Import OpenSSL-0.9.8i.
[dragonfly.git] / crypto / openssl-0.9.7d / crypto / bn / bn_shift.c
blob70f785ea185b8841e415d33b385bf96de95535be
1 /* crypto/bn/bn_shift.c */
2 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
3 * All rights reserved.
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).
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.
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)"
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.
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.]
59 #include <stdio.h>
60 #include "cryptlib.h"
61 #include "bn_lcl.h"
63 int BN_lshift1(BIGNUM *r, const BIGNUM *a)
65 register BN_ULONG *ap,*rp,t,c;
66 int i;
68 if (r != a)
70 r->neg=a->neg;
71 if (bn_wexpand(r,a->top+1) == NULL) return(0);
72 r->top=a->top;
74 else
76 if (bn_wexpand(r,a->top+1) == NULL) return(0);
78 ap=a->d;
79 rp=r->d;
80 c=0;
81 for (i=0; i<a->top; i++)
83 t= *(ap++);
84 *(rp++)=((t<<1)|c)&BN_MASK2;
85 c=(t & BN_TBIT)?1:0;
87 if (c)
89 *rp=1;
90 r->top++;
92 return(1);
95 int BN_rshift1(BIGNUM *r, const BIGNUM *a)
97 BN_ULONG *ap,*rp,t,c;
98 int i;
100 if (BN_is_zero(a))
102 BN_zero(r);
103 return(1);
105 if (a != r)
107 if (bn_wexpand(r,a->top) == NULL) return(0);
108 r->top=a->top;
109 r->neg=a->neg;
111 ap=a->d;
112 rp=r->d;
113 c=0;
114 for (i=a->top-1; i>=0; i--)
116 t=ap[i];
117 rp[i]=((t>>1)&BN_MASK2)|c;
118 c=(t&1)?BN_TBIT:0;
120 bn_fix_top(r);
121 return(1);
124 int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
126 int i,nw,lb,rb;
127 BN_ULONG *t,*f;
128 BN_ULONG l;
130 r->neg=a->neg;
131 nw=n/BN_BITS2;
132 if (bn_wexpand(r,a->top+nw+1) == NULL) return(0);
133 lb=n%BN_BITS2;
134 rb=BN_BITS2-lb;
135 f=a->d;
136 t=r->d;
137 t[a->top+nw]=0;
138 if (lb == 0)
139 for (i=a->top-1; i>=0; i--)
140 t[nw+i]=f[i];
141 else
142 for (i=a->top-1; i>=0; i--)
144 l=f[i];
145 t[nw+i+1]|=(l>>rb)&BN_MASK2;
146 t[nw+i]=(l<<lb)&BN_MASK2;
148 memset(t,0,nw*sizeof(t[0]));
149 /* for (i=0; i<nw; i++)
150 t[i]=0;*/
151 r->top=a->top+nw+1;
152 bn_fix_top(r);
153 return(1);
156 int BN_rshift(BIGNUM *r, const BIGNUM *a, int n)
158 int i,j,nw,lb,rb;
159 BN_ULONG *t,*f;
160 BN_ULONG l,tmp;
162 nw=n/BN_BITS2;
163 rb=n%BN_BITS2;
164 lb=BN_BITS2-rb;
165 if (nw > a->top || a->top == 0)
167 BN_zero(r);
168 return(1);
170 if (r != a)
172 r->neg=a->neg;
173 if (bn_wexpand(r,a->top-nw+1) == NULL) return(0);
175 else
177 if (n == 0)
178 return 1; /* or the copying loop will go berserk */
181 f= &(a->d[nw]);
182 t=r->d;
183 j=a->top-nw;
184 r->top=j;
186 if (rb == 0)
188 for (i=j+1; i > 0; i--)
189 *(t++)= *(f++);
191 else
193 l= *(f++);
194 for (i=1; i<j; i++)
196 tmp =(l>>rb)&BN_MASK2;
197 l= *(f++);
198 *(t++) =(tmp|(l<<lb))&BN_MASK2;
200 *(t++) =(l>>rb)&BN_MASK2;
202 *t=0;
203 bn_fix_top(r);
204 return(1);