fcd15e0b |
1 | # -*-perl-*- |
2 | # |
3 | # $Id$ |
4 | # |
5 | # Binary polynomial arithmetic |
6 | # |
7 | # (c) 2004 Straylight/Edgeware |
8 | # |
9 | |
10 | #----- Licensing notice ----------------------------------------------------- |
11 | # |
12 | # This file is part of the Perl interface to Catacomb. |
13 | # |
14 | # Catacomb/Perl is free software; you can redistribute it and/or modify |
15 | # it under the terms of the GNU General Public License as published by |
16 | # the Free Software Foundation; either version 2 of the License, or |
17 | # (at your option) any later version. |
18 | # |
19 | # Catacomb/Perl 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 General Public License for more details. |
23 | # |
24 | # You should have received a copy of the GNU General Public License |
25 | # along with Catacomb/Perl; if not, write to the Free Software Foundation, |
26 | # Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. |
27 | |
28 | #----- Binary polynomials --------------------------------------------------- |
29 | |
30 | package Catacomb::GF; |
31 | use Catacomb::Base; |
32 | use Catacomb::MP; |
33 | use Carp; |
34 | |
35 | @ISA = qw(Catacomb::MP); |
36 | |
37 | sub gf { new(Catacomb::GF, $_[0]); } |
38 | sub gf_loadb { loadb(Catacomb::GF, $_[0]); } |
39 | sub gf_loadl { loadl(Catacomb::GF, $_[0]); } |
40 | sub gf_fromstring { fromstring(Catacomb::GF, $_[0]); } |
41 | |
42 | use overload |
43 | '+' => sub { _binop(\&add, @_); }, |
44 | '-' => sub { _binop(\&add, @_); }, |
45 | '*' => sub { _binop(\&mul, @_); }, |
46 | '/' => sub { _binop(\&div, @_); }, |
47 | '%' => sub { _binop(\&mod, @_); }, |
48 | '&' => sub { _binop(\&Catacomb::MP::and, @_); }, |
49 | '|' => sub { _binop(\&Catacomb::MP::or, @_); }, |
50 | '^' => sub { _binop(\&Catacomb::MP::xor, @_); }, |
51 | '**' => sub { _binop(\&pow, @_); }, |
52 | '>>' => sub { new(undef, &Catacomb::MP::lsr(@_[0, 1])); }, |
53 | '<<' => sub { new(undef, &Catacomb::MP::lsl(@_[0, 1])); }, |
54 | '~' => sub { new(undef, &Catacomb::MP::not($_[0])) }, |
55 | '==' => sub { _binop(\&Catacomb::MP::eq, @_); }, |
56 | '!=' => sub { !_binop(\&Catacomb::MP::eq, @_); }, |
57 | 'eq' => sub { _binop(\&Catacomb::MP::eq, @_); }, |
58 | 'ne' => sub { !_binop(\&Catacomb::MP::eq, @_); }, |
59 | '""' => sub { "0x" . &Catacomb::MP::tostring($_[0], 16); }, |
60 | 'neg' => sub { $_[0]; }, |
61 | '0+' => sub { &Catacomb::MP::toint($_[0]); }; |
62 | |
63 | sub binpolyfield { |
64 | croak("Usage: Catacomb::GF::binpolyfield(p)") unless @_ == 1; |
65 | return Catacomb::Field->binpoly($_[0]); |
66 | } |
67 | |
68 | sub binnormfield { |
69 | croak("Usage: Catacomb::GF::binnormfield(p, beta)") unless @_ == 2; |
70 | return Catacomb::Field->binnormfield($_[0], $_[1]); |
71 | } |
72 | |
73 | sub binpolygroup { |
74 | croak("Usage: Catacomb::GF::binpolygroup(p, g, q)") unless @_ == 3; |
75 | return Catacomb::Group->binary(@_); |
76 | } |
77 | |
78 | sub mod { (&div($_[0], $_[1]))[1]; } |
79 | |
80 | sub pow { |
81 | croak("Usage: Catacomb::GF::pow(a, b)") unless @_ == 2; |
82 | my ($a, $b) = @_; |
83 | my $r = Catacomb::GF->new(1); |
84 | while ($b) { |
85 | $r *= $a if $b & 1; |
86 | $a = sqr($a); |
87 | $b >>= 1; |
88 | } |
89 | return $r; |
90 | } |
91 | |
92 | sub _binop { |
93 | my ($func, $a, $b, $flag) = @_; |
94 | return new(undef, $flag ? &$func($b, $a) : &$func($a, $b)); |
95 | } |
96 | |
97 | sub modexp { |
98 | croak("Usage: Catacomb::GF::modexp(p, g, x)") unless @_ == 3; |
99 | my ($p, $g, $x) = @_; |
100 | my $r = Catacomb::GF::Reduce->new($p); |
101 | $g = $r->reduce($g); |
102 | return $r->exp($g, $x); |
103 | } |
104 | |
105 | sub modinv { |
106 | croak("Usage: Catacomb::GF::modinv(p, g)") unless @_ == 3; |
107 | my ($g, undef, $i) = gcd($_[0], $_[1]); |
108 | croak("Arguments aren't coprime in Catacomb::GF::modinv") unless $g == 1; |
109 | return $i; |
110 | } |
111 | |
112 | #----- That's all, folks ---------------------------------------------------- |