3 # arbitrary size integer math package
7 # Canonical Big integer value are strings of the form
8 # /^[+-]\d+$/ with leading zeros suppressed
9 # Input values to these routines may be strings of the form
10 # /^\s*[+-]?[\d\s]+$/.
12 # '+0' canonical zero value
13 # ' -123 123 123' canonical value '-123123123'
14 # '1 23 456 7890' canonical value '+1234567890'
15 # Output values always always in canonical form
17 # Actual math is done in an internal format consisting of an array
18 # whose first element is the sign (/^[+-]$/) and whose remaining
19 # elements are base 100000 digits with the least significant digit first.
20 # The string 'NaN' is used to represent the result when input arguments
21 # are not numbers, as well as the result of dividing by zero
23 # routines provided are:
25 # bneg(BINT) return BINT negation
26 # babs(BINT) return BINT absolute value
27 # bcmp(BINT,BINT) return CODE compare numbers (undef,<0,=0,>0)
28 # badd(BINT,BINT) return BINT addition
29 # bsub(BINT,BINT) return BINT subtraction
30 # bmul(BINT,BINT) return BINT multiplication
31 # bdiv(BINT,BINT) return (BINT,BINT) division (quo,rem) just quo if scalar
32 # bmod(BINT,BINT) return BINT modulus
33 # bgcd(BINT,BINT) return BINT greatest common divisor
34 # bnorm(BINT) return BINT normalization
37 # normalize string form of number. Strip leading zeros. Strip any
38 # white space and add a sign, if missing.
39 # Strings that are not numbers result the value 'NaN'.
40 sub main'bnorm { #(num_str) return num_str
42 s/\s+//g; # strip white space
43 if (s/^([+-]?)0*(\d+)$/$1$2/) { # test if number
44 substr($_,$[,0) = '+' unless $1; # Add missing sign
52 # Convert a number from string format to internal base 100000 format.
53 # Assumes normalized value as input.
54 sub internal { #(num_str) return int_num_array
56 ($is,$il) = (substr($d,$[,1),length($d)-2);
58 ($is, reverse(unpack("a" . ($il%5+1) . ("a5" x ($il/5)), $d)));
61 # Convert a number from internal base 100000 format to string format.
62 # This routine scribbles all over input array.
63 sub external { #(int_num_array) return num_str
65 grep($_ > 9999 || ($_ = substr('0000'.$_,-5)), @_); # zero pad
66 &'bnorm(join('', $es, reverse(@_))); # reverse concat and normalize
70 sub main'bneg { #(num_str) return num_str
71 local($_) = &'bnorm(@_);
72 vec($_,0,8) ^= ord('+') ^ ord('-') unless $_ eq '+0';
77 # Returns the absolute value of the input.
78 sub main'babs { #(num_str) return num_str
82 sub abs { # post-normalized abs for internal use
88 # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
89 sub main'bcmp { #(num_str, num_str) return cond_code
90 local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
93 } elsif ($y eq 'NaN') {
100 sub cmp { # post-normalized compare for internal use
101 local($cx, $cy) = @_;
105 ord($cy) <=> ord($cx)
107 ($cx cmp ',') * (length($cy) <=> length($cx) || $cy cmp $cx)
111 sub main'badd { #(num_str, num_str) return num_str
112 local(*x, *y); ($x, $y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
115 } elsif ($y eq 'NaN') {
118 @x = &internal($x); # convert to internal form
120 local($sx, $sy) = (shift @x, shift @y); # get signs
122 &external($sx, &add(*x, *y)); # if same sign add
124 ($x, $y) = (&abs($x),&abs($y)); # make abs
125 if (&cmp($y,$x) > 0) {
126 &external($sy, &sub(*y, *x));
128 &external($sx, &sub(*x, *y));
134 sub main'bsub { #(num_str, num_str) return num_str
135 &'badd($_[$[],&'bneg($_[$[+1]));
138 # GCD -- Euclids algorithm Knuth Vol 2 pg 296
139 sub main'bgcd { #(num_str, num_str) return num_str
140 local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
141 if ($x eq 'NaN' || $y eq 'NaN') {
144 ($x, $y) = ($y,&'bmod($x,$y)) while $y ne '+0';
149 # routine to add two base 1e5 numbers
150 # stolen from Knuth Vol 2 Algorithm A pg 231
151 # there are separate routines to add and sub as per Kunth pg 233
152 sub add { #(int_num_array, int_num_array) return int_num_array
156 last unless @y || $car;
157 $x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5);
161 $y -= 1e5 if $car = (($y += $car) >= 1e5);
166 # subtract base 1e5 numbers -- stolen from Knuth Vol 2 pg 232, $x > $y
167 sub sub { #(int_num_array, int_num_array) return int_num_array
168 local(*sx, *sy) = @_;
171 last unless @y || $bar;
172 $sx += 1e5 if $bar = (($sx -= shift(@sy) + $bar) < 0);
177 # multiply two numbers -- stolen from Knuth Vol 2 pg 233
178 sub main'bmul { #(num_str, num_str) return num_str
179 local(*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
182 } elsif ($y eq 'NaN') {
187 local($signr) = (shift @x ne shift @y) ? '-' : '+';
190 ($car, $cty) = (0, $[);
192 $prod = $x * $y + $prod[$cty] + $car;
194 $prod - ($car = int($prod * 1e-5)) * 1e5;
196 $prod[$cty] += $car if $car;
199 &external($signr, @x, @prod);
204 sub main'bmod { #(num_str, num_str) return num_str
208 sub main'bdiv { #(dividend: num_str, divisor: num_str) return num_str
209 local (*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
210 return wantarray ? ('NaN','NaN') : 'NaN'
211 if ($x eq 'NaN' || $y eq 'NaN' || $y eq '+0');
212 return wantarray ? ('+0',$x) : '+0' if (&cmp(&abs($x),&abs($y)) < 0);
213 @x = &internal($x); @y = &internal($y);
215 $sr = (shift @x ne shift @y) ? '-' : '+';
216 $car = $bar = $prd = 0;
217 if (($dd = int(1e5/($y[$#y]+1))) != 1) {
219 $x = $x * $dd + $car;
220 $x -= ($car = int($x * 1e-5)) * 1e5;
222 push(@x, $car); $car = 0;
224 $y = $y * $dd + $car;
225 $y -= ($car = int($y * 1e-5)) * 1e5;
231 @q = (); ($v2,$v1) = @y[-2,-1];
233 ($u2,$u1,$u0) = @x[-3..-1];
234 $q = (($u0 == $v1) ? 99999 : int(($u0*1e5+$u1)/$v1));
235 --$q while ($v2*$q > ($u0*1e5+$u1-$q*$v1)*1e5+$u2);
237 ($car, $bar) = (0,0);
238 for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
239 $prd = $q * $y[$y] + $car;
240 $prd -= ($car = int($prd * 1e-5)) * 1e5;
241 $x[$x] += 1e5 if ($bar = (($x[$x] -= $prd + $bar) < 0));
243 if ($x[$#x] < $car + $bar) {
245 for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
247 if ($car = (($x[$x] += $y[$y] + $car) > 1e5));
251 pop(@x); unshift(@q, $q);
257 for $x (reverse @x) {
258 $prd = $car * 1e5 + $x;
259 $car = $prd - ($tmp = int($prd / $dd)) * $dd;
266 (&external($sr, @q), &external($srem, @d, 0));