1.\" $NetBSD: humanize_number.3,v 1.4 2003/04/16 13:34:37 wiz Exp $ 2.\" $FreeBSD$ 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.\" 19.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 20.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 21.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 22.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 23.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 24.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 25.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 26.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 27.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 28.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 29.\" POSSIBILITY OF SUCH DAMAGE. 30.\" 31.Dd Apr 12, 2011 32.Dt HUMANIZE_NUMBER 3 33.Os 34.Sh NAME 35.Nm humanize_number 36.Nd format a number into a human readable form 37.Sh LIBRARY 38.Lb libutil 39.Sh SYNOPSIS 40.In libutil.h 41.Ft int 42.Fo humanize_number 43.Fa "char *buf" "size_t len" "int64_t number" "const char *suffix" 44.Fa "int scale" "int flags" 45.Fc 46.Sh DESCRIPTION 47The 48.Fn humanize_number 49function formats the signed 64-bit quantity given in 50.Fa number 51into 52.Fa buf . 53A space and then 54.Fa suffix 55is appended to the end. 56The buffer pointed to by 57.Fa buf 58must be at least 59.Fa len 60bytes long. 61.Pp 62If the formatted number (including 63.Fa suffix ) 64would be too long to fit into 65.Fa buf , 66then divide 67.Fa number 68by 1024 until it will. 69In this case, prefix 70.Fa suffix 71with the appropriate designator. 72The 73.Fn humanize_number 74function follows the traditional computer science conventions by 75default, rather than the IEE/IEC (and now also SI) power of two 76convention or the power of ten notion. 77This behaviour however can be altered by specifying the 78.Dv HN_DIVISOR_1000 79and 80.Dv HN_IEC_PREFIXES 81flags. 82.Pp 83The traditional 84.Pq default 85prefixes are: 86.Bl -column "Prefix" "Description" "1000000000000000000" -offset indent 87.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier" Ta Sy "Multiplier 1000x" 88.It Li (note) Ta No kilo Ta 1024 Ta 1000 89.It Li M Ta No mega Ta 1048576 Ta 1000000 90.It Li G Ta No giga Ta 1073741824 Ta 1000000000 91.It Li T Ta No tera Ta 1099511627776 Ta 1000000000000 92.It Li P Ta No peta Ta 1125899906842624 Ta 1000000000000000 93.It Li E Ta No exa Ta 1152921504606846976 Ta 1000000000000000000 94.El 95.Pp 96Note: 97An uppercase K indicates a power of two, a lowercase k a power of ten. 98.Pp 99The IEE/IEC (and now also SI) power of two prefixes are: 100.Bl -column "Prefix" "Description" "1000000000000000000" -offset indent 101.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier" 102.It Li Ki Ta No kibi Ta 1024 103.It Li Mi Ta No mebi Ta 1048576 104.It Li Gi Ta No gibi Ta 1073741824 105.It Li Ti Ta No tebi Ta 1099511627776 106.It Li Pi Ta No pebi Ta 1125899906842624 107.It Li Ei Ta No exbi Ta 1152921504606846976 108.El 109.Pp 110The 111.Fa len 112argument must be at least 4 plus the length of 113.Fa suffix , 114in order to ensure a useful result is generated into 115.Fa buf . 116To use a specific prefix, specify this as 117.Fa scale 118.Po multiplier = 1024 ^ scale; 119when 120.Dv HN_DIVISOR_1000 121is specified, 122multiplier = 1000 ^ scale 123.Pc . 124This cannot be combined with any of the 125.Fa scale 126flags below. 127.Pp 128The following flags may be passed in 129.Fa scale : 130.Bl -tag -width ".Dv HN_DIVISOR_1000" -offset indent 131.It Dv HN_AUTOSCALE 132Format the buffer using the lowest multiplier possible. 133.It Dv HN_GETSCALE 134Return the prefix index number (the number of times 135.Fa number 136must be divided to fit) instead of formatting it to the buffer. 137.El 138.Pp 139The following flags may be passed in 140.Fa flags : 141.Bl -tag -width ".Dv HN_DIVISOR_1000" -offset indent 142.It Dv HN_DECIMAL 143If the final result is less than 10, display it using one digit. 144.It Dv HN_NOSPACE 145Do not put a space between 146.Fa number 147and the prefix. 148.It Dv HN_B 149Use 150.Ql B 151(bytes) as prefix if the original result does not have a prefix. 152.It Dv HN_DIVISOR_1000 153Divide 154.Fa number 155with 1000 instead of 1024. 156.It Dv HN_IEC_PREFIXES 157Use the IEE/IEC notion of prefixes (Ki, Mi, Gi...). 158This flag has no effect when 159.Dv HN_DIVISOR_1000 160is also specified. 161.El 162.Sh RETURN VALUES 163The 164.Fn humanize_number 165function returns the number of characters stored in 166.Fa buf 167(excluding the terminating 168.Dv NUL ) 169upon success, or \-1 upon failure. 170If 171.Dv HN_GETSCALE 172is specified, the prefix index number will be returned instead. 173.Sh SEE ALSO 174.Xr expand_number 3 175.Sh STANDARDS 176The 177.Dv HN_DIVISOR_1000 178and 179.Dv HN_IEC_PREFIXES 180flags 181conform to 182.Tn ISO/IEC 183Std\~80000-13:2008 184and 185.Tn IEEE 186Std\~1541-2002. 187.Sh HISTORY 188The 189.Fn humanize_number 190function first appeared in 191.Nx 2.0 192and then in 193.Fx 5.3 . 194The 195.Dv HN_IEC_PREFIXES 196flag was introduced in 197.Fx 9.0 . 198