Human(3) User Contributed Perl Documentation Human(3)NAMENumber::Bytes::Human - Convert byte count to human readable format
SYNOPSIS
use Number::Bytes::Humanqw(format_bytes);
$size = format_bytes(0); # '0'
$size = format_bytes(2*1024); # '2.0K'
$size = format_bytes(1_234_890, bs => 1000); # '1.3M'
$size = format_bytes(1E9, bs => 1000); # '1.0G'
# the OO way
$human = Number::Bytes::Human->new(bs => 1000, si => 1);
$size = $human->format(1E7); # '10MB'
$human->set_options(zero => '-');
$size = $human->format(0); # '-'
DESCRIPTION
THIS IS ALPHA SOFTWARE: THE DOCUMENTATION AND THE CODE WILL SUFFER
CHANGES SOME DAY (THANKS, GOD!).
This module provides a formatter which turns byte counts to usual
readable format, like '2.0K', '3.1G', '100B'. It was inspired in the
"-h" option of Unix utilities like "du", "df" and "ls" for "human-
readable" output.
From the FreeBSD man page of "df":
http://www.freebsd.org/cgi/man.cgi?query=df
"Human-readable" output. Use unit suffixes: Byte, Kilobyte,
Megabyte, Gigabyte, Terabyte and Petabyte in order to reduce the
number of digits to four or fewer using base 2 for sizes.
byte B
kilobyte K = 2**10 B = 1024 B
megabyte M = 2**20 B = 1024 * 1024 B
gigabyte G = 2**30 B = 1024 * 1024 * 1024 B
terabyte T = 2**40 B = 1024 * 1024 * 1024 * 1024 B
petabyte P = 2**50 B = 1024 * 1024 * 1024 * 1024 * 1024 B
exabyte E = 2**60 B = 1024 * 1024 * 1024 * 1024 * 1024 * 1024 B
zettabyte Z = 2**70 B = 1024 * 1024 * 1024 * 1024 * 1024 * 1024 * 1024 B
yottabyte Y = 2**80 B = 1024 * 1024 * 1024 * 1024 * 1024 * 1024 * 1024 * 1024 B
I have found this link to be quite useful:
http://www.t1shopper.com/tools/calculate/
If you feel like a hard-drive manufacturer, you can start counting
bytes by powers of 1000 (instead of the generous 1024). Just use "bs
=> 1000".
But if you are a floppy disk manufacturer and want to start counting in
units of 1024000 (for your "1.44 MB" disks)? Then use "bs =>
1_024_000".
If you feel like a purist academic, you can force the use of metric
prefixes according to the Dec 1998 standard by the IEC. Never mind the
units for base 1000 are "('B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB',
'ZB', 'YB')" and, even worse, the ones for base 1024 are "('B', 'KiB',
'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB')" with the horrible
names: bytes, kibibytes, mebibytes, etc. All you have to do is to use
"si => 1". Ain't that beautiful the SI system? Read about it:
http://physics.nist.gov/cuu/Units/binary.html
You can try a pure Perl "ls -lh"-inspired command with the one-liner,
er, two-liner:
$ perl -MNumber::Bytes::Human=format_bytes \
-e 'printf "%5s %s\n", format_bytes(-s), $_ for @ARGV' *
Why to write such a module? Because if people can write such things in
C, it can be written much easier in Perl and then reused, refactored,
abused. And then, when it is much improved, some brave soul can port it
back to C (if only for the warm feeling of painful programming).
OBJECTS
An alternative to the functional style of this module is the OO
fashion. This is useful for avoiding the unnecessary parsing of the
arguments over and over if you have to format lots of numbers
for (@sizes) {
my $fmt_size = format_bytes($_, @args);
...
}
versus
my $human = Number::Format::Bytes->new(@args);
for (@sizes) {
my $fmt_size = $human->format($_);
...
}
for TODO [TODO] MAKE IT JUST A MATTER OF STYLE: memoize _parse_args()
$seed == undef
FUNCTIONS
format_bytes
$h_size = format_bytes($size, @options);
Turns a byte count (like 1230) to a readable format like '1.3K'.
You have a bunch of options to play with. See the section "OPTIONS"
to know the details.
METHODS
new
$h = Number::Bytes::Human->new(@options);
The constructor. For details on the arguments, see the section
"OPTIONS".
format
$h_size = $h->format($size);
Turns a byte count (like 1230) to a readable format like '1.3K'.
The statements
$h = Number::Bytes::Human->new(@options);
$h_size = $h->format($size);
are equivalent to "$h_size = format_bytes($size, @options)", with
only one pass for the option arguments.
set_options
$h->set_options(@options);
To alter the options of a "Number::Bytes::Human" object. See
"OPTIONS".
OPTIONS
BASE
block | base | block_size | bs => 1000 | 1024 | 1024000
base_1024 | block_1024 | 1024 => 1
base_1000 | block_1000 | 1000 => 1
The base to be used: 1024 (default), 1000 or 1024000.
Any other value throws an exception.
SUFFIXES
suffixes => 1000 | 1024 | 1024000 | si_1000 | si_1024 | $arrayref
By default, the used suffixes stand for '', 'K', 'M', ... for base
1024 and '', 'k', 'M', ... for base 1000 (which are indeed the
usual metric prefixes with implied unit as bytes, 'B'). For the
weird 1024000 base, suffixes are '', 'M', 'T', etc.
ZERO
zero => string | undef
The string 0 maps to ('0' by default). If "undef", the general case
is used. The string may contain '%S' in which case the suffix for
byte is used.
format_bytes(0, zero => '-') => '-'
METRIC SYSTEM
si => 1
ROUND
round_function => $coderef
round_style => 'ceil' | 'floor'
TO_S
QUIET
quiet => 1
Suppresses the warnings emitted. Currently, the only case is when
the number is large than "$base**(@suffixes+1)".
EXPORT
It is alright to import "format_bytes", but nothing is exported by
default.
DIAGNOSTICS
"unknown round style '$style'";
"invalid base: $block (should be 1024, 1000 or 1024000)";
"round function ($args{round_function}) should be a code ref";
"suffixes ($args{suffixes}) should be 1000, 1024, 1024000 or an array ref";
"negative numbers are not allowed" (??)
TO DO
A function "parse_bytes"
parse_bytes($str, $options)
which transforms '1k' to 1000, '1K' to 1024, '1MB' to 1E6, '1M' to
1024*1024, etc. (like gnu du).
$str =~ /^\s*(\d*\.?\d*)\s*(\S+)/ # $num $suffix
SEE ALSO
lib/human.c and lib/human.h in GNU coreutils.
The "_convert()" solution by COG in Filesys::DiskUsage.
BUGS
Please report bugs via CPAN RT
http://rt.cpan.org/NoAuth/Bugs.html?Dist=Number-Bytes-Human
<http://rt.cpan.org/NoAuth/Bugs.html?Dist=Number-Bytes-Human> or
mailto://bug-Number-Bytes-Human@rt.cpan.org <mailto://bug-Number-Bytes-
Human@rt.cpan.org>. I will not be able to close the bug as
BestPractical ignore my claims that I cannot log in, but I will answer
anyway.
AUTHOR
Adriano R. Ferreira, <ferreira@cpan.org>
COPYRIGHT AND LICENSE
Copyright (C) 2005-2007 by Adriano R. Ferreira
This library is free software; you can redistribute it and/or modify it
under the same terms as Perl itself.
perl v5.14.0 2007-04-05 Human(3)