strtoul.c

打魔兽战网的都知道他是什么

/*
 * Copyright (C) 1999  Ross Combs ([e-mail])
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */
#include "common/setup_before.h"
#ifndef HAVE_STRTOUL

#include <ctype.h>
#include "strtoul.h"
#include "common/setup_after.h"


extern unsigned long strtoul(char const * str, char * * endptr, int base)
{
    unsigned long val;
    char symbolval;
    char * pos;
    
    if (!str)
	return 0; /* EINVAL */
    
    for (pos=(char *)str; *pos==' ' || *pos=='\t'; pos++);
    if (*pos=='-' || *pos=='+')
        pos++;
    if ((base==0 || base==16) && *pos=='0' && (*(pos+1)=='x' || *(pos+1)=='X'))
    {
	base = 16;
	pos += 2; /* skip 0x prefix */
    }
    else if ((base==0 || base==8) && *pos=='0')
	{
	    base = 8;
	    pos += 1;
	}
    else if (base==0)
    	{
    	    base = 10;	
    	}
    	
    if (base<2 || base>16) /* sorry, not complete emulation (should do up to 36) */
	return 0; /* EINVAL */
    
    val = 0;
    for (; *pos!='\0'; pos++)
    {
        val *= base;
	
	if (isxdigit(*pos))
	{
		symbolval = isdigit(*pos) ? *pos-'0' : tolower(*pos)-'a'+10;
		if (base>symbolval)
			val += symbolval;
		else
			break;
		
	}
    }
    
    if (endptr)
	*endptr = (void *)pos; /* avoid warning */
    
    return val;
}

#else
typedef int filenotempty; /* make ISO standard happy */
#endif