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#ifndef CYGONCE_KERNEL_MQUEUE_HXX

#define CYGONCE_KERNEL_MQUEUE_HXX

/*========================================================================

//

//      mqueue.hxx

//

//      Message queues

//

//========================================================================

//####ECOSGPLCOPYRIGHTBEGIN####

// -------------------------------------------

// This file is part of eCos, the Embedded Configurable Operating System.

// Copyright (C) 1998, 1999, 2000, 2001, 2002 Red Hat, Inc.

//

// eCos 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 or (at your option) any later version.

//

// eCos 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 eCos; if not, write to the Free Software Foundation, Inc.,

// 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.

//

// As a special exception, if other files instantiate templates or use macros

// or inline functions from this file, or you compile this file and link it

// with other works to produce a work based on this file, this file does not

// by itself cause the resulting work to be covered by the GNU General Public

// License. However the source code for this file must still be made available

// in accordance with section (3) of the GNU General Public License.

//

// This exception does not invalidate any other reasons why a work based on

// this file might be covered by the GNU General Public License.

//

// Alternative licenses for eCos may be arranged by contacting Red Hat, Inc.

// at http://sources.redhat.com/ecos/ecos-license/

// -------------------------------------------

//####ECOSGPLCOPYRIGHTEND####

//========================================================================

//#####DESCRIPTIONBEGIN####

//

// Author(s):     jlarmour

// Contributors:

// Date:          2000-05-09

// Purpose:       This file provides the interface for eCos message queues

// Description:   This differs from the message boxes also supported by

//                eCos primarily because the requirements of message

//                queues are driven by POSIX semantics. POSIX semantics are

//                more dynamic and therefore heavyweight than Mboxes,

//                including prioritization, and variable sized queues and

//                message lengths

// Usage:         #include 

//

//####DESCRIPTIONEND####

//

//======================================================================

*/

/* CONFIGURATION */

#include           /* Configuration header */

/* INCLUDES */

#include                   /* size_t */

#include       /* Types */

#include        /* CYGDBG_DEFINE_CHECK_THIS,

                                        CYGDBG_USE_ASSERTS */

#include        /* Kernel package types */

#include        /* Cyg_Counting_Semaphore */

/* CLASSES */

class Cyg_Mqueue {

public:

    typedef void (*callback_fn_t)(Cyg_Mqueue &q, CYG_ADDRWORD data);

    typedef void * (*qalloc_fn_t)(size_t len);

    typedef void (*qfree_fn_t)(void *ptr, size_t len);

    typedef enum {

        OK=0,

        NOMEM,

        WOULDBLOCK,

#ifdef CYGFUN_KERNEL_THREADS_TIMER

        TIMEOUT,

#endif

        INTR

    } qerr_t;

protected:

    struct qentry {

        struct qentry *next;

        unsigned int priority;

        size_t buflen;

        volatile bool busy;

        // data buffer follows here

        char *buf() const { return (char *)this + sizeof(*this); }

    };

    Cyg_Counting_Semaphore putsem, getsem;

    struct qentry *q;            // q entries in use

    struct qentry *freelist;     // q entries not in use

    void *queuespace;            // placeholder for the dynamically allocated

                                 // area

    size_t queuespacesize;

    qfree_fn_t free_fn;          // how to free queuespace when we destruct

    callback_fn_t callback;

    CYG_ADDRWORD callback_data;

    CYGDBG_DEFINE_CHECK_THIS

#ifdef CYGDBG_USE_ASSERTS

    long qlen;

    size_t msgsize;

#endif

public:

    Cyg_Mqueue( long maxmsgs, long maxmsgsize,

                qalloc_fn_t qalloc, qfree_fn_t qfree, qerr_t *err );

    ~Cyg_Mqueue();

    // put() copies len bytes of *buf into the queue at priority prio

    qerr_t put( const char *buf, size_t len, unsigned int prio, bool block=true

#ifdef CYGFUN_KERNEL_THREADS_TIMER

                ,cyg_tick_count timeout = 0

#endif

              );

    // get() returns the oldest highest priority message in the queue in *buf

    // and sets *prio to the priority (if prio is non-NULL) and *len to the

    // actual message size

    qerr_t get( char *buf, size_t *len, unsigned int *prio, bool block=true

#ifdef CYGFUN_KERNEL_THREADS_TIMER

                ,cyg_tick_count timeout = 0

#endif

              );

    // count() returns the number of messages in the queue

    long count();

    // Supply a callback function to call (with the supplied data argument)

    // when the queue goes from empty to non-empty (unless someone's already

    // doing a get()). This returns the old callback_fn, and if olddata is

    // non-NULL sets it to the old data (yes, really!)

    callback_fn_t setnotify( callback_fn_t callback_fn, CYG_ADDRWORD data,

                             CYG_ADDRWORD *olddata=NULL);

}; /* class Cyg_Mqueue */

#ifndef CYGIMP_KERNEL_SYNCH_MQUEUE_NOT_INLINE

# include 

#endif

#endif /* CYGONCE_KERNEL_MQUEUE_HXX multiple inclusion protection */

/* EOF mqueue.hxx */