/*
 * Mark ring package
 *
 * Copyright (c) 1993, 1995
 *      ONO Kouichi             onono@fuka.info.waseda.ac.jp
 * All rights reserved.
 */

#ifndef _MARKRING_H_
#define _MARKRING_H_

#ifndef BOOL
typedef char            BOOL; 
#endif
#ifndef TRUE
#define TRUE            (1)
#define FALSE           (0)
#endif

typedef unsigned short int      NUMBER;

typedef int             RING_ELEMENT;   /* contents of Ring */
#ifndef RINGSIZE
#define RINGSIZE        (16)
#endif /* RINGSIZE */
typedef short int       RING_LOCATION;  /* index of Ring */
#define ILLEGAL_LOCAT   (-1)            /* when location is illegal */
#define INITIAL_FRONT   (0)             /* front index */
#define INITIAL_REAR    (RINGSIZE-1)    /* rear index */

struct MarkRing {
  RING_ELEMENT    element[RINGSIZE];    /* Ring body */
  RING_LOCATION   front;        /* front     : index of first-in element */
  RING_LOCATION   rear;         /* rear      : index of last-in element */
};

typedef struct MarkRing MARKRING;

typedef RING_ELEMENT    LIST_ELEMENT;   /* contents of List */
#define LISTSIZE        (RINGSIZE)
typedef short int       LIST_LOCATION;  /* index of List */
#define INITIAL_LIST    (0)             /* initial position of List */

typedef LIST_ELEMENT    MARKLIST[LISTSIZE];

extern  void             MakeRingNull();
extern  MARKRING         *CreateNewRing();
extern  BOOL             EmptyRing();
extern  BOOL             ElementExistsHereInRing();
extern  BOOL             BetweenOnRing();
extern  BOOL             MemberOfRing();
extern  RING_LOCATION    LocationOfMemberInRing();
extern  RING_ELEMENT     RingTopElement();
extern  RING_ELEMENT     RingLastElement();
extern  NUMBER           NumberOfElementsInRing();
extern  void             PurgeOldElementFromRing();
extern  void             PurgeLastElementFromRing();
extern  void             PurgeElementHereFromRing();
extern  void             PurgeTheValueAllFromRing();
extern  void             AddElementToRing();
extern  void             InsertElementToRing();
extern  void             RotateRing();
extern  void             ReverseRotateRing();
extern  MARKRING         *CopyRing();
extern  MARKRING         *MakeRingUnique();
extern  int              RingElemCompare();
extern  MARKRING         *MakeRingSort();
extern  LIST_LOCATION    MakeListFromRing();

#define Ring_Next_Location(i)   ( ((i)+1) % RINGSIZE )
#define Ring_Prev_Location(i)   ( (i)==INITIAL_FRONT ? INITIAL_REAR : ((i)-1) )
#define Is_Next_In_Ring(i, j)           ( Ring_Next_Location(j)==(i) )
#define Is_Prev_In_Ring(i, j)           ( Ring_Prev_Location(j)==(i) )
#define Is_Empty_Location(front, rear)  ( Is_Next_In_Ring(front, rear) )

#endif  /* _MARKRING_H_ */