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/**************************************************************************/
/*!
@file IEEE11073float.h
*/
/**************************************************************************/
/**
* \file bytelib.c
* \brief Byte manipulation module implementation.
* Copyright (C) 2010 Signove Tecnologia Corporation.
* All rights reserved.
* Contact: Signove Tecnologia Corporation (contact@signove.com)
*
* $LICENSE_TEXT:BEGIN$
* This library 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 and appearing
* in the file LICENSE included in the packaging of this file; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
* $LICENSE_TEXT:END$
*
* \author Walter Guerra, Mateus Lima
* \date Jun 14, 2010
*/
#include <Arduino.h>
#include "IEEE11073float.h"
uint32_t float2IEEE11073(double data, uint8_t output[4])
{
uint32_t result = MDER_NaN;
if (isnan(data)) {
goto finally;
}/* else if (data > MDER_FLOAT_MAX) {
result = MDER_POSITIVE_INFINITY;
goto finally;
} else if (data < MDER_FLOAT_MIN) {
result = MDER_NEGATIVE_INFINITY;
goto finally;
} else if (data >= -MDER_FLOAT_EPSILON &&
data <= MDER_FLOAT_EPSILON) {
result = 0;
goto finally;
}*/
double sgn; sgn = data > 0 ? +1 : -1;
double mantissa; mantissa = fabs(data);
int32_t exponent; exponent = 0; // Note: 10**x exponent, not 2**x
// scale up if number is too big
while (mantissa > MDER_FLOAT_MANTISSA_MAX) {
mantissa /= 10.0;
++exponent;
if (exponent > MDER_FLOAT_EXPONENT_MAX) {
// argh, should not happen
if (sgn > 0) {
result = MDER_POSITIVE_INFINITY;
} else {
result = MDER_NEGATIVE_INFINITY;
}
goto finally;
}
}
// scale down if number is too small
while (mantissa < 1) {
mantissa *= 10;
--exponent;
if (exponent < MDER_FLOAT_EXPONENT_MIN) {
// argh, should not happen
result = 0;
goto finally;
}
}
// scale down if number needs more precision
double smantissa; smantissa = round(mantissa * MDER_FLOAT_PRECISION);
double rmantissa; rmantissa = round(mantissa) * MDER_FLOAT_PRECISION;
double mdiff; mdiff = abs(smantissa - rmantissa);
while (mdiff > 0.5 && exponent > MDER_FLOAT_EXPONENT_MIN &&
(mantissa * 10) <= MDER_FLOAT_MANTISSA_MAX) {
mantissa *= 10;
--exponent;
smantissa = round(mantissa * MDER_FLOAT_PRECISION);
rmantissa = round(mantissa) * MDER_FLOAT_PRECISION;
mdiff = abs(smantissa - rmantissa);
}
uint32_t int_mantissa; int_mantissa = (int) round(sgn * mantissa);
result = (exponent << 24) | (int_mantissa & 0xFFFFFF);
finally:
if ( output ) memcpy(output, &result, 4);
return result;
}
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