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 "ctype.h"
  21
  22 int atoi (const char *str)
  23 {
  24     int value = 0;
  25     int sign = 1;
  26
  27     while (isspace(*str))
  28     {
  29         str++;
  30     }
  31
  32     if ('-' == *str)
  33     {
  34         sign = -1;
  35         str++;
  36     }
  37     else if ('+' == *str)
  38     {
  39         str++;
  40     }
  41
  42     while ('0' == *str)
  43     {
  44         str++;
  45     }
  46
  47     while (isdigit(*str))
  48     {
  49         value = (value * 10) + (*str - '0');
  50         str++;
  51     }
  52
  53     return value * sign;
  54 }