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lvm2/lib/misc/lvm-percent.h
Petr Rockai 8191fe4f4a Refactor the percent (mirror sync, snapshot usage) handling code to use
fixed-point values instead of a combination of a float value and an enum.
2010-11-30 11:53:31 +00:00

44 lines
1.4 KiB
C

/*
* Copyright (C) 2010 Red Hat, Inc. All rights reserved.
*
* This file is part of LVM2.
*
* This copyrighted material is made available to anyone wishing to use,
* modify, copy, or redistribute it subject to the terms and conditions
* of the GNU Lesser General Public License v.2.1.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program; if not, write to the Free Software Foundation,
* Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#ifndef _LVM_PERCENT_H
#define _LVM_PERCENT_H
#include <stdint.h>
/*
* A fixed-point representation of percent values. One percent equals to
* PERCENT_1 as defined below. Values that are not multiples of PERCENT_1
* represent fractions, with precision of 1/1000000 of a percent. See
* percent_to_float for a conversion to a floating-point representation.
*
* You should always use make_percent when building percent_t values. The
* implementation of make_percent is biased towards the middle: it ensures that
* the result is PERCENT_0 or PERCENT_100 if and only if this is the actual
* value -- it never rounds any intermediate value (> 0 or < 100) to either 0
* or 100.
*/
typedef int32_t percent_t;
typedef enum {
PERCENT_0 = 0,
PERCENT_1 = 1000000,
PERCENT_100 = 100 * PERCENT_1,
PERCENT_INVALID = -1
} percent_range_t;
float percent_to_float(percent_t v);
percent_t make_percent(uint64_t numerator, uint64_t denominator);
#endif