harfbuzz/src/hb-ot-shape-complex-arabic.cc

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/*
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* Copyright © 2010 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
*/
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#include "hb-ot-shape-complex-private.hh"
/* buffer var allocations */
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#define arabic_shaping_action() complex_var_temporary_u16() /* arabic shaping action */
/*
* Bits used in the joining tables
*/
enum {
JOINING_TYPE_U = 0,
JOINING_TYPE_R = 1,
JOINING_TYPE_D = 2,
JOINING_TYPE_C = JOINING_TYPE_D,
JOINING_GROUP_ALAPH = 3,
JOINING_GROUP_DALATH_RISH = 4,
NUM_STATE_MACHINE_COLS = 5,
/* We deliberately don't have a JOINING_TYPE_L since that's unused in Unicode. */
JOINING_TYPE_T = 6,
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JOINING_TYPE_X = 7 /* means: use general-category to choose between U or T. */
};
/*
* Joining types:
*/
#include "hb-ot-shape-complex-arabic-table.hh"
static unsigned int get_joining_type (hb_codepoint_t u, hb_unicode_general_category_t gen_cat)
{
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if (likely (hb_in_range<hb_codepoint_t> (u, JOINING_TABLE_FIRST, JOINING_TABLE_LAST))) {
unsigned int j_type = joining_table[u - JOINING_TABLE_FIRST];
if (likely (j_type != JOINING_TYPE_X))
return j_type;
}
/* Mongolian joining data is not in ArabicJoining.txt yet */
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if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x1800, 0x18AF)))
{
/* All letters, SIBE SYLLABLE BOUNDARY MARKER, and NIRUGU are D */
if (gen_cat == HB_UNICODE_GENERAL_CATEGORY_OTHER_LETTER || u == 0x1807 || u == 0x180A)
return JOINING_TYPE_D;
}
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if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x200C, 0x200D))) {
return u == 0x200C ? JOINING_TYPE_U : JOINING_TYPE_C;
}
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return (FLAG(gen_cat) & (FLAG(HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK) | FLAG(HB_UNICODE_GENERAL_CATEGORY_ENCLOSING_MARK) | FLAG(HB_UNICODE_GENERAL_CATEGORY_FORMAT))) ?
JOINING_TYPE_T : JOINING_TYPE_U;
}
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static hb_codepoint_t get_arabic_shape (hb_codepoint_t u, unsigned int shape)
{
if (likely (hb_in_range<hb_codepoint_t> (u, SHAPING_TABLE_FIRST, SHAPING_TABLE_LAST)) && shape < 4)
return shaping_table[u - SHAPING_TABLE_FIRST][shape];
return u;
}
static uint16_t get_ligature (hb_codepoint_t first, hb_codepoint_t second)
{
if (unlikely (!second)) return 0;
for (unsigned i = 0; i < ARRAY_LENGTH (ligature_table); i++)
if (ligature_table[i].first == first)
for (unsigned j = 0; j < ARRAY_LENGTH (ligature_table[i].ligatures); j++)
if (ligature_table[i].ligatures[j].second == second)
return ligature_table[i].ligatures[j].ligature;
return 0;
}
static const hb_tag_t arabic_syriac_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'),
/* Syriac */
HB_TAG('m','e','d','2'),
HB_TAG('f','i','n','2'),
HB_TAG('f','i','n','3'),
HB_TAG_NONE
};
/* Same order as the feature array */
enum {
INIT,
MEDI,
FINA,
ISOL,
/* Syriac */
MED2,
FIN2,
FIN3,
NONE,
COMMON_NUM_FEATURES = 4,
SYRIAC_NUM_FEATURES = 7,
TOTAL_NUM_FEATURES = NONE
};
static const struct arabic_state_table_entry {
uint8_t prev_action;
uint8_t curr_action;
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uint16_t next_state;
} arabic_state_table[][NUM_STATE_MACHINE_COLS] =
{
/* jt_U, jt_R, jt_D, jg_ALAPH, jg_DALATH_RISH */
/* State 0: prev was U, not willing to join. */
{ {NONE,NONE,0}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,ISOL,1}, {NONE,ISOL,6}, },
/* State 1: prev was R or ISOL/ALAPH, not willing to join. */
{ {NONE,NONE,0}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN2,5}, {NONE,ISOL,6}, },
/* State 2: prev was D/ISOL, willing to join. */
{ {NONE,NONE,0}, {INIT,FINA,1}, {INIT,FINA,3}, {INIT,FINA,4}, {INIT,FINA,6}, },
/* State 3: prev was D/FINA, willing to join. */
{ {NONE,NONE,0}, {MEDI,FINA,1}, {MEDI,FINA,3}, {MEDI,FINA,4}, {MEDI,FINA,6}, },
/* State 4: prev was FINA ALAPH, not willing to join. */
{ {NONE,NONE,0}, {MED2,ISOL,1}, {MED2,ISOL,2}, {MED2,FIN2,5}, {MED2,ISOL,6}, },
/* State 5: prev was FIN2/FIN3 ALAPH, not willing to join. */
{ {NONE,NONE,0}, {ISOL,ISOL,1}, {ISOL,ISOL,2}, {ISOL,FIN2,5}, {ISOL,ISOL,6}, },
/* State 6: prev was DALATH/RISH, not willing to join. */
{ {NONE,NONE,0}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN3,5}, {NONE,ISOL,6}, }
};
void
_hb_ot_shape_complex_collect_features_arabic (hb_ot_map_builder_t *map, const hb_segment_properties_t *props)
{
/* For Language forms (in ArabicOT speak), we do the iso/fina/medi/init together,
* then rlig and calt each in their own stage. This makes IranNastaliq's ALLAH
* ligature work correctly. It's unfortunate though...
*
* This also makes Arial Bold in Windows7 work. See:
* https://bugzilla.mozilla.org/show_bug.cgi?id=644184
*
* TODO: Add test cases for these two.
*/
map->add_bool_feature (HB_TAG('c','c','m','p'));
map->add_bool_feature (HB_TAG('l','o','c','l'));
map->add_gsub_pause (NULL, NULL);
unsigned int num_features = props->script == HB_SCRIPT_SYRIAC ? SYRIAC_NUM_FEATURES : COMMON_NUM_FEATURES;
for (unsigned int i = 0; i < num_features; i++)
map->add_bool_feature (arabic_syriac_features[i], false);
map->add_gsub_pause (NULL, NULL);
map->add_bool_feature (HB_TAG('r','l','i','g'));
map->add_gsub_pause (NULL, NULL);
map->add_bool_feature (HB_TAG('c','a','l','t'));
map->add_gsub_pause (NULL, NULL);
/* ArabicOT spec enables 'cswh' for Arabic where as for basic shaper it's disabled by default. */
map->add_bool_feature (HB_TAG('c','s','w','h'));
}
hb_ot_shape_normalization_mode_t
_hb_ot_shape_complex_normalization_preference_arabic (void)
{
return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS;
}
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static void
arabic_fallback_shape (hb_font_t *font, hb_buffer_t *buffer)
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{
unsigned int count = buffer->len;
hb_codepoint_t glyph;
/* Shape to presentation forms */
for (unsigned int i = 0; i < count; i++) {
hb_codepoint_t u = buffer->info[i].codepoint;
hb_codepoint_t shaped = get_arabic_shape (u, buffer->info[i].arabic_shaping_action());
if (shaped != u && hb_font_get_glyph (font, shaped, 0, &glyph))
buffer->info[i].codepoint = shaped;
}
/* Mandatory ligatures */
buffer->clear_output ();
for (buffer->idx = 0; buffer->idx + 1 < count;) {
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hb_codepoint_t ligature = get_ligature (buffer->info[buffer->idx].codepoint,
buffer->info[buffer->idx + 1].codepoint);
if (likely (!ligature) || !(hb_font_get_glyph (font, ligature, 0, &glyph))) {
buffer->next_glyph ();
continue;
}
buffer->replace_glyphs (2, 1, &ligature);
/* Technically speaking we can skip marks and stuff, like the GSUB path does.
* But who cares, we're in fallback! */
}
for (; buffer->idx < count;)
buffer->next_glyph ();
buffer->swap_buffers ();
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}
void
_hb_ot_shape_complex_setup_masks_arabic (hb_ot_map_t *map, hb_buffer_t *buffer, hb_font_t *font)
{
unsigned int count = buffer->len;
unsigned int prev = 0, state = 0;
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HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
for (unsigned int i = 0; i < count; i++)
{
unsigned int this_type = get_joining_type (buffer->info[i].codepoint, (hb_unicode_general_category_t) buffer->info[i].general_category());
if (unlikely (this_type == JOINING_TYPE_T)) {
buffer->info[i].arabic_shaping_action() = NONE;
continue;
}
const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
if (entry->prev_action != NONE)
buffer->info[prev].arabic_shaping_action() = entry->prev_action;
buffer->info[i].arabic_shaping_action() = entry->curr_action;
prev = i;
state = entry->next_state;
}
hb_mask_t mask_array[TOTAL_NUM_FEATURES + 1] = {0};
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hb_mask_t total_masks = 0;
unsigned int num_masks = buffer->props.script == HB_SCRIPT_SYRIAC ? SYRIAC_NUM_FEATURES : COMMON_NUM_FEATURES;
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for (unsigned int i = 0; i < num_masks; i++) {
mask_array[i] = map->get_1_mask (arabic_syriac_features[i]);
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total_masks |= mask_array[i];
}
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if (total_masks) {
/* Has OpenType tables */
for (unsigned int i = 0; i < count; i++)
buffer->info[i].mask |= mask_array[buffer->info[i].arabic_shaping_action()];
} else if (buffer->props.script == HB_SCRIPT_ARABIC) {
/* Fallback Arabic shaping to Presentation Forms */
/* Pitfalls:
* - This path fires if user force-set init/medi/fina/isol off,
* - If font does not declare script 'arab', well, what to do?
* Most probably it's safe to assume that init/medi/fina/isol
* still mean Arabic shaping, although they do not have to.
*/
arabic_fallback_shape (font, buffer);
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}
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HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
}