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f46efa79 | 1 | /* -*-c-*- |
f46efa79 | 2 | * |
3 | * Efficient reduction modulo nice primes | |
4 | * | |
5 | * (c) 2004 Straylight/Edgeware | |
6 | */ | |
7 | ||
45c0fd36 | 8 | /*----- Licensing notice --------------------------------------------------* |
f46efa79 | 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. | |
45c0fd36 | 16 | * |
f46efa79 | 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. | |
45c0fd36 | 21 | * |
f46efa79 | 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 | ||
f46efa79 | 28 | #ifndef CATACOMB_MPREDUCE_H |
29 | #define CATACOMB_MPREDUCE_H | |
30 | ||
31 | #ifdef __cplusplus | |
32 | extern "C" { | |
33 | #endif | |
34 | ||
35 | /*----- Header files ------------------------------------------------------*/ | |
36 | ||
3e248c3b MW |
37 | #include <stdio.h> |
38 | ||
39 | #ifndef CATACOMB_MP_H | |
40 | # include "mp.h" | |
41 | #endif | |
42 | ||
f46efa79 | 43 | /*----- Data structures ---------------------------------------------------*/ |
44 | ||
45 | typedef struct mpreduce_instr { | |
46 | unsigned op; /* Instruction opcode */ | |
47 | size_t argx, argy; /* Immediate arguments */ | |
48 | } mpreduce_instr; | |
49 | ||
50 | enum { | |
51 | MPRI_ADD, /* Add @p@ offset by @x@ words */ | |
52 | MPRI_ADDLSL, /* Add @p << y@ offset by @x@ */ | |
53 | MPRI_SUB, /* Sub @p@ offset by @x@ words */ | |
54 | MPRI_SUBLSL, /* Sub @p << y@ offset by @x@ */ | |
55 | MPRI_MAX | |
56 | }; | |
57 | ||
58 | typedef struct mpreduce { | |
59 | size_t lim; /* Word containing top bit */ | |
60 | unsigned s; /* Shift for top word */ | |
61 | mp *p; /* Copy of the modulus */ | |
62 | size_t in; /* Number of instruction words */ | |
63 | mpreduce_instr *iv; /* Vector of instructions */ | |
64 | } mpreduce; | |
65 | ||
66 | /*----- Functions provided ------------------------------------------------*/ | |
67 | ||
68 | /* --- @mpreduce_create@ --- * | |
69 | * | |
70 | * Arguments: @gfreduce *r@ = structure to fill in | |
71 | * @mp *x@ = an integer | |
72 | * | |
30d09778 MW |
73 | * Returns: Zero if successful; nonzero on failure. The current |
74 | * algorithm always succeeds when given positive @x@. Earlier | |
75 | * versions used to fail on particular kinds of integers, but | |
76 | * this is guaranteed not to happen any more. | |
f46efa79 | 77 | * |
78 | * Use: Initializes a context structure for reduction. | |
79 | */ | |
80 | ||
f4535c64 | 81 | extern int mpreduce_create(mpreduce */*r*/, mp */*p*/); |
f46efa79 | 82 | |
83 | /* --- @mpreduce_destroy@ --- * | |
84 | * | |
85 | * Arguments: @mpreduce *r@ = structure to free | |
86 | * | |
87 | * Returns: --- | |
88 | * | |
89 | * Use: Reclaims the resources from a reduction context. | |
90 | */ | |
91 | ||
92 | extern void mpreduce_destroy(mpreduce */*r*/); | |
93 | ||
94 | /* --- @mpreduce_dump@ --- * | |
95 | * | |
96 | * Arguments: @mpreduce *r@ = structure to dump | |
97 | * @FILE *fp@ = file to dump on | |
98 | * | |
99 | * Returns: --- | |
100 | * | |
101 | * Use: Dumps a reduction context. | |
102 | */ | |
103 | ||
104 | extern void mpreduce_dump(mpreduce */*r*/, FILE */*fp*/); | |
105 | ||
106 | /* --- @mpreduce_do@ --- * | |
107 | * | |
108 | * Arguments: @mpreduce *r@ = reduction context | |
109 | * @mp *d@ = destination | |
110 | * @mp *x@ = source | |
111 | * | |
112 | * Returns: Destination, @x@ reduced modulo the reduction poly. | |
113 | */ | |
114 | ||
115 | extern mp *mpreduce_do(mpreduce */*r*/, mp */*d*/, mp */*x*/); | |
116 | ||
117 | /* --- @mpreduce_exp@ --- * | |
118 | * | |
119 | * Arguments: @mpreduce *mr@ = pointer to reduction context | |
45c0fd36 MW |
120 | * @mp *d@ = fake destination |
121 | * @mp *a@ = base | |
122 | * @mp *e@ = exponent | |
f46efa79 | 123 | * |
45c0fd36 | 124 | * Returns: Result, %$a^e \bmod m$%. |
f46efa79 | 125 | */ |
126 | ||
127 | extern mp *mpreduce_exp(mpreduce */*mr*/, mp */*d*/, mp */*a*/, mp */*e*/); | |
128 | ||
129 | /*----- That's all, folks -------------------------------------------------*/ | |
130 | ||
131 | #ifdef __cplusplus | |
132 | } | |
133 | #endif | |
134 | ||
135 | #endif |