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1 | /* -*-c-*- |
2 | * |
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3 | * $Id$ |
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4 | * |
5 | * Arithmetic on binary polynomials |
6 | * |
7 | * (c) 2004 Straylight/Edgeware |
8 | */ |
9 | |
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10 | /*----- Licensing notice --------------------------------------------------* |
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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. |
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18 | * |
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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. |
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23 | * |
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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 | |
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30 | #ifndef CATACOMB_GF_H |
31 | #define CATACOMB_GF_H |
32 | |
33 | #ifdef __cplusplus |
34 | extern "C" { |
35 | #endif |
36 | |
37 | /*----- Header files ------------------------------------------------------*/ |
38 | |
39 | #ifndef CATACOMB_MP_H |
40 | # include "mp.h" |
41 | #endif |
42 | |
43 | #ifndef CATACOMB_GFX_H |
44 | # include "gfx.h" |
45 | #endif |
46 | |
47 | /*----- Functions provided ------------------------------------------------*/ |
48 | |
49 | /* --- @gf_add@ --- * |
50 | * |
51 | * Arguments: @mp *d@ = destination |
52 | * @mp *a, *b@ = sources |
53 | * |
54 | * Returns: Result, @a@ added to @b@. |
55 | */ |
56 | |
57 | extern mp *gf_add(mp */*d*/, mp */*a*/, mp */*b*/); |
58 | #define gf_sub gf_add |
59 | |
60 | /* --- @gf_mul@ --- * |
61 | * |
62 | * Arguments: @mp *d@ = destination |
63 | * @mp *a, *b@ = sources |
64 | * |
65 | * Returns: Result, @a@ multiplied by @b@. |
66 | */ |
67 | |
68 | extern mp *gf_mul(mp */*d*/, mp */*a*/, mp */*b*/); |
69 | |
70 | /* --- @gf_sqr@ --- * |
71 | * |
72 | * Arguments: @mp *d@ = destination |
73 | * @mp *a@ = source |
74 | * |
75 | * Returns: Result, @a@ squared. |
76 | */ |
77 | |
78 | extern mp *gf_sqr(mp */*d*/, mp */*a*/); |
79 | |
80 | /* --- @gf_div@ --- * |
81 | * |
82 | * Arguments: @mp **qq, **rr@ = destination, quotient and remainder |
83 | * @mp *a, *b@ = sources |
84 | * |
85 | * Use: Calculates the quotient and remainder when @a@ is divided by |
86 | * @b@. The destinations @*qq@ and @*rr@ must be distinct. |
87 | * Either of @qq@ or @rr@ may be null to indicate that the |
88 | * result is irrelevant. (Discarding both results is silly.) |
89 | * There is a performance advantage if @a == *rr@. |
90 | */ |
91 | |
92 | extern void gf_div(mp **/*qq*/, mp **/*rr*/, mp */*a*/, mp */*b*/); |
93 | |
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94 | /* --- @gf_exp@ --- * |
95 | * |
96 | * Arguments: @mp *d@ = fake destination |
97 | * @mp *a@ = base |
98 | * @mp *e@ = exponent |
99 | * |
100 | * Returns: Result, %$a^e$%. |
101 | */ |
102 | |
103 | extern mp *gf_exp(mp */*d*/, mp */*a*/, mp */*e*/); |
104 | |
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105 | /* --- @gf_irreduciblep@ --- * |
106 | * |
107 | * Arguments: @mp *f@ = a polynomial |
108 | * |
109 | * Returns: Nonzero if the polynomial is irreducible; otherwise zero. |
110 | */ |
111 | |
112 | extern int gf_irreduciblep(mp */*f*/); |
113 | |
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114 | /* --- @gf_gcd@ --- * |
115 | * |
116 | * Arguments: @mp **gcd, **xx, **yy@ = where to write the results |
117 | * @mp *a, *b@ = sources (must be nonzero) |
118 | * |
119 | * |
120 | * Returns: --- |
121 | * |
122 | * Use: Calculates @gcd(a, b)@, and two numbers @x@ and @y@ such that |
123 | * @ax + by = gcd(a, b)@. This is useful for computing modular |
124 | * inverses. |
125 | */ |
126 | |
127 | extern void gf_gcd(mp **/*gcd*/, mp **/*xx*/, mp **/*yy*/, |
128 | mp */*a*/, mp */*b*/); |
129 | |
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130 | /* -- @gf_modinv@ --- * |
131 | * |
132 | * Arguments: @mp *d@ = destination |
133 | * @mp *x@ = argument |
134 | * @mp *p@ = modulus |
135 | * |
136 | * Returns: The inverse %$x^{-1} \bmod p$%. |
137 | * |
138 | * Use: Computes a modular inverse, the catch being that the |
139 | * arguments and results are binary polynomials. An assertion |
140 | * fails if %$p$% has no inverse. |
141 | */ |
142 | |
143 | extern mp *gf_modinv(mp */*d*/, mp */*x*/, mp */*p*/); |
144 | |
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145 | /*----- That's all, folks -------------------------------------------------*/ |
146 | |
147 | #ifdef __cplusplus |
148 | } |
149 | #endif |
150 | |
151 | #endif |