diff options
Diffstat (limited to 'libotr/libgcrypt-1.8.7/mpi/mpi-cmp.c')
-rw-r--r-- | libotr/libgcrypt-1.8.7/mpi/mpi-cmp.c | 130 |
1 files changed, 130 insertions, 0 deletions
diff --git a/libotr/libgcrypt-1.8.7/mpi/mpi-cmp.c b/libotr/libgcrypt-1.8.7/mpi/mpi-cmp.c new file mode 100644 index 0000000..8927fa0 --- /dev/null +++ b/libotr/libgcrypt-1.8.7/mpi/mpi-cmp.c @@ -0,0 +1,130 @@ +/* mpi-cmp.c - MPI functions + * Copyright (C) 1998, 1999, 2001, 2002, 2005 Free Software Foundation, Inc. + * + * This file is part of Libgcrypt. + * + * Libgcrypt is free software; you can redistribute it and/or modify + * it under the terms of the GNU Lesser General Public License as + * published by the Free Software Foundation; either version 2.1 of + * the License, or (at your option) any later version. + * + * Libgcrypt 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 Lesser General Public License for more details. + * + * You should have received a copy of the GNU Lesser 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 <config.h> +#include <stdio.h> +#include <stdlib.h> +#include "mpi-internal.h" + +int +_gcry_mpi_cmp_ui (gcry_mpi_t u, unsigned long v) +{ + mpi_limb_t limb = v; + + _gcry_mpi_normalize (u); + + /* Handle the case that U contains no limb. */ + if (u->nlimbs == 0) + return -(limb != 0); + + /* Handle the case that U is negative. */ + if (u->sign) + return -1; + + if (u->nlimbs == 1) + { + /* Handle the case that U contains exactly one limb. */ + + if (u->d[0] > limb) + return 1; + if (u->d[0] < limb) + return -1; + return 0; + } + else + /* Handle the case that U contains more than one limb. */ + return 1; +} + + +/* Helper for _gcry_mpi_cmp and _gcry_mpi_cmpabs. */ +static int +do_mpi_cmp (gcry_mpi_t u, gcry_mpi_t v, int absmode) +{ + mpi_size_t usize; + mpi_size_t vsize; + int usign; + int vsign; + int cmp; + + if (mpi_is_opaque (u) || mpi_is_opaque (v)) + { + /* We have no signan and thus ABSMODE has no efeect here. */ + if (mpi_is_opaque (u) && !mpi_is_opaque (v)) + return -1; + if (!mpi_is_opaque (u) && mpi_is_opaque (v)) + return 1; + if (!u->sign && !v->sign) + return 0; /* Empty buffers are identical. */ + if (u->sign < v->sign) + return -1; + if (u->sign > v->sign) + return 1; + return memcmp (u->d, v->d, (u->sign+7)/8); + } + else + { + _gcry_mpi_normalize (u); + _gcry_mpi_normalize (v); + + usize = u->nlimbs; + vsize = v->nlimbs; + usign = absmode? 0 : u->sign; + vsign = absmode? 0 : v->sign; + + /* Special treatment for +0 == -0 */ + if (!usize && !vsize) + return 0; + + /* 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; + if (!(cmp = _gcry_mpih_cmp (u->d, v->d, usize))) + return 0; + if ((cmp < 0?1:0) == (usign?1:0)) + return 1; + } + return -1; +} + + +int +_gcry_mpi_cmp (gcry_mpi_t u, gcry_mpi_t v) +{ + return do_mpi_cmp (u, v, 0); +} + +/* Compare only the absolute values. */ +int +_gcry_mpi_cmpabs (gcry_mpi_t u, gcry_mpi_t v) +{ + return do_mpi_cmp (u, v, 1); +} |