/* gtksizerequest.c
 * Copyright (C) 2007-2010 Openismus GmbH
 *
 * Authors:
 *      Mathias Hasselmann <mathias@openismus.com>
 *      Tristan Van Berkom <tristan.van.berkom@gmail.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library. If not, see <http://www.gnu.org/licenses/>.
 */

#include <config.h>

#include "gtksizerequestcacheprivate.h"

#include <string.h>

void
_gtk_size_request_cache_init (SizeRequestCache *cache)
{
  memset (cache, 0, sizeof (SizeRequestCache));
}

static void
free_sizes (SizeRequest **sizes)
{
  gint i;

  for (i = 0; i < GTK_SIZE_REQUEST_CACHED_SIZES && sizes[i] != NULL; i++)
    g_slice_free (SizeRequest, sizes[i]);
      
  g_slice_free1 (sizeof (SizeRequest *) * GTK_SIZE_REQUEST_CACHED_SIZES, sizes);
}

void
_gtk_size_request_cache_free (SizeRequestCache *cache)
{
  if (cache->widths)
    free_sizes (cache->widths);
  if (cache->heights)
    free_sizes (cache->heights);
}

void
_gtk_size_request_cache_clear (SizeRequestCache *cache)
                               
{
  _gtk_size_request_cache_free (cache);
  _gtk_size_request_cache_init (cache);
}

void
_gtk_size_request_cache_commit (SizeRequestCache *cache,
                                GtkOrientation    orientation,
                                gint              for_size,
                                gint              minimum_size,
                                gint              natural_size)
{
  SizeRequest      **cached_sizes;
  guint              i, n_sizes;

  /* First handle caching of the base requests */
  if (for_size < 0)
    {
      if (orientation == GTK_ORIENTATION_HORIZONTAL)
	{
	  cache->cached_width.minimum_size = minimum_size;
	  cache->cached_width.natural_size = natural_size;
	  cache->cached_base_width = TRUE;
	}
      else
	{
	  cache->cached_height.minimum_size = minimum_size;
	  cache->cached_height.natural_size = natural_size;
	  cache->cached_base_height = TRUE;
	}
      return;
    }

  /* Check if the minimum_size and natural_size is already
   * in the cache and if this result can be used to extend
   * that cache entry 
   */
  if (orientation == GTK_ORIENTATION_HORIZONTAL)
    {
      cached_sizes = cache->widths;
      n_sizes = cache->cached_widths;
    }
  else
    {
      cached_sizes = cache->heights;
      n_sizes = cache->cached_heights;
    }

  for (i = 0; i < n_sizes; i++)
    {
      if (cached_sizes[i]->cached_size.minimum_size == minimum_size &&
	  cached_sizes[i]->cached_size.natural_size == natural_size)
	{
	  cached_sizes[i]->lower_for_size = MIN (cached_sizes[i]->lower_for_size, for_size);
	  cached_sizes[i]->upper_for_size = MAX (cached_sizes[i]->upper_for_size, for_size);
	  return;
	}
    }

  /* If not found, pull a new size from the cache, the returned size cache
   * will immediately be used to cache the new computed size so we go ahead
   * and increment the last_cached_width/height right away */
  if (orientation == GTK_ORIENTATION_HORIZONTAL)
    {
      if (cache->cached_widths < GTK_SIZE_REQUEST_CACHED_SIZES)
	{
	  cache->cached_widths++;
	  cache->last_cached_width = cache->cached_widths - 1;
	}
      else
	{
	  if (++cache->last_cached_width == GTK_SIZE_REQUEST_CACHED_SIZES)
	    cache->last_cached_width = 0;
	}

      if (!cache->widths)
	cache->widths = g_slice_alloc0 (sizeof (SizeRequest *) * GTK_SIZE_REQUEST_CACHED_SIZES);

      if (!cache->widths[cache->last_cached_width])
	cache->widths[cache->last_cached_width] = g_slice_new (SizeRequest);

      cache->widths[cache->last_cached_width]->lower_for_size = for_size;
      cache->widths[cache->last_cached_width]->upper_for_size = for_size;
      cache->widths[cache->last_cached_width]->cached_size.minimum_size = minimum_size;
      cache->widths[cache->last_cached_width]->cached_size.natural_size = natural_size;
    }
  else /* GTK_ORIENTATION_VERTICAL */
    {
      if (cache->cached_heights < GTK_SIZE_REQUEST_CACHED_SIZES)
	{
	  cache->cached_heights++;
	  cache->last_cached_height = cache->cached_heights - 1;
	}
      else
	{
	  if (++cache->last_cached_height == GTK_SIZE_REQUEST_CACHED_SIZES)
	    cache->last_cached_height = 0;
	}

      if (!cache->heights)
	cache->heights = g_slice_alloc0 (sizeof (SizeRequest *) * GTK_SIZE_REQUEST_CACHED_SIZES);

      if (!cache->heights[cache->last_cached_height])
	cache->heights[cache->last_cached_height] = g_slice_new (SizeRequest);

      cache->heights[cache->last_cached_height]->lower_for_size = for_size;
      cache->heights[cache->last_cached_height]->upper_for_size = for_size;
      cache->heights[cache->last_cached_height]->cached_size.minimum_size = minimum_size;
      cache->heights[cache->last_cached_height]->cached_size.natural_size = natural_size;
    }
}

/* looks for a cached size request for this for_size.
 *
 * Note that this caching code was originally derived from
 * the Clutter toolkit but has evolved for other GTK+ requirements.
 */
gboolean
_gtk_size_request_cache_lookup (SizeRequestCache *cache,
                                GtkOrientation    orientation,
                                gint              for_size,
                                gint             *minimum,
                                gint             *natural)
{
  CachedSize *result = NULL;

  if (for_size < 0)
    {
      if (orientation == GTK_ORIENTATION_HORIZONTAL)
	{
          if (cache->cached_base_width)
	    result = &cache->cached_width;
	}
      else
	{
	  if (cache->cached_base_height)
	    result = &cache->cached_height;
	}
    }
  else
    {
      SizeRequest      **cached_sizes;
      guint              i, n_sizes;

      if (orientation == GTK_ORIENTATION_HORIZONTAL)
        {
          cached_sizes = cache->widths;
          n_sizes      = cache->cached_widths;
        }
      else
        {
          cached_sizes = cache->heights;
          n_sizes      = cache->cached_heights;
        }

      /* Search for an already cached size */
      for (i = 0; i < n_sizes; i++)
        {
          if (cached_sizes[i]->lower_for_size <= for_size &&
              cached_sizes[i]->upper_for_size >= for_size)
            {
              result = &cached_sizes[i]->cached_size;
              break;
            }
        }
    }

  if (result)
    {
      *minimum = result->minimum_size;
      *natural = result->natural_size;
      return TRUE;
    }
  else
    return FALSE;
}