humanize_number.c

/*      $NetBSD: humanize_number.c,v 1.14 2008/04/28 20:22:59 martin Exp $      */
 
/*
 * Copyright (c) 1997, 1998, 1999, 2002 The NetBSD Foundation, Inc.
 * All rights reserved.
 *
 * This code is derived from software contributed to The NetBSD Foundation
 * by Jason R. Thorpe of the Numerical Aerospace Simulation Facility,
 * NASA Ames Research Center, by Luke Mewburn and by Tomas Svensson.
 *
 * 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.
 *
 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
 * ``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 FOUNDATION OR CONTRIBUTORS
 * 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.
 */
 
#include <assert.h>
#include <inttypes.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <locale.h>
 
#include "xbps_api_impl.h"
#include "compat.h"
 
int HIDDEN
humanize_number(char *buf, size_t len, int64_t bytes,
                const char *suffix, int scale, int flags)
{
        const char *prefixes, *sep;
        int     b, i, r, maxscale, s1, s2, sign;
        int64_t divisor, max;
        size_t  baselen;
 
        assert(buf != NULL);
        assert(suffix != NULL);
        assert(scale >= 0);
 
        if (flags & HN_DIVISOR_1000) {
                /* SI for decimal multiplies */
                divisor = 1000;
                if (flags & HN_B)
                        prefixes = "B\0k\0M\0G\0T\0P\0E";
                else
                        prefixes = "\0\0k\0M\0G\0T\0P\0E";
        } else {
                /*
                 * binary multiplies
                 * XXX IEC 60027-2 recommends Ki, Mi, Gi...
                 */
                divisor = 1024;
                if (flags & HN_B)
                        prefixes = "B\0K\0M\0G\0T\0P\0E";
                else
                        prefixes = "\0\0K\0M\0G\0T\0P\0E";
        }
 
#define SCALE2PREFIX(scale)     (&prefixes[(scale) << 1])
        maxscale = 7;
 
        if (scale >= maxscale &&
            (scale & (HN_AUTOSCALE | HN_GETSCALE)) == 0)
                return (-1);
 
        if (buf == NULL || suffix == NULL)
                return (-1);
 
        if (len > 0)
                buf[0] = '\0';
        if (bytes < 0) {
                sign = -1;
                bytes *= -100;
                baselen = 3;            /* sign, digit, prefix */
        } else {
                sign = 1;
                bytes *= 100;
                baselen = 2;            /* digit, prefix */
        }
        if (flags & HN_NOSPACE)
                sep = "";
        else {
                sep = " ";
                baselen++;
        }
        baselen += strlen(suffix);
 
        /* Check if enough room for `x y' + suffix + `\0' */
        if (len < baselen + 1)
                return (-1);
 
        if (scale & (HN_AUTOSCALE | HN_GETSCALE)) {
                /* See if there is additional columns can be used. */
                for (max = 100, i = (int)(len - baselen); i-- > 0;)
                        max *= 10;
 
                /*
                 * Divide the number until it fits the given column.
                 * If there will be an overflow by the rounding below,
                 * divide once more.
                 */
                for (i = 0; bytes >= max - 50 && i < maxscale; i++)
                        bytes /= divisor;
 
                if (scale & HN_GETSCALE)
                        return (i);
        } else
                for (i = 0; i < scale && i < maxscale; i++)
                        bytes /= divisor;
 
        /* If a value <= 9.9 after rounding and ... */
        if (bytes < 995 && i > 0 && flags & HN_DECIMAL) {
                /* baselen + \0 + .N */
                if (len < baselen + 1 + 2)
                        return (-1);
                b = ((int)bytes + 5) / 10;
                s1 = b / 10;
                s2 = b % 10;
                r = snprintf(buf, len, "%d%s%d%s%s%s",
                    sign * s1, localeconv()->decimal_point, s2,
                    sep, SCALE2PREFIX(i), suffix);
        } else
                r = snprintf(buf, len, "%" PRId64 "%s%s%s",
                    sign * ((bytes + 50) / 100),
                    sep, SCALE2PREFIX(i), suffix);
 
        return (r);
}