NAME
BaseCnv - A small perl module which exports functions to quickly
convert between any number bases
SYNOPSIS
use Math::BaseCnv;
@numb = ( 0, 2, 7, 42, 55, 57, 99, 127 );
@cycl = ( 10, 2, 64, 7, 10 );
print("Format: FromBass -> ToBass = ConvertedNumber\n");
foreach $n (@numb) {
printf("%-3d:", $n);
for($i = 1; $i < @cycl; $i++) {
$n = cnv($n, $cycl[$i - 1], $cycl[$i]);
printf("%3d->%-3d=%-7s", $cycl[$i - 1], $cycl[$i], $n);
}
print("\n");
}
-- execution output:
Format: FromBass -> ToBass = ConvertedNumber
0 : 10->2 =0 2->64 =0 64->7 =0 7->10 =0
2 : 10->2 =10 2->64 =2 64->7 =2 7->10 =2
7 : 10->2 =111 2->64 =7 64->7 =10 7->10 =7
42 : 10->2 =101010 2->64 =g 64->7 =60 7->10 =42
55 : 10->2 =110111 2->64 =t 64->7 =106 7->10 =55
57 : 10->2 =111001 2->64 =v 64->7 =111 7->10 =57
99 : 10->2 =1100011 2->64 =1Z 64->7 =201 7->10 =99
127: 10->2 =1111111 2->64 =1_ 64->7 =241 7->10 =127
DESCRIPTION
BaseCnv provides a few simple functions for converting between
arbitrary number bases. It is as fast as I currently know how to
make it (of course relying only on the lovely perl). If you
would rather utilize an object syntax for number-bass conversion,
please see Ken Williams' <ken@forum.swarthmore.edu> fine
Math::BaseCalc module.
2DO
better error checking
handle fractional parts? umm but I like using '.' as a b64 char =(
What else does BaseCnv need?
WHY?
The reason I created BaseCnv was that I needed a simple way to
convert quickly between the 3 number bases I use most (10, 16, &&
64). It turned out that it was trivial to handle any number bass
that could be represented as characters. High-bit ASCII proved
somewhat problemmatic but at least BaseCnv can convert between any
possible bass between 2 && 128 which is more than I originally
needed. I'm quite happy with it && employ b64() too much now =).
FUNCTIONS
cnv($numb[,$from[,$tobs]]) - Convert the number contained in $numb
from its current number bass ($from) into the result number bass
($tobs). If only $numb is provided, it will be converted to
hexadecimal (bass 16) if it only contains valid decimal digits or
it will be converted to decimal (bass 10) if it contains
hexadecimal digits or begins with '0x'. If only $numb && $from are
provided as parameters, cnv assumes that $numb is already in
decimal format && uses $from as the $tobs. The normal (&& most
clear) usage is to provide all 3 parameters.
cnv() is the only function that is exported from a normal
'use Math::BaseCnv;' command. Other functions can be imported
to local namespaces explicitly or with the following tags:
:all - every function described here
:hex - only dec() && hex()
:b64 - only b10() && b64() && cnv()
:dig - only dig() && diginit()
b10($b64n) - A shortcut to convert the number given as a parameter
($b64n) from bass 64 to decimal (bass 10).
b64($b10n) - A shortcut to convert the number given as a parameter
($b10n) from decimal (bass 10) to bass 64.
dec($b16n) - A shortcut to convert the number given as a parameter
($b16n) from hexadecimal (bass 16) to decimal (bass 10).
hex($b10n) - A shortcut to convert the number given as a parameter
($b10n) from decimal (bass 10) to hexadecimal (bass 16).
dig(\@newd) - Assign the new digit character list to be used in
place of the default one. dig() can also alternately accept a
string name matching one of the following predefined digit sets:
'bin' => ['0', '1']
'oct' => ['0'..'7']
'dec' => ['0'..'9']
'hex' => ['0'..'9', 'a'..'f']
'HEX' => ['0'..'9', 'A'..'F']
'b62' => ['0'..'9', 'a'..'z', 'A'..'Z']
'64' => ['A'..'Z', 'a'..'z', '0'..'9', '+', '/'] # MIME::Base64
'b64' => ['0'..'9', 'A'..'Z', 'a'..'z', '.', '_']
'128' => ['0'..'9', 'A'..'Z', 'a'..'z', '.', '_'... hi-bit chars
If no \@newd list or digit set name is provided as a parameter,
dig() returns the current character list. It's fine to have many
more characters in your current digit set than will be used with
your conversions (eg. using dig('128') works fine for any cnv()
call with $from && $tobs params less than or equal to 128).
An example of a \@newd parameter for a specified alternate digit
set for noval (bass 9) conversions is:
dig( [ qw( n a c h o z y u m ) ] );
diginit() - Resets the used digit list to the initial default order
of the predefined digit set: '128'.
NOTES
The perl builtin hex() function takes a hex string as a parameter &&
returns the decimal value (FromBass = 16, ToBass = 10) but this
notation seems counter-intuitive to me since the code implies that
a hex() function will turn your parameter into hexadecimal (ie. It
sounds like hex will hexify your parameter but it does not.) so
I've decided (maybe foolishly) to invert the notation for my
similar functions since it makes more sense to me this way && will
be easier to remember (I've had to lookup hex() in the Camel book
many times already which was part of the impetus for this module...
as well as the gut reaction that sprintf() is not a proper natural
inverse function for hex()).
This means that my b64() function takes a decimal number as a
parameter && returns the bass64 equivalent (FromBass = 10, ToBass =
64) && my b10() function takes a bass64 number (string) && returns
the decimal value (FromBass = 64, ToBass = 10). My hex() function
overloads perl's builtin version with this opposite behavior so my
dec() function behaves like perl's normal hex() function. I know
it's confusing && maybe bad form of me to do this but I like it
so much better this way that I'd rather go against the grain.
Please think of my dec() && hex() functions as meaning decify &&
hexify. Also the pronunciation of dec() is 'dess' (!'deck' as in
the inverse of 'ink' which -- && ++ have so improved upon). After
reading the informative perl module etiquette guidelines, I now
appreciate the need to export as little as is necessary by default.
So to be responsible, I have limited BaseCnv exporting to only
cnv() under normal circumstances. Please specify the other
functions you'd like to import into your namespace or use the tags
described above in the cnv() section like:
'use Math::BaseCnv qw(:all !:hex);'
Error checking is minimal at best so don't assume perfection...
yet =). Detectable errors return -1.
This module does not handle fractional number inputs because I like
using the dot (.) character as a standard bass64 digit since it
makes for clean filenames.
I hope you find BaseCnv useful. Please feel free to e-mail me any
suggestions || coding tips || notes of appreciation
("app-ree-see-ay-shun"). Thank you. TTFN.
LICENSE
All source code should be free! Code I have authority over is &&
shall be! Copyright (c) 2003, Pip Stuart. Copyleft: I license
this software under the GNU General Public License (version 2).
Please consult the Free Software Foundation (fsf.org) for important
information about your freedom.
AUTHOR
Pip Stuart <Pip@CPAN.org>