[apple/libutil.git] / humanize_number.3

.\"	$NetBSD: humanize_number.3,v 1.4 2003/04/16 13:34:37 wiz Exp $
.\" $FreeBSD: src/lib/libutil/humanize_number.3,v 1.8 2005/04/10 12:15:25 delphij Exp $
.\"
.\" 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.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"        This product includes software developed by the NetBSD
.\"        Foundation, Inc. and its contributors.
.\" 4. Neither the name of The NetBSD Foundation nor the names of its
.\"    contributors may be used to endorse or promote products derived
.\"    from this software without specific prior written permission.
.\"
.\" 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 May 25, 2004
.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 buffer .
A space and then
.Fa suffix
is appended to the end.
The buffer pointed to by
.Fa buffer
must be at least
.Fa len
bytes long.
.Pp
If the formatted number (including
.Fa suffix )
would be too long to fit into
.Fa buffer ,
then divide
.Fa number
by 1024 until it will.
In this case, prefix
.Fa suffix
with the appropriate SI designator.
.Pp
The prefixes are:
.Bl -column "Prefix" "Description" "Multiplier" -offset indent
.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier"
.It Li k Ta No kilo Ta 1024
.It Li M Ta No mega Ta 1048576
.It Li G Ta No giga Ta 1073741824
.It Li T Ta No tera Ta 1099511627776
.It Li P Ta No peta Ta 1125899906842624
.It Li E Ta No exa 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 buffer .
To use a specific prefix, specify this as
.Fa scale
(multiplier = 1024 ^ scale).
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 digit.
.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.
.El
.Sh RETURN VALUES
The
.Fn humanize_number
function returns the number of characters stored in
.Fa buffer
(excluding the terminating
.Dv NUL )
upon success, or \-1 upon failure.
If
.Dv HN_GETSCALE
is specified, the prefix index number will be returned instead.
.Sh HISTORY
The
.Fn humanize_number
function first appeared in
.Nx 2.0 .
Commit	Line	Data
3f2457aa A	1	.\" $NetBSD: humanize_number.3,v 1.4 2003/04/16 13:34:37 wiz Exp $
	2	.\" $FreeBSD: src/lib/libutil/humanize_number.3,v 1.8 2005/04/10 12:15:25 delphij Exp $
	3	.\"
	4	.\" Copyright (c) 1999, 2002 The NetBSD Foundation, Inc.
	5	.\" All rights reserved.
	6	.\"
	7	.\" This code is derived from software contributed to The NetBSD Foundation
	8	.\" by Luke Mewburn and by Tomas Svensson.
	9	.\"
	10	.\" Redistribution and use in source and binary forms, with or without
	11	.\" modification, are permitted provided that the following conditions
	12	.\" are met:
	13	.\" 1. Redistributions of source code must retain the above copyright
	14	.\" notice, this list of conditions and the following disclaimer.
	15	.\" 2. Redistributions in binary form must reproduce the above copyright
	16	.\" notice, this list of conditions and the following disclaimer in the
	17	.\" documentation and/or other materials provided with the distribution.
	18	.\" 3. All advertising materials mentioning features or use of this software
	19	.\" must display the following acknowledgement:
	20	.\" This product includes software developed by the NetBSD
	21	.\" Foundation, Inc. and its contributors.
	22	.\" 4. Neither the name of The NetBSD Foundation nor the names of its
	23	.\" contributors may be used to endorse or promote products derived
	24	.\" from this software without specific prior written permission.
	25	.\"
	26	.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
	27	.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
	28	.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
	29	.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
	30	.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
	31	.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
	32	.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
	33	.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	34	.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
	35	.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
	36	.\" POSSIBILITY OF SUCH DAMAGE.
	37	.\"
	38	.Dd May 25, 2004
	39	.Dt HUMANIZE_NUMBER 3
	40	.Os
	41	.Sh NAME
	42	.Nm humanize_number
	43	.Nd format a number into a human readable form
	44	.Sh LIBRARY
	45	.Lb libutil
	46	.Sh SYNOPSIS
	47	.In libutil.h
	48	.Ft int
	49	.Fo humanize_number
	50	.Fa "char buf" "size_t len" "int64_t number" "const char suffix"
	51	.Fa "int scale" "int flags"
	52	.Fc
	53	.Sh DESCRIPTION
	54	The
	55	.Fn humanize_number
	56	function formats the signed 64-bit quantity given in
	57	.Fa number
	58	into
	59	.Fa buffer .
	60	A space and then
	61	.Fa suffix
	62	is appended to the end.
	63	The buffer pointed to by
	64	.Fa buffer
65	must be at least
66	.Fa len
67	bytes long.
68	.Pp
69	If the formatted number (including
70	.Fa suffix )
71	would be too long to fit into
72	.Fa buffer ,
73	then divide
74	.Fa number
75	by 1024 until it will.
76	In this case, prefix
77	.Fa suffix
78	with the appropriate SI designator.
79	.Pp
80	The prefixes are:
81	.Bl -column "Prefix" "Description" "Multiplier" -offset indent
82	.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier"
83	.It Li k Ta No kilo Ta 1024
84	.It Li M Ta No mega Ta 1048576
85	.It Li G Ta No giga Ta 1073741824
86	.It Li T Ta No tera Ta 1099511627776
87	.It Li P Ta No peta Ta 1125899906842624
88	.It Li E Ta No exa Ta 1152921504606846976
89	.El
90	.Pp
91	The
92	.Fa len
93	argument must be at least 4 plus the length of
94	.Fa suffix ,
95	in order to ensure a useful result is generated into
96	.Fa buffer .
97	To use a specific prefix, specify this as
98	.Fa scale
99	(multiplier = 1024 ^ scale).
100	This cannot be combined with any of the
101	.Fa scale
102	flags below.
103	.Pp
104	The following flags may be passed in
105	.Fa scale :
106	.Bl -tag -width ".Dv HN_DIVISOR_1000" -offset indent
107	.It Dv HN_AUTOSCALE
108	Format the buffer using the lowest multiplier possible.
109	.It Dv HN_GETSCALE
110	Return the prefix index number (the number of times
111	.Fa number
112	must be divided to fit) instead of formatting it to the buffer.
113	.El
114	.Pp
115	The following flags may be passed in
116	.Fa flags :
117	.Bl -tag -width ".Dv HN_DIVISOR_1000" -offset indent
118	.It Dv HN_DECIMAL
119	If the final result is less than 10, display it using one digit.
120	.It Dv HN_NOSPACE
121	Do not put a space between
122	.Fa number
123	and the prefix.
124	.It Dv HN_B
125	Use
126	.Ql B
127	(bytes) as prefix if the original result does not have a prefix.
128	.It Dv HN_DIVISOR_1000
129	Divide
130	.Fa number
131	with 1000 instead of 1024.
132	.El
133	.Sh RETURN VALUES
134	The
135	.Fn humanize_number
136	function returns the number of characters stored in
137	.Fa buffer
138	(excluding the terminating
139	.Dv NUL )
140	upon success, or \-1 upon failure.
141	If
142	.Dv HN_GETSCALE
143	is specified, the prefix index number will be returned instead.
144	.Sh HISTORY
145	The
146	.Fn humanize_number
147	function first appeared in
148	.Nx 2.0 .