osprey/cygnus/libiberty/strtoul.c

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/*
 * Copyright (c) 1990 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. [rescinded 22 July 1999]
 * 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.
 */

#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#ifdef HAVE_LIMITS_H
#include <limits.h>
#endif
#ifdef HAVE_SYS_PARAM_H
#include <sys/param.h>
#endif
#include <errno.h>
#ifdef NEED_DECLARATION_ERRNO
extern int errno;
#endif
#if 0
#include <stdlib.h>
#endif
#include "ansidecl.h"
#include "safe-ctype.h"

#ifndef ULONG_MAX
#define ULONG_MAX ((unsigned long)(~0L))    /* 0xFFFFFFFF */
#endif

/*
 * 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;
  }
  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);
}

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