diff options
Diffstat (limited to 'lib/Math/BigInt.pm')
| -rw-r--r-- | lib/Math/BigInt.pm | 123 |
1 files changed, 80 insertions, 43 deletions
diff --git a/lib/Math/BigInt.pm b/lib/Math/BigInt.pm index 8c0ca4e6d4..68856aea6e 100644 --- a/lib/Math/BigInt.pm +++ b/lib/Math/BigInt.pm @@ -1,7 +1,6 @@ package Math::BigInt; -%OVERLOAD = ( - # Anonymous subroutines: +use overload '+' => sub {new Math::BigInt &badd}, '-' => sub {new Math::BigInt $_[2]? bsub($_[1],${$_[0]}) : bsub(${$_[0]},$_[1])}, @@ -23,57 +22,24 @@ package Math::BigInt; qw( "" stringify 0+ numify) # Order of arguments unsignificant -); +; $NaNOK=1; sub new { - my $foo = bnorm($_[1]); + my($class) = shift; + my($foo) = bnorm(shift); die "Not a number initialized to Math::BigInt" if !$NaNOK && $foo eq "NaN"; - bless \$foo; + bless \$foo, $class; } sub stringify { "${$_[0]}" } sub numify { 0 + "${$_[0]}" } # Not needed, additional overhead # comparing to direct compilation based on # stringify -# arbitrary size integer math package -# -# by Mark Biggar -# -# Canonical Big integer value are strings of the form -# /^[+-]\d+$/ with leading zeros suppressed -# Input values to these routines may be strings of the form -# /^\s*[+-]?[\d\s]+$/. -# Examples: -# '+0' canonical zero value -# ' -123 123 123' canonical value '-123123123' -# '1 23 456 7890' canonical value '+1234567890' -# Output values always always in canonical form -# -# Actual math is done in an internal format consisting of an array -# whose first element is the sign (/^[+-]$/) and whose remaining -# elements are base 100000 digits with the least significant digit first. -# The string 'NaN' is used to represent the result when input arguments -# are not numbers, as well as the result of dividing by zero -# -# routines provided are: -# -# bneg(BINT) return BINT negation -# babs(BINT) return BINT absolute value -# bcmp(BINT,BINT) return CODE compare numbers (undef,<0,=0,>0) -# badd(BINT,BINT) return BINT addition -# bsub(BINT,BINT) return BINT subtraction -# bmul(BINT,BINT) return BINT multiplication -# bdiv(BINT,BINT) return (BINT,BINT) division (quo,rem) just quo if scalar -# bmod(BINT,BINT) return BINT modulus -# bgcd(BINT,BINT) return BINT greatest common divisor -# bnorm(BINT) return BINT normalization -# - $zero = 0; - + # normalize string form of number. Strip leading zeros. Strip any # white space and add a sign, if missing. # Strings that are not numbers result the value 'NaN'. @@ -125,7 +91,7 @@ sub abs { # post-normalized abs for internal use s/^-/+/; $_; } - + # Compares 2 values. Returns one of undef, <0, =0, >0. (suitable for sort) sub bcmp { #(num_str, num_str) return cond_code local($x,$y) = (&bnorm($_[$[]),&bnorm($_[$[+1])); @@ -186,7 +152,7 @@ sub bgcd { #(num_str, num_str) return num_str $x; } } - + # routine to add two base 1e5 numbers # stolen from Knuth Vol 2 Algorithm A pg 231 # there are separate routines to add and sub as per Kunth pg 233 @@ -252,7 +218,7 @@ sub mul { #(*int_num_array, *int_num_array) return int_num_array sub bmod { #(num_str, num_str) return num_str (&bdiv(@_))[$[+1]; } - + sub bdiv { #(dividend: num_str, divisor: num_str) return num_str local (*x, *y); ($x, $y) = (&bnorm($_[$[]), &bnorm($_[$[+1])); return wantarray ? ('NaN','NaN') : 'NaN' @@ -347,3 +313,74 @@ sub bpow { #(num_str, num_str) return num_str } 1; +__END__ + +=head1 NAME + +Math::BigInt - Arbitrary size integer math package + +=head1 SYNOPSIS + + use Math::BigInt; + $i = Math::BigInt->new($string); + + $i->bneg return BINT negation + $i->babs return BINT absolute value + $i->bcmp(BINT) return CODE compare numbers (undef,<0,=0,>0) + $i->badd(BINT) return BINT addition + $i->bsub(BINT) return BINT subtraction + $i->bmul(BINT) return BINT multiplication + $i->bdiv(BINT) return (BINT,BINT) division (quo,rem) just quo if scalar + $i->bmod(BINT) return BINT modulus + $i->bgcd(BINT) return BINT greatest common divisor + $i->bnorm return BINT normalization + +=head1 DESCRIPTION + +All basic math operations are overloaded if you declare your big +integers as + + $i = new Math::BigInt '123 456 789 123 456 789'; + + +=over 2 + +=item Canonical notation + +Big integer value are strings of the form C</^[+-]\d+$/> with leading +zeros suppressed. + +=item Input + +Input values to these routines may be strings of the form +C</^\s*[+-]?[\d\s]+$/>. + +=item Output + +Output values always always in canonical form + +=back + +Actual math is done in an internal format consisting of an array +whose first element is the sign (/^[+-]$/) and whose remaining +elements are base 100000 digits with the least significant digit first. +The string 'NaN' is used to represent the result when input arguments +are not numbers, as well as the result of dividing by zero. + +=head1 EXAMPLES + + '+0' canonical zero value + ' -123 123 123' canonical value '-123123123' + '1 23 456 7890' canonical value '+1234567890' + + +=head1 BUGS + +The current version of this module is a preliminary version of the +real thing that is currently (as of perl5.002) under development. + +=head1 AUTHOR + +Mark Biggar, overloaded interface by Ilya Zakharevich. + +=cut |