/*-
 * Copyright (c) 2002-2018 The UbixOS Project.
 * All rights reserved.
 *
 * This was developed by Christopher W. Olsen for the UbixOS Project.
 *
 * 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, the following disclaimer and the list of authors.
 * 2) Redistributions in binary form must reproduce the above copyright notice, this list of
 *    conditions, the following disclaimer and the list of authors in the documentation and/or
 *    other materials provided with the distribution.
 * 3) Neither the name of the UbixOS Project 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 AUTHOR 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 COPYRIGHT OWNER 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 <sys/cdefs.h>
//#include <limits.h>
//#include <ctype.h>
//#include <stdlib.h>

#define LONG_MIN      (-0x7fffffffL - 1)
#define LONG_MAX      0x7fffffffL

long strtol(const char * __restrict nptr, char ** __restrict endptr, int base) {
  const char *s;
  unsigned long acc;
  char c = 0x0; /* to remove warning */
  unsigned long cutoff;
  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 = *s++;
   } while (isspace((unsigned char)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;
    }
  }
  if (any < 0) {
    acc = neg ? LONG_MIN : LONG_MAX;
    //errno = ERANGE;
  }
  else if (!any) {
    noconv:
    //errno = EINVAL;
    cutoff = 0x0; //UBU
  }
  else if (neg)
    acc = -acc;
  if (endptr != 0x0)
    *endptr = (char *) (any ? s - 1 : nptr);
  return (acc);
}