#ifndef _LINUX_STRING_HELPERS_H_
  #define _LINUX_STRING_HELPERS_H_
  
  #include <linux/types.h>
  
  /* Descriptions of the types of units to
   * print in */
  enum string_size_units {
  	STRING_UNITS_10,	/* use powers of 10^3 (standard SI) */
  	STRING_UNITS_2,		/* use binary powers of 2^10 */
  };
  
  int string_get_size(u64 size, enum string_size_units units,
  		    char *buf, int len);
  
  #define UNESCAPE_SPACE		0x01
  #define UNESCAPE_OCTAL		0x02
  #define UNESCAPE_HEX		0x04
  #define UNESCAPE_SPECIAL	0x08
  #define UNESCAPE_ANY		\
  	(UNESCAPE_SPACE | UNESCAPE_OCTAL | UNESCAPE_HEX | UNESCAPE_SPECIAL)
  
  /**
   * string_unescape - unquote characters in the given string
   * @src:	source buffer (escaped)
   * @dst:	destination buffer (unescaped)
   * @size:	size of the destination buffer (0 to unlimit)
   * @flags:	combination of the flags (bitwise OR):
   *	%UNESCAPE_SPACE:
   *		'\f' - form feed
   *		'
  ' - new line
   *		'\r' - carriage return
   *		'\t' - horizontal tab
   *		'\v' - vertical tab
   *	%UNESCAPE_OCTAL:
   *		'\NNN' - byte with octal value NNN (1 to 3 digits)
   *	%UNESCAPE_HEX:
   *		'\xHH' - byte with hexadecimal value HH (1 to 2 digits)
   *	%UNESCAPE_SPECIAL:
   *		'\"' - double quote
   *		'\\' - backslash
   *		'\a' - alert (BEL)
   *		'\e' - escape
   *	%UNESCAPE_ANY:
   *		all previous together
   *
   * Returns amount of characters processed to the destination buffer excluding
   * trailing '\0'.
   *
   * Because the size of the output will be the same as or less than the size of
   * the input, the transformation may be performed in place.
   *
   * Caller must provide valid source and destination pointers. Be aware that
   * destination buffer will always be NULL-terminated. Source string must be
   * NULL-terminated as well.
   */
  int string_unescape(char *src, char *dst, size_t size, unsigned int flags);
  
  static inline int string_unescape_inplace(char *buf, unsigned int flags)
  {
  	return string_unescape(buf, buf, 0, flags);
  }
  
  static inline int string_unescape_any(char *src, char *dst, size_t size)
  {
  	return string_unescape(src, dst, size, UNESCAPE_ANY);
  }
  
  static inline int string_unescape_any_inplace(char *buf)
  {
  	return string_unescape_any(buf, buf, 0);
  }
  
  #endif