[ot] Add Hangul shaper
Not exhaustively tested, but I think I got the intended logic right. The logic can perhaps be simplified. Maybe we should disabled normalization with this shaper. Then again, for now focusing on correctness.
This commit is contained in:
Behdad Esfahbod
parent
15f67048e4
commit
c98b7183f7
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@ -92,6 +92,7 @@ HBSOURCES += \
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hb-ot-shape-complex-arabic-fallback.hh \
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hb-ot-shape-complex-arabic-table.hh \
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hb-ot-shape-complex-default.cc \
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hb-ot-shape-complex-hangul.cc \
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hb-ot-shape-complex-indic.cc \
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hb-ot-shape-complex-indic-machine.hh \
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hb-ot-shape-complex-indic-private.hh \
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@ -32,14 +32,6 @@
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/* The default shaper *only* adds additional per-script features.*/
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static const hb_tag_t hangul_features[] =
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{
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HB_TAG('l','j','m','o'),
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HB_TAG('v','j','m','o'),
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HB_TAG('t','j','m','o'),
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HB_TAG_NONE
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};
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static const hb_tag_t tibetan_features[] =
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{
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HB_TAG('a','b','v','s'),
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@ -56,11 +48,6 @@ collect_features_default (hb_ot_shape_planner_t *plan)
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switch ((hb_tag_t) plan->props.script)
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{
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/* Unicode-1.1 additions */
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case HB_SCRIPT_HANGUL:
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script_features = hangul_features;
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break;
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/* Unicode-2.0 additions */
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case HB_SCRIPT_TIBETAN:
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script_features = tibetan_features;
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@ -0,0 +1,232 @@
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/*
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* Copyright © 2013 Google, Inc.
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*
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* This is part of HarfBuzz, a text shaping library.
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*
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* Permission is hereby granted, without written agreement and without
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* license or royalty fees, to use, copy, modify, and distribute this
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* software and its documentation for any purpose, provided that the
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* above copyright notice and the following two paragraphs appear in
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* all copies of this software.
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*
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* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
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* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
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* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
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* DAMAGE.
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*
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* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
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* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
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* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
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* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
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* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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*
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* Google Author(s): Behdad Esfahbod
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*/
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#include "hb-ot-shape-complex-private.hh"
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/* Hangul shaper */
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static const hb_tag_t hangul_features[] =
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{
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HB_TAG('l','j','m','o'),
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HB_TAG('v','j','m','o'),
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HB_TAG('t','j','m','o'),
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HB_TAG_NONE
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};
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static void
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collect_features_hangul (hb_ot_shape_planner_t *plan)
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{
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for (const hb_tag_t *script_features = hangul_features; script_features && *script_features; script_features++)
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plan->map.add_global_bool_feature (*script_features);
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}
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#define LBase 0x1100
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#define VBase 0x1161
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#define TBase 0x11A7
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#define LCount 19
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#define VCount 21
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#define TCount 28
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#define SBase 0xAC00
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#define NCount (VCount * TCount)
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#define SCount (LCount * NCount)
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#define isCombiningL(u) (hb_in_range<hb_codepoint_t> ((u), LBase, LBase+LCount-1))
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#define isCombiningV(u) (hb_in_range<hb_codepoint_t> ((u), VBase, VBase+VCount-1))
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#define isCombiningT(u) (hb_in_range<hb_codepoint_t> ((u), TBase+1, TBase+TCount-1))
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#define isCombinedS(u) (hb_in_range<hb_codepoint_t> ((u), SBase, SBase+SCount-1))
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#define isT(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x11A8, 0x11FF, 0xD7C8, 0xD7FF))
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static void
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preprocess_text_hangul (const hb_ot_shape_plan_t *plan,
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hb_buffer_t *buffer,
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hb_font_t *font)
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{
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/* Hangul syllables come in two shapes: LV, and LVT. Of those:
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*
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* - LV can be precomposed, or decomposed. Lets call those
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* <LV> and <L,V>,
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* - LVT can be fully precomposed, partically precomposed, or
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* fully decomposed. Ie. <LVT>, <LV,T>, or <L,V,T>.
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*
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* The composition / decomposition is mechanical. However, not
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* all <L,V> sequences compose, and not all <LV,T> sequences
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* compose.
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*
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* Here are the specifics:
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*
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* - <L>: U+1100..115F, U+A960..A97F
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* - <V>: U+1160..11A7, U+D7B0..D7C7
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* - <T>: U+11A8..11FF, U+D7C8..D7FF
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*
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* - Only the <L,V> sequences for the 11xx ranges combine.
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* - Only <LV,T> sequences for T in U+11A8..11C3 combine.
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*
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* Here is what we want to accomplish in this shaper:
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*
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* - If the whole syllable can be precomposed, do that,
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* - Otherwise, fully decompose.
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*
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* That is, of the different possible syllables:
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*
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* <L>
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* <L,V>
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* <L,V,T>
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* <LV>
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* <LVT>
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* <LV, T>
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*
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* - <L> needs no work.
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*
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* - <LV> and <LVT> can stay the way they are if the font supports them, otherwise we
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* should fully decompose them if font supports.
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*
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* - <L,V> and <L,V,T> we should compose if the whole thing can be composed.
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*
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* - <LV,T> we should compose if the whole thing can be composed, otherwise we should
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* decompose.
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*/
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buffer->clear_output ();
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unsigned int count = buffer->len;
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for (buffer->idx = 0; buffer->idx < count;)
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{
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hb_codepoint_t u = buffer->cur().codepoint;
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if (isCombiningL(u) && buffer->idx + 1 < count)
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{
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hb_codepoint_t l = u;
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hb_codepoint_t v = buffer->cur(+1).codepoint;
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if (isCombiningV(v))
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{
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/* Have <L,V> or <L,V,T>. */
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unsigned int len = 2;
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unsigned int tindex = 0;
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if (buffer->idx + 2 < count)
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{
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hb_codepoint_t t = buffer->cur(+2).codepoint;
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if (isCombiningT(t))
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{
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len = 3;
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tindex = t - TBase;
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}
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else if (isT (t))
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{
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/* Old T jamo. Doesn't combine. Don't combine *anything*. */
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len = 0;
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}
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}
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if (len)
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{
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hb_codepoint_t s = SBase + (l - LBase) * NCount + (v - VBase) * TCount + tindex;
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hb_codepoint_t glyph;
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if (font->get_glyph (s, 0, &glyph))
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{
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buffer->replace_glyphs (len, 1, &s);
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if (unlikely (buffer->in_error))
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return;
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continue;
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}
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}
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}
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}
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else if (isCombinedS(u))
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{
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/* Have <LV>, <LVT>, or <LV,T> */
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hb_codepoint_t s = u;
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hb_codepoint_t glyph;
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bool has_glyph = font->get_glyph (s, 0, &glyph);
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unsigned int lindex = (s - SBase) / NCount;
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unsigned int nindex = (s - SBase) % NCount;
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unsigned int vindex = nindex / VCount;
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unsigned int tindex = nindex % VCount;
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if (tindex && has_glyph)
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goto next; /* <LVT> supported. Nothing to do. */
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if (!tindex &&
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buffer->idx + 1 < count &&
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isCombiningT (buffer->cur(+1).codepoint))
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{
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/* <LV,T>, try to combine. */
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tindex = buffer->cur(+1).codepoint - TBase;
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hb_codepoint_t new_s = s + tindex;
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if (font->get_glyph (new_s, 0, &glyph))
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{
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buffer->replace_glyphs (2, 1, &new_s);
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if (unlikely (buffer->in_error))
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return;
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continue;
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}
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}
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/* Otherwise, decompose if font doesn't support <LV>,
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* or if having non-combining <LV,T>. Note that we
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* already handled combining <LV,T> above. */
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if (!has_glyph ||
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(buffer->idx + 1 < count &&
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isT (buffer->cur(+1).codepoint)))
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{
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hb_codepoint_t decomposed[3] = {LBase + lindex,
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VBase + vindex,
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TBase + tindex};
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if (font->get_glyph (decomposed[0], 0, &glyph) &&
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font->get_glyph (decomposed[1], 0, &glyph) &&
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(tindex && font->get_glyph (decomposed[2], 0, &glyph)))
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{
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buffer->replace_glyphs (1, tindex ? 3 : 2, decomposed);
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if (unlikely (buffer->in_error))
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return;
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continue;
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}
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}
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}
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next:
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buffer->next_glyph ();
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}
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buffer->swap_buffers ();
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}
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const hb_ot_complex_shaper_t _hb_ot_complex_shaper_hangul =
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{
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"hangul",
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collect_features_hangul,
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NULL, /* override_features */
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NULL, /* data_create */
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NULL, /* data_destroy */
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preprocess_text_hangul,
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NULL, /* normalization_preference */
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NULL, /* decompose */
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NULL, /* compose */
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NULL, /* setup_masks */
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HB_OT_SHAPE_ZERO_WIDTH_MARKS_BY_UNICODE_LATE,
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false, /* fallback_position */
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};
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@ -52,6 +52,7 @@ enum hb_ot_shape_zero_width_marks_type_t {
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#define HB_COMPLEX_SHAPERS_IMPLEMENT_SHAPERS \
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HB_COMPLEX_SHAPER_IMPLEMENT (default) /* should be first */ \
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HB_COMPLEX_SHAPER_IMPLEMENT (arabic) \
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HB_COMPLEX_SHAPER_IMPLEMENT (hangul) \
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HB_COMPLEX_SHAPER_IMPLEMENT (indic) \
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HB_COMPLEX_SHAPER_IMPLEMENT (myanmar) \
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HB_COMPLEX_SHAPER_IMPLEMENT (sea) \
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@ -189,19 +190,10 @@ hb_ot_shape_complex_categorize (const hb_ot_shape_planner_t *planner)
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return &_hb_ot_complex_shaper_thai;
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#if 0
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/* Note:
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* Currently we don't have a separate Hangul shaper. The default shaper handles
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* Hangul by enabling jamo features. We may want to implement a separate shaper
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* in the future. See this thread for details of what such a shaper would do:
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*
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* http://lists.freedesktop.org/archives/harfbuzz/2013-April/003070.html
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*/
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/* Unicode-1.1 additions */
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case HB_SCRIPT_HANGUL:
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return &_hb_ot_complex_shaper_hangul;
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#endif
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/* ^--- Add new shapers here */
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@ -807,6 +807,12 @@ hb_in_range (T u, T lo, T hi)
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return lo <= u && u <= hi;
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}
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template <typename T> static inline bool
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hb_in_ranges (T u, T lo1, T hi1, T lo2, T hi2)
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{
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return hb_in_range (u, lo1, hi1) || hb_in_range (u, lo2, hi2);
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}
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template <typename T> static inline bool
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hb_in_ranges (T u, T lo1, T hi1, T lo2, T hi2, T lo3, T hi3)
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{
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