1 files changed, 63 insertions, 0 deletions
diff --git a/mpi/mpih-cmp.c b/mpi/mpih-cmp.c
new file mode 100644
index 0000000..4c12c71
--- /dev/null
+++ b/mpi/mpih-cmp.c
@@ -0,0 +1,63 @@
+/* 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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
+ * 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 <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#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;
+}
+