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humanize_number.c revision 1.10 
      1 /*	$NetBSD: humanize_number.c,v 1.10 2005/09/13 01:44:09 christos 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  * 3. All advertising materials mentioning features or use of this software
     20  *    must display the following acknowledgement:
     21  *      This product includes software developed by the NetBSD
     22  *      Foundation, Inc. and its contributors.
     23  * 4. Neither the name of The NetBSD Foundation nor the names of its
     24  *    contributors may be used to endorse or promote products derived
     25  *    from this software without specific prior written permission.
     26  *
     27  * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
     28  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
     29  * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     30  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
     31  * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
     32  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
     33  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
     34  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
     35  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
     36  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
     37  * POSSIBILITY OF SUCH DAMAGE.
     38  */
     39 
     40 #include <sys/cdefs.h>
     41 #if defined(LIBC_SCCS) && !defined(lint)
     42 __RCSID("$NetBSD: humanize_number.c,v 1.10 2005/09/13 01:44:09 christos Exp $");
     43 #endif /* LIBC_SCCS and not lint */
     44 
     45 #include "namespace.h"
     46 #include <assert.h>
     47 #include <stdio.h>
     48 #include <stdlib.h>
     49 #include <string.h>
     50 #include <locale.h>
     51 #include <util.h>
     52 
     53 int
     54 humanize_number(char *buf, size_t len, int64_t bytes,
     55     const char *suffix, int scale, int flags)
     56 {
     57 	const char *prefixes, *sep;
     58 	int	b, i, r, maxscale, s1, s2, sign;
     59 	int64_t	divisor, max;
     60 	size_t	baselen;
     61 
     62 	_DIAGASSERT(buf != NULL);
     63 	_DIAGASSERT(suffix != NULL);
     64 	_DIAGASSERT(scale >= 0);
     65 
     66 	if (flags & HN_DIVISOR_1000) {
     67 		/* SI for decimal multiplies */
     68 		divisor = 1000;
     69 		if (flags & HN_B)
     70 			prefixes = "B\0k\0M\0G\0T\0P\0E";
     71 		else
     72 			prefixes = "\0\0k\0M\0G\0T\0P\0E";
     73 	} else {
     74 		/*
     75 		 * binary multiplies
     76 		 * XXX IEC 60027-2 recommends Ki, Mi, Gi...
     77 		 */
     78 		divisor = 1024;
     79 		if (flags & HN_B)
     80 			prefixes = "B\0K\0M\0G\0T\0P\0E";
     81 		else
     82 			prefixes = "\0\0K\0M\0G\0T\0P\0E";
     83 	}
     84 
     85 #define	SCALE2PREFIX(scale)	(&prefixes[(scale) << 1])
     86 	maxscale = 7;
     87 
     88 	if (scale >= maxscale &&
     89 	    (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)
     90 		return (-1);
     91 
     92 	if (buf == NULL || suffix == NULL)
     93 		return (-1);
     94 
     95 	if (len > 0)
     96 		buf[0] = '\0';
     97 	if (bytes < 0) {
     98 		sign = -1;
     99 		bytes *= -100;
    100 		baselen = 3;		/* sign, digit, prefix */
    101 	} else {
    102 		sign = 1;
    103 		bytes *= 100;
    104 		baselen = 2;		/* digit, prefix */
    105 	}
    106 	if (flags & HN_NOSPACE)
    107 		sep = "";
    108 	else {
    109 		sep = " ";
    110 		baselen++;
    111 	}
    112 	baselen += strlen(suffix);
    113 
    114 	/* Check if enough room for `x y' + suffix + `\0' */
    115 	if (len < baselen + 1)
    116 		return (-1);
    117 
    118 	if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
    119 		/* See if there is additional columns can be used. */
    120 		for (max = 100, i = len - baselen; i-- > 0;)
    121 			max *= 10;
    122 
    123 		for (i = 0; bytes >= max && i < maxscale; i++)
    124 			bytes /= divisor;
    125 
    126 		if (scale & HN_GETSCALE)
    127 			return (i);
    128 	} else
    129 		for (i = 0; i < scale && i < maxscale; i++)
    130 			bytes /= divisor;
    131 
    132 	/* If a value <= 9.9 after rounding and ... */
    133 	if (bytes < 995 && i > 0 && flags & HN_DECIMAL) {
    134 		/* baselen + \0 + .N */
    135 		if (len < baselen + 1 + 2)
    136 			return (-1);
    137 		b = ((int)bytes + 5) / 10;
    138 		s1 = b / 10;
    139 		s2 = b % 10;
    140 		r = snprintf(buf, len, "%d%s%d%s%s%s",
    141 		    sign * s1, localeconv()->decimal_point, s2,
    142 		    sep, SCALE2PREFIX(i), suffix);
    143 	} else
    144 		r = snprintf(buf, len, "%lld%s%s%s",
    145 		    /* LONGLONG */
    146 		    (long long)(sign * ((bytes + 50) / 100)),
    147 		    sep, SCALE2PREFIX(i), suffix);
    148 
    149 	return (r);
    150 }
    151