ec9fa283ad
Since so many programs don't check return value, always NUL terminate the buf... fix rounding when using base 1024 (the bug that started it all)... add a set of test cases so we can make sure that things don't break in the future... Thanks to Clifton Royston for testing and the test program... Approved by: re (hrs, glebius) MFC after: 1 week
203 lines
5.5 KiB
Groff
203 lines
5.5 KiB
Groff
.\" $NetBSD: humanize_number.3,v 1.4 2003/04/16 13:34:37 wiz Exp $
|
|
.\" $FreeBSD$
|
|
.\"
|
|
.\" Copyright (c) 1999, 2002 The NetBSD Foundation, Inc.
|
|
.\" All rights reserved.
|
|
.\"
|
|
.\" This code is derived from software contributed to The NetBSD Foundation
|
|
.\" by Luke Mewburn and by Tomas Svensson.
|
|
.\"
|
|
.\" Redistribution and use in source and binary forms, with or without
|
|
.\" modification, are permitted provided that the following conditions
|
|
.\" are met:
|
|
.\" 1. Redistributions of source code must retain the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer.
|
|
.\" 2. Redistributions in binary form must reproduce the above copyright
|
|
.\" notice, this list of conditions and the following disclaimer in the
|
|
.\" documentation and/or other materials provided with the distribution.
|
|
.\"
|
|
.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
|
|
.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
|
|
.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
|
|
.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
|
|
.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
|
|
.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
|
|
.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
|
|
.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
|
|
.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
|
|
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
|
|
.\" POSSIBILITY OF SUCH DAMAGE.
|
|
.\"
|
|
.Dd October 7, 2013
|
|
.Dt HUMANIZE_NUMBER 3
|
|
.Os
|
|
.Sh NAME
|
|
.Nm humanize_number
|
|
.Nd format a number into a human readable form
|
|
.Sh LIBRARY
|
|
.Lb libutil
|
|
.Sh SYNOPSIS
|
|
.In libutil.h
|
|
.Ft int
|
|
.Fo humanize_number
|
|
.Fa "char *buf" "size_t len" "int64_t number" "const char *suffix"
|
|
.Fa "int scale" "int flags"
|
|
.Fc
|
|
.Sh DESCRIPTION
|
|
The
|
|
.Fn humanize_number
|
|
function formats the signed 64-bit quantity given in
|
|
.Fa number
|
|
into
|
|
.Fa buf .
|
|
A space and then
|
|
.Fa suffix
|
|
is appended to the end.
|
|
The buffer pointed to by
|
|
.Fa buf
|
|
must be at least
|
|
.Fa len
|
|
bytes long.
|
|
.Pp
|
|
If the formatted number (including
|
|
.Fa suffix )
|
|
would be too long to fit into
|
|
.Fa buf ,
|
|
then divide
|
|
.Fa number
|
|
by 1024 until it will.
|
|
In this case, prefix
|
|
.Fa suffix
|
|
with the appropriate designator.
|
|
The
|
|
.Fn humanize_number
|
|
function follows the traditional computer science conventions by
|
|
default, rather than the IEE/IEC (and now also SI) power of two
|
|
convention or the power of ten notion.
|
|
This behaviour however can be altered by specifying the
|
|
.Dv HN_DIVISOR_1000
|
|
and
|
|
.Dv HN_IEC_PREFIXES
|
|
flags.
|
|
.Pp
|
|
The traditional
|
|
.Pq default
|
|
prefixes are:
|
|
.Bl -column "Prefix" "Description" "1000000000000000000" -offset indent
|
|
.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier" Ta Sy "Multiplier 1000x"
|
|
.It Li (note) Ta No kilo Ta 1024 Ta 1000
|
|
.It Li M Ta No mega Ta 1048576 Ta 1000000
|
|
.It Li G Ta No giga Ta 1073741824 Ta 1000000000
|
|
.It Li T Ta No tera Ta 1099511627776 Ta 1000000000000
|
|
.It Li P Ta No peta Ta 1125899906842624 Ta 1000000000000000
|
|
.It Li E Ta No exa Ta 1152921504606846976 Ta 1000000000000000000
|
|
.El
|
|
.Pp
|
|
Note:
|
|
An uppercase K indicates a power of two, a lowercase k a power of ten.
|
|
.Pp
|
|
The IEE/IEC (and now also SI) power of two prefixes are:
|
|
.Bl -column "Prefix" "Description" "1000000000000000000" -offset indent
|
|
.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier"
|
|
.It Li Ki Ta No kibi Ta 1024
|
|
.It Li Mi Ta No mebi Ta 1048576
|
|
.It Li Gi Ta No gibi Ta 1073741824
|
|
.It Li Ti Ta No tebi Ta 1099511627776
|
|
.It Li Pi Ta No pebi Ta 1125899906842624
|
|
.It Li Ei Ta No exbi Ta 1152921504606846976
|
|
.El
|
|
.Pp
|
|
The
|
|
.Fa len
|
|
argument must be at least 4 plus the length of
|
|
.Fa suffix ,
|
|
in order to ensure a useful result is generated into
|
|
.Fa buf .
|
|
To use a specific prefix, specify this as
|
|
.Fa scale
|
|
.Po multiplier = 1024 ^ scale;
|
|
when
|
|
.Dv HN_DIVISOR_1000
|
|
is specified,
|
|
multiplier = 1000 ^ scale
|
|
.Pc .
|
|
This cannot be combined with any of the
|
|
.Fa scale
|
|
flags below.
|
|
.Pp
|
|
The following flags may be passed in
|
|
.Fa scale :
|
|
.Bl -tag -width ".Dv HN_DIVISOR_1000" -offset indent
|
|
.It Dv HN_AUTOSCALE
|
|
Format the buffer using the lowest multiplier possible.
|
|
.It Dv HN_GETSCALE
|
|
Return the prefix index number (the number of times
|
|
.Fa number
|
|
must be divided to fit) instead of formatting it to the buffer.
|
|
.El
|
|
.Pp
|
|
The following flags may be passed in
|
|
.Fa flags :
|
|
.Bl -tag -width ".Dv HN_DIVISOR_1000" -offset indent
|
|
.It Dv HN_DECIMAL
|
|
If the final result is less than 10, display it using one decimal place.
|
|
.It Dv HN_NOSPACE
|
|
Do not put a space between
|
|
.Fa number
|
|
and the prefix.
|
|
.It Dv HN_B
|
|
Use
|
|
.Ql B
|
|
(bytes) as prefix if the original result does not have a prefix.
|
|
.It Dv HN_DIVISOR_1000
|
|
Divide
|
|
.Fa number
|
|
with 1000 instead of 1024.
|
|
.It Dv HN_IEC_PREFIXES
|
|
Use the IEE/IEC notion of prefixes (Ki, Mi, Gi...).
|
|
This flag has no effect when
|
|
.Dv HN_DIVISOR_1000
|
|
is also specified.
|
|
.El
|
|
.Sh RETURN VALUES
|
|
Upon success, the
|
|
.Nm
|
|
function returns the number of characters that would have been stored in
|
|
.Fa buf
|
|
(excluding the terminating
|
|
.Dv NUL )
|
|
if
|
|
.Fa buf
|
|
was large enough, or \-1 upon failure.
|
|
Even upon failure, the contents of
|
|
.Fa buf
|
|
may be modified.
|
|
If
|
|
.Dv HN_GETSCALE
|
|
is specified, the prefix index number will be returned instead.
|
|
.Sh SEE ALSO
|
|
.Xr expand_number 3
|
|
.Sh STANDARDS
|
|
The
|
|
.Dv HN_DIVISOR_1000
|
|
and
|
|
.Dv HN_IEC_PREFIXES
|
|
flags
|
|
conform to
|
|
.Tn ISO/IEC
|
|
Std\~80000-13:2008
|
|
and
|
|
.Tn IEEE
|
|
Std\~1541-2002.
|
|
.Sh HISTORY
|
|
The
|
|
.Fn humanize_number
|
|
function first appeared in
|
|
.Nx 2.0
|
|
and then in
|
|
.Fx 5.3 .
|
|
The
|
|
.Dv HN_IEC_PREFIXES
|
|
flag was introduced in
|
|
.Fx 9.0 .
|