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1 /* LibTomMath, multiple-precision integer library -- Tom St Denis |
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2 * |
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3 * LibTomMath is a library that provides multiple-precision |
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4 * integer arithmetic as well as number theoretic functionality. |
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5 * |
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6 * The library was designed directly after the MPI library by |
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7 * Michael Fromberger but has been written from scratch with |
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8 * additional optimizations in place. |
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9 * |
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10 * The library is free for all purposes without any express |
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11 * guarantee it works. |
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12 * |
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13 * Tom St Denis, [email protected], http://math.libtomcrypt.org |
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14 */ |
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15 #include <tommath.h> |
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16 |
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17 /* determines if an integers is divisible by one |
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18 * of the first PRIME_SIZE primes or not |
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19 * |
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20 * sets result to 0 if not, 1 if yes |
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21 */ |
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22 int mp_prime_is_divisible (mp_int * a, int *result) |
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23 { |
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24 int err, ix; |
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25 mp_digit res; |
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26 |
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27 /* default to not */ |
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28 *result = MP_NO; |
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29 |
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30 for (ix = 0; ix < PRIME_SIZE; ix++) { |
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31 /* what is a mod __prime_tab[ix] */ |
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32 if ((err = mp_mod_d (a, __prime_tab[ix], &res)) != MP_OKAY) { |
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33 return err; |
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34 } |
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35 |
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36 /* is the residue zero? */ |
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37 if (res == 0) { |
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38 *result = MP_YES; |
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39 return MP_OKAY; |
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40 } |
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41 } |
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42 |
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43 return MP_OKAY; |
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44 } |
