diff options
Diffstat (limited to 'lib/mpi/mpi-cmp.c')
-rw-r--r-- | lib/mpi/mpi-cmp.c | 98 |
1 files changed, 98 insertions, 0 deletions
diff --git a/lib/mpi/mpi-cmp.c b/lib/mpi/mpi-cmp.c new file mode 100644 index 000000000..0835b6213 --- /dev/null +++ b/lib/mpi/mpi-cmp.c @@ -0,0 +1,98 @@ +/* mpi-cmp.c - MPI functions + * Copyright (C) 1998, 1999 Free Software Foundation, Inc. + * + * This file is part of GnuPG. + * + * GnuPG is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * GnuPG is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA + */ + +#include "mpi-internal.h" + +int mpi_cmp_ui(MPI u, unsigned long v) +{ + mpi_limb_t limb = v; + + mpi_normalize(u); + if (u->nlimbs == 0) { + if (v == 0) + return 0; + else + return -1; + } + if (u->sign) + return -1; + if (u->nlimbs > 1) + return 1; + + if (u->d[0] == limb) + return 0; + else if (u->d[0] > limb) + return 1; + else + return -1; +} +EXPORT_SYMBOL_GPL(mpi_cmp_ui); + +static int do_mpi_cmp(MPI u, MPI v, int absmode) +{ + mpi_size_t usize; + mpi_size_t vsize; + int usign; + int vsign; + int cmp; + + mpi_normalize(u); + mpi_normalize(v); + + usize = u->nlimbs; + vsize = v->nlimbs; + usign = absmode ? 0 : u->sign; + vsign = absmode ? 0 : v->sign; + + /* Compare sign bits. */ + + if (!usign && vsign) + return 1; + if (usign && !vsign) + return -1; + + /* U and V are either both positive or both negative. */ + + if (usize != vsize && !usign && !vsign) + return usize - vsize; + if (usize != vsize && usign && vsign) + return vsize + usize; + if (!usize) + return 0; + cmp = mpihelp_cmp(u->d, v->d, usize); + if (!cmp) + return 0; + if ((cmp < 0?1:0) == (usign?1:0)) + return 1; + + return -1; +} + +int mpi_cmp(MPI u, MPI v) +{ + return do_mpi_cmp(u, v, 0); +} +EXPORT_SYMBOL_GPL(mpi_cmp); + +int mpi_cmpabs(MPI u, MPI v) +{ + return do_mpi_cmp(u, v, 1); +} +EXPORT_SYMBOL_GPL(mpi_cmpabs); |