cscrypt/bn_word.c

   1 #include "bn.h"
   2
   3 #ifndef WITH_LIBCRYPTO
   4 //FIXME Not checked on threadsafety yet; after checking please remove this line
   5 /* crypto/bn/bn_word.c */
   6 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
   7  * All rights reserved.
   8  *
   9  * This package is an SSL implementation written
  10  * by Eric Young (eay@cryptsoft.com).
  11  * The implementation was written so as to conform with Netscapes SSL.
  12  *
  13  * This library is free for commercial and non-commercial use as long as
  14  * the following conditions are aheared to.  The following conditions
  15  * apply to all code found in this distribution, be it the RC4, RSA,
  16  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
  17  * included with this distribution is covered by the same copyright terms
  18  * except that the holder is Tim Hudson (tjh@cryptsoft.com).
  19  *
  20  * Copyright remains Eric Young's, and as such any Copyright notices in
  21  * the code are not to be removed.
  22  * If this package is used in a product, Eric Young should be given attribution
  23  * as the author of the parts of the library used.
  24  * This can be in the form of a textual message at program startup or
  25  * in documentation (online or textual) provided with the package.
  26  *
  27  * Redistribution and use in source and binary forms, with or without
  28  * modification, are permitted provided that the following conditions
  29  * are met:
  30  * 1. Redistributions of source code must retain the copyright
  31  *    notice, this list of conditions and the following disclaimer.
  32  * 2. Redistributions in binary form must reproduce the above copyright
  33  *    notice, this list of conditions and the following disclaimer in the
  34  *    documentation and/or other materials provided with the distribution.
  35  * 3. All advertising materials mentioning features or use of this software
  36  *    must display the following acknowledgement:
  37  *    "This product includes cryptographic software written by
  38  *     Eric Young (eay@cryptsoft.com)"
  39  *    The word 'cryptographic' can be left out if the rouines from the library
  40  *    being used are not cryptographic related :-).
  41  * 4. If you include any Windows specific code (or a derivative thereof) from
  42  *    the apps directory (application code) you must include an acknowledgement:
  43  *    "This product includes software written by Tim Hudson (tjh@cryptsoft.com)"
  44  *
  45  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
  46  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  47  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  48  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
  49  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  50  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
  51  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
  52  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
  53  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  54  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  55  * SUCH DAMAGE.
  56  *
  57  * The license and distribution terms for any publically available version or
  58  * derivative of this code cannot be changed.  i.e. this code cannot simply be
  59  * copied and put under another distribution license
  60  * [including the GNU Public License.]
  61  */
  62
  63 #include <stdio.h>
  64 #include "bn_lcl.h"
  65 #include "openssl_mods.h"
  66
  67 BN_ULONG BN_mod_word(const BIGNUM *a, BN_ULONG w)
  68 {
  69 #ifndef BN_LLONG
  70         BN_ULONG ret = 0;
  71 #else
  72         BN_ULLONG ret = 0;
  73 #endif
  74         int i;
  75
  76         w &= BN_MASK2;
  77         for(i = a->top - 1; i >= 0; i--)
  78         {
  79 #ifndef BN_LLONG
  80                 ret = ((ret << BN_BITS4) | ((a->d[i] >> BN_BITS4)&BN_MASK2l)) % w;
  81                 ret = ((ret << BN_BITS4) | (a->d[i] & BN_MASK2l)) % w;
  82 #else
  83                 ret = (BN_ULLONG)(((ret << (BN_ULLONG)BN_BITS2) | a->d[i]) %
  84                                                   (BN_ULLONG)w);
  85 #endif
  86         }
  87         return ((BN_ULONG)ret);
  88 }
  89
  90 BN_ULONG BN_div_word(BIGNUM *a, BN_ULONG w)
  91 {
  92         BN_ULONG ret;
  93         int i;
  94
  95         if(a->top == 0) { return (0); }
  96         ret = 0;
  97         w &= BN_MASK2;
  98         for(i = a->top - 1; i >= 0; i--)
  99         {
 100                 BN_ULONG l, d;
 101
 102                 l = a->d[i];
 103                 d = bn_div_words(ret, l, w);
 104                 ret = (l - ((d * w)&BN_MASK2))&BN_MASK2;
 105                 a->d[i] = d;
 106         }
 107         if((a->top > 0) && (a->d[a->top - 1] == 0))
 108                 { a->top--; }
 109         return (ret);
 110 }
 111
 112 int BN_add_word(BIGNUM *a, BN_ULONG w)
 113 {
 114         BN_ULONG l;
 115         int i;
 116
 117         if(a->neg)
 118         {
 119                 a->neg = 0;
 120                 i = BN_sub_word(a, w);
 121                 if(!BN_is_zero(a))
 122                         { a->neg = !(a->neg); }
 123                 return (i);
 124         }
 125         w &= BN_MASK2;
 126         if(bn_wexpand(a, a->top + 1) == NULL) { return (0); }
 127         i = 0;
 128         for(;;)
 129         {
 130                 l = (a->d[i] + (BN_ULONG)w)&BN_MASK2;
 131                 a->d[i] = l;
 132                 if(w > l)
 133                         { w = 1; }
 134                 else
 135                         { break; }
 136                 i++;
 137         }
 138         if(i >= a->top)
 139                 { a->top++; }
 140         return (1);
 141 }
 142
 143 int BN_sub_word(BIGNUM *a, BN_ULONG w)
 144 {
 145         int i;
 146
 147         if(BN_is_zero(a) || a->neg)
 148         {
 149                 a->neg = 0;
 150                 i = BN_add_word(a, w);
 151                 a->neg = 1;
 152                 return (i);
 153         }
 154
 155         w &= BN_MASK2;
 156         if((a->top == 1) && (a->d[0] < w))
 157         {
 158                 a->d[0] = w - a->d[0];
 159                 a->neg = 1;
 160                 return (1);
 161         }
 162         i = 0;
 163         for(;;)
 164         {
 165                 if(a->d[i] >= w)
 166                 {
 167                         a->d[i] -= w;
 168                         break;
 169                 }
 170                 else
 171                 {
 172                         a->d[i] = (a->d[i] - w)&BN_MASK2;
 173                         i++;
 174                         w = 1;
 175                 }
 176         }
 177         if((a->d[i] == 0) && (i == (a->top - 1)))
 178                 { a->top--; }
 179         return (1);
 180 }
 181
 182 int BN_mul_word(BIGNUM *a, BN_ULONG w)
 183 {
 184         BN_ULONG ll;
 185
 186         w &= BN_MASK2;
 187         if(a->top)
 188         {
 189                 if(w == 0)
 190                         { BN_zero(a); }
 191                 else
 192                 {
 193                         ll = bn_mul_words(a->d, a->d, a->top, w);
 194                         if(ll)
 195                         {
 196                                 if(bn_wexpand(a, a->top + 1) == NULL) { return (0); }
 197                                 a->d[a->top++] = ll;
 198                         }
 199                 }
 200         }
 201         return (1);
 202 }
 203
 204 #endif