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