messshm.h

//
// messshm.h
//
// Copyright (C) 1996 Limit Point Systems, Inc.
//
// Author: Curtis Janssen <cljanss@limitpt.com>
// Maintainer: LPS
//
// This file is part of the SC Toolkit.
//
// The SC Toolkit is free software; you can redistribute it and/or modify
// it under the terms of the GNU Library General Public License as published by
// the Free Software Foundation; either version 2, or (at your option)
// any later version.
//
// The SC Toolkit is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU Library General Public License for more details.
//
// You should have received a copy of the GNU Library General Public License
// along with the SC Toolkit; see the file COPYING.LIB.  If not, write to
// the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA.
//
// The U.S. Government is granted a limited license as per AL 91-7.
//
 
#ifndef _util_group_messshm_h
#define _util_group_messshm_h
 
#include <unistd.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
 
#include <util/group/message.h>
 
namespace sc {
 
#define SHMCOMMBUFSIZE 1500000
 
/* Set the maximum number of processors (including the host). */
#define MAXPROCS 17
 
 
struct commbuf_struct {
    int nmsg;
    int n_wait_for_change;
    int n_sync;
    char buf[SHMCOMMBUFSIZE];
};
typedef struct commbuf_struct commbuf_t;
 
struct msgbuf_struct {
    int type;
    int from;
    int size;
};
typedef struct msgbuf_struct msgbuf_t;
 
class ShmMessageGrp: public intMessageGrp {
  protected:
    void basic_send(int target, int type, const void* data, int nbyte);
    void basic_recv(int type, void* data, int nbyte);
    int basic_probe(int type);
    void initialize(int nprocs);
    void initialize();
 
    // previously static variables
    commbuf_t *commbuf[MAXPROCS];
    int shmid;
    int semid;
    int change_semid;
    void* sharedmem;
    struct sembuf semdec;
    struct sembuf seminc;
 
    // previously static functions for semephore operations
    msgbuf_t *NEXT_MESSAGE(msgbuf_t *m);
    void get_change(int node);
    void put_change(int node);
    void wait_for_write(int node);
    void release_write(int node);
#ifdef DEBUG
    void print_buffer(int node, int me);
#endif
  public:
    ShmMessageGrp();
    ShmMessageGrp(const Ref<KeyVal>&);
    ShmMessageGrp(int nprocs);
    ~ShmMessageGrp();
    void sync();
 
    Ref<MessageGrp> clone(void);
};
 
}
     
#endif
 
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