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-private.hh"

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

#define HB_SHAPER_IMPLEMENT(shaper) \
	HB_SHAPER_DATA_ENSURE_DECLARE(shaper, face) \
	HB_SHAPER_DATA_ENSURE_DECLARE(shaper, font)
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT


void
hb_shape_plan_plan (hb_shape_plan_t    *shape_plan,
		    const hb_feature_t *user_features,
		    unsigned int        num_user_features,
		    const char * const *shaper_list)
{
  const hb_shaper_pair_t *shapers = _hb_shapers_get ();

#define HB_SHAPER_PLAN(shaper) \
	HB_STMT_START { \
	  if (hb_##shaper##_shaper_face_data_ensure (shape_plan->face)) { \
	    HB_SHAPER_DATA (shaper, shape_plan) = \
	      HB_SHAPER_DATA_CREATE_FUNC (shaper, shape_plan) (shape_plan, user_features, num_user_features); \
	    shape_plan->shaper_func = _hb_##shaper##_shape; \
	    return; \
	  } \
	} HB_STMT_END

  if (likely (!shaper_list)) {
    for (unsigned int i = 0; i < HB_SHAPERS_COUNT; i++)
      if (0)
	;
#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 (0)
	;
#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_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)
{
  assert (props->direction != HB_DIRECTION_INVALID);

  hb_shape_plan_t *shape_plan;

  if (unlikely (!face))
    face = hb_face_get_empty ();
  if (unlikely (!props || hb_object_is_inert (face)))
    return hb_shape_plan_get_empty ();
  if (!(shape_plan = hb_object_create<hb_shape_plan_t> ()))
    return hb_shape_plan_get_empty ();

  hb_face_make_immutable (face);
  shape_plan->default_shaper_list = shaper_list == NULL;
  shape_plan->face = hb_face_reference (face);
  shape_plan->props = *props;

  hb_shape_plan_plan (shape_plan, user_features, num_user_features, shaper_list);

  return shape_plan;
}

hb_shape_plan_t *
hb_shape_plan_get_empty (void)
{
  static const hb_shape_plan_t _hb_shape_plan_nil = {
    HB_OBJECT_HEADER_STATIC,

    true, /* default_shaper_list */
    NULL, /* face */
    _HB_BUFFER_PROPS_DEFAULT, /* props */

    NULL, /* shaper_func */

    {
#define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_INVALID,
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT
    }
  };

  return const_cast<hb_shape_plan_t *> (&_hb_shape_plan_nil);
}

hb_shape_plan_t *
hb_shape_plan_reference (hb_shape_plan_t *shape_plan)
{
  return hb_object_reference (shape_plan);
}

void
hb_shape_plan_destroy (hb_shape_plan_t *shape_plan)
{
  if (!hb_object_destroy (shape_plan)) return;

#define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_DESTROY(shaper, shape_plan);
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT

  free (shape_plan);
}


hb_bool_t
hb_shape_plan_execute (hb_shape_plan      *shape_plan,
		       hb_font_t          *font,
		       hb_buffer_t        *buffer,
		       const hb_feature_t *features,
		       unsigned int        num_features)
{
  if (unlikely (shape_plan->face != font->face))
    return false;

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

  if (0)
    ;
#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 long
hb_shape_plan_hash (const hb_shape_plan_t *shape_plan)
{
  return hb_segment_properties_hash (&shape_plan->props) +
	 shape_plan->default_shaper_list ? 0 : (long) shape_plan->shaper_func;
}
#endif

/* TODO no user-feature caching for now. */
struct hb_shape_plan_proposal_t
{
  const hb_segment_properties_t  props;
  const char * const            *shaper_list;
  hb_shape_func_t               *shaper_func;
};

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) &&
	 ((shape_plan->default_shaper_list && proposal->shaper_list == NULL) ||
	  (shape_plan->shaper_func == proposal->shaper_func));
}

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)
{
  if (num_user_features)
    return hb_shape_plan_create (face, props, user_features, num_user_features, shaper_list);

  hb_shape_plan_proposal_t proposal = {
    *props,
    shaper_list,
    NULL
  };

  if (shaper_list) {
    /* Choose shaper.  Adapted from hb_shape_plan_plan(). */
#define HB_SHAPER_PLAN(shaper) \
	  HB_STMT_START { \
	    if (hb_##shaper##_shaper_face_data_ensure (face)) \
	      proposal.shaper_func = _hb_##shaper##_shape; \
	  } HB_STMT_END

    for (const char * const *shaper_item = shaper_list; *shaper_item; shaper_item++)
      if (0)
	;
#define HB_SHAPER_IMPLEMENT(shaper) \
      else if (0 == strcmp (*shaper_item, #shaper)) \
	HB_SHAPER_PLAN (shaper);
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT

#undef HB_SHAPER_PLAN

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


retry:
  hb_face_t::plan_node_t *cached_plan_nodes = (hb_face_t::plan_node_t *) hb_atomic_ptr_get (&face->shape_plans);
  for (hb_face_t::plan_node_t *node = cached_plan_nodes; node; node = node->next)
    if (hb_shape_plan_matches (node->shape_plan, &proposal))
      return hb_shape_plan_reference (node->shape_plan);

  /* Not found. */

  hb_shape_plan_t *shape_plan = hb_shape_plan_create (face, props, user_features, num_user_features, shaper_list);

  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 (!hb_atomic_ptr_cmpexch (&face->shape_plans, cached_plan_nodes, node)) {
    hb_shape_plan_destroy (shape_plan);
    free (node);
    goto retry;
  }

  /* Release our reference on face. */
  hb_face_destroy (face);

  return hb_shape_plan_reference (shape_plan);
}