/*
** Copyright (C) 2004-2006 by Carnegie Mellon University.
**
** @OPENSOURCE_HEADER_START@
** 
** Use of the SILK system and related source code is subject to the terms 
** of the following licenses:
** 
** GNU Public License (GPL) Rights pursuant to Version 2, June 1991
** Government Purpose License Rights (GPLR) pursuant to DFARS 252.225-7013
** 
** NO WARRANTY
** 
** ANY INFORMATION, MATERIALS, SERVICES, INTELLECTUAL PROPERTY OR OTHER 
** PROPERTY OR RIGHTS GRANTED OR PROVIDED BY CARNEGIE MELLON UNIVERSITY 
** PURSUANT TO THIS LICENSE (HEREINAFTER THE "DELIVERABLES") ARE ON AN 
** "AS-IS" BASIS. CARNEGIE MELLON UNIVERSITY MAKES NO WARRANTIES OF ANY 
** KIND, EITHER EXPRESS OR IMPLIED AS TO ANY MATTER INCLUDING, BUT NOT 
** LIMITED TO, WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE, 
** MERCHANTABILITY, INFORMATIONAL CONTENT, NONINFRINGEMENT, OR ERROR-FREE 
** OPERATION. CARNEGIE MELLON UNIVERSITY SHALL NOT BE LIABLE FOR INDIRECT, 
** SPECIAL OR CONSEQUENTIAL DAMAGES, SUCH AS LOSS OF PROFITS OR INABILITY 
** TO USE SAID INTELLECTUAL PROPERTY, UNDER THIS LICENSE, REGARDLESS OF 
** WHETHER SUCH PARTY WAS AWARE OF THE POSSIBILITY OF SUCH DAMAGES. 
** LICENSEE AGREES THAT IT WILL NOT MAKE ANY WARRANTY ON BEHALF OF 
** CARNEGIE MELLON UNIVERSITY, EXPRESS OR IMPLIED, TO ANY PERSON 
** CONCERNING THE APPLICATION OF OR THE RESULTS TO BE OBTAINED WITH THE 
** DELIVERABLES UNDER THIS LICENSE.
** 
** Licensee hereby agrees to defend, indemnify, and hold harmless Carnegie 
** Mellon University, its trustees, officers, employees, and agents from 
** all claims or demands made against them (and any related losses, 
** expenses, or attorney's fees) arising out of, or relating to Licensee's 
** and/or its sub licensees' negligent use or willful misuse of or 
** negligent conduct or willful misconduct regarding the Software, 
** facilities, or other rights or assistance granted by Carnegie Mellon 
** University under this License, including, but not limited to, any 
** claims of product liability, personal injury, death, damage to 
** property, or violation of any laws or regulations.
** 
** Carnegie Mellon University Software Engineering Institute authored 
** documents are sponsored by the U.S. Department of Defense under 
** Contract F19628-00-C-0003. Carnegie Mellon University retains 
** copyrights in all material produced under this contract. The U.S. 
** Government retains a non-exclusive, royalty-free license to publish or 
** reproduce these documents, or allow others to do so, for U.S. 
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** 
** @OPENSOURCE_HEADER_END@
*/

/*
**  Deque API
**
*/


/* Includes */
#include "silk.h"

RCSIDENT("$SiLK: skdeque.c 3856 2006-05-26 15:38:34Z mwd $");

#include <string.h>
#include "skdqprivate.h"

/* Creates a copy of a deque.  Operations on both deques will affect each
   other. */
skDeque_t skDequeCopy(volatile skDeque_t deque)
{
    int oldtype;
    int die = 0;

    if (deque == NULL || deque->data == NULL) {
        return NULL;
    }
    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);
    if (deque->data == NULL) {
        die = 1;
    } else {
        deque->ref++;
    }
    pthread_cleanup_pop(1);
    pthread_setcanceltype(oldtype, NULL);

    if (die) {
        return NULL;
    }
  
    return deque;
}


/* Destroy and free a deque.  (Not reponsible for freeing the elements
   within the deque). */
skDQErr_t skDequeDestroy(skDeque_t deque)
{
    int oldtype;
    int destroy;

    if (deque == NULL) {
        return SKDQ_ERROR;
    }

    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);

    if ((destroy = (--deque->ref == 0))) {

        /* Call destructor method */
        deque->methods.destroy(deque);

        /* Mark as destroyed */
        deque->data = NULL;

        /* Give all the condition waiting threads a chance to exit. */
        pthread_cond_broadcast(deque->cond);
    }

    pthread_cleanup_pop(1);

    if (destroy) {
        while (pthread_mutex_destroy(deque->mutex) == EBUSY);
        while (pthread_cond_destroy(deque->cond) == EBUSY) {
            pthread_cond_broadcast(deque->cond);
        }
  
        free(deque);
    }

    pthread_setcanceltype(oldtype, NULL);

    return SKDQ_SUCCESS;
}


/* Return the status of a deque. */
skDQErr_t skDequeStatus(skDeque_t deque)
{
    int oldtype;
    skDQErr_t retval;

    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);

    retval = deque->methods.status(deque);
  
    pthread_cleanup_pop(1);
    pthread_setcanceltype(oldtype, NULL);

    return retval;
}

/* Return the size of a deque. */
uint32_t skDequeSize(skDeque_t deque)
{
    int oldtype;
    skDQErr_t retval;

    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);

    retval = deque->methods.size(deque);
  
    pthread_cleanup_pop(1);
    pthread_setcanceltype(oldtype, NULL);

    return retval;
}


/* Pop an element from a deque.  */
static skDQErr_t sk_deque_pop(skDeque_t deque, void **item,	
			      uint8_t block, uint8_t front, 
                              uint32_t seconds)
{
    int oldtype;
    skDQErr_t retval;

    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);

    retval = deque->methods.pop(deque, item, block, front, seconds);
  
    pthread_cleanup_pop(1);
    pthread_setcanceltype(oldtype, NULL);

    return retval;
}



/* Pop an element from a deque.  

skDequePop{Front,Back} will block until an item is available in the
deque.  skDequePop{Front,Back}NB will return SKDQ_EMPTY if the
deque is empty instead. */
skDQErr_t skDequePopFront(skDeque_t deque, void **item)
{
    return sk_deque_pop(deque, item, 1, 1, 0);
}
skDQErr_t skDequePopFrontNB(skDeque_t deque, void **item)
{
    return sk_deque_pop(deque, item, 0, 1, 0);
}
skDQErr_t skDequePopFrontTimed(skDeque_t deque, void **item, uint32_t seconds)
{
    return sk_deque_pop(deque, item, 1, 1, seconds);
}
skDQErr_t skDequePopBack(skDeque_t deque, void **item)
{
    return sk_deque_pop(deque, item, 1, 0, 0);
}
skDQErr_t skDequePopBackNB(skDeque_t deque, void **item)
{
    return sk_deque_pop(deque, item, 0, 0, 0);
}
skDQErr_t skDequePopBackTimed(skDeque_t deque, void **item, uint32_t seconds)
{
    return sk_deque_pop(deque, item, 1, 0, seconds);
}


/* Peek at an element from a deque. */
static skDQErr_t sk_deque_peek(skDeque_t deque, void **item, uint8_t front)
{
    int oldtype;
    skDQErr_t retval;

    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);

    retval = deque->methods.peek(deque, item, front);
  
    pthread_cleanup_pop(1);
    pthread_setcanceltype(oldtype, NULL);

    return retval;
}


/* Return the first or last element of a deque without removing it, or
   SKDQ_EMPTY if the deque is empty.  */
skDQErr_t skDequeFront(skDeque_t deque, void **item)
{
    return sk_deque_peek(deque, item, 1);
}
skDQErr_t skDequeBack(skDeque_t deque, void **item)
{
    return sk_deque_peek(deque, item, 0);
}

/* Peek at an element from a deque. */
static skDQErr_t sk_deque_push(skDeque_t deque, void *item, uint8_t front)
{
    int oldtype;
    skDQErr_t retval;

    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);

    retval = deque->methods.push(deque, item, front);
  
    pthread_cleanup_pop(1);
    pthread_setcanceltype(oldtype, NULL);

    return retval;
}

skDQErr_t skDequeUnblock(skDeque_t deque)
{
    int oldtype;
    skDQErr_t retval;

    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);

    retval = deque->methods.block(deque, 0);
  
    pthread_cleanup_pop(1);
    pthread_setcanceltype(oldtype, NULL);

    return retval;
}


skDQErr_t skDequeBlock(skDeque_t deque)
{
    int oldtype;
    skDQErr_t retval;

    pthread_setcanceltype(PTHREAD_CANCEL_DEFERRED, &oldtype);
    pthread_cleanup_push((callbackfn_t)pthread_mutex_unlock, 
                         (void *)deque->mutex);
    pthread_mutex_lock(deque->mutex);

    retval = deque->methods.block(deque, 1);
  
    pthread_cleanup_pop(1);
    pthread_setcanceltype(oldtype, NULL);

    return retval;
}

/* Push an item onto a deque. */
skDQErr_t skDequePushFront(skDeque_t deque, void *item)
{
    return sk_deque_push(deque, item, 1);
}
skDQErr_t skDequePushBack(skDeque_t deque, void *item)
{
    return sk_deque_push(deque, item, 0);
}