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 /*

  * 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

  */

 #ifndef HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH

 #define HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH

 #include "hb-private.hh"

 #include "hb-ot-shape-private.hh"

 #include "hb-ot-layout-gsub-table.hh"

 static const hb_tag_t arabic_fallback_features[] =

 {

   HB_TAG('i','n','i','t'),

   HB_TAG('m','e','d','i'),

   HB_TAG('f','i','n','a'),

   HB_TAG('i','s','o','l'),

   HB_TAG('r','l','i','g'),

 };

 /* Same order as the fallback feature array */

 enum {

   FALLBACK_INIT,

   FALLBACK_MEDI,

   FALLBACK_FINA,

   FALLBACK_ISOL,

   FALLBACK_RLIG,

   ARABIC_NUM_FALLBACK_FEATURES

 };

 static OT::SubstLookup *

 arabic_fallback_synthesize_lookup_single (const hb_ot_shape_plan_t *plan HB_UNUSED,

 					  hb_font_t *font,

 					  unsigned int feature_index)

 {

   OT::GlyphID glyphs[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1];

   OT::GlyphID substitutes[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1];

   unsigned int num_glyphs = 0;

   /* Populate arrays */

   for (hb_codepoint_t u = SHAPING_TABLE_FIRST; u < SHAPING_TABLE_LAST + 1; u++)

   {

     hb_codepoint_t s = shaping_table[u - SHAPING_TABLE_FIRST][feature_index];

     hb_codepoint_t u_glyph, s_glyph;

     if (!s ||

 	!hb_font_get_glyph (font, u, 0, &u_glyph) ||

 	!hb_font_get_glyph (font, s, 0, &s_glyph) ||

 	u_glyph == s_glyph ||

 	u_glyph > 0xFFFF || s_glyph > 0xFFFF)

       continue;

     glyphs[num_glyphs].set (u_glyph);

     substitutes[num_glyphs].set (s_glyph);

     num_glyphs++;

   }

   /* Bubble-sort!

    * May not be good-enough for presidential candidate interviews, but good-enough for us... */

   hb_bubble_sort (&glyphs[0], num_glyphs, OT::GlyphID::cmp, &substitutes[0]);

   OT::Supplier<OT::GlyphID> glyphs_supplier      (glyphs, num_glyphs);

   OT::Supplier<OT::GlyphID> substitutes_supplier (substitutes, num_glyphs);

   /* Each glyph takes four bytes max, and there's some overhead. */

   char buf[(SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1) * 4 + 128];

   OT::hb_serialize_context_t c (buf, sizeof (buf));

   OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> ();

   bool ret = lookup->serialize_single (&c,

 				       OT::LookupFlag::IgnoreMarks,

 				       glyphs_supplier,

 				       substitutes_supplier,

 				       num_glyphs);

   c.end_serialize ();

   /* TODO sanitize the results? */

   return ret ? c.copy<OT::SubstLookup> () : NULL;

 }

 static OT::SubstLookup *

 arabic_fallback_synthesize_lookup_ligature (const hb_ot_shape_plan_t *plan HB_UNUSED,

 					    hb_font_t *font)

 {

   OT::GlyphID first_glyphs[ARRAY_LENGTH_CONST (ligature_table)];

   unsigned int first_glyphs_indirection[ARRAY_LENGTH_CONST (ligature_table)];

   unsigned int ligature_per_first_glyph_count_list[ARRAY_LENGTH_CONST (first_glyphs)];

   unsigned int num_first_glyphs = 0;

   /* We know that all our ligatures are 2-component */

   OT::GlyphID ligature_list[ARRAY_LENGTH_CONST (first_glyphs) * ARRAY_LENGTH_CONST(ligature_table[0].ligatures)];

   unsigned int component_count_list[ARRAY_LENGTH_CONST (ligature_list)];

   OT::GlyphID component_list[ARRAY_LENGTH_CONST (ligature_list) * 1/* One extra component per ligature */];

   unsigned int num_ligatures = 0;

   /* Populate arrays */

   /* Sort out the first-glyphs */

   for (unsigned int first_glyph_idx = 0; first_glyph_idx < ARRAY_LENGTH (first_glyphs); first_glyph_idx++)

   {

     hb_codepoint_t first_u = ligature_table[first_glyph_idx].first;

     hb_codepoint_t first_glyph;

     if (!hb_font_get_glyph (font, first_u, 0, &first_glyph))

       continue;

     first_glyphs[num_first_glyphs].set (first_glyph);

     ligature_per_first_glyph_count_list[num_first_glyphs] = 0;

     first_glyphs_indirection[num_first_glyphs] = first_glyph_idx;

     num_first_glyphs++;

   }

   hb_bubble_sort (&first_glyphs[0], num_first_glyphs, OT::GlyphID::cmp, &first_glyphs_indirection[0]);

   /* Now that the first-glyphs are sorted, walk again, populate ligatures. */

   for (unsigned int i = 0; i < num_first_glyphs; i++)

   {

     unsigned int first_glyph_idx = first_glyphs_indirection[i];

     for (unsigned int second_glyph_idx = 0; second_glyph_idx < ARRAY_LENGTH (ligature_table[0].ligatures); second_glyph_idx++)

     {

       hb_codepoint_t second_u   = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].second;

       hb_codepoint_t ligature_u = ligature_table[first_glyph_idx].ligatures[second_glyph_idx].ligature;

       hb_codepoint_t second_glyph, ligature_glyph;

       if (!second_u ||

 	  !hb_font_get_glyph (font, second_u,   0, &second_glyph) ||

 	  !hb_font_get_glyph (font, ligature_u, 0, &ligature_glyph))

 	continue;

       ligature_per_first_glyph_count_list[i]++;

       ligature_list[num_ligatures].set (ligature_glyph);

       component_count_list[num_ligatures] = 2;

       component_list[num_ligatures].set (second_glyph);

       num_ligatures++;

     }

   }

   OT::Supplier<OT::GlyphID>   first_glyphs_supplier                      (first_glyphs, num_first_glyphs);

   OT::Supplier<unsigned int > ligature_per_first_glyph_count_supplier    (ligature_per_first_glyph_count_list, num_first_glyphs);

   OT::Supplier<OT::GlyphID>   ligatures_supplier                         (ligature_list, num_ligatures);

   OT::Supplier<unsigned int > component_count_supplier                   (component_count_list, num_ligatures);

   OT::Supplier<OT::GlyphID>   component_supplier                         (component_list, num_ligatures);

   /* 16 bytes per ligature ought to be enough... */

   char buf[ARRAY_LENGTH_CONST (ligature_list) * 16 + 128];

   OT::hb_serialize_context_t c (buf, sizeof (buf));

   OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> ();

   bool ret = lookup->serialize_ligature (&c,

 					 OT::LookupFlag::IgnoreMarks,

 					 first_glyphs_supplier,

 					 ligature_per_first_glyph_count_supplier,

 					 num_first_glyphs,

 					 ligatures_supplier,

 					 component_count_supplier,

 					 component_supplier);

   c.end_serialize ();

   /* TODO sanitize the results? */

   return ret ? c.copy<OT::SubstLookup> () : NULL;

 }

 static OT::SubstLookup *

 arabic_fallback_synthesize_lookup (const hb_ot_shape_plan_t *plan,

 				   hb_font_t *font,

 				   unsigned int feature_index)

 {

   if (feature_index < 4)

     return arabic_fallback_synthesize_lookup_single (plan, font, feature_index);

   else

     return arabic_fallback_synthesize_lookup_ligature (plan, font);

 }

 struct arabic_fallback_plan_t

 {

   ASSERT_POD ();

   hb_mask_t mask_array[ARABIC_NUM_FALLBACK_FEATURES];

   OT::SubstLookup *lookup_array[ARABIC_NUM_FALLBACK_FEATURES];

   hb_ot_layout_lookup_accelerator_t accel_array[ARABIC_NUM_FALLBACK_FEATURES];

 };

 static const arabic_fallback_plan_t arabic_fallback_plan_nil = {};

 static arabic_fallback_plan_t *

 arabic_fallback_plan_create (const hb_ot_shape_plan_t *plan,

 			     hb_font_t *font)

 {

   arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) calloc (1, sizeof (arabic_fallback_plan_t));

   if (unlikely (!fallback_plan))

     return const_cast<arabic_fallback_plan_t *> (&arabic_fallback_plan_nil);

   for (unsigned int i = 0; i < ARABIC_NUM_FALLBACK_FEATURES; i++)

   {

     fallback_plan->mask_array[i] = plan->map.get_1_mask (arabic_fallback_features[i]);

     if (fallback_plan->mask_array[i]) {

       fallback_plan->lookup_array[i] = arabic_fallback_synthesize_lookup (plan, font, i);

       if (fallback_plan->lookup_array[i])

 	fallback_plan->accel_array[i].init (*fallback_plan->lookup_array[i]);

     }

   }

   return fallback_plan;

 }

 static void

 arabic_fallback_plan_destroy (arabic_fallback_plan_t *fallback_plan)

 {

   if (!fallback_plan || fallback_plan == &arabic_fallback_plan_nil)

     return;

   for (unsigned int i = 0; i < ARABIC_NUM_FALLBACK_FEATURES; i++)

     if (fallback_plan->lookup_array[i])

     {

       fallback_plan->accel_array[i].fini (fallback_plan->lookup_array[i]);

       free (fallback_plan->lookup_array[i]);

     }

   free (fallback_plan);

 }

 static void

 arabic_fallback_plan_shape (arabic_fallback_plan_t *fallback_plan,

 			    hb_font_t *font,

 			    hb_buffer_t *buffer)

 {

   OT::hb_apply_context_t c (0, font, buffer);

   for (unsigned int i = 0; i < ARABIC_NUM_FALLBACK_FEATURES; i++)

     if (fallback_plan->lookup_array[i]) {

       c.set_lookup_mask (fallback_plan->mask_array[i]);

       hb_ot_layout_substitute_lookup (&c,

 				      *fallback_plan->lookup_array[i],

 				      fallback_plan->accel_array[i]);

     }

 }

 #endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */