Colony » Colony Scout

/*-

 * Copyright (c) 1990, 1993

 *        The Regents of the University of California.  All rights reserved.

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 * 1. Redistributions of source code must retain the above copyright

 *    notice, this list of conditions and the following disclaimer.

 * 2. Redistributions in binary form must reproduce the above copyright

 *    notice, this list of conditions and the following disclaimer in the

 *    documentation and/or other materials provided with the distribution.

 * 3. Neither the name of the University nor the names of its contributors

 *    may be used to endorse or promote products derived from this software

 *    without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND

 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE

 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE

 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE

 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL

 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS

 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)

 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT

 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY

 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF

 * SUCH DAMAGE.

 */

#include <limits.h>

#include <ctype.h>

#include <errno.h>

#include <stdlib.h>

/*

 * Convert a string to a long integer.

 *

 * Ignores `locale' stuff.  Assumes that the upper and lower case

 * alphabets and digits are each contiguous.

 */

long

strtol(nptr, endptr, base)

        const char *nptr;

        char **endptr;

        int base;

{

        const char *s;

        long acc, cutoff;

        int c;

        int neg, any, cutlim;

        /*

         * Skip white space and pick up leading +/- sign if any.

         * If base is 0, allow 0x for hex and 0 for octal, else

         * assume decimal; if base is already 16, allow 0x.

         */

        s = nptr;

        do {

                c = (unsigned char) *s++;

        } while (isspace(c));

        if (c == '-') {

                neg = 1;

                c = *s++;

        } else {

                neg = 0;

                if (c == '+')

                        c = *s++;

        }

        if ((base == 0 || base == 16) &&

            c == '0' && (*s == 'x' || *s == 'X')) {

                c = s[1];

                s += 2;

                base = 16;

        }

        if (base == 0)

                base = c == '0' ? 8 : 10;

        /*

         * Compute the cutoff value between legal numbers and illegal

         * numbers.  That is the largest legal value, divided by the

         * base.  An input number that is greater than this value, if

         * followed by a legal input character, is too big.  One that

         * is equal to this value may be valid or not; the limit

         * between valid and invalid numbers is then based on the last

         * digit.  For instance, if the range for longs is

         * [-2147483648..2147483647] and the input base is 10,

         * cutoff will be set to 214748364 and cutlim to either

         * 7 (neg==0) or 8 (neg==1), meaning that if we have accumulated

         * a value > 214748364, or equal but the next digit is > 7 (or 8),

         * the number is too big, and we will return a range error.

         *

         * Set any if any `digits' consumed; make it negative to indicate

         * overflow.

         */

        cutoff = neg ? LONG_MIN : LONG_MAX;

        cutlim = (int)(cutoff % base);

        cutoff /= base;

        if (neg) {

                if (cutlim > 0) {

                        cutlim -= base;

                        cutoff += 1;

                }

                cutlim = -cutlim;

        }

        for (acc = 0, any = 0;; c = (unsigned char) *s++) {

                if (isdigit(c))

                        c -= '0';

                else if (isalpha(c))

                        c -= isupper(c) ? 'A' - 10 : 'a' - 10;

                else

                        break;

                if (c >= base)

                        break;

                if (any < 0)

                        continue;

                if (neg) {

                        if (acc < cutoff || (acc == cutoff && c > cutlim)) {

                                any = -1;

                                acc = LONG_MIN;

                                errno = ERANGE;

                        } else {

                                any = 1;

                                acc *= base;

                                acc -= c;

                        }

                } else {

                        if (acc > cutoff || (acc == cutoff && c > cutlim)) {

                                any = -1;

                                acc = LONG_MAX;

                                errno = ERANGE;

                        } else {

                                any = 1;

                                acc *= base;

                                acc += c;

                        }

                }

        }

        if (endptr != 0)

                /* LINTED interface specification */

                *endptr = (char *)(any ? s - 1 : nptr);

        return (acc);

}