/*************************************************************************
*									 *
*	 YAP Prolog   %W% %G%
*									 *
*	Yap Prolog was developed at NCCUP - Universidade do Porto	 *
*									 *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997	 *
*									 *
**************************************************************************
*									 *
* File:		Atoms.h.m4						 *
* Last rev:	19/2/88							 *
* mods:									 *
* comments:	atom properties header file for YAP			 *
*									 *
*************************************************************************/

#ifndef ATOMS_H
#define ATOMS_H 1

#ifndef EXTERN
#ifndef ADTDEFS_C
#define EXTERN  static
#else
#define EXTERN
#endif
#endif

#include <wchar.h>

typedef    struct atom_blob {
  size_t length;
  char data[MIN_ARRAY];
} atom_blob_t;

/*********  operations for atoms ****************************************/

/*    Atoms are assumed to be uniquely represented by an OFFSET and to have
    associated with them a struct of type AtomEntry
    The	two functions
	RepAtom	: Atom -> *AtomEntry
	AbsAtom	: *AtomEntry ->	Atom
    are used to encapsulate the implementation of atoms
*/

typedef struct AtomEntryStruct *Atom;
typedef struct PropEntryStruct *Prop;


/* I can only define the structure after I define the actual atoms */

/*		 atom structure						*/
typedef struct AtomEntryStruct
{
  Atom NextOfAE;		/* used to build hash chains                    */
  Prop PropsOfAE;		/* property list for this atom                  */
#if defined(YAPOR) || defined(THREADS)
  rwlock_t ARWLock;
#endif

  union {
    char uStrOfAE[MIN_ARRAY];	/* representation of atom as a string           */
    wchar_t uWStrOfAE[MIN_ARRAY];	/* representation of atom as a string           */
    struct atom_blob blob[MIN_ARRAY];
  } rep;
}
AtomEntry;

// compatible with C and C++;
typedef struct ExtraAtomEntryStruct
{
  Atom NextOfAE;                /* used to build hash chains                    */
  Prop PropsOfAE;               /* property list for this atom                  */
#if defined(YAPOR) || defined(THREADS)
  rwlock_t ARWLock;
#endif

  union {
    char uStrOfAE[4];   /* representation of atom as a string           */
    wchar_t uWStrOfAE[2];       /* representation of atom as a string           */
    struct atom_blob blob[2];
  } rep;
}
  ExtraAtomEntry;

#define StrOfAE rep.uStrOfAE
#define WStrOfAE rep.uWStrOfAE


/* Props and Atoms are stored in chains, ending with a NIL */
#ifdef USE_OFFSETS
#	define EndOfPAEntr(P)	( Addr(P) == AtomBase)
#else
#	define EndOfPAEntr(P)	( Addr(P) == NIL )
#endif

#define AtomName(at)	RepAtom(at)->StrOfAE


/* ********************** Properties  **********************************/

#if defined(USE_OFFSETS)
#define USE_OFFSETS_IN_PROPS 1
#else
#define USE_OFFSETS_IN_PROPS 0
#endif

typedef SFLAGS PropFlags;

/*	    basic property entry structure				*/
typedef struct PropEntryStruct
{
  Prop NextOfPE;		/* used to chain properties                     */
  PropFlags KindOfPE;		/* kind of property                             */
} PropEntry;

/* ************************* Functors  **********************************/

     /*         Functor data type
        abstype Functor =       atom # int
        with MkFunctor(a,n) = ...
        and  NameOfFunctor(f) = ...
        and  ArityOfFunctor(f) = ...                                    */

#define	MaxArity	    255

typedef CELL arity_t;

    #define FunctorProperty   ((PropFlags)(0xbb00))

/* functor property */
typedef struct FunctorEntryStruct
{
  Prop NextOfPE;		/* used to chain properties     */
  PropFlags KindOfPE;		/* kind of property             */
  arity_t ArityOfFE;	/* arity of functor             */
  Atom NameOfFE;		/* back pointer to owner atom   */
  Prop PropsOfFE;		/* pointer to list of properties for this functor */
#if defined(YAPOR) || defined(THREADS)
  rwlock_t FRWLock;
#endif
} FunctorEntry;

typedef FunctorEntry *Functor;

#endif /* ATOMS_H */