#ifndef SILINK_H
#define SILINK_H
/****************************************
*  Computer Algebra System SINGULAR     *
****************************************/
/* $Id: silink.h,v 1.9 1998-06-02 15:30:04 Singular Exp $ */
/*
* ABSTRACT: general interface to links
*/

#include "structs.h"

// extension links:
typedef BOOLEAN    (*slOpenProc)(si_link l, short flag);
typedef BOOLEAN    (*slWriteProc)(si_link l, leftv lv);
typedef BOOLEAN    (*slCloseProc)(si_link l);
typedef leftv      (*slReadProc)(si_link l);
typedef leftv      (*slRead2Proc)(si_link l, leftv a);
typedef BOOLEAN    (*slDumpProc)(si_link l);
typedef BOOLEAN    (*slGetDumpProc)(si_link l);
typedef char*      (*slStatusProc)(si_link l, char *request);

struct s_si_link_extension
{
  si_link_extension next;
  slOpenProc       Open;
  slCloseProc      Close;
  slReadProc       Read;
  slRead2Proc      Read2;
  slWriteProc      Write;
  slDumpProc       Dump;
  slGetDumpProc    GetDump;
  slStatusProc     Status;
  char             *type;
};

struct sip_link
{
  si_link_extension m; // methods
  char *mode;
  char *name;          // used for filename and/or further specs
  void *data;          // the link itself
  BITSET flags;        // 0=close open = 1: read = 2: write = 3
  short ref;           // reference counter
};

BOOLEAN slExtend(si_link_extension s);

// flags:
#define SI_LINK_CLOSE   0
#define SI_LINK_OPEN    1
#define SI_LINK_READ    2
#define SI_LINK_WRITE   4

// tests:
#define SI_LINK_CLOSE_P(l)  (!(l)->flags)
#define SI_LINK_OPEN_P(l)   ((l)->flags & SI_LINK_OPEN)
#define SI_LINK_W_OPEN_P(l) ((l)->flags &  SI_LINK_WRITE)
#define SI_LINK_R_OPEN_P(l) ((l)->flags &  SI_LINK_READ)
#define SI_LINK_RW_OPEN_P(l) (SI_LINK_W_OPEN_P(l) && SI_LINK_R_OPEN_P(l))

#define SI_LINK_SET_CLOSE_P(l)  ((l)->flags = SI_LINK_CLOSE)
#define SI_LINK_SET_OPEN_P(l, flag)   ((l)->flags = (l)->flags |SI_LINK_OPEN |flag)
#define SI_LINK_SET_W_OPEN_P(l) ((l)->flags = (l)->flags | SI_LINK_OPEN | SI_LINK_WRITE)
#define SI_LINK_SET_R_OPEN_P(l) ((l)->flags = (l)->flags | SI_LINK_OPEN | SI_LINK_READ)
#define SI_LINK_SET_RW_OPEN_P(l) ((l)->flags = (l)->flags | SI_LINK_OPEN | SI_LINK_READ | SI_LINK_WRITE)

BOOLEAN slOpen(si_link l, short flag);
BOOLEAN slClose(si_link l);
leftv   slRead(si_link l,leftv a=NULL);
BOOLEAN slWrite(si_link l, leftv v);
BOOLEAN slDump(si_link l);
BOOLEAN slGetDump(si_link l);
char* slStatus(si_link l, char *request);
char* slStatusAscii(si_link l, char* request);
BOOLEAN slInit(si_link l, char *str);
void slKill(si_link l);
void slCleanUp(si_link l);
void slStandardInit();
inline si_link slCopy(si_link l)
{
  l->ref++;
  return l;
}

#endif // SILINK_H