source: for-distributions/trunk/bin/windows/perl/lib/bigint.pl@ 14489

Last change on this file since 14489 was 14489, checked in by oranfry, 17 years ago

upgrading to perl 5.8

File size: 8.7 KB
Line 
1package bigint;
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.
8#
9# Suggested alternative: Math::BigInt
10#
11# arbitrary size integer math package
12#
13# by Mark Biggar
14#
15# Canonical Big integer value are strings of the form
16# /^[+-]\d+$/ with leading zeros suppressed
17# Input values to these routines may be strings of the form
18# /^\s*[+-]?[\d\s]+$/.
19# Examples:
20# '+0' canonical zero value
21# ' -123 123 123' canonical value '-123123123'
22# '1 23 456 7890' canonical value '+1234567890'
23# Output values always in canonical form
24#
25# Actual math is done in an internal format consisting of an array
26# whose first element is the sign (/^[+-]$/) and whose remaining
27# elements are base 100000 digits with the least significant digit first.
28# The string 'NaN' is used to represent the result when input arguments
29# are not numbers, as well as the result of dividing by zero
30#
31# routines provided are:
32#
33# bneg(BINT) return BINT negation
34# babs(BINT) return BINT absolute value
35# bcmp(BINT,BINT) return CODE compare numbers (undef,<0,=0,>0)
36# badd(BINT,BINT) return BINT addition
37# bsub(BINT,BINT) return BINT subtraction
38# bmul(BINT,BINT) return BINT multiplication
39# bdiv(BINT,BINT) return (BINT,BINT) division (quo,rem) just quo if scalar
40# bmod(BINT,BINT) return BINT modulus
41# bgcd(BINT,BINT) return BINT greatest common divisor
42# bnorm(BINT) return BINT normalization
43#
44
45# overcome a floating point problem on certain osnames (posix-bc, os390)
46BEGIN {
47 my $x = 100000.0;
48 my $use_mult = int($x*1e-5)*1e5 == $x ? 1 : 0;
49}
50
51$zero = 0;
52
53
54
55# normalize string form of number. Strip leading zeros. Strip any
56# white space and add a sign, if missing.
57# Strings that are not numbers result the value 'NaN'.
58
59sub main'bnorm { #(num_str) return num_str
60 local($_) = @_;
61 s/\s+//g; # strip white space
62 if (s/^([+-]?)0*(\d+)$/$1$2/) { # test if number
63 substr($_,$[,0) = '+' unless $1; # Add missing sign
64 s/^-0/+0/;
65 $_;
66 } else {
67 'NaN';
68 }
69}
70
71# Convert a number from string format to internal base 100000 format.
72# Assumes normalized value as input.
73sub internal { #(num_str) return int_num_array
74 local($d) = @_;
75 ($is,$il) = (substr($d,$[,1),length($d)-2);
76 substr($d,$[,1) = '';
77 ($is, reverse(unpack("a" . ($il%5+1) . ("a5" x ($il/5)), $d)));
78}
79
80# Convert a number from internal base 100000 format to string format.
81# This routine scribbles all over input array.
82sub external { #(int_num_array) return num_str
83 $es = shift;
84 grep($_ > 9999 || ($_ = substr('0000'.$_,-5)), @_); # zero pad
85 &'bnorm(join('', $es, reverse(@_))); # reverse concat and normalize
86}
87
88# Negate input value.
89sub main'bneg { #(num_str) return num_str
90 local($_) = &'bnorm(@_);
91 vec($_,0,8) ^= ord('+') ^ ord('-') unless $_ eq '+0';
92 s/^./N/ unless /^[-+]/; # works both in ASCII and EBCDIC
93 $_;
94}
95
96# Returns the absolute value of the input.
97sub main'babs { #(num_str) return num_str
98 &abs(&'bnorm(@_));
99}
100
101sub abs { # post-normalized abs for internal use
102 local($_) = @_;
103 s/^-/+/;
104 $_;
105}
106
107
108# Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort)
109sub main'bcmp { #(num_str, num_str) return cond_code
110 local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
111 if ($x eq 'NaN') {
112 undef;
113 } elsif ($y eq 'NaN') {
114 undef;
115 } else {
116 &cmp($x,$y);
117 }
118}
119
120sub cmp { # post-normalized compare for internal use
121 local($cx, $cy) = @_;
122 return 0 if ($cx eq $cy);
123
124 local($sx, $sy) = (substr($cx, 0, 1), substr($cy, 0, 1));
125 local($ld);
126
127 if ($sx eq '+') {
128 return 1 if ($sy eq '-' || $cy eq '+0');
129 $ld = length($cx) - length($cy);
130 return $ld if ($ld);
131 return $cx cmp $cy;
132 } else { # $sx eq '-'
133 return -1 if ($sy eq '+');
134 $ld = length($cy) - length($cx);
135 return $ld if ($ld);
136 return $cy cmp $cx;
137 }
138
139}
140
141sub main'badd { #(num_str, num_str) return num_str
142 local(*x, *y); ($x, $y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
143 if ($x eq 'NaN') {
144 'NaN';
145 } elsif ($y eq 'NaN') {
146 'NaN';
147 } else {
148 @x = &internal($x); # convert to internal form
149 @y = &internal($y);
150 local($sx, $sy) = (shift @x, shift @y); # get signs
151 if ($sx eq $sy) {
152 &external($sx, &add(*x, *y)); # if same sign add
153 } else {
154 ($x, $y) = (&abs($x),&abs($y)); # make abs
155 if (&cmp($y,$x) > 0) {
156 &external($sy, &sub(*y, *x));
157 } else {
158 &external($sx, &sub(*x, *y));
159 }
160 }
161 }
162}
163
164sub main'bsub { #(num_str, num_str) return num_str
165 &'badd($_[$[],&'bneg($_[$[+1]));
166}
167
168# GCD -- Euclids algorithm Knuth Vol 2 pg 296
169sub main'bgcd { #(num_str, num_str) return num_str
170 local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1]));
171 if ($x eq 'NaN' || $y eq 'NaN') {
172 'NaN';
173 } else {
174 ($x, $y) = ($y,&'bmod($x,$y)) while $y ne '+0';
175 $x;
176 }
177}
178
179
180# routine to add two base 1e5 numbers
181# stolen from Knuth Vol 2 Algorithm A pg 231
182# there are separate routines to add and sub as per Kunth pg 233
183sub add { #(int_num_array, int_num_array) return int_num_array
184 local(*x, *y) = @_;
185 $car = 0;
186 for $x (@x) {
187 last unless @y || $car;
188 $x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5) ? 1 : 0;
189 }
190 for $y (@y) {
191 last unless $car;
192 $y -= 1e5 if $car = (($y += $car) >= 1e5) ? 1 : 0;
193 }
194 (@x, @y, $car);
195}
196
197# subtract base 1e5 numbers -- stolen from Knuth Vol 2 pg 232, $x > $y
198sub sub { #(int_num_array, int_num_array) return int_num_array
199 local(*sx, *sy) = @_;
200 $bar = 0;
201 for $sx (@sx) {
202 last unless @y || $bar;
203 $sx += 1e5 if $bar = (($sx -= shift(@sy) + $bar) < 0);
204 }
205 @sx;
206}
207
208# multiply two numbers -- stolen from Knuth Vol 2 pg 233
209sub main'bmul { #(num_str, num_str) return num_str
210 local(*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
211 if ($x eq 'NaN') {
212 'NaN';
213 } elsif ($y eq 'NaN') {
214 'NaN';
215 } else {
216 @x = &internal($x);
217 @y = &internal($y);
218 local($signr) = (shift @x ne shift @y) ? '-' : '+';
219 @prod = ();
220 for $x (@x) {
221 ($car, $cty) = (0, $[);
222 for $y (@y) {
223 $prod = $x * $y + $prod[$cty] + $car;
224 if ($use_mult) {
225 $prod[$cty++] =
226 $prod - ($car = int($prod * 1e-5)) * 1e5;
227 }
228 else {
229 $prod[$cty++] =
230 $prod - ($car = int($prod / 1e5)) * 1e5;
231 }
232 }
233 $prod[$cty] += $car if $car;
234 $x = shift @prod;
235 }
236 &external($signr, @x, @prod);
237 }
238}
239
240# modulus
241sub main'bmod { #(num_str, num_str) return num_str
242 (&'bdiv(@_))[$[+1];
243}
244
245
246sub main'bdiv { #(dividend: num_str, divisor: num_str) return num_str
247 local (*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1]));
248 return wantarray ? ('NaN','NaN') : 'NaN'
249 if ($x eq 'NaN' || $y eq 'NaN' || $y eq '+0');
250 return wantarray ? ('+0',$x) : '+0' if (&cmp(&abs($x),&abs($y)) < 0);
251 @x = &internal($x); @y = &internal($y);
252 $srem = $y[$[];
253 $sr = (shift @x ne shift @y) ? '-' : '+';
254 $car = $bar = $prd = 0;
255 if (($dd = int(1e5/($y[$#y]+1))) != 1) {
256 for $x (@x) {
257 $x = $x * $dd + $car;
258 if ($use_mult) {
259 $x -= ($car = int($x * 1e-5)) * 1e5;
260 }
261 else {
262 $x -= ($car = int($x / 1e5)) * 1e5;
263 }
264 }
265 push(@x, $car); $car = 0;
266 for $y (@y) {
267 $y = $y * $dd + $car;
268 if ($use_mult) {
269 $y -= ($car = int($y * 1e-5)) * 1e5;
270 }
271 else {
272 $y -= ($car = int($y / 1e5)) * 1e5;
273 }
274 }
275 }
276 else {
277 push(@x, 0);
278 }
279 @q = (); ($v2,$v1) = @y[-2,-1];
280 while ($#x > $#y) {
281 ($u2,$u1,$u0) = @x[-3..-1];
282 $q = (($u0 == $v1) ? 99999 : int(($u0*1e5+$u1)/$v1));
283 --$q while ($v2*$q > ($u0*1e5+$u1-$q*$v1)*1e5+$u2);
284 if ($q) {
285 ($car, $bar) = (0,0);
286 for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
287 $prd = $q * $y[$y] + $car;
288 if ($use_mult) {
289 $prd -= ($car = int($prd * 1e-5)) * 1e5;
290 }
291 else {
292 $prd -= ($car = int($prd / 1e5)) * 1e5;
293 }
294 $x[$x] += 1e5 if ($bar = (($x[$x] -= $prd + $bar) < 0));
295 }
296 if ($x[$#x] < $car + $bar) {
297 $car = 0; --$q;
298 for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) {
299 $x[$x] -= 1e5
300 if ($car = (($x[$x] += $y[$y] + $car) > 1e5));
301 }
302 }
303 }
304 pop(@x); unshift(@q, $q);
305 }
306 if (wantarray) {
307 @d = ();
308 if ($dd != 1) {
309 $car = 0;
310 for $x (reverse @x) {
311 $prd = $car * 1e5 + $x;
312 $car = $prd - ($tmp = int($prd / $dd)) * $dd;
313 unshift(@d, $tmp);
314 }
315 }
316 else {
317 @d = @x;
318 }
319 (&external($sr, @q), &external($srem, @d, $zero));
320 } else {
321 &external($sr, @q);
322 }
323}
3241;
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