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/* This code is part of the tng compression routines.
*
* Written by Daniel Spangberg
* Copyright (c) 2010, 2013, The GROMACS development team.
*
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public License
* as published by the Free Software Foundation; either version 2.1
* of the License, or (at your option) any later version.
*/
#if HAVE_CONFIG_H
#include <config.h>
#endif
#include <stdio.h>
#include <math.h>
#include "fixpoint.h"
#define MAX32BIT 4294967295UL
#define MAX31BIT 2147483647UL
#define SIGN32BIT 2147483648UL
/* Conversion routines from / to double precision */
/* Positive double to 32 bit fixed point value */
fix_t Ptngc_ud_to_fix_t(double d,double max)
{
fix_t val;
if (d<0.)
d=0.;
if (d>max)
d=max;
val=(fix_t)(MAX32BIT*(d/max));
if (val>MAX32BIT)
val=MAX32BIT;
return val;
}
/* double to signed 32 bit fixed point value */
fix_t Ptngc_d_to_fix_t(double d,double max)
{
fix_t val;
int sign=0;
if (d<0.)
{
sign=1;
d=-d;
}
if (d>max)
d=max;
val=(fix_t)(MAX31BIT*(d/max));
if (val>MAX31BIT)
val=MAX31BIT;
if (sign)
val|=SIGN32BIT;
return val;
}
/* 32 bit fixed point value to positive double */
double Ptngc_fix_t_to_ud(fix_t f, double max)
{
return (double)f*(max/MAX32BIT);
}
/* signed 32 bit fixed point value to double */
double Ptngc_fix_t_to_d(fix_t f, double max)
{
int sign=0;
double d;
if (f&SIGN32BIT)
{
sign=1;
f&=MAX31BIT;
}
d=(double)f*(max/MAX31BIT);
if (sign)
d=-d;
return d;
}
/* Convert a floating point variable to two 32 bit integers with range
-2.1e9 to 2.1e9 and precision to somewhere around 1e-9. */
void Ptngc_d_to_i32x2(double d, fix_t *hi, fix_t *lo)
{
int sign=0;
double frac;
double ent;
fix_t val,vallo;
if (d<0.)
{
sign=1;
d=-d;
}
/* First the integer part */
ent=floor(d);
/* Then the fractional part */
frac=d-ent;
val=(fix_t)ent;
if (sign)
val|=SIGN32BIT;
vallo=Ptngc_ud_to_fix_t(frac,1.);
*hi=val;
*lo=vallo;
}
/* Convert two 32 bit integers to a floating point variable
-2.1e9 to 2.1e9 and precision to somewhere around 1e-9. */
double Ptngc_i32x2_to_d(fix_t hi, fix_t lo)
{
double ent,frac=0.;
double val=0.;
int sign=0;
if (hi&SIGN32BIT)
{
sign=1;
hi&=MAX31BIT;
}
ent=(double)hi;
frac=Ptngc_fix_t_to_ud(lo,1.);
val=ent+frac;
if (sign)
val=-val;
return val;
}
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