108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
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/* mpi-cmp.c - MPI functions
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* Copyright (C) 1998, 1999, 2001, 2002, 2005 Free Software Foundation, Inc.
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*
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* This file is part of Libgcrypt.
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*
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* Libgcrypt is free software; you can redistribute it and/or modify
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* it under the terms of the GNU Lesser General Public License as
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* published by the Free Software Foundation; either version 2.1 of
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* the License, or (at your option) any later version.
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*
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* Libgcrypt is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
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*/
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#include <config.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include "mpi-internal.h"
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int
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gcry_mpi_cmp_ui (gcry_mpi_t u, unsigned long v)
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{
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mpi_limb_t limb = v;
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_gcry_mpi_normalize (u);
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/* Handle the case that U contains no limb. */
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if (u->nlimbs == 0)
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return -(limb != 0);
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/* Handle the case that U is negative. */
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if (u->sign)
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return -1;
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if (u->nlimbs == 1)
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{
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/* Handle the case that U contains exactly one limb. */
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if (u->d[0] > limb)
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return 1;
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if (u->d[0] < limb)
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return -1;
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return 0;
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}
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else
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/* Handle the case that U contains more than one limb. */
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return 1;
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}
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int
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gcry_mpi_cmp (gcry_mpi_t u, gcry_mpi_t v)
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{
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mpi_size_t usize;
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mpi_size_t vsize;
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int cmp;
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if (mpi_is_opaque (u) || mpi_is_opaque (v))
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{
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if (mpi_is_opaque (u) && !mpi_is_opaque (v))
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return -1;
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if (!mpi_is_opaque (u) && mpi_is_opaque (v))
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return 1;
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if (!u->sign && !v->sign)
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return 0; /* Empty buffers are identical. */
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if (u->sign < v->sign)
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return -1;
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if (u->sign > v->sign)
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return 1;
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return memcmp (u->d, v->d, (u->sign+7)/8);
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}
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else
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{
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_gcry_mpi_normalize (u);
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_gcry_mpi_normalize (v);
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usize = u->nlimbs;
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vsize = v->nlimbs;
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/* Compare sign bits. */
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if (!u->sign && v->sign)
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return 1;
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if (u->sign && !v->sign)
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return -1;
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/* U and V are either both positive or both negative. */
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if (usize != vsize && !u->sign && !v->sign)
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return usize - vsize;
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if (usize != vsize && u->sign && v->sign)
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return vsize + usize;
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if (!usize )
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return 0;
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if (!(cmp = _gcry_mpih_cmp (u->d, v->d, usize)))
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return 0;
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if ((cmp < 0?1:0) == (u->sign?1:0))
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return 1;
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}
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return -1;
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}
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