examples/PIPS/opencmessagequeuelibraryex/engine/src/msgqinternals.c

/*
Copyright (c) 2007-2010 Nokia Corporation and/or its subsidiary(-ies). All rights reserved.

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

* Redistributions of source code must retain the above copyright notice, this
  list of conditions and the following disclaimer.
* Redistributions in binary form must reproduce the above copyright notice,
  this list of conditions and the following disclaimer in the documentation
  and/or other materials provided with the distribution.
* Neither the name of Nokia Corporation nor the names of its contributors
  may be used to endorse or promote products derived from this software
  without specific prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

Description:  
*/


#include <stdlib.h>
#include "MsgQInternal.h"


/* Declaration and definition of Internal Functions and data structures */
MSGQ_INFO_PTR        MsgQInfo[MSGQ_TBL_SZ];
MSGQ_INFO_LIST_PTR   MsgQListHead = NULL;

inline unsigned int HashIndex(ULONG qName);

/*************** INTERNAL FUNCTIONS ******************************/

/***************************************************************************
*  InstallMsqQTable (qName, qid, semId, sendState, numMsgs, err)
*  Function: This function installs a queue into the hash table
****************************************************************************/

int InstallMsqQTable(ULONG qName, int qId, int semId, int* err) {

        MSGQ_INFO_PTR pMsgQInfo = NULL;
        unsigned int  index;

        if ((pMsgQInfo = MsgQTableLookup(qName)) == NULL) {
                pMsgQInfo = (MSGQ_INFO_PTR)malloc(sizeof(*pMsgQInfo));

                if(pMsgQInfo != NULL) {
                        index = HashIndex(qName);

                        pMsgQInfo->next  = MsgQInfo[index];
                        MsgQInfo[index]   = pMsgQInfo;
                        pMsgQInfo->qName = qName;
                        pMsgQInfo->qId   = qId;
                        pMsgQInfo->semId = semId;
                        pMsgQInfo->sendState = MSG_Q_READY;
                        pMsgQInfo->numMsgs   = 0;

                        *err = OK;
                        return (OK);
                }
                else
                        *err = KMsgQLibNoMemoryErr;
        }
        else
                *err = KMsgQLibQIdErr;

        return(ERROR);

}


/******************************************************************************
*  HashIndex
*  Function: This function returns the hash index
*******************************************************************************/

inline unsigned int HashIndex(ULONG qName) {
        return(qName % MSGQ_TBL_SZ);
}


/************************************************************************
*  MsgQTableLookup (qName)
*  Function: This function finds the block pointer for each queue
*************************************************************************/

MSGQ_INFO* MsgQTableLookup(ULONG qName) {
        MSGQ_INFO_PTR pMsgQInfo = NULL;

        for (pMsgQInfo = MsgQInfo[HashIndex(qName)]; pMsgQInfo != NULL; pMsgQInfo = pMsgQInfo->next) {
                if (qName == pMsgQInfo->qName)
                        return(pMsgQInfo);
        }

        return(NULL);
}


/*************************************************************************
*  RemoveFromMsqQTable (qName, err)
*  Function: This function removes a queue from the hash table
**************************************************************************/


int RemoveFromMsqQTable(ULONG qName, int* err) {
        unsigned int  index = 0;
        MSGQ_INFO_PTR prev = NULL;
        MSGQ_INFO_PTR pMsgQInfo = NULL;

        index = HashIndex(qName);
        for (pMsgQInfo = MsgQInfo[index]; pMsgQInfo != NULL; pMsgQInfo = pMsgQInfo->next) {
                if (qName == pMsgQInfo->qName)
                        break;
                prev = pMsgQInfo;
        }

        if (pMsgQInfo != NULL) {
                if (prev == NULL)
                        MsgQInfo[index] = pMsgQInfo->next;
                else
                        prev->next = pMsgQInfo->next;

                free((void*)pMsgQInfo);
                *err = OK;
                return (OK);
        }
        else
                *err = KMsgQLibQIdErr;

        return(ERROR);
}


/************************************************************************
*  AddToMsgQTable (qName)
*  Function: Adding a queue to list
*************************************************************************/

void AddToMsgQTable(ULONG qName) {
        MSGQ_INFO_LIST_PTR tempNext;

        if (MsgQListHead != NULL) {
                /* subsequent entries */
                tempNext = MsgQListHead->next;

                if ((MsgQListHead->next = (MSGQ_INFO_LIST*)malloc(sizeof(MSGQ_INFO_LIST))) != NULL)             {
                        MsgQListHead->next->next = tempNext;
                        MsgQListHead->next->qName = qName;
                }
                else 
                        MsgQListHead->next = tempNext;
        }
        else {
                if ((MsgQListHead = (MSGQ_INFO_LIST*)malloc(sizeof(MSGQ_INFO_LIST))) != NULL) {
                        MsgQListHead->next = NULL;
                        MsgQListHead->qName = qName;
                }
        }
}

/************************************************************************
*  DeleteFromMsgQTable (qName)
*  Function:  removing a queu entry from  list
*************************************************************************/

void DeleteFromMsgQTable(ULONG qName) {
        MSGQ_INFO_LIST_PTR prev = NULL;
        MSGQ_INFO_LIST_PTR pMsgQInfo = NULL;

        for (pMsgQInfo = MsgQListHead; pMsgQInfo != NULL; pMsgQInfo = pMsgQInfo->next) {
                if (qName == pMsgQInfo->qName)
                        break;
                prev = pMsgQInfo;
        }

        if (pMsgQInfo != NULL) {
                /* Check whether prev pointer is null or not. If it is Null, update Head pointer */
                if( prev == NULL )
                        MsgQListHead = MsgQListHead->next ;

                /* Else update the linked list by removing present node and updating prev next pointer */
                else
                        prev->next = pMsgQInfo->next;

                /* Now free up the memory used by the present node */
                free((void*) pMsgQInfo);
        }
}

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