This is my patch patch.0a for perl5.000.
[p5sagit/p5-mst-13.2.git] / lib / Math / BigInt.pm
CommitLineData
a0d0e21e 1package Math::BigInt;
2
3%OVERLOAD = (
4 # Anonymous subroutines:
5'+' => sub {new BigInt &badd},
6'-' => sub {new BigInt
7 $_[2]? bsub($_[1],${$_[0]}) : bsub(${$_[0]},$_[1])},
8'<=>' => sub {new BigInt
9 $_[2]? bcmp($_[1],${$_[0]}) : bcmp(${$_[0]},$_[1])},
10'cmp' => sub {new BigInt
11 $_[2]? ($_[1] cmp ${$_[0]}) : (${$_[0]} cmp $_[1])},
12'*' => sub {new BigInt &bmul},
13'/' => sub {new BigInt
14 $_[2]? scalar bdiv($_[1],${$_[0]}) :
15 scalar bdiv(${$_[0]},$_[1])},
16'%' => sub {new BigInt
17 $_[2]? bmod($_[1],${$_[0]}) : bmod(${$_[0]},$_[1])},
18'**' => sub {new BigInt
19 $_[2]? bpow($_[1],${$_[0]}) : bpow(${$_[0]},$_[1])},
20'neg' => sub {new BigInt &bneg},
21'abs' => sub {new BigInt &babs},
22
23qw(
24"" stringify
250+ numify) # Order of arguments unsignificant
26);
27
28sub new {
29 my $foo = bnorm($_[1]);
30 die "Not a number initialized to BigInt" if $foo eq "NaN";
31 bless \$foo;
32}
33sub stringify { "${$_[0]}" }
34sub numify { 0 + "${$_[0]}" } # Not needed, additional overhead
35 # comparing to direct compilation based on
36 # stringify
37
38# arbitrary size integer math package
39#
40# by Mark Biggar
41#
42# Canonical Big integer value are strings of the form
43# /^[+-]\d+$/ with leading zeros suppressed
44# Input values to these routines may be strings of the form
45# /^\s*[+-]?[\d\s]+$/.
46# Examples:
47# '+0' canonical zero value
48# ' -123 123 123' canonical value '-123123123'
49# '1 23 456 7890' canonical value '+1234567890'
50# Output values always always in canonical form
51#
52# Actual math is done in an internal format consisting of an array
53# whose first element is the sign (/^[+-]$/) and whose remaining
54# elements are base 100000 digits with the least significant digit first.
55# The string 'NaN' is used to represent the result when input arguments
56# are not numbers, as well as the result of dividing by zero
57#
58# routines provided are:
59#
60# bneg(BINT) return BINT negation
61# babs(BINT) return BINT absolute value
62# bcmp(BINT,BINT) return CODE compare numbers (undef,<0,=0,>0)
63# badd(BINT,BINT) return BINT addition
64# bsub(BINT,BINT) return BINT subtraction
65# bmul(BINT,BINT) return BINT multiplication
66# bdiv(BINT,BINT) return (BINT,BINT) division (quo,rem) just quo if scalar
67# bmod(BINT,BINT) return BINT modulus
68# bgcd(BINT,BINT) return BINT greatest common divisor
69# bnorm(BINT) return BINT normalization
70#
71
72$zero = 0;
73
74\f
75# normalize string form of number. Strip leading zeros. Strip any
76# white space and add a sign, if missing.
77# Strings that are not numbers result the value 'NaN'.
78
79sub bnorm { #(num_str) return num_str
80 local($_) = @_;
81 s/\s+//g; # strip white space
82 if (s/^([+-]?)0*(\d+)$/$1$2/) { # test if number
83 substr($_,$[,0) = '+' unless $1; # Add missing sign
84 s/^-0/+0/;
85 $_;
86 } else {
87 'NaN';
88 }
89}
90
91# Convert a number from string format to internal base 100000 format.
92# Assumes normalized value as input.
93sub internal { #(num_str) return int_num_array
94 local($d) = @_;
95 ($is,$il) = (substr($d,$[,1),length($d)-2);
96 substr($d,$[,1) = '';
97 ($is, reverse(unpack("a" . ($il%5+1) . ("a5" x ($il/5)), $d)));
98}
99
100# Convert a number from internal base 100000 format to string format.
101# This routine scribbles all over input array.
102sub external { #(int_num_array) return num_str
103 $es = shift;
104 grep($_ > 9999 || ($_ = substr('0000'.$_,-5)), @_); # zero pad
105 &bnorm(join('', $es, reverse(@_))); # reverse concat and normalize
106}
107
108# Negate input value.
109sub bneg { #(num_str) return num_str
110 local($_) = &bnorm(@_);
111 vec($_,0,8) ^= ord('+') ^ ord('-') unless $_ eq '+0';
112 s/^H/N/;
113 $_;
114}
115
116# Returns the absolute value of the input.
117sub babs { #(num_str) return num_str
118 &abs(&bnorm(@_));
119}
120
121sub abs { # post-normalized abs for internal use
122 local($_) = @_;
123 s/^-/+/;
124 $_;
125}
126\f
127# Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
128sub bcmp { #(num_str, num_str) return cond_code
129 local($x,$y) = (&bnorm($_[$[]),&bnorm($_[$[+1]));
130 if ($x eq 'NaN') {
131 undef;
132 } elsif ($y eq 'NaN') {
133 undef;
134 } else {
135 &cmp($x,$y);
136 }
137}
138
139sub cmp { # post-normalized compare for internal use
140 local($cx, $cy) = @_;
141 $cx cmp $cy
142 &&
143 (
144 ord($cy) <=> ord($cx)
145 ||
146 ($cx cmp ',') * (length($cy) <=> length($cx) || $cy cmp $cx)
147 );
148}
149
150sub badd { #(num_str, num_str) return num_str
151 local(*x, *y); ($x, $y) = (&bnorm($_[$[]),&bnorm($_[$[+1]));
152 if ($x eq 'NaN') {
153 'NaN';
154 } elsif ($y eq 'NaN') {
155 'NaN';
156 } else {
157 @x = &internal($x); # convert to internal form
158 @y = &internal($y);
159 local($sx, $sy) = (shift @x, shift @y); # get signs
160 if ($sx eq $sy) {
161 &external($sx, &add(*x, *y)); # if same sign add
162 } else {
163 ($x, $y) = (&abs($x),&abs($y)); # make abs
164 if (&cmp($y,$x) > 0) {
165 &external($sy, &sub(*y, *x));
166 } else {
167 &external($sx, &sub(*x, *y));
168 }
169 }
170 }
171}
172
173sub bsub { #(num_str, num_str) return num_str
174 &badd($_[$[],&bneg($_[$[+1]));
175}
176
177# GCD -- Euclids algorithm Knuth Vol 2 pg 296
178sub bgcd { #(num_str, num_str) return num_str
179 local($x,$y) = (&bnorm($_[$[]),&bnorm($_[$[+1]));
180 if ($x eq 'NaN' || $y eq 'NaN') {
181 'NaN';
182 } else {
183 ($x, $y) = ($y,&bmod($x,$y)) while $y ne '+0';
184 $x;
185 }
186}
187\f
188# routine to add two base 1e5 numbers
189# stolen from Knuth Vol 2 Algorithm A pg 231
190# there are separate routines to add and sub as per Kunth pg 233
191sub add { #(int_num_array, int_num_array) return int_num_array
192 local(*x, *y) = @_;
193 $car = 0;
194 for $x (@x) {
195 last unless @y || $car;
196 $x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5);
197 }
198 for $y (@y) {
199 last unless $car;
200 $y -= 1e5 if $car = (($y += $car) >= 1e5);
201 }
202 (@x, @y, $car);
203}
204
205# subtract base 1e5 numbers -- stolen from Knuth Vol 2 pg 232, $x > $y
206sub sub { #(int_num_array, int_num_array) return int_num_array
207 local(*sx, *sy) = @_;
208 $bar = 0;
209 for $sx (@sx) {
210 last unless @y || $bar;
211 $sx += 1e5 if $bar = (($sx -= shift(@sy) + $bar) < 0);
212 }
213 @sx;
214}
215
216# multiply two numbers -- stolen from Knuth Vol 2 pg 233
217sub bmul { #(num_str, num_str) return num_str
218 local(*x, *y); ($x, $y) = (&bnorm($_[$[]), &bnorm($_[$[+1]));
219 if ($x eq 'NaN') {
220 'NaN';
221 } elsif ($y eq 'NaN') {
222 'NaN';
223 } else {
224 @x = &internal($x);
225 @y = &internal($y);
226 &external(&mul(*x,*y));
227 }
228}
229
230# multiply two numbers in internal representation
231# destroys the arguments, supposes that two arguments are different
232sub mul { #(*int_num_array, *int_num_array) return int_num_array
233 local(*x, *y) = (shift, shift);
234 local($signr) = (shift @x ne shift @y) ? '-' : '+';
235 @prod = ();
236 for $x (@x) {
237 ($car, $cty) = (0, $[);
238 for $y (@y) {
239 $prod = $x * $y + $prod[$cty] + $car;
240 $prod[$cty++] =
241 $prod - ($car = int($prod * 1e-5)) * 1e5;
242 }
243 $prod[$cty] += $car if $car;
244 $x = shift @prod;
245 }
246 ($signr, @x, @prod);
247}
248
249# modulus
250sub bmod { #(num_str, num_str) return num_str
251 (&bdiv(@_))[$[+1];
252}
253\f
254sub bdiv { #(dividend: num_str, divisor: num_str) return num_str
255 local (*x, *y); ($x, $y) = (&bnorm($_[$[]), &bnorm($_[$[+1]));
256 return wantarray ? ('NaN','NaN') : 'NaN'
257 if ($x eq 'NaN' || $y eq 'NaN' || $y eq '+0');
258 return wantarray ? ('+0',$x) : '+0' if (&cmp(&abs($x),&abs($y)) < 0);
259 @x = &internal($x); @y = &internal($y);
260 $srem = $y[$[];
261 $sr = (shift @x ne shift @y) ? '-' : '+';
262 $car = $bar = $prd = 0;
263 if (($dd = int(1e5/($y[$#y]+1))) != 1) {
264 for $x (@x) {
265 $x = $x * $dd + $car;
266 $x -= ($car = int($x * 1e-5)) * 1e5;
267 }
268 push(@x, $car); $car = 0;
269 for $y (@y) {
270 $y = $y * $dd + $car;
271 $y -= ($car = int($y * 1e-5)) * 1e5;
272 }
273 }
274 else {
275 push(@x, 0);
276 }
277 @q = (); ($v2,$v1) = @y[-2,-1];
278 while ($#x > $#y) {
279 ($u2,$u1,$u0) = @x[-3..-1];
280 $q = (($u0 == $v1) ? 99999 : int(($u0*1e5+$u1)/$v1));
281 --$q while ($v2*$q > ($u0*1e5+$u1-$q*$v1)*1e5+$u2);
282 if ($q) {
283 ($car, $bar) = (0,0);
284 for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
285 $prd = $q * $y[$y] + $car;
286 $prd -= ($car = int($prd * 1e-5)) * 1e5;
287 $x[$x] += 1e5 if ($bar = (($x[$x] -= $prd + $bar) < 0));
288 }
289 if ($x[$#x] < $car + $bar) {
290 $car = 0; --$q;
291 for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
292 $x[$x] -= 1e5
293 if ($car = (($x[$x] += $y[$y] + $car) > 1e5));
294 }
295 }
296 }
297 pop(@x); unshift(@q, $q);
298 }
299 if (wantarray) {
300 @d = ();
301 if ($dd != 1) {
302 $car = 0;
303 for $x (reverse @x) {
304 $prd = $car * 1e5 + $x;
305 $car = $prd - ($tmp = int($prd / $dd)) * $dd;
306 unshift(@d, $tmp);
307 }
308 }
309 else {
310 @d = @x;
311 }
312 (&external($sr, @q), &external($srem, @d, $zero));
313 } else {
314 &external($sr, @q);
315 }
316}
317
318# compute power of two numbers -- stolen from Knuth Vol 2 pg 233
319sub bpow { #(num_str, num_str) return num_str
320 local(*x, *y); ($x, $y) = (&bnorm($_[$[]), &bnorm($_[$[+1]));
321 if ($x eq 'NaN') {
322 'NaN';
323 } elsif ($y eq 'NaN') {
324 'NaN';
325 } elsif ($x eq '+1') {
326 '+1';
327 } elsif ($x eq '-1') {
328 &bmod($x,2) ? '-1': '+1';
329 } elsif ($y =~ /^-/) {
330 'NaN';
331 } elsif ($x eq '+0' && $y eq '+0') {
332 'NaN';
333 } else {
334 @x = &internal($x);
335 local(@pow2)=@x;
336 local(@pow)=&internal("+1");
337 local($y1,$res,@tmp1,@tmp2)=(1); # need tmp to send to mul
338 while ($y ne '+0') {
339 ($y,$res)=&bdiv($y,2);
340 if ($res ne '+0') {@tmp=@pow2; @pow=&mul(*pow,*tmp);}
341 if ($y ne '+0') {@tmp=@pow2;@pow2=&mul(*pow2,*tmp);}
342 }
343 &external(@pow);
344 }
345}
346
3471;