1.\" $NetBSD: humanize_number.3,v 1.4 2003/04/16 13:34:37 wiz Exp $ 2.\" $FreeBSD: head/lib/libutil/humanize_number.3 256130 2013-10-07 22:22:57Z jmg $ 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 October 7, 2013 32.Dt HUMANIZE_NUMBER 3 33.Os 34.Sh NAME 35.Nm dehumanize_number , 36.Nm humanize_number 37.Nd format a number into a human readable form and vice versa 38.Sh LIBRARY 39.Lb libutil 40.Sh SYNOPSIS 41.In sys/types.h 42.In libutil.h 43.Ft int 44.Fn dehumanize_number "const char *str" "int64_t *result" 45.Ft int 46.Fo humanize_number 47.Fa "char *buf" "size_t len" "int64_t number" "const char *suffix" 48.Fa "int scale" "int flags" 49.Fc 50.Sh DESCRIPTION 51The 52.Fn humanize_number 53function formats the signed 64-bit quantity given in 54.Fa number 55into 56.Fa buf . 57A space and then 58.Fa suffix 59is appended to the end. 60The buffer pointed to by 61.Fa buf 62must be at least 63.Fa len 64bytes long. 65.Pp 66If the formatted number (including 67.Fa suffix ) 68would be too long to fit into 69.Fa buf , 70then divide 71.Fa number 72by 1024 until it will. 73In this case, prefix 74.Fa suffix 75with the appropriate SI designator. 76The 77.Fn humanize_number 78function follows the traditional computer science conventions by 79default, rather than the IEE/IEC (and now also SI) power of two 80convention or the power of ten notion. 81This behaviour however can be altered by specifying the 82.Dv HN_DIVISOR_1000 83and 84.Dv HN_IEC_PREFIXES 85flags. 86.Pp 87The traditional 88.Pq default 89prefixes are: 90.Bl -column "Prefix" "Description" "1000000000000000000" -offset indent 91.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier" Ta Sy "Multiplier 1000x" 92.It Li (note) Ta No kilo Ta 1024 Ta 1000 93.It Li M Ta No mega Ta 1048576 Ta 1000000 94.It Li G Ta No giga Ta 1073741824 Ta 1000000000 95.It Li T Ta No tera Ta 1099511627776 Ta 1000000000000 96.It Li P Ta No peta Ta 1125899906842624 Ta 1000000000000000 97.It Li E Ta No exa Ta 1152921504606846976 Ta 1000000000000000000 98.El 99.Pp 100Note: 101An uppercase K indicates a power of two, a lowercase k a power of ten. 102.Pp 103The IEE/IEC (and now also SI) power of two prefixes are: 104.Bl -column "Prefix" "Description" "1000000000000000000" -offset indent 105.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier" 106.It Li Ki Ta No kibi Ta 1024 107.It Li Mi Ta No mebi Ta 1048576 108.It Li Gi Ta No gibi Ta 1073741824 109.It Li Ti Ta No tebi Ta 1099511627776 110.It Li Pi Ta No pebi Ta 1125899906842624 111.It Li Ei Ta No exbi Ta 1152921504606846976 112.El 113.Pp 114The 115.Fa len 116argument must be at least 4 plus the length of 117.Fa suffix , 118in order to ensure a useful result is generated into 119.Fa buf . 120To use a specific prefix, specify this as 121.Fa scale 122.Po multiplier = 1024 ^ scale; 123when 124.Dv HN_DIVISOR_1000 125is specified, 126multiplier = 1000 ^ scale 127.Pc . 128This cannot be combined with any of the 129.Fa scale 130flags below. 131.Pp 132The following flags may be passed in 133.Fa scale : 134.Bl -tag -width ".Dv HN_DIVISOR_1000" -offset indent 135.It Dv HN_AUTOSCALE 136Format the buffer using the lowest multiplier possible. 137.It Dv HN_GETSCALE 138Return the prefix index number (the number of times 139.Fa number 140must be divided to fit) instead of formatting it to the buffer. 141.El 142.Pp 143The following flags may be passed in 144.Fa flags : 145.Bl -tag -width ".Dv HN_DIVISOR_1000" -offset indent 146.It Dv HN_DECIMAL 147If the final result is less than 10, display it using one decimal place. 148.It Dv HN_NOSPACE 149Do not put a space between 150.Fa number 151and the prefix. 152.It Dv HN_B 153Use 154.Ql B 155(bytes) as prefix if the original result does not have a prefix. 156.It Dv HN_DIVISOR_1000 157Divide 158.Fa number 159with 1000 instead of 1024. 160.It Dv HN_IEC_PREFIXES 161Use the IEE/IEC notion of prefixes (Ki, Mi, Gi...). 162This flag has no effect when 163.Dv HN_DIVISOR_1000 164is also specified. 165.El 166.Pp 167The 168.Fn dehumanize_number 169function parses the string representing an integral value given in 170.Fa str 171and stores the numerical value in the integer pointed to by 172.Fa result . 173The provided string may hold one of the suffixes, which will be interpreted 174and used to scale up its accompanying numerical value. 175.Sh RETURN VALUES 176Upon success, the 177.Fn humanize_number 178function returns the number of characters that would have been stored in 179.Fa buf 180(excluding the terminating 181.Dv NUL ) 182if 183.Fa buf 184was large enough, or \-1 upon failure. 185Even upon failure, the contents of 186.Fa buf 187may be modified. 188If 189.Dv HN_GETSCALE 190is specified, the prefix index number will be returned instead. 191.Pp 192The 193.Fn dehumanize_number 194function returns 0 if the string was parsed correctly. 195A \-1 is returned to indicate failure and an error code is stored in 196.Va errno . 197.Sh ERRORS 198The 199.Fn dehumanize_number 200function will fail and no number will be stored in 201.Fa result 202if: 203.Bl -tag -width Er 204.It Bq Er EINVAL 205The string in 206.Fa str 207was empty or carried an unknown suffix. 208.It Bq Er ERANGE 209The string in 210.Fa str 211represented a number that does not fit in 212.Fa result . 213.El 214.Sh STANDARDS 215The 216.Dv HN_DIVISOR_1000 217and 218.Dv HN_IEC_PREFIXES 219flags 220conform to 221.Tn ISO/IEC 222Std\~80000-13:2008 223and 224.Tn IEEE 225Std\~1541-2002. 226.Sh HISTORY 227The 228.Fn humanize_number 229function first appeared in 230.Nx 2.0 231and then in 232.Fx 5.3 . 233The 234.Dv HN_IEC_PREFIXES 235flag was introduced in 236.Fx 9.0 . 237