common/util/strtol.c

	strtol.c revision 7257d1b4d25bfac0c802847390e98a464fd787ac
/*
 * CDDL HEADER START
 *
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License (the "License").
 * You may not use this file except in compliance with the License.
 *
 * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE
 * or http://www.opensolaris.org/os/licensing.
 * See the License for the specific language governing permissions
 * and limitations under the License.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file at usr/src/OPENSOLARIS.LICENSE.
 * If applicable, add the following below this CDDL HEADER, with the
 * fields enclosed by brackets "[]" replaced with your own identifying
 * information: Portions Copyright [yyyy] [name of copyright owner]
 *
 * CDDL HEADER END
 */

/*
 * Copyright 2008 Sun Microsystems, Inc.  All rights reserved.
 * Use is subject to license terms.
 */

/*  Copyright (c) 1988 AT&T */
/*    All Rights Reserved   */

#pragma ident   "%Z%%M% %I% %E% SMI"

#if !defined(_BOOT) && !defined(_KMDB)
#include "lint.h"
#endif /* !_BOOT && !_KMDB */
#include <errno.h>
#include <ctype.h>
#include <limits.h>
#include <sys/types.h>
#include <stdlib.h>

#define DIGIT(x)    \
    (isdigit(x) ? (x) - '0' : islower(x) ? (x) + 10 - 'a' : (x) + 10 - 'A')

#define MBASE   ('z' - 'a' + 1 + 10)

/*
 * The following macro is a local version of isalnum() which limits
 * alphabetic characters to the ranges a-z and A-Z; locale dependent
 * characters will not return 1. The members of a-z and A-Z are
 * assumed to be in ascending order and contiguous
 */
#define lisalnum(x) \
    (isdigit(x) || ((x) >= 'a' && (x) <= 'z') || ((x) >= 'A' && (x) <= 'Z'))

long
strtol(const char *str, char **nptr, int base)
{
    long val;
    int c;
    int xx, neg = 0;
    long    multmin;
    long    limit;
    const char **ptr = (const char **)nptr;
    const unsigned char *ustr = (const unsigned char *)str;

    if (ptr != (const char **)0)
        *ptr = (char *)ustr; /* in case no number is formed */
    if (base < 0 || base > MBASE || base == 1) {
        errno = EINVAL;
        return (0); /* base is invalid -- should be a fatal error */
    }
    if (!isalnum(c = *ustr)) {
        while (isspace(c))
            c = *++ustr;
        switch (c) {
        case '-':
            neg++;
            /* FALLTHROUGH */
        case '+':
            c = *++ustr;
        }
    }
    if (base == 0)
        if (c != '0')
            base = 10;
        else if (ustr[1] == 'x' || ustr[1] == 'X')
            base = 16;
        else
            base = 8;
    /*
     * for any base > 10, the digits incrementally following
     *  9 are assumed to be "abc...z" or "ABC...Z"
     */
    if (!lisalnum(c) || (xx = DIGIT(c)) >= base)
        return (0); /* no number formed */
    if (base == 16 && c == '0' && (ustr[1] == 'x' || ustr[1] == 'X') &&
        isxdigit(ustr[2]))
        c = *(ustr += 2); /* skip over leading "0x" or "0X" */

    /* this code assumes that abs(LONG_MIN) >= abs(LONG_MAX) */
    if (neg)
        limit = LONG_MIN;
    else
        limit = -LONG_MAX;
    multmin = limit / (long)base;
    val = -DIGIT(c);
    for (c = *++ustr; lisalnum(c) && (xx = DIGIT(c)) < base; ) {
        /* accumulate neg avoids surprises near MAXLONG */
        if (val < multmin)
            goto overflow;
        val *= base;
        if (val < limit + xx)
            goto overflow;
        val -= xx;
        c = *++ustr;
    }
    if (ptr != (const char **)0)
        *ptr = (char *)ustr;
    return (neg ? val : -val);

overflow:
    for (c = *++ustr; lisalnum(c) && (xx = DIGIT(c)) < base; (c = *++ustr))
        ;
    if (ptr != (const char **)0)
        *ptr = (char *)ustr;
    errno = ERANGE;
    return (neg ? LONG_MIN : LONG_MAX);
}