| /* mpihelp-sub.c - MPI helper functions |
| * Copyright (C) 1994, 1996 Free Software Foundation, Inc. |
| * 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 |
| * |
| * Note: This code is heavily based on the GNU MP Library. |
| * Actually it's the same code with only minor changes in the |
| * way the data is stored; this is to support the abstraction |
| * of an optional secure memory allocation which may be used |
| * to avoid revealing of sensitive data due to paging etc. |
| * The GNU MP Library itself is published under the LGPL; |
| * however I decided to publish this code under the plain GPL. |
| */ |
| |
| #include "mpi-internal.h" |
| |
| /**************** |
| * Compare OP1_PTR/OP1_SIZE with OP2_PTR/OP2_SIZE. |
| * There are no restrictions on the relative sizes of |
| * the two arguments. |
| * Return 1 if OP1 > OP2, 0 if they are equal, and -1 if OP1 < OP2. |
| */ |
| int mpihelp_cmp(mpi_ptr_t op1_ptr, mpi_ptr_t op2_ptr, mpi_size_t size) |
| { |
| mpi_size_t i; |
| mpi_limb_t op1_word, op2_word; |
| |
| for (i = size - 1; i >= 0; i--) { |
| op1_word = op1_ptr[i]; |
| op2_word = op2_ptr[i]; |
| if (op1_word != op2_word) |
| goto diff; |
| } |
| return 0; |
| |
| diff: |
| /* This can *not* be simplified to |
| * op2_word - op2_word |
| * since that expression might give signed overflow. */ |
| return (op1_word > op2_word) ? 1 : -1; |
| } |