/*

 * Copyright © 2009,2010  Red Hat, Inc.

 * Copyright © 2010,2011,2013  Google, Inc.

 *

 *  This is part of HarfBuzz, a text shaping library.

 *

 * Permission is hereby granted, without written agreement and without

 * license or royalty fees, to use, copy, modify, and distribute this

 * software and its documentation for any purpose, provided that the

 * above copyright notice and the following two paragraphs appear in

 * all copies of this software.

 *

 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR

 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES

 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN

 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH

 * DAMAGE.

 *

 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,

 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND

 * FITNESS FOR A PARTICULAR PURPOSE.  THE SOFTWARE PROVIDED HEREUNDER IS

 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO

 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.

 *

 * Red Hat Author(s): Behdad Esfahbod

 * Google Author(s): Behdad Esfahbod

 */

#include "hb.hh"

#ifndef HB_NO_AAT_SHAPE

#include "hb-aat-map.hh"

#include "hb-aat-layout.hh"

#include "hb-aat-layout-feat-table.hh"

void hb_aat_map_builder_t::add_feature (const hb_feature_t &feature)

{

  if (!face->table.feat->has_data ()) return;

  if (feature.tag == HB_TAG ('a','a','l','t'))

  {

    if (!face->table.feat->exposes_feature (HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_ALTERNATIVES))

      return;

    feature_range_t *range = features.push();

    range->start = feature.start;

    range->end = feature.end;

    range->info.type = HB_AAT_LAYOUT_FEATURE_TYPE_CHARACTER_ALTERNATIVES;

    range->info.setting = (hb_aat_layout_feature_selector_t) feature.value;

    range->info.seq = features.length;

    range->info.is_exclusive = true;

    return;

  }

  const hb_aat_feature_mapping_t *mapping = hb_aat_layout_find_feature_mapping (feature.tag);

  if (!mapping) return;

  const AAT::FeatureName* feature_name = &face->table.feat->get_feature (mapping->aatFeatureType);

  if (!feature_name->has_data ())

  {

    /* Special case: Chain::compile_flags will fall back to the deprecated version of

     * small-caps if necessary, so we need to check for that possibility.

     * https://github.com/harfbuzz/harfbuzz/issues/2307 */

    if (mapping->aatFeatureType == HB_AAT_LAYOUT_FEATURE_TYPE_LOWER_CASE &&

  mapping->selectorToEnable == HB_AAT_LAYOUT_FEATURE_SELECTOR_LOWER_CASE_SMALL_CAPS)

    {

      feature_name = &face->table.feat->get_feature (HB_AAT_LAYOUT_FEATURE_TYPE_LETTER_CASE);

      if (!feature_name->has_data ()) return;

    }

    else return;

  }

  feature_range_t *range = features.push();

  range->start = feature.start;

  range->end = feature.end;

  range->info.type = mapping->aatFeatureType;

  range->info.setting = feature.value ? mapping->selectorToEnable : mapping->selectorToDisable;

  range->info.seq = features.length;

  range->info.is_exclusive = feature_name->is_exclusive ();

}

void

hb_aat_map_builder_t::compile (hb_aat_map_t  &m)

{

  /* Compute active features per range, and compile each. */

  if (!features.length)

  {

    hb_aat_layout_compile_map (this, &m);

    return;

  }

  /* Sort features by start/end events. */

  hb_vector_t<feature_event_t> feature_events;

  feature_events.alloc_exact (features.length * 2 + 1);

  for (unsigned int i = 0; i < features.length; i++)

  {

    auto &feature = features.arrayZ[i];

    if (feature.start == feature.end)

      continue;

    feature_event_t *event;

    event = feature_events.push ();

    event->index = feature.start;

    event->start = true;

    event->feature = feature.info;

    event = feature_events.push ();

    event->index = feature.end;

    event->start = false;

    event->feature = feature.info;

  }

  feature_events.qsort ();

  /* Add a strategic final event. */

  {

    feature_info_t feature;

    feature.seq = features.length + 1;

    feature_event_t *event = feature_events.push ();

    event->index = -1; /* This value does magic. */

    event->start = false;

    event->feature = feature;

  }

  /* Scan events and save features for each range. */

  hb_sorted_vector_t<feature_info_t> active_features;

  unsigned int last_index = 0;

  for (unsigned int i = 0; i < feature_events.length; i++)

  {

    feature_event_t *event = &feature_events[i];

    if (event->index != last_index)

    {

      /* Save a snapshot of active features and the range. */

      /* Sort features and merge duplicates */

      current_features = active_features;

      range_first = last_index;

      range_last = event->index - 1;

      if (current_features.length)

      {

  current_features.qsort ();

  unsigned int j = 0;

  for (unsigned int i = 1; i < current_features.length; i++)

    if (current_features.arrayZ[i].type != current_features.arrayZ[j].type ||

        /* Nonexclusive feature selectors come in even/odd pairs to turn a setting on/off

         * respectively, so we mask out the low-order bit when checking for "duplicates"

         * (selectors referring to the same feature setting) here. */

        (!current_features.arrayZ[i].is_exclusive && ((current_features.arrayZ[i].setting & ~1) != (current_features.arrayZ[j].setting & ~1))))

      current_features.arrayZ[++j] = current_features.arrayZ[i];

  current_features.shrink (j + 1);

      }

      hb_aat_layout_compile_map (this, &m);

      last_index = event->index;

    }

    if (event->start)

    {

      active_features.push (event->feature);

    } else {

      feature_info_t *feature = active_features.lsearch (event->feature);

      if (feature)

  active_features.remove_ordered (feature - active_features.arrayZ);

    }

  }

  for (auto &chain_flags : m.chain_flags)

    // With our above setup this value is one less than desired; adjust it.

    chain_flags.tail().cluster_last = HB_FEATURE_GLOBAL_END;

}

#endif