binding-c/runtime/c/src/main/transport/etch_queue.c - etch - Git at Google

 /* $Id$
  *
  * Licensed to the Apache Software Foundation (ASF) under one or more
  * contributor license agreements. See the NOTICE file distributed with
  * this work for additional information regarding copyright ownership.
  * The ASF licenses this file to you under the Apache License, Version
  * 2.0 (the "License"); you may not use this file except in compliance
  * with the License. You may obtain a copy of the License at
  *
  * http://www.apache.org/licenses/LICENSE-2.0
  *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  * See the License for the specific language governing permissions and
  * limitations under the License.
  */

 /**
  * etch_queue.c
  */

 #include "etch_queue.h"
 #include "etch_thread.h"
 #include "etch_log.h"
 #include "etch_mem.h"
 #include "etch_runtime.h"
 #include "etch_objecttypes.h"

 /*
 static const char* LOG_CATEGORY = "etch_queue";
 */

 extern apr_pool_t*         g_etch_main_pool;

 int  destroy_etch_queue(void*);
 void etchqueue_clear(etch_queue*);
 int  etchqueue_iterable_first(etch_iterator*);
 int  etchqueue_iterable_next(etch_iterator*);
 int  etchqueue_iterable_has_next(etch_iterator*);


 /**
  * new_queue()
  * etch_queue constructor
  */
 etch_queue* new_queue(const int initialsize)
 {
     etch_queue* newq = NULL;
     etch_apr_queue_t* aprq = NULL;
     apr_pool_t* newsubpool = NULL;
     int result = -1, qsize = initialsize > 0? initialsize: ETCH_DEFQSIZE;

     do
     {

         // TODO: pool
         result = apr_pool_create(&newsubpool, g_etch_main_pool);
         //printf("2 creating apr pool %p\n",newsubpool);
         if (0 != result) break;
         /* set pool abort function */
         apr_pool_abort_set(etch_runtime_mem_abort, newsubpool);


         result = etch_apr_queue_create (&aprq, qsize, newsubpool);
         if (0 != result) break;

         newq = (etch_queue*) new_object(sizeof(etch_queue), ETCHTYPEB_ETCHQUEUE, CLASSID_ETCHQUEUE);

         newq->aprq = aprq;
         newq->subpool = newsubpool;
         newq->qcapacity = initialsize;
         ((etch_object*)newq)->destroy = destroy_etch_queue;
         /* assume content to be etch objects owned by the queue */
         newq->is_readonly  = FALSE;
         newq->content_type = ETCHQUEUE_CONTENT_OBJECT;

         new_iterable(&newq->iterable, NULL, etchqueue_iterable_first,
             etchqueue_iterable_next, etchqueue_iterable_has_next);

         result = 0;

     } while(0);

     if (0 != result)
     {
         if (newsubpool) {
             //printf("3 destroying apr pool %p\n",newsubpool);
             apr_pool_destroy(newsubpool);
         }
     }

     return newq;
 }


 /*
  * destroy_etch_queue()
  * etch_queue destructor
  */
 int destroy_etch_queue(void* data)
 {
     etch_queue* queue = (etch_queue*)data;
     if (NULL == queue) return -1;

     if  (-1 == etch_apr_queue_trylock(queue->aprq))
          return -1;
     else etch_apr_queue_unlock(queue->aprq);

     if (!is_etchobj_static_content(queue))
     {
         /* free etch-managed memory */
         etchqueue_clear(queue);

         /* free APR-managed memory - APR queue sets a callback such that
          * destroying the memory pool destroys the APR queue object */
         if (queue->subpool)  {
             //printf("4 destroying apr pool %p\n",queue->subpool);
             apr_pool_destroy(queue->subpool);
         }

         queue->subpool = NULL;
         queue->aprq = NULL;
     }

     return destroy_objectex((etch_object*)queue);
 }


 /*
  * etchqueue_clear()
  * frees queue content memory.
  * this ensures the underlying queue is closed, so it is only invoked prior to
  * destruction of the queue in order to free any remaining queued etch objects.
  * all other memory associated with the queue, other than the shell object,
  * is managed by APR.
  */
 void etchqueue_clear(etch_queue* thisx)
 {
     if (NULL == thisx || NULL == thisx->aprq || thisx->is_readonly) return;
     etchqueue_close(thisx, TRUE); /* close queue and notify all waiters */

     do
     {   void* qobj = NULL;
         queuecallback callback = thisx->freehook;
         int i = 0, is_freehandled = 0, result = 0;
         const int is_obj_content = thisx->content_type == ETCHQUEUE_CONTENT_OBJECT;

         while(1)
         {
             result = etchqueue_get_withwait (thisx, ETCHQUEUE_CLEARING_CLOSED_QUEUE, &qobj);
             if (0 != result) break;

             is_freehandled = callback? callback(i, qobj): FALSE;

             if  (is_freehandled);
             else
             if  (is_obj_content)
                 ((etch_object*)qobj)->destroy(qobj);
             else etch_free(qobj);
         }

     } while(0);
 }


 /**
  * etchqueue_size()
  * @return current queue depth
  * not thread-safe, caller should hold the mailbox queue lock
  */
 int etchqueue_size(etch_queue* thisx)
 {
     return thisx && thisx->aprq? etch_apr_queue_size(thisx->aprq): 0;
 }


 /**
  * etchqueue_is_closed()
  * not thread-safe, caller should hold the mailbox queue lock
  */
 int etchqueue_is_closed(etch_queue* thisx)
 {
     return thisx && thisx->aprq? thisx->aprq->terminated != 0: TRUE;
 }


 /**
  * etchqueue_is_full()
  * not thread-safe, caller should hold the mailbox queue lock
  */
 int etchqueue_is_full(etch_queue* thisx)
 {
     return thisx && thisx->aprq? thisx->aprq->nelts == thisx->aprq->bounds: TRUE;
 }


 /**
  * etchqueue_close()
  * underlying implementation ensures operation atomicity
  */
 int etchqueue_close(etch_queue* thisx, const int is_needlock)
 {
     int result = 0;

     if (!etchqueue_is_closed(thisx))
     {
         if (is_needlock)
             result = etch_apr_queue_term(thisx->aprq);
         else
             result = etch_apr_queue_unsafeclose(thisx->aprq);

         result = result == 0? 0: -1;
     }
     return result;
 }


 /**
  * etchqueue_put()
  * push specified item onto the queue. if the queue is full,
  * wait indefinitely until space becomes available.
  * @return 0 success, -1 error.
  */
 int etchqueue_put(etch_queue* thisx, void* item)
 {
     const int result = etchqueue_put_withwait(thisx, ETCH_INFWAIT, item);
     return result;
 }


 /**
  * etchqueue_put_withwait()
  * push specified item onto the queue. if the queue is full,
  * waitms specified time interval until space becomes available.
  * @param waitms wait interval in milliseconds. specify ETCH_INFWAIT to wait
  * forever, ETCH_NOWAIT to not wait.
  * @return 0 success, -1 unsuccessful.
  *
  */
 int etchqueue_put_withwait(etch_queue* thisx, const int waitms, void* item)
 {
     int result = 0, aprresult = 0;
     const int64 wait_usec = waitms < 0? -1: waitms * 1000;
     if (NULL == item || etchqueue_is_closed(thisx)) return -1;

     /*
      * etch_apr_queue_push() takes care of notifying threads waiting on a
      * queue slot to become available, if any.
      */
     aprresult = etch_apr_queue_push (thisx->aprq, wait_usec, item);

     switch(aprresult)
     {   case APR_SUCCESS: break;

         case APR_EAGAIN: /* timed out and queue still full */
         case APR_TIMEUP:
              result = ETCH_QUEUE_OPERATION_TIMEOUT;
              break;

         case APR_EINTR:  /* wait interrupted and queue still full */
              result = ETCH_QUEUE_OPERATION_CANCELED;
              break;

         case APR_EOF:    /* queue closed */
              default:    /* some error */
              result = -1;
     }

     return result;
 }


 /**
  * etchqueue_get()
  * pop specified item off the queue and return it. if the queue is empty,
  * wait indefinitely for an item to arrive. popped item is returned in
  * out parameter.
  * @return 0 success, -1 error.
  */
 int etchqueue_get(etch_queue* thisx, void** itemout)
 {
     const int result = etchqueue_get_withwait(thisx, ETCH_INFWAIT, itemout);
     return result;
 }


 /**
  * etchqueue_get_withwait()
  * pop specified item off the queue and return it. if the queue is empty,
  * wait specified time interval for an item to arrive. popped item is
  * returned in out parameter.
  * @param waitms wait interval in milliseconds. specify ETCH_INFWAIT to wait
  * forever, ETCH_NOWAIT to not wait, ETCHQUEUE_CLEARING_CLOSED_QUEUE to do a
  * get with no wait regardless of whether queue has been closed.
  * @return 0 success, -1 unsuccessful.
  *
  */
 int etchqueue_get_withwait(etch_queue* thisx, const int waitms, void** itemout)
 {
     int result = 0, aprresult = 0;
     const int64 wait_usec = waitms < 0? waitms: waitms * 1000;

     if (etchqueue_is_closed(thisx))
         if (waitms != ETCHQUEUE_CLEARING_CLOSED_QUEUE)
             return -1;

     /*
      * etch_apr_queue_pop() takes care of notifying waiters if necessary
      */
     aprresult = etch_apr_queue_pop (thisx->aprq, wait_usec, itemout);

     switch(aprresult)
     {   case APR_SUCCESS: break;

         case APR_EAGAIN: /* timed out and queue still full */
         case APR_TIMEUP:
              result = ETCH_QUEUE_OPERATION_TIMEOUT; break;

         case APR_EINTR:  /* wait interrupted and queue still empty */
              result = ETCH_QUEUE_OPERATION_CANCELED; break;

         case APR_EOF:    /* queue empty */
              result = ETCH_QUEUE_EOF; break;

         default:         /* some error */
              result = -1;
     }

     return result;
 }


 /**
  * etchqueue_try_put()
  * @return 0 success, -1 unsuccessful.
  *
  */
 int etchqueue_try_put(etch_queue* thisx, void* item)
 {
     const int result = etch_apr_queue_trypush(thisx->aprq, item);
     return result == 0? 0: -1;
 }


 /**
  * etchqueue_try_get()
  * @return 0 success, -1 unsuccessful.
  */
 int etchqueue_try_get(etch_queue* thisx, void** itemout)
 {
     const int result = etch_apr_queue_trypop(thisx->aprq, itemout);
     return result == 0? 0: -1;
 }


  /**
  * etchqueue_notify_all()
  * wake up all waiters,
  * @return 0 success, -1 unsuccessful.
  */
 int etchqueue_notify_all(etch_queue* thisx)
 {
     const int aprresult = etch_apr_queue_interrupt_all(thisx->aprq);
     return aprresult == 0? 0: -1;
 }


 /**
  * acquire the lock guarding the queue
  */
 int etchqueue_lock(etch_queue* thisx)
 {
     return 0 == etch_apr_queue_lock(thisx->aprq)? 0: -1;
 }


 /**
  * release the lock guarding the queue
  */
 int etchqueue_unlock(etch_queue* thisx)
 {
     return 0 == etch_apr_queue_unlock(thisx->aprq)? 0: -1;
 }


 /**
  * acquire the lock guarding the queue if currently availbale
  */
 int etchqueue_trylock(etch_queue* thisx)
 {
     return 0 == etch_apr_queue_trylock(thisx->aprq)? 0: -1;
 }


 /* - - - - - - - - - -
  * i_iterable
  * - - - - - - - - - -
  */

 /*
  * etchqueue_iterable_first()
  * i_iterable first() implementation
  */
 int etchqueue_iterable_first(etch_iterator* iter)
 {
     etch_queue* etchq = NULL;
     if (!iter || !iter->collection)  return -1;
     etchq = iter->collection;
     if (!etchqueue_size(etchq)) return -1;

     iter->current_value = etchq->aprq->data[0];
     iter->ordinal = iter->current_value? 1: 0;
     return iter->ordinal? 0: -1;
 }


 /*
  * etchqueue_iterable_next()
  * i_iterable next() implementation
  * functions as first() if there is no current position.
  */
 int etchqueue_iterable_next(etch_iterator* iter)
 {
     etch_queue* etchq = iter? iter->collection: NULL;
     const int count = etchqueue_size(etchq);
     if (!count || !iter->ordinal) return -1;

     iter->current_value = etchq->aprq->data[iter->ordinal];
     iter->ordinal = iter->current_value? ++iter->ordinal: 0;
     return iter->ordinal? 0: -1;
 }


 /*
  * etchqueue_iterable_has_next()
  * i_iterable has_next() implementation.
  */
 int etchqueue_iterable_has_next(etch_iterator* iter)
 {
     etch_queue* etchq = iter? iter->collection: NULL;
     const int count = etchqueue_size(etchq);
     return count && iter->ordinal && (iter->ordinal <= count);
 }
	/* $Id$
	*
	* Licensed to the Apache Software Foundation (ASF) under one or more
	* contributor license agreements. See the NOTICE file distributed with
	* this work for additional information regarding copyright ownership.
	* The ASF licenses this file to you under the Apache License, Version
	* 2.0 (the "License"); you may not use this file except in compliance
	* with the License. You may obtain a copy of the License at
	*
	* http://www.apache.org/licenses/LICENSE-2.0
	*
	* Unless required by applicable law or agreed to in writing, software
	* distributed under the License is distributed on an "AS IS" BASIS,
	* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
	* See the License for the specific language governing permissions and
	* limitations under the License.
	*/

	/**
	* etch_queue.c
	*/

	#include "etch_queue.h"
	#include "etch_thread.h"
	#include "etch_log.h"
	#include "etch_mem.h"
	#include "etch_runtime.h"
	#include "etch_objecttypes.h"

	/*
	static const char* LOG_CATEGORY = "etch_queue";
	*/

	extern apr_pool_t* g_etch_main_pool;

	int destroy_etch_queue(void*);
	void etchqueue_clear(etch_queue*);
	int etchqueue_iterable_first(etch_iterator*);
	int etchqueue_iterable_next(etch_iterator*);
	int etchqueue_iterable_has_next(etch_iterator*);



	/**
	* new_queue()
	* etch_queue constructor
	*/
	etch_queue* new_queue(const int initialsize)
	{
	etch_queue* newq = NULL;
	etch_apr_queue_t* aprq = NULL;
	apr_pool_t* newsubpool = NULL;
	int result = -1, qsize = initialsize > 0? initialsize: ETCH_DEFQSIZE;

	do
	{

	// TODO: pool
	result = apr_pool_create(&newsubpool, g_etch_main_pool);
	//printf("2 creating apr pool %p\n",newsubpool);
	if (0 != result) break;
	/* set pool abort function */
	apr_pool_abort_set(etch_runtime_mem_abort, newsubpool);


	result = etch_apr_queue_create (&aprq, qsize, newsubpool);
	if (0 != result) break;

	newq = (etch_queue*) new_object(sizeof(etch_queue), ETCHTYPEB_ETCHQUEUE, CLASSID_ETCHQUEUE);

	newq->aprq = aprq;
	newq->subpool = newsubpool;
	newq->qcapacity = initialsize;
	((etch_object*)newq)->destroy = destroy_etch_queue;
	/* assume content to be etch objects owned by the queue */
	newq->is_readonly = FALSE;
	newq->content_type = ETCHQUEUE_CONTENT_OBJECT;

	new_iterable(&newq->iterable, NULL, etchqueue_iterable_first,
	etchqueue_iterable_next, etchqueue_iterable_has_next);

	result = 0;

	} while(0);

	if (0 != result)
	{
	if (newsubpool) {
	//printf("3 destroying apr pool %p\n",newsubpool);
	apr_pool_destroy(newsubpool);
	}
	}

	return newq;
	}


	/*
	* destroy_etch_queue()
	* etch_queue destructor
	*/
	int destroy_etch_queue(void* data)
	{
	etch_queue* queue = (etch_queue*)data;
	if (NULL == queue) return -1;

	if (-1 == etch_apr_queue_trylock(queue->aprq))
	return -1;
	else etch_apr_queue_unlock(queue->aprq);

	if (!is_etchobj_static_content(queue))
	{
	/* free etch-managed memory */
	etchqueue_clear(queue);

	/* free APR-managed memory - APR queue sets a callback such that
	* destroying the memory pool destroys the APR queue object */
	if (queue->subpool) {
	//printf("4 destroying apr pool %p\n",queue->subpool);
	apr_pool_destroy(queue->subpool);
	}

	queue->subpool = NULL;
	queue->aprq = NULL;
	}

	return destroy_objectex((etch_object*)queue);
	}


	/*
	* etchqueue_clear()
	* frees queue content memory.
	* this ensures the underlying queue is closed, so it is only invoked prior to
	* destruction of the queue in order to free any remaining queued etch objects.
	* all other memory associated with the queue, other than the shell object,
	* is managed by APR.
	*/
	void etchqueue_clear(etch_queue* thisx)
	{
	if (NULL == thisx \|\| NULL == thisx->aprq \|\| thisx->is_readonly) return;
	etchqueue_close(thisx, TRUE); /* close queue and notify all waiters */

	do
	{ void* qobj = NULL;
	queuecallback callback = thisx->freehook;
	int i = 0, is_freehandled = 0, result = 0;
	const int is_obj_content = thisx->content_type == ETCHQUEUE_CONTENT_OBJECT;

	while(1)
	{
	result = etchqueue_get_withwait (thisx, ETCHQUEUE_CLEARING_CLOSED_QUEUE, &qobj);
	if (0 != result) break;

	is_freehandled = callback? callback(i, qobj): FALSE;

	if (is_freehandled);
	else
	if (is_obj_content)
	((etch_object*)qobj)->destroy(qobj);
	else etch_free(qobj);
	}

	} while(0);
	}


	/**
	* etchqueue_size()
	* @return current queue depth
	* not thread-safe, caller should hold the mailbox queue lock
	*/
	int etchqueue_size(etch_queue* thisx)
	{
	return thisx && thisx->aprq? etch_apr_queue_size(thisx->aprq): 0;
	}


	/**
	* etchqueue_is_closed()
	* not thread-safe, caller should hold the mailbox queue lock
	*/
	int etchqueue_is_closed(etch_queue* thisx)
	{
	return thisx && thisx->aprq? thisx->aprq->terminated != 0: TRUE;
	}


	/**
	* etchqueue_is_full()
	* not thread-safe, caller should hold the mailbox queue lock
	*/
	int etchqueue_is_full(etch_queue* thisx)
	{
	return thisx && thisx->aprq? thisx->aprq->nelts == thisx->aprq->bounds: TRUE;
	}


	/**
	* etchqueue_close()
	* underlying implementation ensures operation atomicity
	*/
	int etchqueue_close(etch_queue* thisx, const int is_needlock)
	{
	int result = 0;

	if (!etchqueue_is_closed(thisx))
	{
	if (is_needlock)
	result = etch_apr_queue_term(thisx->aprq);
	else
	result = etch_apr_queue_unsafeclose(thisx->aprq);

	result = result == 0? 0: -1;
	}
	return result;
	}


	/**
	* etchqueue_put()
	* push specified item onto the queue. if the queue is full,
	* wait indefinitely until space becomes available.
	* @return 0 success, -1 error.
	*/
	int etchqueue_put(etch_queue* thisx, void* item)
	{
	const int result = etchqueue_put_withwait(thisx, ETCH_INFWAIT, item);
	return result;
	}


	/**
	* etchqueue_put_withwait()
	* push specified item onto the queue. if the queue is full,
	* waitms specified time interval until space becomes available.
	* @param waitms wait interval in milliseconds. specify ETCH_INFWAIT to wait
	* forever, ETCH_NOWAIT to not wait.
	* @return 0 success, -1 unsuccessful.
	*
	*/
	int etchqueue_put_withwait(etch_queue* thisx, const int waitms, void* item)
	{
	int result = 0, aprresult = 0;
	const int64 wait_usec = waitms < 0? -1: waitms * 1000;
	if (NULL == item \|\| etchqueue_is_closed(thisx)) return -1;

	/*
	* etch_apr_queue_push() takes care of notifying threads waiting on a
	* queue slot to become available, if any.
	*/
	aprresult = etch_apr_queue_push (thisx->aprq, wait_usec, item);

	switch(aprresult)
	{ case APR_SUCCESS: break;

	case APR_EAGAIN: /* timed out and queue still full */
	case APR_TIMEUP:
	result = ETCH_QUEUE_OPERATION_TIMEOUT;
	break;

	case APR_EINTR: /* wait interrupted and queue still full */
	result = ETCH_QUEUE_OPERATION_CANCELED;
	break;

	case APR_EOF: /* queue closed */
	default: /* some error */
	result = -1;
	}

	return result;
	}


	/**
	* etchqueue_get()
	* pop specified item off the queue and return it. if the queue is empty,
	* wait indefinitely for an item to arrive. popped item is returned in
	* out parameter.
	* @return 0 success, -1 error.
	*/
	int etchqueue_get(etch_queue* thisx, void** itemout)
	{
	const int result = etchqueue_get_withwait(thisx, ETCH_INFWAIT, itemout);
	return result;
	}


	/**
	* etchqueue_get_withwait()
	* pop specified item off the queue and return it. if the queue is empty,
	* wait specified time interval for an item to arrive. popped item is
	* returned in out parameter.
	* @param waitms wait interval in milliseconds. specify ETCH_INFWAIT to wait
	* forever, ETCH_NOWAIT to not wait, ETCHQUEUE_CLEARING_CLOSED_QUEUE to do a
	* get with no wait regardless of whether queue has been closed.
	* @return 0 success, -1 unsuccessful.
	*
	*/
	int etchqueue_get_withwait(etch_queue* thisx, const int waitms, void** itemout)
	{
	int result = 0, aprresult = 0;
	const int64 wait_usec = waitms < 0? waitms: waitms * 1000;

	if (etchqueue_is_closed(thisx))
	if (waitms != ETCHQUEUE_CLEARING_CLOSED_QUEUE)
	return -1;

	/*
	* etch_apr_queue_pop() takes care of notifying waiters if necessary
	*/
	aprresult = etch_apr_queue_pop (thisx->aprq, wait_usec, itemout);

	switch(aprresult)
	{ case APR_SUCCESS: break;

	case APR_EAGAIN: /* timed out and queue still full */
	case APR_TIMEUP:
	result = ETCH_QUEUE_OPERATION_TIMEOUT; break;

	case APR_EINTR: /* wait interrupted and queue still empty */
	result = ETCH_QUEUE_OPERATION_CANCELED; break;

	case APR_EOF: /* queue empty */
	result = ETCH_QUEUE_EOF; break;

	default: /* some error */
	result = -1;
	}

	return result;
	}


	/**
	* etchqueue_try_put()
	* @return 0 success, -1 unsuccessful.
	*
	*/
	int etchqueue_try_put(etch_queue* thisx, void* item)
	{
	const int result = etch_apr_queue_trypush(thisx->aprq, item);
	return result == 0? 0: -1;
	}


	/**
	* etchqueue_try_get()
	* @return 0 success, -1 unsuccessful.
	*/
	int etchqueue_try_get(etch_queue* thisx, void** itemout)
	{
	const int result = etch_apr_queue_trypop(thisx->aprq, itemout);
	return result == 0? 0: -1;
	}


	/**
	* etchqueue_notify_all()
	* wake up all waiters,
	* @return 0 success, -1 unsuccessful.
	*/
	int etchqueue_notify_all(etch_queue* thisx)
	{
	const int aprresult = etch_apr_queue_interrupt_all(thisx->aprq);
	return aprresult == 0? 0: -1;
	}


	/**
	* acquire the lock guarding the queue
	*/
	int etchqueue_lock(etch_queue* thisx)
	{
	return 0 == etch_apr_queue_lock(thisx->aprq)? 0: -1;
	}


	/**
	* release the lock guarding the queue
	*/
	int etchqueue_unlock(etch_queue* thisx)
	{
	return 0 == etch_apr_queue_unlock(thisx->aprq)? 0: -1;
	}


	/**
	* acquire the lock guarding the queue if currently availbale
	*/
	int etchqueue_trylock(etch_queue* thisx)
	{
	return 0 == etch_apr_queue_trylock(thisx->aprq)? 0: -1;
	}


	/* - - - - - - - - - -
	* i_iterable
	* - - - - - - - - - -
	*/

	/*
	* etchqueue_iterable_first()
	* i_iterable first() implementation
	*/
	int etchqueue_iterable_first(etch_iterator* iter)
	{
	etch_queue* etchq = NULL;
	if (!iter \|\| !iter->collection) return -1;
	etchq = iter->collection;
	if (!etchqueue_size(etchq)) return -1;

	iter->current_value = etchq->aprq->data[0];
	iter->ordinal = iter->current_value? 1: 0;
	return iter->ordinal? 0: -1;
	}


	/*
	* etchqueue_iterable_next()
	* i_iterable next() implementation
	* functions as first() if there is no current position.
	*/
	int etchqueue_iterable_next(etch_iterator* iter)
	{
	etch_queue* etchq = iter? iter->collection: NULL;
	const int count = etchqueue_size(etchq);
	if (!count \|\| !iter->ordinal) return -1;

	iter->current_value = etchq->aprq->data[iter->ordinal];
	iter->ordinal = iter->current_value? ++iter->ordinal: 0;
	return iter->ordinal? 0: -1;
	}


	/*
	* etchqueue_iterable_has_next()
	* i_iterable has_next() implementation.
	*/
	int etchqueue_iterable_has_next(etch_iterator* iter)
	{
	etch_queue* etchq = iter? iter->collection: NULL;
	const int count = etchqueue_size(etchq);
	return count && iter->ordinal && (iter->ordinal <= count);
	}