usr/src/lib/libc/stdlib/atoi.c

/*
 * Copyright (c) 1988 Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTIBILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#if defined(LIBC_SCCS) && !defined(lint)
static char sccsid[] = "@(#)atoi.c      5.3 (Berkeley) %G%";
#endif /* LIBC_SCCS and not lint */

#include <ctype.h>

atoi(ascii)
        register char *ascii;
{
        register int val;
        int negative = 0;

        for (; isascii(*ascii) && isspace(*ascii); ++ascii);
        if (*ascii == '+')
                ++ascii;
        else if (*ascii == '-') {
                ++ascii;
                negative = 1;
        }
        for (val = 0; isascii(*ascii) && isdigit(*ascii); ++ascii)
                val = val * 10 + *ascii - '0';
        return(negative ? -val : val);
}