xnu-344.34.tar.gz

[apple/xnu.git] / bsd / libkern / strtol.c

/*
 * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
 *
 * @APPLE_LICENSE_HEADER_START@
 * 
 * The contents of this file constitute Original Code as defined in and
 * are subject to the Apple Public Source License Version 1.1 (the
 * "License").  You may not use this file except in compliance with the
 * License.  Please obtain a copy of the License at
 * http://www.apple.com/publicsource and read it before using this file.
 * 
 * This Original Code and all software distributed under the License are
 * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
 * License for the specific language governing rights and limitations
 * under the License.
 * 
 * @APPLE_LICENSE_HEADER_END@
 */
/*      Copyright (c) 1995 NeXT Computer, Inc.  All rights reserved.
 *
 * strol.c - The functions strtol() & strtoul() are exported as public API
 *           via the header file ~driverkit/generalFuncs.h
 *
 * HISTORY
 * 25-Oct-1995    Dean Reece at NeXT
 *      Created based on BSD4.4's strtol.c & strtoul.c.
 *      Removed dependency on _ctype_ by static versions of isupper()...
 *      Added support for "0b101..." binary constants.
 *      Commented out references to errno.
 */

/*-
 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *	This product includes software developed by the University of
 *	California, Berkeley and its contributors.
 * 4. 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.
 */


static inline int
isupper(char c)
{
    return (c >= 'A' && c <= 'Z');
}

static inline int
isalpha(char c)
{
    return ((c >= 'A' && c <= 'Z') || (c >= 'a' && c <= 'z'));
}


static inline int
isspace(char c)
{
    return (c == ' ' || c == '\t' || c == '\n' || c == '\12');
}

static inline int
isdigit(char c)
{
    return (c >= '0' && c <= '9');
}

/*
 * 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;
	register int base;
{
	register const char *s = nptr;
	register unsigned long acc;
	register int c;
	register unsigned long cutoff;
	register int neg = 0, 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.
	 */
	do {
		c = *s++;
	} while (isspace(c));
	if (c == '-') {
		neg = 1;
		c = *s++;
	} else if (c == '+')
		c = *s++;
	if ((base == 0 || base == 16) &&
	    c == '0' && (*s == 'x' || *s == 'X')) {
		c = s[1];
		s += 2;
		base = 16;
	} else if ((base == 0 || base == 2) &&
	    c == '0' && (*s == 'b' || *s == 'B')) {
		c = s[1];
		s += 2;
		base = 2;
	}
	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 ? -(unsigned long)LONG_MIN : LONG_MAX;
	cutlim = cutoff % (unsigned long)base;
	cutoff /= (unsigned long)base;
	for (acc = 0, any = 0;; c = *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 || acc > cutoff || acc == cutoff && c > cutlim)
			any = -1;
		else {
			any = 1;
			acc *= base;
			acc += c;
		}
	}
	if (any < 0) {
		acc = neg ? LONG_MIN : LONG_MAX;
//		errno = ERANGE;
	} else if (neg)
		acc = -acc;
	if (endptr != 0)
		*endptr = (char *)(any ? s - 1 : nptr);
	return (acc);
}

/*
 * Convert a string to an unsigned long integer.
 *
 * Ignores `locale' stuff.  Assumes that the upper and lower case
 * alphabets and digits are each contiguous.
 */
unsigned long
strtoul(nptr, endptr, base)
	const char *nptr;
	char **endptr;
	register int base;
{
	register const char *s = nptr;
	register unsigned long acc;
	register int c;
	register unsigned long cutoff;
	register int neg = 0, any, cutlim;

	/*
	 * See strtol for comments as to the logic used.
	 */
	do {
		c = *s++;
	} while (isspace(c));
	if (c == '-') {
		neg = 1;
		c = *s++;
	} else if (c == '+')
		c = *s++;
	if ((base == 0 || base == 16) &&
	    c == '0' && (*s == 'x' || *s == 'X')) {
		c = s[1];
		s += 2;
		base = 16;
	} else if ((base == 0 || base == 2) &&
	    c == '0' && (*s == 'b' || *s == 'B')) {
		c = s[1];
		s += 2;
		base = 2;
	}
	if (base == 0)
		base = c == '0' ? 8 : 10;
	cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;
	cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;
	for (acc = 0, any = 0;; c = *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 || acc > cutoff || acc == cutoff && c > cutlim)
			any = -1;
		else {
			any = 1;
			acc *= base;
			acc += c;
		}
	}
	if (any < 0) {
		acc = ULONG_MAX;
//		errno = ERANGE;
	} else if (neg)
		acc = -acc;
	if (endptr != 0)
		*endptr = (char *)(any ? s - 1 : nptr);
	return (acc);
}