/*---------------------------------------------------------------------------*
  Project:  TwlSDK - OS
  File:     os_message.c

  Copyright 2003-2008 Nintendo.  All rights reserved.

  These coded instructions, statements, and computer programs contain
  proprietary information of Nintendo of America Inc. and/or Nintendo
  Company Ltd., and are protected by Federal copyright law.  They may
  not be disclosed to third parties or copied or duplicated in any form,
  in whole or in part, without the prior written consent of Nintendo.

  $Date::            $
  $Rev$
  $Author$

 *---------------------------------------------------------------------------*/
#include  <brom/os.h>
#include  <brom/os/common/message.h>

/*---------------------------------------------------------------------------*
  Name:         osInitMessageQueue

  Description:  initialize message queue

  Arguments:    mq          message queue
                msgArray    buffer for message queue
                msgCount    max massage size for buffer

  Returns:      None
 *---------------------------------------------------------------------------*/
void osInitMessageQueue(OSMessageQueue *mq, OSMessage *msgArray, s32 msgCount)
{
    osInitThreadQueue(&mq->queueSend);
    osInitThreadQueue(&mq->queueReceive);
    mq->msgArray = msgArray;
    mq->msgCount = msgCount;
    mq->firstIndex = 0;
    mq->usedCount = 0;
}

/*---------------------------------------------------------------------------*
  Name:         osSendMessage

  Description:  send message to message queue

  Arguments:    mq          message queue
                msg         massage which is sent
                flags       whether wait or not when queue is full

  Returns:      TRUE if send
                
 *---------------------------------------------------------------------------*/
BOOL osSendMessage(OSMessageQueue *mq, OSMessage msg, s32 flags)
{
    OSIntrMode enabled;
    s32     lastIndex;

    enabled = osDisableInterrupts();

    while (mq->msgCount <= mq->usedCount)       // check for full queue
    {
        if (!(flags & OS_MESSAGE_BLOCK))
        {
            (void)osRestoreInterrupts(enabled);
            return FALSE;
        }
        else
        {
            // Yield
            osSleepThread(&mq->queueSend);
        }
    }

    // Store message
    lastIndex = (mq->firstIndex + mq->usedCount) % mq->msgCount;
    mq->msgArray[lastIndex] = msg;
    mq->usedCount++;

    // Wakeup receiving threads if any
    osWakeupThread(&mq->queueReceive);

    (void)osRestoreInterrupts(enabled);
    return TRUE;
}

/*---------------------------------------------------------------------------*
  Name:         osReceiveMessage

  Description:  receive message from message queue

  Arguments:    mq          message queue
                msg         massage which is received
                flags       whether wait or not when queue is empty

  Returns:      TRUE if reveice
                
 *---------------------------------------------------------------------------*/
BOOL osReceiveMessage(OSMessageQueue *mq, OSMessage *msg, s32 flags)
{
    OSIntrMode enabled;

    enabled = osDisableInterrupts();

    while (mq->usedCount == 0)         // check for empty queue
    {
        if (!(flags & OS_MESSAGE_BLOCK))
        {
            (void)osRestoreInterrupts(enabled);
            return FALSE;
        }
        else
        {
            // Yield
            osSleepThread(&mq->queueReceive);
        }
    }

    // Copy-out message
    if (msg != NULL)
    {
        *msg = mq->msgArray[mq->firstIndex];
    }
    mq->firstIndex = (mq->firstIndex + 1) % mq->msgCount;
    mq->usedCount--;

    // Wakeup sending threads if any
    osWakeupThread(&mq->queueSend);

    (void)osRestoreInterrupts(enabled);
    return TRUE;
}


/*---------------------------------------------------------------------------*
  Name:         osJamMessage

  Description:  send message to message queue, cutting in the top of the queue

  Arguments:    mq          message queue
                msg         massage which is sent
                flags       whether wait or not when queue is full

  Returns:      TRUE if send
                
 *---------------------------------------------------------------------------*/
BOOL osJamMessage(OSMessageQueue *mq, OSMessage msg, s32 flags)
{
    OSIntrMode enabled;

    enabled = osDisableInterrupts();

    while (mq->msgCount <= mq->usedCount)       // check for full queue
    {
        if (!(flags & OS_MESSAGE_BLOCK))
        {
            (void)osRestoreInterrupts(enabled);
            return FALSE;
        }
        else
        {
            // Yield
            osSleepThread(&mq->queueSend);
        }
    }

    // Store message at the front
    mq->firstIndex = (mq->firstIndex + mq->msgCount - 1) % mq->msgCount;
    mq->msgArray[mq->firstIndex] = msg;
    mq->usedCount++;

    // Wakeup receiving threads if any
    osWakeupThread(&mq->queueReceive);

    (void)osRestoreInterrupts(enabled);
    return TRUE;
}


/*---------------------------------------------------------------------------*
  Name:         osReadMessage

  Description:  read message at message queue. no change in queue
                not occur to switch threads.

  Arguments:    mq          message queue
                msg         massage which is received
                flags       whether wait or not when queue is empty

  Returns:      TRUE if read
                
 *---------------------------------------------------------------------------*/
BOOL osReadMessage(OSMessageQueue *mq, OSMessage *msg, s32 flags)
{
    OSIntrMode enabled;

    enabled = osDisableInterrupts();

    while (mq->usedCount == 0)         // check for empty queue
    {
        if (!(flags & OS_MESSAGE_BLOCK))
        {
            (void)osRestoreInterrupts(enabled);
            return FALSE;
        }
        else
        {
            // Yield
            osSleepThread(&mq->queueReceive);
        }
    }

    // Copy-out message
    if (msg != NULL)
    {
        *msg = mq->msgArray[mq->firstIndex];
    }

    (void)osRestoreInterrupts(enabled);
    return TRUE;
}