/* $NetBSD: strpct.c,v 1.2 1998/05/08 18:43:54 fair Exp $ */ /*- * Copyright (c) 1998 The NetBSD Foundation, Inc. * All rights reserved. * * This code is derived from software contributed to The NetBSD Foundation * by Erik E. Fair * * 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. All advertising materials mentioning features or use of this software * must display the following acknowledgement: * This product includes software developed by the NetBSD * Foundation, Inc. and its contributors. * 4. Neither the name of The NetBSD Foundation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * 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. */ /* * Calculate a percentage without resorting to floating point * and return a pointer to a string * * "digits" is the number of digits past the decimal place you want * (zero being the straight percentage with no decimals) * * Erik E. Fair <fair@clock.org>, May 8, 1997 */ #include <sys/types.h> #include <machine/limits.h> #include <stdio.h> char * strpct __P((u_long, u_long, u_int)); char * strpct(numerator, denominator, digits) u_long numerator, denominator; u_int digits; { int i; u_long result, factor; static char percent[32]; /* I should check for digit overflow here, too XXX */ factor = 100L; for(i = 0; i < digits; i++) { factor *= 10; } /* watch out for overflow! */ if (numerator < (ULONG_MAX / factor)) { numerator *= factor; } else { /* toss some of the bits of lesser significance */ denominator /= factor; } if (denominator == 0L) denominator = 1L; result = numerator / denominator; if (digits == 0) { (void) snprintf(percent, sizeof(percent), "%lu%%", result); } else { char fmt[32]; /* indirection to produce the right output format */ (void) snprintf(fmt, sizeof(fmt), "%%lu.%%0%ulu%%%%", digits); factor /= 100L; /* undo initialization */ (void) snprintf(percent, sizeof(percent), fmt, result / factor, result % factor); } return(percent); }