Commit | Line | Data |
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1 | package Math::BigInt::Calc; |
2 | |
3 | use 5.005; |
4 | use strict; |
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5 | # use warnings; # dont use warnings for older Perls |
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6 | |
7 | require Exporter; |
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8 | use vars qw/@ISA $VERSION/; |
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9 | @ISA = qw(Exporter); |
10 | |
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11 | $VERSION = '0.25'; |
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12 | |
13 | # Package to store unsigned big integers in decimal and do math with them |
14 | |
15 | # Internally the numbers are stored in an array with at least 1 element, no |
027dc388 |
16 | # leading zero parts (except the first) and in base 1eX where X is determined |
17 | # automatically at loading time to be the maximum possible value |
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18 | |
19 | # todo: |
20 | # - fully remove funky $# stuff (maybe) |
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21 | |
22 | # USE_MUL: due to problems on certain os (os390, posix-bc) "* 1e-5" is used |
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23 | # instead of "/ 1e5" at some places, (marked with USE_MUL). Other platforms |
24 | # BS2000, some Crays need USE_DIV instead. |
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25 | # The BEGIN block is used to determine which of the two variants gives the |
26 | # correct result. |
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27 | |
28 | ############################################################################## |
29 | # global constants, flags and accessory |
30 | |
31 | # constants for easier life |
32 | my $nan = 'NaN'; |
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33 | my ($MBASE,$BASE,$RBASE,$BASE_LEN,$MAX_VAL,$BASE_LEN2,$BASE_LEN_SMALL); |
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34 | my ($AND_BITS,$XOR_BITS,$OR_BITS); |
35 | my ($AND_MASK,$XOR_MASK,$OR_MASK); |
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36 | my ($LEN_CONVERT); |
ee15d750 |
37 | |
38 | sub _base_len |
39 | { |
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40 | # set/get the BASE_LEN and assorted other, connected values |
41 | # used only be the testsuite, set is used only by the BEGIN block below |
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42 | shift; |
43 | |
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44 | my $b = shift; |
45 | if (defined $b) |
46 | { |
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47 | # find whether we can use mul or div or none in mul()/div() |
48 | # (in last case reduce BASE_LEN_SMALL) |
49 | $BASE_LEN_SMALL = $b+1; |
50 | my $caught = 0; |
51 | while (--$BASE_LEN_SMALL > 5) |
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52 | { |
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53 | $MBASE = int("1e".$BASE_LEN_SMALL); |
54 | $RBASE = abs('1e-'.$BASE_LEN_SMALL); # see USE_MUL |
394e6ffb |
55 | $caught = 0; |
61f5c3f5 |
56 | $caught += 1 if (int($MBASE * $RBASE) != 1); # should be 1 |
57 | $caught += 2 if (int($MBASE / $MBASE) != 1); # should be 1 |
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58 | last if $caught != 3; |
59 | } |
61f5c3f5 |
60 | # BASE_LEN is used for anything else than mul()/div() |
61 | $BASE_LEN = $BASE_LEN_SMALL; |
62 | $BASE_LEN = shift if (defined $_[0]); # one more arg? |
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63 | $BASE = int("1e".$BASE_LEN); |
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64 | |
65 | $BASE_LEN2 = int($BASE_LEN_SMALL / 2); # for mul shortcut |
66 | $MBASE = int("1e".$BASE_LEN_SMALL); |
67 | $RBASE = abs('1e-'.$BASE_LEN_SMALL); # see USE_MUL |
68 | $MAX_VAL = $MBASE-1; |
69 | $LEN_CONVERT = 0; |
70 | $LEN_CONVERT = 1 if $BASE_LEN_SMALL != $BASE_LEN; |
71 | |
72 | #print "BASE_LEN: $BASE_LEN MAX_VAL: $MAX_VAL BASE: $BASE RBASE: $RBASE "; |
73 | #print "BASE_LEN_SMALL: $BASE_LEN_SMALL MBASE: $MBASE\n"; |
74 | |
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75 | if ($caught & 1 != 0) |
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76 | { |
77 | # must USE_MUL |
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78 | *{_mul} = \&_mul_use_mul; |
79 | *{_div} = \&_div_use_mul; |
80 | } |
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81 | else # $caught must be 2, since it can't be 1 nor 3 |
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82 | { |
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83 | # can USE_DIV instead |
84 | *{_mul} = \&_mul_use_div; |
85 | *{_div} = \&_div_use_div; |
86 | } |
87 | } |
61f5c3f5 |
88 | return $BASE_LEN unless wantarray; |
89 | return ($BASE_LEN, $AND_BITS, $XOR_BITS, $OR_BITS, $BASE_LEN_SMALL, $MAX_VAL); |
ee15d750 |
90 | } |
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91 | |
92 | BEGIN |
93 | { |
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94 | # from Daniel Pfeiffer: determine largest group of digits that is precisely |
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95 | # multipliable with itself plus carry |
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96 | # Test now changed to expect the proper pattern, not a result off by 1 or 2 |
97 | my ($e, $num) = 3; # lowest value we will use is 3+1-1 = 3 |
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98 | do |
99 | { |
100 | $num = ('9' x ++$e) + 0; |
394e6ffb |
101 | $num *= $num + 1.0; |
394e6ffb |
102 | } while ("$num" =~ /9{$e}0{$e}/); # must be a certain pattern |
103 | $e--; # last test failed, so retract one step |
104 | # the limits below brush the problems with the test above under the rug: |
105 | # the test should be able to find the proper $e automatically |
106 | $e = 5 if $^O =~ /^uts/; # UTS get's some special treatment |
107 | $e = 5 if $^O =~ /^unicos/; # unicos is also problematic (6 seems to work |
108 | # there, but we play safe) |
109 | $e = 8 if $e > 8; # cap, for VMS, OS/390 and other 64 bit systems |
110 | |
61f5c3f5 |
111 | # determine how many digits fit into an integer and can be safely added |
112 | # together plus carry w/o causing an overflow |
113 | |
114 | # this below detects 15 on a 64 bit system, because after that it becomes |
115 | # 1e16 and not 1000000 :/ I can make it detect 18, but then I get a lot of |
116 | # test failures. Ugh! (Tomake detect 18: uncomment lines marked with *) |
117 | use integer; |
118 | my $bi = 5; # approx. 16 bit |
119 | $num = int('9' x $bi); |
120 | # $num = 99999; # * |
121 | # while ( ($num+$num+1) eq '1' . '9' x $bi) # * |
122 | while ( int($num+$num+1) eq '1' . '9' x $bi) |
123 | { |
124 | $bi++; $num = int('9' x $bi); |
125 | # $bi++; $num *= 10; $num += 9; # * |
126 | } |
127 | $bi--; # back off one step |
128 | # by setting them equal, we ignore the findings and use the default |
129 | # one-size-fits-all approach from former versions |
130 | $bi = $e; # XXX, this should work always |
131 | |
132 | __PACKAGE__->_base_len($e,$bi); # set and store |
394e6ffb |
133 | |
134 | # find out how many bits _and, _or and _xor can take (old default = 16) |
135 | # I don't think anybody has yet 128 bit scalars, so let's play safe. |
394e6ffb |
136 | local $^W = 0; # don't warn about 'nonportable number' |
137 | $AND_BITS = 15; $XOR_BITS = 15; $OR_BITS = 15; |
138 | |
139 | # find max bits, we will not go higher than numberofbits that fit into $BASE |
140 | # to make _and etc simpler (and faster for smaller, slower for large numbers) |
141 | my $max = 16; |
142 | while (2 ** $max < $BASE) { $max++; } |
143 | my ($x,$y,$z); |
144 | do { |
145 | $AND_BITS++; |
146 | $x = oct('0b' . '1' x $AND_BITS); $y = $x & $x; |
147 | $z = (2 ** $AND_BITS) - 1; |
148 | } while ($AND_BITS < $max && $x == $z && $y == $x); |
149 | $AND_BITS --; # retreat one step |
150 | do { |
151 | $XOR_BITS++; |
152 | $x = oct('0b' . '1' x $XOR_BITS); $y = $x ^ 0; |
153 | $z = (2 ** $XOR_BITS) - 1; |
154 | } while ($XOR_BITS < $max && $x == $z && $y == $x); |
155 | $XOR_BITS --; # retreat one step |
156 | do { |
157 | $OR_BITS++; |
158 | $x = oct('0b' . '1' x $OR_BITS); $y = $x | $x; |
159 | $z = (2 ** $OR_BITS) - 1; |
160 | } while ($OR_BITS < $max && $x == $z && $y == $x); |
161 | $OR_BITS --; # retreat one step |
162 | |
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163 | } |
164 | |
0716bf9b |
165 | ############################################################################## |
61f5c3f5 |
166 | # convert between the "small" and the "large" representation |
167 | |
168 | sub _to_large |
169 | { |
170 | # take an array in base $BASE_LEN_SMALL and convert it in-place to $BASE_LEN |
171 | my ($c,$x) = @_; |
172 | |
173 | # print "_to_large $BASE_LEN_SMALL => $BASE_LEN\n"; |
174 | |
175 | return $x if $LEN_CONVERT == 0 || # nothing to converconvertor |
176 | @$x == 1; # only one element => early out |
177 | |
178 | # 12345 67890 12345 67890 contents |
179 | # to 3 2 1 0 index |
180 | # 123456 7890123 4567890 contents |
181 | |
182 | # # faster variant |
183 | # my @d; my $str = ''; |
184 | # my $z = '0' x $BASE_LEN_SMALL; |
185 | # foreach (@$x) |
186 | # { |
187 | # # ... . 04321 . 000321 |
188 | # $str = substr($z.$_,-$BASE_LEN_SMALL,$BASE_LEN_SMALL) . $str; |
189 | # if (length($str) > $BASE_LEN) |
190 | # { |
191 | # push @d, substr($str,-$BASE_LEN,$BASE_LEN); # extract one piece |
192 | # substr($str,-$BASE_LEN,$BASE_LEN) = ''; # remove it |
193 | # } |
194 | # } |
195 | # push @d, $str if $str !~ /^0*$/; # extract last piece |
196 | # @$x = @d; |
197 | # $x->[-1] = int($x->[-1]); # strip leading zero |
198 | # $x; |
199 | |
200 | my $ret = ""; |
201 | my $l = scalar @$x; # number of parts |
202 | $l --; $ret .= int($x->[$l]); $l--; |
203 | my $z = '0' x ($BASE_LEN_SMALL-1); |
204 | while ($l >= 0) |
205 | { |
206 | $ret .= substr($z.$x->[$l],-$BASE_LEN_SMALL); |
207 | $l--; |
208 | } |
209 | my $str = _new($c,\$ret); # make array |
210 | @$x = @$str; # clobber contents of $x |
211 | $x->[-1] = int($x->[-1]); # strip leading zero |
212 | } |
213 | |
214 | sub _to_small |
215 | { |
216 | # take an array in base $BASE_LEN and convert it in-place to $BASE_LEN_SMALL |
217 | my ($c,$x) = @_; |
218 | |
219 | return $x if $LEN_CONVERT == 0; # nothing to do |
220 | return $x if @$x == 1 && length(int($x->[0])) <= $BASE_LEN_SMALL; |
221 | |
222 | my $d = _str($c,$x); |
223 | my $il = length($$d)-1; |
224 | ## this leaves '00000' instead of int 0 and will be corrected after any op |
225 | # clobber contents of $x |
226 | @$x = reverse(unpack("a" . ($il % $BASE_LEN_SMALL+1) |
227 | . ("a$BASE_LEN_SMALL" x ($il / $BASE_LEN_SMALL)), $$d)); |
228 | |
229 | $x->[-1] = int($x->[-1]); # strip leading zero |
230 | } |
231 | |
232 | ############################################################################### |
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233 | |
234 | sub _new |
235 | { |
394e6ffb |
236 | # (ref to string) return ref to num_array |
9393ace2 |
237 | # Convert a number from string format (without sign) to internal base |
238 | # 1ex format. Assumes normalized value as input. |
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239 | my $d = $_[1]; |
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240 | my $il = length($$d)-1; |
241 | # this leaves '00000' instead of int 0 and will be corrected after any op |
242 | [ reverse(unpack("a" . ($il % $BASE_LEN+1) |
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243 | . ("a$BASE_LEN" x ($il / $BASE_LEN)), $$d)) ]; |
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244 | } |
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245 | |
246 | BEGIN |
247 | { |
248 | $AND_MASK = __PACKAGE__->_new( \( 2 ** $AND_BITS )); |
249 | $XOR_MASK = __PACKAGE__->_new( \( 2 ** $XOR_BITS )); |
250 | $OR_MASK = __PACKAGE__->_new( \( 2 ** $OR_BITS )); |
251 | } |
0716bf9b |
252 | |
253 | sub _zero |
254 | { |
255 | # create a zero |
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256 | [ 0 ]; |
0716bf9b |
257 | } |
258 | |
259 | sub _one |
260 | { |
261 | # create a one |
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262 | [ 1 ]; |
0716bf9b |
263 | } |
264 | |
027dc388 |
265 | sub _two |
266 | { |
267 | # create a two (for _pow) |
61f5c3f5 |
268 | [ 2 ]; |
027dc388 |
269 | } |
270 | |
0716bf9b |
271 | sub _copy |
272 | { |
61f5c3f5 |
273 | [ @{$_[1]} ]; |
0716bf9b |
274 | } |
275 | |
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276 | # catch and throw away |
277 | sub import { } |
278 | |
0716bf9b |
279 | ############################################################################## |
280 | # convert back to string and number |
281 | |
282 | sub _str |
283 | { |
284 | # (ref to BINT) return num_str |
285 | # Convert number from internal base 100000 format to string format. |
286 | # internal format is always normalized (no leading zeros, "-0" => "+0") |
574bacfe |
287 | my $ar = $_[1]; |
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288 | my $ret = ""; |
61f5c3f5 |
289 | |
290 | my $l = scalar @$ar; # number of parts |
291 | return $nan if $l < 1; # should not happen |
292 | |
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293 | # handle first one different to strip leading zeros from it (there are no |
294 | # leading zero parts in internal representation) |
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295 | $l --; $ret .= int($ar->[$l]); $l--; |
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296 | # Interestingly, the pre-padd method uses more time |
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297 | # the old grep variant takes longer (14 to 10 sec) |
298 | my $z = '0' x ($BASE_LEN-1); |
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299 | while ($l >= 0) |
300 | { |
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301 | $ret .= substr($z.$ar->[$l],-$BASE_LEN); # fastest way I could think of |
0716bf9b |
302 | $l--; |
303 | } |
61f5c3f5 |
304 | \$ret; |
0716bf9b |
305 | } |
306 | |
307 | sub _num |
308 | { |
309 | # Make a number (scalar int/float) from a BigInt object |
574bacfe |
310 | my $x = $_[1]; |
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311 | return $x->[0] if scalar @$x == 1; # below $BASE |
312 | my $fac = 1; |
313 | my $num = 0; |
314 | foreach (@$x) |
315 | { |
316 | $num += $fac*$_; $fac *= $BASE; |
317 | } |
61f5c3f5 |
318 | $num; |
0716bf9b |
319 | } |
320 | |
321 | ############################################################################## |
322 | # actual math code |
323 | |
324 | sub _add |
325 | { |
326 | # (ref to int_num_array, ref to int_num_array) |
574bacfe |
327 | # routine to add two base 1eX numbers |
0716bf9b |
328 | # stolen from Knuth Vol 2 Algorithm A pg 231 |
b22b3e31 |
329 | # there are separate routines to add and sub as per Knuth pg 233 |
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330 | # This routine clobbers up array x, but not y. |
331 | |
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332 | my ($c,$x,$y) = @_; |
b3abae2a |
333 | |
334 | return $x if (@$y == 1) && $y->[0] == 0; # $x + 0 => $x |
335 | if ((@$x == 1) && $x->[0] == 0) # 0 + $y => $y->copy |
336 | { |
337 | # twice as slow as $x = [ @$y ], but necc. to retain $x as ref :( |
338 | @$x = @$y; return $x; |
339 | } |
0716bf9b |
340 | |
341 | # for each in Y, add Y to X and carry. If after that, something is left in |
342 | # X, foreach in X add carry to X and then return X, carry |
343 | # Trades one "$j++" for having to shift arrays, $j could be made integer |
b22b3e31 |
344 | # but this would impose a limit to number-length of 2**32. |
0716bf9b |
345 | my $i; my $car = 0; my $j = 0; |
346 | for $i (@$y) |
347 | { |
e745a66c |
348 | $x->[$j] -= $BASE if $car = (($x->[$j] += $i + $car) >= $BASE) ? 1 : 0; |
0716bf9b |
349 | $j++; |
350 | } |
351 | while ($car != 0) |
352 | { |
353 | $x->[$j] -= $BASE if $car = (($x->[$j] += $car) >= $BASE) ? 1 : 0; $j++; |
354 | } |
61f5c3f5 |
355 | $x; |
e745a66c |
356 | } |
357 | |
358 | sub _inc |
359 | { |
360 | # (ref to int_num_array, ref to int_num_array) |
361 | # routine to add 1 to a base 1eX numbers |
362 | # This routine clobbers up array x, but not y. |
363 | my ($c,$x) = @_; |
364 | |
365 | for my $i (@$x) |
366 | { |
367 | return $x if (($i += 1) < $BASE); # early out |
61f5c3f5 |
368 | $i = 0; # overflow, next |
e745a66c |
369 | } |
61f5c3f5 |
370 | push @$x,1 if ($x->[-1] == 0); # last overflowed, so extend |
371 | $x; |
e745a66c |
372 | } |
373 | |
374 | sub _dec |
375 | { |
376 | # (ref to int_num_array, ref to int_num_array) |
377 | # routine to add 1 to a base 1eX numbers |
378 | # This routine clobbers up array x, but not y. |
379 | my ($c,$x) = @_; |
380 | |
61f5c3f5 |
381 | my $MAX = $BASE-1; # since MAX_VAL based on MBASE |
e745a66c |
382 | for my $i (@$x) |
383 | { |
384 | last if (($i -= 1) >= 0); # early out |
61f5c3f5 |
385 | $i = $MAX; # overflow, next |
e745a66c |
386 | } |
387 | pop @$x if $x->[-1] == 0 && @$x > 1; # last overflowed (but leave 0) |
61f5c3f5 |
388 | $x; |
0716bf9b |
389 | } |
390 | |
391 | sub _sub |
392 | { |
9393ace2 |
393 | # (ref to int_num_array, ref to int_num_array, swap) |
574bacfe |
394 | # subtract base 1eX numbers -- stolen from Knuth Vol 2 pg 232, $x > $y |
b22b3e31 |
395 | # subtract Y from X (X is always greater/equal!) by modifying x in place |
574bacfe |
396 | my ($c,$sx,$sy,$s) = @_; |
0716bf9b |
397 | |
398 | my $car = 0; my $i; my $j = 0; |
399 | if (!$s) |
400 | { |
401 | #print "case 2\n"; |
402 | for $i (@$sx) |
403 | { |
404 | last unless defined $sy->[$j] || $car; |
0716bf9b |
405 | $i += $BASE if $car = (($i -= ($sy->[$j] || 0) + $car) < 0); $j++; |
0716bf9b |
406 | } |
407 | # might leave leading zeros, so fix that |
394e6ffb |
408 | return __strip_zeros($sx); |
0716bf9b |
409 | } |
394e6ffb |
410 | #print "case 1 (swap)\n"; |
411 | for $i (@$sx) |
0716bf9b |
412 | { |
394e6ffb |
413 | last unless defined $sy->[$j] || $car; |
414 | $sy->[$j] += $BASE |
415 | if $car = (($sy->[$j] = $i-($sy->[$j]||0) - $car) < 0); |
416 | $j++; |
0716bf9b |
417 | } |
394e6ffb |
418 | # might leave leading zeros, so fix that |
419 | __strip_zeros($sy); |
0716bf9b |
420 | } |
421 | |
9393ace2 |
422 | sub _square_use_mul |
423 | { |
424 | # compute $x ** 2 or $x * $x in-place and return $x |
425 | my ($c,$x) = @_; |
426 | |
427 | # From: Handbook of Applied Cryptography by A. Menezes, P. van Oorschot and |
428 | # S. Vanstone., Chapter 14 |
429 | |
430 | #14.16 Algorithm Multiple-precision squaring |
431 | #INPUT: positive integer x = (xt 1 xt 2 ... x1 x0)b. |
432 | #OUTPUT: x * x = x ** 2 in radix b representation. |
433 | #1. For i from 0 to (2t - 1) do: wi <- 0. |
434 | #2. For i from 0 to (t - 1) do the following: |
435 | # 2.1 (uv)b w2i + xi * xi, w2i v, c u. |
436 | # 2.2 For j from (i + 1)to (t - 1) do the following: |
437 | # (uv)b <- wi+j + 2*xj * xi + c, wi+j <- v, c <- u. |
438 | # 2.3 wi+t <- u. |
439 | #3. Return((w2t-1 w2t-2 ... w1 w0)b). |
440 | |
441 | # # Note: That description is crap. Half of the symbols are not explained or |
442 | # # used with out beeing set. |
443 | # my $t = scalar @$x; # count |
444 | # my ($c,$i,$j); |
445 | # for ($i = 0; $i < $t; $i++) |
446 | # { |
447 | # $x->[$i] = $x->[$i*2] + $x[$i]*$x[$i]; |
448 | # $x->[$i*2] = $x[$i]; $c = $x[$i]; |
449 | # for ($j = $i+1; $j < $t; $j++) |
450 | # { |
451 | # $x->[$i] = $x->[$i+$j] + 2 * $x->[$i] * $x->[$j]; |
452 | # $x->[$i+$j] = $x[$j]; $c = $x[$i]; |
453 | # } |
454 | # $x->[$i+$t] = $x[$i]; |
455 | # } |
456 | $x; |
457 | } |
458 | |
ee15d750 |
459 | sub _mul_use_mul |
0716bf9b |
460 | { |
9393ace2 |
461 | # (ref to int_num_array, ref to int_num_array) |
0716bf9b |
462 | # multiply two numbers in internal representation |
b22b3e31 |
463 | # modifies first arg, second need not be different from first |
574bacfe |
464 | my ($c,$xv,$yv) = @_; |
dccbb853 |
465 | |
b3abae2a |
466 | # shortcut for two very short numbers (improved by Nathan Zook) |
61f5c3f5 |
467 | # works also if xv and yv are the same reference |
b3abae2a |
468 | if ((@$xv == 1) && (@$yv == 1)) |
469 | { |
470 | if (($xv->[0] *= $yv->[0]) >= $MBASE) |
471 | { |
472 | $xv->[0] = $xv->[0] - ($xv->[1] = int($xv->[0] * $RBASE)) * $MBASE; |
473 | }; |
474 | return $xv; |
475 | } |
476 | # shortcut for result == 0 |
477 | if ( ((@$xv == 1) && ($xv->[0] == 0)) || |
478 | ((@$yv == 1) && ($yv->[0] == 0)) ) |
479 | { |
480 | @$xv = (0); |
481 | return $xv; |
482 | } |
483 | |
0716bf9b |
484 | # since multiplying $x with $x fails, make copy in this case |
574bacfe |
485 | $yv = [@$xv] if "$xv" eq "$yv"; # same references? |
9393ace2 |
486 | # since multiplying $x with $x would fail here, use the faster squaring |
487 | # return _square($c,$xv) if "$xv" eq "$yv"; # same reference? |
488 | |
61f5c3f5 |
489 | if ($LEN_CONVERT != 0) |
490 | { |
491 | $c->_to_small($xv); $c->_to_small($yv); |
492 | } |
493 | |
494 | my @prod = (); my ($prod,$car,$cty,$xi,$yi); |
495 | |
0716bf9b |
496 | for $xi (@$xv) |
497 | { |
498 | $car = 0; $cty = 0; |
574bacfe |
499 | |
500 | # slow variant |
501 | # for $yi (@$yv) |
502 | # { |
503 | # $prod = $xi * $yi + ($prod[$cty] || 0) + $car; |
504 | # $prod[$cty++] = |
61f5c3f5 |
505 | # $prod - ($car = int($prod * RBASE)) * $MBASE; # see USE_MUL |
574bacfe |
506 | # } |
507 | # $prod[$cty] += $car if $car; # need really to check for 0? |
508 | # $xi = shift @prod; |
509 | |
510 | # faster variant |
511 | # looping through this if $xi == 0 is silly - so optimize it away! |
512 | $xi = (shift @prod || 0), next if $xi == 0; |
0716bf9b |
513 | for $yi (@$yv) |
514 | { |
515 | $prod = $xi * $yi + ($prod[$cty] || 0) + $car; |
574bacfe |
516 | ## this is actually a tad slower |
517 | ## $prod = $prod[$cty]; $prod += ($car + $xi * $yi); # no ||0 here |
0716bf9b |
518 | $prod[$cty++] = |
61f5c3f5 |
519 | $prod - ($car = int($prod * $RBASE)) * $MBASE; # see USE_MUL |
0716bf9b |
520 | } |
521 | $prod[$cty] += $car if $car; # need really to check for 0? |
027dc388 |
522 | $xi = shift @prod || 0; # || 0 makes v5.005_3 happy |
0716bf9b |
523 | } |
0716bf9b |
524 | push @$xv, @prod; |
61f5c3f5 |
525 | if ($LEN_CONVERT != 0) |
526 | { |
527 | $c->_to_large($yv); |
528 | $c->_to_large($xv); |
529 | } |
530 | else |
531 | { |
532 | __strip_zeros($xv); |
533 | } |
534 | $xv; |
0716bf9b |
535 | } |
536 | |
ee15d750 |
537 | sub _mul_use_div |
538 | { |
9393ace2 |
539 | # (ref to int_num_array, ref to int_num_array) |
ee15d750 |
540 | # multiply two numbers in internal representation |
541 | # modifies first arg, second need not be different from first |
542 | my ($c,$xv,$yv) = @_; |
543 | |
b3abae2a |
544 | # shortcut for two very short numbers (improved by Nathan Zook) |
61f5c3f5 |
545 | # works also if xv and yv are the same reference |
b3abae2a |
546 | if ((@$xv == 1) && (@$yv == 1)) |
547 | { |
548 | if (($xv->[0] *= $yv->[0]) >= $MBASE) |
549 | { |
550 | $xv->[0] = |
551 | $xv->[0] - ($xv->[1] = int($xv->[0] / $MBASE)) * $MBASE; |
552 | }; |
553 | return $xv; |
554 | } |
555 | # shortcut for result == 0 |
556 | if ( ((@$xv == 1) && ($xv->[0] == 0)) || |
557 | ((@$yv == 1) && ($yv->[0] == 0)) ) |
558 | { |
559 | @$xv = (0); |
560 | return $xv; |
561 | } |
562 | |
61f5c3f5 |
563 | |
ee15d750 |
564 | # since multiplying $x with $x fails, make copy in this case |
565 | $yv = [@$xv] if "$xv" eq "$yv"; # same references? |
9393ace2 |
566 | # since multiplying $x with $x would fail here, use the faster squaring |
567 | # return _square($c,$xv) if "$xv" eq "$yv"; # same reference? |
568 | |
61f5c3f5 |
569 | if ($LEN_CONVERT != 0) |
570 | { |
571 | $c->_to_small($xv); $c->_to_small($yv); |
572 | } |
573 | |
574 | my @prod = (); my ($prod,$car,$cty,$xi,$yi); |
ee15d750 |
575 | for $xi (@$xv) |
576 | { |
577 | $car = 0; $cty = 0; |
578 | # looping through this if $xi == 0 is silly - so optimize it away! |
579 | $xi = (shift @prod || 0), next if $xi == 0; |
580 | for $yi (@$yv) |
581 | { |
582 | $prod = $xi * $yi + ($prod[$cty] || 0) + $car; |
583 | $prod[$cty++] = |
61f5c3f5 |
584 | $prod - ($car = int($prod / $MBASE)) * $MBASE; |
ee15d750 |
585 | } |
586 | $prod[$cty] += $car if $car; # need really to check for 0? |
027dc388 |
587 | $xi = shift @prod || 0; # || 0 makes v5.005_3 happy |
ee15d750 |
588 | } |
589 | push @$xv, @prod; |
61f5c3f5 |
590 | if ($LEN_CONVERT != 0) |
591 | { |
592 | $c->_to_large($yv); |
593 | $c->_to_large($xv); |
594 | } |
595 | else |
596 | { |
597 | __strip_zeros($xv); |
598 | } |
599 | $xv; |
ee15d750 |
600 | } |
601 | |
602 | sub _div_use_mul |
0716bf9b |
603 | { |
b22b3e31 |
604 | # ref to array, ref to array, modify first array and return remainder if |
0716bf9b |
605 | # in list context |
574bacfe |
606 | my ($c,$x,$yorg) = @_; |
0716bf9b |
607 | |
61f5c3f5 |
608 | if (@$x == 1 && @$yorg == 1) |
609 | { |
13a12e00 |
610 | # shortcut, $yorg and $x are two small numbers |
61f5c3f5 |
611 | if (wantarray) |
612 | { |
613 | my $r = [ $x->[0] % $yorg->[0] ]; |
614 | $x->[0] = int($x->[0] / $yorg->[0]); |
615 | return ($x,$r); |
616 | } |
617 | else |
618 | { |
619 | $x->[0] = int($x->[0] / $yorg->[0]); |
620 | return $x; |
621 | } |
622 | } |
28df3e88 |
623 | if (@$yorg == 1) |
624 | { |
625 | my $rem; |
626 | $rem = _mod($c,[ @$x ],$yorg) if wantarray; |
13a12e00 |
627 | |
28df3e88 |
628 | # shortcut, $y is < $BASE |
629 | my $j = scalar @$x; my $r = 0; |
630 | my $y = $yorg->[0]; my $b; |
631 | while ($j-- > 0) |
632 | { |
633 | $b = $r * $MBASE + $x->[$j]; |
634 | $x->[$j] = int($b/$y); |
635 | $r = $b % $y; |
636 | } |
637 | pop @$x if @$x > 1 && $x->[-1] == 0; # splice up a leading zero |
638 | return ($x,$rem) if wantarray; |
639 | return $x; |
640 | } |
0716bf9b |
641 | |
0716bf9b |
642 | my $y = [ @$yorg ]; |
61f5c3f5 |
643 | if ($LEN_CONVERT != 0) |
644 | { |
645 | $c->_to_small($x); $c->_to_small($y); |
646 | } |
647 | |
648 | my ($car,$bar,$prd,$dd,$xi,$yi,@q,$v2,$v1,@d,$tmp,$q,$u2,$u1,$u0); |
649 | |
650 | $car = $bar = $prd = 0; |
651 | if (($dd = int($MBASE/($y->[-1]+1))) != 1) |
0716bf9b |
652 | { |
653 | for $xi (@$x) |
654 | { |
655 | $xi = $xi * $dd + $car; |
61f5c3f5 |
656 | $xi -= ($car = int($xi * $RBASE)) * $MBASE; # see USE_MUL |
0716bf9b |
657 | } |
658 | push(@$x, $car); $car = 0; |
659 | for $yi (@$y) |
660 | { |
661 | $yi = $yi * $dd + $car; |
61f5c3f5 |
662 | $yi -= ($car = int($yi * $RBASE)) * $MBASE; # see USE_MUL |
0716bf9b |
663 | } |
664 | } |
665 | else |
666 | { |
667 | push(@$x, 0); |
668 | } |
669 | @q = (); ($v2,$v1) = @$y[-2,-1]; |
670 | $v2 = 0 unless $v2; |
671 | while ($#$x > $#$y) |
672 | { |
673 | ($u2,$u1,$u0) = @$x[-3..-1]; |
674 | $u2 = 0 unless $u2; |
675 | #warn "oups v1 is 0, u0: $u0 $y->[-2] $y->[-1] l ",scalar @$y,"\n" |
676 | # if $v1 == 0; |
61f5c3f5 |
677 | $q = (($u0 == $v1) ? $MAX_VAL : int(($u0*$MBASE+$u1)/$v1)); |
678 | --$q while ($v2*$q > ($u0*$MBASE+$u1-$q*$v1)*$MBASE+$u2); |
0716bf9b |
679 | if ($q) |
680 | { |
681 | ($car, $bar) = (0,0); |
682 | for ($yi = 0, $xi = $#$x-$#$y-1; $yi <= $#$y; ++$yi,++$xi) |
683 | { |
684 | $prd = $q * $y->[$yi] + $car; |
61f5c3f5 |
685 | $prd -= ($car = int($prd * $RBASE)) * $MBASE; # see USE_MUL |
686 | $x->[$xi] += $MBASE if ($bar = (($x->[$xi] -= $prd + $bar) < 0)); |
0716bf9b |
687 | } |
688 | if ($x->[-1] < $car + $bar) |
689 | { |
690 | $car = 0; --$q; |
691 | for ($yi = 0, $xi = $#$x-$#$y-1; $yi <= $#$y; ++$yi,++$xi) |
692 | { |
61f5c3f5 |
693 | $x->[$xi] -= $MBASE |
694 | if ($car = (($x->[$xi] += $y->[$yi] + $car) > $MBASE)); |
0716bf9b |
695 | } |
696 | } |
697 | } |
698 | pop(@$x); unshift(@q, $q); |
699 | } |
700 | if (wantarray) |
701 | { |
702 | @d = (); |
703 | if ($dd != 1) |
704 | { |
705 | $car = 0; |
706 | for $xi (reverse @$x) |
707 | { |
61f5c3f5 |
708 | $prd = $car * $MBASE + $xi; |
0716bf9b |
709 | $car = $prd - ($tmp = int($prd / $dd)) * $dd; # see USE_MUL |
710 | unshift(@d, $tmp); |
711 | } |
712 | } |
713 | else |
714 | { |
715 | @d = @$x; |
716 | } |
717 | @$x = @q; |
61f5c3f5 |
718 | my $d = \@d; |
719 | if ($LEN_CONVERT != 0) |
720 | { |
721 | $c->_to_large($x); $c->_to_large($d); |
722 | } |
723 | else |
724 | { |
725 | __strip_zeros($x); |
726 | __strip_zeros($d); |
727 | } |
728 | return ($x,$d); |
0716bf9b |
729 | } |
730 | @$x = @q; |
61f5c3f5 |
731 | if ($LEN_CONVERT != 0) |
732 | { |
733 | $c->_to_large($x); |
734 | } |
735 | else |
736 | { |
737 | __strip_zeros($x); |
738 | } |
739 | $x; |
0716bf9b |
740 | } |
741 | |
ee15d750 |
742 | sub _div_use_div |
743 | { |
744 | # ref to array, ref to array, modify first array and return remainder if |
745 | # in list context |
ee15d750 |
746 | my ($c,$x,$yorg) = @_; |
ee15d750 |
747 | |
61f5c3f5 |
748 | if (@$x == 1 && @$yorg == 1) |
749 | { |
13a12e00 |
750 | # shortcut, $yorg and $x are two small numbers |
61f5c3f5 |
751 | if (wantarray) |
752 | { |
753 | my $r = [ $x->[0] % $yorg->[0] ]; |
754 | $x->[0] = int($x->[0] / $yorg->[0]); |
755 | return ($x,$r); |
756 | } |
757 | else |
758 | { |
759 | $x->[0] = int($x->[0] / $yorg->[0]); |
760 | return $x; |
761 | } |
762 | } |
28df3e88 |
763 | if (@$yorg == 1) |
764 | { |
765 | my $rem; |
766 | $rem = _mod($c,[ @$x ],$yorg) if wantarray; |
767 | |
768 | # shortcut, $y is < $BASE |
769 | my $j = scalar @$x; my $r = 0; |
770 | my $y = $yorg->[0]; my $b; |
771 | while ($j-- > 0) |
772 | { |
773 | $b = $r * $MBASE + $x->[$j]; |
774 | $x->[$j] = int($b/$y); |
775 | $r = $b % $y; |
776 | } |
777 | pop @$x if @$x > 1 && $x->[-1] == 0; # splice up a leading zero |
778 | return ($x,$rem) if wantarray; |
779 | return $x; |
780 | } |
ee15d750 |
781 | |
ee15d750 |
782 | my $y = [ @$yorg ]; |
61f5c3f5 |
783 | if ($LEN_CONVERT != 0) |
784 | { |
785 | $c->_to_small($x); $c->_to_small($y); |
786 | } |
787 | |
788 | my ($car,$bar,$prd,$dd,$xi,$yi,@q,$v2,$v1,@d,$tmp,$q,$u2,$u1,$u0); |
789 | |
790 | $car = $bar = $prd = 0; |
791 | if (($dd = int($MBASE/($y->[-1]+1))) != 1) |
ee15d750 |
792 | { |
793 | for $xi (@$x) |
794 | { |
795 | $xi = $xi * $dd + $car; |
61f5c3f5 |
796 | $xi -= ($car = int($xi / $MBASE)) * $MBASE; |
ee15d750 |
797 | } |
798 | push(@$x, $car); $car = 0; |
799 | for $yi (@$y) |
800 | { |
801 | $yi = $yi * $dd + $car; |
61f5c3f5 |
802 | $yi -= ($car = int($yi / $MBASE)) * $MBASE; |
ee15d750 |
803 | } |
804 | } |
805 | else |
806 | { |
807 | push(@$x, 0); |
808 | } |
809 | @q = (); ($v2,$v1) = @$y[-2,-1]; |
810 | $v2 = 0 unless $v2; |
811 | while ($#$x > $#$y) |
812 | { |
813 | ($u2,$u1,$u0) = @$x[-3..-1]; |
814 | $u2 = 0 unless $u2; |
815 | #warn "oups v1 is 0, u0: $u0 $y->[-2] $y->[-1] l ",scalar @$y,"\n" |
816 | # if $v1 == 0; |
61f5c3f5 |
817 | $q = (($u0 == $v1) ? $MAX_VAL : int(($u0*$MBASE+$u1)/$v1)); |
818 | --$q while ($v2*$q > ($u0*$MBASE+$u1-$q*$v1)*$MBASE+$u2); |
ee15d750 |
819 | if ($q) |
820 | { |
821 | ($car, $bar) = (0,0); |
822 | for ($yi = 0, $xi = $#$x-$#$y-1; $yi <= $#$y; ++$yi,++$xi) |
823 | { |
824 | $prd = $q * $y->[$yi] + $car; |
61f5c3f5 |
825 | $prd -= ($car = int($prd / $MBASE)) * $MBASE; |
826 | $x->[$xi] += $MBASE if ($bar = (($x->[$xi] -= $prd + $bar) < 0)); |
ee15d750 |
827 | } |
828 | if ($x->[-1] < $car + $bar) |
829 | { |
830 | $car = 0; --$q; |
831 | for ($yi = 0, $xi = $#$x-$#$y-1; $yi <= $#$y; ++$yi,++$xi) |
832 | { |
61f5c3f5 |
833 | $x->[$xi] -= $MBASE |
834 | if ($car = (($x->[$xi] += $y->[$yi] + $car) > $MBASE)); |
ee15d750 |
835 | } |
836 | } |
837 | } |
61f5c3f5 |
838 | pop(@$x); unshift(@q, $q); |
ee15d750 |
839 | } |
840 | if (wantarray) |
841 | { |
842 | @d = (); |
843 | if ($dd != 1) |
844 | { |
845 | $car = 0; |
846 | for $xi (reverse @$x) |
847 | { |
61f5c3f5 |
848 | $prd = $car * $MBASE + $xi; |
ee15d750 |
849 | $car = $prd - ($tmp = int($prd / $dd)) * $dd; |
850 | unshift(@d, $tmp); |
851 | } |
852 | } |
853 | else |
854 | { |
855 | @d = @$x; |
856 | } |
857 | @$x = @q; |
61f5c3f5 |
858 | my $d = \@d; |
859 | if ($LEN_CONVERT != 0) |
860 | { |
861 | $c->_to_large($x); $c->_to_large($d); |
862 | } |
863 | else |
864 | { |
865 | __strip_zeros($x); |
866 | __strip_zeros($d); |
867 | } |
868 | return ($x,$d); |
ee15d750 |
869 | } |
870 | @$x = @q; |
61f5c3f5 |
871 | if ($LEN_CONVERT != 0) |
872 | { |
873 | $c->_to_large($x); |
874 | } |
875 | else |
876 | { |
877 | __strip_zeros($x); |
878 | } |
879 | $x; |
ee15d750 |
880 | } |
881 | |
394e6ffb |
882 | ############################################################################## |
883 | # testing |
884 | |
885 | sub _acmp |
886 | { |
887 | # internal absolute post-normalized compare (ignore signs) |
888 | # ref to array, ref to array, return <0, 0, >0 |
889 | # arrays must have at least one entry; this is not checked for |
890 | |
891 | my ($c,$cx,$cy) = @_; |
892 | |
61f5c3f5 |
893 | # fast comp based on array elements |
394e6ffb |
894 | my $lxy = scalar @$cx - scalar @$cy; |
895 | return -1 if $lxy < 0; # already differs, ret |
896 | return 1 if $lxy > 0; # ditto |
897 | |
898 | # now calculate length based on digits, not parts |
899 | $lxy = _len($c,$cx) - _len($c,$cy); # difference |
900 | return -1 if $lxy < 0; |
901 | return 1 if $lxy > 0; |
902 | |
903 | # hm, same lengths, but same contents? |
904 | my $i = 0; my $a; |
905 | # first way takes 5.49 sec instead of 4.87, but has the early out advantage |
906 | # so grep is slightly faster, but more inflexible. hm. $_ instead of $k |
907 | # yields 5.6 instead of 5.5 sec huh? |
908 | # manual way (abort if unequal, good for early ne) |
909 | my $j = scalar @$cx - 1; |
910 | while ($j >= 0) |
9393ace2 |
911 | { |
912 | last if ($a = $cx->[$j] - $cy->[$j]); $j--; |
913 | } |
914 | # my $j = scalar @$cx; |
915 | # while (--$j >= 0) |
916 | # { |
917 | # last if ($a = $cx->[$j] - $cy->[$j]); |
918 | # } |
394e6ffb |
919 | return 1 if $a > 0; |
920 | return -1 if $a < 0; |
61f5c3f5 |
921 | 0; # equal |
922 | |
394e6ffb |
923 | # while it early aborts, it is even slower than the manual variant |
924 | #grep { return $a if ($a = $_ - $cy->[$i++]); } @$cx; |
925 | # grep way, go trough all (bad for early ne) |
926 | #grep { $a = $_ - $cy->[$i++]; } @$cx; |
927 | #return $a; |
928 | } |
929 | |
930 | sub _len |
931 | { |
932 | # compute number of digits in bigint, minus the sign |
933 | |
934 | # int() because add/sub sometimes leaves strings (like '00005') instead of |
935 | # '5' in this place, thus causing length() to report wrong length |
936 | my $cx = $_[1]; |
937 | |
938 | return (@$cx-1)*$BASE_LEN+length(int($cx->[-1])); |
939 | } |
940 | |
941 | sub _digit |
942 | { |
943 | # return the nth digit, negative values count backward |
944 | # zero is rightmost, so _digit(123,0) will give 3 |
945 | my ($c,$x,$n) = @_; |
946 | |
947 | my $len = _len('',$x); |
948 | |
949 | $n = $len+$n if $n < 0; # -1 last, -2 second-to-last |
950 | $n = abs($n); # if negative was too big |
951 | $len--; $n = $len if $n > $len; # n to big? |
952 | |
953 | my $elem = int($n / $BASE_LEN); # which array element |
954 | my $digit = $n % $BASE_LEN; # which digit in this element |
955 | $elem = '0000'.@$x[$elem]; # get element padded with 0's |
956 | return substr($elem,-$digit-1,1); |
957 | } |
958 | |
959 | sub _zeros |
960 | { |
961 | # return amount of trailing zeros in decimal |
962 | # check each array elem in _m for having 0 at end as long as elem == 0 |
963 | # Upon finding a elem != 0, stop |
964 | my $x = $_[1]; |
965 | my $zeros = 0; my $elem; |
966 | foreach my $e (@$x) |
967 | { |
968 | if ($e != 0) |
969 | { |
970 | $elem = "$e"; # preserve x |
971 | $elem =~ s/.*?(0*$)/$1/; # strip anything not zero |
972 | $zeros *= $BASE_LEN; # elems * 5 |
61f5c3f5 |
973 | $zeros += length($elem); # count trailing zeros |
394e6ffb |
974 | last; # early out |
975 | } |
976 | $zeros ++; # real else branch: 50% slower! |
977 | } |
61f5c3f5 |
978 | $zeros; |
394e6ffb |
979 | } |
980 | |
981 | ############################################################################## |
982 | # _is_* routines |
983 | |
984 | sub _is_zero |
985 | { |
986 | # return true if arg (BINT or num_str) is zero (array '+', '0') |
987 | my $x = $_[1]; |
61f5c3f5 |
988 | |
989 | (((scalar @$x == 1) && ($x->[0] == 0))) <=> 0; |
394e6ffb |
990 | } |
991 | |
992 | sub _is_even |
993 | { |
994 | # return true if arg (BINT or num_str) is even |
995 | my $x = $_[1]; |
61f5c3f5 |
996 | (!($x->[0] & 1)) <=> 0; |
394e6ffb |
997 | } |
998 | |
999 | sub _is_odd |
1000 | { |
1001 | # return true if arg (BINT or num_str) is even |
1002 | my $x = $_[1]; |
61f5c3f5 |
1003 | |
1004 | (($x->[0] & 1)) <=> 0; |
394e6ffb |
1005 | } |
1006 | |
1007 | sub _is_one |
1008 | { |
1009 | # return true if arg (BINT or num_str) is one (array '+', '1') |
1010 | my $x = $_[1]; |
61f5c3f5 |
1011 | |
1012 | (scalar @$x == 1) && ($x->[0] == 1) <=> 0; |
394e6ffb |
1013 | } |
1014 | |
1015 | sub __strip_zeros |
1016 | { |
1017 | # internal normalization function that strips leading zeros from the array |
1018 | # args: ref to array |
1019 | my $s = shift; |
1020 | |
1021 | my $cnt = scalar @$s; # get count of parts |
1022 | my $i = $cnt-1; |
1023 | push @$s,0 if $i < 0; # div might return empty results, so fix it |
1024 | |
61f5c3f5 |
1025 | return $s if @$s == 1; # early out |
1026 | |
394e6ffb |
1027 | #print "strip: cnt $cnt i $i\n"; |
1028 | # '0', '3', '4', '0', '0', |
1029 | # 0 1 2 3 4 |
1030 | # cnt = 5, i = 4 |
1031 | # i = 4 |
1032 | # i = 3 |
1033 | # => fcnt = cnt - i (5-2 => 3, cnt => 5-1 = 4, throw away from 4th pos) |
1034 | # >= 1: skip first part (this can be zero) |
1035 | while ($i > 0) { last if $s->[$i] != 0; $i--; } |
1036 | $i++; splice @$s,$i if ($i < $cnt); # $i cant be 0 |
1037 | $s; |
1038 | } |
1039 | |
1040 | ############################################################################### |
1041 | # check routine to test internal state of corruptions |
1042 | |
1043 | sub _check |
1044 | { |
1045 | # used by the test suite |
1046 | my $x = $_[1]; |
1047 | |
1048 | return "$x is not a reference" if !ref($x); |
1049 | |
1050 | # are all parts are valid? |
1051 | my $i = 0; my $j = scalar @$x; my ($e,$try); |
1052 | while ($i < $j) |
1053 | { |
1054 | $e = $x->[$i]; $e = 'undef' unless defined $e; |
1055 | $try = '=~ /^[\+]?[0-9]+\$/; '."($x, $e)"; |
1056 | last if $e !~ /^[+]?[0-9]+$/; |
1057 | $try = '=~ /^[\+]?[0-9]+\$/; '."($x, $e) (stringify)"; |
1058 | last if "$e" !~ /^[+]?[0-9]+$/; |
1059 | $try = '=~ /^[\+]?[0-9]+\$/; '."($x, $e) (cat-stringify)"; |
1060 | last if '' . "$e" !~ /^[+]?[0-9]+$/; |
1061 | $try = ' < 0 || >= $BASE; '."($x, $e)"; |
1062 | last if $e <0 || $e >= $BASE; |
1063 | # this test is disabled, since new/bnorm and certain ops (like early out |
1064 | # in add/sub) are allowed/expected to leave '00000' in some elements |
1065 | #$try = '=~ /^00+/; '."($x, $e)"; |
1066 | #last if $e =~ /^00+/; |
1067 | $i++; |
1068 | } |
1069 | return "Illegal part '$e' at pos $i (tested: $try)" if $i < $j; |
1070 | return 0; |
1071 | } |
1072 | |
1073 | |
1074 | ############################################################################### |
1075 | ############################################################################### |
1076 | # some optional routines to make BigInt faster |
1077 | |
dccbb853 |
1078 | sub _mod |
1079 | { |
1080 | # if possible, use mod shortcut |
1081 | my ($c,$x,$yo) = @_; |
1082 | |
1083 | # slow way since $y to big |
1084 | if (scalar @$yo > 1) |
1085 | { |
1086 | my ($xo,$rem) = _div($c,$x,$yo); |
1087 | return $rem; |
1088 | } |
1089 | my $y = $yo->[0]; |
027dc388 |
1090 | # both are single element arrays |
dccbb853 |
1091 | if (scalar @$x == 1) |
1092 | { |
1093 | $x->[0] %= $y; |
1094 | return $x; |
1095 | } |
1096 | |
61f5c3f5 |
1097 | # @y is single element, but @x has more than one |
dccbb853 |
1098 | my $b = $BASE % $y; |
1099 | if ($b == 0) |
1100 | { |
1101 | # when BASE % Y == 0 then (B * BASE) % Y == 0 |
1102 | # (B * BASE) % $y + A % Y => A % Y |
1103 | # so need to consider only last element: O(1) |
1104 | $x->[0] %= $y; |
1105 | } |
027dc388 |
1106 | elsif ($b == 1) |
1107 | { |
28df3e88 |
1108 | # else need to go trough all elements: O(N), but loop is a bit simplified |
027dc388 |
1109 | my $r = 0; |
1110 | foreach (@$x) |
1111 | { |
28df3e88 |
1112 | $r = ($r + $_) % $y; # not much faster, but heh... |
1113 | #$r += $_ % $y; $r %= $y; |
027dc388 |
1114 | } |
1115 | $r = 0 if $r == $y; |
1116 | $x->[0] = $r; |
1117 | } |
dccbb853 |
1118 | else |
1119 | { |
027dc388 |
1120 | # else need to go trough all elements: O(N) |
1121 | my $r = 0; my $bm = 1; |
1122 | foreach (@$x) |
1123 | { |
28df3e88 |
1124 | $r = ($_ * $bm + $r) % $y; |
1125 | $bm = ($bm * $b) % $y; |
1126 | |
1127 | #$r += ($_ % $y) * $bm; |
1128 | #$bm *= $b; |
1129 | #$bm %= $y; |
1130 | #$r %= $y; |
027dc388 |
1131 | } |
1132 | $r = 0 if $r == $y; |
1133 | $x->[0] = $r; |
dccbb853 |
1134 | } |
1135 | splice (@$x,1); |
61f5c3f5 |
1136 | $x; |
dccbb853 |
1137 | } |
1138 | |
0716bf9b |
1139 | ############################################################################## |
574bacfe |
1140 | # shifts |
1141 | |
1142 | sub _rsft |
1143 | { |
1144 | my ($c,$x,$y,$n) = @_; |
1145 | |
1146 | if ($n != 10) |
1147 | { |
61f5c3f5 |
1148 | $n = _new($c,\$n); return _div($c,$x, _pow($c,$n,$y)); |
1149 | } |
1150 | |
1151 | # shortcut (faster) for shifting by 10) |
1152 | # multiples of $BASE_LEN |
1153 | my $dst = 0; # destination |
1154 | my $src = _num($c,$y); # as normal int |
1155 | my $rem = $src % $BASE_LEN; # remainder to shift |
1156 | $src = int($src / $BASE_LEN); # source |
1157 | if ($rem == 0) |
1158 | { |
1159 | splice (@$x,0,$src); # even faster, 38.4 => 39.3 |
574bacfe |
1160 | } |
1161 | else |
1162 | { |
61f5c3f5 |
1163 | my $len = scalar @$x - $src; # elems to go |
1164 | my $vd; my $z = '0'x $BASE_LEN; |
1165 | $x->[scalar @$x] = 0; # avoid || 0 test inside loop |
1166 | while ($dst < $len) |
574bacfe |
1167 | { |
61f5c3f5 |
1168 | $vd = $z.$x->[$src]; |
1169 | $vd = substr($vd,-$BASE_LEN,$BASE_LEN-$rem); |
1170 | $src++; |
1171 | $vd = substr($z.$x->[$src],-$rem,$rem) . $vd; |
1172 | $vd = substr($vd,-$BASE_LEN,$BASE_LEN) if length($vd) > $BASE_LEN; |
1173 | $x->[$dst] = int($vd); |
1174 | $dst++; |
574bacfe |
1175 | } |
61f5c3f5 |
1176 | splice (@$x,$dst) if $dst > 0; # kill left-over array elems |
1177 | pop @$x if $x->[-1] == 0; # kill last element if 0 |
1178 | } # else rem == 0 |
574bacfe |
1179 | $x; |
1180 | } |
1181 | |
1182 | sub _lsft |
1183 | { |
1184 | my ($c,$x,$y,$n) = @_; |
1185 | |
1186 | if ($n != 10) |
1187 | { |
61f5c3f5 |
1188 | $n = _new($c,\$n); return _mul($c,$x, _pow($c,$n,$y)); |
574bacfe |
1189 | } |
61f5c3f5 |
1190 | |
1191 | # shortcut (faster) for shifting by 10) since we are in base 10eX |
1192 | # multiples of $BASE_LEN: |
1193 | my $src = scalar @$x; # source |
1194 | my $len = _num($c,$y); # shift-len as normal int |
1195 | my $rem = $len % $BASE_LEN; # remainder to shift |
1196 | my $dst = $src + int($len/$BASE_LEN); # destination |
1197 | my $vd; # further speedup |
1198 | $x->[$src] = 0; # avoid first ||0 for speed |
1199 | my $z = '0' x $BASE_LEN; |
1200 | while ($src >= 0) |
574bacfe |
1201 | { |
61f5c3f5 |
1202 | $vd = $x->[$src]; $vd = $z.$vd; |
1203 | $vd = substr($vd,-$BASE_LEN+$rem,$BASE_LEN-$rem); |
1204 | $vd .= $src > 0 ? substr($z.$x->[$src-1],-$BASE_LEN,$rem) : '0' x $rem; |
1205 | $vd = substr($vd,-$BASE_LEN,$BASE_LEN) if length($vd) > $BASE_LEN; |
1206 | $x->[$dst] = int($vd); |
1207 | $dst--; $src--; |
574bacfe |
1208 | } |
61f5c3f5 |
1209 | # set lowest parts to 0 |
1210 | while ($dst >= 0) { $x->[$dst--] = 0; } |
1211 | # fix spurios last zero element |
1212 | splice @$x,-1 if $x->[-1] == 0; |
574bacfe |
1213 | $x; |
1214 | } |
1215 | |
027dc388 |
1216 | sub _pow |
1217 | { |
1218 | # power of $x to $y |
1219 | # ref to array, ref to array, return ref to array |
1220 | my ($c,$cx,$cy) = @_; |
1221 | |
1222 | my $pow2 = _one(); |
1223 | my $two = _two(); |
1224 | my $y1 = _copy($c,$cy); |
1225 | while (!_is_one($c,$y1)) |
1226 | { |
1227 | _mul($c,$pow2,$cx) if _is_odd($c,$y1); |
1228 | _div($c,$y1,$two); |
1229 | _mul($c,$cx,$cx); |
1230 | } |
1231 | _mul($c,$cx,$pow2) unless _is_one($c,$pow2); |
61f5c3f5 |
1232 | $cx; |
027dc388 |
1233 | } |
1234 | |
b3abae2a |
1235 | sub _fac |
1236 | { |
1237 | # factorial of $x |
1238 | # ref to array, return ref to array |
1239 | my ($c,$cx) = @_; |
1240 | |
1241 | if ((@$cx == 1) && ($cx->[0] <= 2)) |
1242 | { |
1243 | $cx->[0] = 1 * ($cx->[0]||1); # 0,1 => 1, 2 => 2 |
1244 | return $cx; |
1245 | } |
1246 | |
1247 | # go forward until $base is exceeded |
1248 | # limit is either $x or $base (x == 100 means as result too high) |
1249 | my $steps = 100; $steps = $cx->[0] if @$cx == 1; |
1250 | my $r = 2; my $cf = 3; my $step = 1; my $last = $r; |
1251 | while ($r < $BASE && $step < $steps) |
1252 | { |
1253 | $last = $r; $r *= $cf++; $step++; |
1254 | } |
1255 | if ((@$cx == 1) && ($step == $cx->[0])) |
1256 | { |
1257 | # completely done |
1258 | $cx = [$last]; |
1259 | return $cx; |
1260 | } |
1261 | my $n = _copy($c,$cx); |
1262 | $cx = [$last]; |
1263 | |
1264 | #$cx = _one(); |
1265 | while (!(@$n == 1 && $n->[0] == $step)) |
1266 | { |
1267 | _mul($c,$cx,$n); _dec($c,$n); |
1268 | } |
1269 | $cx; |
1270 | } |
1271 | |
1272 | use constant DEBUG => 0; |
1273 | |
1274 | my $steps = 0; |
1275 | |
1276 | sub steps { $steps }; |
1277 | |
1278 | sub _sqrt |
0716bf9b |
1279 | { |
394e6ffb |
1280 | # square-root of $x |
1281 | # ref to array, return ref to array |
1282 | my ($c,$x) = @_; |
0716bf9b |
1283 | |
394e6ffb |
1284 | if (scalar @$x == 1) |
1285 | { |
1286 | # fit's into one Perl scalar |
1287 | $x->[0] = int(sqrt($x->[0])); |
1288 | return $x; |
1289 | } |
1290 | my $y = _copy($c,$x); |
b3abae2a |
1291 | # hopefully _len/2 is < $BASE, the -1 is to always undershot the guess |
1292 | # since our guess will "grow" |
1293 | my $l = int((_len($c,$x)-1) / 2); |
1294 | |
1295 | my $lastelem = $x->[-1]; # for guess |
1296 | my $elems = scalar @$x - 1; |
1297 | # not enough digits, but could have more? |
1298 | if ((length($lastelem) <= 3) && ($elems > 1)) |
1299 | { |
1300 | # right-align with zero pad |
1301 | my $len = length($lastelem) & 1; |
1302 | print "$lastelem => " if DEBUG; |
1303 | $lastelem .= substr($x->[-2] . '0' x $BASE_LEN,0,$BASE_LEN); |
1304 | # former odd => make odd again, or former even to even again |
1305 | $lastelem = $lastelem / 10 if (length($lastelem) & 1) != $len; |
1306 | print "$lastelem\n" if DEBUG; |
1307 | } |
0716bf9b |
1308 | |
61f5c3f5 |
1309 | # construct $x (instead of _lsft($c,$x,$l,10) |
1310 | my $r = $l % $BASE_LEN; # 10000 00000 00000 00000 ($BASE_LEN=5) |
1311 | $l = int($l / $BASE_LEN); |
b3abae2a |
1312 | print "l = $l " if DEBUG; |
1313 | |
1314 | splice @$x,$l; # keep ref($x), but modify it |
1315 | |
1316 | # we make the first part of the guess not '1000...0' but int(sqrt($lastelem)) |
1317 | # that gives us: |
1318 | # 14400 00000 => sqrt(14400) => 120 |
1319 | # 144000 000000 => sqrt(144000) => 379 |
1320 | |
1321 | # $x->[$l--] = int('1' . '0' x $r); # old way of guessing |
1322 | print "$lastelem (elems $elems) => " if DEBUG; |
1323 | $lastelem = $lastelem / 10 if ($elems & 1 == 1); # odd or even? |
1324 | my $g = sqrt($lastelem); $g =~ s/\.//; # 2.345 => 2345 |
1325 | $r -= 1 if $elems & 1 == 0; # 70 => 7 |
1326 | |
1327 | # padd with zeros if result is too short |
1328 | $x->[$l--] = int(substr($g . '0' x $r,0,$r+1)); |
1329 | print "now ",$x->[-1] if DEBUG; |
1330 | print " would have been ", int('1' . '0' x $r),"\n" if DEBUG; |
1331 | |
1332 | # If @$x > 1, we could compute the second elem of the guess, too, to create |
1333 | # an even better guess. Not implemented yet. |
1334 | $x->[$l--] = 0 while ($l >= 0); # all other digits of guess are zero |
61f5c3f5 |
1335 | |
b3abae2a |
1336 | print "start x= ",${_str($c,$x)},"\n" if DEBUG; |
394e6ffb |
1337 | my $two = _two(); |
1338 | my $last = _zero(); |
1339 | my $lastlast = _zero(); |
b3abae2a |
1340 | $steps = 0 if DEBUG; |
394e6ffb |
1341 | while (_acmp($c,$last,$x) != 0 && _acmp($c,$lastlast,$x) != 0) |
1342 | { |
b3abae2a |
1343 | $steps++ if DEBUG; |
394e6ffb |
1344 | $lastlast = _copy($c,$last); |
1345 | $last = _copy($c,$x); |
1346 | _add($c,$x, _div($c,_copy($c,$y),$x)); |
1347 | _div($c,$x, $two ); |
b3abae2a |
1348 | print " x= ",${_str($c,$x)},"\n" if DEBUG; |
394e6ffb |
1349 | } |
b3abae2a |
1350 | print "\nsteps in sqrt: $steps, " if DEBUG; |
394e6ffb |
1351 | _dec($c,$x) if _acmp($c,$y,_mul($c,_copy($c,$x),$x)) < 0; # overshot? |
b3abae2a |
1352 | print " final ",$x->[-1],"\n" if DEBUG; |
394e6ffb |
1353 | $x; |
0716bf9b |
1354 | } |
1355 | |
394e6ffb |
1356 | ############################################################################## |
1357 | # binary stuff |
0716bf9b |
1358 | |
394e6ffb |
1359 | sub _and |
1360 | { |
1361 | my ($c,$x,$y) = @_; |
0716bf9b |
1362 | |
394e6ffb |
1363 | # the shortcut makes equal, large numbers _really_ fast, and makes only a |
1364 | # very small performance drop for small numbers (e.g. something with less |
1365 | # than 32 bit) Since we optimize for large numbers, this is enabled. |
1366 | return $x if _acmp($c,$x,$y) == 0; # shortcut |
0716bf9b |
1367 | |
394e6ffb |
1368 | my $m = _one(); my ($xr,$yr); |
1369 | my $mask = $AND_MASK; |
1370 | |
1371 | my $x1 = $x; |
1372 | my $y1 = _copy($c,$y); # make copy |
1373 | $x = _zero(); |
1374 | my ($b,$xrr,$yrr); |
1375 | use integer; |
1376 | while (!_is_zero($c,$x1) && !_is_zero($c,$y1)) |
1377 | { |
1378 | ($x1, $xr) = _div($c,$x1,$mask); |
1379 | ($y1, $yr) = _div($c,$y1,$mask); |
1380 | |
1381 | # make ints() from $xr, $yr |
1382 | # this is when the AND_BITS are greater tahn $BASE and is slower for |
1383 | # small (<256 bits) numbers, but faster for large numbers. Disabled |
1384 | # due to KISS principle |
1385 | |
1386 | # $b = 1; $xrr = 0; foreach (@$xr) { $xrr += $_ * $b; $b *= $BASE; } |
1387 | # $b = 1; $yrr = 0; foreach (@$yr) { $yrr += $_ * $b; $b *= $BASE; } |
1388 | # _add($c,$x, _mul($c, _new( $c, \($xrr & $yrr) ), $m) ); |
1389 | |
61f5c3f5 |
1390 | # 0+ due to '&' doesn't work in strings |
1391 | _add($c,$x, _mul($c, [ 0+$xr->[0] & 0+$yr->[0] ], $m) ); |
394e6ffb |
1392 | _mul($c,$m,$mask); |
1393 | } |
1394 | $x; |
0716bf9b |
1395 | } |
1396 | |
394e6ffb |
1397 | sub _xor |
0716bf9b |
1398 | { |
394e6ffb |
1399 | my ($c,$x,$y) = @_; |
1400 | |
1401 | return _zero() if _acmp($c,$x,$y) == 0; # shortcut (see -and) |
1402 | |
1403 | my $m = _one(); my ($xr,$yr); |
1404 | my $mask = $XOR_MASK; |
1405 | |
1406 | my $x1 = $x; |
1407 | my $y1 = _copy($c,$y); # make copy |
1408 | $x = _zero(); |
1409 | my ($b,$xrr,$yrr); |
1410 | use integer; |
1411 | while (!_is_zero($c,$x1) && !_is_zero($c,$y1)) |
0716bf9b |
1412 | { |
394e6ffb |
1413 | ($x1, $xr) = _div($c,$x1,$mask); |
1414 | ($y1, $yr) = _div($c,$y1,$mask); |
1415 | # make ints() from $xr, $yr (see _and()) |
1416 | #$b = 1; $xrr = 0; foreach (@$xr) { $xrr += $_ * $b; $b *= $BASE; } |
1417 | #$b = 1; $yrr = 0; foreach (@$yr) { $yrr += $_ * $b; $b *= $BASE; } |
1418 | #_add($c,$x, _mul($c, _new( $c, \($xrr ^ $yrr) ), $m) ); |
61f5c3f5 |
1419 | |
1420 | # 0+ due to '^' doesn't work in strings |
1421 | _add($c,$x, _mul($c, [ 0+$xr->[0] ^ 0+$yr->[0] ], $m) ); |
394e6ffb |
1422 | _mul($c,$m,$mask); |
0716bf9b |
1423 | } |
394e6ffb |
1424 | # the loop stops when the shorter of the two numbers is exhausted |
1425 | # the remainder of the longer one will survive bit-by-bit, so we simple |
1426 | # multiply-add it in |
1427 | _add($c,$x, _mul($c, $x1, $m) ) if !_is_zero($c,$x1); |
1428 | _add($c,$x, _mul($c, $y1, $m) ) if !_is_zero($c,$y1); |
1429 | |
1430 | $x; |
0716bf9b |
1431 | } |
1432 | |
394e6ffb |
1433 | sub _or |
0716bf9b |
1434 | { |
394e6ffb |
1435 | my ($c,$x,$y) = @_; |
0716bf9b |
1436 | |
394e6ffb |
1437 | return $x if _acmp($c,$x,$y) == 0; # shortcut (see _and) |
0716bf9b |
1438 | |
394e6ffb |
1439 | my $m = _one(); my ($xr,$yr); |
1440 | my $mask = $OR_MASK; |
0716bf9b |
1441 | |
394e6ffb |
1442 | my $x1 = $x; |
1443 | my $y1 = _copy($c,$y); # make copy |
1444 | $x = _zero(); |
1445 | my ($b,$xrr,$yrr); |
1446 | use integer; |
1447 | while (!_is_zero($c,$x1) && !_is_zero($c,$y1)) |
1448 | { |
1449 | ($x1, $xr) = _div($c,$x1,$mask); |
1450 | ($y1, $yr) = _div($c,$y1,$mask); |
1451 | # make ints() from $xr, $yr (see _and()) |
1452 | # $b = 1; $xrr = 0; foreach (@$xr) { $xrr += $_ * $b; $b *= $BASE; } |
1453 | # $b = 1; $yrr = 0; foreach (@$yr) { $yrr += $_ * $b; $b *= $BASE; } |
1454 | # _add($c,$x, _mul($c, _new( $c, \($xrr | $yrr) ), $m) ); |
1455 | |
61f5c3f5 |
1456 | # 0+ due to '|' doesn't work in strings |
1457 | _add($c,$x, _mul($c, [ 0+$xr->[0] | 0+$yr->[0] ], $m) ); |
394e6ffb |
1458 | _mul($c,$m,$mask); |
1459 | } |
1460 | # the loop stops when the shorter of the two numbers is exhausted |
1461 | # the remainder of the longer one will survive bit-by-bit, so we simple |
1462 | # multiply-add it in |
1463 | _add($c,$x, _mul($c, $x1, $m) ) if !_is_zero($c,$x1); |
1464 | _add($c,$x, _mul($c, $y1, $m) ) if !_is_zero($c,$y1); |
1465 | |
1466 | $x; |
0716bf9b |
1467 | } |
1468 | |
61f5c3f5 |
1469 | sub _as_hex |
1470 | { |
1471 | # convert a decimal number to hex (ref to array, return ref to string) |
1472 | my ($c,$x) = @_; |
1473 | |
1474 | my $x1 = _copy($c,$x); |
1475 | |
1476 | my $es = ''; |
1477 | my $xr; |
1478 | my $x10000 = [ 0x10000 ]; |
1479 | while (! _is_zero($c,$x1)) |
1480 | { |
1481 | ($x1, $xr) = _div($c,$x1,$x10000); |
1482 | $es .= unpack('h4',pack('v',$xr->[0])); |
1483 | } |
1484 | $es = reverse $es; |
1485 | $es =~ s/^[0]+//; # strip leading zeros |
1486 | $es = '0x' . $es; |
1487 | \$es; |
1488 | } |
1489 | |
1490 | sub _as_bin |
1491 | { |
1492 | # convert a decimal number to bin (ref to array, return ref to string) |
1493 | my ($c,$x) = @_; |
1494 | |
1495 | my $x1 = _copy($c,$x); |
1496 | |
1497 | my $es = ''; |
1498 | my $xr; |
1499 | my $x10000 = [ 0x10000 ]; |
1500 | while (! _is_zero($c,$x1)) |
1501 | { |
1502 | ($x1, $xr) = _div($c,$x1,$x10000); |
1503 | $es .= unpack('b16',pack('v',$xr->[0])); |
1504 | } |
1505 | $es = reverse $es; |
1506 | $es =~ s/^[0]+//; # strip leading zeros |
1507 | $es = '0b' . $es; |
1508 | \$es; |
1509 | } |
1510 | |
394e6ffb |
1511 | sub _from_hex |
0716bf9b |
1512 | { |
394e6ffb |
1513 | # convert a hex number to decimal (ref to string, return ref to array) |
1514 | my ($c,$hs) = @_; |
0716bf9b |
1515 | |
394e6ffb |
1516 | my $mul = _one(); |
1517 | my $m = [ 0x10000 ]; # 16 bit at a time |
1518 | my $x = _zero(); |
0716bf9b |
1519 | |
61f5c3f5 |
1520 | my $len = length($$hs)-2; |
394e6ffb |
1521 | $len = int($len/4); # 4-digit parts, w/o '0x' |
1522 | my $val; my $i = -4; |
1523 | while ($len >= 0) |
1524 | { |
1525 | $val = substr($$hs,$i,4); |
1526 | $val =~ s/^[+-]?0x// if $len == 0; # for last part only because |
1527 | $val = hex($val); # hex does not like wrong chars |
1528 | $i -= 4; $len --; |
1529 | _add ($c, $x, _mul ($c, [ $val ], $mul ) ) if $val != 0; |
1530 | _mul ($c, $mul, $m ) if $len >= 0; # skip last mul |
1531 | } |
1532 | $x; |
1533 | } |
1534 | |
1535 | sub _from_bin |
0716bf9b |
1536 | { |
394e6ffb |
1537 | # convert a hex number to decimal (ref to string, return ref to array) |
1538 | my ($c,$bs) = @_; |
0716bf9b |
1539 | |
13a12e00 |
1540 | # instead of converting 8 bit at a time, it is faster to convert the |
1541 | # number to hex, and then call _from_hex. |
1542 | |
1543 | my $hs = $$bs; |
1544 | $hs =~ s/^[+-]?0b//; # remove sign and 0b |
1545 | my $l = length($hs); # bits |
1546 | $hs = '0' x (8-($l % 8)) . $hs if ($l % 8) != 0; # padd left side w/ 0 |
1547 | my $h = unpack('H*', pack ('B*', $hs)); # repack as hex |
1548 | return $c->_from_hex(\('0x'.$h)); |
1549 | |
394e6ffb |
1550 | my $mul = _one(); |
1551 | my $m = [ 0x100 ]; # 8 bit at a time |
1552 | my $x = _zero(); |
0716bf9b |
1553 | |
61f5c3f5 |
1554 | my $len = length($$bs)-2; |
394e6ffb |
1555 | $len = int($len/8); # 4-digit parts, w/o '0x' |
1556 | my $val; my $i = -8; |
1557 | while ($len >= 0) |
0716bf9b |
1558 | { |
394e6ffb |
1559 | $val = substr($$bs,$i,8); |
1560 | $val =~ s/^[+-]?0b// if $len == 0; # for last part only |
1561 | |
394e6ffb |
1562 | $val = ord(pack('B8',substr('00000000'.$val,-8,8))); |
1563 | |
1564 | $i -= 8; $len --; |
1565 | _add ($c, $x, _mul ($c, [ $val ], $mul ) ) if $val != 0; |
1566 | _mul ($c, $mul, $m ) if $len >= 0; # skip last mul |
0716bf9b |
1567 | } |
394e6ffb |
1568 | $x; |
0716bf9b |
1569 | } |
1570 | |
394e6ffb |
1571 | ############################################################################## |
1572 | ############################################################################## |
1573 | |
0716bf9b |
1574 | 1; |
1575 | __END__ |
1576 | |
1577 | =head1 NAME |
1578 | |
1579 | Math::BigInt::Calc - Pure Perl module to support Math::BigInt |
1580 | |
1581 | =head1 SYNOPSIS |
1582 | |
ee15d750 |
1583 | Provides support for big integer calculations. Not intended to be used by other |
1584 | modules (except Math::BigInt::Cached). Other modules which sport the same |
1585 | functions can also be used to support Math::Bigint, like Math::BigInt::Pari. |
0716bf9b |
1586 | |
1587 | =head1 DESCRIPTION |
1588 | |
027dc388 |
1589 | In order to allow for multiple big integer libraries, Math::BigInt was |
1590 | rewritten to use library modules for core math routines. Any module which |
1591 | follows the same API as this can be used instead by using the following: |
0716bf9b |
1592 | |
ee15d750 |
1593 | use Math::BigInt lib => 'libname'; |
0716bf9b |
1594 | |
027dc388 |
1595 | 'libname' is either the long name ('Math::BigInt::Pari'), or only the short |
1596 | version like 'Pari'. |
1597 | |
0716bf9b |
1598 | =head1 EXPORT |
1599 | |
027dc388 |
1600 | The following functions MUST be defined in order to support the use by |
1601 | Math::BigInt: |
0716bf9b |
1602 | |
1603 | _new(string) return ref to new object from ref to decimal string |
1604 | _zero() return a new object with value 0 |
1605 | _one() return a new object with value 1 |
1606 | |
1607 | _str(obj) return ref to a string representing the object |
1608 | _num(obj) returns a Perl integer/floating point number |
1609 | NOTE: because of Perl numeric notation defaults, |
1610 | the _num'ified obj may lose accuracy due to |
1611 | machine-dependend floating point size limitations |
1612 | |
1613 | _add(obj,obj) Simple addition of two objects |
1614 | _mul(obj,obj) Multiplication of two objects |
1615 | _div(obj,obj) Division of the 1st object by the 2nd |
b22b3e31 |
1616 | In list context, returns (result,remainder). |
1617 | NOTE: this is integer math, so no |
1618 | fractional part will be returned. |
1619 | _sub(obj,obj) Simple subtraction of 1 object from another |
0716bf9b |
1620 | a third, optional parameter indicates that the params |
1621 | are swapped. In this case, the first param needs to |
1622 | be preserved, while you can destroy the second. |
1623 | sub (x,y,1) => return x - y and keep x intact! |
e745a66c |
1624 | _dec(obj) decrement object by one (input is garant. to be > 0) |
1625 | _inc(obj) increment object by one |
1626 | |
0716bf9b |
1627 | |
1628 | _acmp(obj,obj) <=> operator for objects (return -1, 0 or 1) |
1629 | |
1630 | _len(obj) returns count of the decimal digits of the object |
1631 | _digit(obj,n) returns the n'th decimal digit of object |
1632 | |
1633 | _is_one(obj) return true if argument is +1 |
1634 | _is_zero(obj) return true if argument is 0 |
1635 | _is_even(obj) return true if argument is even (0,2,4,6..) |
1636 | _is_odd(obj) return true if argument is odd (1,3,5,7..) |
1637 | |
1638 | _copy return a ref to a true copy of the object |
1639 | |
1640 | _check(obj) check whether internal representation is still intact |
1641 | return 0 for ok, otherwise error message as string |
1642 | |
bd05a461 |
1643 | The following functions are optional, and can be defined if the underlying lib |
027dc388 |
1644 | has a fast way to do them. If undefined, Math::BigInt will use pure Perl (hence |
1645 | slow) fallback routines to emulate these: |
0716bf9b |
1646 | |
1647 | _from_hex(str) return ref to new object from ref to hexadecimal string |
1648 | _from_bin(str) return ref to new object from ref to binary string |
1649 | |
ee15d750 |
1650 | _as_hex(str) return ref to scalar string containing the value as |
1651 | unsigned hex string, with the '0x' prepended. |
1652 | Leading zeros must be stripped. |
1653 | _as_bin(str) Like as_hex, only as binary string containing only |
1654 | zeros and ones. Leading zeros must be stripped and a |
1655 | '0b' must be prepended. |
1656 | |
0716bf9b |
1657 | _rsft(obj,N,B) shift object in base B by N 'digits' right |
dccbb853 |
1658 | For unsupported bases B, return undef to signal failure |
0716bf9b |
1659 | _lsft(obj,N,B) shift object in base B by N 'digits' left |
dccbb853 |
1660 | For unsupported bases B, return undef to signal failure |
0716bf9b |
1661 | |
1662 | _xor(obj1,obj2) XOR (bit-wise) object 1 with object 2 |
dccbb853 |
1663 | Note: XOR, AND and OR pad with zeros if size mismatches |
0716bf9b |
1664 | _and(obj1,obj2) AND (bit-wise) object 1 with object 2 |
1665 | _or(obj1,obj2) OR (bit-wise) object 1 with object 2 |
1666 | |
dccbb853 |
1667 | _mod(obj,obj) Return remainder of div of the 1st by the 2nd object |
394e6ffb |
1668 | _sqrt(obj) return the square root of object (truncate to int) |
b3abae2a |
1669 | _fac(obj) return factorial of object 1 (1*2*3*4..) |
0716bf9b |
1670 | _pow(obj,obj) return object 1 to the power of object 2 |
1671 | _gcd(obj,obj) return Greatest Common Divisor of two objects |
1672 | |
b22b3e31 |
1673 | _zeros(obj) return number of trailing decimal zeros |
0716bf9b |
1674 | |
b22b3e31 |
1675 | Input strings come in as unsigned but with prefix (i.e. as '123', '0xabc' |
0716bf9b |
1676 | or '0b1101'). |
1677 | |
b22b3e31 |
1678 | Testing of input parameter validity is done by the caller, so you need not |
574bacfe |
1679 | worry about underflow (f.i. in C<_sub()>, C<_dec()>) nor about division by |
1680 | zero or similar cases. |
1681 | |
1682 | The first parameter can be modified, that includes the possibility that you |
1683 | return a reference to a completely different object instead. Although keeping |
dccbb853 |
1684 | the reference and just changing it's contents is prefered over creating and |
1685 | returning a different reference. |
574bacfe |
1686 | |
1687 | Return values are always references to objects or strings. Exceptions are |
1688 | C<_lsft()> and C<_rsft()>, which return undef if they can not shift the |
027dc388 |
1689 | argument. This is used to delegate shifting of bases different than the one |
1690 | you can support back to Math::BigInt, which will use some generic code to |
1691 | calculate the result. |
574bacfe |
1692 | |
1693 | =head1 WRAP YOUR OWN |
1694 | |
1695 | If you want to port your own favourite c-lib for big numbers to the |
1696 | Math::BigInt interface, you can take any of the already existing modules as |
1697 | a rough guideline. You should really wrap up the latest BigInt and BigFloat |
bd05a461 |
1698 | testsuites with your module, and replace in them any of the following: |
574bacfe |
1699 | |
1700 | use Math::BigInt; |
1701 | |
bd05a461 |
1702 | by this: |
574bacfe |
1703 | |
1704 | use Math::BigInt lib => 'yourlib'; |
1705 | |
1706 | This way you ensure that your library really works 100% within Math::BigInt. |
0716bf9b |
1707 | |
1708 | =head1 LICENSE |
1709 | |
1710 | This program is free software; you may redistribute it and/or modify it under |
1711 | the same terms as Perl itself. |
1712 | |
1713 | =head1 AUTHORS |
1714 | |
1715 | Original math code by Mark Biggar, rewritten by Tels L<http://bloodgate.com/> |
1716 | in late 2000, 2001. |
1717 | Seperated from BigInt and shaped API with the help of John Peacock. |
1718 | |
1719 | =head1 SEE ALSO |
1720 | |
ee15d750 |
1721 | L<Math::BigInt>, L<Math::BigFloat>, L<Math::BigInt::BitVect>, |
1722 | L<Math::BigInt::GMP>, L<Math::BigInt::Cached> and L<Math::BigInt::Pari>. |
0716bf9b |
1723 | |
1724 | =cut |