/*
                             *******************
******************************* C SOURCE FILE *******************************
**                           *******************                           **
**                                                                         **
** project      : The C Kernel                                             ** 
** filename     : CKMBOX.C                                                 **
** version      : 2                                                        **
** last revised : August 22, 2004                                          **
**                                                                         **
*****************************************************************************
**                                                                         **
** Copyright (c) 1998-2004, P.K. van der Vlugt                             **
** All rights reserved.                                                    **
**                                                                         **
*****************************************************************************

VERSION HISTORY:
----------------

Version     : 1
Date        : June 01, 2003
Revised by  : P.K. van der Vlugt
Description : Original version.

Version     : 2
Date        : August 22, 2004
Revised by  : P.K. van der Vlugt
Description : * Changed module name to comply to new kernel module naming 
                convention.

*/

#define _CKMBOX_C_SRC

/****************************************************************************/
/**                                                                        **/
/**                     MODULES USED                                       **/
/**                                                                        **/
/****************************************************************************/

#include "ckmbox.h"
#include "ckmsg.h"
#include "ckqueue.h"

/****************************************************************************/
/**                                                                        **/
/**                     DEFINITIONS AND MACROS                             **/
/**                                                                        **/
/****************************************************************************/

/****************************************************************************/
/**                                                                        **/
/**                     TYPEDEFS AND STRUCTURES                            **/
/**                                                                        **/
/****************************************************************************/

/****************************************************************************/
/**                                                                        **/
/**                     PROTOTYPES OF LOCAL FUNCTIONS                      **/
/**                                                                        **/
/****************************************************************************/

#if NR_OF_MBOXS > 0 && NR_OF_MSGS > 0
static void init (int8u id);

/****************************************************************************/
/**                                                                        **/
/**                     EXPORTED VARIABLES                                 **/
/**                                                                        **/
/****************************************************************************/

MboxType Mbox[NR_OF_MBOXS];

/****************************************************************************/
/**                                                                        **/
/**                     GLOBAL VARIABLES                                   **/
/**                                                                        **/
/****************************************************************************/

/****************************************************************************/
/**                                                                        **/
/**                     EXPORTED FUNCTIONS                                 **/
/**                                                                        **/
/****************************************************************************/

/****************************************************************************/
void MboxInit (void)
/****************************************************************************/
{
int8u id;

  /**** Initialize all id's ****/
  for (id = 0; id < NR_OF_MBOXS; id++)
    init (id);
}

/****************************************************************************/
int8u MboxAlloc (void)
/****************************************************************************/
{
int8u id;

  for (id = 0; id < NR_OF_MBOXS; id++)
  {
    /**** Search for a free Id ****/
    if (!Mbox[id].req)
    {
      /**** Allocate associated queue ****/
      Mbox[id].qid = QueueAlloc ();
      /**** Check if OK ****/
      if (Mbox[id].qid == NR_OF_QUEUES)
        return (NR_OF_MBOXS);
      break;
    }
  }

  /**** If found mark id as allocated ****/
  if (id < NR_OF_MBOXS)
    Mbox[id].req = TRUE;

  return (id);
}

/****************************************************************************/
void MboxFree (int8u id)
/****************************************************************************/
{
int8u msgId;

  /**** Cannot free illegal id ****/
  if (id >= NR_OF_MBOXS)
    return;

  /**** Free all the queued messages ****/
  msgId = Mbox[id].msgHead;
  while (msgId != Mbox[id].msgTail)
  {
    MsgFree (msgId);
    msgId = Msg[msgId].next;
  }

  /**** Free the associated queue ****/
  QueueFree (Mbox[id].qid);
  init (id);
}

/****************************************************************************/
int8u EnqueueMsg (int8u id, int32u msg)
/****************************************************************************/
{
int8u msgId, msgTail;

  /**** Allocate a new message ****/
  msgId = MsgAlloc ();
  if (msgId >= NR_OF_MSGS)
    return (NR_OF_MSGS);

  /**** Fill in the message field ****/
  SetMsg (msgId, msg);

  /**** Insert message in mailbox ****/
  msgTail = Mbox[id].msgTail;
  if (msgTail >= NR_OF_MSGS)
  {
    /**** No messages in mailbox ****/
    Mbox[id].msgHead = msgId;
    Mbox[id].msgTail = msgId;
  }
  else
  {
    /**** Add message to tail ****/
    Msg[msgTail].next = msgId;
    Mbox[id].msgTail  = msgId;
  }

  return (msgId);
}

/****************************************************************************/
int8u DequeueMsg (int8u id, int32u *msgPtr)
/****************************************************************************/
{
int8u msgHead, msgTail;

  /**** Get message head ****/
  msgHead = Mbox[id].msgHead;
  if (msgHead >= NR_OF_MSGS)
    return (NR_OF_MSGS);

  /**** Get message tail ****/
  msgTail = Mbox[id].msgTail;
  if (msgHead == msgTail)
  {
    /**** Last message was dequeued ****/
    Mbox[id].msgHead = NR_OF_MSGS;
    Mbox[id].msgTail = NR_OF_MSGS;
  }
  else
    /**** Not empty: adjust head ****/
    Mbox[id].msgHead = Msg[msgHead].next;

  /**** Get the message ****/
  *msgPtr = GetMsg (msgHead);
  /**** And free message item ****/
  MsgFree (msgHead);

  return (msgHead);
}

/****************************************************************************/
/**                                                                        **/
/**                     LOCAL FUNCTIONS                                    **/
/**                                                                        **/
/****************************************************************************/

/****************************************************************************/
static void init (int8u id)
/****************************************************************************/
{
  Mbox[id].req     = FALSE;
  Mbox[id].msgHead = NR_OF_MSGS;
  Mbox[id].msgTail = NR_OF_MSGS;
  Mbox[id].qid     = NR_OF_QUEUES;
  /**** Mark Mbox mode with FIFO_Q as default ****/
  Mbox[id].mode    = 0;
}
#endif

/****************************************************************************/
/**                                                                        **/
/**                               EOF                                      **/
/**                                                                        **/
/****************************************************************************/