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

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/*
* Copyright © 2011,2012 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-indic-private.hh"
#include "hb-ot-layout-private.hh"
/* buffer var allocations */
#define indic_category() complex_var_u8_0() /* indic_category_t */
#define indic_position() complex_var_u8_1() /* indic_position_t */
/*
* Indic shaper.
*/
#define IN_HALF_BLOCK(u, Base) (((u) & ~0x7F) == (Base))
#define IS_DEVA(u) (IN_HALF_BLOCK (u, 0x0900))
#define IS_BENG(u) (IN_HALF_BLOCK (u, 0x0980))
#define IS_GURU(u) (IN_HALF_BLOCK (u, 0x0A00))
#define IS_GUJR(u) (IN_HALF_BLOCK (u, 0x0A80))
#define IS_ORYA(u) (IN_HALF_BLOCK (u, 0x0B00))
#define IS_TAML(u) (IN_HALF_BLOCK (u, 0x0B80))
#define IS_TELU(u) (IN_HALF_BLOCK (u, 0x0C00))
#define IS_KNDA(u) (IN_HALF_BLOCK (u, 0x0C80))
#define IS_MLYM(u) (IN_HALF_BLOCK (u, 0x0D00))
#define IS_SINH(u) (IN_HALF_BLOCK (u, 0x0D80))
#define IS_KHMR(u) (IN_HALF_BLOCK (u, 0x1780))
#define MATRA_POS_LEFT(u) POS_PRE_M
#define MATRA_POS_RIGHT(u) ( \
IS_DEVA(u) ? POS_AFTER_SUB : \
IS_BENG(u) ? POS_AFTER_POST : \
IS_GURU(u) ? POS_AFTER_POST : \
IS_GUJR(u) ? POS_AFTER_POST : \
IS_ORYA(u) ? POS_AFTER_POST : \
IS_TAML(u) ? POS_AFTER_POST : \
IS_TELU(u) ? (u <= 0x0C42 ? POS_BEFORE_SUB : POS_AFTER_SUB) : \
IS_KNDA(u) ? (u < 0x0CC3 || u > 0xCD6 ? POS_BEFORE_SUB : POS_AFTER_SUB) : \
IS_MLYM(u) ? POS_AFTER_POST : \
IS_SINH(u) ? POS_AFTER_SUB : \
IS_KHMR(u) ? POS_AFTER_POST : \
/*default*/ POS_AFTER_SUB \
)
#define MATRA_POS_TOP(u) ( /* BENG and MLYM don't have top matras. */ \
IS_DEVA(u) ? POS_AFTER_SUB : \
IS_GURU(u) ? POS_AFTER_POST : /* Deviate from spec */ \
IS_GUJR(u) ? POS_AFTER_SUB : \
IS_ORYA(u) ? POS_AFTER_MAIN : \
IS_TAML(u) ? POS_AFTER_SUB : \
IS_TELU(u) ? POS_BEFORE_SUB : \
IS_KNDA(u) ? POS_BEFORE_SUB : \
IS_SINH(u) ? POS_AFTER_SUB : \
IS_KHMR(u) ? POS_AFTER_POST : \
/*default*/ POS_AFTER_SUB \
)
#define MATRA_POS_BOTTOM(u) ( \
IS_DEVA(u) ? POS_AFTER_SUB : \
IS_BENG(u) ? POS_AFTER_SUB : \
IS_GURU(u) ? POS_AFTER_POST : \
IS_GUJR(u) ? POS_AFTER_POST : \
IS_ORYA(u) ? POS_AFTER_SUB : \
IS_TAML(u) ? POS_AFTER_POST : \
IS_TELU(u) ? POS_BEFORE_SUB : \
IS_KNDA(u) ? POS_BEFORE_SUB : \
IS_MLYM(u) ? POS_AFTER_POST : \
IS_SINH(u) ? POS_AFTER_SUB : \
IS_KHMR(u) ? POS_AFTER_POST : \
/*default*/ POS_AFTER_SUB \
)
static inline indic_position_t
matra_position (hb_codepoint_t u, indic_position_t side)
{
switch ((int) side)
{
case POS_PRE_C: return MATRA_POS_LEFT (u);
case POS_POST_C: return MATRA_POS_RIGHT (u);
case POS_ABOVE_C: return MATRA_POS_TOP (u);
case POS_BELOW_C: return MATRA_POS_BOTTOM (u);
};
return side;
}
/* XXX
* This is a hack for now. We should move this data into the main Indic table.
* Or completely remove it and just check in the tables.
*/
static const hb_codepoint_t ra_chars[] = {
0x0930, /* Devanagari */
0x09B0, /* Bengali */
0x09F0, /* Bengali */
0x0A30, /* Gurmukhi */ /* No Reph */
0x0AB0, /* Gujarati */
0x0B30, /* Oriya */
0x0BB0, /* Tamil */ /* No Reph */
0x0C30, /* Telugu */ /* Reph formed only with ZWJ */
0x0CB0, /* Kannada */
0x0D30, /* Malayalam */ /* No Reph, Logical Repha */
0x0DBB, /* Sinhala */ /* Reph formed only with ZWJ */
0x179A, /* Khmer */ /* No Reph, Visual Repha */
};
static inline indic_position_t
consonant_position (hb_codepoint_t u)
{
if ((u & ~0x007F) == 0x1780)
return POS_BELOW_C; /* In Khmer coeng model, post and below forms should not be reordered. */
return POS_BASE_C; /* Will recategorize later based on font lookups. */
}
static inline bool
is_ra (hb_codepoint_t u)
{
for (unsigned int i = 0; i < ARRAY_LENGTH (ra_chars); i++)
if (u == ra_chars[i])
return true;
return false;
}
static inline bool
is_one_of (const hb_glyph_info_t &info, unsigned int flags)
{
/* If it ligated, all bets are off. */
if (is_a_ligature (info)) return false;
return !!(FLAG (info.indic_category()) & flags);
}
#define JOINER_FLAGS (FLAG (OT_ZWJ) | FLAG (OT_ZWNJ))
static inline bool
is_joiner (const hb_glyph_info_t &info)
{
return is_one_of (info, JOINER_FLAGS);
}
/* Note:
*
* We treat Vowels and placeholders as if they were consonants. This is safe because Vowels
* cannot happen in a consonant syllable. The plus side however is, we can call the
* consonant syllable logic from the vowel syllable function and get it all right! */
#define CONSONANT_FLAGS (FLAG (OT_C) | FLAG (OT_CM) | FLAG (OT_Ra) | FLAG (OT_V) | FLAG (OT_NBSP) | FLAG (OT_DOTTEDCIRCLE))
static inline bool
is_consonant (const hb_glyph_info_t &info)
{
return is_one_of (info, CONSONANT_FLAGS);
}
#define HALANT_OR_COENG_FLAGS (FLAG (OT_H) | FLAG (OT_Coeng))
static inline bool
is_halant_or_coeng (const hb_glyph_info_t &info)
{
return is_one_of (info, HALANT_OR_COENG_FLAGS);
}
static inline void
set_indic_properties (hb_glyph_info_t &info)
{
hb_codepoint_t u = info.codepoint;
unsigned int type = hb_indic_get_categories (u);
indic_category_t cat = (indic_category_t) (type & 0x7F);
indic_position_t pos = (indic_position_t) (type >> 8);
/*
* Re-assign category
*/
/* The spec says U+0952 is OT_A. However, testing shows that Uniscribe
* treats U+0951..U+0954 all behave similarly.
* TESTS:
* U+092E,U+0947,U+0952
* U+092E,U+0952,U+0947
* U+092E,U+0947,U+0951
* U+092E,U+0951,U+0947
*/
if (unlikely (hb_in_range<hb_codepoint_t> (u, 0x0951, 0x0954)))
cat = OT_A;
if (unlikely (u == 0x17D1))
cat = OT_X;
if (cat == OT_X &&
unlikely (hb_in_range<hb_codepoint_t> (u, 0x17CB, 0x17D3))) /* Khmer Various signs */
{
/* These are like Top Matras. */
cat = OT_M;
pos = POS_ABOVE_C;
}
if (u == 0x17C6) /* Khmer Bindu doesn't like to be repositioned. */
cat = OT_N;
if (unlikely (u == 0x17D2)) cat = OT_Coeng; /* Khmer coeng */
else if (unlikely (u == 0x200C)) cat = OT_ZWNJ;
else if (unlikely (u == 0x200D)) cat = OT_ZWJ;
else if (unlikely (u == 0x25CC)) cat = OT_DOTTEDCIRCLE;
else if (unlikely (u == 0x0A71)) cat = OT_SM; /* GURMUKHI ADDAK. Move it to the end. */
if (cat == OT_Repha) {
/* There are two kinds of characters marked as Repha:
* - The ones that are GenCat=Mn are already positioned visually, ie. after base. (eg. Khmer)
* - The ones that are GenCat=Lo is encoded logically, ie. beginning of syllable. (eg. Malayalam)
*
* We recategorize the first kind to look like a Nukta and attached to the base directly.
*/
if (_hb_glyph_info_get_general_category (&info) == HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK)
cat = OT_N;
}
/*
* Re-assign position.
*/
if ((FLAG (cat) & CONSONANT_FLAGS))
{
pos = consonant_position (u);
if (is_ra (u))
cat = OT_Ra;
}
else if (cat == OT_M)
{
pos = matra_position (u, pos);
}
else if ((FLAG (cat) & (FLAG (OT_SM) | FLAG (OT_VD) | FLAG (OT_A) | FLAG (OT_Avag))))
{
pos = POS_SMVD;
}
if (unlikely (u == 0x0B01)) pos = POS_BEFORE_SUB; /* Oriya Bindu is BeforeSub in the spec. */
info.indic_category() = cat;
info.indic_position() = pos;
}
/*
* Things above this line should ideally be moved to the Indic table itself.
*/
/*
* Indic configurations. Note that we do not want to keep every single script-specific
* behavior in these tables necessarily. This should mainly be used for per-script
* properties that are cheaper keeping here, than in the code. Ie. if, say, one and
* only one script has an exception, that one script can be if'ed directly in the code,
* instead of adding a new flag in these structs.
*/
enum base_position_t {
BASE_POS_FIRST,
BASE_POS_LAST
};
enum reph_position_t {
REPH_POS_DEFAULT = POS_BEFORE_POST,
REPH_POS_AFTER_MAIN = POS_AFTER_MAIN,
REPH_POS_BEFORE_SUB = POS_BEFORE_SUB,
REPH_POS_AFTER_SUB = POS_AFTER_SUB,
REPH_POS_BEFORE_POST = POS_BEFORE_POST,
REPH_POS_AFTER_POST = POS_AFTER_POST
};
enum reph_mode_t {
REPH_MODE_IMPLICIT, /* Reph formed out of initial Ra,H sequence. */
REPH_MODE_EXPLICIT, /* Reph formed out of initial Ra,H,ZWJ sequence. */
REPH_MODE_VIS_REPHA, /* Encoded Repha character, no reordering needed. */
REPH_MODE_LOG_REPHA /* Encoded Repha character, needs reordering. */
};
enum blwf_mode_t {
BLWF_MODE_PRE_AND_POST, /* Below-forms feature applied to pre-base and post-base. */
BLWF_MODE_POST_ONLY /* Below-forms feature applied to post-base only. */
};
struct indic_config_t
{
hb_script_t script;
bool has_old_spec;
hb_codepoint_t virama;
base_position_t base_pos;
reph_position_t reph_pos;
reph_mode_t reph_mode;
blwf_mode_t blwf_mode;
};
static const indic_config_t indic_configs[] =
{
/* Default. Should be first. */
{HB_SCRIPT_INVALID, false, 0,BASE_POS_LAST, REPH_POS_DEFAULT, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_DEVANAGARI,true, 0x094D,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_BENGALI, true, 0x09CD,BASE_POS_LAST, REPH_POS_AFTER_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_GURMUKHI, true, 0x0A4D,BASE_POS_LAST, REPH_POS_BEFORE_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_GUJARATI, true, 0x0ACD,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_ORIYA, true, 0x0B4D,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_TAMIL, true, 0x0BCD,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_TELUGU, true, 0x0C4D,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_POST_ONLY},
{HB_SCRIPT_KANNADA, true, 0x0CCD,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_POST_ONLY},
{HB_SCRIPT_MALAYALAM, true, 0x0D4D,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_LOG_REPHA,BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_SINHALA, false,0x0DCA,BASE_POS_FIRST,REPH_POS_AFTER_MAIN, REPH_MODE_EXPLICIT, BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_KHMER, false,0x17D2,BASE_POS_FIRST,REPH_POS_DEFAULT, REPH_MODE_VIS_REPHA,BLWF_MODE_PRE_AND_POST},
{HB_SCRIPT_JAVANESE, false,0xA9C0,BASE_POS_LAST, REPH_POS_DEFAULT, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
};
/*
* Indic shaper.
*/
struct feature_list_t {
hb_tag_t tag;
hb_ot_map_feature_flags_t flags;
};
static const feature_list_t
indic_features[] =
{
/*
* Basic features.
* These features are applied in order, one at a time, after initial_reordering.
*/
{HB_TAG('n','u','k','t'), F_GLOBAL},
{HB_TAG('a','k','h','n'), F_GLOBAL},
{HB_TAG('r','p','h','f'), F_NONE},
{HB_TAG('r','k','r','f'), F_GLOBAL},
{HB_TAG('p','r','e','f'), F_NONE},
{HB_TAG('b','l','w','f'), F_NONE},
{HB_TAG('a','b','v','f'), F_NONE},
{HB_TAG('h','a','l','f'), F_NONE},
{HB_TAG('p','s','t','f'), F_NONE},
{HB_TAG('v','a','t','u'), F_GLOBAL},
{HB_TAG('c','j','c','t'), F_GLOBAL},
{HB_TAG('c','f','a','r'), F_NONE},
/*
* Other features.
* These features are applied all at once, after final_reordering.
* Default Bengali font in Windows for example has intermixed
* lookups for init,pres,abvs,blws features.
*/
{HB_TAG('i','n','i','t'), F_NONE},
{HB_TAG('p','r','e','s'), F_GLOBAL},
{HB_TAG('a','b','v','s'), F_GLOBAL},
{HB_TAG('b','l','w','s'), F_GLOBAL},
{HB_TAG('p','s','t','s'), F_GLOBAL},
{HB_TAG('h','a','l','n'), F_GLOBAL},
/* Positioning features, though we don't care about the types. */
{HB_TAG('d','i','s','t'), F_GLOBAL},
{HB_TAG('a','b','v','m'), F_GLOBAL},
{HB_TAG('b','l','w','m'), F_GLOBAL},
};
/*
* Must be in the same order as the indic_features array.
*/
enum {
_NUKT,
_AKHN,
RPHF,
_RKRF,
PREF,
BLWF,
ABVF,
HALF,
PSTF,
_VATU,
_CJCT,
CFAR,
INIT,
_PRES,
_ABVS,
_BLWS,
_PSTS,
_HALN,
_DIST,
_ABVM,
_BLWM,
INDIC_NUM_FEATURES,
INDIC_BASIC_FEATURES = INIT /* Don't forget to update this! */
};
static void
setup_syllables (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
initial_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
final_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
clear_syllables (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer);
static void
collect_features_indic (hb_ot_shape_planner_t *plan)
{
hb_ot_map_builder_t *map = &plan->map;
/* Do this before any lookups have been applied. */
map->add_gsub_pause (setup_syllables);
map->add_global_bool_feature (HB_TAG('l','o','c','l'));
/* The Indic specs do not require ccmp, but we apply it here since if
* there is a use of it, it's typically at the beginning. */
map->add_global_bool_feature (HB_TAG('c','c','m','p'));
unsigned int i = 0;
map->add_gsub_pause (initial_reordering);
for (; i < INDIC_BASIC_FEATURES; i++) {
map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ);
map->add_gsub_pause (NULL);
}
map->add_gsub_pause (final_reordering);
for (; i < INDIC_NUM_FEATURES; i++) {
map->add_feature (indic_features[i].tag, 1, indic_features[i].flags | F_MANUAL_ZWJ);
}
map->add_global_bool_feature (HB_TAG('c','a','l','t'));
map->add_global_bool_feature (HB_TAG('c','l','i','g'));
map->add_gsub_pause (clear_syllables);
}
static void
override_features_indic (hb_ot_shape_planner_t *plan)
{
/* Uniscribe does not apply 'kern' in Khmer. */
if (hb_options ().uniscribe_bug_compatible)
{
switch ((hb_tag_t) plan->props.script)
{
case HB_SCRIPT_KHMER:
plan->map.add_feature (HB_TAG('k','e','r','n'), 0, F_GLOBAL);
break;
}
}
plan->map.add_feature (HB_TAG('l','i','g','a'), 0, F_GLOBAL);
}
struct would_substitute_feature_t
{
inline void init (const hb_ot_map_t *map, hb_tag_t feature_tag)
{
map->get_stage_lookups (0/*GSUB*/,
map->get_feature_stage (0/*GSUB*/, feature_tag),
&lookups, &count);
}
inline bool would_substitute (const hb_codepoint_t *glyphs,
unsigned int glyphs_count,
bool zero_context,
hb_face_t *face) const
{
for (unsigned int i = 0; i < count; i++)
if (hb_ot_layout_lookup_would_substitute_fast (face, lookups[i].index, glyphs, glyphs_count, zero_context))
return true;
return false;
}
private:
const hb_ot_map_t::lookup_map_t *lookups;
unsigned int count;
};
struct indic_shape_plan_t
{
ASSERT_POD ();
inline bool get_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const
{
hb_codepoint_t glyph = virama_glyph;
if (unlikely (virama_glyph == (hb_codepoint_t) -1))
{
if (!config->virama || !font->get_glyph (config->virama, 0, &glyph))
glyph = 0;
/* Technically speaking, the spec says we should apply 'locl' to virama too.
* Maybe one day... */
/* Our get_glyph() function needs a font, so we can't get the virama glyph
* during shape planning... Instead, overwrite it here. It's safe. Don't worry! */
(const_cast<indic_shape_plan_t *> (this))->virama_glyph = glyph;
}
*pglyph = glyph;
return glyph != 0;
}
const indic_config_t *config;
bool is_old_spec;
hb_codepoint_t virama_glyph;
would_substitute_feature_t rphf;
would_substitute_feature_t pref;
would_substitute_feature_t blwf;
would_substitute_feature_t pstf;
hb_mask_t mask_array[INDIC_NUM_FEATURES];
};
static void *
data_create_indic (const hb_ot_shape_plan_t *plan)
{
indic_shape_plan_t *indic_plan = (indic_shape_plan_t *) calloc (1, sizeof (indic_shape_plan_t));
if (unlikely (!indic_plan))
return NULL;
indic_plan->config = &indic_configs[0];
for (unsigned int i = 1; i < ARRAY_LENGTH (indic_configs); i++)
if (plan->props.script == indic_configs[i].script) {
indic_plan->config = &indic_configs[i];
break;
}
indic_plan->is_old_spec = indic_plan->config->has_old_spec && ((plan->map.chosen_script[0] & 0x000000FF) != '2');
indic_plan->virama_glyph = (hb_codepoint_t) -1;
indic_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f'));
indic_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'));
indic_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f'));
indic_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f'));
for (unsigned int i = 0; i < ARRAY_LENGTH (indic_plan->mask_array); i++)
indic_plan->mask_array[i] = (indic_features[i].flags & F_GLOBAL) ?
0 : plan->map.get_1_mask (indic_features[i].tag);
return indic_plan;
}
static void
data_destroy_indic (void *data)
{
free (data);
}
static indic_position_t
consonant_position_from_face (const indic_shape_plan_t *indic_plan,
const hb_codepoint_t glyphs[2],
hb_face_t *face)
{
/* For old-spec, the order of glyphs is Consonant,Virama,
* whereas for new-spec, it's Virama,Consonant. However,
* some broken fonts (like Free Sans) simply copied lookups
* from old-spec to new-spec without modification.
* And oddly enough, Uniscribe seems to respect those lookups.
* Eg. in the sequence U+0924,U+094D,U+0930, Uniscribe finds
* base at 0. The font however, only has lookups matching
* 930,94D in 'blwf', not the expected 94D,930 (with new-spec
* table). As such, we simply match both sequences. Seems
* to work. */
bool zero_context = indic_plan->is_old_spec ? false : true;
hb_codepoint_t glyphs_r[2] = {glyphs[1], glyphs[0]};
if (indic_plan->blwf.would_substitute (glyphs , 2, zero_context, face) ||
indic_plan->blwf.would_substitute (glyphs_r, 2, zero_context, face))
return POS_BELOW_C;
if (indic_plan->pstf.would_substitute (glyphs , 2, zero_context, face) ||
indic_plan->pstf.would_substitute (glyphs_r, 2, zero_context, face))
return POS_POST_C;
if (indic_plan->pref.would_substitute (glyphs , 2, zero_context, face) ||
indic_plan->pref.would_substitute (glyphs_r, 2, zero_context, face))
return POS_POST_C;
return POS_BASE_C;
}
enum syllable_type_t {
consonant_syllable,
vowel_syllable,
standalone_cluster,
avagraha_cluster,
broken_cluster,
non_indic_cluster,
};
#include "hb-ot-shape-complex-indic-machine.hh"
static void
setup_masks_indic (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_buffer_t *buffer,
hb_font_t *font HB_UNUSED)
{
HB_BUFFER_ALLOCATE_VAR (buffer, indic_category);
HB_BUFFER_ALLOCATE_VAR (buffer, indic_position);
/* We cannot setup masks here. We save information about characters
* and setup masks later on in a pause-callback. */
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
set_indic_properties (buffer->info[i]);
}
static void
setup_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_font_t *font HB_UNUSED,
hb_buffer_t *buffer)
{
find_syllables (buffer);
}
static int
compare_indic_order (const hb_glyph_info_t *pa, const hb_glyph_info_t *pb)
{
int a = pa->indic_position();
int b = pb->indic_position();
return a < b ? -1 : a == b ? 0 : +1;
}
static void
update_consonant_positions (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer)
{
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
hb_codepoint_t glyphs[2];
if (indic_plan->get_virama_glyph (font, &glyphs[0]))
{
hb_face_t *face = font->face;
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
if (buffer->info[i].indic_position() == POS_BASE_C) {
glyphs[1] = buffer->info[i].codepoint;
buffer->info[i].indic_position() = consonant_position_from_face (indic_plan, glyphs, face);
}
}
}
/* Rules from:
* https://www.microsoft.com/typography/otfntdev/devanot/shaping.aspx */
static void
initial_reordering_consonant_syllable (const hb_ot_shape_plan_t *plan,
hb_face_t *face,
hb_buffer_t *buffer,
unsigned int start, unsigned int end)
{
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
hb_glyph_info_t *info = buffer->info;
/* 1. Find base consonant:
*
* The shaping engine finds the base consonant of the syllable, using the
* following algorithm: starting from the end of the syllable, move backwards
* until a consonant is found that does not have a below-base or post-base
* form (post-base forms have to follow below-base forms), or that is not a
* pre-base reordering Ra, or arrive at the first consonant. The consonant
* stopped at will be the base.
*
* o If the syllable starts with Ra + Halant (in a script that has Reph)
* and has more than one consonant, Ra is excluded from candidates for
* base consonants.
*/
unsigned int base = end;
bool has_reph = false;
{
/* -> If the syllable starts with Ra + Halant (in a script that has Reph)
* and has more than one consonant, Ra is excluded from candidates for
* base consonants. */
unsigned int limit = start;
if (indic_plan->mask_array[RPHF] &&
start + 3 <= end &&
(
(indic_plan->config->reph_mode == REPH_MODE_IMPLICIT && !is_joiner (info[start + 2])) ||
(indic_plan->config->reph_mode == REPH_MODE_EXPLICIT && info[start + 2].indic_category() == OT_ZWJ)
))
{
/* See if it matches the 'rphf' feature. */
hb_codepoint_t glyphs[2] = {info[start].codepoint, info[start + 1].codepoint};
if (indic_plan->rphf.would_substitute (glyphs, ARRAY_LENGTH (glyphs), true, face))
{
limit += 2;
while (limit < end && is_joiner (info[limit]))
limit++;
base = start;
has_reph = true;
}
} else if (indic_plan->config->reph_mode == REPH_MODE_LOG_REPHA && info[start].indic_category() == OT_Repha)
{
limit += 1;
while (limit < end && is_joiner (info[limit]))
limit++;
base = start;
has_reph = true;
}
switch (indic_plan->config->base_pos)
{
default:
assert (false);
/* fallthrough */
case BASE_POS_LAST:
{
/* -> starting from the end of the syllable, move backwards */
unsigned int i = end;
bool seen_below = false;
do {
i--;
/* -> until a consonant is found */
if (is_consonant (info[i]))
{
/* -> that does not have a below-base or post-base form
* (post-base forms have to follow below-base forms), */
if (info[i].indic_position() != POS_BELOW_C &&
(info[i].indic_position() != POS_POST_C || seen_below))
{
base = i;
break;
}
if (info[i].indic_position() == POS_BELOW_C)
seen_below = true;
/* -> or that is not a pre-base reordering Ra,
*
* IMPLEMENTATION NOTES:
*
* Our pre-base reordering Ra's are marked POS_POST_C, so will be skipped
* by the logic above already.
*/
/* -> or arrive at the first consonant. The consonant stopped at will
* be the base. */
base = i;
}
else
{
/* A ZWJ after a Halant stops the base search, and requests an explicit
* half form.
* A ZWJ before a Halant, requests a subjoined form instead, and hence
* search continues. This is particularly important for Bengali
* sequence Ra,H,Ya that should form Ya-Phalaa by subjoining Ya. */
if (start < i &&
info[i].indic_category() == OT_ZWJ &&
info[i - 1].indic_category() == OT_H)
break;
}
} while (i > limit);
}
break;
case BASE_POS_FIRST:
{
/* In scripts without half forms (eg. Khmer), the first consonant is always the base. */
if (!has_reph)
base = limit;
/* Find the last base consonant that is not blocked by ZWJ. If there is
* a ZWJ right before a base consonant, that would request a subjoined form. */
for (unsigned int i = limit; i < end; i++)
if (is_consonant (info[i]) && info[i].indic_position() == POS_BASE_C)
{
if (limit < i && info[i - 1].indic_category() == OT_ZWJ)
break;
else
base = i;
}
/* Mark all subsequent consonants as below. */
for (unsigned int i = base + 1; i < end; i++)
if (is_consonant (info[i]) && info[i].indic_position() == POS_BASE_C)
info[i].indic_position() = POS_BELOW_C;
}
break;
}
/* -> If the syllable starts with Ra + Halant (in a script that has Reph)
* and has more than one consonant, Ra is excluded from candidates for
* base consonants.
*
* Only do this for unforced Reph. (ie. not for Ra,H,ZWJ. */
if (has_reph && base == start && limit - base <= 2) {
/* Have no other consonant, so Reph is not formed and Ra becomes base. */
has_reph = false;
}
}
/* 2. Decompose and reorder Matras:
*
* Each matra and any syllable modifier sign in the cluster are moved to the
* appropriate position relative to the consonant(s) in the cluster. The
* shaping engine decomposes two- or three-part matras into their constituent
* parts before any repositioning. Matra characters are classified by which
* consonant in a conjunct they have affinity for and are reordered to the
* following positions:
*
* o Before first half form in the syllable
* o After subjoined consonants
* o After post-form consonant
* o After main consonant (for above marks)
*
* IMPLEMENTATION NOTES:
*
* The normalize() routine has already decomposed matras for us, so we don't
* need to worry about that.
*/
/* 3. Reorder marks to canonical order:
*
* Adjacent nukta and halant or nukta and vedic sign are always repositioned
* if necessary, so that the nukta is first.
*
* IMPLEMENTATION NOTES:
*
* We don't need to do this: the normalize() routine already did this for us.
*/
/* Reorder characters */
for (unsigned int i = start; i < base; i++)
info[i].indic_position() = MIN (POS_PRE_C, (indic_position_t) info[i].indic_position());
if (base < end)
info[base].indic_position() = POS_BASE_C;
/* Mark final consonants. A final consonant is one appearing after a matra,
* like in Khmer. */
for (unsigned int i = base + 1; i < end; i++)
if (info[i].indic_category() == OT_M) {
for (unsigned int j = i + 1; j < end; j++)
if (is_consonant (info[j])) {
info[j].indic_position() = POS_FINAL_C;
break;
}
break;
}
/* Handle beginning Ra */
if (has_reph)
info[start].indic_position() = POS_RA_TO_BECOME_REPH;
/* For old-style Indic script tags, move the first post-base Halant after
* last consonant. Only do this if there is *not* a Halant after last
* consonant. Otherwise it becomes messy. */
if (indic_plan->is_old_spec) {
for (unsigned int i = base + 1; i < end; i++)
if (info[i].indic_category() == OT_H) {
unsigned int j;
for (j = end - 1; j > i; j--)
if (is_consonant (info[j]) || info[j].indic_category() == OT_H)
break;
if (info[j].indic_category() != OT_H && j > i) {
/* Move Halant to after last consonant. */
hb_glyph_info_t t = info[i];
memmove (&info[i], &info[i + 1], (j - i) * sizeof (info[0]));
info[j] = t;
}
break;
}
}
/* Attach misc marks to previous char to move with them. */
{
indic_position_t last_pos = POS_START;
for (unsigned int i = start; i < end; i++)
{
if ((FLAG (info[i].indic_category()) & (JOINER_FLAGS | FLAG (OT_N) | FLAG (OT_RS) | HALANT_OR_COENG_FLAGS)))
{
info[i].indic_position() = last_pos;
if (unlikely (info[i].indic_category() == OT_H &&
info[i].indic_position() == POS_PRE_M))
{
/*
* Uniscribe doesn't move the Halant with Left Matra.
* TEST: U+092B,U+093F,U+094DE
* We follow. This is important for the Sinhala
* U+0DDA split matra since it decomposes to U+0DD9,U+0DCA
* where U+0DD9 is a left matra and U+0DCA is the virama.
* We don't want to move the virama with the left matra.
* TEST: U+0D9A,U+0DDA
*/
for (unsigned int j = i; j > start; j--)
if (info[j - 1].indic_position() != POS_PRE_M) {
info[i].indic_position() = info[j - 1].indic_position();
break;
}
}
} else if (info[i].indic_position() != POS_SMVD) {
last_pos = (indic_position_t) info[i].indic_position();
}
}
}
/* Re-attach ZWJ, ZWNJ, and halant to next char, for after-base consonants. */
{
unsigned int last_halant = end;
for (unsigned int i = base + 1; i < end; i++)
if (is_halant_or_coeng (info[i]))
last_halant = i;
else if (is_consonant (info[i])) {
for (unsigned int j = last_halant; j < i; j++)
if (info[j].indic_position() != POS_SMVD)
info[j].indic_position() = info[i].indic_position();
last_halant = end;
}
}
{
/* Use syllable() for sort accounting temporarily. */
unsigned int syllable = info[start].syllable();
for (unsigned int i = start; i < end; i++)
info[i].syllable() = i - start;
/* Sit tight, rock 'n roll! */
hb_bubble_sort (info + start, end - start, compare_indic_order);
/* Find base again */
base = end;
for (unsigned int i = start; i < end; i++)
if (info[i].indic_position() == POS_BASE_C)
{
base = i;
break;
}
/* Things are out-of-control for post base positions, they may shuffle
* around like crazy. In old-spec mode, we move halants around, so in
* that case merge all clusters after base. Otherwise, check the sort
* order and merge as needed.
* For pre-base stuff, we handle cluster issues in final reordering. */
if (indic_plan->is_old_spec || end - base > 127)
buffer->merge_clusters (base, end);
else
{
/* Note! syllable() is a one-byte field. */
for (unsigned int i = base; i < end; i++)
if (info[i].syllable() != 255)
{
unsigned int max = i;
unsigned int j = start + info[i].syllable();
while (j != i)
{
max = MAX (max, j);
unsigned int next = start + info[j].syllable();
info[j].syllable() = 255; /* So we don't process j later again. */
j = next;
}
if (i != max)
buffer->merge_clusters (i, max + 1);
}
}
/* Put syllable back in. */
for (unsigned int i = start; i < end; i++)
info[i].syllable() = syllable;
}
/* Setup masks now */
{
hb_mask_t mask;
/* Reph */
for (unsigned int i = start; i < end && info[i].indic_position() == POS_RA_TO_BECOME_REPH; i++)
info[i].mask |= indic_plan->mask_array[RPHF];
/* Pre-base */
mask = indic_plan->mask_array[HALF];
if (!indic_plan->is_old_spec &&
indic_plan->config->blwf_mode == BLWF_MODE_PRE_AND_POST)
mask |= indic_plan->mask_array[BLWF];
for (unsigned int i = start; i < base; i++)
info[i].mask |= mask;
/* Base */
mask = 0;
if (base < end)
info[base].mask |= mask;
/* Post-base */
mask = indic_plan->mask_array[BLWF] | indic_plan->mask_array[ABVF] | indic_plan->mask_array[PSTF];
for (unsigned int i = base + 1; i < end; i++)
info[i].mask |= mask;
}
if (indic_plan->is_old_spec &&
buffer->props.script == HB_SCRIPT_DEVANAGARI)
{
/* Old-spec eye-lash Ra needs special handling. From the
* spec:
*
* "The feature 'below-base form' is applied to consonants
* having below-base forms and following the base consonant.
* The exception is vattu, which may appear below half forms
* as well as below the base glyph. The feature 'below-base
* form' will be applied to all such occurrences of Ra as well."
*
* Test case: U+0924,U+094D,U+0930,U+094d,U+0915
* with Sanskrit 2003 font.
*
* However, note that Ra,Halant,ZWJ is the correct way to
* request eyelash form of Ra, so we wouldbn't inhibit it
* in that sequence.
*
* Test case: U+0924,U+094D,U+0930,U+094d,U+200D,U+0915
*/
for (unsigned int i = start; i + 1 < base; i++)
if (info[i ].indic_category() == OT_Ra &&
info[i+1].indic_category() == OT_H &&
(i + 2 == base ||
info[i+2].indic_category() != OT_ZWJ))
{
info[i ].mask |= indic_plan->mask_array[BLWF];
info[i+1].mask |= indic_plan->mask_array[BLWF];
}
}
if (indic_plan->mask_array[PREF] && base + 2 < end)
{
/* Find a Halant,Ra sequence and mark it for pre-base reordering processing. */
for (unsigned int i = base + 1; i + 1 < end; i++) {
hb_codepoint_t glyphs[2] = {info[i].codepoint, info[i + 1].codepoint};
if (indic_plan->pref.would_substitute (glyphs, ARRAY_LENGTH (glyphs), true, face))
{
info[i++].mask |= indic_plan->mask_array[PREF];
info[i++].mask |= indic_plan->mask_array[PREF];
/* Mark the subsequent stuff with 'cfar'. Used in Khmer.
* Read the feature spec.
* This allows distinguishing the following cases with MS Khmer fonts:
* U+1784,U+17D2,U+179A,U+17D2,U+1782
* U+1784,U+17D2,U+1782,U+17D2,U+179A
*/
for (; i < end; i++)
info[i].mask |= indic_plan->mask_array[CFAR];
break;
}
}
}
/* Apply ZWJ/ZWNJ effects */
for (unsigned int i = start + 1; i < end; i++)
if (is_joiner (info[i])) {
bool non_joiner = info[i].indic_category() == OT_ZWNJ;
unsigned int j = i;
do {
j--;
/* ZWJ/ZWNJ should disable CJCT. They do that by simply
* being there, since we don't skip them for the CJCT
* feature (ie. F_MANUAL_ZWJ) */
/* A ZWNJ disables HALF. */
if (non_joiner)
info[j].mask &= ~indic_plan->mask_array[HALF];
} while (j > start && !is_consonant (info[j]));
}
}
static void
initial_reordering_vowel_syllable (const hb_ot_shape_plan_t *plan,
hb_face_t *face,
hb_buffer_t *buffer,
unsigned int start, unsigned int end)
{
/* We made the vowels look like consonants. So let's call the consonant logic! */
initial_reordering_consonant_syllable (plan, face, buffer, start, end);
}
static void
initial_reordering_standalone_cluster (const hb_ot_shape_plan_t *plan,
hb_face_t *face,
hb_buffer_t *buffer,
unsigned int start, unsigned int end)
{
/* We treat NBSP/dotted-circle as if they are consonants, so we should just chain.
* Only if not in compatibility mode that is... */
if (hb_options ().uniscribe_bug_compatible)
{
/* For dotted-circle, this is what Uniscribe does:
* If dotted-circle is the last glyph, it just does nothing.
* Ie. It doesn't form Reph. */
if (buffer->info[end - 1].indic_category() == OT_DOTTEDCIRCLE)
return;
}
initial_reordering_consonant_syllable (plan, face, buffer, start, end);
}
static void
initial_reordering_broken_cluster (const hb_ot_shape_plan_t *plan,
hb_face_t *face,
hb_buffer_t *buffer,
unsigned int start, unsigned int end)
{
/* We already inserted dotted-circles, so just call the standalone_cluster. */
initial_reordering_standalone_cluster (plan, face, buffer, start, end);
}
static void
initial_reordering_avagraha_cluster (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_face_t *face HB_UNUSED,
hb_buffer_t *buffer HB_UNUSED,
unsigned int start HB_UNUSED, unsigned int end HB_UNUSED)
{
/* Nothing to do right now. If we ever switch to using the output
* buffer in the reordering process, we'd need to next_glyph() here. */
}
static void
initial_reordering_non_indic_cluster (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_face_t *face HB_UNUSED,
hb_buffer_t *buffer HB_UNUSED,
unsigned int start HB_UNUSED, unsigned int end HB_UNUSED)
{
/* Nothing to do right now. If we ever switch to using the output
* buffer in the reordering process, we'd need to next_glyph() here. */
}
static void
initial_reordering_syllable (const hb_ot_shape_plan_t *plan,
hb_face_t *face,
hb_buffer_t *buffer,
unsigned int start, unsigned int end)
{
syllable_type_t syllable_type = (syllable_type_t) (buffer->info[start].syllable() & 0x0F);
switch (syllable_type) {
case consonant_syllable: initial_reordering_consonant_syllable (plan, face, buffer, start, end); return;
case vowel_syllable: initial_reordering_vowel_syllable (plan, face, buffer, start, end); return;
case standalone_cluster: initial_reordering_standalone_cluster (plan, face, buffer, start, end); return;
case avagraha_cluster: initial_reordering_avagraha_cluster (plan, face, buffer, start, end); return;
case broken_cluster: initial_reordering_broken_cluster (plan, face, buffer, start, end); return;
case non_indic_cluster: initial_reordering_non_indic_cluster (plan, face, buffer, start, end); return;
}
}
static inline void
insert_dotted_circles (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_font_t *font,
hb_buffer_t *buffer)
{
/* Note: This loop is extra overhead, but should not be measurable. */
bool has_broken_syllables = false;
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
if ((buffer->info[i].syllable() & 0x0F) == broken_cluster) {
has_broken_syllables = true;
break;
}
if (likely (!has_broken_syllables))
return;
hb_codepoint_t dottedcircle_glyph;
if (!font->get_glyph (0x25CC, 0, &dottedcircle_glyph))
return;
hb_glyph_info_t dottedcircle = {0};
dottedcircle.codepoint = 0x25CC;
set_indic_properties (dottedcircle);
dottedcircle.codepoint = dottedcircle_glyph;
buffer->clear_output ();
buffer->idx = 0;
unsigned int last_syllable = 0;
while (buffer->idx < buffer->len)
{
unsigned int syllable = buffer->cur().syllable();
syllable_type_t syllable_type = (syllable_type_t) (syllable & 0x0F);
if (unlikely (last_syllable != syllable && syllable_type == broken_cluster))
{
last_syllable = syllable;
hb_glyph_info_t info = dottedcircle;
info.cluster = buffer->cur().cluster;
info.mask = buffer->cur().mask;
info.syllable() = buffer->cur().syllable();
/* Insert dottedcircle after possible Repha. */
while (buffer->idx < buffer->len &&
last_syllable == buffer->cur().syllable() &&
buffer->cur().indic_category() == OT_Repha)
buffer->next_glyph ();
buffer->output_info (info);
}
else
buffer->next_glyph ();
}
buffer->swap_buffers ();
}
static void
initial_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font,
hb_buffer_t *buffer)
{
update_consonant_positions (plan, font, buffer);
insert_dotted_circles (plan, font, buffer);
hb_glyph_info_t *info = buffer->info;
unsigned int count = buffer->len;
if (unlikely (!count)) return;
unsigned int last = 0;
unsigned int last_syllable = info[0].syllable();
for (unsigned int i = 1; i < count; i++)
if (last_syllable != info[i].syllable()) {
initial_reordering_syllable (plan, font->face, buffer, last, i);
last = i;
last_syllable = info[last].syllable();
}
initial_reordering_syllable (plan, font->face, buffer, last, count);
}
static void
final_reordering_syllable (const hb_ot_shape_plan_t *plan,
hb_buffer_t *buffer,
unsigned int start, unsigned int end)
{
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
hb_glyph_info_t *info = buffer->info;
/* 4. Final reordering:
*
* After the localized forms and basic shaping forms GSUB features have been
* applied (see below), the shaping engine performs some final glyph
* reordering before applying all the remaining font features to the entire
* cluster.
*/
/* Find base again */
unsigned int base;
for (base = start; base < end; base++)
if (info[base].indic_position() >= POS_BASE_C) {
if (start < base && info[base].indic_position() > POS_BASE_C)
base--;
break;
}
if (base == end && start < base &&
info[base - 1].indic_category() != OT_ZWJ)
base--;
while (start < base &&
(info[base].indic_category() == OT_H ||
info[base].indic_category() == OT_N))
base--;
/* o Reorder matras:
*
* If a pre-base matra character had been reordered before applying basic
* features, the glyph can be moved closer to the main consonant based on
* whether half-forms had been formed. Actual position for the matra is
* defined as “after last standalone halant glyph, after initial matra
* position and before the main consonant”. If ZWJ or ZWNJ follow this
* halant, position is moved after it.
*/
if (start + 1 < end && start < base) /* Otherwise there can't be any pre-base matra characters. */
{
/* If we lost track of base, alas, position before last thingy. */
unsigned int new_pos = base == end ? base - 2 : base - 1;
/* Malayalam / Tamil do not have "half" forms or explicit virama forms.
* The glyphs formed by 'half' are Chillus or ligated explicit viramas.
* We want to position matra after them.
*/
if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
{
while (new_pos > start &&
!(is_one_of (info[new_pos], (FLAG (OT_M) | FLAG (OT_H) | FLAG (OT_Coeng)))))
new_pos--;
/* If we found no Halant we are done.
* Otherwise only proceed if the Halant does
* not belong to the Matra itself! */
if (is_halant_or_coeng (info[new_pos]) &&
info[new_pos].indic_position() != POS_PRE_M)
{
/* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
if (new_pos + 1 < end && is_joiner (info[new_pos + 1]))
new_pos++;
}
else
new_pos = start; /* No move. */
}
if (start < new_pos && info[new_pos].indic_position () != POS_PRE_M)
{
/* Now go see if there's actually any matras... */
for (unsigned int i = new_pos; i > start; i--)
if (info[i - 1].indic_position () == POS_PRE_M)
{
unsigned int old_pos = i - 1;
hb_glyph_info_t tmp = info[old_pos];
memmove (&info[old_pos], &info[old_pos + 1], (new_pos - old_pos) * sizeof (info[0]));
info[new_pos] = tmp;
if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */
base--;
buffer->merge_clusters (new_pos, MIN (end, base + 1));
new_pos--;
}
} else {
for (unsigned int i = start; i < base; i++)
if (info[i].indic_position () == POS_PRE_M) {
buffer->merge_clusters (i, MIN (end, base + 1));
break;
}
}
}
/* o Reorder reph:
*
* Reph’s original position is always at the beginning of the syllable,
* (i.e. it is not reordered at the character reordering stage). However,
* it will be reordered according to the basic-forms shaping results.
* Possible positions for reph, depending on the script, are; after main,
* before post-base consonant forms, and after post-base consonant forms.
*/
/* Two cases:
*
* - If repha is encoded as a sequence of characters (Ra,H or Ra,H,ZWJ), then
* we should only move it if the sequence ligated to the repha form.
*
* - If repha is encoded separately and in the logical position, we should only
* move it if it did NOT ligate. If it ligated, it's probably the font trying
* to make it work without the reordering.
*/
if (start + 1 < end &&
info[start].indic_position() == POS_RA_TO_BECOME_REPH &&
((info[start].indic_category() == OT_Repha) ^ is_a_ligature (info[start])))
{
unsigned int new_reph_pos;
reph_position_t reph_pos = indic_plan->config->reph_pos;
/* 1. If reph should be positioned after post-base consonant forms,
* proceed to step 5.
*/
if (reph_pos == REPH_POS_AFTER_POST)
{
goto reph_step_5;
}
/* 2. If the reph repositioning class is not after post-base: target
* position is after the first explicit halant glyph between the
* first post-reph consonant and last main consonant. If ZWJ or ZWNJ
* are following this halant, position is moved after it. If such
* position is found, this is the target position. Otherwise,
* proceed to the next step.
*
* Note: in old-implementation fonts, where classifications were
* fixed in shaping engine, there was no case where reph position
* will be found on this step.
*/
{
new_reph_pos = start + 1;
while (new_reph_pos < base && !is_halant_or_coeng (info[new_reph_pos]))
new_reph_pos++;
if (new_reph_pos < base && is_halant_or_coeng (info[new_reph_pos]))
{
/* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
new_reph_pos++;
goto reph_move;
}
}
/* 3. If reph should be repositioned after the main consonant: find the
* first consonant not ligated with main, or find the first
* consonant that is not a potential pre-base reordering Ra.
*/
if (reph_pos == REPH_POS_AFTER_MAIN)
{
new_reph_pos = base;
while (new_reph_pos + 1 < end && info[new_reph_pos + 1].indic_position() <= POS_AFTER_MAIN)
new_reph_pos++;
if (new_reph_pos < end)
goto reph_move;
}
/* 4. If reph should be positioned before post-base consonant, find
* first post-base classified consonant not ligated with main. If no
* consonant is found, the target position should be before the
* first matra, syllable modifier sign or vedic sign.
*/
/* This is our take on what step 4 is trying to say (and failing, BADLY). */
if (reph_pos == REPH_POS_AFTER_SUB)
{
new_reph_pos = base;
while (new_reph_pos < end &&
!( FLAG (info[new_reph_pos + 1].indic_position()) & (FLAG (POS_POST_C) | FLAG (POS_AFTER_POST) | FLAG (POS_SMVD))))
new_reph_pos++;
if (new_reph_pos < end)
goto reph_move;
}
/* 5. If no consonant is found in steps 3 or 4, move reph to a position
* immediately before the first post-base matra, syllable modifier
* sign or vedic sign that has a reordering class after the intended
* reph position. For example, if the reordering position for reph
* is post-main, it will skip above-base matras that also have a
* post-main position.
*/
reph_step_5:
{
/* Copied from step 2. */
new_reph_pos = start + 1;
while (new_reph_pos < base && !is_halant_or_coeng (info[new_reph_pos]))
new_reph_pos++;
if (new_reph_pos < base && is_halant_or_coeng (info[new_reph_pos]))
{
/* ->If ZWJ or ZWNJ are following this halant, position is moved after it. */
if (new_reph_pos + 1 < base && is_joiner (info[new_reph_pos + 1]))
new_reph_pos++;
goto reph_move;
}
}
/* 6. Otherwise, reorder reph to the end of the syllable.
*/
{
new_reph_pos = end - 1;
while (new_reph_pos > start && info[new_reph_pos].indic_position() == POS_SMVD)
new_reph_pos--;
/*
* If the Reph is to be ending up after a Matra,Halant sequence,
* position it before that Halant so it can interact with the Matra.
* However, if it's a plain Consonant,Halant we shouldn't do that.
* Uniscribe doesn't do this.
* TEST: U+0930,U+094D,U+0915,U+094B,U+094D
*/
if (!hb_options ().uniscribe_bug_compatible &&
unlikely (is_halant_or_coeng (info[new_reph_pos]))) {
for (unsigned int i = base + 1; i < new_reph_pos; i++)
if (info[i].indic_category() == OT_M) {
/* Ok, got it. */
new_reph_pos--;
}
}
goto reph_move;
}
reph_move:
{
buffer->merge_clusters (start, new_reph_pos + 1);
/* Move */
hb_glyph_info_t reph = info[start];
memmove (&info[start], &info[start + 1], (new_reph_pos - start) * sizeof (info[0]));
info[new_reph_pos] = reph;
if (start < base && base <= new_reph_pos)
base--;
}
}
/* o Reorder pre-base reordering consonants:
*
* If a pre-base reordering consonant is found, reorder it according to
* the following rules:
*/
if (indic_plan->mask_array[PREF] && base + 1 < end) /* Otherwise there can't be any pre-base reordering Ra. */
{
for (unsigned int i = base + 1; i < end; i++)
if ((info[i].mask & indic_plan->mask_array[PREF]) != 0)
{
/* 1. Only reorder a glyph produced by substitution during application
* of the <pref> feature. (Note that a font may shape a Ra consonant with
* the feature generally but block it in certain contexts.)
*/
if (i + 1 == end || (info[i + 1].mask & indic_plan->mask_array[PREF]) == 0)
{
/*
* 2. Try to find a target position the same way as for pre-base matra.
* If it is found, reorder pre-base consonant glyph.
*
* 3. If position is not found, reorder immediately before main
* consonant.
*/
unsigned int new_pos = base;
/* Malayalam / Tamil do not have "half" forms or explicit virama forms.
* The glyphs formed by 'half' are Chillus or ligated explicit viramas.
* We want to position matra after them.
*/
if (buffer->props.script != HB_SCRIPT_MALAYALAM && buffer->props.script != HB_SCRIPT_TAMIL)
{
while (new_pos > start &&
!(is_one_of (info[new_pos - 1], FLAG(OT_M) | HALANT_OR_COENG_FLAGS)))
new_pos--;
/* In Khmer coeng model, a V,Ra can go *after* matras. If it goes after a
* split matra, it should be reordered to *before* the left part of such matra. */
if (new_pos > start && info[new_pos - 1].indic_category() == OT_M)
{
unsigned int old_pos = i;
for (unsigned int i = base + 1; i < old_pos; i++)
if (info[i].indic_category() == OT_M)
{
new_pos--;
break;
}
}
}
if (new_pos > start && is_halant_or_coeng (info[new_pos - 1]))
{
/* -> If ZWJ or ZWNJ follow this halant, position is moved after it. */
if (new_pos < end && is_joiner (info[new_pos]))
new_pos++;
}
{
unsigned int old_pos = i;
buffer->merge_clusters (new_pos, old_pos + 1);
hb_glyph_info_t tmp = info[old_pos];
memmove (&info[new_pos + 1], &info[new_pos], (old_pos - new_pos) * sizeof (info[0]));
info[new_pos] = tmp;
if (new_pos <= base && base < old_pos)
base++;
}
}
break;
}
}
/* Apply 'init' to the Left Matra if it's a word start. */
if (info[start].indic_position () == POS_PRE_M &&
(!start ||
!(FLAG (_hb_glyph_info_get_general_category (&info[start - 1])) &
FLAG_RANGE (HB_UNICODE_GENERAL_CATEGORY_FORMAT, HB_UNICODE_GENERAL_CATEGORY_NON_SPACING_MARK))))
info[start].mask |= indic_plan->mask_array[INIT];
/*
* Finish off the clusters and go home!
*/
if (hb_options ().uniscribe_bug_compatible && buffer->props.script != HB_SCRIPT_TAMIL)
{
/* Uniscribe merges the entire cluster... Except for Tamil.
* This means, half forms are submerged into the main consonants cluster.
* This is unnecessary, and makes cursor positioning harder, but that's what
* Uniscribe does. */
buffer->merge_clusters (start, end);
}
}
static void
final_reordering (const hb_ot_shape_plan_t *plan,
hb_font_t *font HB_UNUSED,
hb_buffer_t *buffer)
{
unsigned int count = buffer->len;
if (unlikely (!count)) return;
hb_glyph_info_t *info = buffer->info;
unsigned int last = 0;
unsigned int last_syllable = info[0].syllable();
for (unsigned int i = 1; i < count; i++)
if (last_syllable != info[i].syllable()) {
final_reordering_syllable (plan, buffer, last, i);
last = i;
last_syllable = info[last].syllable();
}
final_reordering_syllable (plan, buffer, last, count);
HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
}
static void
clear_syllables (const hb_ot_shape_plan_t *plan HB_UNUSED,
hb_font_t *font HB_UNUSED,
hb_buffer_t *buffer)
{
hb_glyph_info_t *info = buffer->info;
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
info[i].syllable() = 0;
}
static hb_ot_shape_normalization_mode_t
normalization_preference_indic (const hb_segment_properties_t *props HB_UNUSED)
{
return HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT;
}
static bool
decompose_indic (const hb_ot_shape_normalize_context_t *c,
hb_codepoint_t ab,
hb_codepoint_t *a,
hb_codepoint_t *b)
{
switch (ab)
{
/* Don't decompose these. */
case 0x0931 : return false;
case 0x0B94 : return false;
/*
* Decompose split matras that don't have Unicode decompositions.
*/
case 0x0F77 : *a = 0x0FB2; *b= 0x0F81; return true;
case 0x0F79 : *a = 0x0FB3; *b= 0x0F81; return true;
case 0x17BE : *a = 0x17C1; *b= 0x17BE; return true;
case 0x17BF : *a = 0x17C1; *b= 0x17BF; return true;
case 0x17C0 : *a = 0x17C1; *b= 0x17C0; return true;
case 0x17C4 : *a = 0x17C1; *b= 0x17C4; return true;
case 0x17C5 : *a = 0x17C1; *b= 0x17C5; return true;
case 0x1925 : *a = 0x1920; *b= 0x1923; return true;
case 0x1926 : *a = 0x1920; *b= 0x1924; return true;
case 0x1B3C : *a = 0x1B42; *b= 0x1B3C; return true;
case 0x1112E : *a = 0x11127; *b= 0x11131; return true;
case 0x1112F : *a = 0x11127; *b= 0x11132; return true;
#if 0
/* This one has no decomposition in Unicode, but needs no decomposition either. */
/* case 0x0AC9 : return false; */
case 0x0B57 : *a = no decomp, -> RIGHT; return true;
case 0x1C29 : *a = no decomp, -> LEFT; return true;
case 0xA9C0 : *a = no decomp, -> RIGHT; return true;
case 0x111BF : *a = no decomp, -> ABOVE; return true;
#endif
}
if ((ab == 0x0DDA || hb_in_range<hb_codepoint_t> (ab, 0x0DDC, 0x0DDE)))
{
/*
* Sinhala split matras... Let the fun begin.
*
* These four characters have Unicode decompositions. However, Uniscribe
* decomposes them "Khmer-style", that is, it uses the character itself to
* get the second half. The first half of all four decompositions is always
* U+0DD9.
*
* Now, there are buggy fonts, namely, the widely used lklug.ttf, that are
* broken with Uniscribe. But we need to support them. As such, we only
* do the Uniscribe-style decomposition if the character is transformed into
* its "sec.half" form by the 'pstf' feature. Otherwise, we fall back to
* Unicode decomposition.
*
* Note that we can't unconditionally use Unicode decomposition. That would
* break some other fonts, that are designed to work with Uniscribe, and
* don't have positioning features for the Unicode-style decomposition.
*
* Argh...
*
* The Uniscribe behavior is now documented in the newly published Sinhala
* spec in 2012:
*
* http://www.microsoft.com/typography/OpenTypeDev/sinhala/intro.htm#shaping
*/
const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) c->plan->data;
hb_codepoint_t glyph;
if (hb_options ().uniscribe_bug_compatible ||
(c->font->get_glyph (ab, 0, &glyph) &&
indic_plan->pstf.would_substitute (&glyph, 1, true, c->font->face)))
{
/* Ok, safe to use Uniscribe-style decomposition. */
*a = 0x0DD9;
*b = ab;
return true;
}
}
return c->unicode->decompose (ab, a, b);
}
static bool
compose_indic (const hb_ot_shape_normalize_context_t *c,
hb_codepoint_t a,
hb_codepoint_t b,
hb_codepoint_t *ab)
{
/* Avoid recomposing split matras. */
if (HB_UNICODE_GENERAL_CATEGORY_IS_MARK (c->unicode->general_category (a)))
return false;
/* Composition-exclusion exceptions that we want to recompose. */
if (a == 0x09AF && b == 0x09BC) { *ab = 0x09DF; return true; }
return c->unicode->compose (a, b, ab);
}
const hb_ot_complex_shaper_t _hb_ot_complex_shaper_indic =
{
"indic",
collect_features_indic,
override_features_indic,
data_create_indic,
data_destroy_indic,
NULL, /* preprocess_text */
normalization_preference_indic,
decompose_indic,
compose_indic,
setup_masks_indic,
HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
false, /* fallback_position */
};
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