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1 | /* -*-c-*- |
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2 | * |
3 | * Finding primitive elements |
4 | * |
5 | * (c) 1999 Straylight/Edgeware |
6 | */ |
7 | |
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8 | /*----- Licensing notice --------------------------------------------------* |
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9 | * |
10 | * This file is part of Catacomb. |
11 | * |
12 | * Catacomb is free software; you can redistribute it and/or modify |
13 | * it under the terms of the GNU Library General Public License as |
14 | * published by the Free Software Foundation; either version 2 of the |
15 | * License, or (at your option) any later version. |
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16 | * |
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17 | * Catacomb is distributed in the hope that it will be useful, |
18 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
19 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
20 | * GNU Library General Public License for more details. |
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21 | * |
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22 | * You should have received a copy of the GNU Library General Public |
23 | * License along with Catacomb; if not, write to the Free |
24 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
25 | * MA 02111-1307, USA. |
26 | */ |
27 | |
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28 | /*----- Header files ------------------------------------------------------*/ |
29 | |
30 | #include "mp.h" |
31 | #include "mpint.h" |
32 | #include "mpmont.h" |
33 | #include "mprand.h" |
34 | #include "pgen.h" |
35 | #include "prim.h" |
36 | |
37 | /*----- Main code ---------------------------------------------------------*/ |
38 | |
39 | /* --- @prim_test@ --- */ |
40 | |
41 | int prim_test(int rq, pgen_event *ev, void *p) |
42 | { |
43 | prim_ctx *c = p; |
44 | int rc = rq; |
45 | |
46 | switch (rq) { |
47 | case PGEN_BEGIN: |
48 | return (PGEN_TRY); |
49 | case PGEN_TRY: { |
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50 | mp *x; |
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51 | rc = PGEN_FAIL; |
52 | |
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53 | if (!c->exp) |
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54 | x = mp_copy(ev->m); |
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55 | else { |
56 | x = mpmont_exp(&c->mm, MP_NEW, ev->m, c->exp); |
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57 | if (MP_EQ(x, MP_ONE)) |
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58 | goto done; |
59 | } |
60 | if (c->n == 0) |
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61 | goto ok; |
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62 | else { |
63 | size_t n = c->n; |
64 | mp **f = c->f; |
65 | mp *y = MP_NEW; |
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66 | while (n) { |
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67 | y = mpmont_exp(&c->mm, y, x, *f); |
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68 | if (MP_EQ(y, MP_ONE)) { |
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69 | mp_drop(y); |
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70 | goto done; |
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71 | } |
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72 | n--; f++; |
73 | } |
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74 | mp_drop(y); |
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75 | } |
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76 | ok: |
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77 | rc = PGEN_DONE; |
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78 | mp_drop(ev->m); |
79 | ev->m = x; |
80 | break; |
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81 | done: |
82 | mp_drop(x); |
83 | } break; |
84 | } |
85 | |
86 | return (rc); |
87 | } |
88 | |
89 | /* --- Trivial stepping functions -----------------------------------------*/ |
90 | |
91 | /* --- @prim_step@ --- */ |
92 | |
93 | int prim_step(int rq, pgen_event *ev, void *p) |
94 | { |
95 | unsigned *i = p; |
96 | switch (rq) { |
97 | case PGEN_BEGIN: |
98 | case PGEN_TRY: |
99 | if (*i >= NPRIME) |
100 | return PGEN_FAIL; |
101 | ev->m = mp_fromint(ev->m, primetab[(*i)++]); |
102 | return (PGEN_TRY); |
103 | } |
104 | return (0); |
105 | } |
106 | |
107 | /*----- That's all, folks -------------------------------------------------*/ |