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1 | package bigint; |
2 | require 5.005; |
3 | |
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4 | $VERSION = '0.03'; |
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5 | use Exporter; |
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6 | @ISA = qw( Exporter ); |
7 | @EXPORT_OK = qw( ); |
8 | @EXPORT = qw( inf NaN ); |
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9 | |
10 | use strict; |
11 | use overload; |
12 | |
13 | ############################################################################## |
14 | |
15 | # These are all alike, and thus faked by AUTOLOAD |
16 | |
17 | my @faked = qw/round_mode accuracy precision div_scale/; |
18 | use vars qw/$VERSION $AUTOLOAD $_lite/; # _lite for testsuite |
19 | |
20 | sub AUTOLOAD |
21 | { |
22 | my $name = $AUTOLOAD; |
23 | |
24 | $name =~ s/.*:://; # split package |
25 | no strict 'refs'; |
26 | foreach my $n (@faked) |
27 | { |
28 | if ($n eq $name) |
29 | { |
30 | *{"bigint::$name"} = sub |
31 | { |
32 | my $self = shift; |
33 | no strict 'refs'; |
34 | if (defined $_[0]) |
35 | { |
36 | Math::BigInt->$name($_[0]); |
37 | } |
38 | return Math::BigInt->$name(); |
39 | }; |
40 | return &$name; |
41 | } |
42 | } |
43 | |
44 | # delayed load of Carp and avoid recursion |
45 | require Carp; |
46 | Carp::croak ("Can't call bigint\-\>$name, not a valid method"); |
47 | } |
48 | |
49 | sub upgrade |
50 | { |
51 | my $self = shift; |
52 | no strict 'refs'; |
53 | # if (defined $_[0]) |
54 | # { |
55 | # $Math::BigInt::upgrade = $_[0]; |
56 | # } |
57 | return $Math::BigInt::upgrade; |
58 | } |
59 | |
60 | sub _constant |
61 | { |
62 | # this takes a floating point constant string and returns it truncated to |
63 | # integer. For instance, '4.5' => '4', '1.234e2' => '123' etc |
64 | my $float = shift; |
65 | |
66 | # some simple cases first |
67 | return $float if ($float =~ /^[+-]?[0-9]+$/); # '+123','-1','0' etc |
68 | return $float |
69 | if ($float =~ /^[+-]?[0-9]+\.?[eE]\+?[0-9]+$/); # 123e2, 123.e+2 |
70 | return '0' if ($float =~ /^[+-]?[0]*\.[0-9]+$/); # .2, 0.2, -.1 |
71 | if ($float =~ /^[+-]?[0-9]+\.[0-9]*$/) # 1., 1.23, -1.2 etc |
72 | { |
73 | $float =~ s/\..*//; |
74 | return $float; |
75 | } |
76 | my ($mis,$miv,$mfv,$es,$ev) = Math::BigInt::_split(\$float); |
77 | return $float if !defined $mis; # doesn't look like a number to me |
78 | my $ec = int($$ev); |
79 | my $sign = $$mis; $sign = '' if $sign eq '+'; |
80 | if ($$es eq '-') |
81 | { |
82 | # ignore fraction part entirely |
83 | if ($ec >= length($$miv)) # 123.23E-4 |
84 | { |
85 | return '0'; |
86 | } |
87 | return $sign . substr ($$miv,0,length($$miv)-$ec); # 1234.45E-2 = 12 |
88 | } |
89 | # xE+y |
90 | if ($ec >= length($$mfv)) |
91 | { |
92 | $ec -= length($$mfv); |
93 | return $sign.$$miv.$$mfv if $ec == 0; # 123.45E+2 => 12345 |
94 | return $sign.$$miv.$$mfv.'E'.$ec; # 123.45e+3 => 12345e1 |
95 | } |
96 | $mfv = substr($$mfv,0,$ec); |
97 | return $sign.$$miv.$mfv; # 123.45e+1 => 1234 |
98 | } |
99 | |
100 | sub import |
101 | { |
102 | my $self = shift; |
103 | |
104 | # some defaults |
105 | my $lib = 'Calc'; |
106 | |
107 | my @import = ( ':constant' ); # drive it w/ constant |
108 | my @a = @_; my $l = scalar @_; my $j = 0; |
109 | my ($ver,$trace); # version? trace? |
110 | my ($a,$p); # accuracy, precision |
111 | for ( my $i = 0; $i < $l ; $i++,$j++ ) |
112 | { |
113 | if ($_[$i] =~ /^(l|lib)$/) |
114 | { |
115 | # this causes a different low lib to take care... |
116 | $lib = $_[$i+1] || ''; |
117 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." |
118 | splice @a, $j, $s; $j -= $s; $i++; |
119 | } |
120 | elsif ($_[$i] =~ /^(a|accuracy)$/) |
121 | { |
122 | $a = $_[$i+1]; |
123 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." |
124 | splice @a, $j, $s; $j -= $s; $i++; |
125 | } |
126 | elsif ($_[$i] =~ /^(p|precision)$/) |
127 | { |
128 | $p = $_[$i+1]; |
129 | my $s = 2; $s = 1 if @a-$j < 2; # avoid "can not modify non-existant..." |
130 | splice @a, $j, $s; $j -= $s; $i++; |
131 | } |
132 | elsif ($_[$i] =~ /^(v|version)$/) |
133 | { |
134 | $ver = 1; |
135 | splice @a, $j, 1; $j --; |
136 | } |
137 | elsif ($_[$i] =~ /^(t|trace)$/) |
138 | { |
139 | $trace = 1; |
140 | splice @a, $j, 1; $j --; |
141 | } |
142 | else { die "unknown option $_[$i]"; } |
143 | } |
144 | my $class; |
145 | $_lite = 0; # using M::BI::L ? |
146 | if ($trace) |
147 | { |
148 | require Math::BigInt::Trace; $class = 'Math::BigInt::Trace'; |
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149 | } |
150 | else |
151 | { |
152 | # see if we can find Math::BigInt::Lite |
153 | if (!defined $a && !defined $p) # rounding won't work to well |
154 | { |
155 | eval 'require Math::BigInt::Lite;'; |
156 | if ($@ eq '') |
157 | { |
158 | @import = ( ); # :constant in Lite, not MBI |
159 | Math::BigInt::Lite->import( ':constant' ); |
160 | $_lite= 1; # signal okay |
161 | } |
162 | } |
163 | require Math::BigInt if $_lite == 0; # not already loaded? |
164 | $class = 'Math::BigInt'; # regardless of MBIL or not |
165 | } |
166 | # Math::BigInt::Trace or plain Math::BigInt |
167 | $class->import(@import, lib => $lib); |
168 | |
169 | bigint->accuracy($a) if defined $a; |
170 | bigint->precision($p) if defined $p; |
171 | if ($ver) |
172 | { |
173 | print "bigint\t\t\t v$VERSION\n"; |
174 | print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite; |
175 | print "Math::BigInt\t\t v$Math::BigInt::VERSION"; |
176 | my $config = Math::BigInt->config(); |
177 | print " lib => $config->{lib} v$config->{lib_version}\n"; |
178 | exit; |
179 | } |
180 | # we take care of floating point constants, since BigFloat isn't available |
181 | # and BigInt doesn't like them: |
182 | overload::constant float => sub { Math::BigInt->new( _constant(shift) ); }; |
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183 | |
184 | $self->export_to_level(1,$self,@a); # export inf and NaN |
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185 | } |
186 | |
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187 | sub inf () { Math::BigInt->binf(); } |
188 | sub NaN () { Math::BigInt->bnan(); } |
189 | |
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190 | 1; |
191 | |
192 | __END__ |
193 | |
194 | =head1 NAME |
195 | |
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196 | bigint - Transparent BigInteger support for Perl |
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197 | |
198 | =head1 SYNOPSIS |
199 | |
200 | use bignt; |
201 | |
202 | $x = 2 + 4.5,"\n"; # BigInt 6 |
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203 | print 2 ** 512,"\n"; # really is what you think it is |
204 | print inf + 42,"\n"; # inf |
205 | print NaN * 7,"\n"; # NaN |
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206 | |
207 | =head1 DESCRIPTION |
208 | |
209 | All operators (including basic math operations) are overloaded. Integer |
210 | constants are created as proper BigInts. |
211 | |
212 | Floating point constants are truncated to integer. All results are also |
213 | trunctaed. |
214 | |
215 | =head2 OPTIONS |
216 | |
217 | bigint recognizes some options that can be passed while loading it via use. |
218 | The options can (currently) be either a single letter form, or the long form. |
219 | The following options exist: |
220 | |
221 | =over 2 |
222 | |
223 | =item a or accuracy |
224 | |
225 | This sets the accuracy for all math operations. The argument must be greater |
226 | than or equal to zero. See Math::BigInt's bround() function for details. |
227 | |
228 | perl -Mbigint=a,2 -le 'print 12345+1' |
229 | |
230 | =item p or precision |
231 | |
232 | This sets the precision for all math operations. The argument can be any |
233 | integer. Negative values mean a fixed number of digits after the dot, and |
234 | are <B>ignored</B> since all operations happen in integer space. |
235 | A positive value rounds to this digit left from the dot. 0 or 1 mean round to |
236 | integer and are ignore like negative values. |
237 | |
238 | See Math::BigInt's bfround() function for details. |
239 | |
240 | perl -Mbignum=p,5 -le 'print 123456789+123' |
241 | |
242 | =item t or trace |
243 | |
244 | This enables a trace mode and is primarily for debugging bigint or |
245 | Math::BigInt. |
246 | |
247 | =item l or lib |
248 | |
249 | Load a different math lib, see L<MATH LIBRARY>. |
250 | |
251 | perl -Mbigint=l,GMP -e 'print 2 ** 512' |
252 | |
253 | Currently there is no way to specify more than one library on the command |
254 | line. This will be hopefully fixed soon ;) |
255 | |
256 | =item v or version |
257 | |
258 | This prints out the name and version of all modules used and then exits. |
259 | |
260 | perl -Mbigint=v -e '' |
261 | |
262 | =head2 MATH LIBRARY |
263 | |
264 | Math with the numbers is done (by default) by a module called |
265 | Math::BigInt::Calc. This is equivalent to saying: |
266 | |
267 | use bigint lib => 'Calc'; |
268 | |
269 | You can change this by using: |
270 | |
271 | use bigint lib => 'BitVect'; |
272 | |
273 | The following would first try to find Math::BigInt::Foo, then |
274 | Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc: |
275 | |
276 | use bigint lib => 'Foo,Math::BigInt::Bar'; |
277 | |
278 | Please see respective module documentation for further details. |
279 | |
280 | =head2 INTERNAL FORMAT |
281 | |
282 | The numbers are stored as objects, and their internals might change at anytime, |
283 | especially between math operations. The objects also might belong to different |
284 | classes, like Math::BigInt, or Math::BigInt::Lite. Mixing them together, even |
285 | with normal scalars is not extraordinary, but normal and expected. |
286 | |
287 | You should not depend on the internal format, all accesses must go through |
288 | accessor methods. E.g. looking at $x->{sign} is not a bright idea since there |
289 | is no guaranty that the object in question has such a hash key, nor is a hash |
290 | underneath at all. |
291 | |
292 | =head2 SIGN |
293 | |
294 | The sign is either '+', '-', 'NaN', '+inf' or '-inf' and stored seperately. |
295 | You can access it with the sign() method. |
296 | |
297 | A sign of 'NaN' is used to represent the result when input arguments are not |
298 | numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively |
299 | minus infinity. You will get '+inf' when dividing a positive number by 0, and |
300 | '-inf' when dividing any negative number by 0. |
301 | |
302 | =head2 METHODS |
303 | |
304 | Since all numbers are now objects, you can use all functions that are part of |
305 | the BigInt API. You can only use the bxxx() notation, and not the fxxx() |
306 | notation, though. |
307 | |
308 | =head1 MODULES USED |
309 | |
310 | C<bigint> is just a thin wrapper around various modules of the Math::BigInt |
311 | family. Think of it as the head of the family, who runs the shop, and orders |
312 | the others to do the work. |
313 | |
314 | The following modules are currently used by bigint: |
315 | |
316 | Math::BigInt::Lite (for speed, and only if it is loadable) |
317 | Math::BigInt |
318 | |
319 | =head1 EXAMPLES |
320 | |
321 | Some cool command line examples to impress the Python crowd ;) You might want |
322 | to compare them to the results under -Mbignum or -Mbigrat: |
323 | |
324 | perl -Mbigint -le 'print sqrt(33)' |
325 | perl -Mbigint -le 'print 2*255' |
326 | perl -Mbigint -le 'print 4.5+2*255' |
327 | perl -Mbigint -le 'print 3/7 + 5/7 + 8/3' |
328 | perl -Mbigint -le 'print 123->is_odd()' |
329 | perl -Mbigint -le 'print log(2)' |
330 | perl -Mbigint -le 'print 2 ** 0.5' |
331 | perl -Mbigint=a,65 -le 'print 2 ** 0.2' |
332 | |
333 | =head1 LICENSE |
334 | |
335 | This program is free software; you may redistribute it and/or modify it under |
336 | the same terms as Perl itself. |
337 | |
338 | =head1 SEE ALSO |
339 | |
340 | Especially L<bigrat> as in C<perl -Mbigrat -le 'print 1/3+1/4'> and |
341 | L<bignum> as in C<perl -Mbignum -le 'print sqrt(2)'>. |
342 | |
343 | L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well |
344 | as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>. |
345 | |
346 | =head1 AUTHORS |
347 | |
348 | (C) by Tels L<http://bloodgate.com/> in early 2002. |
349 | |
350 | =cut |