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