text: /* $OpenBSD: ap_strtol.c,v 1.7 2005/06/20 12:23:22 robert Exp $ */
  
  /* ====================================================================
   * The Apache Software License, Version 1.1
   *
   * Copyright (c) 2000-2003 The Apache Software Foundation.  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. The end-user documentation included with the redistribution,
   *    if any, must include the following acknowledgment:
   *       "This product includes software developed by the
   *        Apache Software Foundation (http://www.apache.org/)."
   *    Alternately, this acknowledgment may appear in the software itself,
   *    if and wherever such third-party acknowledgments normally appear.
   *
   * 4. The names "Apache" and "Apache Software Foundation" must
   *    not be used to endorse or promote products derived from this
   *    software without prior written permission. For written
   *    permission, please contact apache@apache.org.
   *
   * 5. Products derived from this software may not be called "Apache",
   *    nor may "Apache" appear in their name, without prior written
   *    permission of the Apache Software Foundation.
   *
   * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED 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 APACHE SOFTWARE FOUNDATION OR
   * ITS 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.
   * ====================================================================
   *
   * This software consists of voluntary contributions made by many
   * individuals on behalf of the Apache Software Foundation.  For more
   * information on the Apache Software Foundation, please see
   * <http://www.apache.org/>.
   *
   * Portions of this software are based upon public domain software
   * originally written at the National Center for Supercomputing Applications,
   * University of Illinois, Urbana-Champaign.
   */
  /*-
   * 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 "httpd.h"
  #include <limits.h>
  #include <errno.h>
  #include <stdlib.h>
  #include "ap_ctype.h"
  
  #ifndef LONG_MAX
  #define LONG_MAX  2147483647
  #endif
  #ifndef LONG_MIN
  #define LONG_MIN  (-2147483647-1)
  #endif
  
  /*
   * Convert a string to a long integer.
   *
   * Assumes that the upper and lower case
   * alphabets and digits are each contiguous.
   * (On EBCDIC machines it assumes that digits and
   *  upper/lower case A-I, J-R, and S-Z are contiguous.)
   */
  
  API_EXPORT(long)
  ap_strtol(const char *nptr, char **endptr, int base)
  {
  	const char *s;
  	unsigned long acc;
  	char c;
  	unsigned long cutoff;
  	int neg, any, cutlim;
          long result;
  
  	/*
  	 * 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 = *s++;
  	}
  	while (ap_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;
  	acc = any = 0;
  	if (base < 2 || base > 36)
  		goto noconv;
  
  	/*
  	 * 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) + LONG_MAX
  	    : LONG_MAX;
  	cutlim = cutoff % base;
  	cutoff /= base;
  	for ( ; ; c = *s++) {
  		if (c >= '0' && c <= '9')
  			c -= '0';
  		else if (c >= 'A' && c <= 'Z')
  			c -= 'A' - 10;
  		else if (c >= 'a' && c <= 'z')
  			c -= '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;
  		}
  	}
          result = (long)acc;
  	if (any < 0) {
  		result = neg ? LONG_MIN : LONG_MAX;
  		errno = ERANGE;
  	} else if (!any) {
  noconv:
                  result = (long)acc;
  		errno = EINVAL;
  	} else if (neg)
  		result = -(long)acc;
  	if (endptr != NULL)
  		*endptr = (char *)(any ? s - 1 : nptr);
  	return (result);
  }
  
  