Update head to match stable 1.0

mpi/mpi-bit.c

@@ -0,0 +1,262 @@
+/* mpi-bit.c  -  MPI bit level fucntions
+ * Copyright (C) 1998, 1999 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 <config.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include "mpi-internal.h"
+#include "longlong.h"
+
+
+#ifdef MPI_INTERNAL_NEED_CLZ_TAB
+#ifdef __STDC__
+const
+#endif
+unsigned char
+__clz_tab[] =
+{
+  0,1,2,2,3,3,3,3,4,4,4,4,4,4,4,4,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,5,
+  6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,6,
+  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+  7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,7,
+  8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+  8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+  8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+  8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,8,
+};
+#endif
+
+
+#define A_LIMB_1 ((mpi_limb_t)1)
+
+
+/****************
+ * Sometimes we have MSL (most significant limbs) which are 0;
+ * this is for some reasons not good, so this function removes them.
+ */
+void
+mpi_normalize( MPI a )
+{
+    if( mpi_is_protected(a) )
+	return;
+
+    for( ; a->nlimbs && !a->d[a->nlimbs-1]; a->nlimbs-- )
+	;
+}
+
+
+
+/****************
+ * Return the number of bits in A.
+ */
+unsigned
+mpi_get_nbits( MPI a )
+{
+    unsigned n;
+
+    if( mpi_is_protected(a) ) {
+	n = mpi_get_nbit_info(a);
+	if( !n )
+	    n = a->nlimbs * BITS_PER_MPI_LIMB;
+	return n;
+    }
+
+    mpi_normalize( a );
+    if( a->nlimbs ) {
+	mpi_limb_t alimb = a->d[a->nlimbs-1];
+	if( alimb )
+	    count_leading_zeros( n, alimb );
+	else
+	    n = BITS_PER_MPI_LIMB;
+	n = BITS_PER_MPI_LIMB - n + (a->nlimbs-1) * BITS_PER_MPI_LIMB;
+    }
+    else
+	n = 0;
+    return n;
+}
+
+
+/****************
+ * Test whether 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 & (A_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] |= (A_LIMB_1<<bitno);
+}
+
+/****************
+ * Set bit N of A. and clear all bits above
+ */
+void
+mpi_set_highbit( 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] |= (A_LIMB_1<<bitno);
+    for( bitno++; bitno < BITS_PER_MPI_LIMB; bitno++ )
+	a->d[limbno] &= ~(A_LIMB_1 << bitno);
+    a->nlimbs = limbno+1;
+}
+
+/****************
+ * clear bit N of A and all bits above
+ */
+void
+mpi_clear_highbit( MPI a, unsigned n )
+{
+    unsigned limbno, bitno;
+
+    limbno = n / BITS_PER_MPI_LIMB;
+    bitno  = n % BITS_PER_MPI_LIMB;
+
+    if( limbno >= a->nlimbs )
+	return; /* not allocated, so need to clear bits :-) */
+
+    for( ; bitno < BITS_PER_MPI_LIMB; bitno++ )
+	a->d[limbno] &= ~(A_LIMB_1 << bitno);
+    a->nlimbs = limbno+1;
+}
+
+/****************
+ * 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] &= ~(A_LIMB_1 << bitno);
+}
+
+
+/****************
+ * Shift A by N bits to the right
+ * FIXME: should use alloc_limb if X and A are same.
+ */
+void
+mpi_rshift( MPI x, MPI a, unsigned n )
+{
+    mpi_ptr_t xp;
+    mpi_size_t xsize;
+
+    xsize = a->nlimbs;
+    x->sign = a->sign;
+    RESIZE_IF_NEEDED(x, xsize);
+    xp = x->d;
+
+    if( xsize ) {
+	mpihelp_rshift( xp, a->d, xsize, n);
+	MPN_NORMALIZE( xp, xsize);
+    }
+    x->nlimbs = xsize;
+}
+
+
+/****************
+ * Shift A by COUNT limbs to the left
+ * This is used only within the MPI library
+ */
+void
+mpi_lshift_limbs( MPI a, unsigned int count )
+{
+    mpi_ptr_t ap = a->d;
+    int n = a->nlimbs;
+    int i;
+
+    if( !count || !n )
+	return;
+
+    RESIZE_IF_NEEDED( a, n+count );
+
+    for( i = n-1; i >= 0; i-- )
+	ap[i+count] = ap[i];
+    for(i=0; i < count; i++ )
+	ap[i] = 0;
+    a->nlimbs += count;
+}
+
+
+/****************
+ * Shift A by COUNT limbs to the right
+ * This is used only within the MPI library
+ */
+void
+mpi_rshift_limbs( MPI a, unsigned int count )
+{
+    mpi_ptr_t ap = a->d;
+    mpi_size_t n = a->nlimbs;
+    unsigned int i;
+
+    if( count >= n ) {
+	a->nlimbs = 0;
+	return;
+    }
+
+    for( i = 0; i < n - count; i++ )
+	ap[i] = ap[i+count];
+    ap[i] = 0;
+    a->nlimbs -= count;
+}
+
+