#include "Python.h"

#if defined(__sgi) && defined(WITH_THREAD) && !defined(_SGI_MP_SOURCE)
#define _SGI_MP_SOURCE
#endif

/* Convert a possibly signed character to a nonnegative int */
/* XXX This assumes characters are 8 bits wide */
#ifdef __CHAR_UNSIGNED__
#define Py_CHARMASK(c)          (c)
#else
#define Py_CHARMASK(c)          ((c) & 0xff)
#endif

/* strtol and strtoul, renamed to avoid conflicts */


#include <ctype.h>
#ifdef HAVE_ERRNO_H
#include <errno.h>
#endif

/* Static overflow check values for bases 2 through 36.
* smallmax[base] is the largest unsigned long i such that
* i * base doesn't overflow unsigned long.
*/
static unsigned long smallmax[] = {
       0, /* bases 0 and 1 are invalid */
       0,
       ULONG_MAX / 2,
       ULONG_MAX / 3,
       ULONG_MAX / 4,
       ULONG_MAX / 5,
       ULONG_MAX / 6,
       ULONG_MAX / 7,
       ULONG_MAX / 8,
       ULONG_MAX / 9,
       ULONG_MAX / 10,
       ULONG_MAX / 11,
       ULONG_MAX / 12,
       ULONG_MAX / 13,
       ULONG_MAX / 14,
       ULONG_MAX / 15,
       ULONG_MAX / 16,
       ULONG_MAX / 17,
       ULONG_MAX / 18,
       ULONG_MAX / 19,
       ULONG_MAX / 20,
       ULONG_MAX / 21,
       ULONG_MAX / 22,
       ULONG_MAX / 23,
       ULONG_MAX / 24,
       ULONG_MAX / 25,
       ULONG_MAX / 26,
       ULONG_MAX / 27,
       ULONG_MAX / 28,
       ULONG_MAX / 29,
       ULONG_MAX / 30,
       ULONG_MAX / 31,
       ULONG_MAX / 32,
       ULONG_MAX / 33,
       ULONG_MAX / 34,
       ULONG_MAX / 35,
       ULONG_MAX / 36,
};

/* maximum digits that can't ever overflow for bases 2 through 36,
* calculated by [int(math.floor(math.log(2**32, i))) for i in range(2, 37)].
* Note that this is pessimistic if sizeof(long) > 4.
*/
#if SIZEOF_LONG == 4
static int digitlimit[] = {
       0,  0, 32, 20, 16, 13, 12, 11, 10, 10,  /*  0 -  9 */
       9,  9,  8,  8,  8,  8,  8,  7,  7,  7,  /* 10 - 19 */
       7,  7,  7,  7,  6,  6,  6,  6,  6,  6,  /* 20 - 29 */
       6,  6,  6,  6,  6,  6,  6};             /* 30 - 36 */
#elif SIZEOF_LONG == 8
/* [int(math.floor(math.log(2**64, i))) for i in range(2, 37)] */
static int digitlimit[] = {
        0,   0, 64, 40, 32, 27, 24, 22, 21, 20,  /*  0 -  9 */
       19,  18, 17, 17, 16, 16, 16, 15, 15, 15,  /* 10 - 19 */
       14,  14, 14, 14, 13, 13, 13, 13, 13, 13,  /* 20 - 29 */
       13,  12, 12, 12, 12, 12, 12};             /* 30 - 36 */
#else
#error "Need table for SIZEOF_LONG"
#endif

/*
**      strtoul
**              This is a general purpose routine for converting
**              an ascii string to an integer in an arbitrary base.
**              Leading white space is ignored.  If 'base' is zero
**              it looks for a leading 0, 0x or 0X to tell which
**              base.  If these are absent it defaults to 10.
**              Base must be 0 or between 2 and 36 (inclusive).
**              If 'ptr' is non-NULL it will contain a pointer to
**              the end of the scan.
**              Errors due to bad pointers will probably result in
**              exceptions - we don't check for them.
*/
unsigned long
PyOS_strtoul(register char *str, char **ptr, int base)
{
       register unsigned long result = 0; /* return value of the function */
       register int c;         /* current input character */
       register int ovlimit;   /* required digits to overflow */

       /* skip leading white space */
       while (*str && isspace(Py_CHARMASK(*str)))
               ++str;

       /* check for leading 0 or 0x for auto-base or base 16 */
       switch (base) {
               case 0:         /* look for leading 0, 0x or 0X */
                       if (*str == '0') {
                               ++str;
                               if (*str == 'x' || *str == 'X') {
                                       ++str;
                                       base = 16;
                               }
                               else
                                       base = 8;
                       }
                       else
                               base = 10;
                       break;

               case 16:        /* skip leading 0x or 0X */
                       if (*str == '0') {
                               ++str;
                               if (*str == 'x' || *str == 'X')
                                       ++str;
                       }
                       break;
       }

       /* catch silly bases */
       if (base < 2 || base > 36) {
               if (ptr)
                       *ptr = str;
               return 0;
       }

       /* skip leading zeroes */
       while (*str == '0')
               ++str;

       /* base is guaranteed to be in [2, 36] at this point */
       ovlimit = digitlimit[base];

       /* do the conversion until non-digit character encountered */
       while ((c = _PyLong_DigitValue[Py_CHARMASK(*str)]) < base) {
               if (ovlimit > 0) /* no overflow check required */
                       result = result * base + c;
               else { /* requires overflow check */
                       register unsigned long temp_result;

                       if (ovlimit < 0) /* guaranteed overflow */
                               goto overflowed;

                       /* there could be an overflow */
                       /* check overflow just from shifting */
                       if (result > smallmax[base])
                               goto overflowed;

                       result *= base;

                       /* check overflow from the digit's value */
                       temp_result = result + c;
                       if (temp_result < result)
                               goto overflowed;

                       result = temp_result;
               }

               ++str;
               --ovlimit;
       }

       /* set pointer to point to the last character scanned */
       if (ptr)
               *ptr = str;

       return result;

overflowed:
       if (ptr) {
               /* spool through remaining digit characters */
               while (_PyLong_DigitValue[Py_CHARMASK(*str)] < base)
                       ++str;
               *ptr = str;
       }
       errno = ERANGE;
       return (unsigned long)-1;
}

/* Checking for overflow in PyOS_strtol is a PITA; see comments
* about PY_ABS_LONG_MIN in longobject.c.
*/
#define PY_ABS_LONG_MIN         (0-(unsigned long)LONG_MIN)

long
PyOS_strtol(char *str, char **ptr, int base)
{
       long result;
       unsigned long uresult;
       char sign;

       while (*str && isspace(Py_CHARMASK(*str)))
               str++;

       sign = *str;
       if (sign == '+' || sign == '-')
               str++;

       uresult = PyOS_strtoul(str, ptr, base);

       if (uresult <= (unsigned long)LONG_MAX) {
               result = (long)uresult;
               if (sign == '-')
                       result = -result;
       }
       else if (sign == '-' && uresult == PY_ABS_LONG_MIN) {
               result = LONG_MIN;
       }
       else {
               errno = ERANGE;
               result = LONG_MAX;
       }
       return result;
}