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glibc  2.9
uitrunc.c
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00001 /* Copyright (C) 2000 Free Software Foundation, Inc.
00002    This file is part of the GNU C Library.
00003 
00004    The GNU C Library is free software; you can redistribute it and/or
00005    modify it under the terms of the GNU Lesser General Public
00006    License as published by the Free Software Foundation; either
00007    version 2.1 of the License, or (at your option) any later version.
00008 
00009    The GNU C Library is distributed in the hope that it will be useful,
00010    but WITHOUT ANY WARRANTY; without even the implied warranty of
00011    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
00012    Lesser General Public License for more details.
00013 
00014    You should have received a copy of the GNU Lesser General Public
00015    License along with the GNU C Library; if not, write to the Free
00016    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
00017    02111-1307 USA.  */
00018 
00019 #include <math.h>
00020 
00021 /* The uitrunc function returns the nearest unsigned integer
00022    to the x parameter in the direction of 0. This actions is
00023    equivalent to truncation off the fraction bits of the x
00024    parameter and then converting x to an unsigned integer. */
00025 unsigned int
00026 __uitrunc (double x)
00027 {
00028   double xrf;
00029   unsigned int xr;
00030   xr = (unsigned int) x;
00031   xrf = (double) xr;
00032   if (x >= 0.0)
00033     if (x - xrf >= 0.5 && x - xrf < 1.0 && x + 1 > 0)
00034       return x + 1;
00035     else
00036       return x;
00037   else
00038     if (xrf - x >= 0.5 && xrf - x < 1.0 && x - 1 < 0)
00039       return x - 1;
00040     else
00041       return x;
00042 }