Number::Bytes::Human(3pm)

1Human(3)              User Contributed Perl Documentation             Human(3)
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NAME

6       Number::Bytes::Human - Convert byte count to human readable format
7

SYNOPSIS

9         use Number::Bytes::Human qw(format_bytes);
10         $size = format_bytes(0); # '0'
11         $size = format_bytes(2*1024); # '2.0K'
12
13         $size = format_bytes(1_234_890, bs => 1000); # '1.3M'
14         $size = format_bytes(1E9, bs => 1000); # '1.0G'
15
16         # the OO way
17         $human = Number::Bytes::Human->new(bs => 1000, si => 1);
18         $size = $human->format(1E7); # '10MB'
19         $human->set_options(zero => '-');
20         $size = $human->format(0); # '-'
21

DESCRIPTION

23       THIS IS ALPHA SOFTWARE: THE DOCUMENTATION AND THE CODE WILL SUFFER
24       CHANGES SOME DAY (THANKS, GOD!).
25
26       This module provides a formatter which turns byte counts to usual
27       readable format, like '2.0K', '3.1G', '100B'.  It was inspired in the
28       "-h" option of Unix utilities like "du", "df" and "ls" for "human-
29       readable" output.
30
31       From the FreeBSD man page of "df":
32       http://www.freebsd.org/cgi/man.cgi?query=df
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34         "Human-readable" output.  Use unit suffixes: Byte, Kilobyte,
35         Megabyte, Gigabyte, Terabyte and Petabyte in order to reduce the
36         number of digits to four or fewer using base 2 for sizes.
37
38         byte      B
39         kilobyte  K = 2**10 B = 1024 B
40         megabyte  M = 2**20 B = 1024 * 1024 B
41         gigabyte  G = 2**30 B = 1024 * 1024 * 1024 B
42         terabyte  T = 2**40 B = 1024 * 1024 * 1024 * 1024 B
43
44         petabyte  P = 2**50 B = 1024 * 1024 * 1024 * 1024 * 1024 B
45         exabyte   E = 2**60 B = 1024 * 1024 * 1024 * 1024 * 1024 * 1024 B
46         zettabyte Z = 2**70 B = 1024 * 1024 * 1024 * 1024 * 1024 * 1024 * 1024 B
47         yottabyte Y = 2**80 B = 1024 * 1024 * 1024 * 1024 * 1024 * 1024 * 1024 * 1024 B
48
49       I have found this link to be quite useful:
50
51         http://www.t1shopper.com/tools/calculate/
52
53       If you feel like a hard-drive manufacturer, you can start counting
54       bytes by powers of 1000 (instead of the generous 1024).  Just use "bs
55       => 1000".
56
57       But if you are a floppy disk manufacturer and want to start counting in
58       units of 1024000 (for your "1.44 MB" disks)?  Then use "bs =>
59       1_024_000".
60
61       If you feel like a purist academic, you can force the use of metric
62       prefixes according to the Dec 1998 standard by the IEC. Never mind the
63       units for base 1000 are "('B', 'kB', 'MB', 'GB', 'TB', 'PB', 'EB',
64       'ZB', 'YB')" and, even worse, the ones for base 1024 are "('B', 'KiB',
65       'MiB', 'GiB', 'TiB', 'PiB', 'EiB', 'ZiB', 'YiB')" with the horrible
66       names: bytes, kibibytes, mebibytes, etc.  All you have to do is to use
67       "si => 1". Ain't that beautiful the SI system? Read about it:
68
69         http://physics.nist.gov/cuu/Units/binary.html
70
71       You can try a pure Perl "ls -lh"-inspired command with the one-liner,
72       er, two-liner:
73
74         $ perl -MNumber::Bytes::Human=format_bytes \
75                -e 'printf "%5s %s\n", format_bytes(-s), $_ for @ARGV' *
76
77       Why to write such a module? Because if people can write such things in
78       C, it can be written much easier in Perl and then reused, refactored,
79       abused. And then, when it is much improved, some brave soul can port it
80       back to C (if only for the warm feeling of painful programming).
81
82   OBJECTS
83       An alternative to the functional style of this module is the OO
84       fashion. This is useful for avoiding the unnecessary parsing of the
85       arguments over and over if you have to format lots of numbers
86
87         for (@sizes) {
88           my $fmt_size = format_bytes($_, @args);
89           ...
90         }
91
92       versus
93
94         my $human = Number::Format::Bytes->new(@args);
95         for (@sizes) {
96           my $fmt_size = $human->format($_);
97           ...
98         }
99
100       for TODO [TODO] MAKE IT JUST A MATTER OF STYLE: memoize _parse_args()
101       $seed == undef
102
103   FUNCTIONS
104       format_bytes
105             $h_size = format_bytes($size, @options);
106
107           Turns a byte count (like 1230) to a readable format like '1.3K'.
108           You have a bunch of options to play with. See the section "OPTIONS"
109           to know the details.
110
111   METHODS
112       new
113             $h = Number::Bytes::Human->new(@options);
114
115           The constructor. For details on the arguments, see the section
116           "OPTIONS".
117
118       format
119             $h_size = $h->format($size);
120
121           Turns a byte count (like 1230) to a readable format like '1.3K'.
122           The statements
123
124             $h = Number::Bytes::Human->new(@options);
125             $h_size = $h->format($size);
126
127           are equivalent to "$h_size = format_bytes($size, @options)", with
128           only one pass for the option arguments.
129
130       set_options
131             $h->set_options(@options);
132
133           To alter the options of a "Number::Bytes::Human" object.  See
134           "OPTIONS".
135
136   OPTIONS
137       BASE
138             block | base | block_size | bs => 1000 | 1024 | 1024000
139             base_1024 | block_1024 | 1024 => 1
140             base_1000 | block_1000 | 1000 => 1
141
142           The base to be used: 1024 (default), 1000 or 1024000.
143
144           Any other value throws an exception.
145
146       SUFFIXES
147             suffixes => 1000 | 1024 | 1024000 | si_1000 | si_1024 | $arrayref
148
149           By default, the used suffixes stand for '', 'K', 'M', ...  for base
150           1024 and '', 'k', 'M', ... for base 1000 (which are indeed the
151           usual metric prefixes with implied unit as bytes, 'B'). For the
152           weird 1024000 base, suffixes are '', 'M', 'T', etc.
153
154       ZERO
155             zero => string | undef
156
157           The string 0 maps to ('0' by default). If "undef", the general case
158           is used.  The string may contain '%S' in which case the suffix for
159           byte is used.
160
161             format_bytes(0, zero => '-') => '-'
162
163       METRIC SYSTEM
164             si => 1
165
166       ROUND
167             round_function => $coderef
168             round_style => 'ceil' | 'floor'
169
170       TO_S
171       QUIET
172             quiet => 1
173
174           Suppresses the warnings emitted. Currently, the only case is when
175           the number is large than "$base**(@suffixes+1)".
176
177   EXPORT
178       It is alright to import "format_bytes", but nothing is exported by
179       default.
180

DIAGNOSTICS

182         "unknown round style '$style'";
183
184         "invalid base: $block (should be 1024, 1000 or 1024000)";
185
186         "round function ($args{round_function}) should be a code ref";
187
188         "suffixes ($args{suffixes}) should be 1000, 1024, 1024000 or an array ref";
189
190         "negative numbers are not allowed" (??)
191

TO DO

193       A function "parse_bytes"
194
195         parse_bytes($str, $options)
196
197       which transforms '1k' to 1000, '1K' to 1024, '1MB' to 1E6, '1M' to
198       1024*1024, etc. (like gnu du).
199
200         $str =~ /^\s*(\d*\.?\d*)\s*(\S+)/ # $num $suffix
201

BUGS

208       Please report bugs via CPAN RT
209       http://rt.cpan.org/NoAuth/Bugs.html?Dist=Number-Bytes-Human
210       <http://rt.cpan.org/NoAuth/Bugs.html?Dist=Number-Bytes-Human> or
211       mailto://bug-Number-Bytes-Human@rt.cpan.org <mailto://bug-Number-Bytes-
212       Human@rt.cpan.org>. I will not be able to close the bug as
213       BestPractical ignore my claims that I cannot log in, but I will answer
214       anyway.
215

AUTHOR

217       Adriano R. Ferreira, <ferreira@cpan.org>
218

COPYRIGHT AND LICENSE

220       Copyright (C) 2005-2007 by Adriano R. Ferreira
221
222       This library is free software; you can redistribute it and/or modify it
223       under the same terms as Perl itself.
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227perl v5.12.0                      2007-04-05                          Human(3)