1 /* $OpenBSD: fmt_scaled.c,v 1.22 2022/03/11 09:04:59 dtucker Exp $ */
4 * Copyright (c) 2001, 2002, 2003 Ian F. Darwin. All rights reserved.
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7 * modification, are permitted provided that the following conditions
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30 * fmt_scaled: Format numbers scaled for human comprehension
31 * scan_scaled: Scan numbers in this format.
33 * "Human-readable" output uses 4 digits max, and puts a unit suffix at
34 * the end. Makes output compact and easy-to-read esp. on huge disks.
35 * Formatting code was originally in OpenBSD "df", converted to library routine.
36 * Scanning code written for OpenBSD libutil.
49 NONE = 0, KILO = 1, MEGA = 2, GIGA = 3, TERA = 4, PETA = 5, EXA = 6
52 /* These three arrays MUST be in sync! XXX make a struct */
53 static const unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA };
54 static const char scale_chars[] = "BKMGTPE";
55 static const long long scale_factors[] = {
60 1024LL*1024*1024*1024,
61 1024LL*1024*1024*1024*1024,
62 1024LL*1024*1024*1024*1024*1024,
64 #define SCALE_LENGTH (sizeof(units)/sizeof(units[0]))
66 #define MAX_DIGITS (SCALE_LENGTH * 3) /* XXX strlen(sprintf("%lld", -1)? */
68 /* Convert the given input string "scaled" into numeric in "result".
69 * Return 0 on success, -1 and errno set on error.
72 scan_scaled(char *scaled, long long *result)
76 unsigned int i, ndigits = 0, fract_digits = 0;
77 long long scale_fact = 1, whole = 0, fpart = 0;
79 /* Skip leading whitespace */
80 while (isascii((unsigned char)*p) && isspace((unsigned char)*p))
83 /* Then at most one leading + or - */
84 while (*p == '-' || *p == '+') {
92 } else if (*p == '+') {
102 /* Main loop: Scan digits, find decimal point, if present.
103 * We don't allow exponentials, so no scientific notation
104 * (but note that E for Exa might look like e to some!).
105 * Advance 'p' to end, to get scale factor.
107 for (; isascii((unsigned char)*p) &&
108 (isdigit((unsigned char)*p) || *p=='.'); ++p) {
110 if (fract_digits > 0) { /* oops, more than one '.' */
118 i = (*p) - '0'; /* whew! finally a digit we can use */
119 if (fract_digits > 0) {
120 if (fract_digits >= MAX_DIGITS-1)
121 /* ignore extra fractional digits */
123 fract_digits++; /* for later scaling */
124 if (fpart > LLONG_MAX / 10) {
129 if (i > LLONG_MAX - fpart) {
134 } else { /* normal digit */
135 if (++ndigits >= MAX_DIGITS) {
139 if (whole > LLONG_MAX / 10) {
144 if (i > LLONG_MAX - whole) {
155 /* If no scale factor given, we're done. fraction is discarded. */
161 /* Validate scale factor, and scale whole and fraction by it. */
162 for (i = 0; i < SCALE_LENGTH; i++) {
164 /* Are we there yet? */
165 if (*p == scale_chars[i] ||
166 *p == tolower((unsigned char)scale_chars[i])) {
168 /* If it ends with alphanumerics after the scale char, bad. */
169 if (isalnum((unsigned char)*(p+1))) {
173 scale_fact = scale_factors[i];
175 /* check for overflow and underflow after scaling */
176 if (whole > LLONG_MAX / scale_fact ||
177 whole < LLONG_MIN / scale_fact) {
182 /* scale whole part */
185 /* truncate fpart so it does't overflow.
186 * then scale fractional part.
188 while (fpart >= LLONG_MAX / scale_fact) {
193 if (fract_digits > 0) {
194 for (i = 0; i < fract_digits -1; i++)
206 /* Invalid unit or character */
211 /* Format the given "number" into human-readable form in "result".
212 * Result must point to an allocated buffer of length FMT_SCALED_STRSIZE.
213 * Return 0 on success, -1 and errno set if error.
216 fmt_scaled(long long number, char *result)
218 long long abval, fract = 0;
220 unit_type unit = NONE;
222 /* Not every negative long long has a positive representation. */
223 if (number == LLONG_MIN) {
228 abval = llabs(number);
230 /* Also check for numbers that are just too darned big to format. */
231 if (abval / 1024 >= scale_factors[SCALE_LENGTH-1]) {
236 /* scale whole part; get unscaled fraction */
237 for (i = 0; i < SCALE_LENGTH; i++) {
238 if (abval/1024 < scale_factors[i]) {
240 fract = (i == 0) ? 0 : abval % scale_factors[i];
241 number /= scale_factors[i];
243 fract /= scale_factors[i - 1];
248 fract = (10 * fract + 512) / 1024;
249 /* if the result would be >= 10, round main number */
256 } else if (fract < 0) {
257 /* shouldn't happen */
262 strlcpy(result, "0B", FMT_SCALED_STRSIZE);
263 else if (unit == NONE || number >= 100 || number <= -100) {
270 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld%c",
271 number, scale_chars[unit]);
273 (void)snprintf(result, FMT_SCALED_STRSIZE, "%lld.%1lld%c",
274 number, fract, scale_chars[unit]);
281 * This is the original version of the program in the man page.
282 * Copy-and-paste whatever you need from it.
285 main(int argc, char **argv)
287 char *cinput = "1.5K", buf[FMT_SCALED_STRSIZE];
288 long long ninput = 10483892, result;
290 if (scan_scaled(cinput, &result) == 0)
291 printf("\"%s\" -> %lld\n", cinput, result);
295 if (fmt_scaled(ninput, buf) == 0)
296 printf("%lld -> \"%s\"\n", ninput, buf);
298 fprintf(stderr, "%lld invalid (%s)\n", ninput, strerror(errno));