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1 | package bigint; |
2 | require 5.005; |
3 | |
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4 | $VERSION = '0.07'; |
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5 | use Exporter; |
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6 | @ISA = qw( Exporter ); |
7 | @EXPORT_OK = qw( ); |
8 | @EXPORT = qw( inf NaN ); |
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9 | |
10 | use strict; |
11 | use overload; |
12 | |
13 | ############################################################################## |
14 | |
15 | # These are all alike, and thus faked by AUTOLOAD |
16 | |
17 | my @faked = qw/round_mode accuracy precision div_scale/; |
18 | use vars qw/$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 $_[0]) |
35 | { |
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36 | return Math::BigInt->$name($_[0]); |
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37 | } |
38 | return Math::BigInt->$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 $float; |
75 | } |
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76 | my ($mis,$miv,$mfv,$es,$ev) = Math::BigInt::_split($float); |
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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 |
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105 | my $lib = ''; |
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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 |
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165 | } |
166 | push @import, 'lib' => $lib if $lib ne ''; |
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167 | # Math::BigInt::Trace or plain Math::BigInt |
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168 | $class->import(@import); |
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169 | |
170 | bigint->accuracy($a) if defined $a; |
171 | bigint->precision($p) if defined $p; |
172 | if ($ver) |
173 | { |
174 | print "bigint\t\t\t v$VERSION\n"; |
175 | print "Math::BigInt::Lite\t v$Math::BigInt::Lite::VERSION\n" if $_lite; |
176 | print "Math::BigInt\t\t v$Math::BigInt::VERSION"; |
177 | my $config = Math::BigInt->config(); |
178 | print " lib => $config->{lib} v$config->{lib_version}\n"; |
179 | exit; |
180 | } |
181 | # we take care of floating point constants, since BigFloat isn't available |
182 | # and BigInt doesn't like them: |
183 | overload::constant float => sub { Math::BigInt->new( _constant(shift) ); }; |
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184 | |
185 | $self->export_to_level(1,$self,@a); # export inf and NaN |
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186 | } |
187 | |
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188 | sub inf () { Math::BigInt->binf(); } |
189 | sub NaN () { Math::BigInt->bnan(); } |
190 | |
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191 | 1; |
192 | |
193 | __END__ |
194 | |
195 | =head1 NAME |
196 | |
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197 | bigint - Transparent BigInteger support for Perl |
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198 | |
199 | =head1 SYNOPSIS |
200 | |
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201 | use bigint; |
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202 | |
203 | $x = 2 + 4.5,"\n"; # BigInt 6 |
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204 | print 2 ** 512,"\n"; # really is what you think it is |
205 | print inf + 42,"\n"; # inf |
206 | print NaN * 7,"\n"; # NaN |
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207 | |
208 | =head1 DESCRIPTION |
209 | |
210 | All operators (including basic math operations) are overloaded. Integer |
211 | constants are created as proper BigInts. |
212 | |
213 | Floating point constants are truncated to integer. All results are also |
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214 | truncated. |
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215 | |
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216 | =head2 Options |
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217 | |
218 | bigint recognizes some options that can be passed while loading it via use. |
219 | The options can (currently) be either a single letter form, or the long form. |
220 | The following options exist: |
221 | |
222 | =over 2 |
223 | |
224 | =item a or accuracy |
225 | |
226 | This sets the accuracy for all math operations. The argument must be greater |
227 | than or equal to zero. See Math::BigInt's bround() function for details. |
228 | |
229 | perl -Mbigint=a,2 -le 'print 12345+1' |
230 | |
231 | =item p or precision |
232 | |
233 | This sets the precision for all math operations. The argument can be any |
234 | integer. Negative values mean a fixed number of digits after the dot, and |
235 | are <B>ignored</B> since all operations happen in integer space. |
236 | A positive value rounds to this digit left from the dot. 0 or 1 mean round to |
237 | integer and are ignore like negative values. |
238 | |
239 | See Math::BigInt's bfround() function for details. |
240 | |
241 | perl -Mbignum=p,5 -le 'print 123456789+123' |
242 | |
243 | =item t or trace |
244 | |
245 | This enables a trace mode and is primarily for debugging bigint or |
246 | Math::BigInt. |
247 | |
248 | =item l or lib |
249 | |
250 | Load a different math lib, see L<MATH LIBRARY>. |
251 | |
252 | perl -Mbigint=l,GMP -e 'print 2 ** 512' |
253 | |
254 | Currently there is no way to specify more than one library on the command |
255 | line. This will be hopefully fixed soon ;) |
256 | |
257 | =item v or version |
258 | |
259 | This prints out the name and version of all modules used and then exits. |
260 | |
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261 | perl -Mbigint=v |
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262 | |
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263 | =head2 Math Library |
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264 | |
265 | Math with the numbers is done (by default) by a module called |
266 | Math::BigInt::Calc. This is equivalent to saying: |
267 | |
268 | use bigint lib => 'Calc'; |
269 | |
270 | You can change this by using: |
271 | |
272 | use bigint lib => 'BitVect'; |
273 | |
274 | The following would first try to find Math::BigInt::Foo, then |
275 | Math::BigInt::Bar, and when this also fails, revert to Math::BigInt::Calc: |
276 | |
277 | use bigint lib => 'Foo,Math::BigInt::Bar'; |
278 | |
279 | Please see respective module documentation for further details. |
280 | |
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281 | =head2 Internal Format |
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282 | |
283 | The numbers are stored as objects, and their internals might change at anytime, |
284 | especially between math operations. The objects also might belong to different |
285 | classes, like Math::BigInt, or Math::BigInt::Lite. Mixing them together, even |
286 | with normal scalars is not extraordinary, but normal and expected. |
287 | |
288 | You should not depend on the internal format, all accesses must go through |
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289 | accessor methods. E.g. looking at $x->{sign} is not a good idea since there |
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290 | is no guaranty that the object in question has such a hash key, nor is a hash |
291 | underneath at all. |
292 | |
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293 | =head2 Sign |
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294 | |
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295 | The sign is either '+', '-', 'NaN', '+inf' or '-inf'. |
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296 | You can access it with the sign() method. |
297 | |
298 | A sign of 'NaN' is used to represent the result when input arguments are not |
299 | numbers or as a result of 0/0. '+inf' and '-inf' represent plus respectively |
300 | minus infinity. You will get '+inf' when dividing a positive number by 0, and |
301 | '-inf' when dividing any negative number by 0. |
302 | |
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303 | =head2 Methods |
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304 | |
305 | Since all numbers are now objects, you can use all functions that are part of |
306 | the BigInt API. You can only use the bxxx() notation, and not the fxxx() |
307 | notation, though. |
308 | |
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309 | =head2 Caveat |
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310 | |
311 | But a warning is in order. When using the following to make a copy of a number, |
312 | only a shallow copy will be made. |
313 | |
314 | $x = 9; $y = $x; |
315 | $x = $y = 7; |
316 | |
317 | Using the copy or the original with overloaded math is okay, e.g. the |
318 | following work: |
319 | |
320 | $x = 9; $y = $x; |
321 | print $x + 1, " ", $y,"\n"; # prints 10 9 |
322 | |
323 | but calling any method that modifies the number directly will result in |
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324 | B<both> the original and the copy being destroyed: |
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325 | |
326 | $x = 9; $y = $x; |
327 | print $x->badd(1), " ", $y,"\n"; # prints 10 10 |
328 | |
329 | $x = 9; $y = $x; |
330 | print $x->binc(1), " ", $y,"\n"; # prints 10 10 |
331 | |
332 | $x = 9; $y = $x; |
333 | print $x->bmul(2), " ", $y,"\n"; # prints 18 18 |
334 | |
335 | Using methods that do not modify, but testthe contents works: |
336 | |
337 | $x = 9; $y = $x; |
338 | $z = 9 if $x->is_zero(); # works fine |
339 | |
340 | See the documentation about the copy constructor and C<=> in overload, as |
341 | well as the documentation in BigInt for further details. |
342 | |
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343 | =head1 MODULES USED |
344 | |
345 | C<bigint> is just a thin wrapper around various modules of the Math::BigInt |
346 | family. Think of it as the head of the family, who runs the shop, and orders |
347 | the others to do the work. |
348 | |
349 | The following modules are currently used by bigint: |
350 | |
351 | Math::BigInt::Lite (for speed, and only if it is loadable) |
352 | Math::BigInt |
353 | |
354 | =head1 EXAMPLES |
355 | |
356 | Some cool command line examples to impress the Python crowd ;) You might want |
357 | to compare them to the results under -Mbignum or -Mbigrat: |
358 | |
359 | perl -Mbigint -le 'print sqrt(33)' |
360 | perl -Mbigint -le 'print 2*255' |
361 | perl -Mbigint -le 'print 4.5+2*255' |
362 | perl -Mbigint -le 'print 3/7 + 5/7 + 8/3' |
363 | perl -Mbigint -le 'print 123->is_odd()' |
364 | perl -Mbigint -le 'print log(2)' |
365 | perl -Mbigint -le 'print 2 ** 0.5' |
366 | perl -Mbigint=a,65 -le 'print 2 ** 0.2' |
367 | |
368 | =head1 LICENSE |
369 | |
370 | This program is free software; you may redistribute it and/or modify it under |
371 | the same terms as Perl itself. |
372 | |
373 | =head1 SEE ALSO |
374 | |
375 | Especially L<bigrat> as in C<perl -Mbigrat -le 'print 1/3+1/4'> and |
376 | L<bignum> as in C<perl -Mbignum -le 'print sqrt(2)'>. |
377 | |
378 | L<Math::BigInt>, L<Math::BigRat> and L<Math::Big> as well |
379 | as L<Math::BigInt::BitVect>, L<Math::BigInt::Pari> and L<Math::BigInt::GMP>. |
380 | |
381 | =head1 AUTHORS |
382 | |
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383 | (C) by Tels L<http://bloodgate.com/> in early 2002 - 2005. |
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384 | |
385 | =cut |