/*
   * Convert integer string representation to an integer.
   * If an integer doesn't fit into specified type, -E is returned.
   *
   * Integer starts with optional sign.
   * kstrtou*() functions do not accept sign "-".
   *
   * Radix 0 means autodetection: leading "0x" implies radix 16,
   * leading "0" implies radix 8, otherwise radix is 10.
   * Autodetection hints work after optional sign, but not before.
   *
   * If -E is returned, result is not touched.
   */
  #include <linux/ctype.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/math64.h>

  #include <linux/export.h>

  #include <linux/types.h>

  #include <asm/uaccess.h>

  #include "kstrtox.h"

  const char *_parse_integer_fixup_radix(const char *s, unsigned int *base)

  {

  	if (*base == 0) {

  		if (s[0] == '0') {
  			if (_tolower(s[1]) == 'x' && isxdigit(s[2]))

  				*base = 16;

  			else

  				*base = 8;

  		} else

  			*base = 10;

  	}

  	if (*base == 16 && s[0] == '0' && _tolower(s[1]) == 'x')

  		s += 2;

  	return s;
  }
  
  /*
   * Convert non-negative integer string representation in explicitly given radix
   * to an integer.
   * Return number of characters consumed maybe or-ed with overflow bit.
   * If overflow occurs, result integer (incorrect) is still returned.
   *
   * Don't you dare use this function.
   */

  unsigned int _parse_integer(const char *s, unsigned int base, unsigned long long *p)

  {

  	unsigned long long res;

  	unsigned int rv;
  	int overflow;

  	res = 0;

  	rv = 0;
  	overflow = 0;

  	while (*s) {
  		unsigned int val;
  
  		if ('0' <= *s && *s <= '9')
  			val = *s - '0';
  		else if ('a' <= _tolower(*s) && _tolower(*s) <= 'f')
  			val = _tolower(*s) - 'a' + 10;

  		else

  			break;

  
  		if (val >= base)

  			break;

  		/*
  		 * Check for overflow only if we are within range of
  		 * it in the max base we support (16)
  		 */
  		if (unlikely(res & (~0ull << 60))) {
  			if (res > div_u64(ULLONG_MAX - val, base))
  				overflow = 1;
  		}
  		res = res * base + val;

  		rv++;

  		s++;
  	}

  	*p = res;

  	if (overflow)
  		rv |= KSTRTOX_OVERFLOW;
  	return rv;
  }
  
  static int _kstrtoull(const char *s, unsigned int base, unsigned long long *res)
  {
  	unsigned long long _res;
  	unsigned int rv;
  
  	s = _parse_integer_fixup_radix(s, &base);
  	rv = _parse_integer(s, base, &_res);
  	if (rv & KSTRTOX_OVERFLOW)
  		return -ERANGE;

  	if (rv == 0)
  		return -EINVAL;
  	s += rv;
  	if (*s == '
  ')
  		s++;
  	if (*s)

  		return -EINVAL;

  	*res = _res;

  	return 0;
  }

  /**
   * kstrtoull - convert a string to an unsigned long long
   * @s: The start of the string. The string must be null-terminated, and may also
   *  include a single newline before its terminating null. The first character
   *  may also be a plus sign, but not a minus sign.
   * @base: The number base to use. The maximum supported base is 16. If base is
   *  given as 0, then the base of the string is automatically detected with the
   *  conventional semantics - If it begins with 0x the number will be parsed as a
   *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
   *  parsed as an octal number. Otherwise it will be parsed as a decimal.
   * @res: Where to write the result of the conversion on success.
   *
   * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
   * Used as a replacement for the obsolete simple_strtoull. Return code must
   * be checked.
   */

  int kstrtoull(const char *s, unsigned int base, unsigned long long *res)
  {
  	if (s[0] == '+')
  		s++;
  	return _kstrtoull(s, base, res);
  }
  EXPORT_SYMBOL(kstrtoull);

  /**
   * kstrtoll - convert a string to a long long
   * @s: The start of the string. The string must be null-terminated, and may also
   *  include a single newline before its terminating null. The first character
   *  may also be a plus sign or a minus sign.
   * @base: The number base to use. The maximum supported base is 16. If base is
   *  given as 0, then the base of the string is automatically detected with the
   *  conventional semantics - If it begins with 0x the number will be parsed as a
   *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
   *  parsed as an octal number. Otherwise it will be parsed as a decimal.
   * @res: Where to write the result of the conversion on success.
   *
   * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
   * Used as a replacement for the obsolete simple_strtoull. Return code must
   * be checked.
   */

  int kstrtoll(const char *s, unsigned int base, long long *res)
  {
  	unsigned long long tmp;
  	int rv;
  
  	if (s[0] == '-') {
  		rv = _kstrtoull(s + 1, base, &tmp);
  		if (rv < 0)
  			return rv;
  		if ((long long)(-tmp) >= 0)
  			return -ERANGE;
  		*res = -tmp;
  	} else {
  		rv = kstrtoull(s, base, &tmp);
  		if (rv < 0)
  			return rv;
  		if ((long long)tmp < 0)
  			return -ERANGE;
  		*res = tmp;
  	}
  	return 0;
  }
  EXPORT_SYMBOL(kstrtoll);
  
  /* Internal, do not use. */
  int _kstrtoul(const char *s, unsigned int base, unsigned long *res)
  {
  	unsigned long long tmp;
  	int rv;
  
  	rv = kstrtoull(s, base, &tmp);
  	if (rv < 0)
  		return rv;
  	if (tmp != (unsigned long long)(unsigned long)tmp)
  		return -ERANGE;
  	*res = tmp;
  	return 0;
  }
  EXPORT_SYMBOL(_kstrtoul);
  
  /* Internal, do not use. */
  int _kstrtol(const char *s, unsigned int base, long *res)
  {
  	long long tmp;
  	int rv;
  
  	rv = kstrtoll(s, base, &tmp);
  	if (rv < 0)
  		return rv;
  	if (tmp != (long long)(long)tmp)
  		return -ERANGE;
  	*res = tmp;
  	return 0;
  }
  EXPORT_SYMBOL(_kstrtol);

  /**
   * kstrtouint - convert a string to an unsigned int
   * @s: The start of the string. The string must be null-terminated, and may also
   *  include a single newline before its terminating null. The first character
   *  may also be a plus sign, but not a minus sign.
   * @base: The number base to use. The maximum supported base is 16. If base is
   *  given as 0, then the base of the string is automatically detected with the
   *  conventional semantics - If it begins with 0x the number will be parsed as a
   *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
   *  parsed as an octal number. Otherwise it will be parsed as a decimal.
   * @res: Where to write the result of the conversion on success.
   *
   * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
   * Used as a replacement for the obsolete simple_strtoull. Return code must
   * be checked.
   */

  int kstrtouint(const char *s, unsigned int base, unsigned int *res)
  {
  	unsigned long long tmp;
  	int rv;
  
  	rv = kstrtoull(s, base, &tmp);
  	if (rv < 0)
  		return rv;
  	if (tmp != (unsigned long long)(unsigned int)tmp)
  		return -ERANGE;
  	*res = tmp;
  	return 0;
  }
  EXPORT_SYMBOL(kstrtouint);

  /**
   * kstrtoint - convert a string to an int
   * @s: The start of the string. The string must be null-terminated, and may also
   *  include a single newline before its terminating null. The first character
   *  may also be a plus sign or a minus sign.
   * @base: The number base to use. The maximum supported base is 16. If base is
   *  given as 0, then the base of the string is automatically detected with the
   *  conventional semantics - If it begins with 0x the number will be parsed as a
   *  hexadecimal (case insensitive), if it otherwise begins with 0, it will be
   *  parsed as an octal number. Otherwise it will be parsed as a decimal.
   * @res: Where to write the result of the conversion on success.
   *
   * Returns 0 on success, -ERANGE on overflow and -EINVAL on parsing error.
   * Used as a replacement for the obsolete simple_strtoull. Return code must
   * be checked.
   */

  int kstrtoint(const char *s, unsigned int base, int *res)
  {
  	long long tmp;
  	int rv;
  
  	rv = kstrtoll(s, base, &tmp);
  	if (rv < 0)
  		return rv;
  	if (tmp != (long long)(int)tmp)
  		return -ERANGE;
  	*res = tmp;
  	return 0;
  }
  EXPORT_SYMBOL(kstrtoint);
  
  int kstrtou16(const char *s, unsigned int base, u16 *res)
  {
  	unsigned long long tmp;
  	int rv;
  
  	rv = kstrtoull(s, base, &tmp);
  	if (rv < 0)
  		return rv;
  	if (tmp != (unsigned long long)(u16)tmp)
  		return -ERANGE;
  	*res = tmp;
  	return 0;
  }
  EXPORT_SYMBOL(kstrtou16);
  
  int kstrtos16(const char *s, unsigned int base, s16 *res)
  {
  	long long tmp;
  	int rv;
  
  	rv = kstrtoll(s, base, &tmp);
  	if (rv < 0)
  		return rv;
  	if (tmp != (long long)(s16)tmp)
  		return -ERANGE;
  	*res = tmp;
  	return 0;
  }
  EXPORT_SYMBOL(kstrtos16);
  
  int kstrtou8(const char *s, unsigned int base, u8 *res)
  {
  	unsigned long long tmp;
  	int rv;
  
  	rv = kstrtoull(s, base, &tmp);
  	if (rv < 0)
  		return rv;
  	if (tmp != (unsigned long long)(u8)tmp)
  		return -ERANGE;
  	*res = tmp;
  	return 0;
  }
  EXPORT_SYMBOL(kstrtou8);
  
  int kstrtos8(const char *s, unsigned int base, s8 *res)
  {
  	long long tmp;
  	int rv;
  
  	rv = kstrtoll(s, base, &tmp);
  	if (rv < 0)
  		return rv;
  	if (tmp != (long long)(s8)tmp)
  		return -ERANGE;
  	*res = tmp;
  	return 0;
  }
  EXPORT_SYMBOL(kstrtos8);

  
  #define kstrto_from_user(f, g, type)					\
  int f(const char __user *s, size_t count, unsigned int base, type *res)	\
  {									\
  	/* sign, base 2 representation, newline, terminator */		\
  	char buf[1 + sizeof(type) * 8 + 1 + 1];				\
  									\
  	count = min(count, sizeof(buf) - 1);				\
  	if (copy_from_user(buf, s, count))				\
  		return -EFAULT;						\
  	buf[count] = '\0';						\
  	return g(buf, base, res);					\
  }									\
  EXPORT_SYMBOL(f)
  
  kstrto_from_user(kstrtoull_from_user,	kstrtoull,	unsigned long long);
  kstrto_from_user(kstrtoll_from_user,	kstrtoll,	long long);
  kstrto_from_user(kstrtoul_from_user,	kstrtoul,	unsigned long);
  kstrto_from_user(kstrtol_from_user,	kstrtol,	long);
  kstrto_from_user(kstrtouint_from_user,	kstrtouint,	unsigned int);
  kstrto_from_user(kstrtoint_from_user,	kstrtoint,	int);
  kstrto_from_user(kstrtou16_from_user,	kstrtou16,	u16);
  kstrto_from_user(kstrtos16_from_user,	kstrtos16,	s16);
  kstrto_from_user(kstrtou8_from_user,	kstrtou8,	u8);
  kstrto_from_user(kstrtos8_from_user,	kstrtos8,	s8);