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# mem_circ_queue.h

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    00001
    00002 /*
    00003  *   THIS FILE IS UNDER RCS - DO NOT MODIFY UNLESS YOU HAVE
    00004  *   CHECKED IT OUT USING THE COMMAND CHECKOUT.
    00005  *
    00006  *    $Id: mem__circ__queue_8h-source.html,v 1.1 2006/05/19 16:55:02 paulf Exp $
    00007  *
    00008  *    Revision history:
    00009  *     $Log: mem__circ__queue_8h-source.html,v $
    00009  *     Revision 1.1  2006/05/19 16:55:02  paulf
    00009  *     first inclusion
    00009  *
    00010  *     Revision 1.5  2001/04/12 03:59:07  lombard
    00011  *     changed "peak" to "peek"
    00012  *
    00013  *     Revision 1.4  2001/04/12 03:09:16  lombard
    00014  *     Added functions for saving queue to disk and recovering.
    00015  *
    00016  *     Revision 1.3  2001/01/14 22:16:07  lombard
    00017  *     spelling!
    00018  *
    00019  *     Revision 1.2  2001/01/14 22:14:44  lombard
    00020  *     added include file <transport.h>, required for use with mem_circ_queue.
    00021  *
    00022  *     Revision 1.1  2000/02/14 20:05:54  lucky
    00023  *     Initial revision
    00024  *
    00025  *
    00026  */
    00027
    00028
    00029 /* circular memory queue which allocates all its memory at startup */
    00030
    00031 #ifndef MEM_CIRC_QUEUE_H
    00032 #define MEM_CIRC_QUEUE_H
    00033
    00034 #include <transport.h>
    00035
    00036 /* The scheme involves three glops of memory:
    00037         a small structure QUEUE - one for each queue, defined below;
    00038         an array of message buffer descriptors  (QUEUE_ENTRY) and
    00039         a large region of message buffers where we'll store the messages
    00040         (each pointed to by d in the QUEUE_ENTRY structures).
    00041 */
    00042
    00043 typedef char*           DATA;
    00044 typedef int     Q_POS;
    00045
    00046
    00047 typedef struct
    00048 {
    00049    long               length;
    00050    MSG_LOGO           queueLogo;
    00051    DATA               d;
    00052 } QUEUE_ENTRY;
    00053
    00054 typedef  struct
    00055 {
    00056      QUEUE_ENTRY * pQE;  /* pointer to start of queue element array */
    00057      Q_POS     first;       /* position of the first(oldest) element of the queue */
    00058      Q_POS     last;        /* position of the last(youngest) element of the queue */
    00059      long      MyMaxSize;               /* largest message we'll ever see */
    00060      long      MyMaxElements;   /* number of message buffers in ring */
    00061      long      NumOfElements;
    00062
    00063 }  QUEUE;
    00064
    00065
    00066 int initqueue( QUEUE* q, unsigned long maxElements, unsigned long elementMaxSize );
    00067 int dequeue( QUEUE *q, DATA x, long* size, MSG_LOGO* userLogoPtr );
    00068 int enqueue( QUEUE *q, DATA x, long size, MSG_LOGO userLogo );
    00069 int getNumOfElementsInQueue( QUEUE * q);
    00070 int dumpqueue( QUEUE *p, char *filename);
    00071 int undumpqueue( QUEUE *q, char *filename);
    00072 Q_POS getNext(QUEUE * q, int QueuePosition);
    00073 Q_POS getPrev(QUEUE * q, int QueuePosition);
    00074 Q_POS getPosFirst(QUEUE * q);
    00075 Q_POS getPosLast(QUEUE * q);
    00076 DATA peekNextElement( QUEUE *q );
    00077
    00078 #endif