harfbuzz/src/hb-shape-plan.cc

/*
 * Copyright © 2012  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.
 *
 * Google Author(s): Behdad Esfahbod
 */

#include "hb.hh"
#include "hb-shape-plan.hh"
#include "hb-shaper.hh"
#include "hb-font.hh"
#include "hb-buffer.hh"


/**
 * SECTION:hb-shape-plan
 * @title: hb-shape-plan
 * @short_description: Object representing a shaping plan
 * @include: hb.h
 *
 * Shape plans are not used for shaping directly, but can be access to query
 * certain information about how shaping will perform given a set of input
 * parameters (script, language, direction, features, etc.)
 * Most client would not need to deal with shape plans directly.
 **/


static void
hb_shape_plan_choose_shaper (hb_shape_plan_t    *shape_plan,
			     const hb_feature_t *user_features,
			     unsigned int        num_user_features,
			     const int          *coords,
			     unsigned int        num_coords,
			     const char * const *shaper_list)
{
  DEBUG_MSG_FUNC (SHAPE_PLAN, shape_plan,
		  "num_features=%d num_coords=%d shaper_list=%p",
		  num_user_features,
		  num_coords,
		  shaper_list);

  const hb_shaper_pair_static_t *shapers = _hb_shapers_get ();

#define HB_SHAPER_PLAN(shaper) \
	HB_STMT_START { \
	  if (hb_##shaper##_shaper_face_data_ensure (shape_plan->face_unsafe)) \
	  { \
	    shape_plan->shaper_func = _hb_##shaper##_shape; \
	    shape_plan->shaper_name = #shaper; \
	    return; \
	  } \
	} HB_STMT_END

  if (likely (!shaper_list)) {
    for (unsigned int i = 0; i < HB_SHAPERS_COUNT; i++)
      if (false)
	;
#define HB_SHAPER_IMPLEMENT(shaper) \
      else if (shapers[i].func == _hb_##shaper##_shape) \
	HB_SHAPER_PLAN (shaper);
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT
  } else {
    for (; *shaper_list; shaper_list++)
      if (false)
	;
#define HB_SHAPER_IMPLEMENT(shaper) \
      else if (0 == strcmp (*shaper_list, #shaper)) \
	HB_SHAPER_PLAN (shaper);
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT
  }

#undef HB_SHAPER_PLAN
}


/*
 * hb_shape_plan_t
 */


/**
 * hb_shape_plan_create: (Xconstructor)
 * @face: 
 * @props: 
 * @user_features: (array length=num_user_features):
 * @num_user_features: 
 * @shaper_list: (array zero-terminated=1):
 *
 * 
 *
 * Return value: (transfer full):
 *
 * Since: 0.9.7
 **/
hb_shape_plan_t *
hb_shape_plan_create (hb_face_t                     *face,
		      const hb_segment_properties_t *props,
		      const hb_feature_t            *user_features,
		      unsigned int                   num_user_features,
		      const char * const            *shaper_list)
{
  return hb_shape_plan_create2 (face, props,
				user_features, num_user_features,
				nullptr, 0,
				shaper_list);
}

hb_shape_plan_t *
hb_shape_plan_create2 (hb_face_t                     *face,
		       const hb_segment_properties_t *props,
		       const hb_feature_t            *user_features,
		       unsigned int                   num_user_features,
		       const int                     *orig_coords,
		       unsigned int                   num_coords,
		       const char * const            *shaper_list)
{
  DEBUG_MSG_FUNC (SHAPE_PLAN, nullptr,
		  "face=%p num_features=%d num_coords=%d shaper_list=%p",
		  face,
		  num_user_features,
		  num_coords,
		  shaper_list);

  hb_shape_plan_t *shape_plan;
  hb_feature_t *features = nullptr;
  int *coords = nullptr;

  if (unlikely (!props))
    goto bail;
  if (num_user_features && !(features = (hb_feature_t *) calloc (num_user_features, sizeof (hb_feature_t))))
    goto bail;
  if (num_coords && !(coords = (int *) calloc (num_coords, sizeof (int))))
    goto bail;
  if (!(shape_plan = hb_object_create<hb_shape_plan_t> ()))
    goto bail;

  assert (props->direction != HB_DIRECTION_INVALID);

  if (unlikely (!face))
    face = hb_face_get_empty ();
  hb_face_make_immutable (face);

  shape_plan->face_unsafe = face;
  shape_plan->props = *props;
  shape_plan->num_user_features = num_user_features;
  shape_plan->user_features = features;
  if (num_user_features)
    memcpy (features, user_features, num_user_features * sizeof (hb_feature_t));
  shape_plan->num_coords = num_coords;
  shape_plan->coords = coords;
  if (num_coords)
    memcpy (coords, orig_coords, num_coords * sizeof (int));
  shape_plan->custom_shaper_list = shaper_list;
  hb_shape_plan_choose_shaper (shape_plan,
			       user_features, num_user_features,
			       coords, num_coords,
			       shaper_list);

  if (unlikely (!shape_plan->ot.init0 (face,
				       props,
				       user_features,
				       num_user_features,
				       coords,
				       num_coords)))
    goto bail;

  return shape_plan;

bail:
  free (coords);
  free (features);
  return hb_shape_plan_get_empty ();
}

/**
 * hb_shape_plan_get_empty:
 *
 * 
 *
 * Return value: (transfer full):
 *
 * Since: 0.9.7
 **/
hb_shape_plan_t *
hb_shape_plan_get_empty (void)
{
  return const_cast<hb_shape_plan_t *> (&Null(hb_shape_plan_t));
}

/**
 * hb_shape_plan_reference: (skip)
 * @shape_plan: a shape plan.
 *
 * 
 *
 * Return value: (transfer full):
 *
 * Since: 0.9.7
 **/
hb_shape_plan_t *
hb_shape_plan_reference (hb_shape_plan_t *shape_plan)
{
  return hb_object_reference (shape_plan);
}

/**
 * hb_shape_plan_destroy: (skip)
 * @shape_plan: a shape plan.
 *
 * 
 *
 * Since: 0.9.7
 **/
void
hb_shape_plan_destroy (hb_shape_plan_t *shape_plan)
{
  if (!hb_object_destroy (shape_plan)) return;

  shape_plan->ot.fini ();

  free (shape_plan->user_features);
  free (shape_plan->coords);

  free (shape_plan);
}

/**
 * hb_shape_plan_set_user_data: (skip)
 * @shape_plan: a shape plan.
 * @key: 
 * @data: 
 * @destroy: 
 * @replace: 
 *
 * 
 *
 * Return value: 
 *
 * Since: 0.9.7
 **/
hb_bool_t
hb_shape_plan_set_user_data (hb_shape_plan_t    *shape_plan,
			     hb_user_data_key_t *key,
			     void *              data,
			     hb_destroy_func_t   destroy,
			     hb_bool_t           replace)
{
  return hb_object_set_user_data (shape_plan, key, data, destroy, replace);
}

/**
 * hb_shape_plan_get_user_data: (skip)
 * @shape_plan: a shape plan.
 * @key: 
 *
 * 
 *
 * Return value: (transfer none):
 *
 * Since: 0.9.7
 **/
void *
hb_shape_plan_get_user_data (hb_shape_plan_t    *shape_plan,
			     hb_user_data_key_t *key)
{
  return hb_object_get_user_data (shape_plan, key);
}


/**
 * hb_shape_plan_execute:
 * @shape_plan: a shape plan.
 * @font: a font.
 * @buffer: a buffer.
 * @features: (array length=num_features):
 * @num_features: 
 *
 * 
 *
 * Return value: 
 *
 * Since: 0.9.7
 **/
hb_bool_t
hb_shape_plan_execute (hb_shape_plan_t    *shape_plan,
		       hb_font_t          *font,
		       hb_buffer_t        *buffer,
		       const hb_feature_t *features,
		       unsigned int        num_features)
{
  DEBUG_MSG_FUNC (SHAPE_PLAN, shape_plan,
		  "num_features=%d shaper_func=%p, shaper_name=%s",
		  num_features,
		  shape_plan->shaper_func,
		  shape_plan->shaper_name);

  if (unlikely (!buffer->len))
    return true;

  assert (!hb_object_is_immutable (buffer));
  assert (buffer->content_type == HB_BUFFER_CONTENT_TYPE_UNICODE);

  if (unlikely (hb_object_is_inert (shape_plan)))
    return false;

  assert (shape_plan->face_unsafe == font->face);
  assert (hb_segment_properties_equal (&shape_plan->props, &buffer->props));

#define HB_SHAPER_EXECUTE(shaper) \
	HB_STMT_START { \
	  return hb_##shaper##_shaper_font_data_ensure (font) && \
		 _hb_##shaper##_shape (shape_plan, font, buffer, features, num_features); \
	} HB_STMT_END

  if (false)
    ;
#define HB_SHAPER_IMPLEMENT(shaper) \
  else if (shape_plan->shaper_func == _hb_##shaper##_shape) \
    HB_SHAPER_EXECUTE (shaper);
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT

#undef HB_SHAPER_EXECUTE

  return false;
}


/*
 * caching
 */

#if 0
static unsigned int
hb_shape_plan_hash (const hb_shape_plan_t *shape_plan)
{
  return hb_segment_properties_hash (&shape_plan->props) +
	 shape_plan->custom_shaper_list ? (intptr_t) shape_plan->shaper_func : 0;
}
#endif

/* User-feature caching is currently somewhat dumb:
 * it only finds matches where the feature array is identical,
 * not cases where the feature lists would be compatible for plan purposes
 * but have different ranges, for example.
 */
struct hb_shape_plan_proposal_t
{
  const hb_segment_properties_t  props;
  const hb_feature_t            *user_features;
  unsigned int                   num_user_features;
  const int                     *coords;
  unsigned int                   num_coords;
  bool                           custom_shaper_list;
  hb_shape_func_t               *shaper_func;
};

static inline hb_bool_t
hb_shape_plan_user_features_match (const hb_shape_plan_t          *shape_plan,
				   const hb_shape_plan_proposal_t *proposal)
{
  if (proposal->num_user_features != shape_plan->num_user_features)
    return false;
  for (unsigned int i = 0, n = proposal->num_user_features; i < n; i++)
    if (proposal->user_features[i].tag   != shape_plan->user_features[i].tag   ||
        proposal->user_features[i].value != shape_plan->user_features[i].value ||
        proposal->user_features[i].start != shape_plan->user_features[i].start ||
        proposal->user_features[i].end   != shape_plan->user_features[i].end)
      return false;
  return true;
}

static inline hb_bool_t
hb_shape_plan_coords_match (const hb_shape_plan_t          *shape_plan,
			    const hb_shape_plan_proposal_t *proposal)
{
  if (proposal->num_coords != shape_plan->num_coords)
    return false;
  for (unsigned int i = 0, n = proposal->num_coords; i < n; i++)
    if (proposal->coords[i] != shape_plan->coords[i])
      return false;
  return true;
}

static hb_bool_t
hb_shape_plan_matches (const hb_shape_plan_t          *shape_plan,
		       const hb_shape_plan_proposal_t *proposal)
{
  return hb_segment_properties_equal (&shape_plan->props, &proposal->props) &&
	 hb_shape_plan_user_features_match (shape_plan, proposal) &&
	 hb_shape_plan_coords_match (shape_plan, proposal) &&
	 ((!shape_plan->custom_shaper_list && !proposal->custom_shaper_list) ||
	  (shape_plan->shaper_func == proposal->shaper_func));
}

static inline hb_bool_t
hb_non_global_user_features_present (const hb_feature_t *user_features,
				     unsigned int        num_user_features)
{
  while (num_user_features) {
    if (user_features->start != 0 || user_features->end != (unsigned int) -1)
      return true;
    num_user_features--;
    user_features++;
  }
  return false;
}

static inline hb_bool_t
hb_coords_present (const int *coords HB_UNUSED,
		   unsigned int num_coords)
{
  return num_coords != 0;
}

/**
 * hb_shape_plan_create_cached:
 * @face: 
 * @props: 
 * @user_features: (array length=num_user_features):
 * @num_user_features: 
 * @shaper_list: (array zero-terminated=1):
 *
 * 
 *
 * Return value: (transfer full):
 *
 * Since: 0.9.7
 **/
hb_shape_plan_t *
hb_shape_plan_create_cached (hb_face_t                     *face,
			     const hb_segment_properties_t *props,
			     const hb_feature_t            *user_features,
			     unsigned int                   num_user_features,
			     const char * const            *shaper_list)
{
  return hb_shape_plan_create_cached2 (face, props,
				       user_features, num_user_features,
				       nullptr, 0,
				       shaper_list);
}

hb_shape_plan_t *
hb_shape_plan_create_cached2 (hb_face_t                     *face,
			      const hb_segment_properties_t *props,
			      const hb_feature_t            *user_features,
			      unsigned int                   num_user_features,
			      const int                     *coords,
			      unsigned int                   num_coords,
			      const char * const            *shaper_list)
{
  DEBUG_MSG_FUNC (SHAPE_PLAN, nullptr,
		  "face=%p num_features=%d shaper_list=%p",
		  face,
		  num_user_features,
		  shaper_list);

  hb_shape_plan_proposal_t proposal =
  {
    *props,
    user_features,
    num_user_features,
    coords,
    num_coords,
    shaper_list,
    nullptr
  };

  if (shaper_list)
  {
    /* Choose shaper.  Adapted from hb_shape_plan_choose_shaper().
     * Must choose shaper exactly the same way as that function. */
    for (const char * const *shaper_item = shaper_list; *shaper_item; shaper_item++)
      if (false)
	;
#define HB_SHAPER_IMPLEMENT(shaper) \
      else if (0 == strcmp (*shaper_item, #shaper) && \
	       hb_##shaper##_shaper_face_data_ensure (face)) \
      { \
	proposal.shaper_func = _hb_##shaper##_shape; \
	break; \
      }
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT

    if (unlikely (!proposal.shaper_func))
      return hb_shape_plan_get_empty ();
  }


retry:
  hb_face_t::plan_node_t *cached_plan_nodes = face->shape_plans;

  /* Don't look for plan in the cache if there were variation coordinates XXX Fix me. */
  if (!hb_coords_present (coords, num_coords))
    for (hb_face_t::plan_node_t *node = cached_plan_nodes; node; node = node->next)
      if (hb_shape_plan_matches (node->shape_plan, &proposal))
      {
        DEBUG_MSG_FUNC (SHAPE_PLAN, node->shape_plan, "fulfilled from cache");
        return hb_shape_plan_reference (node->shape_plan);
      }

  /* Not found. */
  hb_shape_plan_t *shape_plan = hb_shape_plan_create2 (face, props,
						       user_features, num_user_features,
						       coords, num_coords,
						       shaper_list);

  /* Don't add to the cache if face is inert. */
  if (unlikely (hb_object_is_inert (face)))
    return shape_plan;

  /* Don't add the plan to the cache if there were user features with non-global ranges */
  if (hb_non_global_user_features_present (user_features, num_user_features))
    return shape_plan;
  /* Don't add the plan to the cache if there were variation coordinates XXX Fix me. */
  if (hb_coords_present (coords, num_coords))
    return shape_plan;

  hb_face_t::plan_node_t *node = (hb_face_t::plan_node_t *) calloc (1, sizeof (hb_face_t::plan_node_t));
  if (unlikely (!node))
    return shape_plan;

  node->shape_plan = shape_plan;
  node->next = cached_plan_nodes;

  if (unlikely (!face->shape_plans.cmpexch (cached_plan_nodes, node)))
  {
    hb_shape_plan_destroy (shape_plan);
    free (node);
    goto retry;
  }
  DEBUG_MSG_FUNC (SHAPE_PLAN, shape_plan, "inserted into cache");

  return hb_shape_plan_reference (shape_plan);
}

/**
 * hb_shape_plan_get_shaper:
 * @shape_plan: a shape plan.
 *
 * 
 *
 * Return value: (transfer none):
 *
 * Since: 0.9.7
 **/
const char *
hb_shape_plan_get_shaper (hb_shape_plan_t *shape_plan)
{
  return shape_plan->shaper_name;
}