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1 | package bigint; |
a6d71656 |
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 | # |
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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 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 | # |
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44 | |
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45 | # overcome a floating point problem on certain osnames (posix-bc, os390) |
46 | BEGIN { |
47 | my $x = 100000.0; |
48 | my $use_mult = int($x*1e-5)*1e5 == $x ? 1 : 0; |
49 | } |
50 | |
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51 | $zero = 0; |
52 | |
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53 | \f |
54 | # normalize string form of number. Strip leading zeros. Strip any |
55 | # white space and add a sign, if missing. |
56 | # Strings that are not numbers result the value 'NaN'. |
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57 | |
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58 | sub main'bnorm { #(num_str) return num_str |
59 | local($_) = @_; |
60 | s/\s+//g; # strip white space |
61 | if (s/^([+-]?)0*(\d+)$/$1$2/) { # test if number |
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62 | substr($_,$[,0) = '+' unless $1; # Add missing sign |
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63 | s/^-0/+0/; |
64 | $_; |
65 | } else { |
66 | 'NaN'; |
67 | } |
68 | } |
69 | |
70 | # Convert a number from string format to internal base 100000 format. |
71 | # Assumes normalized value as input. |
72 | sub internal { #(num_str) return int_num_array |
73 | local($d) = @_; |
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74 | ($is,$il) = (substr($d,$[,1),length($d)-2); |
75 | substr($d,$[,1) = ''; |
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76 | ($is, reverse(unpack("a" . ($il%5+1) . ("a5" x ($il/5)), $d))); |
77 | } |
78 | |
79 | # Convert a number from internal base 100000 format to string format. |
80 | # This routine scribbles all over input array. |
81 | sub external { #(int_num_array) return num_str |
82 | $es = shift; |
83 | grep($_ > 9999 || ($_ = substr('0000'.$_,-5)), @_); # zero pad |
84 | &'bnorm(join('', $es, reverse(@_))); # reverse concat and normalize |
85 | } |
86 | |
87 | # Negate input value. |
88 | sub main'bneg { #(num_str) return num_str |
89 | local($_) = &'bnorm(@_); |
90 | vec($_,0,8) ^= ord('+') ^ ord('-') unless $_ eq '+0'; |
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91 | s/^./N/ unless /^[-+]/; # works both in ASCII and EBCDIC |
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92 | $_; |
93 | } |
94 | |
95 | # Returns the absolute value of the input. |
96 | sub main'babs { #(num_str) return num_str |
97 | &abs(&'bnorm(@_)); |
98 | } |
99 | |
100 | sub abs { # post-normalized abs for internal use |
101 | local($_) = @_; |
102 | s/^-/+/; |
103 | $_; |
104 | } |
105 | \f |
106 | # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort) |
107 | sub main'bcmp { #(num_str, num_str) return cond_code |
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108 | local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1])); |
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109 | if ($x eq 'NaN') { |
110 | undef; |
111 | } elsif ($y eq 'NaN') { |
112 | undef; |
113 | } else { |
114 | &cmp($x,$y); |
115 | } |
116 | } |
117 | |
118 | sub cmp { # post-normalized compare for internal use |
119 | local($cx, $cy) = @_; |
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120 | return 0 if ($cx eq $cy); |
121 | |
122 | local($sx, $sy) = (substr($cx, 0, 1), substr($cy, 0, 1)); |
123 | local($ld); |
124 | |
125 | if ($sx eq '+') { |
126 | return 1 if ($sy eq '-' || $cy eq '+0'); |
127 | $ld = length($cx) - length($cy); |
128 | return $ld if ($ld); |
129 | return $cx cmp $cy; |
130 | } else { # $sx eq '-' |
131 | return -1 if ($sy eq '+'); |
132 | $ld = length($cy) - length($cx); |
133 | return $ld if ($ld); |
134 | return $cy cmp $cx; |
135 | } |
136 | |
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137 | } |
138 | |
139 | sub main'badd { #(num_str, num_str) return num_str |
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140 | local(*x, *y); ($x, $y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1])); |
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141 | if ($x eq 'NaN') { |
142 | 'NaN'; |
143 | } elsif ($y eq 'NaN') { |
144 | 'NaN'; |
145 | } else { |
146 | @x = &internal($x); # convert to internal form |
147 | @y = &internal($y); |
148 | local($sx, $sy) = (shift @x, shift @y); # get signs |
149 | if ($sx eq $sy) { |
150 | &external($sx, &add(*x, *y)); # if same sign add |
151 | } else { |
152 | ($x, $y) = (&abs($x),&abs($y)); # make abs |
153 | if (&cmp($y,$x) > 0) { |
154 | &external($sy, &sub(*y, *x)); |
155 | } else { |
156 | &external($sx, &sub(*x, *y)); |
157 | } |
158 | } |
159 | } |
160 | } |
161 | |
162 | sub main'bsub { #(num_str, num_str) return num_str |
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163 | &'badd($_[$[],&'bneg($_[$[+1])); |
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164 | } |
165 | |
166 | # GCD -- Euclids algorithm Knuth Vol 2 pg 296 |
167 | sub main'bgcd { #(num_str, num_str) return num_str |
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168 | local($x,$y) = (&'bnorm($_[$[]),&'bnorm($_[$[+1])); |
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169 | if ($x eq 'NaN' || $y eq 'NaN') { |
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170 | 'NaN'; |
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171 | } else { |
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172 | ($x, $y) = ($y,&'bmod($x,$y)) while $y ne '+0'; |
173 | $x; |
174 | } |
175 | } |
176 | \f |
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177 | # routine to add two base 1e5 numbers |
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178 | # stolen from Knuth Vol 2 Algorithm A pg 231 |
179 | # there are separate routines to add and sub as per Kunth pg 233 |
180 | sub add { #(int_num_array, int_num_array) return int_num_array |
181 | local(*x, *y) = @_; |
182 | $car = 0; |
183 | for $x (@x) { |
184 | last unless @y || $car; |
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185 | $x -= 1e5 if $car = (($x += shift(@y) + $car) >= 1e5) ? 1 : 0; |
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186 | } |
187 | for $y (@y) { |
188 | last unless $car; |
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189 | $y -= 1e5 if $car = (($y += $car) >= 1e5) ? 1 : 0; |
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190 | } |
191 | (@x, @y, $car); |
192 | } |
193 | |
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194 | # subtract base 1e5 numbers -- stolen from Knuth Vol 2 pg 232, $x > $y |
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195 | sub sub { #(int_num_array, int_num_array) return int_num_array |
196 | local(*sx, *sy) = @_; |
197 | $bar = 0; |
198 | for $sx (@sx) { |
199 | last unless @y || $bar; |
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200 | $sx += 1e5 if $bar = (($sx -= shift(@sy) + $bar) < 0); |
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201 | } |
202 | @sx; |
203 | } |
204 | |
205 | # multiply two numbers -- stolen from Knuth Vol 2 pg 233 |
206 | sub main'bmul { #(num_str, num_str) return num_str |
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207 | local(*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1])); |
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208 | if ($x eq 'NaN') { |
209 | 'NaN'; |
210 | } elsif ($y eq 'NaN') { |
211 | 'NaN'; |
212 | } else { |
213 | @x = &internal($x); |
214 | @y = &internal($y); |
215 | local($signr) = (shift @x ne shift @y) ? '-' : '+'; |
216 | @prod = (); |
217 | for $x (@x) { |
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218 | ($car, $cty) = (0, $[); |
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219 | for $y (@y) { |
220 | $prod = $x * $y + $prod[$cty] + $car; |
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221 | if ($use_mult) { |
222 | $prod[$cty++] = |
223 | $prod - ($car = int($prod * 1e-5)) * 1e5; |
224 | } |
225 | else { |
226 | $prod[$cty++] = |
227 | $prod - ($car = int($prod / 1e5)) * 1e5; |
228 | } |
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229 | } |
230 | $prod[$cty] += $car if $car; |
231 | $x = shift @prod; |
232 | } |
233 | &external($signr, @x, @prod); |
234 | } |
235 | } |
236 | |
237 | # modulus |
238 | sub main'bmod { #(num_str, num_str) return num_str |
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239 | (&'bdiv(@_))[$[+1]; |
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240 | } |
241 | \f |
242 | sub main'bdiv { #(dividend: num_str, divisor: num_str) return num_str |
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243 | local (*x, *y); ($x, $y) = (&'bnorm($_[$[]), &'bnorm($_[$[+1])); |
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244 | return wantarray ? ('NaN','NaN') : 'NaN' |
245 | if ($x eq 'NaN' || $y eq 'NaN' || $y eq '+0'); |
246 | return wantarray ? ('+0',$x) : '+0' if (&cmp(&abs($x),&abs($y)) < 0); |
247 | @x = &internal($x); @y = &internal($y); |
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248 | $srem = $y[$[]; |
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249 | $sr = (shift @x ne shift @y) ? '-' : '+'; |
250 | $car = $bar = $prd = 0; |
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251 | if (($dd = int(1e5/($y[$#y]+1))) != 1) { |
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252 | for $x (@x) { |
253 | $x = $x * $dd + $car; |
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254 | if ($use_mult) { |
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255 | $x -= ($car = int($x * 1e-5)) * 1e5; |
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256 | } |
257 | else { |
258 | $x -= ($car = int($x / 1e5)) * 1e5; |
259 | } |
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260 | } |
261 | push(@x, $car); $car = 0; |
262 | for $y (@y) { |
263 | $y = $y * $dd + $car; |
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264 | if ($use_mult) { |
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265 | $y -= ($car = int($y * 1e-5)) * 1e5; |
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266 | } |
267 | else { |
268 | $y -= ($car = int($y / 1e5)) * 1e5; |
269 | } |
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270 | } |
271 | } |
272 | else { |
273 | push(@x, 0); |
274 | } |
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275 | @q = (); ($v2,$v1) = @y[-2,-1]; |
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276 | while ($#x > $#y) { |
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277 | ($u2,$u1,$u0) = @x[-3..-1]; |
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278 | $q = (($u0 == $v1) ? 99999 : int(($u0*1e5+$u1)/$v1)); |
279 | --$q while ($v2*$q > ($u0*1e5+$u1-$q*$v1)*1e5+$u2); |
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280 | if ($q) { |
281 | ($car, $bar) = (0,0); |
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282 | for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) { |
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283 | $prd = $q * $y[$y] + $car; |
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284 | if ($use_mult) { |
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285 | $prd -= ($car = int($prd * 1e-5)) * 1e5; |
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286 | } |
287 | else { |
288 | $prd -= ($car = int($prd / 1e5)) * 1e5; |
289 | } |
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290 | $x[$x] += 1e5 if ($bar = (($x[$x] -= $prd + $bar) < 0)); |
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291 | } |
292 | if ($x[$#x] < $car + $bar) { |
293 | $car = 0; --$q; |
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294 | for ($y = $[, $x = $#x-$#y+$[-1; $y <= $#y; ++$y,++$x) { |
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295 | $x[$x] -= 1e5 |
296 | if ($car = (($x[$x] += $y[$y] + $car) > 1e5)); |
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297 | } |
298 | } |
299 | } |
300 | pop(@x); unshift(@q, $q); |
301 | } |
302 | if (wantarray) { |
303 | @d = (); |
304 | if ($dd != 1) { |
305 | $car = 0; |
306 | for $x (reverse @x) { |
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307 | $prd = $car * 1e5 + $x; |
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308 | $car = $prd - ($tmp = int($prd / $dd)) * $dd; |
309 | unshift(@d, $tmp); |
310 | } |
311 | } |
312 | else { |
313 | @d = @x; |
314 | } |
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315 | (&external($sr, @q), &external($srem, @d, $zero)); |
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316 | } else { |
317 | &external($sr, @q); |
318 | } |
319 | } |
320 | 1; |