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+/*
+ * Copyright © 2013 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.hh"
+
+
+/* Hangul shaper */
+
+
+/* Same order as the feature array below */
+enum {
+ _JMO,
+
+ LJMO,
+ VJMO,
+ TJMO,
+
+ FIRST_HANGUL_FEATURE = LJMO,
+ HANGUL_FEATURE_COUNT = TJMO + 1
+};
+
+static const hb_tag_t hangul_features[HANGUL_FEATURE_COUNT] =
+{
+ HB_TAG_NONE,
+ HB_TAG('l','j','m','o'),
+ HB_TAG('v','j','m','o'),
+ HB_TAG('t','j','m','o')
+};
+
+static void
+collect_features_hangul (hb_ot_shape_planner_t *plan)
+{
+ hb_ot_map_builder_t *map = &plan->map;
+
+ for (unsigned int i = FIRST_HANGUL_FEATURE; i < HANGUL_FEATURE_COUNT; i++)
+ map->add_feature (hangul_features[i]);
+}
+
+static void
+override_features_hangul (hb_ot_shape_planner_t *plan)
+{
+ /* Uniscribe does not apply 'calt' for Hangul, and certain fonts
+ * (Noto Sans CJK, Source Sans Han, etc) apply all of jamo lookups
+ * in calt, which is not desirable. */
+ plan->map.disable_feature (HB_TAG('c','a','l','t'));
+}
+
+struct hangul_shape_plan_t
+{
+ hb_mask_t mask_array[HANGUL_FEATURE_COUNT];
+};
+
+static void *
+data_create_hangul (const hb_ot_shape_plan_t *plan)
+{
+ hangul_shape_plan_t *hangul_plan = (hangul_shape_plan_t *) hb_calloc (1, sizeof (hangul_shape_plan_t));
+ if (unlikely (!hangul_plan))
+ return nullptr;
+
+ for (unsigned int i = 0; i < HANGUL_FEATURE_COUNT; i++)
+ hangul_plan->mask_array[i] = plan->map.get_1_mask (hangul_features[i]);
+
+ return hangul_plan;
+}
+
+static void
+data_destroy_hangul (void *data)
+{
+ hb_free (data);
+}
+
+/* Constants for algorithmic hangul syllable [de]composition. */
+#define LBase 0x1100u
+#define VBase 0x1161u
+#define TBase 0x11A7u
+#define LCount 19u
+#define VCount 21u
+#define TCount 28u
+#define SBase 0xAC00u
+#define NCount (VCount * TCount)
+#define SCount (LCount * NCount)
+
+#define isCombiningL(u) (hb_in_range<hb_codepoint_t> ((u), LBase, LBase+LCount-1))
+#define isCombiningV(u) (hb_in_range<hb_codepoint_t> ((u), VBase, VBase+VCount-1))
+#define isCombiningT(u) (hb_in_range<hb_codepoint_t> ((u), TBase+1, TBase+TCount-1))
+#define isCombinedS(u) (hb_in_range<hb_codepoint_t> ((u), SBase, SBase+SCount-1))
+
+#define isL(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1100u, 0x115Fu, 0xA960u, 0xA97Cu))
+#define isV(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x1160u, 0x11A7u, 0xD7B0u, 0xD7C6u))
+#define isT(u) (hb_in_ranges<hb_codepoint_t> ((u), 0x11A8u, 0x11FFu, 0xD7CBu, 0xD7FBu))
+
+#define isHangulTone(u) (hb_in_range<hb_codepoint_t> ((u), 0x302Eu, 0x302Fu))
+
+/* buffer var allocations */
+#define hangul_shaping_feature() ot_shaper_var_u8_auxiliary() /* hangul jamo shaping feature */
+
+static bool
+is_zero_width_char (hb_font_t *font,
+ hb_codepoint_t unicode)
+{
+ hb_codepoint_t glyph;
+ return hb_font_get_glyph (font, unicode, 0, &glyph) && hb_font_get_glyph_h_advance (font, glyph) == 0;
+}
+
+static void
+preprocess_text_hangul (const hb_ot_shape_plan_t *plan HB_UNUSED,
+ hb_buffer_t *buffer,
+ hb_font_t *font)
+{
+ HB_BUFFER_ALLOCATE_VAR (buffer, hangul_shaping_feature);
+
+ /* Hangul syllables come in two shapes: LV, and LVT. Of those:
+ *
+ * - LV can be precomposed, or decomposed. Lets call those
+ * <LV> and <L,V>,
+ * - LVT can be fully precomposed, partially precomposed, or
+ * fully decomposed. Ie. <LVT>, <LV,T>, or <L,V,T>.
+ *
+ * The composition / decomposition is mechanical. However, not
+ * all <L,V> sequences compose, and not all <LV,T> sequences
+ * compose.
+ *
+ * Here are the specifics:
+ *
+ * - <L>: U+1100..115F, U+A960..A97F
+ * - <V>: U+1160..11A7, U+D7B0..D7C7
+ * - <T>: U+11A8..11FF, U+D7CB..D7FB
+ *
+ * - Only the <L,V> sequences for some of the U+11xx ranges combine.
+ * - Only <LV,T> sequences for some of the Ts in U+11xx range combine.
+ *
+ * Here is what we want to accomplish in this shaper:
+ *
+ * - If the whole syllable can be precomposed, do that,
+ * - Otherwise, fully decompose and apply ljmo/vjmo/tjmo features.
+ * - If a valid syllable is followed by a Hangul tone mark, reorder the tone
+ * mark to precede the whole syllable - unless it is a zero-width glyph, in
+ * which case we leave it untouched, assuming it's designed to overstrike.
+ *
+ * That is, of the different possible syllables:
+ *
+ * <L>
+ * <L,V>
+ * <L,V,T>
+ * <LV>
+ * <LVT>
+ * <LV, T>
+ *
+ * - <L> needs no work.
+ *
+ * - <LV> and <LVT> can stay the way they are if the font supports them, otherwise we
+ * should fully decompose them if font supports.
+ *
+ * - <L,V> and <L,V,T> we should compose if the whole thing can be composed.
+ *
+ * - <LV,T> we should compose if the whole thing can be composed, otherwise we should
+ * decompose.
+ */
+
+ buffer->clear_output ();
+ unsigned int start = 0, end = 0; /* Extent of most recently seen syllable;
+ * valid only if start < end
+ */
+ unsigned int count = buffer->len;
+
+ for (buffer->idx = 0; buffer->idx < count && buffer->successful;)
+ {
+ hb_codepoint_t u = buffer->cur().codepoint;
+
+ if (isHangulTone (u))
+ {
+ /*
+ * We could cache the width of the tone marks and the existence of dotted-circle,
+ * but the use of the Hangul tone mark characters seems to be rare enough that
+ * I didn't bother for now.
+ */
+ if (start < end && end == buffer->out_len)
+ {
+ /* Tone mark follows a valid syllable; move it in front, unless it's zero width. */
+ buffer->unsafe_to_break_from_outbuffer (start, buffer->idx);
+ if (unlikely (!buffer->next_glyph ())) break;
+ if (!is_zero_width_char (font, u))
+ {
+ buffer->merge_out_clusters (start, end + 1);
+ hb_glyph_info_t *info = buffer->out_info;
+ hb_glyph_info_t tone = info[end];
+ memmove (&info[start + 1], &info[start], (end - start) * sizeof (hb_glyph_info_t));
+ info[start] = tone;
+ }
+ }
+ else
+ {
+ /* No valid syllable as base for tone mark; try to insert dotted circle. */
+ if (!(buffer->flags & HB_BUFFER_FLAG_DO_NOT_INSERT_DOTTED_CIRCLE) &&
+ font->has_glyph (0x25CCu))
+ {
+ hb_codepoint_t chars[2];
+ if (!is_zero_width_char (font, u))
+ {
+ chars[0] = u;
+ chars[1] = 0x25CCu;
+ } else
+ {
+ chars[0] = 0x25CCu;
+ chars[1] = u;
+ }
+ (void) buffer->replace_glyphs (1, 2, chars);
+ }
+ else
+ {
+ /* No dotted circle available in the font; just leave tone mark untouched. */
+ (void) buffer->next_glyph ();
+ }
+ }
+ start = end = buffer->out_len;
+ continue;
+ }
+
+ start = buffer->out_len; /* Remember current position as a potential syllable start;
+ * will only be used if we set end to a later position.
+ */
+
+ if (isL (u) && buffer->idx + 1 < count)
+ {
+ hb_codepoint_t l = u;
+ hb_codepoint_t v = buffer->cur(+1).codepoint;
+ if (isV (v))
+ {
+ /* Have <L,V> or <L,V,T>. */
+ hb_codepoint_t t = 0;
+ unsigned int tindex = 0;
+ if (buffer->idx + 2 < count)
+ {
+ t = buffer->cur(+2).codepoint;
+ if (isT (t))
+ tindex = t - TBase; /* Only used if isCombiningT (t); otherwise invalid. */
+ else
+ t = 0; /* The next character was not a trailing jamo. */
+ }
+ buffer->unsafe_to_break (buffer->idx, buffer->idx + (t ? 3 : 2));
+
+ /* We've got a syllable <L,V,T?>; see if it can potentially be composed. */
+ if (isCombiningL (l) && isCombiningV (v) && (t == 0 || isCombiningT (t)))
+ {
+ /* Try to compose; if this succeeds, end is set to start+1. */
+ hb_codepoint_t s = SBase + (l - LBase) * NCount + (v - VBase) * TCount + tindex;
+ if (font->has_glyph (s))
+ {
+ (void) buffer->replace_glyphs (t ? 3 : 2, 1, &s);
+ end = start + 1;
+ continue;
+ }
+ }
+
+ /* We didn't compose, either because it's an Old Hangul syllable without a
+ * precomposed character in Unicode, or because the font didn't support the
+ * necessary precomposed glyph.
+ * Set jamo features on the individual glyphs, and advance past them.
+ */
+ buffer->cur().hangul_shaping_feature() = LJMO;
+ (void) buffer->next_glyph ();
+ buffer->cur().hangul_shaping_feature() = VJMO;
+ (void) buffer->next_glyph ();
+ if (t)
+ {
+ buffer->cur().hangul_shaping_feature() = TJMO;
+ (void) buffer->next_glyph ();
+ end = start + 3;
+ }
+ else
+ end = start + 2;
+ if (unlikely (!buffer->successful))
+ break;
+ if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES)
+ buffer->merge_out_clusters (start, end);
+ continue;
+ }
+ }
+
+ else if (isCombinedS (u))
+ {
+ /* Have <LV>, <LVT>, or <LV,T> */
+ hb_codepoint_t s = u;
+ bool has_glyph = font->has_glyph (s);
+ unsigned int lindex = (s - SBase) / NCount;
+ unsigned int nindex = (s - SBase) % NCount;
+ unsigned int vindex = nindex / TCount;
+ unsigned int tindex = nindex % TCount;
+
+ if (!tindex &&
+ buffer->idx + 1 < count &&
+ isCombiningT (buffer->cur(+1).codepoint))
+ {
+ /* <LV,T>, try to combine. */
+ unsigned int new_tindex = buffer->cur(+1).codepoint - TBase;
+ hb_codepoint_t new_s = s + new_tindex;
+ if (font->has_glyph (new_s))
+ {
+ (void) buffer->replace_glyphs (2, 1, &new_s);
+ end = start + 1;
+ continue;
+ }
+ else
+ buffer->unsafe_to_break (buffer->idx, buffer->idx + 2); /* Mark unsafe between LV and T. */
+ }
+
+ /* Otherwise, decompose if font doesn't support <LV> or <LVT>,
+ * or if having non-combining <LV,T>. Note that we already handled
+ * combining <LV,T> above. */
+ if (!has_glyph ||
+ (!tindex &&
+ buffer->idx + 1 < count &&
+ isT (buffer->cur(+1).codepoint)))
+ {
+ hb_codepoint_t decomposed[3] = {LBase + lindex,
+ VBase + vindex,
+ TBase + tindex};
+ if (font->has_glyph (decomposed[0]) &&
+ font->has_glyph (decomposed[1]) &&
+ (!tindex || font->has_glyph (decomposed[2])))
+ {
+ unsigned int s_len = tindex ? 3 : 2;
+ (void) buffer->replace_glyphs (1, s_len, decomposed);
+
+ /* If we decomposed an LV because of a non-combining T following,
+ * we want to include this T in the syllable.
+ */
+ if (has_glyph && !tindex)
+ {
+ (void) buffer->next_glyph ();
+ s_len++;
+ }
+ if (unlikely (!buffer->successful))
+ break;
+
+ /* We decomposed S: apply jamo features to the individual glyphs
+ * that are now in buffer->out_info.
+ */
+ hb_glyph_info_t *info = buffer->out_info;
+ end = start + s_len;
+
+ unsigned int i = start;
+ info[i++].hangul_shaping_feature() = LJMO;
+ info[i++].hangul_shaping_feature() = VJMO;
+ if (i < end)
+ info[i++].hangul_shaping_feature() = TJMO;
+
+ if (buffer->cluster_level == HB_BUFFER_CLUSTER_LEVEL_MONOTONE_GRAPHEMES)
+ buffer->merge_out_clusters (start, end);
+ continue;
+ }
+ else if ((!tindex && buffer->idx + 1 < count && isT (buffer->cur(+1).codepoint)))
+ buffer->unsafe_to_break (buffer->idx, buffer->idx + 2); /* Mark unsafe between LV and T. */
+ }
+
+ if (has_glyph)
+ {
+ /* We didn't decompose the S, so just advance past it and fall through. */
+ end = start + 1;
+ }
+ }
+
+ /* Didn't find a recognizable syllable, so we leave end <= start;
+ * this will prevent tone-mark reordering happening.
+ */
+ (void) buffer->next_glyph ();
+ }
+ buffer->sync ();
+}
+
+static void
+setup_masks_hangul (const hb_ot_shape_plan_t *plan,
+ hb_buffer_t *buffer,
+ hb_font_t *font HB_UNUSED)
+{
+ const hangul_shape_plan_t *hangul_plan = (const hangul_shape_plan_t *) plan->data;
+
+ if (likely (hangul_plan))
+ {
+ unsigned int count = buffer->len;
+ hb_glyph_info_t *info = buffer->info;
+ for (unsigned int i = 0; i < count; i++, info++)
+ info->mask |= hangul_plan->mask_array[info->hangul_shaping_feature()];
+ }
+
+ HB_BUFFER_DEALLOCATE_VAR (buffer, hangul_shaping_feature);
+}
+
+
+const hb_ot_shaper_t _hb_ot_shaper_hangul =
+{
+ collect_features_hangul,
+ override_features_hangul,
+ data_create_hangul,
+ data_destroy_hangul,
+ preprocess_text_hangul,
+ nullptr, /* postprocess_glyphs */
+ HB_OT_SHAPE_NORMALIZATION_MODE_NONE,
+ nullptr, /* decompose */
+ nullptr, /* compose */
+ setup_masks_hangul,
+ HB_TAG_NONE, /* gpos_tag */
+ nullptr, /* reorder_marks */
+ HB_OT_SHAPE_ZERO_WIDTH_MARKS_NONE,
+ false, /* fallback_position */
+};
+
+
+#endif
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