/*
 * UPIWIN - Micro Pi Windowing Framework Kernel
 * Copyright (C) 2019 Amy Bowersox/Erbosoft Metaverse Design Solutions
 *    
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *    
 * This program 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License along
 * with this program; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *-------------------------------------------------------------------------
 */
#ifndef __MSG_QUEUE_H_INCLUDED
#define __MSG_QUEUE_H_INCLUDED

#include <pthread.h>
#include "wintype.h"
#include "msg.h"

/* internal structure of a message queue */
typedef struct tagMSG_QUEUE {
  struct tagMSG_QUEUE *next;    /* allow us to be in a singly-linked list */
  PMSG startbound;              /* start boundary for message buffer */
  PMSG endbound;                /* end boundary for message buffer */
  PMSG head;                    /* head pointer of message queue */
  PMSG tail;                    /* tail pointer of message queue */
  UINT32 nentries;              /* number of entries possible in message buffer */
  pthread_mutex_t mutex;        /* controls access to queue from multiple threads */
  MSG messagestore[0];          /* message buffer */
} MSG_QUEUE, *PMSG_QUEUE;

/* flags to Mq_peek */
#define PEEK_REMOVE   0x0001    /* remove message if found */
#define PEEK_NOREMOVE 0x0000    /* do not remove message if found */

extern PMSG_QUEUE Mq_alloc(UINT32 nentries);
extern void Mq_destroy(PMSG_QUEUE queue);
extern void Mq_post(PMSG_QUEUE queue, HANDLE target, UINT32 message, const UINT_PTR *attrs, int nattrs);
extern void Mq_post2(PMSG_QUEUE queue, HANDLE target, UINT32 message, UINT_PTR attr1, UINT_PTR attr2);
extern BOOL Mq_peek(PMSG_QUEUE queue, PMSG msg, UINT32 flags);
extern BOOL Mq_is_empty(PMSG_QUEUE queue);

#define Mq_post0(q, tgt, msg)         Mq_post2(q, tgt, msg, 0, 0)
#define Mq_post1(q, tgt, msg, attr)   Mq_post2(q, tgt, msg, attr, 0)

#endif /* __MSG_QUEUE_H_INCLUDED */
