```
/* human.h -- print human readable file size
Copyright (C) 1996-2007, 2009-2018 Free Software Foundation, Inc.
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 3 of the License, or
(at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>. */
/* Written by Paul Eggert and Larry McVoy. */
#ifndef HUMAN_H_
# define HUMAN_H_ 1
# include <limits.h>
# include <stdbool.h>
# include <stdint.h>
# include <unistd.h>
# include <xstrtol.h>
/* A conservative bound on the maximum length of a human-readable string.
The output can be the square of the largest uintmax_t, so double
its size before converting to a bound.
log10 (2.0) < 146/485. Add 1 for integer division truncation.
Also, the output can have a thousands separator between every digit,
so multiply by MB_LEN_MAX + 1 and then subtract MB_LEN_MAX.
Append 1 for a space before the suffix.
Finally, append 3, the maximum length of a suffix. */
# define LONGEST_HUMAN_READABLE \
((2 * sizeof (uintmax_t) * CHAR_BIT * 146 / 485 + 1) * (MB_LEN_MAX + 1) \
- MB_LEN_MAX + 1 + 3)
/* Options for human_readable. */
enum
{
/* Unless otherwise specified these options may be ORed together. */
/* The following three options are mutually exclusive. */
/* Round to plus infinity (default). */
human_ceiling = 0,
/* Round to nearest, ties to even. */
human_round_to_nearest = 1,
/* Round to minus infinity. */
human_floor = 2,
/* Group digits together, e.g. "1,000,000". This uses the
locale-defined grouping; the traditional C locale does not group,
so this has effect only if some other locale is in use. */
human_group_digits = 4,
/* When autoscaling, suppress ".0" at end. */
human_suppress_point_zero = 8,
/* Scale output and use SI-style units, ignoring the output block size. */
human_autoscale = 16,
/* Prefer base 1024 to base 1000. */
human_base_1024 = 32,
/* Prepend " " before unit symbol. */
human_space_before_unit = 64,
/* Append SI prefix, e.g. "k" or "M". */
human_SI = 128,
/* Append "B" (if base 1000) or "iB" (if base 1024) to SI prefix. */
human_B = 256
};
char *human_readable (uintmax_t, char *, int, uintmax_t, uintmax_t);
enum strtol_error human_options (char const *, int *, uintmax_t *);
#endif /* HUMAN_H_ */
```