT_SYMBOL_GPL(mpi_cmp); 93 94 int mpi_cmpabs(MPI u, MPI v) 95 { 96 return do_mpi_cmp(u, v, 1); 97 } 98 EXPORT_SYMBOL_GPL(mpi_cmpabs); 99