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      1 /* Copyright (C) 1995-1998 Eric Young (eay (at) cryptsoft.com)
      2  * All rights reserved.
      3  *
      4  * This package is an SSL implementation written
      5  * by Eric Young (eay (at) cryptsoft.com).
      6  * The implementation was written so as to conform with Netscapes SSL.
      7  *
      8  * This library is free for commercial and non-commercial use as long as
      9  * the following conditions are aheared to.  The following conditions
     10  * apply to all code found in this distribution, be it the RC4, RSA,
     11  * lhash, DES, etc., code; not just the SSL code.  The SSL documentation
     12  * included with this distribution is covered by the same copyright terms
     13  * except that the holder is Tim Hudson (tjh (at) cryptsoft.com).
     14  *
     15  * Copyright remains Eric Young's, and as such any Copyright notices in
     16  * the code are not to be removed.
     17  * If this package is used in a product, Eric Young should be given attribution
     18  * as the author of the parts of the library used.
     19  * This can be in the form of a textual message at program startup or
     20  * in documentation (online or textual) provided with the package.
     21  *
     22  * Redistribution and use in source and binary forms, with or without
     23  * modification, are permitted provided that the following conditions
     24  * are met:
     25  * 1. Redistributions of source code must retain the copyright
     26  *    notice, this list of conditions and the following disclaimer.
     27  * 2. Redistributions in binary form must reproduce the above copyright
     28  *    notice, this list of conditions and the following disclaimer in the
     29  *    documentation and/or other materials provided with the distribution.
     30  * 3. All advertising materials mentioning features or use of this software
     31  *    must display the following acknowledgement:
     32  *    "This product includes cryptographic software written by
     33  *     Eric Young (eay (at) cryptsoft.com)"
     34  *    The word 'cryptographic' can be left out if the rouines from the library
     35  *    being used are not cryptographic related :-).
     36  * 4. If you include any Windows specific code (or a derivative thereof) from
     37  *    the apps directory (application code) you must include an acknowledgement:
     38  *    "This product includes software written by Tim Hudson (tjh (at) cryptsoft.com)"
     39  *
     40  * THIS SOFTWARE IS PROVIDED BY ERIC YOUNG ``AS IS'' AND
     41  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     42  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
     43  * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
     44  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
     45  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
     46  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
     47  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
     48  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
     49  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
     50  * SUCH DAMAGE.
     51  *
     52  * The licence and distribution terms for any publically available version or
     53  * derivative of this code cannot be changed.  i.e. this code cannot simply be
     54  * copied and put under another distribution licence
     55  * [including the GNU Public Licence.] */
     56 
     57 #include <openssl/bn.h>
     58 
     59 #include "internal.h"
     60 
     61 
     62 int BN_ucmp(const BIGNUM *a, const BIGNUM *b) {
     63   int i;
     64   BN_ULONG t1, t2, *ap, *bp;
     65 
     66   i = a->top - b->top;
     67   if (i != 0) {
     68     return i;
     69   }
     70 
     71   ap = a->d;
     72   bp = b->d;
     73   for (i = a->top - 1; i >= 0; i--) {
     74     t1 = ap[i];
     75     t2 = bp[i];
     76     if (t1 != t2) {
     77       return (t1 > t2) ? 1 : -1;
     78     }
     79   }
     80 
     81   return 0;
     82 }
     83 
     84 int BN_cmp(const BIGNUM *a, const BIGNUM *b) {
     85   int i;
     86   int gt, lt;
     87   BN_ULONG t1, t2;
     88 
     89   if ((a == NULL) || (b == NULL)) {
     90     if (a != NULL) {
     91       return -1;
     92     } else if (b != NULL) {
     93       return 1;
     94     } else {
     95       return 0;
     96     }
     97   }
     98 
     99   if (a->neg != b->neg) {
    100     if (a->neg) {
    101       return -1;
    102     }
    103     return 1;
    104   }
    105   if (a->neg == 0) {
    106     gt = 1;
    107     lt = -1;
    108   } else {
    109     gt = -1;
    110     lt = 1;
    111   }
    112 
    113   if (a->top > b->top) {
    114     return gt;
    115   }
    116   if (a->top < b->top) {
    117     return lt;
    118   }
    119 
    120   for (i = a->top - 1; i >= 0; i--) {
    121     t1 = a->d[i];
    122     t2 = b->d[i];
    123     if (t1 > t2) {
    124       return gt;
    125     } if (t1 < t2) {
    126       return lt;
    127     }
    128   }
    129 
    130   return 0;
    131 }
    132 
    133 int bn_cmp_words(const BN_ULONG *a, const BN_ULONG *b, int n) {
    134   int i;
    135   BN_ULONG aa, bb;
    136 
    137   aa = a[n - 1];
    138   bb = b[n - 1];
    139   if (aa != bb) {
    140     return (aa > bb) ? 1 : -1;
    141   }
    142 
    143   for (i = n - 2; i >= 0; i--) {
    144     aa = a[i];
    145     bb = b[i];
    146     if (aa != bb) {
    147       return (aa > bb) ? 1 : -1;
    148     }
    149   }
    150   return 0;
    151 }
    152 
    153 int bn_cmp_part_words(const BN_ULONG *a, const BN_ULONG *b, int cl, int dl) {
    154   int n, i;
    155   n = cl - 1;
    156 
    157   if (dl < 0) {
    158     for (i = dl; i < 0; i++) {
    159       if (b[n - i] != 0) {
    160         return -1; /* a < b */
    161       }
    162     }
    163   }
    164   if (dl > 0) {
    165     for (i = dl; i > 0; i--) {
    166       if (a[n + i] != 0) {
    167         return 1; /* a > b */
    168       }
    169     }
    170   }
    171 
    172   return bn_cmp_words(a, b, cl);
    173 }
    174 
    175 int BN_abs_is_word(const BIGNUM *bn, BN_ULONG w) {
    176   switch (bn->top) {
    177     case 1:
    178       return bn->d[0] == w;
    179     case 0:
    180       return w == 0;
    181     default:
    182       return 0;
    183   }
    184 }
    185 
    186 int BN_is_zero(const BIGNUM *bn) {
    187   return bn->top == 0;
    188 }
    189 
    190 int BN_is_one(const BIGNUM *bn) {
    191   return bn->neg == 0 && BN_abs_is_word(bn, 1);
    192 }
    193 
    194 int BN_is_word(const BIGNUM *bn, BN_ULONG w) {
    195   return BN_abs_is_word(bn, w) && (w == 0 || bn->neg == 0);
    196 }
    197 
    198 int BN_is_odd(const BIGNUM *bn) {
    199   return bn->top > 0 && (bn->d[0] & 1) == 1;
    200 }
    201