rdesktop/crypto/bn_shift.c

/* 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 "bn_lcl.h"

#if 0
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);
        }
#endif

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);
        }
1	/* crypto/bn/bn_shift.c */
2	/* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3	* All rights reserved.
4	*
5	* This package is an SSL implementation written
6	* by Eric Young (eay@cryptsoft.com).
7	* The implementation was written so as to conform with Netscapes SSL.
8	*
9	* This library is free for commercial and non-commercial use as long as
10	* the following conditions are aheared to. The following conditions
11	* apply to all code found in this distribution, be it the RC4, RSA,
12	* lhash, DES, etc., code; not just the SSL code. The SSL documentation
13	* included with this distribution is covered by the same copyright terms
14	* except that the holder is Tim Hudson (tjh@cryptsoft.com).
15	*
16	* Copyright remains Eric Young's, and as such any Copyright notices in
17	* the code are not to be removed.
18	* If this package is used in a product, Eric Young should be given attribution
19	* as the author of the parts of the library used.
20	* This can be in the form of a textual message at program startup or
21	* in documentation (online or textual) provided with the package.
22	*
23	* Redistribution and use in source and binary forms, with or without
24	* modification, are permitted provided that the following conditions
25	* are met:
26	* 1. Redistributions of source code must retain the copyright
27	* notice, this list of conditions and the following disclaimer.
28	* 2. Redistributions in binary form must reproduce the above copyright
29	* notice, this list of conditions and the following disclaimer in the
30	* documentation and/or other materials provided with the distribution.
31	* 3. All advertising materials mentioning features or use of this software
32	* must display the following acknowledgement:
33	* "This product includes cryptographic software written by
34	* Eric Young (eay@cryptsoft.com)"
35	* The word 'cryptographic' can be left out if the rouines from the library
36	* being used are not cryptographic related :-).
37	* 4. If you include any Windows specific code (or a derivative thereof) from
38	* the apps directory (application code) you must include an acknowledgement:
39	* "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
40	*
41	* THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
42	* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
43	* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
44	* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
45	* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
46	* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
47	* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
48	* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
49	* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
50	* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
51	* SUCH DAMAGE.
52	*
53	* The licence and distribution terms for any publically available version or
54	* derivative of this code cannot be changed. i.e. this code cannot simply be
55	* copied and put under another distribution licence
56	* [including the GNU Public Licence.]
57	*/
58
59	#include <stdio.h>
60	#include "bn_lcl.h"
61
62	#if 0
63	int BN_lshift1(BIGNUM r, BIGNUM a)
64	{
65	register BN_ULONG ap,rp,t,c;
66	int i;
67
68	if (r != a)
69	{
70	r->neg=a->neg;
71	if (bn_wexpand(r,a->top+1) == NULL) return(0);
72	r->top=a->top;
73	}
74	else
75	{
76	if (bn_wexpand(r,a->top+1) == NULL) return(0);
77	}
78	ap=a->d;
79	rp=r->d;
80	c=0;
81	for (i=0; i<a->top; i++)
82	{
83	t= *(ap++);
84	*(rp++)=((t<<1)\|c)&BN_MASK2;
85	c=(t & BN_TBIT)?1:0;
86	}
87	if (c)
88	{
89	*rp=1;
90	r->top++;
91	}
92	return(1);
93	}
94
95	int BN_rshift1(BIGNUM r, BIGNUM a)
96	{
97	BN_ULONG ap,rp,t,c;
98	int i;
99
100	if (BN_is_zero(a))
101	{
102	BN_zero(r);
103	return(1);
104	}
105	if (a != r)
106	{
107	if (bn_wexpand(r,a->top) == NULL) return(0);
108	r->top=a->top;
109	r->neg=a->neg;
110	}
111	ap=a->d;
112	rp=r->d;
113	c=0;
114	for (i=a->top-1; i>=0; i--)
115	{
116	t=ap[i];
117	rp[i]=((t>>1)&BN_MASK2)\|c;
118	c=(t&1)?BN_TBIT:0;
119	}
120	bn_fix_top(r);
121	return(1);
122	}
123	#endif
124
125	int BN_lshift(BIGNUM r, const BIGNUM a, int n)
126	{
127	int i,nw,lb,rb;
128	BN_ULONG t,f;
129	BN_ULONG l;
130
131	r->neg=a->neg;
132	if (bn_wexpand(r,a->top+(n/BN_BITS2)+1) == NULL) return(0);
133	nw=n/BN_BITS2;
134	lb=n%BN_BITS2;
135	rb=BN_BITS2-lb;
136	f=a->d;
137	t=r->d;
138	t[a->top+nw]=0;
139	if (lb == 0)
140	for (i=a->top-1; i>=0; i--)
141	t[nw+i]=f[i];
142	else
143	for (i=a->top-1; i>=0; i--)
144	{
145	l=f[i];
146	t[nw+i+1]\|=(l>>rb)&BN_MASK2;
147	t[nw+i]=(l<<lb)&BN_MASK2;
148	}
149	memset(t,0,nw*sizeof(t[0]));
150	/* for (i=0; i<nw; i++)
151	t[i]=0;*/
152	r->top=a->top+nw+1;
153	bn_fix_top(r);
154	return(1);
155	}
156
157	int BN_rshift(BIGNUM r, BIGNUM a, int n)
158	{
159	int i,j,nw,lb,rb;
160	BN_ULONG t,f;
161	BN_ULONG l,tmp;
162
163	nw=n/BN_BITS2;
164	rb=n%BN_BITS2;
165	lb=BN_BITS2-rb;
166	if (nw > a->top \|\| a->top == 0)
167	{
168	BN_zero(r);
169	return(1);
170	}
171	if (r != a)
172	{
173	r->neg=a->neg;
174	if (bn_wexpand(r,a->top-nw+1) == NULL) return(0);
175	}
176	else
177	{
178	if (n == 0)
179	return 1; /* or the copying loop will go berserk */
180	}
181
182	f= &(a->d[nw]);
183	t=r->d;
184	j=a->top-nw;
185	r->top=j;
186
187	if (rb == 0)
188	{
189	for (i=j+1; i > 0; i--)
190	(t++)= (f++);
191	}
192	else
193	{
194	l= *(f++);
195	for (i=1; i<j; i++)
196	{
197	tmp =(l>>rb)&BN_MASK2;
198	l= *(f++);
199	*(t++) =(tmp\|(l<<lb))&BN_MASK2;
200	}
201	*(t++) =(l>>rb)&BN_MASK2;
202	}
203	*t=0;
204	bn_fix_top(r);
205	return(1);
206	}