#ifndef SHSTR_H__
#define SHSTR_H__

#include <sstream>

#include "util.h"

extern int buf_overflow (const char *buf1, const char *buf2, int bufsize);

struct shstr
{
  static const char *null;

  const char *s;

  static int &refcnt (const char *s)
  {
    return *((int *)s - 1);
  }

  static int &length (const char *s)
  {
    return *((int *)s - 2);
  }

  int &refcnt () const
  {
    return refcnt (s);
  }

  int length () const
  {
    return length (s);
  }

  static const char *find (const char *s);
  static const char *intern (const char *s);

  static void gc (); // garbage collect a few strings

  // this is used for informational messages and the like
  const char *operator &() const { return s; }

  const char &operator [](int i) const { return s[i]; }
  operator const char *() const { return s == null ? 0 : s; }

  shstr ()
  : s (null)
  {
  }

  shstr (const shstr &sh)
  : s (sh.s)
  {
    ++refcnt ();
  }

  explicit shstr (const char *s)
  : s (intern (s))
  {
  }

  ~shstr ()
  {
    --refcnt ();
  }

  const shstr &operator =(const shstr &sh)
  {
    --refcnt ();
    s = sh.s;
    ++refcnt ();

    return *this;
  }

  const shstr &operator =(const char *str)
  {
    --refcnt ();

    // this optimises the important case of str == constant 0
    if (is_constant (str))
      s = str ? intern (str) : null;
    else
      s = intern (str);

    return *this;
  }

  bool operator ==(const shstr &b)
  {
    return s == b.s;
  }

  bool operator !=(const shstr &b)
  {
    return !(*this == b);
  }
};

inline int strlen (const shstr &sh)
{
  return sh.length ();
}

inline int strcmp (const shstr &a, const shstr &b)
{
  // TODO: use this to find all the occurences of people using strcmp
  // all uses should be bogus, as we should be never interested in
  // comparing shstr's alphabetically
#if 0
  extern void do_not_use_strcmp_to_compare_shstr_values ();
  do_not_use_strcmp_to_compare_shstr_values ();
#endif
  return a != b;
}

std::ostream &operator <<(std::ostream &o, const shstr &sh)
{
  o.write (sh.s, sh.length ());
  return o;
}

// only good for mass comparisons to shstr objects
struct shstr_cmp
{
  const char *s;

  explicit shstr_cmp (const char *s)
  : s (shstr::find (s))
  {
  }

  shstr_cmp (const shstr_cmp &sh)
  : s (sh.s)
  {
  }

  shstr_cmp &operator =(const shstr_cmp sh) { s = sh.s; return *this; }
  operator const char *() const { return s; }
};

inline bool operator ==(const shstr_cmp &a, const shstr &b)
{
  return a.s == b.s;
}

inline bool operator ==(const shstr &a, const shstr_cmp &b)
{
  return b == a;
}

extern const shstr undead_name;	/* Used in hit_player() in main.c */

#endif