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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_SHAPER_ARABIC_FALLBACK_HH
#define HB_OT_SHAPER_ARABIC_FALLBACK_HH
#include "hb.hh"
#include "hb-ot-shape.hh"
#include "hb-ot-layout-gsub-table.hh"
/* Features ordered the same as the entries in shaping_table rows,
* followed by rlig. Don't change.
*
* We currently support one subtable per lookup, and one lookup
* per feature. But we allow duplicate features, so we use that!
*/
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'),
HB_TAG('r','l','i','g'),
HB_TAG('r','l','i','g'),
};
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::HBGlyphID16 glyphs[SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1];
OT::HBGlyphID16 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 > 0xFFFFu || s_glyph > 0xFFFFu)
continue;
glyphs[num_glyphs] = u_glyph;
substitutes[num_glyphs] = s_glyph;
num_glyphs++;
}
if (!num_glyphs)
return nullptr;
/* Bubble-sort or something equally good!
* May not be good-enough for presidential candidate interviews, but good-enough for us... */
hb_stable_sort (&glyphs[0], num_glyphs,
(int(*)(const OT::HBUINT16*, const OT::HBUINT16 *)) OT::HBGlyphID16::cmp,
&substitutes[0]);
/* Each glyph takes four bytes max, and there's some overhead. */
char buf[(SHAPING_TABLE_LAST - SHAPING_TABLE_FIRST + 1) * 4 + 128];
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,
hb_sorted_array (glyphs, num_glyphs),
hb_array (substitutes, num_glyphs));
c.end_serialize ();
return ret && !c.in_error () ? c.copy<OT::SubstLookup> () : nullptr;
}
template <typename T>
static OT::SubstLookup *
arabic_fallback_synthesize_lookup_ligature (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_font_t *font,
const T &ligature_table,
unsigned lookup_flags)
{
OT::HBGlyphID16 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 have the same number of components. */
OT::HBGlyphID16 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::HBGlyphID16 component_list[ARRAY_LENGTH_CONST (ligature_list) *
ARRAY_LENGTH_CONST (ligature_table[0].ligatures[0].components)];
unsigned int num_ligatures = 0;
unsigned int num_components = 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] = 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_stable_sort (&first_glyphs[0], num_first_glyphs,
(int(*)(const OT::HBUINT16*, const OT::HBUINT16 *)) OT::HBGlyphID16::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 ligature_idx = 0; ligature_idx < ARRAY_LENGTH (ligature_table[0].ligatures); ligature_idx++)
{
hb_codepoint_t ligature_u = ligature_table[first_glyph_idx].ligatures[ligature_idx].ligature;
hb_codepoint_t ligature_glyph;
if (!hb_font_get_glyph (font, ligature_u, 0, &ligature_glyph))
continue;
const auto &components = ligature_table[first_glyph_idx].ligatures[ligature_idx].components;
unsigned component_count = ARRAY_LENGTH_CONST (components);
bool matched = true;
for (unsigned j = 0; j < component_count; j++)
{
hb_codepoint_t component_u = ligature_table[first_glyph_idx].ligatures[ligature_idx].components[j];
hb_codepoint_t component_glyph;
if (!component_u ||
!hb_font_get_nominal_glyph (font, component_u, &component_glyph))
{
matched = false;
break;
}
component_list[num_components++] = component_glyph;
}
if (!matched)
continue;
component_count_list[num_ligatures] = 1 + component_count;
ligature_list[num_ligatures] = ligature_glyph;
ligature_per_first_glyph_count_list[i]++;
num_ligatures++;
}
}
if (!num_ligatures)
return nullptr;
/* 16 bytes per ligature ought to be enough... */
char buf[ARRAY_LENGTH_CONST (ligature_list) * 16 + 128];
hb_serialize_context_t c (buf, sizeof (buf));
OT::SubstLookup *lookup = c.start_serialize<OT::SubstLookup> ();
bool ret = lookup->serialize_ligature (&c,
lookup_flags,
hb_sorted_array (first_glyphs, num_first_glyphs),
hb_array (ligature_per_first_glyph_count_list, num_first_glyphs),
hb_array (ligature_list, num_ligatures),
hb_array (component_count_list, num_ligatures),
hb_array (component_list, num_components));
c.end_serialize ();
return ret && !c.in_error () ? c.copy<OT::SubstLookup> () : nullptr;
}
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
{
switch (feature_index) {
case 4: return arabic_fallback_synthesize_lookup_ligature (plan, font, ligature_3_table, OT::LookupFlag::IgnoreMarks);
case 5: return arabic_fallback_synthesize_lookup_ligature (plan, font, ligature_table, OT::LookupFlag::IgnoreMarks);
case 6: return arabic_fallback_synthesize_lookup_ligature (plan, font, ligature_mark_table, 0);
}
}
assert (false);
return nullptr;
}
#define ARABIC_FALLBACK_MAX_LOOKUPS ARRAY_LENGTH_CONST (arabic_fallback_features)
struct arabic_fallback_plan_t
{
unsigned int num_lookups;
bool free_lookups;
hb_mask_t mask_array[ARABIC_FALLBACK_MAX_LOOKUPS];
OT::SubstLookup *lookup_array[ARABIC_FALLBACK_MAX_LOOKUPS];
OT::hb_ot_layout_lookup_accelerator_t *accel_array[ARABIC_FALLBACK_MAX_LOOKUPS];
};
#if defined(_WIN32) && !defined(HB_NO_WIN1256)
#define HB_WITH_WIN1256
#endif
#ifdef HB_WITH_WIN1256
#include "hb-ot-shaper-arabic-win1256.hh"
#endif
struct ManifestLookup
{
public:
OT::Tag tag;
OT::Offset16To<OT::SubstLookup> lookupOffset;
public:
DEFINE_SIZE_STATIC (6);
};
typedef OT::Array16Of<ManifestLookup> Manifest;
static bool
arabic_fallback_plan_init_win1256 (arabic_fallback_plan_t *fallback_plan HB_UNUSED,
const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_font_t *font HB_UNUSED)
{
#ifdef HB_WITH_WIN1256
/* Does this font look like it's Windows-1256-encoded? */
hb_codepoint_t g;
if (!(hb_font_get_glyph (font, 0x0627u, 0, &g) && g == 199 /* ALEF */ &&
hb_font_get_glyph (font, 0x0644u, 0, &g) && g == 225 /* LAM */ &&
hb_font_get_glyph (font, 0x0649u, 0, &g) && g == 236 /* ALEF MAKSURA */ &&
hb_font_get_glyph (font, 0x064Au, 0, &g) && g == 237 /* YEH */ &&
hb_font_get_glyph (font, 0x0652u, 0, &g) && g == 250 /* SUKUN */))
return false;
const Manifest &manifest = reinterpret_cast<const Manifest&> (arabic_win1256_gsub_lookups.manifest);
static_assert (sizeof (arabic_win1256_gsub_lookups.manifestData) <=
ARABIC_FALLBACK_MAX_LOOKUPS * sizeof (ManifestLookup), "");
unsigned j = 0;
unsigned int count = manifest.len;
for (unsigned int i = 0; i < count; i++)
{
fallback_plan->mask_array[j] = plan->map.get_1_mask (manifest[i].tag);
if (fallback_plan->mask_array[j])
{
fallback_plan->lookup_array[j] = const_cast<OT::SubstLookup*> (&(&manifest+manifest[i].lookupOffset));
if (fallback_plan->lookup_array[j])
{
fallback_plan->accel_array[j] = OT::hb_ot_layout_lookup_accelerator_t::create (*fallback_plan->lookup_array[j]);
j++;
}
}
}
fallback_plan->num_lookups = j;
fallback_plan->free_lookups = false;
return j > 0;
#else
return false;
#endif
}
static bool
arabic_fallback_plan_init_unicode (arabic_fallback_plan_t *fallback_plan,
const hb_ot_shape_plan_t *plan,
hb_font_t *font)
{
static_assert ((ARRAY_LENGTH_CONST (arabic_fallback_features) <= ARABIC_FALLBACK_MAX_LOOKUPS), "");
unsigned int j = 0;
for (unsigned int i = 0; i < ARRAY_LENGTH(arabic_fallback_features) ; i++)
{
fallback_plan->mask_array[j] = plan->map.get_1_mask (arabic_fallback_features[i]);
if (fallback_plan->mask_array[j])
{
fallback_plan->lookup_array[j] = arabic_fallback_synthesize_lookup (plan, font, i);
if (fallback_plan->lookup_array[j])
{
fallback_plan->accel_array[j] = OT::hb_ot_layout_lookup_accelerator_t::create (*fallback_plan->lookup_array[j]);
j++;
}
}
}
fallback_plan->num_lookups = j;
fallback_plan->free_lookups = true;
return j > 0;
}
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 *) hb_calloc (1, sizeof (arabic_fallback_plan_t));
if (unlikely (!fallback_plan))
return const_cast<arabic_fallback_plan_t *> (&Null (arabic_fallback_plan_t));
fallback_plan->num_lookups = 0;
fallback_plan->free_lookups = false;
/* Try synthesizing GSUB table using Unicode Arabic Presentation Forms,
* in case the font has cmap entries for the presentation-forms characters. */
if (arabic_fallback_plan_init_unicode (fallback_plan, plan, font))
return fallback_plan;
/* See if this looks like a Windows-1256-encoded font. If it does, use a
* hand-coded GSUB table. */
if (arabic_fallback_plan_init_win1256 (fallback_plan, plan, font))
return fallback_plan;
assert (fallback_plan->num_lookups == 0);
hb_free (fallback_plan);
return const_cast<arabic_fallback_plan_t *> (&Null (arabic_fallback_plan_t));
}
static void
arabic_fallback_plan_destroy (arabic_fallback_plan_t *fallback_plan)
{
if (!fallback_plan || fallback_plan->num_lookups == 0)
return;
for (unsigned int i = 0; i < fallback_plan->num_lookups; i++)
if (fallback_plan->lookup_array[i])
{
hb_free (fallback_plan->accel_array[i]);
if (fallback_plan->free_lookups)
hb_free (fallback_plan->lookup_array[i]);
}
hb_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_ot_apply_context_t c (0, font, buffer);
for (unsigned int i = 0; i < fallback_plan->num_lookups; i++)
if (fallback_plan->lookup_array[i]) {
c.set_lookup_mask (fallback_plan->mask_array[i]);
if (fallback_plan->accel_array[i])
hb_ot_layout_substitute_lookup (&c,
*fallback_plan->lookup_array[i],
*fallback_plan->accel_array[i]);
}
}
#endif /* HB_OT_SHAPER_ARABIC_FALLBACK_HH */
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