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Diffstat (limited to 'chromium/third_party/cygwin/lib/perl5/5.10/bigrat.pl')
| -rw-r--r-- | chromium/third_party/cygwin/lib/perl5/5.10/bigrat.pl | 155 |
1 files changed, 155 insertions, 0 deletions
diff --git a/chromium/third_party/cygwin/lib/perl5/5.10/bigrat.pl b/chromium/third_party/cygwin/lib/perl5/5.10/bigrat.pl new file mode 100644 index 00000000000..2d3738f805b --- /dev/null +++ b/chromium/third_party/cygwin/lib/perl5/5.10/bigrat.pl @@ -0,0 +1,155 @@ +package bigrat; +require "bigint.pl"; +# +# This library is no longer being maintained, and is included for backward +# compatibility with Perl 4 programs which may require it. +# +# In particular, this should not be used as an example of modern Perl +# programming techniques. +# +# Arbitrary size rational math package +# +# by Mark Biggar +# +# Input values to these routines consist of strings of the form +# m|^\s*[+-]?[\d\s]+(/[\d\s]+)?$|. +# Examples: +# "+0/1" canonical zero value +# "3" canonical value "+3/1" +# " -123/123 123" canonical value "-1/1001" +# "123 456/7890" canonical value "+20576/1315" +# Output values always include a sign and no leading zeros or +# white space. +# This package makes use of the bigint package. +# The string 'NaN' is used to represent the result when input arguments +# that are not numbers, as well as the result of dividing by zero and +# the sqrt of a negative number. +# Extreamly naive algorthims are used. +# +# Routines provided are: +# +# rneg(RAT) return RAT negation +# rabs(RAT) return RAT absolute value +# rcmp(RAT,RAT) return CODE compare numbers (undef,<0,=0,>0) +# radd(RAT,RAT) return RAT addition +# rsub(RAT,RAT) return RAT subtraction +# rmul(RAT,RAT) return RAT multiplication +# rdiv(RAT,RAT) return RAT division +# rmod(RAT) return (RAT,RAT) integer and fractional parts +# rnorm(RAT) return RAT normalization +# rsqrt(RAT, cycles) return RAT square root + +# Convert a number to the canonical string form m|^[+-]\d+/\d+|. +sub main'rnorm { #(string) return rat_num + local($_) = @_; + s/\s+//g; + if (m#^([+-]?\d+)(/(\d*[1-9]0*))?$#) { + &norm($1, $3 ? $3 : '+1'); + } else { + 'NaN'; + } +} + +# Normalize by reducing to lowest terms +sub norm { #(bint, bint) return rat_num + local($num,$dom) = @_; + if ($num eq 'NaN') { + 'NaN'; + } elsif ($dom eq 'NaN') { + 'NaN'; + } elsif ($dom =~ /^[+-]?0+$/) { + 'NaN'; + } else { + local($gcd) = &'bgcd($num,$dom); + $gcd =~ s/^-/+/; + if ($gcd ne '+1') { + $num = &'bdiv($num,$gcd); + $dom = &'bdiv($dom,$gcd); + } else { + $num = &'bnorm($num); + $dom = &'bnorm($dom); + } + substr($dom,$[,1) = ''; + "$num/$dom"; + } +} + +# negation +sub main'rneg { #(rat_num) return rat_num + local($_) = &'rnorm(@_); + tr/-+/+-/ if ($_ ne '+0/1'); + $_; +} + +# absolute value +sub main'rabs { #(rat_num) return $rat_num + local($_) = &'rnorm(@_); + substr($_,$[,1) = '+' unless $_ eq 'NaN'; + $_; +} + +# multipication +sub main'rmul { #(rat_num, rat_num) return rat_num + local($xn,$xd) = split('/',&'rnorm($_[$[])); + local($yn,$yd) = split('/',&'rnorm($_[$[+1])); + &norm(&'bmul($xn,$yn),&'bmul($xd,$yd)); +} + +# division +sub main'rdiv { #(rat_num, rat_num) return rat_num + local($xn,$xd) = split('/',&'rnorm($_[$[])); + local($yn,$yd) = split('/',&'rnorm($_[$[+1])); + &norm(&'bmul($xn,$yd),&'bmul($xd,$yn)); +} + +# addition +sub main'radd { #(rat_num, rat_num) return rat_num + local($xn,$xd) = split('/',&'rnorm($_[$[])); + local($yn,$yd) = split('/',&'rnorm($_[$[+1])); + &norm(&'badd(&'bmul($xn,$yd),&'bmul($yn,$xd)),&'bmul($xd,$yd)); +} + +# subtraction +sub main'rsub { #(rat_num, rat_num) return rat_num + local($xn,$xd) = split('/',&'rnorm($_[$[])); + local($yn,$yd) = split('/',&'rnorm($_[$[+1])); + &norm(&'bsub(&'bmul($xn,$yd),&'bmul($yn,$xd)),&'bmul($xd,$yd)); +} + +# comparison +sub main'rcmp { #(rat_num, rat_num) return cond_code + local($xn,$xd) = split('/',&'rnorm($_[$[])); + local($yn,$yd) = split('/',&'rnorm($_[$[+1])); + &bigint'cmp(&'bmul($xn,$yd),&'bmul($yn,$xd)); +} + +# int and frac parts +sub main'rmod { #(rat_num) return (rat_num,rat_num) + local($xn,$xd) = split('/',&'rnorm(@_)); + local($i,$f) = &'bdiv($xn,$xd); + if (wantarray) { + ("$i/1", "$f/$xd"); + } else { + "$i/1"; + } +} + +# square root by Newtons method. +# cycles specifies the number of iterations default: 5 +sub main'rsqrt { #(fnum_str[, cycles]) return fnum_str + local($x, $scale) = (&'rnorm($_[$[]), $_[$[+1]); + if ($x eq 'NaN') { + 'NaN'; + } elsif ($x =~ /^-/) { + 'NaN'; + } else { + local($gscale, $guess) = (0, '+1/1'); + $scale = 5 if (!$scale); + while ($gscale++ < $scale) { + $guess = &'rmul(&'radd($guess,&'rdiv($x,$guess)),"+1/2"); + } + "$guess"; # quotes necessary due to perl bug + } +} + +1; |