linux/lib/mpi/mpi-cmp.c
Dmitry Kasatkin 7e8dec918e crypto: GnuPG based MPI lib - additional sources (part 4)
Adds the multi-precision-integer maths library which was originally taken
from GnuPG and ported to the kernel by (among others) David Howells.
This version is taken from Fedora kernel 2.6.32-71.14.1.el6.
The difference is that checkpatch reported errors and warnings have been fixed.

This library is used to implemenet RSA digital signature verification
used in IMA/EVM integrity protection subsystem.

Due to patch size limitation, the patch is divided into 4 parts.

This code is unnecessary for RSA digital signature verification,
but for completeness it is included here and can be compiled,
if CONFIG_MPILIB_EXTRA is enabled.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
2011-11-09 11:47:26 +02:00

69 lines
1.6 KiB
C

/* 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 && !limb)
return 0;
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;
}
int mpi_cmp(MPI u, MPI v)
{
mpi_size_t usize, vsize;
int cmp;
mpi_normalize(u);
mpi_normalize(v);
usize = u->nlimbs;
vsize = v->nlimbs;
if (!u->sign && v->sign)
return 1;
if (u->sign && !v->sign)
return -1;
if (usize != vsize && !u->sign && !v->sign)
return usize - vsize;
if (usize != vsize && u->sign && v->sign)
return vsize + usize;
if (!usize)
return 0;
cmp = mpihelp_cmp(u->d, v->d, usize);
if (!cmp)
return 0;
if ((cmp < 0 ? 1 : 0) == (u->sign ? 1 : 0))
return 1;
return -1;
}