firmware/common/atoi.c

   1 /***************************************************************************
   2  *             __________               __   ___.
   3  *   Open      \______   \ ____   ____ |  | _\_ |__   _______  ___
   4  *   Source     |       _//  _ \_/ ___\|  |/ /| __ \ /  _ \  \/  /
   5  *   Jukebox    |    |   (  <_> )  \___|    < | \_\ (  <_> > <  <
   6  *   Firmware   |____|_  /\____/ \___  >__|_ \|___  /\____/__/\_ \
   7  *                     \/            \/     \/    \/            \/
   8  * $Id$
   9  *
  10  * Copyright (C) 2002 by Gary Czvitkovicz
  11  *
  12  * All files in this archive are subject to the GNU General Public License.
  13  * See the file COPYING in the source tree root for full license agreement.
  14  *
  15  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
  16  * KIND, either express or implied.
  17  *
  18  ****************************************************************************/
  19
  20 #include <stdlib.h>
  21 #include "ctype.h"
  22
  23 int atoi (const char *str)
  24 {
  25     int value = 0;
  26     int sign = 1;
  27
  28     while (isspace(*str))
  29     {
  30         str++;
  31     }
  32
  33     if ('-' == *str)
  34     {
  35         sign = -1;
  36         str++;
  37     }
  38     else if ('+' == *str)
  39     {
  40         str++;
  41     }
  42
  43     while ('0' == *str)
  44     {
  45         str++;
  46     }
  47
  48     while (isdigit(*str))
  49     {
  50         value = (value * 10) + (*str - '0');
  51         str++;
  52     }
  53
  54     return value * sign;
  55 }