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/************************************************************
* lib_rint.c
*
* Copyright (C) 2007 Gregory Nutt. All rights reserved.
* Author: Gregory Nutt <spudmonkey@racsa.co.cr>
*
* 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. Neither the name Gregory Nutt 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 COPYRIGHT HOLDERS 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
* COPYRIGHT OWNER 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.
*
************************************************************/
/************************************************************
* Compilation Switches
************************************************************/
/************************************************************
* Included Files
************************************************************/
#include <sys/types.h>
#include <stdlib.h>
/************************************************************
* Definitions
************************************************************/
/************************************************************
* Private Type Declarations
************************************************************/
/************************************************************
* Private Function Prototypes
************************************************************/
/**********************************************************
* Global Constant Data
**********************************************************/
/************************************************************
* Global Variables
************************************************************/
/**********************************************************
* Private Constant Data
**********************************************************/
/************************************************************
* Private Variables
************************************************************/
double rint(double x)
{
double retValue;
/* If the current rounding mode rounds toward negative
* infinity, rint() is identical to floor(). If the current
* rounding mode rounds toward positive infinity, rint() is
* identical to ceil(). */
#if ((defined(FP_ROUND_POSITIVE)) && (FP_ROUNDING_POSITIVE != 0))
retValue = ceil(x);
#elif ((defined(FP_ROUND_NEGATIVE)) && (FP_ROUNDING_NEGATIVE != 0))
retValue = floor(x);
#else
/* In the default rounding mode (round to nearest), rint(x) is the
* integer nearest x with the additional stipulation that if
* |rint(x)-x|=1/2, then rint(x) is even. */
long dwInteger = (long)x;
double fRemainder = x - (double)dwInteger;
if (x < 0.0) {
/* fRemainder should be in range 0 .. -1 */
if (fRemainder == -0.5)
dwInteger = ((dwInteger+1)&~1);
else if (fRemainder < -0.5) {
dwInteger--;
} /* end if */
} /* end if */
else {
/* fRemainder should be in range 0 .. 1 */
if (fRemainder == 0.5)
dwInteger = ((dwInteger+1)&~1);
else if (fRemainder > 0.5) {
dwInteger++;
} /* end if */
} /* end else */
retValue = (double)dwInteger;
#endif
return retValue;
}
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