/* crypto/bn/bn_shift.c *//* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com) * All rights reserved. * * This package is an SSL implementation written * by Eric Young (eay@cryptsoft.com). * The implementation was written so as to conform with Netscapes SSL. *  * This library is free for commercial and non-commercial use as long as * the following conditions are aheared to.  The following conditions * apply to all code found in this distribution, be it the RC4, RSA, * lhash, DES, etc., code; not just the SSL code.  The SSL documentation * included with this distribution is covered by the same copyright terms * except that the holder is Tim Hudson (tjh@cryptsoft.com). *  * Copyright remains Eric Young's, and as such any Copyright notices in * the code are not to be removed. * If this package is used in a product, Eric Young should be given attribution * as the author of the parts of the library used. * This can be in the form of a textual message at program startup or * in documentation (online or textual) provided with the package. *  * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the copyright *    notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright *    notice, this list of conditions and the following disclaimer in the *    documentation and/or other materials provided with the distribution. * 3. All advertising materials mentioning features or use of this software *    must display the following acknowledgement: *    "This product includes cryptographic software written by *     Eric Young (eay@cryptsoft.com)" *    The word 'cryptographic' can be left out if the rouines from the library *    being used are not cryptographic related :-). * 4. If you include any Windows specific code (or a derivative thereof) from  *    the apps directory (application code) you must include an acknowledgement: *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)" *  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF * SUCH DAMAGE. *  * The licence and distribution terms for any publically available version or * derivative of this code cannot be changed.  i.e. this code cannot simply be * copied and put under another distribution licence * [including the GNU Public Licence.] */#include <stdio.h>#include "cryptlib.h"#include "bn_lcl.h"int BN_lshift1(BIGNUM * r, BIGNUM * a){    register BN_ULONG *ap, *rp, t, c;    int i;    if (r != a) {	r->neg = a->neg;	if (bn_wexpand(r, a->top + 1) == NULL)	    return (0);	r->top = a->top;    } else {	if (bn_wexpand(r, a->top + 1) == NULL)	    return (0);    }    ap = a->d;    rp = r->d;    c = 0;    for (i = 0; i < a->top; i++) {	t = *(ap++);	*(rp++) = ((t << 1) | c) & BN_MASK2;	c = (t & BN_TBIT) ? 1 : 0;    }    if (c) {	*rp = 1;	r->top++;    }    return (1);}int BN_rshift1(BIGNUM * r, BIGNUM * a){    BN_ULONG *ap, *rp, t, c;    int i;    if (BN_is_zero(a)) {	BN_zero(r);	return (1);    }    if (a != r) {	if (bn_wexpand(r, a->top) == NULL)	    return (0);	r->top = a->top;	r->neg = a->neg;    }    ap = a->d;    rp = r->d;    c = 0;    for (i = a->top - 1; i >= 0; i--) {	t = ap[i];	rp[i] = ((t >> 1) & BN_MASK2) | c;	c = (t & 1) ? BN_TBIT : 0;    }    bn_fix_top(r);    return (1);}int BN_lshift(BIGNUM * r, const BIGNUM * a, int n){    int i, nw, lb, rb;    BN_ULONG *t, *f;    BN_ULONG l;    r->neg = a->neg;    if (bn_wexpand(r, a->top + (n / BN_BITS2) + 1) == NULL)	return (0);    nw = n / BN_BITS2;    lb = n % BN_BITS2;    rb = BN_BITS2 - lb;    f = a->d;    t = r->d;    t[a->top + nw] = 0;    if (lb == 0)	for (i = a->top - 1; i >= 0; i--)	    t[nw + i] = f[i];    else	for (i = a->top - 1; i >= 0; i--) {	    l = f[i];	    t[nw + i + 1] |= (l >> rb) & BN_MASK2;	    t[nw + i] = (l << lb) & BN_MASK2;	}    memset(t, 0, nw * sizeof(t[0]));/*	for (i=0; i<nw; i++)		t[i]=0;*/    r->top = a->top + nw + 1;    bn_fix_top(r);    return (1);}int BN_rshift(BIGNUM * r, BIGNUM * a, int n){    int i, j, nw, lb, rb;    BN_ULONG *t, *f;    BN_ULONG l, tmp;    nw = n / BN_BITS2;    rb = n % BN_BITS2;    lb = BN_BITS2 - rb;    if (nw > a->top || a->top == 0) {	BN_zero(r);	return (1);    }    if (r != a) {	r->neg = a->neg;	if (bn_wexpand(r, a->top - nw + 1) == NULL)	    return (0);    } else {	if (n == 0)	    return 1;		/* or the copying loop will go berserk */    }    f = &(a->d[nw]);    t = r->d;    j = a->top - nw;    r->top = j;    if (rb == 0) {	for (i = j + 1; i > 0; i--)	    *(t++) = *(f++);    } else {	l = *(f++);	for (i = 1; i < j; i++) {	    tmp = (l >> rb) & BN_MASK2;	    l = *(f++);	    *(t++) = (tmp | (l << lb)) & BN_MASK2;	}	*(t++) = (l >> rb) & BN_MASK2;    }    *t = 0;    bn_fix_top(r);    return (1);}