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

383 lines
12 KiB
C++

/*
* Copyright © 2010,2012 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-ot-shape-complex-private.hh"
#include "hb-ot-shape-private.hh"
/* buffer var allocations */
#define arabic_shaping_action() complex_var_u8_0() /* arabic shaping action */
/*
* Bits used in the joining tables
*/
enum {
JOINING_TYPE_U = 0,
JOINING_TYPE_L = 1,
JOINING_TYPE_R = 2,
JOINING_TYPE_D = 3,
JOINING_TYPE_C = JOINING_TYPE_D,
JOINING_GROUP_ALAPH = 4,
JOINING_GROUP_DALATH_RISH = 5,
NUM_STATE_MACHINE_COLS = 6,
JOINING_TYPE_T = 7,
JOINING_TYPE_X = 8 /* 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)
{
unsigned int j_type = joining_type(u);
if (likely (j_type != JOINING_TYPE_X))
return j_type;
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;
}
#define FEATURE_IS_SYRIAC(tag) hb_in_range<unsigned char> ((unsigned char) (tag), '2', '3')
static const hb_tag_t arabic_features[] =
{
HB_TAG('i','s','o','l'),
HB_TAG('f','i','n','a'),
HB_TAG('f','i','n','2'),
HB_TAG('f','i','n','3'),
HB_TAG('m','e','d','i'),
HB_TAG('m','e','d','2'),
HB_TAG('i','n','i','t'),
HB_TAG_NONE
};
/* Same order as the feature array */
enum {
ISOL,
FINA,
FIN2,
FIN3,
MEDI,
MED2,
INIT,
NONE,
ARABIC_NUM_FEATURES = NONE
};
static const struct arabic_state_table_entry {
uint8_t prev_action;
uint8_t curr_action;
uint16_t next_state;
} arabic_state_table[][NUM_STATE_MACHINE_COLS] =
{
/* jt_U, jt_L, jt_R, jt_D, jg_ALAPH, jg_DALATH_RISH */
/* State 0: prev was U, not willing to join. */
{ {NONE,NONE,0}, {NONE,ISOL,2}, {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,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN2,5}, {NONE,ISOL,6}, },
/* State 2: prev was D/L in ISOL form, willing to join. */
{ {NONE,NONE,0}, {NONE,ISOL,2}, {INIT,FINA,1}, {INIT,FINA,3}, {INIT,FINA,4}, {INIT,FINA,6}, },
/* State 3: prev was D in FINA form, willing to join. */
{ {NONE,NONE,0}, {NONE,ISOL,2}, {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}, {NONE,ISOL,2}, {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}, {NONE,ISOL,2}, {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,2}, {NONE,ISOL,1}, {NONE,ISOL,2}, {NONE,FIN3,5}, {NONE,ISOL,6}, }
};
static void
nuke_joiners (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
arabic_fallback_shape (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
collect_features_arabic (hb_ot_shape_planner_t *plan)
{
hb_ot_map_builder_t *map = &plan->map;
/* We apply features according to the Arabic spec, with pauses
* in between most.
*
* The pause between init/medi/... and rlig is required. See eg:
* https://bugzilla.mozilla.org/show_bug.cgi?id=644184
*
* The pauses between init/medi/... themselves are not necessarily
* needed as only one of those features is applied to any character.
* The only difference it makes is when fonts have contextual
* substitutions. We now follow the order of the spec, which makes
* for better experience if that's what Uniscribe is doing.
*
* At least for Arabic, looks like Uniscribe has a pause between
* rlig and calt. Otherwise the IranNastaliq's ALLAH ligature won't
* work. However, testing shows that rlig and calt are applied
* together for Mongolian in Uniscribe. As such, we only add a
* pause for Arabic, not other scripts.
*/
map->add_gsub_pause (nuke_joiners);
map->add_global_bool_feature (HB_TAG('c','c','m','p'));
map->add_global_bool_feature (HB_TAG('l','o','c','l'));
map->add_gsub_pause (NULL);
for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++)
{
bool has_fallback = plan->props.script == HB_SCRIPT_ARABIC && !FEATURE_IS_SYRIAC (arabic_features[i]);
map->add_feature (arabic_features[i], 1, has_fallback ? F_HAS_FALLBACK : F_NONE);
map->add_gsub_pause (NULL);
}
map->add_feature (HB_TAG('r','l','i','g'), 1, F_GLOBAL|F_HAS_FALLBACK);
if (plan->props.script == HB_SCRIPT_ARABIC)
map->add_gsub_pause (arabic_fallback_shape);
map->add_global_bool_feature (HB_TAG('c','a','l','t'));
map->add_gsub_pause (NULL);
/* The spec includes 'cswh'. Earlier versions of Windows
* used to enable this by default, but testing suggests
* that Windows 8 and later do not enable it by default,
* and spec now says 'Off by default'.
* We disabled this in ae23c24c32.
* Note that IranNastaliq uses this feature extensively
* to fixup broken glyph sequences. Oh well...
* Test case: U+0643,U+0640,U+0631. */
//map->add_global_bool_feature (HB_TAG('c','s','w','h'));
map->add_global_bool_feature (HB_TAG('m','s','e','t'));
}
#include "hb-ot-shape-complex-arabic-fallback.hh"
struct arabic_shape_plan_t
{
ASSERT_POD ();
/* The "+ 1" in the next array is to accommodate for the "NONE" command,
* which is not an OpenType feature, but this simplifies the code by not
* having to do a "if (... < NONE) ..." and just rely on the fact that
* mask_array[NONE] == 0. */
hb_mask_t mask_array[ARABIC_NUM_FEATURES + 1];
bool do_fallback;
arabic_fallback_plan_t *fallback_plan;
};
static void *
data_create_arabic (const hb_ot_shape_plan_t *plan)
{
arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) calloc (1, sizeof (arabic_shape_plan_t));
if (unlikely (!arabic_plan))
return NULL;
arabic_plan->do_fallback = plan->props.script == HB_SCRIPT_ARABIC;
for (unsigned int i = 0; i < ARABIC_NUM_FEATURES; i++) {
arabic_plan->mask_array[i] = plan->map.get_1_mask (arabic_features[i]);
arabic_plan->do_fallback = arabic_plan->do_fallback &&
(FEATURE_IS_SYRIAC (arabic_features[i]) ||
plan->map.needs_fallback (arabic_features[i]));
}
return arabic_plan;
}
static void
data_destroy_arabic (void *data)
{
arabic_shape_plan_t *arabic_plan = (arabic_shape_plan_t *) data;
arabic_fallback_plan_destroy (arabic_plan->fallback_plan);
free (data);
}
static void
arabic_joining (hb_buffer_t *buffer)
{
unsigned int count = buffer->len;
hb_glyph_info_t *info = buffer->info;
unsigned int prev = (unsigned int) -1, state = 0;
/* Check pre-context */
for (unsigned int i = 0; i < buffer->context_len[0]; i++)
{
unsigned int this_type = get_joining_type (buffer->context[0][i], buffer->unicode->general_category (buffer->context[0][i]));
if (unlikely (this_type == JOINING_TYPE_T))
continue;
const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
state = entry->next_state;
break;
}
for (unsigned int i = 0; i < count; i++)
{
unsigned int this_type = get_joining_type (info[i].codepoint, _hb_glyph_info_get_general_category (&info[i]));
if (unlikely (this_type == JOINING_TYPE_T)) {
info[i].arabic_shaping_action() = NONE;
continue;
}
const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
if (entry->prev_action != NONE && prev != (unsigned int) -1)
info[prev].arabic_shaping_action() = entry->prev_action;
info[i].arabic_shaping_action() = entry->curr_action;
prev = i;
state = entry->next_state;
}
for (unsigned int i = 0; i < buffer->context_len[1]; i++)
{
unsigned int this_type = get_joining_type (buffer->context[1][i], buffer->unicode->general_category (buffer->context[1][i]));
if (unlikely (this_type == JOINING_TYPE_T))
continue;
const arabic_state_table_entry *entry = &arabic_state_table[state][this_type];
if (entry->prev_action != NONE && prev != (unsigned int) -1)
info[prev].arabic_shaping_action() = entry->prev_action;
break;
}
}
static void
mongolian_variation_selectors (hb_buffer_t *buffer)
{
/* Copy arabic_shaping_action() from base to Mongolian variation selectors. */
unsigned int count = buffer->len;
hb_glyph_info_t *info = buffer->info;
for (unsigned int i = 1; i < count; i++)
if (unlikely (hb_in_range (info[i].codepoint, 0x180Bu, 0x180Du)))
info[i].arabic_shaping_action() = info[i - 1].arabic_shaping_action();
}
static void
setup_masks_arabic (const hb_ot_shape_plan_t *plan,
hb_buffer_t *buffer,
hb_font_t *font HB_UNUSED)
{
HB_BUFFER_ALLOCATE_VAR (buffer, arabic_shaping_action);
const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
arabic_joining (buffer);
if (plan->props.script == HB_SCRIPT_MONGOLIAN)
mongolian_variation_selectors (buffer);
unsigned int count = buffer->len;
hb_glyph_info_t *info = buffer->info;
for (unsigned int i = 0; i < count; i++)
info[i].mask |= arabic_plan->mask_array[info[i].arabic_shaping_action()];
HB_BUFFER_DEALLOCATE_VAR (buffer, arabic_shaping_action);
}
static void
nuke_joiners (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_font_t *font HB_UNUSED,
hb_buffer_t *buffer)
{
unsigned int count = buffer->len;
hb_glyph_info_t *info = buffer->info;
for (unsigned int i = 0; i < count; i++)
if (_hb_glyph_info_is_zwj (&info[i]))
_hb_glyph_info_flip_joiners (&info[i]);
}
static void
arabic_fallback_shape (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer)
{
const arabic_shape_plan_t *arabic_plan = (const arabic_shape_plan_t *) plan->data;
if (!arabic_plan->do_fallback)
return;
retry:
arabic_fallback_plan_t *fallback_plan = (arabic_fallback_plan_t *) hb_atomic_ptr_get (&arabic_plan->fallback_plan);
if (unlikely (!fallback_plan))
{
/* This sucks. We need a font to build the fallback plan... */
fallback_plan = arabic_fallback_plan_create (plan, font);
if (unlikely (!hb_atomic_ptr_cmpexch (&(const_cast<arabic_shape_plan_t *> (arabic_plan))->fallback_plan, NULL, fallback_plan))) {
arabic_fallback_plan_destroy (fallback_plan);
goto retry;
}
}
arabic_fallback_plan_shape (fallback_plan, font, buffer);
}
const hb_ot_complex_shaper_t _hb_ot_complex_shaper_arabic =
{
"arabic",
collect_features_arabic,
NULL, /* override_features */
data_create_arabic,
data_destroy_arabic,
NULL, /* preprocess_text_arabic */
HB_OT_SHAPE_NORMALIZATION_MODE_DEFAULT,
NULL, /* decompose */
NULL, /* compose */
setup_masks_arabic,
HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_GDEF_LATE,
true, /* fallback_position */
};