NAME
dehumanize_number,
humanize_number —
format a number into a human readable
form and vice versa
SYNOPSIS
#include
<stdlib.h>
int
dehumanize_number(const
char *str, int64_t
*result);
int
humanize_number(char
*buffer, size_t
len, int64_t
number, const char
*suffix, int scale,
int flags);
DESCRIPTION
Thehumanize_number()
function formats the signed 64 bit quantity given in
number into buffer. A space and
then the suffix (if not null) is appended to the end.
len gives the size of the buffer.
If the formatted number (including suffix) would be too long to fit into buffer, then repeatedly divide number by 1024 until it will fit. In this case, prefix suffix with the appropriate SI designator.
The prefixes are:
| Prefix | Description | Multiplier |
| k | kilo | 1024 |
| M | mega | 1048576 |
| G | giga | 1073741824 |
| T | tera | 1099511627776 |
| P | peta | 1125899906842624 |
| E | exa | 1152921504606846976 |
len must be at least 4 plus the length of suffix, in order to ensure a useful result is generated into buffer. To use a specific prefix, specify this as scale (Multiplier = 1024 ^ scale). The scale must be at least 0 and no more than 6.
Alternatively, one of the following special values may be given as scale:
HN_AUTOSCALE- Format the buffer using the lowest multiplier possible.
HN_GETSCALE- Return the prefix index number (the number of times
number must be divided to fit) instead of formatting
it to the buffer. That is, the scale that would have
been used if
HN_AUTOSCALEhad been used.
The following flags may be passed in flags:
HN_DECIMAL- If the final numeric result is less than 10, and is not the same as the original value (that is, it has been scaled) display it using a decimal radix character, and one following digit.
HN_NOSPACE- Do not put a space between number and the prefix.
HN_B- Use 'B' (bytes) as prefix if the original result does not have a prefix.
HN_DIVISOR_1000- Divide number with 1000 instead of 1024. That is, use decimal scaling instead of binary.
To generate the shortest meaningful value, a buffer length
(len) that is 6 greater the length of the
suffix along with HN_AUTOSCALE
will ensure the highest meaningful scale is used. Allow one extra byte for
the sign if the number is negative, and one less if the
HN_NOSPACE flag is used.
The
dehumanize_number()
function parses the string representing an integral value given in
str and stores the numerical value in the integer
pointed to by result. The provided string may hold one
of the suffixes, which will be interpreted and used to scale up its
accompanying numerical value.
RETURN VALUES
humanize_number() returns the number of
characters stored in buffer (excluding the terminating
NUL) upon success, or -1 upon failure. If
HN_GETSCALE is specified, the prefix index number
will be returned instead.
dehumanize_number() returns 0 if the
string was parsed correctly. A -1 is returned to indicate failure and an
error code is stored in errno.
ERRORS
dehumanize_number() will fail and no
number will be stored in result if:
- [
EINVAL] - The string in str was empty or carried an unknown suffix.
- [
ERANGE] - The string in str represented a number that does not fit in result.
SEE ALSO
HISTORY
humanize_number() first appeared in
NetBSD 2.0.
dehumanize_number() first appeared in
NetBSD 5.0.