root/strtol.c

DEFINITIONS

1. strtol

/* 
 * strtol.c --
 *
 *      Source code for the "strtol" library procedure.
 *
 * Copyright 1988 Regents of the University of California
 * Permission to use, copy, modify, and distribute this
 * software and its documentation for any purpose and without
 * fee is hereby granted, provided that the above copyright
 * notice appear in all copies.  The University of California
 * makes no representations about the suitability of this
 * software for any purpose.  It is provided "as is" without
 * express or implied warranty.
 */

#ifndef lint
static char rcsid[] = "$Header: /sprite/src/lib/c/stdlib/RCS/strtol.c,v 1.4 89/03/22 00:47:30 rab Exp $ SPRITE (Berkeley)";
#endif /* not lint */

#include <stdlib.h>
#include <ctype.h>

 
/*
 *----------------------------------------------------------------------
 *
 * strtol --
 *
 *      Convert an ASCII string into an integer.
 *
 * Results:
 *      The return value is the integer equivalent of string.  If endPtr
 *      is non-NULL, then *endPtr is filled in with the character
 *      after the last one that was part of the integer.  If string
 *      doesn't contain a valid integer value, then zero is returned
 *      and *endPtr is set to string.
 *
 * Side effects:
 *      None.
 *
 *----------------------------------------------------------------------
 */

long int
strtol(string, endPtr, base)
    char *string;               /* String of ASCII digits, possibly
                                 * preceded by white space.  For bases
                                 * greater than 10, either lower- or
                                 * upper-case digits may be used.
                                 */
    char **endPtr;              /* Where to store address of terminating
                                 * character, or NULL. */
    int base;                   /* Base for conversion.  Must be less
                                 * than 37.  If 0, then the base is chosen
                                 * from the leading characters of string:
                                 * "0x" means hex, "0" means octal, anything
                                 * else means decimal.
                                 */
{
    register char *p;
    int result;

    /*
     * Skip any leading blanks.
     */

    p = string;
    while (isspace(*p)) {
        p += 1;
    }

    /*
     * Check for a sign.
     */

    if (*p == '-') {
        p += 1;
        result = -(strtoul(p, endPtr, base));
    } else {
        if (*p == '+') {
            p += 1;
        }
        result = strtoul(p, endPtr, base);
    }
    if ((result == 0) && (endPtr != 0) && (*endPtr == p)) {
        *endPtr = string;
    }
    return result;
}