Rename s/shape-complex/shaper/g
diff --git a/src/hb-ot-shaper-indic.cc b/src/hb-ot-shaper-indic.cc
new file mode 100644
index 0000000..2c8f7c5
--- /dev/null
+++ b/src/hb-ot-shaper-indic.cc
@@ -0,0 +1,1570 @@
+/*
+ * 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.hh"
+
+#ifndef HB_NO_OT_SHAPE
+
+#include "hb-ot-shaper-indic.hh"
+#include "hb-ot-shaper-indic-machine.hh"
+#include "hb-ot-shaper-vowel-constraints.hh"
+#include "hb-ot-layout.hh"
+
+
+/*
+ * Indic shaper.
+ */
+
+
+/*
+ * 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_LAST_SINHALA,
+ BASE_POS_LAST
+};
+enum reph_position_t {
+ 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_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_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
+ {HB_SCRIPT_DEVANAGARI,true, 0x094Du,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
+ {HB_SCRIPT_BENGALI, true, 0x09CDu,BASE_POS_LAST, REPH_POS_AFTER_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
+ {HB_SCRIPT_GURMUKHI, true, 0x0A4Du,BASE_POS_LAST, REPH_POS_BEFORE_SUB, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
+ {HB_SCRIPT_GUJARATI, true, 0x0ACDu,BASE_POS_LAST, REPH_POS_BEFORE_POST,REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
+ {HB_SCRIPT_ORIYA, true, 0x0B4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
+ {HB_SCRIPT_TAMIL, true, 0x0BCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_PRE_AND_POST},
+ {HB_SCRIPT_TELUGU, true, 0x0C4Du,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_POST_ONLY},
+ {HB_SCRIPT_KANNADA, true, 0x0CCDu,BASE_POS_LAST, REPH_POS_AFTER_POST, REPH_MODE_IMPLICIT, BLWF_MODE_POST_ONLY},
+ {HB_SCRIPT_MALAYALAM, true, 0x0D4Du,BASE_POS_LAST, REPH_POS_AFTER_MAIN, REPH_MODE_LOG_REPHA,BLWF_MODE_PRE_AND_POST},
+ {HB_SCRIPT_SINHALA, false,0x0DCAu,BASE_POS_LAST_SINHALA,
+ REPH_POS_AFTER_POST, REPH_MODE_EXPLICIT, BLWF_MODE_PRE_AND_POST},
+};
+
+
+
+/*
+ * Indic shaper.
+ */
+
+static const hb_ot_map_feature_t
+indic_features[] =
+{
+ /*
+ * Basic features.
+ * These features are applied in order, one at a time, after initial_reordering,
+ * constrained to the syllable.
+ */
+ {HB_TAG('n','u','k','t'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('a','k','h','n'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('r','p','h','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('r','k','r','f'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('p','r','e','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('b','l','w','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('a','b','v','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('h','a','l','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('p','s','t','f'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('v','a','t','u'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('c','j','c','t'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ /*
+ * Other features.
+ * These features are applied all at once, after final_reordering, constrained
+ * to the syllable.
+ * Default Bengali font in Windows for example has intermixed
+ * lookups for init,pres,abvs,blws features.
+ */
+ {HB_TAG('i','n','i','t'), F_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('p','r','e','s'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('a','b','v','s'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('b','l','w','s'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('p','s','t','s'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+ {HB_TAG('h','a','l','n'), F_GLOBAL_MANUAL_JOINERS | F_PER_SYLLABLE},
+};
+
+/*
+ * Must be in the same order as the indic_features array.
+ */
+enum {
+ _INDIC_NUKT,
+ _INDIC_AKHN,
+ INDIC_RPHF,
+ _INDIC_RKRF,
+ INDIC_PREF,
+ INDIC_BLWF,
+ INDIC_ABVF,
+ INDIC_HALF,
+ INDIC_PSTF,
+ _INDIC_VATU,
+ _INDIC_CJCT,
+
+ INDIC_INIT,
+ _INDIC_PRES,
+ _INDIC_ABVS,
+ _INDIC_BLWS,
+ _INDIC_PSTS,
+ _INDIC_HALN,
+
+ INDIC_NUM_FEATURES,
+ INDIC_BASIC_FEATURES = INDIC_INIT, /* Don't forget to update this! */
+};
+
+static void
+setup_syllables_indic (const hb_ot_shape_plan_t *plan,
+ hb_font_t *font,
+ hb_buffer_t *buffer);
+static void
+initial_reordering_indic (const hb_ot_shape_plan_t *plan,
+ hb_font_t *font,
+ hb_buffer_t *buffer);
+static void
+final_reordering_indic (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_indic);
+
+ map->enable_feature (HB_TAG('l','o','c','l'), F_PER_SYLLABLE);
+ /* 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->enable_feature (HB_TAG('c','c','m','p'), F_PER_SYLLABLE);
+
+
+ unsigned int i = 0;
+ map->add_gsub_pause (initial_reordering_indic);
+
+ for (; i < INDIC_BASIC_FEATURES; i++) {
+ map->add_feature (indic_features[i]);
+ map->add_gsub_pause (nullptr);
+ }
+
+ map->add_gsub_pause (final_reordering_indic);
+
+ for (; i < INDIC_NUM_FEATURES; i++)
+ map->add_feature (indic_features[i]);
+}
+
+static void
+override_features_indic (hb_ot_shape_planner_t *plan)
+{
+ plan->map.disable_feature (HB_TAG('l','i','g','a'));
+}
+
+
+struct indic_shape_plan_t
+{
+ bool load_virama_glyph (hb_font_t *font, hb_codepoint_t *pglyph) const
+ {
+ hb_codepoint_t glyph = virama_glyph.get_relaxed ();
+ if (unlikely (glyph == (hb_codepoint_t) -1))
+ {
+ if (!config->virama || !font->get_nominal_glyph (config->virama, &glyph))
+ glyph = 0;
+ /* Technically speaking, the spec says we should apply 'locl' to virama too.
+ * Maybe one day... */
+
+ /* Our get_nominal_glyph() function needs a font, so we can't get the virama glyph
+ * during shape planning... Instead, overwrite it here. */
+ virama_glyph.set_relaxed ((int) glyph);
+ }
+
+ *pglyph = glyph;
+ return glyph != 0;
+ }
+
+ const indic_config_t *config;
+
+ bool is_old_spec;
+#ifndef HB_NO_UNISCRIBE_BUG_COMPATIBLE
+ bool uniscribe_bug_compatible;
+#else
+ static constexpr bool uniscribe_bug_compatible = false;
+#endif
+ mutable hb_atomic_int_t virama_glyph;
+
+ hb_indic_would_substitute_feature_t rphf;
+ hb_indic_would_substitute_feature_t pref;
+ hb_indic_would_substitute_feature_t blwf;
+ hb_indic_would_substitute_feature_t pstf;
+ hb_indic_would_substitute_feature_t vatu;
+
+ 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 *) hb_calloc (1, sizeof (indic_shape_plan_t));
+ if (unlikely (!indic_plan))
+ return nullptr;
+
+ 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] & 0x000000FFu) != '2');
+#ifndef HB_NO_UNISCRIBE_BUG_COMPATIBLE
+ indic_plan->uniscribe_bug_compatible = hb_options ().uniscribe_bug_compatible;
+#endif
+ indic_plan->virama_glyph.set_relaxed (-1);
+
+ /* Use zero-context would_substitute() matching for new-spec of the main
+ * Indic scripts, and scripts with one spec only, but not for old-specs.
+ * The new-spec for all dual-spec scripts says zero-context matching happens.
+ *
+ * However, testing with Malayalam shows that old and new spec both allow
+ * context. Testing with Bengali new-spec however shows that it doesn't.
+ * So, the heuristic here is the way it is. It should *only* be changed,
+ * as we discover more cases of what Windows does. DON'T TOUCH OTHERWISE.
+ */
+ bool zero_context = !indic_plan->is_old_spec && plan->props.script != HB_SCRIPT_MALAYALAM;
+ indic_plan->rphf.init (&plan->map, HB_TAG('r','p','h','f'), zero_context);
+ indic_plan->pref.init (&plan->map, HB_TAG('p','r','e','f'), zero_context);
+ indic_plan->blwf.init (&plan->map, HB_TAG('b','l','w','f'), zero_context);
+ indic_plan->pstf.init (&plan->map, HB_TAG('p','s','t','f'), zero_context);
+ indic_plan->vatu.init (&plan->map, HB_TAG('v','a','t','u'), zero_context);
+
+ 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)
+{
+ hb_free (data);
+}
+
+static indic_position_t
+consonant_position_from_face (const indic_shape_plan_t *indic_plan,
+ const hb_codepoint_t consonant,
+ const hb_codepoint_t virama,
+ 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.
+ *
+ * Vatu is done as well, for:
+ * https://github.com/harfbuzz/harfbuzz/issues/1587
+ */
+ hb_codepoint_t glyphs[3] = {virama, consonant, virama};
+ if (indic_plan->blwf.would_substitute (glyphs , 2, face) ||
+ indic_plan->blwf.would_substitute (glyphs+1, 2, face) ||
+ indic_plan->vatu.would_substitute (glyphs , 2, face) ||
+ indic_plan->vatu.would_substitute (glyphs+1, 2, face))
+ return POS_BELOW_C;
+ if (indic_plan->pstf.would_substitute (glyphs , 2, face) ||
+ indic_plan->pstf.would_substitute (glyphs+1, 2, face))
+ return POS_POST_C;
+ if (indic_plan->pref.would_substitute (glyphs , 2, face) ||
+ indic_plan->pref.would_substitute (glyphs+1, 2, face))
+ return POS_POST_C;
+ return POS_BASE_C;
+}
+
+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;
+ hb_glyph_info_t *info = buffer->info;
+ for (unsigned int i = 0; i < count; i++)
+ set_indic_properties (info[i]);
+}
+
+static void
+setup_syllables_indic (const hb_ot_shape_plan_t *plan HB_UNUSED,
+ hb_font_t *font HB_UNUSED,
+ hb_buffer_t *buffer)
+{
+ find_syllables_indic (buffer);
+ foreach_syllable (buffer, start, end)
+ buffer->unsafe_to_break (start, end);
+}
+
+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_indic (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;
+
+ if (indic_plan->config->base_pos != BASE_POS_LAST)
+ return;
+
+ hb_codepoint_t virama;
+ if (indic_plan->load_virama_glyph (font, &virama))
+ {
+ hb_face_t *face = font->face;
+ unsigned int count = buffer->len;
+ hb_glyph_info_t *info = buffer->info;
+ for (unsigned int i = 0; i < count; i++)
+ if (info[i].indic_position() == POS_BASE_C)
+ {
+ hb_codepoint_t consonant = info[i].codepoint;
+ info[i].indic_position() = consonant_position_from_face (indic_plan, consonant, virama, face);
+ }
+ }
+}
+
+
+/* Rules from:
+ * https://docs.microsqoft.com/en-us/typography/script-development/devanagari */
+
+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;
+
+ /* https://github.com/harfbuzz/harfbuzz/issues/435#issuecomment-335560167
+ * // For compatibility with legacy usage in Kannada,
+ * // Ra+h+ZWJ must behave like Ra+ZWJ+h...
+ */
+ if (buffer->props.script == HB_SCRIPT_KANNADA &&
+ start + 3 <= end &&
+ is_one_of (info[start ], FLAG (OT_Ra)) &&
+ is_one_of (info[start+1], FLAG (OT_H)) &&
+ is_one_of (info[start+2], FLAG (OT_ZWJ)))
+ {
+ buffer->merge_clusters (start+1, start+3);
+ hb_glyph_info_t tmp = info[start+1];
+ info[start+1] = info[start+2];
+ info[start+2] = tmp;
+ }
+
+ /* 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[INDIC_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[3] = {info[start].codepoint,
+ info[start + 1].codepoint,
+ indic_plan->config->reph_mode == REPH_MODE_EXPLICIT ?
+ info[start + 2].codepoint : 0};
+ if (indic_plan->rphf.would_substitute (glyphs, 2, face) ||
+ (indic_plan->config->reph_mode == REPH_MODE_EXPLICIT &&
+ indic_plan->rphf.would_substitute (glyphs, 3, 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)
+ {
+ 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_LAST_SINHALA:
+ {
+ /* Sinhala base positioning is slightly different from main Indic, in that:
+ * 1. Its ZWJ behavior is different,
+ * 2. We don't need to look into the font for consonant positions.
+ */
+
+ 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]))
+ {
+ 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_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 syllable are moved to the
+ * appropriate position relative to the consonant(s) in the syllable. 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() = hb_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.
+ * Happens in Sinhala. */
+ 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.
+ *
+ * Reports suggest that in some scripts Uniscribe does this only if there
+ * is *not* a Halant after last consonant already. We know that is the
+ * case for Kannada, while it reorders unconditionally in other scripts,
+ * eg. Malayalam, Bengali, and Devanagari. We don't currently know about
+ * other scripts, so we block Kannada.
+ *
+ * Kannada test case:
+ * U+0C9A,U+0CCD,U+0C9A,U+0CCD
+ * With some versions of Lohit Kannada.
+ * https://bugs.freedesktop.org/show_bug.cgi?id=59118
+ *
+ * Malayalam test case:
+ * U+0D38,U+0D4D,U+0D31,U+0D4D,U+0D31,U+0D4D
+ * With lohit-ttf-20121122/Lohit-Malayalam.ttf
+ *
+ * Bengali test case:
+ * U+0998,U+09CD,U+09AF,U+09CD
+ * With Windows XP vrinda.ttf
+ * https://github.com/harfbuzz/harfbuzz/issues/1073
+ *
+ * Devanagari test case:
+ * U+091F,U+094D,U+0930,U+094D
+ * With chandas.ttf
+ * https://github.com/harfbuzz/harfbuzz/issues/1071
+ */
+ if (indic_plan->is_old_spec)
+ {
+ bool disallow_double_halants = buffer->props.script == HB_SCRIPT_KANNADA;
+ 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]) ||
+ (disallow_double_halants && 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_UNSAFE (info[i].indic_category()) & (JOINER_FLAGS | FLAG (OT_N) | FLAG (OT_RS) | MEDIAL_FLAGS | FLAG (OT_H))))
+ {
+ 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();
+ }
+ }
+ }
+ /* For post-base consonants let them own anything before them
+ * since the last consonant or matra. */
+ {
+ unsigned int last = base;
+ for (unsigned int i = base + 1; i < end; i++)
+ if (is_consonant (info[i]))
+ {
+ for (unsigned int j = last + 1; j < i; j++)
+ if (info[j].indic_position() < POS_SMVD)
+ info[j].indic_position() = info[i].indic_position();
+ last = i;
+ } else if (info[i].indic_category() == OT_M)
+ last = i;
+ }
+
+
+ {
+ /* 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_stable_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.
+ *
+ * We could use buffer->sort() for this, if there was no special
+ * reordering of pre-base stuff happening later...
+ * We don't want to merge_clusters all of that, which buffer->sort()
+ * would. Here's a concrete example:
+ *
+ * Assume there's a pre-base consonant and explicit Halant before base,
+ * followed by a prebase-reordering (left) Matra:
+ *
+ * C,H,ZWNJ,B,M
+ *
+ * At this point in reordering we would have:
+ *
+ * M,C,H,ZWNJ,B
+ *
+ * whereas in final reordering we will bring the Matra closer to Base:
+ *
+ * C,H,ZWNJ,M,B
+ *
+ * That's why we don't want to merge-clusters anything before the Base
+ * at this point. But if something moved from after Base to before it,
+ * we should merge clusters from base to them. In final-reordering, we
+ * only move things around before base, and merge-clusters up to base.
+ * These two merge-clusters from the two sides of base will interlock
+ * to merge things correctly. See:
+ * https://github.com/harfbuzz/harfbuzz/issues/2272
+ */
+ if (indic_plan->is_old_spec || end - start > 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 min = i;
+ unsigned int max = i;
+ unsigned int j = start + info[i].syllable();
+ while (j != i)
+ {
+ min = hb_min (min, j);
+ max = hb_max (max, j);
+ unsigned int next = start + info[j].syllable();
+ info[j].syllable() = 255; /* So we don't process j later again. */
+ j = next;
+ }
+ buffer->merge_clusters (hb_max (base, min), 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[INDIC_RPHF];
+
+ /* Pre-base */
+ mask = indic_plan->mask_array[INDIC_HALF];
+ if (!indic_plan->is_old_spec &&
+ indic_plan->config->blwf_mode == BLWF_MODE_PRE_AND_POST)
+ mask |= indic_plan->mask_array[INDIC_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[INDIC_BLWF] |
+ indic_plan->mask_array[INDIC_ABVF] |
+ indic_plan->mask_array[INDIC_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[INDIC_BLWF];
+ info[i+1].mask |= indic_plan->mask_array[INDIC_BLWF];
+ }
+ }
+
+ unsigned int pref_len = 2;
+ if (indic_plan->mask_array[INDIC_PREF] && base + pref_len < end)
+ {
+ /* Find a Halant,Ra sequence and mark it for pre-base-reordering processing. */
+ for (unsigned int i = base + 1; i + pref_len - 1 < end; i++) {
+ hb_codepoint_t glyphs[2];
+ for (unsigned int j = 0; j < pref_len; j++)
+ glyphs[j] = info[i + j].codepoint;
+ if (indic_plan->pref.would_substitute (glyphs, pref_len, face))
+ {
+ for (unsigned int j = 0; j < pref_len; j++)
+ info[i++].mask |= indic_plan->mask_array[INDIC_PREF];
+ 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[INDIC_HALF];
+
+ } while (j > start && !is_consonant (info[j]));
+ }
+}
+
+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 placeholder/dotted-circle as if they are consonants, so we
+ * should just chain. Only if not in compatibility mode that is... */
+
+ const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) plan->data;
+ if (indic_plan->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_syllable_indic (const hb_ot_shape_plan_t *plan,
+ hb_face_t *face,
+ hb_buffer_t *buffer,
+ unsigned int start, unsigned int end)
+{
+ indic_syllable_type_t syllable_type = (indic_syllable_type_t) (buffer->info[start].syllable() & 0x0F);
+ switch (syllable_type)
+ {
+ case indic_vowel_syllable: /* We made the vowels look like consonants. So let's call the consonant logic! */
+ case indic_consonant_syllable:
+ initial_reordering_consonant_syllable (plan, face, buffer, start, end);
+ break;
+
+ case indic_broken_cluster: /* We already inserted dotted-circles, so just call the standalone_cluster. */
+ case indic_standalone_cluster:
+ initial_reordering_standalone_cluster (plan, face, buffer, start, end);
+ break;
+
+ case indic_symbol_cluster:
+ case indic_non_indic_cluster:
+ break;
+ }
+}
+
+static void
+initial_reordering_indic (const hb_ot_shape_plan_t *plan,
+ hb_font_t *font,
+ hb_buffer_t *buffer)
+{
+ if (!buffer->message (font, "start reordering indic initial"))
+ return;
+
+ update_consonant_positions_indic (plan, font, buffer);
+ hb_syllabic_insert_dotted_circles (font, buffer,
+ indic_broken_cluster,
+ OT_DOTTEDCIRCLE,
+ OT_Repha,
+ POS_END);
+
+ foreach_syllable (buffer, start, end)
+ initial_reordering_syllable_indic (plan, font->face, buffer, start, end);
+
+ (void) buffer->message (font, "end reordering indic initial");
+}
+
+static void
+final_reordering_syllable_indic (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;
+
+
+ /* This function relies heavily on halant glyphs. Lots of ligation
+ * and possibly multiple substitutions happened prior to this
+ * phase, and that might have messed up our properties. Recover
+ * from a particular case of that where we're fairly sure that a
+ * class of OT_H is desired but has been lost. */
+ /* We don't call load_virama_glyph(), since we know it's already
+ * loaded. */
+ hb_codepoint_t virama_glyph = indic_plan->virama_glyph.get_relaxed ();
+ if (virama_glyph)
+ {
+ for (unsigned int i = start; i < end; i++)
+ if (info[i].codepoint == virama_glyph &&
+ _hb_glyph_info_ligated (&info[i]) &&
+ _hb_glyph_info_multiplied (&info[i]))
+ {
+ /* This will make sure that this glyph passes is_halant() test. */
+ info[i].indic_category() = OT_H;
+ _hb_glyph_info_clear_ligated_and_multiplied (&info[i]);
+ }
+ }
+
+
+ /* 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
+ * syllable.
+ */
+
+ bool try_pref = !!indic_plan->mask_array[INDIC_PREF];
+
+ /* Find base again */
+ unsigned int base;
+ for (base = start; base < end; base++)
+ if (info[base].indic_position() >= POS_BASE_C)
+ {
+ if (try_pref && base + 1 < end)
+ {
+ for (unsigned int i = base + 1; i < end; i++)
+ if ((info[i].mask & indic_plan->mask_array[INDIC_PREF]) != 0)
+ {
+ if (!(_hb_glyph_info_substituted (&info[i]) &&
+ _hb_glyph_info_ligated_and_didnt_multiply (&info[i])))
+ {
+ /* Ok, this was a 'pref' candidate but didn't form any.
+ * Base is around here... */
+ base = i;
+ while (base < end && is_halant (info[base]))
+ base++;
+ info[base].indic_position() = POS_BASE_C;
+
+ try_pref = false;
+ }
+ break;
+ }
+ }
+ /* For Malayalam, skip over unformed below- (but NOT post-) forms. */
+ if (buffer->props.script == HB_SCRIPT_MALAYALAM)
+ {
+ for (unsigned int i = base + 1; i < end; i++)
+ {
+ while (i < end && is_joiner (info[i]))
+ i++;
+ if (i == end || !is_halant (info[i]))
+ break;
+ i++; /* Skip halant. */
+ while (i < end && is_joiner (info[i]))
+ i++;
+ if (i < end && is_consonant (info[i]) && info[i].indic_position() == POS_BELOW_C)
+ {
+ base = i;
+ info[base].indic_position() = POS_BASE_C;
+ }
+ }
+ }
+
+ if (start < base && info[base].indic_position() > POS_BASE_C)
+ base--;
+ break;
+ }
+ if (base == end && start < base &&
+ is_one_of (info[base - 1], FLAG (OT_ZWJ)))
+ base--;
+ if (base < end)
+ while (start < base &&
+ is_one_of (info[base], (FLAG (OT_N) | FLAG (OT_H))))
+ 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.
+ *
+ * IMPLEMENTATION NOTES:
+ *
+ * It looks like the last sentence is wrong. Testing, with Windows 7 Uniscribe
+ * and Devanagari shows that the behavior is best described as:
+ *
+ * "If ZWJ follows this halant, matra is NOT repositioned after this halant.
+ * If ZWNJ follows this halant, position is moved after it."
+ *
+ * Test case, with Adobe Devanagari or Nirmala UI:
+ *
+ * U+091F,U+094D,U+200C,U+092F,U+093F
+ * (Matra moves to the middle, after ZWNJ.)
+ *
+ * U+091F,U+094D,U+200D,U+092F,U+093F
+ * (Matra does NOT move, stays to the left.)
+ *
+ * https://github.com/harfbuzz/harfbuzz/issues/1070
+ */
+
+ 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)
+ {
+ search:
+ while (new_pos > start &&
+ !(is_one_of (info[new_pos], (FLAG (OT_M) | FLAG (OT_H)))))
+ 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 (info[new_pos]) &&
+ info[new_pos].indic_position() != POS_PRE_M)
+ {
+#if 0 // See comment above
+ /* -> 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++;
+#endif
+ if (new_pos + 1 < end)
+ {
+ /* -> If ZWJ follows this halant, matra is NOT repositioned after this halant. */
+ if (info[new_pos + 1].indic_category() == OT_ZWJ)
+ {
+ /* Keep searching. */
+ if (new_pos > start)
+ {
+ new_pos--;
+ goto search;
+ }
+ }
+ /* -> If ZWNJ follows this halant, position is moved after it.
+ *
+ * IMPLEMENTATION NOTES:
+ *
+ * This is taken care of by the state-machine. A Halant,ZWNJ is a terminating
+ * sequence for a consonant syllable; any pre-base matras occurring after it
+ * will belong to the subsequent syllable.
+ */
+ }
+ }
+ 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;
+ if (old_pos < base && base <= new_pos) /* Shouldn't actually happen. */
+ base--;
+
+ 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;
+
+ /* Note: this merge_clusters() is intentionally *after* the reordering.
+ * Indic matra reordering is special and tricky... */
+ buffer->merge_clusters (new_pos, hb_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, hb_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) ^
+ _hb_glyph_info_ligated_and_didnt_multiply (&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 (info[new_reph_pos]))
+ new_reph_pos++;
+
+ if (new_reph_pos < base && is_halant (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 + 1 < end &&
+ !( FLAG_UNSAFE (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 (info[new_reph_pos]))
+ new_reph_pos++;
+
+ if (new_reph_pos < base && is_halant (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;
+ }
+ }
+ /* See https://github.com/harfbuzz/harfbuzz/issues/2298#issuecomment-615318654 */
+
+ /* 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 (!indic_plan->uniscribe_bug_compatible &&
+ unlikely (is_halant (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:
+ {
+ /* Move */
+ buffer->merge_clusters (start, new_reph_pos + 1);
+ 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 (try_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[INDIC_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.)
+ */
+ /* Note: We just check that something got substituted. We don't check that
+ * the <pref> feature actually did it...
+ *
+ * Reorder pref only if it ligated. */
+ if (_hb_glyph_info_ligated_and_didnt_multiply (&info[i]))
+ {
+ /*
+ * 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) | FLAG (OT_H))))
+ new_pos--;
+ }
+
+ if (new_pos > start && is_halant (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)
+ {
+ if (!start ||
+ !(FLAG_UNSAFE (_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[INDIC_INIT];
+ else
+ buffer->unsafe_to_break (start - 1, start + 1);
+ }
+
+
+ /*
+ * Finish off the clusters and go home!
+ */
+ if (indic_plan->uniscribe_bug_compatible)
+ {
+ switch ((hb_tag_t) plan->props.script)
+ {
+ case HB_SCRIPT_TAMIL:
+ case HB_SCRIPT_SINHALA:
+ break;
+
+ default:
+ /* Uniscribe merges the entire syllable into a single cluster... Except for Tamil & Sinhala.
+ * This means, half forms are submerged into the main consonant's cluster.
+ * This is unnecessary, and makes cursor positioning harder, but that's what
+ * Uniscribe does. */
+ buffer->merge_clusters (start, end);
+ break;
+ }
+ }
+}
+
+
+static void
+final_reordering_indic (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;
+
+ if (buffer->message (font, "start reordering indic final")) {
+ foreach_syllable (buffer, start, end)
+ final_reordering_syllable_indic (plan, buffer, start, end);
+ (void) buffer->message (font, "end reordering indic final");
+ }
+
+ HB_BUFFER_DEALLOCATE_VAR (buffer, indic_category);
+ HB_BUFFER_DEALLOCATE_VAR (buffer, indic_position);
+}
+
+
+static void
+preprocess_text_indic (const hb_ot_shape_plan_t *plan,
+ hb_buffer_t *buffer,
+ hb_font_t *font)
+{
+ _hb_preprocess_text_vowel_constraints (plan, buffer, font);
+}
+
+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 0x0931u : return false; /* DEVANAGARI LETTER RRA */
+ // https://github.com/harfbuzz/harfbuzz/issues/779
+ case 0x09DCu : return false; /* BENGALI LETTER RRA */
+ case 0x09DDu : return false; /* BENGALI LETTER RHA */
+ case 0x0B94u : return false; /* TAMIL LETTER AU */
+
+
+ /*
+ * Decompose split matras that don't have Unicode decompositions.
+ */
+
+#if 0
+ /* Gujarati */
+ /* This one has no decomposition in Unicode, but needs no decomposition either. */
+ /* case 0x0AC9u : return false; */
+
+ /* Oriya */
+ case 0x0B57u : *a = no decomp, -> RIGHT; return true;
+#endif
+ }
+
+ if ((ab == 0x0DDAu || hb_in_range<hb_codepoint_t> (ab, 0x0DDCu, 0x0DDEu)))
+ {
+ /*
+ * 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:
+ *
+ * https://docs.microsoft.com/en-us/typography/script-development/sinhala#shaping
+ */
+
+
+ const indic_shape_plan_t *indic_plan = (const indic_shape_plan_t *) c->plan->data;
+ hb_codepoint_t glyph;
+ if (indic_plan->uniscribe_bug_compatible ||
+ (c->font->get_nominal_glyph (ab, &glyph) &&
+ indic_plan->pstf.would_substitute (&glyph, 1, c->font->face)))
+ {
+ /* Ok, safe to use Uniscribe-style decomposition. */
+ *a = 0x0DD9u;
+ *b = ab;
+ return true;
+ }
+ }
+
+ return (bool) 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 == 0x09AFu && b == 0x09BCu) { *ab = 0x09DFu; return true; }
+
+ return (bool) c->unicode->compose (a, b, ab);
+}
+
+
+const hb_ot_shaper_t _hb_ot_shaper_indic =
+{
+ collect_features_indic,
+ override_features_indic,
+ data_create_indic,
+ data_destroy_indic,
+ preprocess_text_indic,
+ nullptr, /* postprocess_glyphs */
+ HB_OT_SHAPE_NORMALIZATION_MODE_COMPOSED_DIACRITICS_NO_SHORT_CIRCUIT,
+ decompose_indic,
+ compose_indic,
+ setup_masks_indic,
+ HB_TAG_NONE, /* gpos_tag */
+ nullptr, /* reorder_marks */
+ HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
+ false, /* fallback_position */
+};
+
+
+#endif
