/**************************************************************************
 *
 * Copyright 2009 VMware, Inc.
 * All Rights Reserved.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sub license, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice (including the
 * next paragraph) shall be included in all copies or substantial portions
 * of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT.
 * IN NO EVENT SHALL VMWARE AND/OR ITS SUPPLIERS BE LIABLE FOR
 * ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 *
 **************************************************************************/


/**
 * Bin queue.  We'll use two queues.  One contains "full" bins which
 * are produced by the "setup" code.  The other contains "empty" bins
 * which are produced by the "rast" code when it finishes rendering a bin.
 */


#include "pipe/p_thread.h"
#include "util/u_memory.h"
#include "lp_bin_queue.h"



#define MAX_BINS 4


/**
 * A queue of bins
 */
struct lp_bins_queue
{
   /** XXX might use a linked list here somedone, but the list will
    * probably always be pretty short.
    */
   struct lp_bins *bins[MAX_BINS];
   unsigned size;

   pipe_condvar size_change;
   pipe_mutex mutex;
};



/** Allocate a new bins queue */
struct lp_bins_queue *
lp_bins_queue_create(void)
{
   struct lp_bins_queue *queue = CALLOC_STRUCT(lp_bins_queue);
   if (queue) {
      pipe_condvar_init(queue->size_change);
      pipe_mutex_init(queue->mutex);
   }
   return queue;
}


/** Delete a new bins queue */
void
lp_bins_queue_destroy(struct lp_bins_queue *queue)
{
   pipe_condvar_destroy(queue->size_change);
   pipe_mutex_destroy(queue->mutex);
}


/** Remove first lp_bins from head of queue */
struct lp_bins *
lp_bins_dequeue(struct lp_bins_queue *queue)
{
   struct lp_bins *bins;
   unsigned i;

   pipe_mutex_lock(queue->mutex);
   while (queue->size == 0) {
      pipe_condvar_wait(queue->size_change, queue->mutex);
   }

   assert(queue->size >= 1);

   /* get head */
   bins = queue->bins[0];

   /* shift entries */
   for (i = 0; i < queue->size - 1; i++) {
      queue->bins[i] = queue->bins[i + 1];
   }

   queue->size--;

   /* signal size change */
   pipe_condvar_signal(queue->size_change);

   pipe_mutex_unlock(queue->mutex);

   return bins;
}


/** Add an lp_bins to tail of queue */
void
lp_bins_enqueue(struct lp_bins_queue *queue, struct lp_bins *bins)
{
   pipe_mutex_lock(queue->mutex);

   assert(queue->size < MAX_BINS);

   /* debug: check that bins is not already in the queue */
   if (0) {
      unsigned i;
      for (i = 0; i < queue->size; i++) {
         assert(queue->bins[i] != bins);
      }
   }

   /* add to end */
   queue->bins[queue->size++] = bins;

   /* signal size change */
   pipe_condvar_signal(queue->size_change);

   pipe_mutex_unlock(queue->mutex);
}


/** Return number of entries in the queue */
unsigned
lp_bins_queue_size(struct lp_bins_queue *queue)
{
   unsigned sz;
   pipe_mutex_lock(queue->mutex);
   sz = queue->size;
   pipe_mutex_unlock(queue->mutex);
   return sz;
}


/** Wait until the queue as 'size' entries */
void
lp_bins_queue_wait_size(struct lp_bins_queue *queue, unsigned size)
{
   pipe_mutex_lock(queue->mutex);
   while (queue->size != size) {
      pipe_condvar_wait(queue->size_change, queue->mutex);
   }
   pipe_mutex_unlock(queue->mutex);
}