/src/openssh/openbsd-compat/fmt_scaled.c

Source
/*  $OpenBSD: fmt_scaled.c,v 1.25 2026/06/06 23:53:59 djm Exp $ */

/*
 * Copyright (c) 2001, 2002, 2003 Ian F. Darwin.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

/* OPENBSD ORIGINAL: lib/libutil/fmt_scaled.c */

/*
 * fmt_scaled: Format numbers scaled for human comprehension
 * scan_scaled: Scan numbers in this format.
 *
 * "Human-readable" output uses 4 digits max, and puts a unit suffix at
 * the end.  Makes output compact and easy-to-read esp. on huge disks.
 * Formatting code was originally in OpenBSD "df", converted to library routine.
 * Scanning code written for OpenBSD libutil.
 */

#include "includes.h"

#ifndef HAVE_FMT_SCALED

#include <stdio.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <ctype.h>
#include <limits.h>

typedef enum {
  NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
} unit_type;

/* These three arrays MUST be in sync!  XXX make a struct */
static const unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
static const char scale_chars[] = "BKMGTPE";
static const long long scale_factors[] = {
  1LL,
  1024LL,
  1024LL*1024,
  1024LL*1024*1024,
  1024LL*1024*1024*1024,
  1024LL*1024*1024*1024*1024,
  1024LL*1024*1024*1024*1024*1024,
};
#define SCALE_LENGTH (sizeof(units)/sizeof(units[0]))

#define MAX_DIGITS (SCALE_LENGTH * 3)  /* XXX strlen(sprintf("%lld", -1)? */

/* Convert the given input string "scaled" into numeric in "result".
 * Return 0 on success, -1 and errno set on error.
 */
int
scan_scaled(char *scaled, long long *result)
{
  char *p = scaled;
  int sign = 0;
  unsigned int i, ndigits = 0, fract_digits = 0, muls = 0, divs = 0;
  long long scale_fact = 1, whole = 0, fpart = 0;

  /* Skip leading whitespace */
  while (isascii((unsigned char)*p) && isspace((unsigned char)*p))
    ++p;

  /* Then at most one leading + or - */
  while (*p == '-' || *p == '+') {
    if (*p == '-') {
      if (sign) {
        errno = EINVAL;
        return -1;
      }
      sign = -1;
      ++p;
    } else if (*p == '+') {
      if (sign) {
        errno = EINVAL;
        return -1;
      }
      sign = +1;
      ++p;
    }
  }

  /* Main loop: Scan digits, find decimal point, if present.
   * We don't allow exponentials, so no scientific notation
   * (but note that E for Exa might look like e to some!).
   * Advance 'p' to end, to get scale factor.
   */
  for (; isascii((unsigned char)*p) &&
      (isdigit((unsigned char)*p) || *p=='.'); ++p) {
    if (*p == '.') {
      if (fract_digits > 0) { /* oops, more than one '.' */
        errno = EINVAL;
        return -1;
      }
      fract_digits = 1;
      continue;
    }

    i = (*p) - '0';     /* whew! finally a digit we can use */
    if (fract_digits > 0) {
      if (fract_digits >= MAX_DIGITS-1)
        /* ignore extra fractional digits */
        continue;
      fract_digits++;   /* for later scaling */
      if (fpart > LLONG_MAX / 10) {
        errno = ERANGE;
        return -1;
      }
      fpart *= 10;
      if (i > LLONG_MAX - fpart) {
        errno = ERANGE;
        return -1;
      }
      fpart += i;
    } else {       /* normal digit */
      if (++ndigits >= MAX_DIGITS) {
        errno = ERANGE;
        return -1;
      }
      if (whole > LLONG_MAX / 10) {
        errno = ERANGE;
        return -1;
      }
      whole *= 10;
      if (i > LLONG_MAX - whole) {
        errno = ERANGE;
        return -1;
      }
      whole += i;
    }
  }

  if (sign)
    whole *= sign;

  /* If no scale factor given, we're done. fraction is discarded. */
  if (!*p) {
    *result = whole;
    return 0;
  }

  /* Validate scale factor, and scale whole and fraction by it. */
  for (i = 0; i < SCALE_LENGTH; i++) {

    /* Are we there yet? */
    if (*p == scale_chars[i] ||
      *p == tolower((unsigned char)scale_chars[i])) {

      /* If it ends with alphanumerics after the scale char, bad. */
      if (isalnum((unsigned char)*(p+1))) {
        errno = EINVAL;
        return -1;
      }
      scale_fact = scale_factors[i];

      /* check for overflow and underflow after scaling */
      if (whole > LLONG_MAX / scale_fact ||
          whole < LLONG_MIN / scale_fact) {
        errno = ERANGE;
        return -1;
      }

      /* scale whole part */
      whole *= scale_fact;

      /*
       * Scale fractional part: compute
       *   fpart * scale_fact / 10^(fract_digits-1)
       * without intermediate overflow. scale_fact is 1024^i,
       * i.e. a power of 1024 = 2^10. Interleave
       * multiply-by-1024 with divide-by-10 so the running
       * value stays within long long range while preserving
       * precision.
       */
      muls = i;
      divs = fract_digits > 0 ?  fract_digits - 1 : 0;
      while (muls > 0 && divs > 0) {
        if (fpart <= LLONG_MAX / 1024) {
          fpart *= 1024;
          muls--;
        } else {
          fpart /= 10;
          divs--;
        }
      }
      while (muls > 0) {
        fpart *= 1024;
        muls--;
      }
      while (divs > 0) {
        fpart /= 10;
        divs--;
      }
      if (sign == -1)
        whole -= fpart;
      else
        whole += fpart;
      *result = whole;
      return 0;
    }
  }

  /* Invalid unit or character */
  errno = EINVAL;
  return -1;
}

/* Format the given "number" into human-readable form in "result".
 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
 * Return 0 on success, -1 and errno set if error.
 */
int
fmt_scaled(long long number, char *result)
{
  long long abval, fract = 0;
  unsigned int i;
  unit_type unit = NONE;

  /* Not every negative long long has a positive representation. */
  if (number == LLONG_MIN) {
    errno = ERANGE;
    return -1;
  }

  abval = llabs(number);

  /* Also check for numbers that are just too darned big to format. */
  if (abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
    errno = ERANGE;
    return -1;
  }

  /* scale whole part; get unscaled fraction */
  for (i = 0; i < SCALE_LENGTH; i++) {
    if (abval/1024 < scale_factors[i]) {
      unit = units[i];
      fract = (i == 0) ? 0 : abval % scale_factors[i];
      number /= scale_factors[i];
      if (i > 0)
        fract /= scale_factors[i - 1];
      break;
    }
  }

  fract = (10 * fract + 512) / 1024;
  /* if the result would be >= 10, round main number */
  if (fract >= 10) {
    if (number >= 0)
      number++;
    else
      number--;
    fract = 0;
  } else if (fract < 0) {
    /* shouldn't happen */
    fract = 0;
  }

  if (number == 0)
    strlcpy(result, "0B", FMT_SCALED_STRSIZE);
  else if (unit == NONE || number >= 100 || number <= -100) {
    if (fract >= 5) {
      if (number >= 0)
        number++;
      else
        number--;
    }
    (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
      number, scale_chars[unit]);
  } else
    (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
      number, fract, scale_chars[unit]);

  return 0;
}

#ifdef  MAIN
/*
 * This is the original version of the program in the man page.
 * Copy-and-paste whatever you need from it.
 */
int
main(int argc, char **argv)
{
  char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
  long long ninput = 10483892, result;

  if (scan_scaled(cinput, &result) == 0)
    printf("\"%s\" -> %lld\n", cinput, result);
  else
    perror(cinput);

  if (fmt_scaled(ninput, buf) == 0)
    printf("%lld -> \"%s\"\n", ninput, buf);
  else
    fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));

  return 0;
}
#endif

#endif /* HAVE_FMT_SCALED */

Coverage Report

Created: 2026-07-10 07:10

Line	Count	Source
1		/* $OpenBSD: fmt_scaled.c,v 1.25 2026/06/06 23:53:59 djm Exp $ */
2
3		/*
4		* Copyright (c) 2001, 2002, 2003 Ian F. Darwin. All rights reserved.
5		*
6		* Redistribution and use in source and binary forms, with or without
7		* modification, are permitted provided that the following conditions
8		* are met:
9		* 1. Redistributions of source code must retain the above copyright
10		* notice, this list of conditions and the following disclaimer.
11		* 2. Redistributions in binary form must reproduce the above copyright
12		* notice, this list of conditions and the following disclaimer in the
13		* documentation and/or other materials provided with the distribution.
14		* 3. The name of the author may not be used to endorse or promote products
15		* derived from this software without specific prior written permission.
16		*
17		* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18		* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19		* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20		* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21		* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22		* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23		* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24		* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25		* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26		* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27		*/
28
29		/* OPENBSD ORIGINAL: lib/libutil/fmt_scaled.c */
30
31		/*
32		* fmt_scaled: Format numbers scaled for human comprehension
33		* scan_scaled: Scan numbers in this format.
34		*
35		* "Human-readable" output uses 4 digits max, and puts a unit suffix at
36		* the end. Makes output compact and easy-to-read esp. on huge disks.
37		* Formatting code was originally in OpenBSD "df", converted to library routine.
38		* Scanning code written for OpenBSD libutil.
39		*/
40
41		#include "includes.h"
42
43		#ifndef HAVE_FMT_SCALED
44
45		#include <stdio.h>
46		#include <stdlib.h>
47		#include <errno.h>
48		#include <string.h>
49		#include <ctype.h>
50		#include <limits.h>
51
52		typedef enum {
53		NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
54		} unit_type;
55
56		/* These three arrays MUST be in sync! XXX make a struct */
57		static const unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
58		static const char scale_chars[] = "BKMGTPE";
59		static const long long scale_factors[] = {
60		1LL,
61		1024LL,
62		1024LL*1024,
63		1024LL10241024,
64		1024LL10241024*1024,
65		1024LL1024102410241024,
66		1024LL1024102410241024*1024,
67		};
68	0	#define SCALE_LENGTH (sizeof(units)/sizeof(units[0]))
69
70	0	#define MAX_DIGITS (SCALE_LENGTH * 3) /* XXX strlen(sprintf("%lld", -1)? */
71
72		/* Convert the given input string "scaled" into numeric in "result".
73		* Return 0 on success, -1 and errno set on error.
74		*/
75		int
76		scan_scaled(char scaled, long long result)
77	0	{
78	0	char *p = scaled;
79	0	int sign = 0;
80	0	unsigned int i, ndigits = 0, fract_digits = 0, muls = 0, divs = 0;
81	0	long long scale_fact = 1, whole = 0, fpart = 0;
82
83		/* Skip leading whitespace */
84	0	while (isascii((unsigned char)p) && isspace((unsigned char)p))
85	0	++p;
86
87		/* Then at most one leading + or - */
88	0	while (p == '-' \|\| p == '+') {
89	0	if (*p == '-') {
90	0	if (sign) {
91	0	errno = EINVAL;
92	0	return -1;
93	0	}
94	0	sign = -1;
95	0	++p;
96	0	} else if (*p == '+') {
97	0	if (sign) {
98	0	errno = EINVAL;
99	0	return -1;
100	0	}
101	0	sign = +1;
102	0	++p;
103	0	}
104	0	}
105
106		/* Main loop: Scan digits, find decimal point, if present.
107		* We don't allow exponentials, so no scientific notation
108		* (but note that E for Exa might look like e to some!).
109		* Advance 'p' to end, to get scale factor.
110		*/
111	0	for (; isascii((unsigned char)*p) &&
112	0	(isdigit((unsigned char)p) \|\| p=='.'); ++p) {
113	0	if (*p == '.') {
114	0	if (fract_digits > 0) { /* oops, more than one '.' */
115	0	errno = EINVAL;
116	0	return -1;
117	0	}
118	0	fract_digits = 1;
119	0	continue;
120	0	}
121
122	0	i = (p) - '0'; / whew! finally a digit we can use */
123	0	if (fract_digits > 0) {
124	0	if (fract_digits >= MAX_DIGITS-1)
125		/* ignore extra fractional digits */
126	0	continue;
127	0	fract_digits++; /* for later scaling */
128	0	if (fpart > LLONG_MAX / 10) {
129	0	errno = ERANGE;
130	0	return -1;
131	0	}
132	0	fpart *= 10;
133	0	if (i > LLONG_MAX - fpart) {
134	0	errno = ERANGE;
135	0	return -1;
136	0	}
137	0	fpart += i;
138	0	} else { /* normal digit */
139	0	if (++ndigits >= MAX_DIGITS) {
140	0	errno = ERANGE;
141	0	return -1;
142	0	}
143	0	if (whole > LLONG_MAX / 10) {
144	0	errno = ERANGE;
145	0	return -1;
146	0	}
147	0	whole *= 10;
148	0	if (i > LLONG_MAX - whole) {
149	0	errno = ERANGE;
150	0	return -1;
151	0	}
152	0	whole += i;
153	0	}
154	0	}
155
156	0	if (sign)
157	0	whole *= sign;
158
159		/* If no scale factor given, we're done. fraction is discarded. */
160	0	if (!*p) {
161	0	*result = whole;
162	0	return 0;
163	0	}
164
165		/* Validate scale factor, and scale whole and fraction by it. */
166	0	for (i = 0; i < SCALE_LENGTH; i++) {
167
168		/* Are we there yet? */
169	0	if (*p == scale_chars[i] \|\|
170	0	*p == tolower((unsigned char)scale_chars[i])) {
171
172		/* If it ends with alphanumerics after the scale char, bad. */
173	0	if (isalnum((unsigned char)*(p+1))) {
174	0	errno = EINVAL;
175	0	return -1;
176	0	}
177	0	scale_fact = scale_factors[i];
178
179		/* check for overflow and underflow after scaling */
180	0	if (whole > LLONG_MAX / scale_fact \|\|
181	0	whole < LLONG_MIN / scale_fact) {
182	0	errno = ERANGE;
183	0	return -1;
184	0	}
185
186		/* scale whole part */
187	0	whole *= scale_fact;
188
189		/*
190		* Scale fractional part: compute
191		* fpart * scale_fact / 10^(fract_digits-1)
192		* without intermediate overflow. scale_fact is 1024^i,
193		* i.e. a power of 1024 = 2^10. Interleave
194		* multiply-by-1024 with divide-by-10 so the running
195		* value stays within long long range while preserving
196		* precision.
197		*/
198	0	muls = i;
199	0	divs = fract_digits > 0 ? fract_digits - 1 : 0;
200	0	while (muls > 0 && divs > 0) {
201	0	if (fpart <= LLONG_MAX / 1024) {
202	0	fpart *= 1024;
203	0	muls--;
204	0	} else {
205	0	fpart /= 10;
206	0	divs--;
207	0	}
208	0	}
209	0	while (muls > 0) {
210	0	fpart *= 1024;
211	0	muls--;
212	0	}
213	0	while (divs > 0) {
214	0	fpart /= 10;
215	0	divs--;
216	0	}
217	0	if (sign == -1)
218	0	whole -= fpart;
219	0	else
220	0	whole += fpart;
221	0	*result = whole;
222	0	return 0;
223	0	}
224	0	}
225
226		/* Invalid unit or character */
227	0	errno = EINVAL;
228	0	return -1;
229	0	}
230
231		/* Format the given "number" into human-readable form in "result".
232		* Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
233		* Return 0 on success, -1 and errno set if error.
234		*/
235		int
236		fmt_scaled(long long number, char *result)
237	0	{
238	0	long long abval, fract = 0;
239	0	unsigned int i;
240	0	unit_type unit = NONE;
241
242		/* Not every negative long long has a positive representation. */
243	0	if (number == LLONG_MIN) {
244	0	errno = ERANGE;
245	0	return -1;
246	0	}
247
248	0	abval = llabs(number);
249
250		/* Also check for numbers that are just too darned big to format. */
251	0	if (abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
252	0	errno = ERANGE;
253	0	return -1;
254	0	}
255
256		/* scale whole part; get unscaled fraction */
257	0	for (i = 0; i < SCALE_LENGTH; i++) {
258	0	if (abval/1024 < scale_factors[i]) {
259	0	unit = units[i];
260	0	fract = (i == 0) ? 0 : abval % scale_factors[i];
261	0	number /= scale_factors[i];
262	0	if (i > 0)
263	0	fract /= scale_factors[i - 1];
264	0	break;
265	0	}
266	0	}
267
268	0	fract = (10 * fract + 512) / 1024;
269		/* if the result would be >= 10, round main number */
270	0	if (fract >= 10) {
271	0	if (number >= 0)
272	0	number++;
273	0	else
274	0	number--;
275	0	fract = 0;
276	0	} else if (fract < 0) {
277		/* shouldn't happen */
278	0	fract = 0;
279	0	}
280
281	0	if (number == 0)
282	0	strlcpy(result, "0B", FMT_SCALED_STRSIZE);
283	0	else if (unit == NONE \|\| number >= 100 \|\| number <= -100) {
284	0	if (fract >= 5) {
285	0	if (number >= 0)
286	0	number++;
287	0	else
288	0	number--;
289	0	}
290	0	(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
291	0	number, scale_chars[unit]);
292	0	} else
293	0	(void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
294	0	number, fract, scale_chars[unit]);
295
296	0	return 0;
297	0	}
298
299		#ifdef MAIN
300		/*
301		* This is the original version of the program in the man page.
302		* Copy-and-paste whatever you need from it.
303		*/
304		int
305		main(int argc, char **argv)
306		{
307		char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
308		long long ninput = 10483892, result;
309
310		if (scan_scaled(cinput, &result) == 0)
311		printf("\"%s\" -> %lld\n", cinput, result);
312		else
313		perror(cinput);
314
315		if (fmt_scaled(ninput, buf) == 0)
316		printf("%lld -> \"%s\"\n", ninput, buf);
317		else
318		fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));
319
320		return 0;
321		}
322		#endif
323
324		#endif /* HAVE_FMT_SCALED */