From eca49bb06a71980ef61d078904573f25890fc7f2 Mon Sep 17 00:00:00 2001
From: zautrix <zautrix>
Date: Tue, 19 Oct 2004 20:16:14 +0000
Subject: Initial revision

---
(limited to 'pwmanager/libcrypt/mpi/mpi-scan.c')

diff --git a/pwmanager/libcrypt/mpi/mpi-scan.c b/pwmanager/libcrypt/mpi/mpi-scan.c
new file mode 100644
index 0000000..90699cd
--- a/dev/null
+++ b/pwmanager/libcrypt/mpi/mpi-scan.c
@@ -0,0 +1,132 @@
+/* mpi-scan.c  -  MPI functions
+ *	Copyright (C) 1998, 2001, 2002, 2003 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"
+#include "longlong.h"
+
+/****************
+ * Scan through an mpi and return byte for byte. a -1 is returned to indicate
+ * the end of the mpi. Scanning is done from the lsb to the msb, returned
+ * values are in the range of 0 .. 255.
+ *
+ * FIXME: This code is VERY ugly!
+ */
+int
+_gcry_mpi_getbyte( gcry_mpi_t a, unsigned idx )
+{
+    int i, j;
+    unsigned n;
+    mpi_ptr_t ap;
+    mpi_limb_t limb;
+
+    ap = a->d;
+    for(n=0,i=0; i < a->nlimbs; i++ ) {
+	limb = ap[i];
+	for( j=0; j < BYTES_PER_MPI_LIMB; j++, n++ )
+	    if( n == idx )
+		return (limb >> j*8) & 0xff;
+    }
+    return -1;
+}
+
+
+/****************
+ * Put a value at position IDX into A. idx counts from lsb to msb
+ */
+void
+_gcry_mpi_putbyte( gcry_mpi_t a, unsigned idx, int xc )
+{
+    int i, j;
+    unsigned n;
+    mpi_ptr_t ap;
+    mpi_limb_t limb, c;
+
+    c = xc & 0xff;
+    ap = a->d;
+    for(n=0,i=0; i < a->alloced; i++ ) {
+	limb = ap[i];
+	for( j=0; j < BYTES_PER_MPI_LIMB; j++, n++ )
+	    if( n == idx ) {
+	      #if BYTES_PER_MPI_LIMB == 4
+		if( j == 0 )
+		    limb = (limb & 0xffffff00) | c;
+		else if( j == 1 )
+		    limb = (limb & 0xffff00ff) | (c<<8);
+		else if( j == 2 )
+		    limb = (limb & 0xff00ffff) | (c<<16);
+		else
+		    limb = (limb & 0x00ffffff) | (c<<24);
+	      #elif BYTES_PER_MPI_LIMB == 8
+		if( j == 0 )
+		    limb = (limb & 0xffffffffffffff00) | c;
+		else if( j == 1 )
+		    limb = (limb & 0xffffffffffff00ff) | (c<<8);
+		else if( j == 2 )
+		    limb = (limb & 0xffffffffff00ffff) | (c<<16);
+		else if( j == 3 )
+		    limb = (limb & 0xffffffff00ffffff) | (c<<24);
+		else if( j == 4 )
+		    limb = (limb & 0xffffff00ffffffff) | (c<<32);
+		else if( j == 5 )
+		    limb = (limb & 0xffff00ffffffffff) | (c<<40);
+		else if( j == 6 )
+		    limb = (limb & 0xff00ffffffffffff) | (c<<48);
+		else
+		    limb = (limb & 0x00ffffffffffffff) | (c<<56);
+	      #else
+		 #error please enhance this function, its ugly - i know.
+	      #endif
+		if( a->nlimbs <= i )
+		    a->nlimbs = i+1;
+		ap[i] = limb;
+		return;
+	    }
+    }
+    abort(); /* index out of range */
+}
+
+
+/****************
+ * Count the number of zerobits at the low end of A
+ */
+unsigned
+_gcry_mpi_trailing_zeros( gcry_mpi_t a )
+{
+    unsigned n, count = 0;
+
+    for(n=0; n < a->nlimbs; n++ ) {
+	if( a->d[n] ) {
+	    unsigned nn;
+	    mpi_limb_t alimb = a->d[n];
+
+	    count_trailing_zeros( nn, alimb );
+	    count += nn;
+	    break;
+	}
+	count += BITS_PER_MPI_LIMB;
+    }
+    return count;
+
+}
+
+
--
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