1.\" $NetBSD: humanize_number.3,v 1.13 2019/03/12 22:21:53 wiz Exp $ 2.\" 3.\" Copyright (c) 1999, 2002, 2008 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Luke Mewburn and by Tomas Svensson. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 19.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 20.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 21.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 22.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 23.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 24.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 25.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 26.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 27.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 28.\" POSSIBILITY OF SUCH DAMAGE. 29.\" 30.Dd March 11, 2019 31.Dt HUMANIZE_NUMBER 3 32.Os 33.Sh NAME 34.Nm dehumanize_number , 35.Nm humanize_number 36.Nd format a number into a human readable form and vice versa 37.Sh SYNOPSIS 38.In stdlib.h 39.Ft int 40.Fn dehumanize_number "const char *str" "int64_t *result" 41.Ft int 42.Fn humanize_number "char *buffer" "size_t len" "int64_t number" "const char *suffix" "int scale" "int flags" 43.Sh DESCRIPTION 44The 45.Fn humanize_number 46function formats the signed 64 bit quantity given in 47.Fa number 48into 49.Fa buffer . 50A space and then the 51.Fa suffix 52.Pq "if not null" 53is appended to the end. 54.Fa len 55gives the size of the 56.Fa buffer . 57.Pp 58If the formatted number (including 59.Fa suffix ) 60would be too long to fit into 61.Fa buffer , 62then repeatedly divide 63.Fa number 64by 1024 until it will fit. 65In this case, prefix 66.Fa suffix 67with the appropriate SI designator. 68.Pp 69The prefixes are: 70.Bl -column "Prefix" "Description" "Multiplier" -offset indent 71.It Sy "Prefix" Ta Sy "Description" Ta Sy "Multiplier" 72.It k kilo 1024 73.It M mega 1048576 74.It G giga 1073741824 75.It T tera 1099511627776 76.It P peta 1125899906842624 77.It E exa 1152921504606846976 78.El 79.Pp 80.Fa len 81must be at least 4 plus the length of 82.Fa suffix , 83in order to ensure a useful result is generated into 84.Fa buffer . 85To use a specific prefix, specify this as 86.Fa scale 87(Multiplier = 1024 ^ scale). 88The 89.Fa scale 90must be at least 0 and no more than 6. 91.Pp 92Alternatively, one of the following special values may be given as 93.Pa scale : 94.Bl -tag -width Dv -offset indent 95.It Dv HN_AUTOSCALE 96Format the buffer using the lowest multiplier possible. 97.It Dv HN_GETSCALE 98Return the prefix index number (the number of times 99.Fa number 100must be divided to fit) instead of formatting it to the buffer. 101That is, the 102.Fa scale 103that would have been used if 104.Dv HN_AUTOSCALE 105had been used. 106.El 107.Pp 108The following flags may be passed in 109.Pa flags : 110.Bl -tag -width Dv -offset indent 111.It Dv HN_DECIMAL 112If the final numeric result is less than 10, 113and is not the same as the original value (that is, it has been scaled) 114display it using a decimal radix character, and one following digit. 115.It Dv HN_NOSPACE 116Do not put a space between 117.Fa number 118and the prefix. 119.It Dv HN_B 120Use 'B' (bytes) as prefix if the original result does not have a prefix. 121.It Dv HN_DIVISOR_1000 122Divide 123.Fa number 124with 1000 instead of 1024. 125That is, use decimal scaling instead of binary. 126.El 127.Pp 128To generate the shortest meaningful value, 129a buffer length 130.Pq Fa len 131that is 6 greater the length of the 132.Fa suffix 133along with 134.Dv HN_AUTOSCALE 135will ensure the highest meaningful scale is used. 136Allow one extra byte for the sign if the number is negative, 137and one less if the 138.Dv HN_NOSPACE 139flag is used. 140.Pp 141The 142.Fn dehumanize_number 143function parses the string representing an integral value given in 144.Fa str 145and stores the numerical value in the integer pointed to by 146.Fa result . 147The provided string may hold one of the suffixes, which will be interpreted 148and used to scale up its accompanying numerical value. 149.Sh RETURN VALUES 150.Fn humanize_number 151returns the number of characters stored in 152.Fa buffer 153(excluding the terminating NUL) upon success, or \-1 upon failure. 154If 155.Dv HN_GETSCALE 156is specified, the prefix index number will be returned instead. 157.Pp 158.Fn dehumanize_number 159returns 0 if the string was parsed correctly. 160A \-1 is returned to indicate failure and an error code is stored in 161.Va errno . 162.Sh ERRORS 163.Fn dehumanize_number 164will fail and no number will be stored in 165.Fa result 166if: 167.Bl -tag -width Er 168.It Bq Er EINVAL 169The string in 170.Fa str 171was empty or carried an unknown suffix. 172.It Bq Er ERANGE 173The string in 174.Fa str 175represented a number that does not fit in 176.Fa result . 177.El 178.Sh SEE ALSO 179.Xr strsuftoll 3 , 180.Xr orders 7 , 181.Xr humanize_number 9 182.Sh HISTORY 183.Fn humanize_number 184first appeared in 185.Nx 2.0 . 186.Pp 187.Fn dehumanize_number 188first appeared in 189.Nx 5.0 . 190