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author | James Morris <jmorris@namei.org> | 2012-01-09 05:16:48 +0400 |
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committer | James Morris <jmorris@namei.org> | 2012-01-09 05:16:48 +0400 |
commit | 8fcc99549522fc7a0bbaeb5755855ab0d9a59ce8 (patch) | |
tree | a118eaef15d4ba22247f45ee01537ecc906cd161 /lib/mpi/mpi-gcd.c | |
parent | 805a6af8dba5dfdd35ec35dc52ec0122400b2610 (diff) | |
parent | 7b7e5916aa2f46e57f8bd8cb89c34620ebfda5da (diff) | |
download | linux-8fcc99549522fc7a0bbaeb5755855ab0d9a59ce8.tar.xz |
Merge branch 'next' into for-linus
Conflicts:
security/integrity/evm/evm_crypto.c
Resolved upstream fix vs. next conflict manually.
Signed-off-by: James Morris <jmorris@namei.org>
Diffstat (limited to 'lib/mpi/mpi-gcd.c')
-rw-r--r-- | lib/mpi/mpi-gcd.c | 59 |
1 files changed, 59 insertions, 0 deletions
diff --git a/lib/mpi/mpi-gcd.c b/lib/mpi/mpi-gcd.c new file mode 100644 index 000000000000..13c48aef9c4e --- /dev/null +++ b/lib/mpi/mpi-gcd.c @@ -0,0 +1,59 @@ +/* mpi-gcd.c - MPI functions + * Copyright (C) 1998, 1999, 2000, 2001 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" + +/**************** + * Find the greatest common divisor G of A and B. + * Return: true if this 1, false in all other cases + */ +int mpi_gcd(MPI g, const MPI xa, const MPI xb) +{ + MPI a = NULL, b = NULL; + + if (mpi_copy(&a, xa) < 0) + goto nomem; + + if (mpi_copy(&b, xb) < 0) + goto nomem; + + /* TAOCP Vol II, 4.5.2, Algorithm A */ + a->sign = 0; + b->sign = 0; + while (mpi_cmp_ui(b, 0)) { + if (mpi_fdiv_r(g, a, b) < 0) /* g used as temorary variable */ + goto nomem; + if (mpi_set(a, b) < 0) + goto nomem; + if (mpi_set(b, g) < 0) + goto nomem; + } + if (mpi_set(g, a) < 0) + goto nomem; + + mpi_free(a); + mpi_free(b); + return !mpi_cmp_ui(g, 1); + +nomem: + mpi_free(a); + mpi_free(b); + return -ENOMEM; +} |