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1 | /* -*-c-*- |
2 | * |
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3 | * $Id: field.c,v 1.3 2004/04/01 12:50:09 mdw Exp $ |
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4 | * |
5 | * Abstract field operations |
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6 | * |
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7 | * (c) 2001 Straylight/Edgeware |
8 | */ |
9 | |
10 | /*----- Licensing notice --------------------------------------------------* |
11 | * |
12 | * This file is part of Catacomb. |
13 | * |
14 | * Catacomb is free software; you can redistribute it and/or modify |
15 | * it under the terms of the GNU Library General Public License as |
16 | * published by the Free Software Foundation; either version 2 of the |
17 | * License, or (at your option) any later version. |
18 | * |
19 | * Catacomb is distributed in the hope that it will be useful, |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
22 | * GNU Library General Public License for more details. |
23 | * |
24 | * You should have received a copy of the GNU Library General Public |
25 | * License along with Catacomb; if not, write to the Free |
26 | * Software Foundation, Inc., 59 Temple Place - Suite 330, Boston, |
27 | * MA 02111-1307, USA. |
28 | */ |
29 | |
30 | /*----- Revision history --------------------------------------------------* |
31 | * |
32 | * $Log: field.c,v $ |
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33 | * Revision 1.3 2004/04/01 12:50:09 mdw |
34 | * Add cyclic group abstraction, with test code. Separate off exponentation |
35 | * functions for better static linking. Fix a buttload of bugs on the way. |
36 | * Generally ensure that negative exponents do inversion correctly. Add |
37 | * table of standard prime-field subgroups. (Binary field subgroups are |
38 | * currently unimplemented but easy to add if anyone ever finds a good one.) |
39 | * |
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40 | * Revision 1.2 2004/03/21 22:52:06 mdw |
41 | * Merge and close elliptic curve branch. |
42 | * |
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43 | * Revision 1.1.4.1 2003/06/10 13:43:53 mdw |
44 | * Simple (non-projective) curves over prime fields now seem to work. |
45 | * |
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46 | * Revision 1.1 2001/05/07 17:30:13 mdw |
47 | * Add an internal-representation no-op function. |
48 | * |
49 | */ |
50 | |
51 | /*----- Header files ------------------------------------------------------*/ |
52 | |
53 | #include "field.h" |
54 | #include "mp.h" |
55 | |
56 | /*----- Main code ---------------------------------------------------------*/ |
57 | |
58 | /* --- @field_id@ --- * |
59 | * |
60 | * Arguments: @field *f@ = pointer to a field |
61 | * @mp *d@ = a destination element |
62 | * @mp *x@ = a source element |
63 | * |
64 | * Returns: The result element. |
65 | * |
66 | * Use: An identity operation which can be used if your field has no |
67 | * internal representation. |
68 | */ |
69 | |
70 | mp *field_id(field *f, mp *d, mp *x) |
71 | { |
72 | x = MP_COPY(x); |
73 | if (d) MP_DROP(d); |
74 | return (x); |
75 | } |
76 | |
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77 | /* --- @field_samep@ --- * |
78 | * |
79 | * Arguments: @field *f, *g@ = two fields |
80 | * |
81 | * Returns: Nonzero if the fields are identical (not just isomorphic). |
82 | * |
83 | * Use: Checks for sameness of fields. This function does the full |
84 | * check, not just the field-type-specific check done by the |
85 | * @sampep@ field operation. |
86 | */ |
87 | |
88 | int field_samep(field *f, field *g) |
89 | { |
90 | return (f->ops == g->ops && F_SAMEP(f, g)); |
91 | } |
92 | |
93 | /* --- @field_stdsamep@ --- * |
94 | * |
95 | * Arguments: @field *f, *g@ = two fields |
96 | * |
97 | * Returns: Nonzero if the fields are identical (not just isomorphic). |
98 | * |
99 | * Use: Standard sameness check, based on equality of the @m@ |
100 | * member. |
101 | */ |
102 | |
103 | int field_stdsamep(field *f, field *g) |
104 | { |
105 | return (MP_EQ(f->m, g->m)); |
106 | } |
107 | |
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108 | /*----- That's all, folks -------------------------------------------------*/ |