AppleCSP/open_ssl/bn/bn_shift.c

   1 /*
   2  * Copyright (c) 2000-2001 Apple Computer, Inc. All Rights Reserved.
   3  *
   4  * The contents of this file constitute Original Code as defined in and are
   5  * subject to the Apple Public Source License Version 1.2 (the 'License').
   6  * You may not use this file except in compliance with the License. Please obtain
   7  * a copy of the License at http://www.apple.com/publicsource and read it before
   8  * using this file.
   9  *
  10  * This Original Code and all software distributed under the License are
  11  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS
  12  * OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES, INCLUDING WITHOUT
  13  * LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR
  14  * PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. Please see the License for the
  15  * specific language governing rights and limitations under the License.
  16  */
  17
  18
  19 /* crypto/bn/bn_shift.c */
  20 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  21  * All rights reserved.
  22  *
  23  * This package is an SSL implementation written
  24  * by Eric Young (eay@cryptsoft.com).
  25  * The implementation was written so as to conform with Netscapes SSL.
  26  *
  27  * This library is free for commercial and non-commercial use as long as
  28  * the following conditions are aheared to.  The following conditions
  29  * apply to all code found in this distribution, be it the RC4, RSA,
  30  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  31  * included with this distribution is covered by the same copyright terms
  32  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  33  *
  34  * Copyright remains Eric Young's, and as such any Copyright notices in
  35  * the code are not to be removed.
  36  * If this package is used in a product, Eric Young should be given attribution
  37  * as the author of the parts of the library used.
  38  * This can be in the form of a textual message at program startup or
  39  * in documentation (online or textual) provided with the package.
  40  *
  41  * Redistribution and use in source and binary forms, with or without
  42  * modification, are permitted provided that the following conditions
  43  * are met:
  44  * 1. Redistributions of source code must retain the copyright
  45  *    notice, this list of conditions and the following disclaimer.
  46  * 2. Redistributions in binary form must reproduce the above copyright
  47  *    notice, this list of conditions and the following disclaimer in the
  48  *    documentation and/or other materials provided with the distribution.
  49  * 3. All advertising materials mentioning features or use of this software
  50  *    must display the following acknowledgement:
  51  *    "This product includes cryptographic software written by
  52  *     Eric Young (eay@cryptsoft.com)"
  53  *    The word 'cryptographic' can be left out if the rouines from the library
  54  *    being used are not cryptographic related :-).
  55  * 4. If you include any Windows specific code (or a derivative thereof) from
  56  *    the apps directory (application code) you must include an acknowledgement:
  57  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  58  *
  59  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  69  * SUCH DAMAGE.
  70  *
  71  * The licence and distribution terms for any publically available version or
  72  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  73  * copied and put under another distribution licence
  74  * [including the GNU Public Licence.]
  75  */
  76
  77 #include <stdio.h>
  78 #include "cryptlib.h"
  79 #include "bn_lcl.h"
  80
  81 int BN_lshift1(BIGNUM *r, BIGNUM *a)
  82         {
  83         register BN_ULONG *ap,*rp,t,c;
  84         int i;
  85
  86         if (r != a)
  87                 {
  88                 r->neg=a->neg;
  89                 if (bn_wexpand(r,a->top+1) == NULL) return(0);
  90                 r->top=a->top;
  91                 }
  92         else
  93                 {
  94                 if (bn_wexpand(r,a->top+1) == NULL) return(0);
  95                 }
  96         ap=a->d;
  97         rp=r->d;
  98         c=0;
  99         for (i=0; i<a->top; i++)
 100                 {
 101                 t= *(ap++);
 102                 *(rp++)=((t<<1)|c)&BN_MASK2;
 103                 c=(t & BN_TBIT)?1:0;
 104                 }
 105         if (c)
 106                 {
 107                 *rp=1;
 108                 r->top++;
 109                 }
 110         return(1);
 111         }
 112
 113 int BN_rshift1(BIGNUM *r, BIGNUM *a)
 114         {
 115         BN_ULONG *ap,*rp,t,c;
 116         int i;
 117
 118         if (BN_is_zero(a))
 119                 {
 120                 BN_zero(r);
 121                 return(1);
 122                 }
 123         if (a != r)
 124                 {
 125                 if (bn_wexpand(r,a->top) == NULL) return(0);
 126                 r->top=a->top;
 127                 r->neg=a->neg;
 128                 }
 129         ap=a->d;
 130         rp=r->d;
 131         c=0;
 132         for (i=a->top-1; i>=0; i--)
 133                 {
 134                 t=ap[i];
 135                 rp[i]=((t>>1)&BN_MASK2)|c;
 136                 c=(t&1)?BN_TBIT:0;
 137                 }
 138         bn_fix_top(r);
 139         return(1);
 140         }
 141
 142 int BN_lshift(BIGNUM *r, const BIGNUM *a, int n)
 143         {
 144         int i,nw,lb,rb;
 145         BN_ULONG *t,*f;
 146         BN_ULONG l;
 147
 148         r->neg=a->neg;
 149         if (bn_wexpand(r,a->top+(n/BN_BITS2)+1) == NULL) return(0);
 150         nw=n/BN_BITS2;
 151         lb=n%BN_BITS2;
 152         rb=BN_BITS2-lb;
 153         f=a->d;
 154         t=r->d;
 155         t[a->top+nw]=0;
 156         if (lb == 0)
 157                 for (i=a->top-1; i>=0; i--)
 158                         t[nw+i]=f[i];
 159         else
 160                 for (i=a->top-1; i>=0; i--)
 161                         {
 162                         l=f[i];
 163                         t[nw+i+1]|=(l>>rb)&BN_MASK2;
 164                         t[nw+i]=(l<<lb)&BN_MASK2;
 165                         }
 166         memset(t,0,nw*sizeof(t[0]));
 167 /*      for (i=0; i<nw; i++)
 168                 t[i]=0;*/
 169         r->top=a->top+nw+1;
 170         bn_fix_top(r);
 171         return(1);
 172         }
 173
 174 int BN_rshift(BIGNUM *r, BIGNUM *a, int n)
 175         {
 176         int i,j,nw,lb,rb;
 177         BN_ULONG *t,*f;
 178         BN_ULONG l,tmp;
 179
 180         nw=n/BN_BITS2;
 181         rb=n%BN_BITS2;
 182         lb=BN_BITS2-rb;
 183         if (nw > a->top)
 184                 {
 185                 BN_zero(r);
 186                 return(1);
 187                 }
 188         if (r != a)
 189                 {
 190                 r->neg=a->neg;
 191                 if (bn_wexpand(r,a->top-nw+1) == NULL) return(0);
 192                 }
 193
 194         f= &(a->d[nw]);
 195         t=r->d;
 196         j=a->top-nw;
 197         r->top=j;
 198
 199         if (rb == 0)
 200                 {
 201                 for (i=j+1; i > 0; i--)
 202                         *(t++)= *(f++);
 203                 }
 204         else
 205                 {
 206                 l= *(f++);
 207                 for (i=1; i<j; i++)
 208                         {
 209                         tmp =(l>>rb)&BN_MASK2;
 210                         l= *(f++);
 211                         *(t++) =(tmp|(l<<lb))&BN_MASK2;
 212                         }
 213                 *(t++) =(l>>rb)&BN_MASK2;
 214                 }
 215         *t=0;
 216         bn_fix_top(r);
 217         return(1);
 218         }