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glibc  2.9
s_llround.c
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00001 /* Round double value to long long int.
00002    Copyright (C) 1997 Free Software Foundation, Inc.
00003    This file is part of the GNU C Library.
00004 
00005    The GNU C Library is free software; you can redistribute it and/or
00006    modify it under the terms of the GNU Lesser General Public
00007    License as published by the Free Software Foundation; either
00008    version 2.1 of the License, or (at your option) any later version.
00009 
00010    The GNU C Library is distributed in the hope that it will be useful,
00011    but WITHOUT ANY WARRANTY; without even the implied warranty of
00012    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00013    Lesser General Public License for more details.
00014 
00015    You should have received a copy of the GNU Lesser General Public
00016    License along with the GNU C Library; if not, write to the Free
00017    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00018    02111-1307 USA.  */
00019 
00020 #include <math.h>
00021 
00022 /* I think that what this routine is supposed to do is round a value
00023    to the nearest integer, with values exactly on the boundary rounded
00024    away from zero.  */
00025 /* This routine relies on (long long)x, when x is out of range of a long long,
00026    clipping to MAX_LLONG or MIN_LLONG.  */
00027 
00028 long long int
00029 __llround (double x)
00030 {
00031   double xrf;
00032   long long int xr;
00033   xr = (long long int) x;
00034   xrf = (double) xr;
00035   if (x >= 0.0)
00036     if (x - xrf >= 0.5 && x - xrf < 1.0 && x+1 > 0)
00037       return x+1;
00038     else
00039       return x;
00040   else
00041     if (xrf - x >= 0.5 && xrf - x < 1.0 && x-1 < 0)
00042       return x-1;
00043     else
00044       return x;
00045 }
00046 weak_alias (__llround, llround)
00047 #ifdef NO_LONG_DOUBLE
00048 strong_alias (__llround, __llroundl)
00049 weak_alias (__llround, llroundl)
00050 #endif