Home | History | Annotate | Line # | Download | only in gen
humanize_number.c revision 1.14.8.2 
      1 /*	$NetBSD: humanize_number.c,v 1.14.8.2 2008/04/28 20:23:00 martin Exp $	*/
      2 
      3 /*
      4  * Copyright (c) 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
      5  * All rights reserved.
      6  *
      7  * This code is derived from software contributed to The NetBSD Foundation
      8  * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
      9  * NASA Ames Research Center, by Luke Mewburn and by Tomas Svensson.
     10  *
     11  * Redistribution and use in source and binary forms, with or without
     12  * modification, are permitted provided that the following conditions
     13  * are met:
     14  * 1. Redistributions of source code must retain the above copyright
     15  *    notice, this list of conditions and the following disclaimer.
     16  * 2. Redistributions in binary form must reproduce the above copyright
     17  *    notice, this list of conditions and the following disclaimer in the
     18  *    documentation and/or other materials provided with the distribution.
     19  *
     20  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     21  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     22  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     23  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     24  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     30  * POSSIBILITY OF SUCH DAMAGE.
     31  */
     32 
     33 #include <sys/cdefs.h>
     34 #if defined(LIBC_SCCS) && !defined(lint)
     35 __RCSID("$NetBSD: humanize_number.c,v 1.14.8.2 2008/04/28 20:23:00 martin Exp $");
     36 #endif /* LIBC_SCCS and not lint */
     37 
     38 #include "namespace.h"
     39 #include <assert.h>
     40 #include <inttypes.h>
     41 #include <stdio.h>
     42 #include <stdlib.h>
     43 #include <string.h>
     44 #include <locale.h>
     45 
     46 int
     47 humanize_number(char *buf, size_t len, int64_t bytes,
     48     const char *suffix, int scale, int flags)
     49 {
     50 	const char *prefixes, *sep;
     51 	int	b, i, r, maxscale, s1, s2, sign;
     52 	int64_t	divisor, max;
     53 	size_t	baselen;
     54 
     55 	_DIAGASSERT(buf != NULL);
     56 	_DIAGASSERT(suffix != NULL);
     57 	_DIAGASSERT(scale >= 0);
     58 
     59 	if (flags & HN_DIVISOR_1000) {
     60 		/* SI for decimal multiplies */
     61 		divisor = 1000;
     62 		if (flags & HN_B)
     63 			prefixes = "B\0k\0M\0G\0T\0P\0E";
     64 		else
     65 			prefixes = "\0\0k\0M\0G\0T\0P\0E";
     66 	} else {
     67 		/*
     68 		 * binary multiplies
     69 		 * XXX IEC 60027-2 recommends Ki, Mi, Gi...
     70 		 */
     71 		divisor = 1024;
     72 		if (flags & HN_B)
     73 			prefixes = "B\0K\0M\0G\0T\0P\0E";
     74 		else
     75 			prefixes = "\0\0K\0M\0G\0T\0P\0E";
     76 	}
     77 
     78 #define	SCALE2PREFIX(scale)	(&prefixes[(scale) << 1])
     79 	maxscale = 7;
     80 
     81 	if (scale >= maxscale &&
     82 	    (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)
     83 		return (-1);
     84 
     85 	if (buf == NULL || suffix == NULL)
     86 		return (-1);
     87 
     88 	if (len > 0)
     89 		buf[0] = '\0';
     90 	if (bytes < 0) {
     91 		sign = -1;
     92 		bytes *= -100;
     93 		baselen = 3;		/* sign, digit, prefix */
     94 	} else {
     95 		sign = 1;
     96 		bytes *= 100;
     97 		baselen = 2;		/* digit, prefix */
     98 	}
     99 	if (flags & HN_NOSPACE)
    100 		sep = "";
    101 	else {
    102 		sep = " ";
    103 		baselen++;
    104 	}
    105 	baselen += strlen(suffix);
    106 
    107 	/* Check if enough room for `x y' + suffix + `\0' */
    108 	if (len < baselen + 1)
    109 		return (-1);
    110 
    111 	if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
    112 		/* See if there is additional columns can be used. */
    113 		for (max = 100, i = len - baselen; i-- > 0;)
    114 			max *= 10;
    115 
    116 		/*
    117 		 * Divide the number until it fits the given column.
    118 		 * If there will be an overflow by the rounding below,
    119 		 * divide once more.
    120 		 */
    121 		for (i = 0; bytes >= max - 50 && i < maxscale; i++)
    122 			bytes /= divisor;
    123 
    124 		if (scale & HN_GETSCALE)
    125 			return (i);
    126 	} else
    127 		for (i = 0; i < scale && i < maxscale; i++)
    128 			bytes /= divisor;
    129 
    130 	/* If a value <= 9.9 after rounding and ... */
    131 	if (bytes < 995 && i > 0 && flags & HN_DECIMAL) {
    132 		/* baselen + \0 + .N */
    133 		if (len < baselen + 1 + 2)
    134 			return (-1);
    135 		b = ((int)bytes + 5) / 10;
    136 		s1 = b / 10;
    137 		s2 = b % 10;
    138 		r = snprintf(buf, len, "%d%s%d%s%s%s",
    139 		    sign * s1, localeconv()->decimal_point, s2,
    140 		    sep, SCALE2PREFIX(i), suffix);
    141 	} else
    142 		r = snprintf(buf, len, "%" PRId64 "%s%s%s",
    143 		    sign * ((bytes + 50) / 100),
    144 		    sep, SCALE2PREFIX(i), suffix);
    145 
    146 	return (r);
    147 }
    148