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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 /* copy, b = a */ |
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18 int |
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19 mp_copy (mp_int * a, mp_int * b) |
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20 { |
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21 int res, n; |
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22 |
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23 /* if dst == src do nothing */ |
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24 if (a == b) { |
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25 return MP_OKAY; |
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26 } |
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27 |
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28 /* grow dest */ |
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29 if (b->alloc < a->used) { |
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30 if ((res = mp_grow (b, a->used)) != MP_OKAY) { |
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31 return res; |
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32 } |
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33 } |
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34 |
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35 /* zero b and copy the parameters over */ |
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36 { |
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37 register mp_digit *tmpa, *tmpb; |
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38 |
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39 /* pointer aliases */ |
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40 |
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41 /* source */ |
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42 tmpa = a->dp; |
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43 |
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44 /* destination */ |
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45 tmpb = b->dp; |
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46 |
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47 /* copy all the digits */ |
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48 for (n = 0; n < a->used; n++) { |
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49 *tmpb++ = *tmpa++; |
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50 } |
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51 |
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52 /* clear high digits */ |
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53 for (; n < b->used; n++) { |
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54 *tmpb++ = 0; |
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55 } |
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56 } |
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57 |
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58 /* copy used count and sign */ |
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59 b->used = a->used; |
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60 b->sign = a->sign; |
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61 return MP_OKAY; |
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62 } |
