/* $OpenBSD: fmt_scaled.c,v 1.17 2018/05/14 04:39:04 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 unit_type units[] = { NONE, KILO, MEGA, GIGA, TERA, PETA, EXA }; static char scale_chars[] = "BKMGTPE"; static 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; 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; fpart *= 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; /* truncate fpart so it doesn't overflow. * then scale fractional part. */ while (fpart >= LLONG_MAX / scale_fact) { fpart /= 10; fract_digits--; } fpart *= scale_fact; if (fract_digits > 0) { for (i = 0; i < fract_digits -1; i++) fpart /= 10; } 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; abval = llabs(number); /* Not every negative long long has a positive representation. * Also check for numbers that are just too darned big to format */ if (abval < 0 || 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 */