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 December 30, 2016 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_FRACTIONAL 147Display up to two additional fractional digits if they would fit, unless 148the value was so small (i.e. less than 1000 or less than 1024) that it 149wouldn't make sense. 150.It Dv HN_DECIMAL 151If the final result is less than 10, display it using one decimal place. 152.It Dv HN_NOSPACE 153Do not put a space between 154.Fa number 155and the prefix. 156.It Dv HN_B 157Use 158.Ql B 159(bytes) as prefix if the original result does not have a prefix. 160.It Dv HN_DIVISOR_1000 161Divide 162.Fa number 163with 1000 instead of 1024. 164.It Dv HN_IEC_PREFIXES 165Use the IEE/IEC notion of prefixes (Ki, Mi, Gi...). 166This flag has no effect when 167.Dv HN_DIVISOR_1000 168is also specified. 169.El 170.Pp 171The 172.Fn dehumanize_number 173function parses the string representing an integral value given in 174.Fa str 175and stores the numerical value in the integer pointed to by 176.Fa result . 177The provided string may hold one of the suffixes, which will be interpreted 178and used to scale up its accompanying numerical value. 179.Sh RETURN VALUES 180Upon success, the 181.Fn humanize_number 182function returns the number of characters that would have been stored in 183.Fa buf 184(excluding the terminating 185.Dv NUL ) 186if 187.Fa buf 188was large enough, or \-1 upon failure. 189Even upon failure, the contents of 190.Fa buf 191may be modified. 192If 193.Dv HN_GETSCALE 194is specified, the prefix index number will be returned instead. 195.Pp 196The 197.Fn dehumanize_number 198function returns 0 if the string was parsed correctly. 199A \-1 is returned to indicate failure and an error code is stored in 200.Va errno . 201.Sh ERRORS 202The 203.Fn dehumanize_number 204function will fail and no number will be stored in 205.Fa result 206if: 207.Bl -tag -width Er 208.It Bq Er EINVAL 209The string in 210.Fa str 211was empty or carried an unknown suffix. 212.It Bq Er ERANGE 213The string in 214.Fa str 215represented a number that does not fit in 216.Fa result . 217.El 218.Sh STANDARDS 219The 220.Dv HN_DIVISOR_1000 221and 222.Dv HN_IEC_PREFIXES 223flags 224conform to 225.Tn ISO/IEC 226Std\~80000-13:2008 227and 228.Tn IEEE 229Std\~1541-2002. 230.Sh HISTORY 231The 232.Fn humanize_number 233function first appeared in 234.Nx 2.0 235and then in 236.Fx 5.3 . 237The 238.Dv HN_IEC_PREFIXES 239flag was introduced in 240.Fx 9.0 . 241