/*
* 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_set_digest_t digest_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->lookup_array[i]->add_coverage (&fallback_plan->digest_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])
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)
{
for (unsigned int i = 0; i < ARABIC_NUM_FALLBACK_FEATURES; i++)
if (fallback_plan->lookup_array[i]) {
OT::hb_apply_context_t c (0, font, buffer, fallback_plan->mask_array[i], true/*auto_zwj*/);
fallback_plan->lookup_array[i]->apply_string (&c, &fallback_plan->digest_array[i]);
}
}
#endif /* HB_OT_SHAPE_COMPLEX_ARABIC_FALLBACK_HH */