This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
untodo the no-longer-failing todo test for rgs' patch
[perl5.git] / lib / bigint.pl
CommitLineData
5303340c 1package bigint;
a6d71656
GS
2#
3# This library is no longer being maintained, and is included for backward
4# compatibility with Perl 4 programs which may require it.
5#
6# In particular, this should not be used as an example of modern Perl
7# programming techniques.
b6dbc3e0
S
8# This legacy library is deprecated and will be removed in a future
9# release of perl.
a6d71656
GS
10#
11# Suggested alternative: Math::BigInt
b6dbc3e0
S
12
13warn( "The 'bigint.pl' legacy library is deprecated and will be"
14 . " removed in the next major release of perl. Please use the"
15 . " Math::BigInt module instead." );
16
5303340c
LW
17# arbitrary size integer math package
18#
19# by Mark Biggar
20#
21# Canonical Big integer value are strings of the form
22# /^[+-]\d+$/ with leading zeros suppressed
23# Input values to these routines may be strings of the form
24# /^\s*[+-]?[\d\s]+$/.
25# Examples:
26# '+0' canonical zero value
27# ' -123 123 123' canonical value '-123123123'
28# '1 23 456 7890' canonical value '+1234567890'
d1be9408 29# Output values always in canonical form
5303340c
LW
30#
31# Actual math is done in an internal format consisting of an array
32# whose first element is the sign (/^[+-]$/) and whose remaining
33# elements are base 100000 digits with the least significant digit first.
34# The string 'NaN' is used to represent the result when input arguments
35# are not numbers, as well as the result of dividing by zero
36#
37# routines provided are:
38#
39# bneg(BINT) return BINT negation
40# babs(BINT) return BINT absolute value
41# bcmp(BINT,BINT) return CODE compare numbers (undef,<0,=0,>0)
42# badd(BINT,BINT) return BINT addition
43# bsub(BINT,BINT) return BINT subtraction
44# bmul(BINT,BINT) return BINT multiplication
45# bdiv(BINT,BINT) return (BINT,BINT) division (quo,rem) just quo if scalar
46# bmod(BINT,BINT) return BINT modulus
47# bgcd(BINT,BINT) return BINT greatest common divisor
48# bnorm(BINT) return BINT normalization
49#
8990e307 50
1f45ae4a
PP
51# overcome a floating point problem on certain osnames (posix-bc, os390)
52BEGIN {
53 my $x = 100000.0;
54 my $use_mult = int($x*1e-5)*1e5 == $x ? 1 : 0;
55}
56
8990e307
LW
57$zero = 0;
58
5303340c
LW
59\f
60# normalize string form of number. Strip leading zeros. Strip any
61# white space and add a sign, if missing.
62# Strings that are not numbers result the value 'NaN'.
8990e307 63
5303340c
LW
64sub main'bnorm { #(num_str) return num_str
65 local($_) = @_;
66 s/\s+//g; # strip white space
67 if (s/^([+-]?)0*(\d+)$/$1$2/) { # test if number
79072805 68 substr($_,$[,0) = '+' unless $1; # Add missing sign
5303340c
LW
69 s/^-0/+0/;
70 $_;
71 } else {
72 'NaN';
73 }
74}
75
76# Convert a number from string format to internal base 100000 format.
77# Assumes normalized value as input.
78sub internal { #(num_str) return int_num_array
79 local($d) = @_;
79072805
LW
80 ($is,$il) = (substr($d,$[,1),length($d)-2);
81 substr($d,$[,1) = '';
5303340c
LW
82 ($is, reverse(unpack("a" . ($il%5+1) . ("a5" x ($il/5)), $d)));
83}
84
85# Convert a number from internal base 100000 format to string format.
86# This routine scribbles all over input array.
87sub external { #(int_num_array) return num_str
88 $es = shift;
89 grep($_ > 9999 || ($_ = substr('0000'.$_,-5)), @_); # zero pad
90 &'bnorm(join('', $es, reverse(@_))); # reverse concat and normalize
91}
92
93# Negate input value.
94sub main'bneg { #(num_str) return num_str
95 local($_) = &'bnorm(@_);
96 vec($_,0,8) ^= ord('+') ^ ord('-') unless $_ eq '+0';
9d116dd7 97 s/^./N/ unless /^[-+]/; # works both in ASCII and EBCDIC
5303340c
LW
98 $_;
99}
100
101# Returns the absolute value of the input.
102sub main'babs { #(num_str) return num_str
103 &abs(&'bnorm(@_));
104}
105
106sub abs { # post-normalized abs for internal use
107 local($_) = @_;
108 s/^-/+/;
109 $_;
110}
111\f
112# Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
113sub main'bcmp { #(num_str, num_str) return cond_code
79072805 114 local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
5303340c
LW
115 if ($x eq 'NaN') {
116 undef;
117 } elsif ($y eq 'NaN') {
118 undef;
119 } else {
120 &cmp($x,$y);
121 }
122}
123
124sub cmp { # post-normalized compare for internal use
125 local($cx, $cy) = @_;
1e2e1ae8
JH
126 return 0 if ($cx eq $cy);
127
128 local($sx, $sy) = (substr($cx, 0, 1), substr($cy, 0, 1));
129 local($ld);
130
131 if ($sx eq '+') {
132 return 1 if ($sy eq '-' || $cy eq '+0');
133 $ld = length($cx) - length($cy);
134 return $ld if ($ld);
135 return $cx cmp $cy;
136 } else { # $sx eq '-'
137 return -1 if ($sy eq '+');
138 $ld = length($cy) - length($cx);
139 return $ld if ($ld);
140 return $cy cmp $cx;
141 }
142
5303340c
LW
143}
144
145sub main'badd { #(num_str, num_str) return num_str
79072805 146 local(*x, *y); ($x, $y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
5303340c
LW
147 if ($x eq 'NaN') {
148 'NaN';
149 } elsif ($y eq 'NaN') {
150 'NaN';
151 } else {
152 @x = &internal($x); # convert to internal form
153 @y = &internal($y);
154 local($sx, $sy) = (shift @x, shift @y); # get signs
155 if ($sx eq $sy) {
156 &external($sx, &add(*x, *y)); # if same sign add
157 } else {
158 ($x, $y) = (&abs($x),&abs($y)); # make abs
159 if (&cmp($y,$x) > 0) {
160 &external($sy, &sub(*y, *x));
161 } else {
162 &external($sx, &sub(*x, *y));
163 }
164 }
165 }
166}
167
168sub main'bsub { #(num_str, num_str) return num_str
79072805 169 &'badd($_[$[],&'bneg($_[$[+1]));
5303340c
LW
170}
171
172# GCD -- Euclids algorithm Knuth Vol 2 pg 296
173sub main'bgcd { #(num_str, num_str) return num_str
79072805 174 local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
68decaef 175 if ($x eq 'NaN' || $y eq 'NaN') {
5303340c 176 'NaN';
68decaef 177 } else {
5303340c
LW
178 ($x, $y) = ($y,&'bmod($x,$y)) while $y ne '+0';
179 $x;
180 }
181}
182\f
68decaef 183# routine to add two base 1e5 numbers
5303340c
LW
184# stolen from Knuth Vol 2 Algorithm A pg 231
185# there are separate routines to add and sub as per Kunth pg 233
186sub add { #(int_num_array, int_num_array) return int_num_array
187 local(*x, *y) = @_;
188 $car = 0;
189 for $x (@x) {
190 last unless @y || $car;
55497cff 191 $x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5) ? 1 : 0;
5303340c
LW
192 }
193 for $y (@y) {
194 last unless $car;
55497cff 195 $y -= 1e5 if $car = (($y += $car) >= 1e5) ? 1 : 0;
5303340c
LW
196 }
197 (@x, @y, $car);
198}
199
68decaef 200# subtract base 1e5 numbers -- stolen from Knuth Vol 2 pg 232, $x > $y
5303340c
LW
201sub sub { #(int_num_array, int_num_array) return int_num_array
202 local(*sx, *sy) = @_;
203 $bar = 0;
204 for $sx (@sx) {
205 last unless @y || $bar;
e334a159 206 $sx += 1e5 if $bar = (($sx -= shift(@sy) + $bar) < 0);
5303340c
LW
207 }
208 @sx;
209}
210
211# multiply two numbers -- stolen from Knuth Vol 2 pg 233
212sub main'bmul { #(num_str, num_str) return num_str
79072805 213 local(*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
5303340c
LW
214 if ($x eq 'NaN') {
215 'NaN';
216 } elsif ($y eq 'NaN') {
217 'NaN';
218 } else {
219 @x = &internal($x);
220 @y = &internal($y);
221 local($signr) = (shift @x ne shift @y) ? '-' : '+';
222 @prod = ();
223 for $x (@x) {
79072805 224 ($car, $cty) = (0, $[);
5303340c
LW
225 for $y (@y) {
226 $prod = $x * $y + $prod[$cty] + $car;
1f45ae4a
PP
227 if ($use_mult) {
228 $prod[$cty++] =
229 $prod - ($car = int($prod * 1e-5)) * 1e5;
230 }
231 else {
232 $prod[$cty++] =
233 $prod - ($car = int($prod / 1e5)) * 1e5;
234 }
5303340c
LW
235 }
236 $prod[$cty] += $car if $car;
237 $x = shift @prod;
238 }
239 &external($signr, @x, @prod);
240 }
241}
242
243# modulus
244sub main'bmod { #(num_str, num_str) return num_str
79072805 245 (&'bdiv(@_))[$[+1];
5303340c
LW
246}
247\f
248sub main'bdiv { #(dividend: num_str, divisor: num_str) return num_str
79072805 249 local (*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
5303340c
LW
250 return wantarray ? ('NaN','NaN') : 'NaN'
251 if ($x eq 'NaN' || $y eq 'NaN' || $y eq '+0');
252 return wantarray ? ('+0',$x) : '+0' if (&cmp(&abs($x),&abs($y)) < 0);
253 @x = &internal($x); @y = &internal($y);
79072805 254 $srem = $y[$[];
5303340c
LW
255 $sr = (shift @x ne shift @y) ? '-' : '+';
256 $car = $bar = $prd = 0;
68decaef 257 if (($dd = int(1e5/($y[$#y]+1))) != 1) {
5303340c
LW
258 for $x (@x) {
259 $x = $x * $dd + $car;
1f45ae4a 260 if ($use_mult) {
68decaef 261 $x -= ($car = int($x * 1e-5)) * 1e5;
1f45ae4a
PP
262 }
263 else {
264 $x -= ($car = int($x / 1e5)) * 1e5;
265 }
5303340c
LW
266 }
267 push(@x, $car); $car = 0;
268 for $y (@y) {
269 $y = $y * $dd + $car;
1f45ae4a 270 if ($use_mult) {
68decaef 271 $y -= ($car = int($y * 1e-5)) * 1e5;
1f45ae4a
PP
272 }
273 else {
274 $y -= ($car = int($y / 1e5)) * 1e5;
275 }
5303340c
LW
276 }
277 }
278 else {
279 push(@x, 0);
280 }
ed6116ce 281 @q = (); ($v2,$v1) = @y[-2,-1];
5303340c 282 while ($#x > $#y) {
ed6116ce 283 ($u2,$u1,$u0) = @x[-3..-1];
68decaef
LW
284 $q = (($u0 == $v1) ? 99999 : int(($u0*1e5+$u1)/$v1));
285 --$q while ($v2*$q > ($u0*1e5+$u1-$q*$v1)*1e5+$u2);
5303340c
LW
286 if ($q) {
287 ($car, $bar) = (0,0);
79072805 288 for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
5303340c 289 $prd = $q * $y[$y] + $car;
1f45ae4a 290 if ($use_mult) {
68decaef 291 $prd -= ($car = int($prd * 1e-5)) * 1e5;
1f45ae4a
PP
292 }
293 else {
294 $prd -= ($car = int($prd / 1e5)) * 1e5;
295 }
68decaef 296 $x[$x] += 1e5 if ($bar = (($x[$x] -= $prd + $bar) < 0));
5303340c
LW
297 }
298 if ($x[$#x] < $car + $bar) {
299 $car = 0; --$q;
79072805 300 for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
68decaef
LW
301 $x[$x] -= 1e5
302 if ($car = (($x[$x] += $y[$y] + $car) > 1e5));
5303340c
LW
303 }
304 }
305 }
306 pop(@x); unshift(@q, $q);
307 }
308 if (wantarray) {
309 @d = ();
310 if ($dd != 1) {
311 $car = 0;
312 for $x (reverse @x) {
68decaef 313 $prd = $car * 1e5 + $x;
5303340c
LW
314 $car = $prd - ($tmp = int($prd / $dd)) * $dd;
315 unshift(@d, $tmp);
316 }
317 }
318 else {
319 @d = @x;
320 }
8990e307 321 (&external($sr, @q), &external($srem, @d, $zero));
5303340c
LW
322 } else {
323 &external($sr, @q);
324 }
325}
3261;