initially checkin

1 files changed, 133 insertions, 0 deletions

diff --git a/mpi/mpi-bit.c b/mpi/mpi-bit.c
new file mode 100644
index 000000000..9cb346aa4
--- /dev/null
+++ b/mpi/mpi-bit.c
@@ -0,0 +1,133 @@
+/* mpi-bit.c  -  MPI bit level fucntions
+ *	Copyright (c) 1997 by Werner Koch (dd9jn)
+ *
+ * This file is part of G10.
+ *
+ * G10 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.
+ *
+ * G10 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 <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "mpi-internal.h"
+
+
+/****************
+ * Return the number of bits in A.
+ * fixme: we should not count leading zero bits
+ */
+unsigned
+mpi_get_nbits( MPI a )
+{
+    return a->nlimbs * BITS_PER_MPI_LIMB;
+}
+
+
+/****************
+ * Test wether bit N is set.
+ */
+int
+mpi_test_bit( MPI a, unsigned n )
+{
+    unsigned limbno, bitno;
+    mpi_limb_t limb;
+
+    limbno = n / BITS_PER_MPI_LIMB;
+    bitno  = n % BITS_PER_MPI_LIMB;
+
+    if( limbno >= a->nlimbs )
+	return 0; /* too far left: this is a 0 */
+    limb = a->d[limbno];
+    return (limb & (1 << bitno))? 1: 0;
+}
+
+
+/****************
+ * Set bit N of A.
+ */
+void
+mpi_set_bit( MPI a, unsigned n )
+{
+    unsigned limbno, bitno;
+
+    limbno = n / BITS_PER_MPI_LIMB;
+    bitno  = n % BITS_PER_MPI_LIMB;
+
+    if( limbno >= a->nlimbs ) { /* resize */
+	if( a->alloced >= limbno )
+	    mpi_resize(a, limbno+1 );
+	a->nlimbs = limbno+1;
+    }
+    a->d[limbno] |= (1<<bitno);
+}
+
+/****************
+ * Clear bit N of A.
+ */
+void
+mpi_clear_bit( MPI a, unsigned n )
+{
+    unsigned limbno, bitno;
+
+    limbno = n / BITS_PER_MPI_LIMB;
+    bitno  = n % BITS_PER_MPI_LIMB;
+
+    if( limbno >= a->nlimbs )
+	return; /* don't need to clear this bit, it's to far to left */
+    a->d[limbno] &= ~(1 << bitno);
+}
+
+
+void
+mpi_set_bytes( MPI a, unsigned nbits, byte (*fnc)(int), int opaque )
+{
+    byte *p;
+    unsigned nlimbs, nlimbs2, xbits, xbytes;
+    unsigned n;
+    int i;
+
+    nlimbs = nbits / BITS_PER_MPI_LIMB;
+    xbits = nbits % BITS_PER_MPI_LIMB;
+    nlimbs2 = xbits? (nlimbs+1):nlimbs;
+    xbytes = xbits / 8;
+    xbits = xbits % 8;
+    if( a->alloced < nlimbs2 )
+	mpi_resize(a, nlimbs2 );
+    a->nlimbs = nlimbs2;
+    for(n=0; n < nlimbs; n++ ) {
+	p = (byte*)(a->d+n);
+      #ifdef HAVE_LITTLE_ENDIAN
+	for(i=0; i < BYTES_PER_MPI_LIMB; i++ )
+	    p[i] = fnc(opaque);
+      #else
+	for(i=BYTES_PER_MPI_LIMB-1; i>=0; i-- )
+	    p[i] = fnc(opaque);
+      #endif
+    }
+    if( xbytes ) {
+	p = (byte*)(a->d+n);
+      #ifdef HAVE_LITTLE_ENDIAN
+	for(i=0; i < xbytes; i++ )
+	    p[i] = fnc(opaque);
+      #else
+	for(i=xbytes-1; i>=0; i-- )
+	    p[i] = fnc(opaque);
+      #endif
+    }
+    assert(!xbits);
+}
+
+